United States
         Environmental Protection
         Agency
Office of Science and Technology
Office of Water
Washington, D.C. 20460
September 1995
vvEPA  1995
         Water Quality
         Criteria

-------
Quality Criteria
    for Water
        1995
        Prepared by

Health and Ecological Criteria Division
       Office of Water
U.S. Environmental Protection Agency
       Washington, D.C.
          1995

-------
                          NOTE TO  USERS
        Quality Criteria for Water 1995 is produced as a summary document.
        Individual criteria in this document are taken from previously published
        criteria. To obtain further information on these criteria, review the
        information in Appendix F. Each criteria entry lists the Federal Register
        notification and publication date.
           This publication contains criteria issued since 1976. Different meth-
        odologies have been used to derive these criteria. Appendixes A through
        D provide the various available methodologies; notes at the end of each
        criterion indicate which methodology applies.
           Individuals who use this document are encouraged to obtain a copy
        of the Criteria Document for the Pollutant of Interest. These documents con-
        tain the data sets and references upon which the criteria in this summary
        document were derived. This criteria document for the particular pollut-
        ant of interest  contains important information on the derivation of the
        criteria value and may provide material which should be considered in
        the implementation of criteria. Appendix F lists available ambient water
        quality criteria documents and how to obtain them.
11

-------
                         PREFACE
Section 304(a)(l) of the Clean Water Act (33 U.S.C. 1314[a][l] requires the
Environmental Protection Agency (EPA) to publish and  periodically
update ambient water quality criteria. Intended neither as rules  nor
regulations, these criteria present scientific data and guidance on the
environmental effects of pollutants that can be used to derive regulations
based on considerations of water quality impacts.
   These criteria are to accurately reflect the latest scientific knowledge
(a) on the kind and extent of all identifiable effects on health and welfare
including, but not limited to, plankton, fish, shellfish, wildlife, plant life,
shorelines, beaches, aesthetics, and recreation that may be expected from
the presence of pollutants in any body of water including groundwater;
(b) on the concentration and dispersal of pollutants, or their byproducts,
through biological, physical, and chemical processes; and (c) on the ef-
fects of pollutants on biological community diversity, productivity, and
stability, including information on the factors affecting rates of eutrophi-
cation  and organic and inorganic  sedimentation for varying types of
receiving waters.
   The first of these publications appeared in 1968 with The Report of the
National Technical Advisory Committee to the Secretary of the Interior "Green
Book."  Water Quality Criteria 1972 (the "Blue Book") was published in
1973, followed  three years later by the "Red Book,"  Quality Criteria for
Water.
   On November 28,  1980 (45 F.R. 79318), EPA announced  through the
Federal Register the publication of 64 individual ambient water quality
criteria documents for pollutants listed as toxic under section 307(a)(l)
of the Clean Water Act. On February 15,1984 (49 F.R. 5831); July 29,1985
(50 F.R. 30784); March  7,1986 (51 F.R. 8012); June 24,1986 (51 F.R. 22978);
December 3, 1986 (51 F.R. 43665); and March 2,1987  (52 F.R. 6213); EPA
published additional  water quality  criteria documents, followed by
Quality Criteria for Water 1986  (the "Gold Book"). The National Toxics
Rule (NTR) was promulgated on December 22,1993 (57 F.R. 60848). The
NTR was a national rulemaking that provided the most current criteria
for the priority pollutants.  This rulemaking recalculated  the human
health  priority pollutants criteria, based on data that was available at its
release. Quality Criteria for Water 1995 draws information from its prede-
cessors in presenting summaries of all the contaminants for which EPA
has developed criteria recommendations. The rationale for these recom-
mendations can be found in the reference identified at the  end of each
                                                                        111

-------
        criteria summary. This document is intended as a summary only. Specific
        data on each criterion can be found in individual criteria documents.
        Copies of the individual ambient water quality criteria documents con-
        taining  all  the  data  used  to  develop the criteria recommendations
        summarized here, are available from  National Technical Information
        Service, 5285 Port Royal Road, Springfield, VA 22161, (703) 487-4650.
            This book is intended for easy reference use. The Contents lists com-
        pounds by their common names.
            To obtain copies of this document and supplements, contact the Gov-
        ernment Printing Office at (202) 783-3238.
            EPA's goal is to continue to develop and make available ambient
        water quality criteria reflecting the latest scientific information. This, we
        believe, constitutes a major component in our ongoing commitment to
        improve and protect the quality of our Nation's waters.

                                 Margaret Stasikowski
                                 Director, Health and Ecological Criteria Division
        For further information contact:

                                Robert Cantilli or
                             Jennifer Orme-Zavaleta
                       Health and Ecological Criteria Division
                       U.S. Environmental Protection Agency
                             401M Street, SW (4304)
                              Washington, DC 20460
                      ACKNOWLEDGEMENT

        We would like to acknowledge Kennard W. Potts for his dedicated work
        in making this document a reality.
IV

-------
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Selene* and Technology
Health and Ecological Criteria Division (4304)
                        WATER QUALITY CRITERIA SUMMARY
                             CONCENTRATIONS (in  jig/L)
CASI gig
ACENAPHTHENE
ACENAPHTHYLENE
ACROLEIN
ACRYLONITRILE
ALACHLOR
ALDR1N
ALKALINITY
ALUMINUM
AMMONIA
ANTHRACENE
ANTIMONY
ARSENIC
ARSENIC(V)
ARSENIC(III)
ASBESTOS
ATRAZINE
BACTERIA
BARIUM
BENZENE
BENZIDINE
BENZOFLUORANTHENE, 3,4-
BENZO(A)
ANTHRACENE
BENZO(A)PYRENE
BENZO(GHI)PERYLENE
83-32-9
208-96-8
107-02-8
107-13-1
15972-60-8
309-00-2
—
7429-90-5
7664-41-7
120-12-7
7440-36-0
7440-38-2
17428-41-0
22569-72-8
1332-21-4
1912-24-9
—
7440-39-3
71-43-2
92-87-5
205-99-2
56-55-3
50-32-8
191-24-2
Y
Y
Y
Y
N
Y
N
N
N
Y
Y
Y
Y
Y
Y
N
N
N
Y
Y
Y
Y
Y
Y
HUMAN HEALTH (104 RISK LEVEL FOR CARCINOGENS)
|
N
Y
N
Y
Y
Y
N
N
N
Y
N
Y
Y
Y
Y
N
N
N
Y
Y
Y
Y
Y
Y
FRESH
CRITERION
HAXMUM
CONCENTRATION
•1,700.

•68.
•7,550.

3.0

FRESH
CRITERION
CONTINUOUS
CONCENTRATION
•520.

•21.
•2,600.


20,000.
SALTWATER SALTWATER
CRITERION CRITERION
MAXUtUM CONTINUOUS
CONCENTRATION CONCENTRATION
•970. »710.

•55.


1.3

PUBLISHED CRJTERA
WATER* ORGAMSMS
ORGANISMS ONLY


320. 780.
0.058 0.65

0.000074 0.000079

I RECALCULATED VALUES
luSMGfMS.ASOF12/12
WATER* ORGANISMS
ORGAMSMS ONLY
1,200.


0.059

0.00013

2,700.


0.66

0.00014

CRITERIA ARE pH DEPENDENT — SEE DOCUMENT
CRITERIA ARE pH AND TEMPERATURE DEPENDENT — SEE DOCUMENT

/p/88

•850.
360.



/p/30


190.



/p/1500 /p/500

•2,319.
69. 36.



146. 45,000.
0.0022 0.0175


30kfibers/L

9,600.
14.
0.018


7MFL

110,000.
4,300.
0.14




FOR PRIMARY RECREATION AND SHELLFISH USES — SEE DOCUMENT

•5,300.
•2,500.












•5,100 *700.





1,000.
0.66 40.
0.00012 0.00053





1.2
0.00012
0.0028
0.0028
0.0028


71.
0.00054
0.0311
0.0311
0.0311

CRITERIA
FEDERAL
DRINKING REGISTER
WATER MCL NOTICE
57 FR 60890
57 FR 6091 3
45 FR 79324
57 FR 60911
2.0 —
45 FR 79325
RB
53 FR 33178
54 FR 19227
57 FR 6091 3
6.0 45 FR 79325
50. 45 FR 79325
50 FR 30789
50 FR 30786
7 MFL 57 FR 60911
3.0 —
51 FR 8012
2,000. RB
5.0 57 FR 60911
57 FR 6091 3
57 FR 6091 3
57 FR 6091 3
0.2 57 FR 6091 3
57 FR 6091 3

-------
HUMAN HEALTH (104 RISK LEVEL FOR CARCINOGENS)

BENZO(K)
FLUORANTHENE
BERYLLIUM
BETA PARTICLE and
PHOTON ACTIVITY
BHC
BROMOFORM
BUTYLBENZYL
PHTHALATE
CADMIUM
CARBOFURAN
CARBON TETRACHLORIDE
CHLORDANE
CHLORIDE
CHLORINATED
BENZENES
CHLORINATED
NAPHTHALENES
CHLORINE
CHLOROALKYL
ETHERS
CHLOROBENZENE
CHLORODIBRO-
MOMETHANE
CHLOROFORM
CHLOROPHENOL, 2-
CHLOROPHENOL, 4-
CHLOROPHENOL, 4-,
METHYL, 3-
CHLOROPHENOXY
HERBICIDE (2,4,5,-TP)
CHLOROPHENOXY
HERBICIDE (2,4-D)
CHLORPYRIFOS
CHROMIUM (VI)
CHROMIUM (III)
CASI
207-08-9
7440-41-7

680-73-1
75-25-2
85-68-7
7440-43-9
1563-66-2
56-23-5
57-74-9
16887-00-6


7782-50-5

108-90-7
124-48-1
67-66-3
95-57-8
106-48-9
59-50-7
93-72-1
94-75-7
2921-88-2
18540297
1308-14-1
III
Y Y
Y Y
N Y
N Y
Y Y
Y N
Y N
N N
Y Y
Y Y
N N
Y Y
Y N
N N
Y N
Y N
Y Y
Y Y
Y N
N N
Y N
N N
N N
N N
Y N
Y N
PUBLISHED CRtrtHA
FRESH FRESH SALTWATER SALTWATER
CRITERION CRITERION CRITERION CRITERION
MAMMUM CONTINUOUS MAXIMUM CONTMUOUS WATER ft ORGANISMS
CONCENTRATION CONCENTRATION CONCENTRATION CONCENTRATION ORGANISMS ONLY

•130. "5.3 0.0037 0.0641

•100. *0.34


3.9+ 1.1+ 43. 9.3 10.

•35,200. *50,000. 0.4 6.94
2.4 0.0043 0.09 0.004 0.00046 0.00048
860,000. 230,000.
•250. '50. *160. *129.
•1,600. *7.5
19. 11. 13. 7.5
•238,000.
488.

•28,900. *1,240. 0.19 15.7
•4,380.
•29,700.
•30.
10.
100.
0.083 0.041 0.011 0.0056
16. 11. 1,100. 50. 50.
1,700.+ 210.+ *10,300. 170,000. 3,433,000.
RECALCULATED VALUES
USMGIRB,ASOF»fM CRITERIA
FEDERAL
WATER* ORGAMSMS DRMKMO REGISTER
ORGANISMS ONLY WATER Ma NOTCE
0.0028 0.0311 57 FR 60913
4.0 57 FR 60848
4 mrem —
45 FR 79335
4.3 360. 100. fTTHM) 57 FR 60911
3,000. 5,200. 57 FR 60890
5.0 57 FR 60848
40. —
0.25 4.4 5.0 57 FR 60911
0.00057 0.00059 2.0 45 FR 79327
. 53 FR 19028
488. 45 FR 79327
1,700. 4,300. 57 FR 60890
50 FR 30788
45 FR 79330
680. 21,000. 100. 57 FR 60911
0.41 34. 100. (TTHM) 57 FR 60911
5.7 470. 100. (TTHM) 57 FR 60911
120. 400. 57 FR 60890
45 FR 79329
45 FR 79329
50. RB
70. RB
51 FR 43666
100. (ToialCr) 50 FR 30788
670,000. 100. (ToialCr) 50 FR 60848

-------

CHRYSENE
COLOR
COPPER
CYANIDE
DDT
DDT METABOLITE
(ODD) (TDE)
DDT METABOLITE
(DDE)
DEMETON
DIBENZO(A,H)
ANTHRACENE
DIBROMOCHLORO-
PROPANE (DBCP)
DI-N-BUTYL PHTHALATE
DICHLOROBENZENE, 1,2-
DICHLOROBENZENE, 1,3-
DICHLOROBENZENE, 1,4-
DICHLOROBENZENES
DICHLOROBENZIDINE, 3,3-
DICHLOROBROMO-
METHANE
DICHLOROETHANE, 1,2-
DICHLOROETHYLENES
DICHLOROETHYLENE, 1,1-
DICHLOROETHYLENE,
cis-1,2-
DICHLOROETHYLENE,
trans, 1,2-
DICHLOROPHENOL, 2,4-
DICHLOROPROPANE
DICHLOROPROPANE, 1,2-
DICHLOROPROPENE
DICHLOROPROPYLENE, 1,3-
DIELDRIN
DIETHYL PHTHALATE
CASI
218-01-9
—
7440-50-8
57-12-5
50-29-3
72-54-8
72-55-9
8065-48-3
53-70-3
96-12-8
84-74-2
95-50-1
541-73-1
106-46-7
25321-22-6
91-94-1
75-27-4
107-06-2
25323-30-3
75-35-4

156-60-5
120-83-2
26638-19-7
78-87-5
26952-23-8
542-75-6
60-57-1
84-66-2
IPKORFTY
POLLUTANT
Y
N
Y
Y
Y
Y
Y
N
Y
N
Y
Y
Y
Y
N
Y
Y
Y
N
Y
N
Y
Y
N
Y
N
Y
Y
Y
HUMAN HEALTH (1M RISK LEVEL FOR CARCINOGENS)
X JPUBUSHEOCRTTERA I RECALCULATED VALUES 1
0 FRESH FRESH SALTWATER SALTWATER I USMGWS.ASOFM/K CRITERIA
5 CRITERION CRITERION CRITERION CRITERION | 1 | FEDERAL
9 MAXMUM CONTINUOUS MAXIMUM CONTINUOUS WATER! ORGAWSMS WATER* ORGANBMS DRMXMG REGBTER
3 CONCENTRATION CONCENTRATION CONCENTRATION CONCENTRATION ORGAWSMS ONLY ORGAWSMS ONLY WATER MCL NOTICE
Y 0.0028 0.0311 57 FR 60913
N NARRATIVE STATEMENT — SEE DOCUMENT RB
N 18.+ 12.+ 2.9 1,300. /a/1300. 50 FR 30789
N 22. 5.2 1.0 200. 700. 220,000. 200. 57 FR 60911
Y 1.1 0.001 0.13 0.001 0.000024 0.000024 0.00059 0.00059 57 FR 60914
Y *0.6 '3.6 0.00083 0.00084 57 FR 60914
Y *1,050. "14. 0.00059 0.00059 57 FR 60914
N 0.1 0.1 RB
Y 0.0028 0.0311 57 FR 60913
Y 0.2 —
N 34,000. 154,000. 2,700. 12,000. 57 FR 6091 3
N 2,700. 17,000. 600. 57 FR 6091 3
N 400. 2,600. 600. 57 FR 6091 3
N 400. 2,600. 75. 57 FR 6091 3
N '1,120. '763. »1,970. 400. 2,600. 45 FR 79328
Y 0.0103 0.0204 0.04 0.077 57 FR 6091 3
Y 0.27 22. 100.
-------
CAS* gf
DIMETHYL PHENOL, 2,4-
DIMETHYL PHTHALATE
DINITROPHENOL, 2,4-
DINITROPHENOL
DINITROTOLUENE, 2,4-
DINITRO-O-CRESOL, 2,4-"
DIOXIN (2,3,7,8 -TCDD)
DIPHENYLHYDRAZINE, 1,2-
DI-2-ETHYLHEXYL
PHTHALATE
ENDOSULFAN
ENDOSULFAN SULFATE
ENDOSULFAN-ALPHA
ENDOSULFAN-BETA
ENDRIN
ENDR1N ALDEHYDE
ETHER, BIS
(2-CHLOROETHYL)
ETHER, BIS
(2-CHLOROISOPROPYL)
ETHER, BIS
(CHLOROMETHYL)
ETHYLBENZENE
ETHYLENE DIBROMIDE
FLUORANTHENE
FLUORENE
GASES, TOTAL DISSOLVED
GROSS ALPHA
PARTICLE ACTIVITY
GUTHION
HALOETHERS
HALOMETHANES
HEPTACHLOR
HEPTACHLOR EPOXIDE
HEXACHLOROBENZENE
HEXACHLOROBLTADIENE
105-67-9
131-11-3
51-28-5
25550-58-7
121-14-2
534-52-1
1746-01-6
122-66-7
117-81-7
115-29-7
1031-07-8
959-98-8
33213-65-9
72-20-8
7421-93-4
111-44-4
108-60-1
542-88-1
100-41-4
106-93-4
206-44-0
86-73-7
—

86-50-0
—
—
76-44-8
1024-57-3
118-74-1
87-68-3
Y
Y
Y
Y
Y
Y
Y
Y
Y
N
Y
Y
Y
Y
Y
Y
Y
N
Y
N
Y
Y
N
N
N
N
N
Y
Y
Y
Y
HUMAN HEALTH (1 W RISK LEVEL FOR CARCINOGENS)
1
N
N
N
N
Y
N
Y
Y
Y
N
N
N
N
N
N
Y
N
Y
N
Y
N
Y
N
Y
N
N
Y
Y
Y
Y
Y
FRESH
CRITERION
MAXMUM
CONCENTRATION
*2,120.



•330.

* <0.01
•270.
•2,000.
0.22

0.22
0.22
0.18




•32,000.

•3,980

FRESH SALTWATER SALTWATER
CRITERION CRITERION CRITERION
CONTINUOUS MAXIMUM CONTMUOUS
CONCENTRATDN CONCENTRATION CONCENTRATION




•230. *590.

• 
-------
CASI is
HEXACHLOROCYCLO-
HEXANE (LINDANE)
HEXACHLOROCYCLO-
HEXANE —ALPHA
HEXACHLOROCYCLO-
HEXANE — BETA
HEXACHLOROCYCLO-
HEXANE — GAMMA
HEXACHLOROCYCLO-
HEXANE —TECHNICAL
HEXACHLOROCYCLO-
PENTADIENE
HEXACHLOROETHANE
INDENO(1,2,3-CD)PYRENE
IRON
ISOPHORONE
LEAD
MALATHION
MANGANESE
MERCURY
METHOXYCHLOR
METHYL BROMIDE
METHYL CHLORIDE
METHYLENE CHLORIDE
MIREX
NAPHTHALENE
NICKEL
NITRATES
NITRITE
NITROBENZENE
NITROPHENOLS
NITROSAMINES
NITROSODIBUTYLAMINE, N-
NITROSODIETHYLAMINE, N-
NITROSODIMETHYLAM1NE,
N-
58-89-9
319-84-6
319-85-7
58-89-9
319-86-8
77-47-4
67-72-1
193-39-5
7439-89-6
78-59-1
7439-92-1
121-75-5
7439-96-5
7439-97-6
72-43-5
74-83-9
74-87-3
75-09-2
2385-85-5
91-20-3
7440-02-0
14797-55-8
—
98-95-3
—
35576-91-1
924-16-3
55-18-5
62-75-9
Y
Y
Y
Y
N
Y
Y
Y
N
Y
Y
N
N
Y
N
Y
Y
Y
N
Y
Y
N
N
Y
Y
Y
N
N
Y
HUMAN HEALTH (104 RISK LEVEL FOR CARCINOGENS)
a
\
«.
Y
Y
Y
Y
Y
N
Y
Y
N
N
N
N
N
N
N
N
Y
Y
N
N
N
N
N
N
N
Y
Y
Y
Y
FRESH
CRITERION
MAXMUU
CONCENTRATION
2.0


2.0

•7.0
•980.


•117,000.
82.+


2.4





•2,300.
1,400.+


•27,000.
•230.
•5,850.



PUBLISHED CWTEM
FRESH SALTWATER SALTWATER
CRITERION CRITERION CRITERION
CONTMUOUS MAXIMUM CONTINUOUS WATER* ORGAWSMS
CONCENTRATION CONCENTRATION CONCENTRATION ORGANISMS ONLY
0.08 0.16 0.0186 0.0625
0.0092 0.031
0.0163 0.0547
0.08 0.16 0.0186 0.0625
0.0123 0.0414
•5.2 *7.0 206.
•540. *940. 1.9 8.74

1,000. 300.
•12,900. 5,200. 520,000.
3.2+ 220. 8.5 50.
0.1 0.1
50. 100.
0.012 2.1 0.025 0.144 0.146
0.03 0.03 100.



0.001 0.001
•620. *2,350.
160.+ 75. 8.3 13.4 100.
10,000.

•6,680. 19,800.
•150. M.SSO.
•3,300,000
0.0064 0.587
0.0008ng/L 0.0012
0.0014 16.
RECALCULATED VALUES
USKGWS.ASOM2/M CRITERIA
FEDERAL
WATER* ORGANBMS DRMKMG REGISTER
ORGANISMS ONLY WATER MCL NOTICE
0.019 0.063 0.2 45 FR 79335
0.0039 0.013 57 FR 6091 4
0.014 0.046 57 FR 60914
0.019 0.063 57 FR 60914
45 FR 79335
240. 17,000. 57 FR 60914
1.9 8.9 57 FR 6091 4
0.0028 0.0311 57 FR 60914
RB
8.4 600. 57 FR 60914
57 FR 60914
RB
RB
0.14 0.15 2.0 50 FR 30791
40. RB
48. 4,000. 57 FR 60912
57 FR 60848
4.7 1,600. 57 FR 60912
RB
45 FR 79337
610. 4,600. 100. 57 FR 60911
10,000. RB
1,000. —
17. 1,900. 57 FR 60914
45 FR 79337
45 FR 79337
45 FR 79338
45 FR 79338
0.00069 8.1 57 FR 60914

-------
HUMAN HEALTH <1M RISK LEVEL FOR CARCINOGENS)

NITROSODIPHENYLAMINE,
N-
NITROSOPYROLIDINE, N-
N-NITROSODI-N-
PROPYLAMINE
OIL AND GREASE
OXYGEN, DISSOLVED
PARATHION
PCBs
PCB-1016
PCB-1221
PCB-1232
PCB-1242
PCB-1248
PCB-1254
PCB-1260
PENTACHLOROETHANE
PENTACHLOROBENZENE
PENTACHLOROPHENOL
PH
PHENANTHRENE
PHENOL
PHOSPHORUS ELEMENTAL
PHTHALATE ESTERS
POLYNUCLEAR AROMATIC
HYDROCARBONS
PYRENE
RADIUM 226/228
SELENIUM
SILVER
SOLIDS DISSOLVED
AND SALINITY
SOLIDS SUSPENDED AND
TURBIDITY
STYRENE
CASI
86-30-6
930-55-2
621-64-7
—
7782-44-7
56-38-2
1336-36-3
12674-11-2
11104-28-2
11141-16-5
5346-92-19
12672-29-6
11097-69-1
11096-82-5
76-01-7
608-93-5
87-86-5
—
85-01-8
108-95-2
7723-14-0
—

129-00-0
—
7782-49-2
7440-22-4


100-42-5
PWOWTT
POLLUTANT
Y
N
Y
N
N
N
Y
Y
Y
Y
Y
Y
Y
Y
N
N
Y
N
Y
Y
N
Y
Y
Y
N
Y
Y
N
N
N
3 PUBLISHED CRITERA
g FRESH FRESH SALTWATER SALTWATER
1 CRITERION CRTTERION CRITERION CRITERION
S MAXNUM CONTINUOUS MAXIMUM CONTMUOUS WATER 1
3 CONCENTRATON CONCENTRATION CONCENTRATION CONCENTRATION ORGANISMS
Y
Y
Y
N
N
N
Y
Y
Y
Y
Y
Y
Y
Y
N
N
N
N
Y
N
N
N
Y
Y
Y
N
N
N
N
Y
4.9
0.016

NARRATIVE STATEMENT — SEE DOCUMENT
RECALCULATED VALUES 1
USMG«B,ASOF»/92 1
ORGANISMS WATER* ORGAWSMS DRMKMG
ONLY ORGAWSMS ONLY WATER MCL
16.1 5.0
91.9
0.005

16.

1.4

WARMWATER AND COLDWATER CRITERIA MATRIX — SEE DOCUMENT
0.065 0.013
2.0 0.014 10. 0.03 0.000079
0.014 0.03
0.014 0.03
0.014 0.03
0.014 0.03
0.014 0.03
0.014 0.03
0.014 0.03
•7,240. "1,100. "390. "281.
74.
...20. «.13 13 79 10io.
6.5-9 6.5-8.5 5-9
/p/30 /p/6.3 /p/7.7 /p/4.6
"10,200. *2,560. "5,800. 3,500.
0.1

"300. 0.0028


20. 5.0 300. 71. 10.
4.H/p/0.92 /p/0.12 2.3/p/7.2 /p/0.92
250,000.
NARRATIVE STATEMENT — SEE DOCUMENT


0.000079
0.000044
0.000044
0.000044
0.000044
0.000044
0.000044
0.000044

85.
0.28


21,000.


.0311
960.


50.




0.5
0.000045
0.000045
0.000045
0.000045
0.000045
0.000045
0.000045


8.2 1.0


4,600,000.



11,000.
20pCi/L
50.



100.
CRITERIA
FEDERAL
REGISTER
NOTCE
57 FR 60914
45 FR 79338
57 FR 60890
RB
51 FR 22978
51 FR 43667
45 FR 79339
57 FR 6091 5
57 FR 60915
57 FR 6091 5
57 FR 6091 5
57 FR 60915
57 FR 6091 5
57 FR 6091 5
45 FR 79328
45 FR 79327
57 FR 60912
RB
57 FR 60848
57 FR 60912
RB

45 FR 79339
57 FR 60914
—
57 FR 60911
57 FR 60911
RB
RB
—

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CAS* &$
SULFIDE-HYDROGEN
SULFIDE 7783-06-4 N
TEMPERATURE — N
TETRACHLOROBENZENE,
1,2,4,5- 95-94-3 N
TETRACHLOROETHANE,
1,1,2,2- 79-34-5 Y
TETRACHLOROETHANES 25322-20-7 Y
TETRACHLOROETHYLENE 127-18-4 Y
TETRACHLOROPHENOL,
2,3,5,6- 935-95-5 N
THALLIUM 7440-28-0 Y
TOLUENE 108-88-3 Y
TOXAPHENE 8001-35-2 Y
TRICHLORINATED ETHANES 25323-89-1 Y
TRICHLOROETHANE, 1,1,1- 71-55-6 Y
TR1CHLOROETHANE, 1,1,2- 79-00-5 Y
TRICHLOROETHYLENE 79-01-6 Y
TRICHLOROPHENOL, 2,4,5- 95-95-4 N
TR1CHLOROPHENOL, 2,4,6- 88-06-2 Y
VINYL CHLORIDE 75-01-4 Y
XYLENES — N
ZINC 7440-66-6 Y
HUMAN HEALTH (1»4 RISK LEVEL FOR CARCINOGENS)
§ FRESH FRESH SALTWATER SALTWATER
X CRITERION CRITERION CRITERION CRITERION
2 MAXMUy CONTINUOUS MAXIMUM CONTINUOUS
3 CONCENTRATION CONCENTRATION CONCENTRATION CONCENTRATION
N
2.0

N SPECIES DEPENDENT CRITERIA
N
Y
N *9,320
Y "5,280.
N
N *1,400.
N '17,500.
Y 0.73
Y *18,000.
N
Y
Y *45,000.
N /p/100
Y
Y
N
N 120.+

•2,400.

•840.

•40.

0.0002


*9,400.
*21,900.
/p/63
*970.


110.+

*9,020.

•10,200.
•440.
•2,130.
•6,300.
0.21

•31,200.

•2,000.
/p/240



95.
2.0
PUBUSHEDCRITERA
WATER » ORGAWSHS
ORGAWSMS ONLY


RECALCULATED VALUES
USMGMS.ASOFU/H
WATER* ORGANISMS
ORGANSMS ONLY

— SEE DOCUMENT



•450.


•5,000.
0.0002




/p/11



86.
38.
0.17

0.8

13.
14,300.
0.00071

18,400.
0.6
2.7
2,600.
1.2
2.0


48.
10.7

8.85

48.
424,000.
0.00073

1,030,000.
41.8
80.7

3.6
525.



0.17 11.



1.7 6.3
6,800. 200,000.
0.00073 0.00075


0.60 42.
2.7 81.

2.1 6.5



CRITERIA
FEDERAL
DRMKMG REGISTER
WATER MCL NOTICE
RB
RB
45 FR 79327
57 FR 6091 2
45 FR 79328
5.0 45 FR 79340
45 FR 79329
2.0 57 FR 6091 3
1,000. 57 FR 6091 2
/p/3.0 57 FR 60915
45 FR 79328
200. 57 FR 60848
5.0 57 FR 60912
5.0 45 FR 79341
45 FR 79329
57 FR 60912
2.0 45 FR 79341
10,000. —
52 FR 6214
+ = Hardness dependent criteria (100 mg/L CaCOs used) RB = Red Book
*= Insufficient data to develop criteria. Value presented is the L.O.E.L. (Lowest Observed Effect Level) /p/ = Proposed criterion
** = The preferred chemical name for 2,4-Dinitro-o-cresol listed in 45 FR 79333 is 4,6 - Dinitro-o-cresol /a/ = Action level
***= pH dependent criteria (7.8 pH used) Y = Yes
MCL = Maximum contaminant level (only for listed chemicals) N = No
TTHM = Total Trihalomethanes Saltwater criteria for lead reflect values updated after 1984.
Note: This chart is for general information. Please use criteria documents or detailed summaries in Quality Criteria for Water 1994 for regulatory purposes.

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            CONTENTS
PREFACE	iii
Water Quality Criteria Summary Concentrations	v
ACENAPHTHENE	1
ACROLEIN	3
ACRYLONITRILE	5
AESTHETIC QUALITIES*	7
ALDRIN	9
ALKALINITY	11
ALUMINUM	13
AMMONIA  	15
ANTIMONY	25
ARSENIC	27
ASBESTOS	31
BACTERIA	33
BARIUM	35
BENZENE	  . 37
BENZIDINE	39
BERYLLIUM	41
BENZENE HEXACHLORIDE (BHC)	43
   (See also: Hexachlorocyclohexane)
   Bis(2-chloroethyl) ether-see: Chloroaltyl Ethers
   Bis(2-chloroisopropyl) ether-see: Chloroaltyl Ethers
   Bis(chloromethyl) ether-see: Chloroaltyl Ethers
BORON*	45
CADMIUM	47
CARBON TETRACHLORIDE	49
CHLORDANE	51
CHLORIDE	53
CHLORINATED BENZENES	55
CHLORINATED ETHANES	57
CHLORINATED NAPHTHALENES	59
CHLORINATED PHENOLS  .  .  .	61
CHLORINE  	65
CHLOROALKYL ETHERS	67
   Chlorobenzene-see: Chlorinated Benzenes
CHLOROFORM	69
 *Entry not listed on 1990 Water Quality Chart.
                                                    xiii

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                 2-CHLOROPHENOL	   71
                   4-Chlorophenol-see: Chlorinated Phenols
                   4-Chlorophenol, 3-methyl-see: Chlorinated Phenols
                 CHLOROPHENOXY HERBICIDES	   73
                 CHLORPYRIFOS  	   75
                 CHROMIUM	   77
                 COLOR	   81
                 COPPER	   83
                 CYANIDE	   85
                 DDT AND METABOLITES	   87
                 DEMETON	   89
                   Dibutyl phthalate-see: Phthalate Esters
                 DICHLOROBENZENES	   91
                 DICHLOROBENZIDINE	   93
                   1,2-Dichloroethane-see: Chlorinated Ethanes
                 DICHLOROETHYLENES	   95
                 2,4-DICHLOROPHENOL	   97
                 DICHLOROPROPANE/ DICHLOROPROPENE	   99
                 DIELDRIN	101
                   Diethyl phthalate-see: Phthalate Esters
                 2,4-DIMETHYLPHENOL	103
                   Dimethyl phthlate-see: Phthalate Esters
                   Dinitrophenol-see: Nitrophenols
                 DINITROTOLUENE	105
                   Dinitro-o-cresol-see.-M'frop/zeno/s
                   Dioxin-see: Tetrachlorodibenzo-p-dioxin
                 DIPHENYLHYDRAZINE   	107
                 DI-2-ETHYLHEXYL PHTHALATE	109
                   (See also: Phthalate Esters)
                 DISSOLVED OXYGEN	Ill
                 DISSOLVED SOLIDS AND SALINITY	117
                 ENDOSULFAN	119
                 ENDRIN	  121
                   Ether, bis(2-chloroethyl)-see: Chloroalkyl Ethers
                   Ether, bis(2-chloroisopropyl)-see: Chloroalkyl Ethers
                   Ether, bis(chloromethyl)-see: Chloroalkyl Ethers
                 ETHYLBENZENE	  .  123
                 FLUORANTHENE	125
                 GASES, TOTAL DISSOLVED	127
                 GUTHION	129
                 HALOETHERS	131
XIV

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HALOMETHANES	133
HARDNESS*	135
HEPTACHLOR	137
HEXACHLOROBENZENE	139
   See also: Chlorinated Benzenes
HEXACHLOROBUTADIENE	141
HEXACHLOROCYCLOHEXANE	143
   (Note: gamma-hexachlorocyclohexane = Lindane-see also: BHC)
HEXACHLOROCYCLOPENTADIENE	145
   Hexachloroethane-see: Chlorinated Ethanes
   Hydrogen sulfide-see: Sulfide-faS
IRON	147
ISOPHORONE	151
LEAD	153
MALATHION	155
   Lindane-see; Hexachlorocyclohexane
MANGANESE	157
MERCURY	159
METHOXYCHLOR	163
MIREX	165
NAPHTHALENE	167
NICKEL	179
NITRATES/NITRITES	171
NITROBENZENE	173
NITROPHENOLS	175
NITROSAMINES	177
   N-Nitrosodibutylamine-see.-Nifrosammes
   N-Nitrosodiethylamine-see:Nffrosflmines
   N-Nitrosodimethylamine-see: Nitrosamines
   N-Nitrosodiphenylamine-see.-Mfrosammes
   N-Nitrosodipropylamine-see:Mfrosamines
   N-Nitrosopyrolidine-see:AWrosflmznes
OIL AND GREASE  	179
   Oxygen, Dissolved-see: Dissolved Oxygen
PARATHION	183
   PCBs-see: Polychlorinated Biphenyls
   Pentachloroethane-see: Chlorinated Ethanes
   Pentachlorobenzene-see: Chlorinated Benzenes
PENTACHLOROPHENOL(PCP)	185
pH	187
PHENOL	189
                                                        XV

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                PHOSPHORUS	191
                PHTHALATE ESTERS	195
                POLYCHLORINATED BIPHENYLS (PCBs)	197
                POLYNUCLEAR AROMATIC HYDROCARBONS	199
                SELENIUM	201
                SILVER	203
                   Solids, Dissolved and Salinity-see: Dissolved Solids
                SOLIDS (SUSPENDED, SETTLEABLE) AND TURBIDITY	205
                SULFIDE - HYDROGEN SULFIDE	207
                TAINTING SUBSTANCES*	209
                TEMPERATURE	211
                   Tetrachlorobenzenes-see: Chlorinated Benzenes
                 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN
                (TCDD) PIOXIN)	221
                   Tetrachloroethanes-see: Chlorinated Ethanes
                TETRACHLOROETHYLENE	223
                   Tetrachlorophenol-see: Chlorinated Phenols
                THALLIUM	225
                TOLUENE  	227
                TOXAPHENE	229
                   Trichlorinated Ethanes-see: Chlorinated Ethanes
                TRICHLOROETHYLENE	231
                   Trichlorophenols-see: Chlorinated Phenols
                VINYL CHLORIDE	233
                ZINC	235
                Appendix A: Derivation of the 1985 Aquatic Life Criteria   	237
                Appendix B: Derivation of the 1980 Aquatic Life Criteria .......  255
                Appendix C: Derivation of the 1980 Human Health Criteria	267
                Appendix D: Derivation of 1976 Philosophy of Aquatic Life Criteria .  283
                Appendix E: Bioconcentration Factors	287
                Appendix F: Water Quality Criteria Documents	291
XVI

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                           ACENAPHTHENE
                                   CAS# 83-32-9
CRITERIA

Aquatic Life
Human Health
The available data for acenaphthene indicate that acute toxicity to fresh-
water aquatic life occurs at concentrations as low as 1,700 ng/L and would
occur at lower concentrations among species that are more sensitive than
those tested. No data are available concerning the chronic toxicity of ace-
naphthene  to  sensitive  freshwater  aquatic  animals, but toxicity  to
freshwater algae occurs at concentrations as low as 520 ng/L.
   The available data for acenaphthene indicate that acute and  chronic
toxicity to saltwater aquatic life occurs at concentrations as low as 970 and
710 ng/L, respectively, and would occur at lower  concentrations among
species that are more sensitive than those tested. Toxicity to algae occurs at
concentrations as low as 500 ng/L.

Human health  criteria were  recalculated using Integrated  Risk Informa-
tion  System (IRIS) to reflect available data as of  12/92 (57 F.R.  60890).
Recalculated IRIS values for acenaphthene  are 1,200 (ig/L for ingestion of
contaminated water and organisms and 2,700 ng/L for ingestion  of con-
taminated aquatic organisms only.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60890, December 22,1993)
                   See Appendix C for Human Health Methodology.

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                                 ACROLEIN
                                  CAS# 107-02-8
CRITERIA

Aquatic Life
Human Health
The available data for acrolein indicate that acute and chronic toxicity to
freshwater aquatic life occurs at concentrations as low as 68 and 21 ng/L,
respectively, and would occur at lower concentrations among species that
are more sensitive than those tested.
   The available data for acrolein indicate that acute toxicity to saltwater
aquatic life occurs at concentrations as low as 55 (ig/L and would occur at
lower concentrations among species that are more sensitive than  those
tested. No data are available concerning the chronic toxicity of acrolein to
sensitive saltwater aquatic life.

For the protection of human health from the toxic properties of acrolein in-
gested through water and contaminated aquatic  organisms, the ambient
water criterion is 320 |xg/L.
   For  the protection of human health from  the toxic properties  of
acrolein ingested through contaminated aquatic organisms alone, the am-
bient water criterion is 780 ug/L.
                   (45 F.R. 79318, November 28,1980)
                   See Appendix C for Human Health Methodology.

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                            ACRYLONITRILE
                                   CAS# 107-13-1
CRITERIA

Aquatic Life
Human Health
The available data for acrylonitrile indicate that acute toxicity to freshwa-
ter aquatic life occurs at concentrations as low as 7,550 ng/L and would
occur at lower concentrations among species that are more sensitive than
those tested. No definitive data are available concerning the chronic toxic-
ity of acrylonitrile to sensitive freshwater aquatic life, but mortality occurs
at concentrations as low as 2,600 ng/L, with a fish species exposed for 30
days.
   Only one saltwater species has been tested with acrylonitrile, therefore
no statement can be made concerning acute or chronic toxicity.

For the maximum protection of human health from  the potential carcino-
genic effects resulting from exposure to acrylonitrile through ingestion of
contaminated water and contaminated aquatic  organisms, the ambient
water concentrations should be zero, based on the nonthreshold assump-
tion  for this chemical. However, zero level may not be attainable at  the
present time. Therefore, the levels that may result in incremental increase
of cancer risk over the lifetime are estimated at 10", 10 , and 10" .
   Published human health criteria were recalculated using Integrated
Risk Information System (IRIS) to reflect available data as of 12/92. Recal-
culated  IRIS values for acrylonitrile are 0.059 ng/L for ingestion of
contaminated water and organisms and 0.66 jig/L  for ingestion of con-
taminated aquatic organisms only. IRIS values are based on a 10   risk level
for carcinogens.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60848, December 22,1992)
                   See Appendix C for Human Health Methodology.

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                     AESTHETIC  QUALITIES
CRITERIA
                  All waters free from substances attributable to wastewater or other dis-
                  charges that

                     1.  settle to form objectionable deposits;

                     2.  float as debris, scum, oil, or other matter to form nuisances;

                     3.  produce objectionable color, odor, taste, or turbidity;

                     4.  injure or are toxic or produce adverse physiological responses in
                        humans, animals, or plants; and

                     5.  produce undesirable or nuisance aquatic life.
                  (Quality Criteria for Water, July 1976) PB-263943
                  See Appendix D for Methodology.

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8

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                                    *ALDRIN
                                    CAS# 309-00-2
CRITERIA

Aquatic Life
Human Health
Not to exceed 3.0 ng/L in fresh water or 1.3 ^ig/L in salt water.
   For freshwater aquatic life, the concentration of aldrin should not ex-
ceed 3.0 ng/L at any time. No data are available concerning the chronic
toxicity of aldrin to sensitive freshwater aquatic life.
   For saltwater aquatic life, the concentration of aldrin  should not ex-
ceed 1.3 ng/L at any time. No data are available concerning the chronic
toxicity of aldrin to sensitive saltwater aquatic life.

For the maximum protection of human health from the potential carcino-
genic effects  of exposure to  aldrin through ingestion  of contaminated
water and contaminated aquatic organisms, the ambient water concentra-
tion  should be zero,  based  on  the nonthreshold assumption  for this
chemical. However,  zero level may not be attainable at  the present time.
Therefore, the levels that may result in incremental increase of cancer risk
over the lifetime are estimated at 10"5, 10"6, and 10"7.
   Human health criteria were recalculated using Integrated Risk Infor-
mation System (IRIS) to reflect available data as of 12/92 (57 F.R. 60848,
December 22, 1992). Recalculated IRIS values for aldrin  are 0.00013 ng/L
for ingestion of contaminated water and organisms and 0.00014 ng/L for
ingestion of contaminated aquatic organisms only. IRIS  values are based
on a  10"6 risk level for carcinogens.
                    (45 F.R. 79318, November 28,1980) (57 F.R. 60848, December 22,1992)
                    See Appendix B for Aquatic Life Methodology.
                    See Appendix C for Human Health Methodology.

                    •Indicates suspended, canceled, or restricted by U.S. EPA Office of Pesticides and Toxic
                     Substances

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10

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CRITERIA
                                ALKALINITY
                   20 mg/L, or more as CaCO^ for freshwater aquatic life except where natu-
                   ral concentrations are less.
Introduction
Rationale
Expressed commonly as milligrams per liter of calcium carbonate, alkalin-
ity is the sum total of components in the water that tend to elevate the pH
of the water above a value of about 4.5. It is measured by titration with
standardized acid to a pH value of about 4.5. Alkalinity, therefore, is a
measure of water's buffering capacity, and since pH has a direct effect on
organisms as well as an indirect effect on the toxicity of certain other pol-
lutants in the water, the buffering capacity is important to water quality.
Examples of commonly occurring materials in natural waters that increase
the alkalinity are carbonates, bicarbonates, phosphates, and hydroxides.

The alkalinity of water used for municipal water supplies is important
because it affects the amount of chemicals that need to be added  to ac-
complish coagulation, softening, and control of corrosion in distribution
systems. The alkalinity of water assists in the neutralization of excess
acid produced during the addition of such materials as aluminum sul-
fate during chemical coagulation. Waters having sufficient alkalinity do
not have to be supplemented with artificially added materials  to in-
crease  the alkalinity. Alkalinity resulting from naturally  occurring
materials such as carbonate and bicarbonate is not considered a health
hazard  in drinking water  supplies, per se,  and naturally occurring
maximum levels up to approximately 400 mg/L as calcium carbonate
are not considered  a problem to human health.
   Alkalinity is important for fish and other aquatic life in freshwater sys-
tems because it buffers pH changes that occur naturally as a result of
photosynthetic activity of the chlorophyll-bearing vegetation. Compo-
nents of alkalinity such as carbonate and bicarbonate will complex some
toxic heavy metals  and reduce their toxicity markedly. For these reasons,
in 1968 the National Technical Advisory Committee recommended a mini-
mum alkalinity of 20 mg/L. The subsequent 1974 National Academy of
Sciences (NAS) report recommended that natural alkalinity not be reduced
by more than 25 percent but did not place an absolute minimal value for it.
The use of the 25 percent reduction avoids the problem of establishing
standards on waters where natural alkalinity is at or below 20 mg/L.  For
such waters, alkalinity should not be further reduced.
   The NAS Report recommends that adequate amounts of alkalinity be
maintained to buffer the pH within tolerable limits for marine waters. It
has been noted as a correlation that  productive waterfowl habitats  are
above 25 mg/L with higher alkalinities resulting in better waterfowl habi-
tats.
   Excessive alkalinity can cause problems for swimmers by altering the
pH of the lacrimal fluid around the eye, causing irritation.
                                                                                  11

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                        For industrial water supplies high alkalinity can be damaging to indus-
                    tries involved in food production, especially those in which acidity accounts
                    for flavor and stability, such as the carbonated beverages. In other instances,
                    alkalinity is desirable because water with a high alkalinity is much less corro-
                    sive.
                        A brief summary of maximum alkalinities accepted as a source of raw
                    water by industry is included in Table 1. The concentrations listed in the
                    table are for water prior to treatment and thus are only desirable ranges
                    and not critical ranges for industrial use.
                    Table 1.*—Maximum alkalinity in waters used as a source of supply prior to
                    treatment.
INDUSTRY
Steam generation boiler makeup
Steam generation cooling ... ...
Textile mill products 	
Paper and allied products . . ...
Chemical and allied products 	
Petroleum refining
Primary metals industries 	
Food canning industries
Bottled and canned soft drinks 	

ALKALINITY
MG/L AS CACO,
350
500
50-200
75-150
500
500
200
300
85

                             Source: National Academy of Sciences (1974).

                        The effect of alkalinity in water used for irrigation may be important in
                    some instances because it may indirectly increase the relative proportion
                    of sodium in soil water. As an example, when bicarbonate concentrations
                    are high, calcium and magnesium ions that are in solution precipitate as
                    carbonates in the soil water as the  water becomes more  concentrated
                    through evaporation and transpiration.  As the calcium and magnesium
                    ions decrease in concentration, the percentage of sodium increases and re-
                    sults in soil and  plant damage. Alkalinity may also lead to chlorosis in
                    plants because it causes the iron to precipitate as a hydroxide. Hydroxyl
                    ions react with available iron in the soil water and make the iron unavail-
                    able to plants. Such deficiencies induce  chlorosis and  further  plant
                    damage. Usually alkalinity must exceed  600 mg/L before such affects are
                    noticed, however.
                    (Quality Criteria for Water, July 1976) PB-263943
                    See Appendix D for Methodology.
12

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CRITERIA
                                 ALUMINUM
                                  CAS# 7429-90-5
Aquatic Life      When the pH is between 6.5 and 9.0, four-day average concentration of
                   aluminum should not exceed 87 ng/L. One-hour average concentration of
                   aluminum should not exceed 750 ng/L for freshwater aquatic life.

Summary         Acute tests have been conducted on aluminum at pH betwen 6.5 and 9.0
                   with freshwater species in 14 genera. In many tests, less than 50 percent of
                   the organisms were affected at the highest concentration tests. Both cerio-
                   daphnids and brook trout were affected at concentrations below 4,000
                   Hg/L, whereas some other fish and invertebrate species were  not affected
                   by 45,000 ng/L. Some researchers found that the acute toxicity of alumi-
                   num increased with pH, whereas others found the opposite to be true.
                      Three studies have been conducted on the chronic  toxicity of alumi-
                   num  to  aquatic  animals.  The  chronic  values  for Daphnia  magna,
                   Ceriodaphnia dubia, and the fathead minnow were 742.2, 1,908, and 3,288
                   (ig/L, respectively. The diatom, Cydotella meneghiniana, and the green alga,
                   Selenastrum capricornutum, were affected by concentrations  of aluminum in
                   the range of 400 to 900 ng/L. Bioconcentration factors from 50 to 231 were
                   obtained in tests with young brook trout. At a pH of 6.5 to 6.6, 169 |ig/L
                   caused a 24 percent reduction in the growth of young brook trout and 174
                   Hg/L killed 58 percent of the exposed striped bass.

National Criteria The procedures described in the "Guidelines for Deriving Numerical Na-
                   tional Water Quality Criteria for the Protection of Aquatic  Organisms and
                   Their Uses" indicate that, except possibly where a locally "important spe-
                   cies is very sensitive, freshwater aquatic organisms and their  uses should
                   not be affected unacceptably, when the  pH is between  6.5 and 9.0, if the
                   four-day average concentration of aluminum does not exceed 87 ug/L
                   more than once every three years on the average and if the one-hour aver-
                   age concentration does  not exeed 750 jig/L more than once every three
                   years on the average.
                   (53 F.R. 33178, August 30,1988)
                   See Appendix A for Aquatic Life Methodology.
                                                                                 13

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14

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                                  AMMONIA
                                   CAS# 7664-41-7
SUMMARY

Fresh Water
All concentrations used herein are  expressed  as  un-ionized ammonia
(NH3) because NH^ not the ammonium ion (NH4+), has been demon-
strated to be the principal toxic form  of ammonia. The data  used in
deriving criteria are predominantly from flow through tests that measured
ammonia concentrations.
    Ammonia was reported to be acutely toxic to freshwater organisms at
concentrations (uncorrected for pH) ranging  from 0.53 to 22.8 mg/L NH3
for 19 invertebrate species representing 14 families and 16 genera and from
0.083 to 4.60 mg/L NH3 for 29 fish species from  9 families and 18 genera.
Among fish species, reported 96-hour LC50 ranged from 0.083 to 1.09
mg/L for salmonids and from 0.14 to 4.60 mg/L NH3 for nonsalmonids.
Reported data from chronic tests on ammonia with  two freshwater inver-
tebrate  species,  both  daphnids,  showed  effects  at  concentrations
(uncorrected for pH) ranging from 0.304 to 1.2 mg/L  NH3  and with 9
freshwater fish species, from 5 families and 7 genera, ranging from 0.0017
to 0.612 mg/LNH3.
    Concentrations of ammonia are acutely toxic to fishes and can cause
loss of equilibrium, hyperexcitability, increased breathing, cardiac output
and oxygen uptake, and, in extreme cases, convulsions, coma, and death.
At lower concentrations, ammonia has many effects on fishes, including a
reduction in hatching success, reduction in growth rate and morphological
development, and pathologic changes in tissues of gills, livers, and kid-
neys.
    Several factors have been shown to modify acute NH3 toxicity in fresh
water. Some factors alter the concentration of un-ionized ammonia in the
water by affecting the aqueous ammonia equilibrium, and some factors af-
fect the toxicity of un-ionized ammonia itself, either by ameliorating or
exacerbating the effects of ammonia. Factors that have been shown to af-
fect ammonia  toxicity   include   dissolved  oxygen  concentration,
temperature, pH, previous acclimation to ammonia, fluctuating  or inter-
mittent exposures, carbon dioxide concentration, salinity, and the presence
of other toxicants.
    The most well-studied of these factors is pH: the acute toxicity of NH3
has been shown to increase as pH decreases. Sufficient data exist from tox-
icity tests conducted at different pH values to formulate a mathematical
expression to describe pH-dependent, acute NH3 toxicity. The very limited
amount of data regarding effects of pH on chronic NH3 toxicity also indi-
cates  increasing NH3 toxicity with decreasing pH, but the  data are
insufficient to derive a broadly applicable toxicity/pH relationship. Data
on temperature effects on  acute NH3 toxicity are limited and somewhat
variable, but indications are that NH3 toxicity to fish is greater as tempera-
ture decreases. No information is available regarding temperature effects
on chronic NH3 toxicity.
                                                                                   15

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                       Examination of pH and temperature-corrected acute NH3 toxicity val-
                   ues  among species and genera of freshwater organisms showed that
                   invertebrates are generally more tolerant than fishes, a notable exception
                   being the fingernail clam. No clear trend exists among groups of fish; the
                   several most sensitive tested species and genera include representatives
                   from diverse families (Salmonidae, Cyprinidae, Percidae, and Centrarchi-
                   dae). Available chronic toxicity data for freshwater organisms also indicate
                   invertebrates (cladocerans, one insect  species) to be more tolerant than
                   fishes, again with the exception of the fingernail clam. When corrected for
                   the presumed effects of temperature and pH, chronic toxicity values also
                   show no clear trend among groups of  fish, the most sensitive species in-
                   cluding  representatives  from   five families  (Salmonidae, Cyprinidae,
                   Ictaluridae, Centrarchidae, and Catostomidae) and having chronic values
                   ranging by not much more than a factor or two. The range of acute-chronic
                   ratios for 10 species from 6 families was 3 to 43; acute-chronic ratios were
                   higher for the species having chronic tolerance below the median.
                       Available data indicate that differences in sensitivities between warm-
                   water  and coldwater families of aquatic organisms are  inadequate to
                   warrant discrimination in the national  ammonia criterion between bodies
                   of water with "warmwater"  and "coldwater" fishes; rather, effects of or-
                   ganism sensitivities on the criterion are most appropriately handled by
                   site-specific criteria derivation procedures.
                       Data for concentrations of NH3 toxic to freshwater phytoplankton and
                   vascular plants, although limited, indicate that freshwater plant species
                   are appreciably more tolerant to NH3 than are invertebrates or fishes. The
                   ammonia criterion appropriate for the protection of aquatic animals, there-
                   fore, will probably sufficiently protect plant life.

Salt Water        In aqueous solutions, the ammonium ion dissociates to un-ionized ammo-
                   nia and the hydrogen ion. The equilibrium equation can be written

                   Equation 1

                              H2O + NH4+  <=>  NH3 + H3O+
                   The total ammonia concentration is the sum of NHs and NH4+.

                       The toxicity of aqueous ammonia solutions to aquatic organisms is pri-
                   marily attributable to the un-ionized form, the ammonium ion being less
                   toxic. It is necessary, therefore, to know the percentage of total ammonia in
                   the un-ionized form in order to establish the corresponding total ammonia
                   concentration toxic to aquatic life.  The  percentage of un-ionized ammonia
                   (UIA) can be calculated from the solution pH and pK^ the negative log of
                   stoichiometric dissociation,

                   Equation 2
                              %UIA=100[1 +  10(pKa'pH)]'1
                   The stoichiometric dissociation constant is defined

                   Equation 3

                                    Kg-

                   where the brackets represent molal concentrations. Ka is a function of the
                   temperature and ionic strength of the solution.


16

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                       Whitfield (1974) developed theoretical models to determine the pKg of
                   the ammonium ion in seawater. He combined his models with the infinite
                   dilution data of Bates and Pinching (1949) to define general equations for
                   the PKa of ammonium ion as a function of salinity and temperature.
                       Whitfield's models allow reasonable approximations of the percent of
                   un-ionized ammonia in sea water and have been substantiated experimen-
                   tally. Hampson's (1977) program for Whitfield's full seawater model has
                   been used to calculate the un-ionized ammonia fraction of measured total
                   ammonia concentrations in toxicity studies conducted by EPA and also in
                   deriving most other acute and chronic ammonia values that contribute to
                   the criteria. The equations for this model are

                   Equation 4
                         % UIA= 100 [1  + 10 (X + 0.0324 (298-T) + 0.0415 P/T - pH)]'1
                   where
                       P =  1 AIM for all toxicity testing reported to date
                       T =  temperature (K)
                       X =  pksa or the stoichiometric acid hydrolysis constant of ammonium
                           ions in saline water based on I,
                   Equations
                                     I = 19.9273 S (1000-1.005109 S)'1
                   where
                       I =  molal ionic strength of the sea water
                       S=  salinity (g/kg)
                       The Hampson program calculates the value for I for the test salinity
                   (Eq. 5), finds the corresponding pk5^ then calculates % UIA (Eq. 4).

                       The major factors influencing the degree of ammonia dissociation are
                   pH and temperature. Both correlate positively with un-ionized ammonia.
                   Salinity, the least influential of the three water quality factors that control
                   the fraction of un-ionized ammonia, is inversely correlated.
NATIONAL CRITERIA

Fresh Water      The procedures described in the "Guidelines for Deriving Numerical Na-
                   tional Water Quality Criteria for the Protection of Aquatic Organisms and
                   Their Uses" indicate that, except possibly where a locally important species is
                   very sensitive, freshwater aquatic organisms and their uses should not be af-
                   fected unacceptably if

                      (1)  the one-hour* average concentration of un-ionized ammonia (in
                          mg/L NH3) (see Tables 1 and 2) does not exceed more often than
                          once every three years on the average the numerical value given by
                          0.52/FT/FPH/2

                          where:

                          FT =    1 o°-03<2°-TCAP>   ; TCAP* Ts 30
                                  10o.03(20-T)      jOsT
                    *An averaging period of one hour may not be appropriate if excursions of
                    concentrations to greater than 1.5 times the average occur during the hour; in such
                    cases, a shorter averaging period may be needed.

                                                                                  17

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Table 1. — One-hour average concentrations for ammonia with salmonids or other
sensitive coldwater species present.*
PH
0
5
Temperature
10
(°C)
15
20
25
30
Un-ionized Ammonia (mg/L NHa)
6.50
6.75
7.00
7.25
7.50
7.75
8.00
8.25
8.50
8.75
9.00
0.0091
0.0149
0.023
0.034
0.045
0.056
0.065
0.065
0.065
0.065
0.065
0.0129
0.021
0.033
0.048
0.064
0.080
0.092
0.092
0.092
0.092
0.092
0.0182
0.030
0.046
0.068
0.091
0.113
0.130
0.130
0.130
0.130
0.130
Total Ammonia
6.50
6.75
7.00
7.25
7.50
7.75
8.00
8.25
8.50
8.75
9.00
*To convert
35
32
28
23
17.4
12.2
8.0
4.5
2.6
1.47
0.86
33
30
26
22
16.3
11.4
7.5
4.2
2.4
1.40
0.83
these values to mg/L N
31
28
25
20
15.5
10.9
7.1
4.1
2.3
1.37
0.83
0.026
0.042
0.066
0.095
0.128
0.159
0.184
0.184
0.184
0.184
0.184
0.036
0.059
0.093
0.135
0.181
0.22
0.26
0.26
0.26
0.26
0.26
0.036
0.059
0.093
0.135
0.181
0.22
0.26
0.26
0.26
0.26
0.26
0.036
0.059
0.093
0.135
0.181
0.22
0.26
0.26
0.26
0.26
0.26
(mg/L NHa)
30
27
24
19.7
14.9
10.5
6.9
4.0
2.3
1.38
0.86
29
27
23
19.2
14.6
10.3
6.8
3.9
2.3
1.42
0.91
20
18.6
16.4
13.4
10.2
7.2
4.8
2.8
1.71
1.07
0.72
14.3
13.2
11.6
9.5
7.3
5.2
3.5
2.1
1.28
0.83
0.58
, multiply by 0.822.
                            FPH =  1
                                          1.25
; 8 £ pH s 9

; 6.5 s pH s 8
                            TCAP = 20°C; salmonids or other sensitive coldwater species present
                            TCAP = 25°C; salmonids and other sensitive coldwater species absent

                       (2)  the four-day average concentration of un-ionized ammonia (in
                            mg/L NH3) (see Tables 3 and 4) does not exceed, more often than
                            once every three years on the average, the average** numerical
                            value given by 0.80/FT/FPH/RATIO, where FT and FPH are as
                            above and
                            RATIO  = 13.5
                                    = 20
                                            10
                                              7.7-pH
                   ;  7.7 s pH s 9

                   ;6.5spHs7.7
                                           1+107.4-pH

                            TCAP = 15°C; salmonids or other sensitive coldwater species present
                            TCAP = 20°C; salmonids and other sensitive coldwater species absent
                     "Because these formulas are nonlinear in pH and temperature, the criterion should be
                      the average of separate evaluations of the formulas reflective of the fluctuations of
                      flow, pH, and temperature within the averaging period; it is not appropriate in
                      general to simply apply the formula to average pH, temperature, and flow.
18

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Table 2. — One-hour average concentrations for ammonia with salmon Ids or other
sensitive coldwater species absent.*
Temperature (°C)
DH
0
5
10
15
20
25
30
Un-ionized Ammonia (mg/L NHa)
6.50
6.75
7.00
7.25
7.50
7.75
8.00
8.25
8.50
8.75
9.00
0.0091
0.0149
0.023
0.034
0.045
0.056
0.065
0.065
0.065
0.065
0.065
0.0129
0.021
0.033
0.048
0.064
0.080
0.092
0.092
0.092
0.092
0.092
0.0182
0.030
0.046
0.068
0.091
0.113
0.130
0.130
0.130
0.130
0.130
Total Ammonia
6.50
6.75
7.00
7.25
7.50
7.75
8.00
8.25
8.50
8.75
9.00
35
32
28
23
17.4
12.2
8.0
4.5
2.6
1.47
0.86
33
30
26
22
16.3
11.4
7.5
4.2
2.4
1.40
0.83
*To convert these values to mg/L N,
31
28
25
20
15.5
10.9
7.1
4.1
2.3
1.37
0.83
multiply by
0.026
0.042
0.066
0.095
0.128
0.159
0.184
0.184
0.184
0.184
0.184
0.036
0.059
0.093
0.135
0.181
0.22
0.26
0.26
0.26
0.26
0.26
0.051
0.084
0.131
0.190
0.26
0.32
0.37
0.37
0.37
0.37
0.37
0.051
0.084
0.131
0.190
0.26
0.32
0.37
0.37
0.37
0.37
0.37
(mg/L NHa)
30
27
24
19.7
14.9
10.5
6.9
4.0
2.3
1.38
0.86
0.822.
29
27
23
19.2
14.6
10.3
6.8
3.9
2.3
1.42
0.91

29
26
23
19.0
14.5
10.2
6.8
4.0
2.4
1.52
1.01

20
18.6
16.4
13.5
10.3
7.3
4.9
2.9
1.81
1.18
0.82

   The extremes for temperature (0°C and 30°C) and pH (6.5, 9) given in
the above formulas are absolute. It is not permissible with current data to
conduct any extrapolations beyond these limits. In particular, there is rea-
son to believe that appropriate criteria at pH >  9 will be lower than the
plateau between pH 8 and 9 given above.
   Limited  data exists on the effect of temperature on chronic toxicity.
EPA will be conducting additional research on the effects of temperature
on ammonia toxicity to fill perceived data gaps. Because of this uncer-
tainty, additional site-specific information should be developed before
these criteria are used in wasteload allocation modeling. For example, the
chronic criteria tabulated for sites lacking salmonids are less certain at
temperatures much below 20°C than those tabulated at temperatures near
20°C.  Where the  treatment levels needed to meet these criteria below
20°C may be substantial, use of site-specific criteria is strongly suggested.
Development of such criteria should be based upon site-specific toxicity
tests.
   The recommended exceedence frequency of three years is the Agency's
best scientific judgment of the average amount of time for an unstressed
system to recover from a  pollution event in which  exposure to ammonia
exceeds the criterion. A stressed system — for example, one in which sev-
eral outfalls  occur in a limited area — would be expected to require more

                                                               19

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Table 3. — Four-day average concentrations for ammonia with salmonlds or other
sensitive coldwater species present.*

DH

0

5
Temperature
10
CO

15 20

25

30
Un-ionized Ammonia (mg/L NHa)
6.50
6.75
7.00
7.25
7.50
7.75
8.00
8.25
8.50
8.75
9.00

6.50
6.75
7.00
7.25
7.50
7.75
8.00
8.25
8.50
8.75
9.00
*To convert
0.0008
0.0014
0.0025
0.0044
0.0018
0.0129
0.0149
0.0149
0.0149
0.0149
0.0149

3.0
3.0
3.0
3.0
3.0
2.8
1.82
1.03
0.58
0.34
0.195
0.0011
0.0020
0.0035
0.0062
0.0111
0.0182
0.021
0.021
0.021
0.021
0.021
Total
2.8
2.8
2.8
2.8
2.8
2.6
1.70
0.97
0.55
0.32
0.189
0.0016
0.0028
0.0049
0.0088
0.0156
0.026
0.030
0.030
0.030
0.030
0.030
Ammonia
2.7
2.7
2.7
2.7
2.7
2.5
1.62
0.93
0.53
0.31
0.189
these values to mg/L N, multiply by
0.0022
0.0039
0.0070
0.0124
0.022
0.036
0.042
0.042
0.042
0.042
0.042
(mg/LNHa)
2.5
2.6
2.6
2.6
2.6
2.4
1.57
0.90
0.53
0.31
0.195
0.822.
0.0022
0.0039
0.0070
0.0124
0.022
0.036
0.042
0.042
0.042
0.042
0.042

1.76
1.76
.76
.77
.78
.66
.10
0.64
0.38
0.23
0.148

0.0022
0.0039
0.0070
0.0124
0.022
0.036
0.042
0.042
0.042
0.042
0.042

1.23
1.23
1.23
1.24
1.25
1.17
0.78
0.46
0.28
0.173
0.116

0.0022
0.0039
0.0070
0.0124
0.022
0.036
0.042
0.042
0.042
0.042
0.042

0.87
0.87
0.87
0.88
0.89
0.84
0.56
0.33
0.21
0.135
0.094

                   time for recovery. The resilience of ecosystems and their ability to recover
                   differ greatly, however, and site-specific criteria may be established if ade-
                   quate justification is provided.
                      The use of criteria in designing waste treatment facilities requires select-
                   ing an  appropriate wasteload allocation  model. Dynamic models are
                   preferred for the application of these criteria. Limited data or other factors
                   may make their use impractical, in which case one should rely on a steady-
                   state model. The Agency recommends the interim use of 1Q5 or 1Q1O for
                   Criterion Maximum Concentration  design flow and 7Q5 or 7Q1O for the
                   Criterion Continuous Concentration design flow in steady-state models for
                   unstressed and  stressed systems, respectively. The Agency acknowledges
                   that the Criterion Continuous Concentration stream flow averaging period
                   used for steady-state wasteload allocation modeling may be as long as 30
                   days in situations involving POTWs designed to remove ammonia where
                   limited variability of effluent pollutant concentration and resultant concen-
                   trations in  receiving waters can be  demonstrated.  In cases where low
                   variability can be demonstrated, longer averaging periods for the ammonia
                   Criterion Continuous Concentration (e.g., 30-day averaging periods) would
                   be acceptable because the magnitude and duration of exceedences above
                   the Criterion Continuous Concentration would  be  sufficiently  limited.
20

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Table 4. — Four-day average concentrations for ammonia with salmonids or other
sensitive coldwater species absent.* **
Temperature (°C)
OH

6.50
6.75
7.00
7.25
7.50
7.75
8.00
8.25
8.50
8.75
9.00

6.50
6.75
7.00
7.25
7.50
7.75
8.00
8.25
8.50
8.75
9.00

0 5 10 15 20

25

30
Un-ionized Ammonia (mg/L NHa)
0.0008 0.0011 0.0016 0.0022
0.0014 0.0020 0.0028 0.0039
0.0025 0.0035 0.0049 0.0070
0.0044 0.0062 0.0088 0.0124
0.0078 0.0111 0.0156 0.022
0.0129 0.0182 0.026 0.036
0.0149 0.021 0.030 0.042
0.0149 0.021 0.030 0.042
0.0149 0.021 0.030 0.042
0.0149 0.021 0.030 0.042
0.0149 0.021 0.030 0.042
0.0031
0.0055
0.0099
0.0175
0.031
0.051
0.059
0.059
0.059
0.059
0.059
0.0031
0.0055
0.0099
0.0175
0.031
0.051
0.059
0.059
0.059
0.059
0.059
0.0031
0.0055
0.0099
0.0175
0.031
0.051
0.059
0.059
0.059
0.059
0.059
Total Ammonia (mg/L NHa)
3.0 2.8 2.7 2.5
3.0 2.8 2.7 2.6
3.0 2.8 2.7 2.6
3.0 2.8 2.7 2.6
3.0 2.8 2.7 2.6
2.8 2.6 2.5 2.4
1.82 1.70 1.62 1.57
1.03 0.97 0.93 0.90
0.58 0.55 0.53 0.53
0.34 0.32 0.31 0.31
0.195 0.189 0.189 0.195
2.5
2.5
2.5
2.5
2.5
2.3
1.55
0.90
0.53
0.32
0.21
.73
.74
.74
.75
.76
.65
.10
0.64
0.39
0.24
0.163
1.23
1.23
1.23
1.24
1.25
1.18
0.79
0.47
0.29
0.190
0.133
"To convert these values to mg/L N, multiply by 0.822.
"These values may be conservative; however, If a more refined criterion Is desired, EPA
recommends a site-specific criteria modification.
Saltwater
These matters .are discussed in more detail in EPA's "Technical Support
Document for Water Quality-Based Toxics Control."

The procedures described in the "Guidelines for Deriving Numerical Na-
tional Water Quality Criteria for the Protection of Aquatic Organisms and
Their Uses" indicate that, except possibly where a locally important species
is very sensitive, saltwater aquatic organisms should not be affected unac-
ceptably if the four-day average concentration of un-ionized ammonia does
not exceed 0.035 mg/L more than once every three years on the average and
if the one-hour average concentration does not exceed 0.233 mg/L more than
once every three years on the average. Because sensitive saltwater animals
appear to have narrow range of acute susceptibilities to ammonia, this crite-
rion will probably be as protective as intended only when the magnitudes
and/or durations of excursions are appropriately small.
   Criteria concentrations based on total ammonia for the pH range of 7.0
to 9.0, temperature range of 0 to 35°C, and  salinities of 10, 20 and 30 g/kg
are provided in Tables 5 and 6.  These values were calculated by  Hamp-
son's (1977) program  of  Whitfield's  (1974)  model  for hydrolysis  of
ammonium ions in sea water (see original document).

                                                               21

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Table 5. — Water quality criteria for saltwater aquatic life based on total ammonia (mg/L).
Criteria Maximum Concentrations
Temperature (°C)
pH 0

7.0
7.2
7.4
7.6
7.8
8.0
8.2
8.4
8.6
8.8
9.0

7.0
7.2
7.4
7.6
7.8
8.0
8.2
8.4
8.6
8.8
9.0

7.0
7.2
7.4
7.6
7.8
8.0
8.2
8.4
8.6
8.8
9.0

270
175
110
69
44
27
18
11
7.3
4.6
2.9

291
183
166
73
46
29
19
12
7.5
4.8
3.1

312
196
125
79
50
31
20
12.7
8.1
5.2
3.3
5

191
121
77
48
31
19
12
7.9
5.0
3.3
2.1

200
125
79
50
31
20
13
8.1
5.2
3.3
2.3

208
135
85
54
33
21
14
8.7
5.6
3.5
2.3
10

131
83
52
33
21
13
8.5
5.4
3.5
2.3
1.5

137
87
54
35
23
14
8.9
5.6
3.7
2.5
1.6

148
94
58
37
23
15
9.6
6.0
4.0
2.5
1.7
15
Salinity
92
58
35
23
15
9.4
5.8
3.7
2.5
1.7
1.1
Salinity
96
60
37
23
15
9.8
6.2
4.0
2.7
1.7
1.2
Salinity
102
64
40
25
16
10
6.7
4.2
2.7
1.8
1.2
20
= 10g/kg
62
40
25
16
10
6.4
4.2
2.7
1.8
1.2
0.85
= 20g/kg
64
42
27
17
11
6.7
4.4
2.9
1.9
1.3
0.87
= 30g/kg
71
44
27
21
11
7.3
4.6
2.9
2.0
1.3
0.94
25

44
40
25
16
10
6.4
4.2
2.7
1.8
1.2
0.85

44
29
18
11
7.5
4.8
3.1
2.0
1.4
0.94
0.69

48
31
19
12
7.9
5.0
3.3
2.1
1.4
1.0
0.71
30

29
19
12
7.7
5.0
3.1
2.1
1.4
0.98
0.71
0.52

31
20
12
7.9
5.2
3.3
2.1
1.5
1.0
0.73
0.54

33
21
13
8.5
5.4
3.5
2.3
1.6
1.1
0.75
0.56
35

21
13
8.3
5.6
3.5
2.3
1.5
1.0
0.75
0.56
0.44

21
14
8.7
5.6
3.5
2.3
1.6
1.1
0.77
0.56
0.44

23
15
9.4
6.0
3.7
2.5
1.7
1.1
0.81
0.58
0.46
                       In the Agency's best scientific judgment, the average amount of time
                    aquatic ecosystems should be provided between excursions is three years.
                    The ability of ecosystems to recover differ greatly.
                       Site-specific criteria may be established if adequate justification is pro-
                    vided. This site-specific criterion may include not only site-specific criteria
                    concentrations, and mixing zone considerations, but also site-specific du-
                    rations of averaging  periods  and site-specific  frequencies of allowed
                    exceedences.
22

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Table 6. — Water quality criteria for saltwater aquatic life based on total ammonia (mg/L).
Criteria Continuous Concentrations
Temperature (°C)
pH 0

7.0
7.2
7.4
7.6
7.8
8.0
8.2
8.4
8.6
8.8
9.0

7.0
7.2
7.4
7.6
7.8
8.0
8.2
8.4
8.6
8.8
9.0

7.0
7.2
7.4
7.6
7.8
8.0
8.2
8.4
8.6
8.8
9.0

41
26
17
10
6.6
4.1
2.7
1.7
1.1
0.69
0.44

44
27
18
11
6.9
4.4
2.8
1.8
1.1
0.72
0.47

47
29
19
12
7.5
4.7
3.0
1.9
1.2
0.78
0.50
5

29
18
12
7.2
4.7
2.9
1.8
1.2
0.75
0.50
0.31

30
19
12
7.5
4.7
3.0
1.9
1.2
0.78
0.50
0.34

31
20
13
8.1
5.0
3.1
2.1
1.3
0.83
0.53
0.34
10

20
12
7.8
5.0
3.1
2.0
1.3
0.81
0.53
0.34
0.23

21
13
8.1
5.3
3.4
2.1
1.3
0.84
0.56
0.37
0.24

22
14
8.7
5.6
3.4
2.2
1.4
0.90
0.59
0.37
0.26
15
Salinity =
14
8.7
5.3
3.4
2.2
1.4
0.87
0.56
0.37
0.25
0.17
Salinity =
14
9.0
5.6
3.4
2.3
1.5
0.94
0.59
0.41
0.26
0.18
Salinity =
15
9.7
5.9
3.7
2.4
1.6
1.0
0.62
0.41
0.27
0.19
20
10g/kg
9.4
5.9
3.7
2.4
1.5
0.97
0.62
0.41
0.27
0.18
0.13
20g/kg
9.7
6.2
4.1
2.5
1.6
1.0
0.66
0.44
0.28
0.19
0.13
30g/kg
11
6.6
4.1
3.1
1.7
1.1
0.69
0.44
0.30
0.20
0.14
25

6.6
4.1
2.6
1.7
1.1
0.69
0.44
0.29
0.20
0.14
0.10

6.6
4.4
2.7
1.7
1.1
0.72
0.47
0.30
0.20
0.14
0.10

7.2
4.7
2:9
1.8
1.2
0.75
0.50
0.31
0.22
0.15
0.11
30

4.4
2.8
1.8
1.2
0.75
0.47
0.31
0.21
0.15
0.11
0.08

4.7
3.0
1.9
1.2
0.78
0.50
0.31
0.22
0.15
0.11
0.08

5.0
3.1
2.0
1.3
0.81
0.53
0.34
0.23
0.16
0.11
0.08
35

3.1
2.0
1.2
0.84
0.53
0.34
0.23
0.16
0.11
0.08
0.07

3.1
2.1
1.3
0.84
0.53
0.34
0.24
0.16
0.12
0.08
0.07

3.4
2.2
1.4
0.90
0.56
0.37
0.25
0.17
0.12
0.09
0.07
Implementation
   Use of criteria for developing water quality-based permit limits and
for designing waste treatment facilities requires selecting an appropriate
wasteload allocation model. Dynamic models are preferred for the applica-
tion of these criteria. Limited data or other considerations might make
their use impractical, causing reliance on a steady-state model.

Water quality standards for ammonia developed from these criteria should
specify use of environmental monitoring methods that are comparable to
the analytical methods employed to generate the toxicity data base. Total
ammonia may be measured using an automated idophenol blue method,
                                                              23

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                    such as described by Technicon  Industrial Systems (1973) or U.S.  EPA
                    (1979) method 350.1. Un-ionized ammonia concentrations should be calcu-
                    lated using the dissociation model of Whitfield (1974) as programmed by
                    Hampson (1977). This program was used to calculate most of the un-ion-
                    ized values for saltwater organisms. Accurate measurement of sample pH
                    is crucial in the calculation of the un-ionized ammonia fraction. The fol-
                    lowing equipment and procedures were used by EPA in the ammonia
                    toxicity studies to enhance the precision of pH measurements in salt water.
                    The pH meter reported two decimal places. A Ross electrode with ceramic
                    junction was used because of its rapid response time; an automatic  tem-
                    perature compensation probe provided temperature correction. Note that
                    the responsiveness of a new electrode may be enhanced by holding it in
                    seawater for several days prior to use. Two National Institute of Standards
                    and Technology buffer solutions for calibration preferred for their stability
                    were (1) potassium hydrogen phthalate (pH 4.00) and (2) disodium hydro-
                    gen phosphate (pH 7.4). For overnight or weekend storage, the electrode
                    was held in salt water, leaving the fill hole open. For daily use, the outer
                    half-cell was  filled  with  electrolyte to the  fill  hole  and the electrode
                    checked for stability. The electrode pair was calibrated once daily prior to
                    measuring pH of samples; it was never recalibrated  during a series  of
                    measurements. Following calibration,  the electrode was soaked in sea
                    water, of salinity similar to the sample, for at least 15 minutes to achieve
                    chemical equilibrium and a steady-state junction potential. When measur-
                    ing pH, the sample was initially gently agitated or stirred to assure good
                    mixing at the electrode tip but without entraining air bubbles in the sam-
                    ple. Stirring was stopped to read the meter. The electrode was allowed to
                    equilibrate, so the change in meter reading was less than 0.02 pH unit/ m-
                    inute before recording. Following each measurement, the electrode was
                    rinsed with sea water and placed in fresh sea water for the temporary  stor-
                    age between measurements.


                    Fresh Water — (50 F.R. 30784, July 29,1985)
                    Salt Water — (54 F.R. 19227, May 4,1989)
                    See Appendix A for Aquatic Life Methodology.
24

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                                ANTIMONY
                                 CAS# 7440-36-0
CRITERIA

Aquatic Life
Human Health
The available data for antimony indicate that acute and chronic toxicity to
freshwater aquatic life occur at concentrations as low as 9,000 and 1,600
Hg/L, respectively, and would occur at lower concentrations among spe-
cies that are more sensitive than those tested. Toxicity to algae occurs at
concentrations as low as 610 ng/L.
   No saltwater organisms have been adequately tested with antimony,
and no statement can be made concerning acute or chronic toxicity.

For the protection of human health from the toxic properties of antimony
ingested through water and contaminated aquatic organisms, the ambient
water criterion is 146 ng/L.
   For the protection of human health from the toxic properties of anti-
mony  ingested through contaminated aquatic organisms alone,  the
ambient water criterion is 45 mg/L.
   Published human health critiera was  recalculated using Integrated
Risk Information System (IRIS) to reflect available data as of 10/92. Recal-
culated  IRIS  values  for antimony are 146.0  ng/L for  ingestion  of
contaminated water and organisms and 4,500 ng/L for ingestion of con-
taminated aquatic organisms only.
                   (45 F.R. 79318, November 28,1980)
                   See Appendix C for Human Health Methodology.
                                                                                25

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26

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                                   ARSENIC
                                   CAS# 7440-38-2
CRITERIA

Aquatic Life
Summary
Arsenic (III) —  Freshwater — 1-hour average of 360
                            4-day average of 190 ug/L
               Saltwater —  1-hour average of 69 ug/ L
                            4-day average of 36
The chemistry of arsenic in water is complex, and the form present in a so-
lution is dependent on environmental conditions such as Eh, pH, organic
content, suspended solids, and sediment. The relative toxicities of the vari-
ous forms of arsenic apparently vary from species to species. For inorganic
arsenic (III), acute values for 16 freshwater animal species ranged from 812
ug/L for a cladoceran to 97,000 ng/L for a midge, but the three acute-
chronic ratios only ranged from 4.660 to 4.862. The five acute values for
inorganic arsenic (V) covered about the same range, but the single acute-
chronic ratio was 28.71. The six acute values for MSMA ranged from 3,243
to 1,403,000 ug/L. The freshwater residue data indicated that arsenic is not
bioconcentrated to  a high degree, but that lower forms of aquatic life may
accumulate higher arsenic residues than fish. The low  bioconcentration
factor and  short half-life of arsenic in fish tissue suggest that residues
should not  be a problem to predators of aquatic life.
   The available data indicate that freshwater plants differ a great deal as
to their sensitivity to arsenic (III) and arsenic (V). In comparable tests, the
alga, Selenastrum capricornutum, was 45 times more sensitive to arsenic (V)
than to arsenic (III), although other data present conflicting information on
the sensitivity of this alga to arsenic (V). Many plant values for inorganic
arsenic (III) were in  the same range as the available chronic  values for
freshwater  animals; several plant values for arsenic (V)  were lower than
the one available chronic value.
   The other lexicological data revealed a wide range of toxicity based on
tests with a variety of freshwater species and endpoints. Tests with early
life stages appeared to be the most sensitive  indicator of arsenic toxicity.
Values obtained from this type of test with  inorganic arsenic (III) were
lower than  chronic  values. For example, an effect concentration of 40 ug/L
was obtained in a test on inorganic arsenic (III) with embryos and toad lar-
vae.
   Twelve species  of saltwater animals have acute values for inorganic ar-
senic (III) from 232 to 16,030 ug/L, and the single acute-chronic ratio is
1.945. The only values available for inorganic arsenic (V) are for two inver-
tebrate and are between 2,000 and 3,000 ng/L. Arsenic (III) and arsenic (V)
are equally toxic to various species of saltwater algae, but the sensitivities
of the species range from 19 ug/L to more than 1,000 ug/L. In a test with
an oyster, a BCF of  350 was obtained for inorganic arsenic (III).
                                                                                   27

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National Criteria The procedures described in the "Guidelines for Deriving Numerical Na-
                   tional Water Quality Criteria for the Protection of Aquatic Organisms and
                   Their Uses" indicate that, except possibly where a locally important spe-
                   cies is very sensitive, freshwater aquatic organisms and their uses should
                   not be affected unacceptably if the four-day average concentration of arse-
                   nic (HI) does not exceed 190 ug/L more than once every three years on the
                   average and if the one-hour average concentration  does not exceed 360
                   Hg/L more than once every three years on the average.
                       The procedures described in the guidelines indicate that, except possi-
                   bly where a locally important species is very sensitive, saltwater aquatic
                   organisms and their uses should not be affected unacceptably if the four-
                   day average concentration of arsenic (III) does not exceed 36 ug/L more
                   than once every three years on the average  and if the one-hour average
                   concentration does not exceed 69 ug/L more than once every three years
                   on the average. This criterion might be too high wherever Skeletonema cos-
                   rarum or Thalassiosira aestivalis are ecologically important.
                       Not enough data are available to allow derivation of numerical na-
                   tional water quality criteria for freshwater aquatic life for inorganic arsenic
                   (V) or any organic arsenic compound. Inorganic arsenic (V) is acutely toxic
                   to freshwater aquatic animals at concentrations as low as 850 ug/L, and an
                   .acute-chronic ratio of 28 was obtained with the fathead minnow. Arsenic
                   (V) affected freshwater aquatic plants at concentrations as low as 48 ng/L.
                   Monosodium methanearsenace (MSMA) is acutely toxic to aquatic animals
                   at concentrations as low as 1,900 ug/L, but no data are available concern-
                   ing chronic toxicity to animals or toxicity to plants.
                       Very few data are available concerning the toxicity of any form of arse-
                   nic other than inorganic arsenic (III) to saltwater aquatic life. The available
                   data do show that inorganic arsenic (V)  is acutely toxic to saltwater ani-
                   mals at concentrations as low as 2,319 ng/L and affected some saltwater
                   plants at 13 to 56 ng/L. No data are available concerning the chronic toxic-
                   ity of any form of arsenic other than inorganic arsenic  (III) to saltwater
                   aquatic life.
                       EPA believes that a measurement such as "acid-soluble" would  pro-
                   vide a more scientifically correct basis upon which to establish criteria for
                   metals. The criteria were developed on this basis. However, at this time no
                   EPA-approved methods for such a measurement  are  available to imple-
                   ment the criteria through the regulatory programs of the Agency and the
                   States. The Agency is considering development and  approval of methods
                   for a measurement such as acid-soluble. Until available, however, EPA rec-
                   ommends applying the criteria using the total recoverable method. This
                   has two impacts: (1) certain species of some metals cannot be analyzed di-
                   rectly because the total recoverable method does not distinguish between
                   individual oxidation states, and (2) these  criteria may be overly protective
                   when based on the total recoverable method.
                       The recommended exceedence frequency of three years is the Agency's
                   best scientific judgment of the average amount of time it will take an un-
                   stressed system to recover from a pollution event in  which exposure to
                   arsenic (III) exceeds the criterion. A stressed system, for example, one in
                   which several outfalls occur in a limited area, would be expected to require
                   more time for recovery. The resilience of ecosystems and their ability to re-
                   cover differ greatly, however, and site-specific criteria  may be established
                   if adequate justification is provided.
                       The use of criteria in designing waste treatment facilities requires the
                   selection of an appropriate wasteload allocation model. Dynamic models

28

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                   are preferred for the application of these criteria. Limited data or other fac-
                   tors may make their use impractical, in which case one should rely on a
                   steady-state model. The Agency recommends the interim use of 1Q5  or
                   1Q1O for Criterion Maximum Concentration design flow and 7Q5 or 7Q1O
                   for the Criterion Continuous Concentration  design flow in steady-state
                   models for unstressed and stressed systems, respectively. These matters
                   are discussed in more detail in EPA's  "Technical Support Document for
                   Water Quality-Based Toxics Control."

                   (50 F.R. 30784, July 29,1985)

Human Health
Criteria           For the maximum protection of human health from the potential carcino-
                   genic effects due to exposure  of inorganic arsenic through ingestion of
                   water and aquatic organisms that  are contaminated, the ambient water
                   concentration should be zero based on the non-threshold assumption for
                   this chemical.  However, zero level may not be attainable at the present
                   time. Therefore, the levels that may result in incremental increase of cancer
                   risk over the lifetime are estimated at 10"5,10"6, and 10"7.
                       Human health criteria were recalculated using Integrated Risk Infor-
                   mation System (IRIS) to reflect available data as of 12/92 (57 F.R. 60848).
                   Recalculated IRIS values for arsenic are 0.018 ng/L for ingestion  of con-
                   taminated  water  and  organisms  and  0.14  (ig/L  for  ingestion  of
                   contaminated aquatic organisms only. IRIS values are based on a 10  risk
                   level for carcinogens.
                   (45 F.R. 79318, November 28,1980) (50 F.R. 30784, July 29,1985)
                   (57 F.R. 60848, December 22,1993)
                   See Appendix A for Aquatic Life Methodology.
                   See Appendix C for Human Health Methodology.
                                                                                   29

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30

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                                ASBESTOS
                                 CAS# 1332-21-4
CRITERIA
Aquatic Life      No freshwater or saltwater organisms have been tested with any asbesti-
                   form mineral, therefore no statement can be made concerning its acute or
                   chronic toxicity.

Human Health    Published human health criteria were recalculated to reflect data as of
                   12/92 (57 F.R. 60911). For the maximum protection of human health from
                   the potential carcinogenic effects of exposure to asbestos through ingestion
                   of water and contaminated aquatic organisms, the ambient water concen-
                   tration should be zero. The estimated level that would  result in increased
                   lifetime cancer risks of 10"6 is 7,000,000 fibers/L. Estimates are for con-
                   sumption of aquatic organisms only, excluding the consumption of water.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60911, December 22,1993)
                   See Appendix C for Human Health Methodology.
                                                                                31

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32

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CRITERIA
                                  BACTERIA
Bathing Waters
(Full Body Contact)
Freshwater
Based on a statistically sufficient number of samples (generally not less
than five samples equally spaced over a 30-day period), the geometric
mean of the indicated bacterial densities should not exceed one of the fol-
lowing (as displayed in Table 1).

Based on a statistically sufficient number of samples (generally not less than
five samples equally spaced over a 30-day period), the geometric mean of the
indicated bacterial densities should not exceed one or the other of the follow-
ing:*
             E. co/i                       126 per 100 ml; or
             enterococci                  33 per 100 ml;
no sample should exceed a one-sided confidence limit (C.L.) calculated
using the following as guidance:
             designated bathing beach     75% C.L.
             moderate use for bathing     82% C.L.
             light use for bathing         90% C.L.
             infrequent use for bathing    95% C.L.

based  on a  site-specific log standard  deviation; or  if site  data are
insufficient to establish a log standard deviation, then using 0.4 as the log
standard deviation for both indicators.
Marine Water
Based on a statistically sufficient number of samples (generally not less
than five samples equally spaced over a 30-day period), the geometric
mean of the enterococci densities should not exceed 35 per 100 ml; no sam-
ple should exceed a one-sided confidence  limit using the  following as
guidance:
             designated bathing beach     75% C.L.
             moderate use for bathing     82% C.L.
             light use for bathing         90% C.L.
             infrequent use for bathing    95% C.L.

based on a site-specific log standard deviation; or if site data are insufficient
to establish a log standard deviation, then  using 0.7 as the  log standard
deviation.
                    *Only one indicator should be used. The regulatory agency should select the
                     appropriate indicator for its conditions.
                                                                                  33

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Shellfish
Harvesting
Waters              The median fecal coliform bacterial concentration should not exceed 14
                       Most Probable Number (MPN) per 100 mL, with not more than 10 percent
                       of samples exceeding 43 MPN per 100 mL for the taking of shellfish.
                          The microbiological criterion for shellfish water quality has been estab-
                       lished  by international agreement to be 70 total coliforms per  100 mL,
                       using a median MPN, with no more than 10 percent of the values exceed-
                       ing 230  total  coliforms  per 100  mL.  For  evaluation  of  waters  for
                       recreational taking of shellfish, EPA recommends  fecal coliform bacteria
                       rather  than total coliform bacteria.
                       REFERENCES:
                       Bathing Water Criteria - EPA 440 / 5-84-002
                       Bathing Water Criteria Laboratory Methods - EPA 600/4-85/076
                       Shellfish Water Criteria - Quality Criteria for Water (1976)
                       GPO Access #055-001-01049-4

                       (51 F.R. 8012, March 7,1986)


         Table 1.— Criteria for Indicator for biological densities.
SINGLE SAMPLE MAXIMUM ALLOWABLE DENSITY (4), (5)
ACCEPTABLE
SWIMMING
ASSOCIATED
GASTROENTERITIS
RATE PER 1000
SWIMMERS
STEADY-STATE
GEOMETRIC
MEAN
INDICATOR
DENSITY
DESIGNATED
BEACH AREA
(UPPER 75%
C.L)
MODERTEFULL
BODY CONTACT
RECREATION
(UPPER 82%C.L)
LIGHTLY USED
FULL BODY
CONTACT
RECREATION
(UPPER 90% C.L)
INFREQUENTLY
USED FULL BODY
CONTACT
RECREATION
(UPPER 95%C.L)
         Freshwater*
          enterococci           8            33(1)          61            78           107            151
          E. CO//               8            126(2)         235           298           409            575
         * Only one indicator should be used. The regulatory agency should select the appropriate indicator for its conditions.
         Marine Water
         enterococci            19            35(3)         104           158           276            501

         NOTES:
                   (1) Calculated to nearest whole number using equation:
                                                                        illness rafe/1000 people + 6.28
                                         (mean enterococci density) = antilog10  	r-rjj-—	

                   (2) Calculated to nearest whole number using equation:
                                                                    illness /afe/1000 people +11.74
                                         (mean E. coli density) = antilog 10	T-—=•—	

                   (3) Calculated to nearest whole number using equation:
                                                       ........    ///ness rate/1000 people- 0.20
                                         (mean enterococci density) = antilog10	   ^—	

                   (4) Single sample limit  =  antilog10
                              (log 10 indicator geometric mean   +   factor determined from areas     x   (Iog10 stand.
                              density/100ml)                    under the normal probability         deviation)
                                                             curve for the assumed level of
                                                             probability
                       The appropriate factors for the indicated one-sided confidence levels:
                                         75% C.L. — .675
                                         82% C.L — .935
                                         90% C.L —1.28
                                         95% C.L —1.65
                   (5) Based on the observed log standard deviations during the EPA studies: 0.4 for freshwater  E. co//and
                       enterococci; and 0.7 for marine water enterococci. Each jurisdiction should establish its own standard
                       deviation for its conditions, which would than vary the single sample limit.
34

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                                   BARIUM
                                  CAS# 7440-39-3
CRITERIA

Aquatic Life

Introduction
Human Health
1 mg/L for domestic water supply (health).

Barium is a yellowish white metal of the alkaline earth group. It occurs in
nature chiefly as barite (BaSO4) and witherite (BaCO3), both highly insol-
uble salts. The metal is stable in dry air but readily oxidized by humid air
or water.
    Many of the salts of barium are soluble in both water and acid; soluble
barium salts are reported to be poisonous. However, barium ions are gen-
erally thought to precipitate rapidly or be  removed from a solution by
absorption and sedimentation.
    While barium is a malleable, ductile metal, its major commercial value
is in its compounds. Barium compounds are  used in a variety of industrial
applications, including the metallurgic, paint, glass, and electronics indus-
tries, as well as for medicinal purposes.

For the protection of human health from the toxic properties of barium in-
gested through water and contaminated  aquatic organisms,  the ambient
water criterion is 1 mg/L.
                   (Quality Criteria for Water, July 1976) PB-263943
                   See Appendix D for Methodology.
                                                                                35

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36

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                                  BENZENE
                                    CAS# 71-43-2
CRITERIA

Aquatic Life
Human Health
The available data for benzene indicate that acute toxicity to freshwater
aquatic life occurs at concentrations as low as 5,300 ng/L and would occur
at lower concentrations among species that are more sensitive than those
tested. No data are available concerning the chronic toxicity of benzene to
sensitive freshwater aquatic life.
   The available data for benzene indicate that acute toxicity to saltwater
aquatic life occurs at concentrations as low as 5,100 ng/L and would occur
at lower concentrations among species that are more sensitive than those
tested. No definitive data are available  concerning the chronic toxicity of
benzene to sensitive saltwater aquatic life, but adverse effects occur at con-
centrations as low as 700 ng/L with a fish species exposed for 168 days.

For the maximum protection of human health from the potential carcino-
genic effects of exposure to benzene through ingestion of contaminated
water and contaminated aquatic organisms, the ambient water concentra-
tions  should  be  zero, based on the nonthreshold assumption for this
chemical. However, zero level may not be attainable at the present time.
   Published human health criteria were recalculated  using Integrated
Risk Information System  (IRIS) to  reflect  available data as of 12/92
(57 RR. 60911). Recalculated IRIS values for benzene are 1.2 fig/L for inges-
tion of contaminated water and organisms and 71 ng/L for ingestion of
contaminated aquatic organisms only. IRIS values are based on a 10"6 risk
level for carcinogens.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60911, December 22,1992)
                   See Appendix C for Human Health Methodology.
                                                                                  37

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38

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                                 BENZIDINE
                                   CAS# 92-87-5
CRITERIA

Aquatic Life
Human Health
The available data for benzidine indicate that acute toxicity to freshwater
aquatic life occurs at concentrations as low as 2,500 ng/L and would occur
at lower concentrations among species that are more sensitive than those
tested. No data are available concerning the chronic toxicity of benzidine
to sensitive freshwater aquatic life.
   Since saltwater organisms have not been tested with benzidine, no
statement can be made concerning its acute and chronic toxicity.

For the maximum protection of human health from the potential carcino-
genic effects of exposure to benzidine through ingestion of contaminated
water and contaminated aquatic organisms, the ambient water concentra-
tions  should be  zero, based on the nonthreshold  assumption for this
chemical. However, zero level may not be attainable at the present time.
Therefore, the levels that may result in an incremental increase of cancer
risk over a lifetime are estimated at 10"5,10"6, and 10"7.
   Published human health  criteria were recalculated using Integrated
Risk Information System (IRIS) to reflect  available  data as of 12/92
(57 F.R. 60913). Recalculated IRIS values for benzidine are 0.00012 ng/L for
ingestion of contaminated water and organisms and 0.00054 ng/L for in-
gestion of contaminated aquatic organisms only. IRIS values are based on a
10"6 risk level for carcinogens.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60913, December 22,1993)
                   See Appendix C for Human Health Methodology.
                                                                                  39

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40

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                                BERYLLIUM
                                 CAS# 7440-41-7
CRITERIA
Aquatic Life      The available data for beryllium indicate that acute and chronic toxicity to
                   freshwater aquatic life occur at concentrations as low as 130 and 5.3 ^/L,
                   respectively, and would occur at lower concentrations among species that
                   are more sensitive than those tested. Hardness has a substantial effect on
                   acute toxicity.
                      The limited saltwater database available for beryllium does not permit
                   any statement concerning acute or chronic toxicity.

Human Health    Human health criteria have been withdrawn  for this compound  (see
                   57 F.R. 60885, December 22,1992). Although the human health criteria are
                   withdrawn, EPA published a document for this compound that may con-
                   tain useful human  health information. This document was originally
                   noticed in 45 F.R. 79326, November 28,1980.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60911, December 22,1992)
                   See Appendix C for Human Health Methodology.
                                                                               41

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42

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             BENZENE HEXACHLORIDE (BHC)
                                CAS# 680-73-1
                       (See also: Hexachlorocyclohexane)
CRITERIA

Aquatic Life
The available data for a mixture of isomers of BHC indicate that acute tox-
icity to freshwater aquatic life occurs at concentrations as low as 100 ng/L
and would occur at lower concentrations among species that are more sen-
sitive than those tested.
   No data are available concerning the chronic toxicity of a mixture of
isomers of BHC to sensitive freshwater aquatic life.
   The available data for a mixture of isomers of BHC indicate that acute
toxicity to saltwater aquatic life occurs at concentrations as low as 0.34
Hg/L and would occur at lower concentrations  among species that are
more sensitive than those tested. No data are available concerning the
chronic toxicity of a mixture of isomers of BHC to sensitive saltwater
aquatic life.
                  (45 F.R. 79318, November 28,1980)
                  See Appendix B for Aquatic Life Methodology.
                                                                           43

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44

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                                    BORON
CRITERION
Introduction
Rationale
750 ng/L for long-term irrigation on sensitive crops. Data are insufficient
to determine acute or chronic toxicity of boron to freshwater or saltwater
aquatic life.

Boron is usually found as a sodium or calcium borate salt in nature, rather
than in an elemental form. Boron salts are used in fire retardants, produc-
tion of glass,  leather  tanning  and  finishing industries,  cosmetics,
photographic materials, metallurgy, and for high energy rocket fuels. Ele-
mental boron also can be used in nuclear reactors for neutron absorption.
Borates are used as "burnable" poisons.

Boron is an essential element for the growth of plants, but no evidence in-
dicates that it is required by animals. The maximum concentration found
in 1,546 samples of river and lake waters from various parts of the United
States was 5.0 mg/L; the mean value was 0.1 mg/L. Groundwaters could
contain substantially higher concentrations in certain places. The concen-
tration in sea  water is  reported as 4.5  mg/L in the form of borate.
Naturally  occurring concentrations of  boron should have no effect on
aquatic life.
    The minimum lethal dose for minnows exposed to boric acid at 20°C
for 6 hours was reported to be 18,000 to 19,000 mg/L in distilled water and
19,000 to 19,500 mg/L in hard water. In the dairy cow, 16 to 20 g/day of bo-
ric acid for 40 days produced no ill effects.
    Sensitive crops have shown toxic effects at 1,000 ug/L or less of boron.
When the boron concentration in irrigation waters was greater than 0.75
Hg/L, some sensitive plants such as citrus began to show injury. Water
containing 2 ug/L boron (with neutral and alkaline soils of high absorp-
tion capacities) might be used for some time without injury to sensitive
plants. The criterion of 750 ug/L is thought to protect sensitive crops dur-
ing long-term irrigation.
                   (Quality Criteria for Water, July 1976) PB-263943
                   See Appendix D for Methodology.
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                                  CADMIUM
                                  CAS# 7440-43-9
CRITERIA

Aquatic Life


Criteria
Saltwater — 1-hour average of 43.0
           4-day average of 9.3 ug/L
Freshwater criteria are hardness dependant. See text.

Freshwater acute values for cadmium are available for species in 44 genera
and range from 1.0 ng/L for rainbow trout to 28,000 ug/L for a mayfly. The
antagonistic effect of hardness  on acute toxicity has been demonstrated
with five species. Chronic tests have been conducted on cadmium with 12
freshwater fish species and four invertebrate species with chronic values
ranging from 0.15 ug/L for Daphnia magna to 156  ng/L for the Atlantic
salmon. Acute-chronic ratios are available for eight species and range from
0.9021 for the chinook salmon to 433.8 for the flagfish. Freshwater aquatic
plants are affected by cadmium at concentrations ranging from 2 to 7,400
Ug/L. These values are in the same range as the acute toxicity values for
fish and invertebrate species and are considerably above the chronic val-
ues.  Bioconcentration factors (BCFs)  for  cadmium in  freshwater range
from 164 to 4,190 for invertebrates and from 3 to 2,213 for fishes.
   Saltwater acute values for cadmium and five species of fishes range
from 577 ug/L for larval Atlantic silverside to 114,000  ^g/L for juvenile
mummichog.  Acute values for  30 species of  invertebrates range  from
15.5 ug/L for a mysid to 135,000 ug/L for an oligochaete worm. The acute
toxicity of cadmium generally increases as salinity decreases.
   The effect of temperature seems to be species-specific. Two life-cycle
tests with Mysidopsis bahia under different test conditions resulted in simi-
lar chronic values of 8.2 and 7.1 ng/L, but the acute-chronic ratios were 1.9
and 15, respectively. The acute  values appear to reflect effects of salinity
and temperature, whereas the few available chronic values apparently do
not.  A life-cycle test with Mysidopsis bigelowi also  resulted in a chronic
value of 7.1 ug/L and an acute-chronic ratio of 15. Studies with microalgae
and macroalgae revealed effects at 22.8 to 860 ng/L.
   BCFs determined with a variety of saltwater invertebrates ranged from
5 to 3,160. BCFs for bivalve molluscs were above 1,000 in long exposures,
with no indication that steady state had been reached. Cadmium mortality
is cumulative for exposure periods beyond four days. Chronic cadmium
exposure resulted in significant effects on the growth of bay  scallops at
78 ug/L and on reproduction of a copepod at 44 ng/L.
   The procedures described in the "Guidelines for Deriving Numerical
National Water Quality Criteria for the Protection of Aquatic  Organisms
and Their Uses" indicate that, except possibly where a locally important
species is very sensitive, freshwater aquatic organisms and their uses
should not be affected unacceptably if the four-day  average concentration
(in ug/L) of cadmium does not exceed the numerical value given  by
                       e(0.7852[ln(hardness)]-3.490)

                                                               47

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                   more than once every three years on the average and if the one-hour
                   average  concentration (in ng/L)  does  not exceed the numerical value
                   given by
                                          _(1.128[ln(hardness))-3.828)
                                          "
                   more than  once every three  years on the  average. For  example, at
                   hardnesses of 50,  100, and 200 mg/L as  CaCOj, the four-day  average
                   concentrations of cadmium are 0.66, 1.1, and 2.0 jig/L, respectively, and
                   the one-hour average concentrations are 1.8, 3.9, and 8.6 ug/L. If brook
                   trout, brown trout, and striped  bass are as sensitive as some data indicate,
                   they might not be protected by  this criterion.
                       The procedures described in the guidelines indicate that, except possi-
                   bly where a locally important  species is very sensitive, saltwater aquatic
                   organisms and their uses should not be affected unacceptably if the four-
                   day average concentration of  cadmium does  not exceed 9.3 ug/L more
                   than once every three years on the average, and if the one-hour  average
                   concentration does not exceed  43 ng/L more than once every three years
                   on the average.
                       The little information that is available concerning the sensitivity of the
                   American lobster to cadmium indicates that this important species might
                   not be protected by this criterion. In addition,  data suggest that the acute
                   toxicity of cadmium is salinity dependent; therefore, the one-hour average
                   concentration might be underprotective at  low salinities and overprotec-
                   tive at high salinities.
                       The recommended exceedence frequency of three years is the Agency's
                   best scientific judgment of the  average amount of time it will take an un-
                   stressed  system  to recover from a pollution event in which exposure to
                   cadmium exceeds the criterion. A stressed system,  for example, one in
                   which several outfalls occur in a limited area, would be expected to require
                   more time for recovery. The resilience of ecosystems and their ability to re-
                   cover differ greatly, however, and  site-specific  criteria may be established
                   if adequate justification is provided.
                       The use of criteria in designing waste treatment facilities requires the
                   selection of an appropriate wasteload allocation model. Dynamic models
                   are preferred for the application of these criteria. Limited data or other fac-
                   tors may make their use impractical, in which case one should rely on a
                   steady-state model. The Agency recommends  the interim use of 1Q5 or
                   1Q1O for Criterion Maximum Concentration design flow and 7Q5 or 7Q1O
                   for the Criterion Continuous Concentration design flow in steady- state
                   models  for unstressed and stressed systems, respectively.  These  matters
                   are discussed in more detail in the "Technical Support Document for Water
                   Quality-Based Toxics Control."

Human Health
Criteria           Human  health criteria have been withdrawn  for this compound (see
                   57 F.R. 60885, December 22,1992).  Although the human health criteria are
                   withdrawn, EPA published a document for this compound that may con-
                   tain useful  human health  information. This   document was originally
                   noticed in 45 F.R. 79326, November 28,1980.
                    (45 F.R. 79318, November 28,1980) (50 F.R. 30784, July 29,1985)
                    (57 F.R. 60885, December 22,1992)
                    See Appendix A for Aquatic Life Methodology.

48

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                   CARBON TETRACHLORIDE
                                   CAS# 56-23-5
CRITERIA

Aquatic Life
Human Health
The available data for carbon tetrachloride indicate that acute toxicity to
freshwater aquatic life occurs at concentrations as low as 35,200 ng/L and
would occur at lower concentrations among species that are more sensitive
than those tested. No data are available concerning the chronic toxicity of
carbon tetrachloride to sensitive freshwater aquatic life.
   The available data for carbon tetrachloride indicate that acute toxicity
to saltwater aquatic life occurs at concentrations as low as 50,000 ng/L and
would occur at lower concentrations among species that are more sensitive
than those tested. No data are available concerning the chronic toxicity of
carbon tetrachloride to sensitive saltwater aquatic life.

For the maximum protection of human health from the potential carcino-
genic  effects of exposure to  carbon tetrachloride through ingestion of
contaminated water and contaminated aquatic organisms, the  ambient
water concentrations should be zero, based on the nonthreshold  assump-
tion for this chemical. However, zero level may not be attainable at the
present time. Therefore, the levels that may result in incremental increase
of cancer risk over a lifetime are estimated at 10'5,10"6, and 10"7.
   Published human health criteria were recalculated using Integrated
Risk Information  System (IRIS) to reflect available data  as of  12/92
(57 F.R. 60911, December 22,1992). Recalculated IRIS values for carbon tet-
rachloride are 0.25 (ig/L  for  ingestion  of contaminated water and
organisms and 4.4 n.g/L for ingestion of contaminated aquatic life organ-
isms. IRIS values are based on a 10"6 risk level for carcinogens.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60911, December 22,1992)
                   See Appendix C for Human Health Methodology.
                                                                                49

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50

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                               CHLORDANE
                                   CAS# 57-74-9
CRITERIA

Aquatic Life
Human Health
 For chlordane, the criterion to protect freshwater aquatic life as derived us-
 ing the guidelines is 0.0043 ng/L as a 24-hour average. The concentration
 should not exceed 2.4 ng/L at any time.
    For chlordane, the criterion to protect saltwater aquatic life as derived
 using the guidelines is 0.0040 ng/L as a 24-hour average. The concentra-
 tion should not exceed 0.09 ng/L at any time.

 For the maximum protection of human health from the potential carcino-
 genic effects of exposure to chlordane through ingestion of contaminated
 water and contaminated aquatic organisms, the ambient water concentra-
.tion should be zero based on the  nonthreshold assumption  for this
 chemical. However, zero level may not be attainable at the present time.
 Therefore, the levels that may result in incremental increase of cancer risk
 over a lifetime are estimated at 10"5,10"6, and 10"7.
    Published human health criteria  were recalculated using Integrated
 Risk Information System (IRIS) to  reflect available  data as of 12/92
 (57 F.R. 60914, December 22,1992). Recalculated IRIS values for chlordane
 are 0.00057 ng/L for ingestion of contaminated water and organisms and
 0.00059 |Ag/L for ingestion of contaminated aquatic organisms only. IRIS
 values are based on a 10"6 risk level for carcinogens.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60914, December 22,1992)
                   See Appendix B for Aquatic Life Methodology.
                   See Appendix C for Human Health Methodology.
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52

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                                 CHLORIDE
                                 CAS# 16887-00-6
CRITERIA
Aquatic LifG      Not to exceed a one-hour average of 860 mg/L or a four-day average of
                   230 mg/L for freshwater aquatic life.
                      The procedures described in the "Guidelines for Deriving Numerical
                   National Water Quality Criteria for the Protection of Aquatic Organisms
                   and Their Uses" indicate that, except possibly where a locally important
                   species is very sensitive, freshwater aquatic organisms and their uses
                   should not be affected unacceptably if the four-day average concentration
                   of dissolved chloride, when associated with sodium, does not exceed 230
                   mg/L more than once every three years on the average and if the one-hour
                   average concentration does not exceed 860 mg/L more than once every
                   three years on the average.
                      These criteria probably will not be  adequately protective when the
                   chloride is associated with potassium, calcium, or magnesium, rather than
                   sodium. In addition, because freshwater animals have a narrow range of
                   acute susceptibilities to chloride, excursions above these criteria might af-
                   fect a substantial number of species.
                   (53 F.R. 19028, May 26,1988)
                   See Appendix A for Aquatic Life Methodology.
                                                                                 53

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54

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                    CHLORINATED  BENZENES
CRITERIA
Aquatic Life       The available data for chlorinated benzenes indicate that acute toxicity to
                   freshwater aquatic life would occur at concentrations as low as 250 (ig/L
                   and at lower concentrations among species that are more sensitive than
                   those tested. No data are available concerning the chronic toxicity of the
                   more toxic of the chlorinated benzenes to sensitive freshwater aquatic life,
                   but toxicity occurs at concentrations as low as 50 ng/L for a fish species ex-
                   posed for 7.5 days.
                      The available data for chlorinated benzenes indicate that acute and
                   chronic toxicity to saltwater aquatic life occur at concentrations as low as
                   160 and 129 ng/L, respectively, and would occur at lower concentrations
                   among species that are more sensitive than those tested.

Human Health

Monochlorobenzene (Chlorobenzene) 108-90-7
                   Published human health criteria were recalculated using Integrated Risk
                   Information  System  (IRIS)  to  reflect  available  data as  of 12/92
                   (57 F.R. 60911, December 22,1992). Recalculated IRIS values for chloroben-
                   zene are 680.0 ng/L for contaminated water and organisms and 21,000
                   Hg/L for ingestion of contaminated aquatic organisms only.
Trichlorobenzenes
                   Because of insufficiency in the available information for the trichloroben-
                   zenes,  a  criterion cannot be derived at this time using the present
                   guidelines.
1,2,4,5-Tetrachlorobenzene 95-94-3
                   For the protection of human health from the toxic properties of 1,2,4,5-
                   tetrachlorobenzene  ingested through water and  contaminated  aquatic
                   organisms, the ambient water criterion is determined to be 38 ng/L.
                      For the protection of human health from the toxic properties of 1,2,4,5-
                   tetrachlorobenzene  ingested through contaminated  aquatic  organisms
                   alone, the ambient water criterion is determined to be 48
Pentachlorobenzene 608-93-5
                   For the protection of human health from the toxic properties of pentachlo-
                   robenzene ingested through water and contaminated aquatic organisms,
                   the ambient water criterion is determined to be 74 ng/L.
                       For the protection of human health from the toxic properties of pen-
                   tachlorobenzene ingested through contaminated aquatic organisms alone,
                   the ambient water criterion is determined to be 85 ng/L.
                                                                                55

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Hexachlorobenzene 118-74-1
                   For the maximum protection of human health from the potential carcino-
                   genic effects due to exposure of hexachlorobenzene through ingestion of
                   contaminated  water and contaminated aquatic organisms,  the ambient
                   water concentration should be zero based on the nonthreshold assumption
                   for this chemical. However, zero level may not be attainable at the present
                   time. Therefore, the levels that may result in incremental increase of cancer
                   risk over a lifetime are estimated at 10"5,10  , and 10" .
                       Published human health criteria were recalculated using IRIS to reflect
                   available data as of 12/92 (57 F.R. 609121, December 22,1992). The recalcu-
                   lated IRIS value for chlorinated benzenes is .00075 ng/L for ingestion of
                   contaminated water and organisms and 0.00077 (ig/L for ingestion of con-
                   taminated organisms only. IRIS values are based on a 10  risk level for
                   carcinogens.
                    (45 F.R. 79318, November 28,1980) (57 F.R. 60848, December 22,1992)
                    See Appendix C for Human Health Methodology.
56

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                     CHLORINATED ETHANES
CRITERIA

Aquatic Life
The available freshwater data for chlorinated ethanes indicate that toxicity
increases greatly with increasing chlorination and that acute toxicity oc-
curs at  concentrations  as low as  118,000 ng/L for 1,2-dichloroethane;
18,000  ng/L for two trichloroethanes;  9,320  jig/L for two  tetrachlo-
roethanes; 7,240 ng/L for pentachloroethane; and 980 ng/L for hexachloro-
ethane.
   Chronic toxicity occurs at concentrations as low as 20,000 ng/L for 1,2-
dichloroethane; 9,400 (ig/L for 1,1,2-trichchloroethane; 2,400  ng/L for
1,1,2,2-tetrachloroethane; 1,100 ng/L for pentachloroethane; and 540 ng/L
for hexachloroethane. Acute and chronic toxicity would occur at lower
concentrations among species that are more sensitive than those tested.
   The available saltwater data for chlorinated ethanes indicate that toxic-
ity increases greatly with increasing chlorination and that acute toxicity to
fish and invertebrate species occurs at concentrations as low as 113,000
Hg/L for 1,2-dichloroethane; 31,200 jig/L for 1,1,1-trichloroethane; 9,020
Hg/L for 1,1,2,2-tetrachloroethane;  390 (ig/L for pentachloroethane; and
940 jig/L for hexachloroethane.
   Chronic toxicity occurs at concentrations  as low as 281 ng/L for pen-
tachloroethane. Acute  and chronic  toxicity would   occur  at lower
concentrations among species that are more sensitive than those tested.
Human Health
1,2-Dichloroethane 107-06-2
                   For the maximum protection of human health from the potential carcino-
                   genic  effects of exposure to 1,2-dichloroethane  through ingestion of
                   contaminated water and contaminated aquatic organisms, the ambient
                   water concentration should be zero, based on the  nonthreshold assump-
                   tion for this chemical. However, zero level may not be attainable at the
                   present time. Therefore, the levels that may result in incremental increase
                   of cancer risk over a lifetime are estimated at 10"5,10"6, and 10" .
                       Health criteria were recalculated using Integrated Risk Information
                   System (IRIS) to reflect available data as of 12/92 (57 F.R. 60848). Recalcu-
                   lated IRIS  values for  1,2-dichloroethane are 0.38  ng/L for ingestion of
                   contaminated water and organisms and 99 ng/L for ingestion of contami-
                   nated aquatic organisms only. IRIS values are based on 10  risk level for
                   carcinogens.
1,1,2-Trichloroethane 79-00-5
                   For the maximum protection of human health from the potential carcino-
                   genic effects of exposure  to 1,1,2-trichloroethane  through  ingestion  of
                   contaminated water and contaminated aquatic organisms,  the ambient
                   water concentration should be zero, based on the nonthreshold assump-
                   tion for this chemical. However, zero level may  not be attainable at the
                                                                                 57

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                   present time. Therefore, the levels that may result in incremental increase
                   of cancer risk over a lifetime are estimated at 10"5,10"6, and 10~7.
                       Human health criteria were recalculated using IRIS to reflect available
                   data as of 12/92 (57 F.R. 60948). Recalculated IRIS values for 1,1,2-trichlo-
                   roethane are 0.60 ug/L for ingestion of contaminated water and organisms
                   and 42 ug/L for ingestion of contaminated aquatic organisms only. IRIS
                   values are based on a 10"6 risk level for carcinogens.
1,1,2,2-Tetrachloroethane 79-34-5
                   For the maximum protection of human health from the potential carcino-
                   genic effects of exposure to 1,1/2,2-tetrachloroethane through ingestion of
                   contaminated water and contaminated aquatic organisms, the ambient
                   water concentration should be zero, based on the nonthreshold assump-
                   tion for this chemical. However, zero  level may not be attainable at the
                   present time. Therefore, the levels that may result in incremental increase
                   of cancer risk over the lifetime are estimated at 10"5,10"6, and 10'7.
                       Human health criteria were recalculated using IRIS to reflect available
                   data  as of 12/92 (57 F.R. 60848). Recalculated IRIS values  for 1,1,2,2-
                   tetrachloroethane are 0.17 (ig/L for ingestion of contaminated water and
                   organisms and 11.0 ng/L for ingestion of contaminated aquatic organisms
                   only. IRIS values are based on a 10"6 risk level for carcinogens.
Hexachloroethane 67-72-1
                   For the maximum protection of human health from the potential carcino-
                   genic  effects  of  exposure to hexachloroethane  through  ingestion  of
                   contaminated  water and contaminated aquatic organisms, the ambient
                   water concentration should be zero, based on the nonthreshold assump-
                   tion for this chemical. However, zero  level may not be attainable at the
                   present time. Therefore, the levels that may result in incremental increase
                   of cancer risk over the lifetime are estimated at 10 ,10"6, and 10* .
                       Human health criteria were recalculated using IRIS to reflect available
                   data as of 12/92  (57 F.R. 60848). Recalculated IRIS values for hexachlo-
                   roethane are 1.9 ng/L for ingestion of contaminated water and organisms
                   and 8.9 ng/L for  ingestion of contaminated aquatic organisms only. IRIS
                   values are based on 10"6 risk level for carcinogens.
1,1,1-Trichloroethane 71-55-6
                   Human health criteria have been withdrawn for one chlorinated ethane,
                   1,1,1-trichloroethane (see 57 F.R. 60885, December 22,1992). Although the
                   human health criteria are withdrawn, EPA published a document for this
                   compound that may contain useful human health information. This docu-
                   ment was originally noticed in 45 F.R. 79328, November 28,1980.

                       Because of insufficient available  data  for monochloroethane, 1,1-
                   dichloroethane, 1,1,1,2-tetrachloroethane, and pentachloroethane, satisfac-
                   tory criteria cannot be derived at this time using the present guidelines.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60848, December 22,1992)
                   See Appendix C for Human Health Methodology.
58

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               CHLORINATED  NAPHTHALENES
CRITERIA

Aquatic Life
Human Health
The available data for chlorinated naphthalenes indicate that acute toxicity
to freshwater aquatic life occurs at concentrations as low as 1,600 ng/L and
would occur at lower concentrations among species that are more sensitive
than those tested. No data are available concerning the chronic toxicity of
chlorinated naphthalenes to sensitive freshwater aquatic life.
   The available data  for chlorinated naphthalenes  indicate that acute
toxicity to saltwater aquatic life occurs at concentrations as low as 7.5 ng/L
and would occur at lower concentrations among species that are more sen-
sitive than those tested. No data are available  concerning the chronic
toxicity of chlorinated naphthalenes to sensitive saltwater aquatic life.

Human health criteria was calculated for 2-chloronaphthelene using Inte-
grated Risk Information System (IRIS) to reflect available data as of 12/92
(57 F.R.  60890).  The calculated  IRIS values  for 2-chloronaphthelene is
1,700 ng/L for ingestion of contaminated  water and organisms and
4,300 mg/ L for organisms only.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60890, December 22,1992)
                   See Appendix B for Aquatic Life Methodology.
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                     CHLORINATED PHENOLS
CRITERIA
Aquatic Life
Human Health

3-Chlorophenol
The available freshwater data for chlorinated phenols indicate that toxicity
generally increases with increased chlorination and that acute toxicity oc-
curs at concentrations as low as 30 ng/L for 4-chloro-3-methylphenol to
greater than 500,000 ng/L for other compounds. Chronic toxicity occurs at
concentrations as low as 970 ng/L for 2,4,6-trichlorophenol. Acute and
chronic toxicity would occur at lower concentrations among species that
are more sensitive than those tested.
   The available saltwater data for chlorinated phenols indicate that tox-
icity generally increases with increasing chlorination and that acute
toxicity occurs at concentrations as low as 440 ng/L for 2,3,5,6-tetrachlo-
rophenol and 29,700 ng/L for 4-chlorophenol.  Acute  toxicity would occur
at lower concentrations among species that are more sensitive than those
tested. No data are available concerning the chronic toxicity of chlorinated
phenols to sensitive saltwater aquatic life.
                   Sufficient data are not available for 3-chlorophenol to derive a level that
                   would protect against the potential toxicity of this compound. According
                   to available organoleptic data, the estimated level is 0.1 ng/L to control un-
                   desirable taste and odor qualities of ambient water. Organoleptic data do
                   have limitations as a basis for establishing a water quality criterion but do
                   not have a demonstrated relationship to potentially adverse effects on hu-
                   man health.
4-Chlorophenol 106-48-9
                   Sufficient data are not available for 4-chlorophenol to derive a level that
                   would protect against the potential toxicity of this compound. According
                   to available organoleptic data, to control undesirable taste and odor quali-
                   ties of ambient water the estimated level is 0.1 ug/L. Organoleptic data do
                   have limitations as a basis for establishing a water quality criterion but do
                   not have a demonstrated relationship to potentially adverse effects on hu-
                   man health.
2,3-Dichlorophenol
                    Sufficient data are not available for 2,3-dichlorophenol to derive a level
                    that would protect against the potential toxicity of this compound. Accord-
                    ing to available organoleptic data,  the estimated level is 0.04 ug/L to
                    control undesirable taste and odor qualities of ambient water. Organolep-
                    tic data  do have limitations as a basis for establishing a water quality
                    criterion but do not have a demonstrated relationship to potentially ad-
                    verse effects on human health.

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2,5-Dichlorophenol
2,6-Dichlorophenol
3,4-Dichlorophenol
                    Sufficient data are not available for 2,5-dichlorophenol to derive a level
                    that would protect against the potential toxitity of this compound. Accord-
                    ing to available organoleptic data, the estimated level is 0.5 ng/L to control
                    undesirable taste and odor qualities of ambient water. Organoleptic data
                    do have limitations as a basis for establishing a water quality criterion but
                    do not have a demonstrated relationship to potentially adverse effects on
                    human health.
                    Sufficient data are not available for 2,6-dichlorophenol to derive a level
                    that would protect against the potential toxicity of this compound. Accord-
                    ing to available organoleptic data, to  control undesirable taste and odor
                    qualities of ambient water, the estimated level is 0.2 ng/L. Organoleptic
                    data do have limitations as a basis for establishing a water quality criterion
                    but do not have a demonstrated relationship to potentially adverse effects
                    on human health.
                   .Sufficient data are not available for 3,4-dichlorophenol to derive a level
                    that would protect against the potential toxicity of this compound. Accord-
                    ing to available organoleptic data, to  control undesirable taste and odor
                    qualities of ambient water, the estimated level is 0.3 ug/L. Organoleptic
                    data do have limitations as a basis for establishing a water quality criterion
                    but do not have a demonstrated relationship to potentially adverse effects
                    on human health.
2,4,5-Trichlorophenol 95-95-4
                    For comparison purposes, two approaches were used to derive criterion
                    levels for 2,4,5-trichlorophenol. Based on available toxicity data, to protect
                    public health, the derived level is 2.6 mg/L. Using available organoleptic
                    data, to control undesirable taste and odor quality of ambient water, the es-
                    timated level is 1.0 ng/L. Organoleptic data do have limitations as  a basis
                    for establishing a water quality criterion but do not have a demonstrated
                    relationship to potentially adverse effects on human health.
2,4,6-Trichlorophenol 88-06-2
                    For the maximum protection of human health from the potential carcino-
                    genic effects of exposure to 2,4,6-trichlorophenol through the ingestion of
                    contaminated water and contaminated aquatic organisms, the ambient
                    water concentration should be zero, based on the nonthreshold assump-
                    tion for this chemical. However, zero level may not be attainable at the
                    present time. Therefore, the levels that may result in incremental increase
                    of cancer risk over a lifetime are estimated at 10"5,10"6, and 10"7.
                       Human health criteria were recalculated using Integrated Risk Infor-
                    mation System (IRIS) to reflect available data as of 12/92 (57 F.R. 60848).
                    Recalculated IRIS values for 2,4,6-Trichlorophenol are 2.1 ng/L for inges-
                    tion of contaminated water and organisms and 6.5 ng/L for ingestion of
                    contaminated organisms only. IRIS values are based on a 10"6 risk level for
                    carcinogens.
62

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2,3,4,6-Tetrachlorophenol
                    Sufficient data are not available for 2,3,4,6-tetrachlorophenol to derive a
                    level that would protect against the potential toxicity of this compound.
                    According to available organoleptic data, to control undesirable taste and
                    odor qualities of ambient water the estimated level is 1.0 ng/L. Organolep-
                    tic data have limitations as a basis for establishing a water quality criterion
                    and a demonstrated relationship to potentially adverse effects on human
                    health.
2-Methyl-4-Chlorophenol
                    Sufficient data are not available for 2-methyl-4-chlorophenol to derive a
                    criterion level that would protect against any potential toxicity of this com-
                    pound.  According to  available  organoleptic data, to control undesirable
                    taste and odor qualities of ambient water, the estimated level  is 1,800
                    [ig/L. Organoleptic data do have limitations as a basis for establishing a
                    water quality criterion but do not have a demonstrated relationship to po-
                    tentially adverse effects on human health.
3-Methyl-4-Chlorophenol 59-50-7
                    Sufficient data are not available for 3-methyl-4-chlorophenol to derive a
                    criterion level that would protect against any potential toxicity of this com-
                    pound.  According to  available  organoleptic data, to control undesirable
                    taste and odor qualities of ambient water, the estimated level  is 3,000
                    ug/L. Organoleptic data do have limitations as a basis for establishing a
                    water quality criterion but do not have a demonstrated relationship to po-
                    tentially adverse effects on human health.
3-Methyl-6-Chlorophenol
                    Sufficient data are not available for 3-methyl-6-chlorophenol to derive a
                    criterion level that would protect against any potential toxicity of this com-
                    pound. According to available organoleptic data, the estimated level is 20
                    Ug/L to control undesirable taste and odor qualities of ambient water.  Or-
                    ganoleptic  data do have limitations as a basis for establishing a water
                    quality criterion but do not have a demonstrated relationship to poten-
                    tially adverse effects on human health.
                    (45 F.R. 79318, November 28,1980) (57 F.R. 60848, December 22,1992)
                    See Appendix C for Human Health Methodology.
                                                                                     63

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64

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                                 CHLORINE
                                  CAS# 7782-50-5
CRITERIA

Aquatic Life
Summary
Freshwater -

Saltwater —
4-day average of 11 ng/L
1-hour average of 19 ng/L
4-day average of 7.5 ng/L
1-hour average of 13 ng/L
Thirty-three freshwater species in 28 genera have been exposed to total re-
sidual chlorine (TRC); the acute values range from 28 ng/L for Daphnia
magna to 710 ng/L for the threespine stickleback. Fish and invertebrate spe-
cies had similar ranges of sensitivity. Freshwater chronic tests have been
conducted with two invertebrate and one fish species. The chronic values
for these  three species ranged from less  than 3.4 to 26  ng/L, with acute-
chronic ratios from 3.7 to greater than 78.
   The acute sensitivities of 24 species of saltwater animals in 21 genera
have been determined for CPO, and  the LC50 range is from 26 ng/L for
the eastern oyster to 1,418 ng/L for a mixture of two shore crab species.
This range is very similar to that observed with freshwater species: fishes
and invertebrates had similar sensitivities. Only one chronic test has been
conducted with a saltwater species, Menidia peninsulae; the acute chronic
ratio was 1.162.
   The available data indicate that aquatic plants are more resistant to
chlorine than fish and invertebrate species.
National Criteria The procedures described in the "Guidelines for Deriving Numerical Na-
                   tional Water Quality Criteria for the Protection of Aquatic Organisms and
                   Their Uses" indicate that, except possibly where  a locally important spe-
                   cies is very sensitive, freshwater aquatic organisms and their uses should
                   not be affected unacceptably if the four-day average concentration of total
                   residual chlorine does not exceed 11 ng/L more than once every three
                   years on the average, and if the one-hour average concentration does not
                   exceed 19 ng/L more than once every three years on the average.
                       The procedures described  in the guidelines indicate that saltwater
                   aquatic organisms and their uses should not be affected unacceptably (ex-
                   cept possibly where a locally important species  is very  sensitive) if the
                   four-day average concentration of chlorine-produced  oxidants does not
                   exceed 7.5 ng/L more than once every three years on the average, and if
                   the one-hour average concentration does not exceed 13 ng/L more than
                   once every three years on the average.
                       The recommended exceedence frequency of three years is the Agency's
                   best scientific judgment of the average amount of time for  an unstressed
                   system to recover from a pollution event in which exposure to chlorine ex-
                   ceeds the criterion. A stressed system — for example, one in which several

                                                                                 65

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                  outfalls occur in a limited area —would be expected to require more time
                  for recovery. An ecosystem's resilience and ability to recover differ greatly,
                  however, and site-specific criteria may be established if adequate justifica-
                  tion is provided.
                     The use of criteria in designing waste treatment facilities requires the
                  selection of an appropriate wasteload allocation model. Dynamic models
                  are preferred for the application of these criteria; however, if limited data
                  or other factors make their  use impractical, one should rely on a steady-
                  state model. The Agency recommends the interim use of 1Q5 or 1Q1O for
                  Criterion Maximum Concentration design flow and 7Q5  or 7Q1O for the
                  Criterion Continuous Concentration design flow in steady-state models
                  for unstressed and stressed systems, respectively. These  matters are dis-
                  cussed in more detail in EPA's  "Technical Support Document for Water
                  Quality-Based Toxics Control."
                  (50 F.R. 30784, July 29,1985)
                  See Appendix A for Aquatic Life Methodology.
66

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                      CHLOROALKYL ETHERS
CRITERIA
Aquatic Life      The available data for chloroalkyl ethers indicate that acute toxicity to
                   freshwater aquatic life occurs at concentrations as low as 238,000 ng/L and
                   would occur at lower concentrations among species that are more sensitive
                   than those tested. No definitive data are available concerning the chronic
                   toxicity of chloroalkyl ethers to sensitive freshwater aquatic life.
                      No saltwater organism has been tested with any chloroalkyl ether, and
                   therefore, no statement can be made concerning acute or chronic toxicity.

Human Health

Bis(Z-Chloroisopropyl) 108-60-1
                   Human health criteria were  recalculated using Integrated Risk  Informa-
                   tion System (IRIS) to reflect available data as of  12/92 (57 F.R. 60848).
                   Recalculated IRIS values for bis(2-chloroisopropyl) ether are 1,400 ng/L
                   for ingestion of contaminated water and organisms and 170,000  ng/L for
                   ingestion of contaminated aquatic organisms only.

Bis(Chloromethyl)
                   For the maximum protection of human health from the potential carcino-
                   genic  effects of exposure to bis(chloromethyl) ether through ingestion of
                   contaminated water and contaminated aquatic organisms,  the ambient
                   water concentrations should be zero, based on the nonthreshold assump-
                   tion for this chemical. However,  zero level may not be attainable at the
                   present time. Therefore, the levels that may result in incremental increase
                   of cancer risk over the lifetime are estimated at 10", 10 , and 10" . The cor-
                   responding recommended criteria are 37.6 x 10"6 ng/L, and 0.376 x 10"6
                   Hg/L, respectively. If these estimates are made for consumption of aquatic
                   organisms only, excluding consumption of water, the levels are 18.4 x 10"
                   Hg/L, 1.84 x 10"3 ng/L, respectively.

Bis(2-Chloroethyl) 111-44-4
                   For the maximum protection of human health from the potential carcino-
                   genic  effects of exposure to bis(2-chloroethyl) ether through ingestion of
                   contaminated water and contaminated aquatic organisms,  the ambient
                   water concentrations should be zero based on the nonthreshold assump-
                   tion for this chemical. However,  zero level may not be attainable at the
                   present time. Therefore, the levels that may result in incremental increase
                   of cancer risk over a lifetime are estimated at 10"5,10"6, and 10"7.The corre-
                   sponding recommended criteria  are  0.30 ng/L, 0.030  ng/L, and 0.003
                   Hg/L, respectively. If these estimates are made for consumption of aquatic
                   organisms only, excluding consumption of water, the levels are 13.6 ug/L,
                   1.36 ng/L, and 0.136 ng/L, respectively.


                   (45 F.R. 79318, November 28,1980)
                   See Appendix C for Human Health Methodology.
                                                                                67

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68

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                              CHLOROFORM
                                   CAS# 67-66-3
CRITERIA

Aquatic Life
Human Health
The available data for chloroform indicate that acute toxicity to freshwater
aquatic life occurs at concentrations as low as 28,900 ng/L and would oc-
cur at lower concentrations among species that are more sensitive than the
three tested species. As indicated by 27-day LC50 values, chronic toxicity
occurs at concentrations as low as 1,240 ng/L and could occur at lower
concentrations among species or other life stages that are more sensitive
than the earliest life-cycle stages of the rainbow trout. The data base for
saltwater species is limited to one test, and therefore, no statement can be
made concerning acute or chronic toxicity.

For the maximum protection of human health from the potential carcino-
genic effects  of exposure to chloroform through ingestion of contaminated
water and contaminated aquatic organisms, the ambient water concentra-
tions  should be zero, based on the nonthreshold assumption for this
chemical. However, zero level may not be attainable at the present time.
Therefore, the levels that may result in incremental increase of cancer risk
over the lifetime are estimated at 10 ,10"6, and 10" .
   Human health criteria were recalculated using Integrated Risk Infor-
mation System (IRIS) to reflect available data as  of 12/92 (57 F.R. 60848).
Recalculated IRIS values for chloroform are 5.7 ng/L for ingestion of con-
taminated water   and organisms  and 470  ng/L  for ingestion  of
contaminated aquatic organisms only. IRIS values are based on a 10"6 risk
level for carcinogens.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60848, December 22,1992)
                   See Appendix C for Human Health Methodology.
                                                                                69

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70

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                          2-CHLOROPHENOL
                                   CAS# 95-57-8
CRITERIA

Aquatic Life
Human Health
The available data for 2-chlorophenol indicate that acute toxicity to fresh-
water aquatic life occurs at concentrations as low as 4,380 ug/L and would
occur at lower concentrations among species that are more sensitive than
those tested. No definitive data are available concerning the chronic toxic-
ity  of 2-chlorophenol to sensitive  freshwater aquatic life, but  flavor
impairment  occurs in one species of fish at concentrations as low  as
2,000 ug/L.
   No saltwater organisms have been tested with 2-chlorophenol, and
therefore, no statement can be made concerning acute or chronic toxicity.

Human health criteria were recalculated using Integrated Risk Informa-
tion  System (IRIS) to reflect available data as of 12/92 (57 F.R. 60890).
Recalculated IRIS values for 2-chlorophenol are 120 ug/L for ingestion of
contaminated water and organisms and 400 ng/L for ingestion organisms
only. According to available organoleptic data, the estimated level is 0.1
Ug/L to control undesirable taste and odor qualities of ambient water. Or-
ganoleptic data do have limitations as a basis for  establishing a  water
quality criterion but do not have a  demonstrated relationship to poten-
tially adverse effects on human health.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60890, December 22,1992)
                   See Appendix C for Human Health Methodology.
                                                                                71

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72

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                CHLOROPHENOXY HERBICIDES
                        CAS# 2,4-D 94-75-7; 2,4,5-TP 93-72-1
CRITERIA
Rationale
2,4-D 100 ng/L for domestic water supply (health).
2,4,5-TP 10 ng/L for domestic water supply (health).

Two widely used herbicides are 2,4-D (2,4-dichlorophenoxy) acetic acid and
2,4,5-TP (silvex) 2-(2,4,5-trichlorophenoxy) propionic acid. These com-
pounds may exhibit different herbitidal properties, but all are hydolyzed
rapidly to the corresponding acid in the body.
    The subacute oral toxicity of chlorophenoxy herbicides has been inves-
tigated in  a number of animals. The dog  was found to be sensitive and
often displayed mild injury in response to doses of 10 mg/kg/day for 90
days and serious effects from doses of 20 mg/kg/day for 90 days. The no-
effect level of 2,4-D is 0.5 mg/kg/day in the rat and 8.0 mg/kg/day in the
dog.
                   Table 1.—Derivation of approval limits (AL) for chlorophenoxy herbicides.





Compound
2,4-D ....

2.4.5-TP...
LOWEST LONG
TERM LEVELS
WITH MINIMAL OR
NO EFFECTS

Species
Rat
Dog
Rat
Dog

mg/kg/day'
0.5
8.0
2.6
0.9

CALCULATED MAXIMUM SAFE
LEVELS FROM ALL
SOURCES OF EXPOSURE
Safety
factortX)
1/500
1/500
1/500
1/500

mg/kg/day
0.1
0.016
0.005
0.002

mg/man/day"
7.0
l.I2d
0.35
0. 14d-



WATER
% of
Safe level

20
20
AL
mg/lc

.1
0.01
                     'Assume weight of rai = 0.3 kg and of dog = 10 kg: assume average daily food consumption of rat = 0.05 kg
                      and of dog = 0.2 kg.
                     "Assume average weight of human adult = 70 kg.
                     c Assume average daily intake of water for man — 2 liters.
                     •"Chosen as basis on which to derive AL. •
                       Table 1 illustrates the derivation of the criteria for the two chlorophe-
                   noxy herbicides. The long-term, no-effect levels (mg/kg/day) are listed for
                   the rat and the dog. These values are adjusted by a factor of 1/500 for 2,4-
                   D and 2,4,5-TP. The safe levels are then readjusted to reflect total allowable
                   intake per person. Since little 2,4-D or 2,4,5-TP is  expected to occur in
                   foods, 20 percent of the safe exposure level can reasonably be allocated to
                   water without jeopardizing the health of the consumer.
                    (Quality Criteria for Water, July 1976) PB-263943
                    See Appendix D for Methodology.
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74

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                             CHLORPYRIFOS
                                   CAS# 2921-88-2
CRITERIA

Aquatic Life
Summary
                   Freshwater —  4-day average of 0.041 ng/L
                                 1-hour average of 0.083 jxg/L
                   Saltwater —   4-day average of 0.0056 ng/L
                                 1-hour average of 0.011 (ig/L
                   The  acute values for 18 freshwater species in 15 genera range  from
                   0.11 ng/L for an amphipod to greater than 806 ng/L for 2 fishes and a
                   snail. The bluegill is the most sensitive fish species with an acute value of
                   10 ng/L, but 7 intervetebrate genera are more sensitive. Smaller organisms
                   seem to be more acutely sensitive than larger ones.
                      Chronic toxicity data are available for 1 freshwater species, the fathead
                   minnow. Unacceptable effects occurred in second generation larvae at 0.12
                   Hg/L, which was the lowest concentration tested. The resulting acute-
                   chronic ratio was greater than 1,417.
                      Little information is available on the toxicity of chlorpyrifos to fresh-
                   water plants, although algal blooms  frequently follow field applications.
                   The only available bioconcentration test on chlorpyrifos with a freshwater
                   species (the fathead minnow) resulted in  a bioconcentration factor of 1,673.
                      The acute toxicity of chlorpyrifos has been determined for 15 species of
                   saltwater animals in 12 genera with the acute values ranging  from 0.01
                   Hg/L for the Korean shrimp, Palaemon macrodactylus, to 1,911 fig/L for lar-
                   vae of the eastern oyster, Crassostrea virginica. Arthropods are particularly
                   sensitive to chlorpyrifos. Among the  10 species of fish tested, the 96-hour
                   LCSOs range from 0.58 ng/L for striped bass to 520 jxg/L for gulf toadfish.
                   Fish larvae are more sensitive than other life stages. Growth of the mysid,
                   Mysidopsis bahia, was reduced at 0.004 ng/L in a life-cycle test. In early life-
                   stage tests, the California grunion, Leuresthes tenuis, was the most sensitive
                   of the six  fishes, with growth being  reduced at 0.30 [ig/L. Of  the seven
                   acute-chronic ratios that have been determined with saltwater species, the
                   five lowest range from 2.388 to 12.50, whereas the highest is 228.5,
                      Concentrations of chlorpyrifos affecting six species of saltwater phyto-
                   plankton range from 138 to 10,000 ng/L. Bioconcentration factors (BCFs)
                   ranged from 100 to 5,100 when the gulf toadfish was exposed to concentra-
                   tions increasing from 1.4 to 150 ng/L. Steady-state BCFs averaged from
                   100 to 757 for five fishes exposed in early life-stage tests.

National Criteria The procedures described in the "Guidelines for Deriving Numerical Na-
                   tional Water Quality Criteria for the Protection  of Aquatic Organisms and
                   Their Uses"  indicate that, except possibly where a locally important spe-
                   cies is very sensitive, freshwater aquatic organisms and their uses should
                   not be affected unacceptably if the  four-day average concentration of
                   chlorpyrifos does not exceed 0.041 ng/L  more than once every three years

                                                                                 75

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                  on the average, and if the one-hour average concentration does not exceed
                  0.083 ng/L more than once every three years on the average.
                     The procedures described in the guidelines also indicate that, except
                  possibly where a locally important species is very sensitive, saltwater
                  aquatic  organisms and their uses should not be affected unacceptably if
                  the four-day average concentration of chlorpyrifos does not exceed 0.0056
                  Hg/L more than once every three years on the average, and if the one-hour
                  average concentration does not exceed 0.011 jAg/L more than once every
                  three years on the average.
                     In the Agency's best scientific judgment,  three years is the  average
                  amount of time aquatic ecosystems should be provided between excur-
                  sions. .The resiliences  of ecosystems and their abilities to recover differ
                  greatly, however, and site-specific allowed excursion frequencies can be es-
                  tablished if adequate justification is provided.
                     When designing waste  treatment facilities, criteria for developing
                  water quality-based permit limits must be applied to an appropriate was-
                  teload allocation model. Dynamic models are preferred for the application
                  of these criteria. Limited data or other considerations might make their use
                  impractical, in which case one must rely on a steady-state model.
                  (51 F.R. 43665, December 3,1986)
                  See Appendix A for Aquatic Life Methodology.
76

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                                 CHROMIUM
CRITERIA
Aquatic Life      Chromium (VI) Freshwater — 4-day average of 11 |ig/L
                                              1-hour average of!6 jig/L
                                  Saltwater —  4-day average of 50 ng/L
                                              1-hour average of 1,100 ng/L

Summary

Chromium (VI) 18540299
                   Acute toxicity values for chromium (VI) are available for freshwater ani-
                   mal species in 27 genera and range from 23.07 ng/L for a cladoceran to
                   1,870,000 ng/L for a stonefly. These species include a wide variety of ani-
                   mals that perform a spectrum  of ecological functions. All five tested
                   species of daphnids are especially sensitive. The few data that are available
                   indicate that the acute toxicity of chromium (VI) decreases as hardness and
                   pH increase.
                       The chronic value for both rainbow trout and brook trout is 264.6 mg/L,
                   which is much lower than the chronic value of 1,987 jig/L for the fathead
                   minnow. The acute-chronic ratios for these three fishes range from 18.55 to
                   260.8. In all three chronic tests, a temporary  reduction in growth occurred
                   at low concentrations. Six chronic tests with  five species of daphnids gave
                   chronic values that range from 2.5 to 40 ng/L; the acute-chronic ratios
                   range from 1.130 to 9.680. Except for the fathead minnow, all the chronic
                   tests were conducted in soft water.  Green algae are quite  sensitive to chro-
                   mium (VI). The bioconcentration factor obtained with rainbow trout is less
                   than 3. Growth of chinook salmon  was reduced at a measured concentra-
                   tion of 16 ng/L.
                       The acute toxicity of chromium (VI) to 23 saltwater vertebrate and in-
                   vertebrate species ranges from 2,000 ng/L for a polychaete  worm and a
                   mysid to 105,000 ng/L  for the mud snail. The chronic values for a poly-
                   chaete range from 13 to 36.74 ng/.L, whereas that for a mysid is 132 ng/L.
                   The acute-chronic ratios range from 15.38 to 238.5. Toxicity to macroalgae
                   was reported at 1,000 and 5,000 ng/L. Bioconcentration factors for chro-
                   mium (VI) range from 125 to 236 for bivalve  molluscs and polychaetes.

Chromium (III) 1308-14-1
                   Acute values for chromium (III) are available for 20 freshwater animal spe-
                   cies in 18 genera ranging from 2,221 ng/L for a mayfly to 71,060 ng/L for a
                   caddisfly. Hardness has a significant influence on toxicity, with chromium
                   (III) being more toxic in soft water.
                       A life-cycle test with Daphnia magna in soft water gave a chronic value
                   of 66 ng/L. In a comparable test in hard water, the lowest test concentra-
                   tion of 44 jxg/L inhibited reproduction of D. magna,  but this effect may
                   have resulted from  ingested precipitated chromium. In a life-cycle test
                   with the fathead minnow in hard water, the chronic value was 1,025 ng/L.

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                       Toxicity data are available for only two freshwater plant species: a con-
                   centration  of  9,900  ng/L  inhibited  growth  of roots  of  Eurasian
                   watermilfoil, and a freshwater green alga was affected by a concentration
                   of 397 ng/L in soft water. No bioconcentration factor has been measured
                   for chromium (HI) with freshwater organisms.
                       Only two acute values are available for chromium (III) in saltwater
                   10,300 ng/L for the eastern oyster and 31,500 (ig/L for the mummichog. In
                   a chronic test, effects were not observed on a polychaete worm at 50,400
                   Hg/L at pH=7.9, but acute lethality occurred at pH=4.5. Bioconcentration
                   factors for saltwater organisms and chromium (III) range from 86 to 153,
                   similar to the bioconcentration factors for chromium (VI) and saltwater
                   species.
NATIONAL CRITERIA
Aquatic Life

Chromium (VI)
Chromium (III)
                   The procedures described in the "Guidelines for Deriving Numerical Na-
                   tional Water Quality Criteria for the Protection of Aquatic Organisms and
                   Their Uses" indicate that, except possibly where a locally important spe-
                   cies is very sensitive, freshwater aquatic organisms and their uses should
                   not be affected unacceptably if the four-day average concentration of chro-
                   mium (VI) does not exceed 11 ng/L more than once every three years on
                   the average, and if the one-hour average concentration does not exceed 16
                   Hg/L more than once every three years on the average.
                       The procedures described in the guidelines indicate that, except possi-
                   bly where a locally important species is very sensitive, saltwater aquatic
                   organisms and their uses should not be affected unacceptably if the four-
                   day average concentration of chromium (VI) does  not exceed 50  ng/L
                   more than once every three years on the average, and if the one-hour aver-
                   age concentration does not exceed 1,100 ng/L more than once every three
                   years on the average. Data  suggest that the acute toxicity of chromium (VI)
                   is salinity dependent; therefore, the one-hour average concentration might
                   be underprotective at low salinities.
                   The procedures described in the guidelines indicate that, except possibly
                   where a locally important species is very sensitive, freshwater aquatic or-
                   ganisms and their uses should not be affected unacceptably if the four-day
                   average concentration (in jig/L) of chromium (III) does not exceed the nu-
                   merical value given by
                                          _(0.8190pn(hardness)]+1.561)
                                          6
                   more than once  every three years on the average, and if the one-hour
                   average concentration (in ng/L)  does not exceed  the numerical value
                   given by
                                          _ (0.8190[ln(hardness)]+3.688)
                                          c
                   more  than once every three years on the average. For example, at
                   hardnesses of 50,  100, and 200 mg/L as CaCOa, the four-day average
                   concentrations of chromium (III) are 120, 210, and 370 ng/L, respectively,
                   and the one-hour average concentrations are 980,1,700, and 3,100 ng/L.
 78

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                       No saltwater criterion can be derived for chromium (III), but 10,300
                   Hg/L is the EC50 for eastern oyster embryos, whereas 50,400 ng/L did not
                   affect a polychaete worm in a life-cycle test.
                       The recommended exceedence frequency of three years is the Agency's
                   best scientific judgment of the average time needed for an unstressed sys-
                   tem to recover from a pollution event in which exposure to chromium
                   exceeds the criterion. For example, a stressed system (one in which several
                   outfalls occur in  a limited area) would be expected or require more time
                   for recovery. The resilience of ecosystems and their ability to recover differ
                   greatly, however, and site-specific criteria can be established if adequate
                   justification is provided.
                       In designing  waste treatment facilities, criteria must be applied to an
                   appropriate  wasteload allocation model; dynamic models are preferred.
                   Limited data or other factors may make use of these models impractical, in
                   which case one should rely on a steady-state model. The Agency recom-
                   mends the  interim use  of  1Q5 for  1Q1O  for  Criterion  Maximum
                   Concentration design flow and 7Q5 or 7Q1O for the Criterion Continuous
                   Concentration design  flow in  steady-state  models for unstressed and
                   stressed systems, respectively. These matters  are discussed in more detail
                   in EPA's  "Technical Support  Document for  Water Quality-Based Toxics
                   Control."

Human Health    Human health criteria have been withdrawn for this compound (see 57
                   F.R. 60885, December 22, 1992).  Although the human health criteria are
                   withdrawn, EPA  published a document for this compound that may con-
                   tain useful  human  health information. This document was originally
                   noticed in 45 F.R. 79331, November 28,1980.
                   (45 F.R. 79318 November 28,1980) (50 F.R. 30784, July 29,1985)
                   (57 F.R. 60848, December 22,1992)
                   See Appendix A for Aquatic Life Methodology.
                                                                                 79

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80

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                                    COLOR
CRITERIA
Introduction
   • For aesthetic purposes, waters shall be virtually free from
     substances producing objectionable color;

   • The source of supply should not exceed 75 color units on the
     platinum-cobalt scale for domestic water supplies; and

   • Increased color (in combination with turbidity) should not reduce
     the depth of the compensation point for photosynthetic activity by
     more than 10 percent from the seasonally established norm for
     aquatic life.

Degradation processes in the natural environment are the principal con-
tributors to color  in water. Although colloidal forms  of iron and
manganese occasionally color water, the most common causes of color in
water are complex organic compounds originating from the  decomposi-
tion  of  naturally  occurring  organic matter.  Sources of organic matter
include  materials in  the soil that were generated by humans such as tan-
nins, human acid, humates, and decayed material from plankton and other
aquatic  plants. Industrial discharges may contribute similar compounds
from, for example, the pulp and paper and tanning industries. Other in-
dustrial discharges, such as those  from certain  textile and chemical
processes, may contain brightly colored substances (see Table 1).

Table 1.—Maximum color of surface waters that have been used as industrial water
supplies.
INDUSTRY OR INDUSTRIAL USE
Boiler makeup water 	 	 	
Cooling water 	
Pulp and paper water . 	 	
Chemical and allied products water
Petroleum products water ... ...

COLOR UNITS
1.200
1.200
360
500
•>5

                       Surface  waters  may appear colored because of suspended matter,
                   which comprises turbidity. Such color is referred to as "apparent color"
                   and is differentiated from true color caused by colloidal human materials.
                   Natural color is reported in color "units" that generally are determined by
                   the platinum-cobalt method.
                       No general agreement exists as to the chemical composition of natural
                   color, and in fact, the composition  may vary chemically from place to
                   place. Examined color-causing colloids have been characterized as aro-
                   matic, polyhydroxy, methoxy carboxylic acids. Color-causing constituents
                   were characterized as being dialyzable and composed of aliphatic, polyhy-
                   droxyl carboxylic acids with molecular weights varying from less than 200
                   to approximately 400. The colloidal fraction of color exists in the 3.5 to 10
                   mu diameter range. Other characteristics of color observed in laboratory
                   studies of natural waters were summarized as follows: color is caused by

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                   light scattering and fluorescence rather than absorption of light energy,
                   and pH affects both particle size of the color-causing colloids and the in-
                   tensity of color itself.
                   (Quality Criteria for Water, July 1976) PB-263943
                   See Appendix D for Methodology.
82

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CRITERIA
                                   *COPPER
                                   CAS# 7440-50-8
Aquatic Life       Not to exceed 2.9 ng/L in salt water.
                    Freshwater criteria are hardness dependent. See text.

Summary         Acute toxicity data are available for species in 41 genera of freshwater ani-
                    mals. At a hardness of 50 mg/L, the genera range in sensitivity from 16.74
                    Hg/L for Ptychocheilus to 10,240 ng/L for Acroneuria. Data for eight species
                    indicate that acute toxicity decreases as hardness increases. Additional
                    data for several species  indicate that toxicity also decreases with increases
                    in alkalinity and total organic carbon.
                       Chronic values available for 15 freshwater species range from 3.873
                    ug/L for brook trout to 60.36 jig/L for northern pike. Fish and invertebrate
                    species seem to be almost equally sensitive to the chronic toxicity of cop-
                    per.
                       Toxicity tests on copper conducted with a wide  range of freshwater
                    plants indicate sensitivities similar to those of animals. Complexing effects
                    of the test media and a lack of good analytical data make it difficult to inter-
                    pret and apply these results. Protection of animal species, however, appears
                    to offer adequate plant protection. Bioconcentrations of copper are light in
                    edible portion of freshwater aquatic species.
                       Saltwater animals' acute sensitivities to copper range from 5.8 ng/L for
                    the blue mussel to 600 ng/L for the green crab.^A chronic life-cycle test has
                    been conducted with a mysid; adverse effects were observed at 77 ng/L
                    but not at 38 u.g/L, which resulted in an acute-chronic ratio of 3.346. Sev-
                    eral saltwater algal species have been tested, and effects were  observed
                    between 5 and 100 ng/L. Oysters can bioaccumulate  copper up to 28,200
                    times and become bluish green, apparently  without significant mortality.
                    In long-term exposures, the bay scallop was killed at 5 ng/L.

National Criteria  The procedures described in the "Guidelines for Deriving Numerical Na-
                    tional Water Quality Criteria for the Protection of Aquatic Organisms and
                    Uses" indicate that — except possibly where a locally important species is
                    very sensitive — freshwater aquatic organisms and their uses should not
                    be affected unacceptably if the four-day average concentration (in ng/L) of
                    copper does not exceed the numerical value given by
                                           Q(0.8545[ln{hardness)l-1.465)
                                           G
                    more than once  every  three years on the average, and if the  one-hour
                    average concentration  (in  ng/L) does  not  exceed the  numerical  value
                    given by
                                           e
                                            (0.9422[ln(hardness)]-1.464)
                    'Indicates suspension, cancelation, or restriction by U.S. EPA Office of Pesticides and
                     Toxic Substances.
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                    more than  once every three years on  the average.  For example, at
                    hardnesses  of 50, 100, and 200  mg/L as CaCOj, the four-day average
                    concentrations of copper are 6.5, 12, and 21 ng/L, respectively, and the
                    one-hour average concentrations are 9.2,18, and 34 ug/L.
                       The procedures described in the guidelines indicate that, except possi-
                    bly where a locally important species is very sensitive, saltwater aquatic
                    organisms and their uses should not be affected unacceptably if the one-
                    hour average concentration of copper does not exceed 2.9 ug/L more than
                    once every three years on the average.
                       The recommended exceedence frequency of three years is the Agency's
                    best scientific judgment of the average time needed for an unstressed sys-
                    tem to recover from a pollution event in which exposure to copper exceeds
                    the criterion. For example, a stressed system (one in which several outfalls
                    occur in a limited area) would be expected to require more time for recov-
                    ery. The resilience of ecosystems  and their ability to recover differ greatly,
                    however, and site-specific criteria can be established if adequate justifica-
                    tion is provided.
                       In developing waste treatment facilities, criteria requires the selection
                    of an appropriate wasteload allocation model. Dynamic models are pre-
                    ferred for the application of these criteria. Limited data or other factors
                    may make their use impractical, in which case one should rely on a steady-
                    state model. The Agency recommends the interim use of 1Q5 or 1Q1O for
                    Criterion Maximum Concentration design flow and 7Q5 or 7Q1O for the
                    Criterion Continuous Concentration design  flow in steady-state models
                    for unstressed and stressed systems respectively. These matters are dis-
                    cussed in more  detail in EPA's "Technical Support Document for Water
                    Quality-Based Toxics Control."

Human Health     Human health criteria were recalculated  using Integrated Risk Informa-
                    tion System (IRIS) to reflect available data as  of 12/92 (57 F.R. 60890). The
                    recalculated IRIS values for copper is 1,300 ug/L for ingestion of contami-
                    nated  water and  organisms. Using  available organoleptic data,  the
                    estimated level is 1  mg/L for controlling undesirable taste and odor qual-
                    ity of ambient water. Organoleptic data as a basis for establishing a water
                    quality  criteria have limitations and no demonstrated relationship to po-
                    tentially adverse effects on human health.
                    (45 F.R. 79318 November 28,1980) (50 F.R. 30784, July 29,1985)
                    (57 F.R. 60890, December 22,1992)
                    See Appendix A for Aquatic Life Methodology.
                    See Appendix C for Human Health Methodology.
 84

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CRITERIA
                                   CYANIDE
                                   CAS# 57-12-5
Aquatic Life
Summary
Freshwater — 4-day average of 5.2
             1-hour average of 22 ug/L
Saltwater—  1-hour average of 1.0 (ig/L

Data on the acute toxicity of free cyanide (the sum of cyanide present as
HCN and CN-, expressed as CN) are available for a wide variety of fresh-
water species that are involved in diverse community functions. In tests,
the acute sensitivities ranged from 44.73 ng/L to 2,490 ng/L, but all of the
species with acute sensitivities above 400 ng/L were invertebrates. A long-
term survival and a partial and life-cycle test with fish gave chronic values
of 13.57, 7.849, and 16.39 ug/L, respectively. Chronic values for two fresh-
water invertebrate species were 18.33 and 34.06 ug/L. Freshwater plants
were affected at cyanide concentrations ranging from 30 ng/L to 26,000
                       Free cyanide's acute toxicity to saltwater species ranged from 4.893
                         to 10,000 ng/L; invertebrates were both the most and least sensitive
                   species. In an early life-stage test with the sheepshead minnow, long-term
                   survival gave a chronic value of 36.12 ng/L. Long-term survival in a mysid
                   life-cycle test resulted in a chronic value of 69.71 ng/L. Tests with the red
                   macroalga, Champia parvula, showed cyanide toxicity at 11 to 25 ng/L, but
                   other species were affected at concentrations up to 3,000 jig/L.

National Criteria The procedures described in the "Guidelines for Deriving Numerical Na-
                   tional Water Quality Criteria for the Protection of Aquatic Organisms and
                   Their Uses" indicate  that, except possibly where a locally important spe-
                   cies is very sensitive, freshwater aquatic organisms and their uses should
                   not be affected unacceptably if the four-day average concentration of cya-
                   nide does not exceed 5.2 ng/L more than once every three years on the
                   average, and if the one-hour average concentration does not exceed 22
                   Hg/L more than once every three years on the average.
                       The procedures described in the guidelines indicate that, except possi-
                   bly where a locally important species is very sensitive, saltwater aquatic
                   organisms and their uses should not be affected unacceptably if the one-
                   hour average concentration of cyanide does not exceed 1.0 ug/L more than
                   once every three years on the average.
                       EPA believes that a measurement such as free cyanide would provide a
                   more scientifically correct basis upon which to establish criteria for cya-
                   nide.  The criteria were developed on this basis. However, at this time EPA
                   has approved no methods for such a measurement to implement the crite-
                   ria through Agency and State regulatory programs.
                       The recommended exceedence frequency of three years is the Agency's
                   best scientific judgment of the average amount of time it will take an un-
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                    stressed system to recover from a pollution event in which exposure to
                    cyanide exceeds the criterion. A stressed system, for example — one in
                    which several outfalls occur in a limited area — would be expected to re-
                    quire more time for recovery. The resilience of ecosystems and their ability
                    to recover differ greatly, however, and site-specific criteria may be estab-
                    lished if adequate justification is provided.
                       In designing waste treatment facilities, criteria must be applied to an
                    appropriate wasteload allocation model; dynamic models are preferred.
                    Limited data or other factors may make use of these models impractical, in
                    which case one should rely on a steady-state model. The Agency recom-
                    mends  the  interim  use  of 1Q5  or  1Q1O  for Criterion Maximum
                    Concentration design flow and 7Q5 or 7Q1O for the Criterion Continuous
                    Concentration  design  flow in steady-state models for unstressed and
                    stressed systems, respectively. These matters are discussed in more detail
                    in EPA's "Technical  Support Document for Water Quality-Based Toxics
                    Control."

Human Health     Published human health criteria were recalculated using Integrated Risk
                    Information  System  (IRIS) to  reflect  available data  as  of  12/92
                    (57 F.R. 60911). Recalculated IRIS values for cyanide are 700  ng/L for in-
                    gestion  of contaminated water and  organisms  and 220,000 ng/L for
                    ingestion of contaminated aquatic organisms only.
                    (45 F.R. 79318 November 28,1980) (50 F.R. 30784, July 29,1985)
                    (57 F.R. 60911, December 22,1992)
                    See Appendix A for Aquatic Life Methodology.
                    See Appendix C for Human Health Methodology.
 86

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                      DDT AND  METABOLITES
                                   CAS# 72-54-8
CRITERIA

Aquatic Life


DDT
TDE
DDE
Human Health
24-hour average for freshwater and saltwater is 0.001 ng/L .
Not to exceed at anytime 1.1 ng/L in fresh water or 0.13 ng/L in salt water.

The criterion for DDT and its metabolites to protect freshwater aquatic life
as derived using the guidelines is 0.0010 jig/L as a 24-hour average. The
concentration should not exceed 1.1 jig/L at any time.
    The criterion for DDT and its metabolites to protect saltwater aquatic
life as derived using the guidelines is 0.0010 ng/L as a 24-hour average.
The concentration should not exceed 0.13 ng/L at any time.

The  available data for TDE  indicate  that acute toxicity to freshwater
aquatic life occurs at concentrations as low as 0.6 ng/L and would occur at
lower concentrations among species that are more sensitive than  those
tested. No data are available concerning TDE's chronic toxicity to sensitive
freshwater aquatic life.
   The available data for TDE indicate that acute toxicity to saltwater
aquatic life occurs at concentrations as low as 3.6 ng/L and would occur at
lower concentrations among species that are more sensitive than  those
tested. No data are available concerning TDE's chronic toxicity to sensitive
saltwater aquatic life.

The  available data for DDE indicate  that acute  toxicity to freshwater
aquatic life occurs at concentrations as low as 1,050 fig/L and would occur
at lower concentrations among species  that are more sensitive than those
tested. No data are available concerning DDE's chronic toxicity to sensitive
freshwater aquatic life.
   The available data for DDE indicate that acute toxicity to saltwater
aquatic life occurs in concentrations as low as 14 ng/L and would occur at
lower concentrations among species that are more sensitive than  those
tested. No data are available concerning DDE's chronic toxicity to sensitive
saltwater aquatic life.

The  ambient water concentration should be zero, based  on the nonthre-
shold assumption for this chemical, for  the maximum protection of human
health from the potential carcinogenic effects of exposure  to DDT through
ingestion of contaminated  water and  contaminated aquatic organisms.
However, zero level may not be attainable at the present  time. Therefore,
the levels that may result in incremental increase of cancer risk over a life-
time are estimated at 10"5,10"6, and 10"7.
   Human health criteria were recalculated using Integrated Risk  Infor-
mation System (IRIS) to reflect available data as of 12/92 (57 F.R. 60848).
The  recalculated IRIS value for DDT is  0.00059 ug/L for both ingestion of
                                                                               87

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water and organisms, and ingestion of contaminated aquatic organisms
only. IRIS values are based on a 10  risk level for carcinogens.
   The recalculated IRIS value for IDE is 0.00083 ng/L for both ingestion
of contaminated water and organisms  and for ingestion of contaminated
aquatic organisms only.
   The recalculated IRIS value for DDE is 0.00059 ng/L for both ingestion
of contaminated water and organisms  and for ingestion of contaminated
aquatic organisms only.
(45 F.R. 79318, November 28,1980) (57 F.R. 60848, December 22,1992)
See Appendix 8 for Aquatic Life Methodology.
See Appendix C for Human Health Methodology.

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                                  DEMETON
                                  CAS# 8065-48-3
CRITERIA

Aquatic Life

Rationale
0.1 ng/L for both freshwater and saltwater aquatic life.

Static LC50 bioassays yielded toxicity values for the phosphorus pesticide
demeton and for carp, goldfish, fathead minnow, channel catfish, guppy,
rainbow trout, and bluegill ranging from 70 ng/L to 15,000 jig/L. These
tests demonstrate a sharp division in species sensitivity, with the bluegill,
Lepomis macrochirus; rainbow trout, Oncorhynchus mykiss;  and guppy,
Poecilia reticulata being susceptible to lower concentrations, while the re-
maining species were comparatively resistant.
   Bluegills with a 24-hour LC50 of 70 ng/L were the most sensitive fish.
Acute toxicity values reported for invertebrates range from 10 to 100,000
                       Static LC50 data for invertebrate Gammarus fasciatus yield 24- and 96-
                   hour LC50 values of 500 ng/L and 27 ng/L, respectively. Studies indicate
                   residual effects of AChE inhibition from exposure to demeton. The few
                   data on toxicity of demeton to marine organisms includes a 48-hour EC50
                   of 63 fig/L for the pink shrimp, Penaeus duorarum, and a 24-hour LC50 of
                   550 ng/L for the spot, Leiostomus xanthurus.
                       The criterion must be based partly on the fact that all organophos-
                   phates inhibit the production of the AChE enzyme. Demeton is unique,
                   however, in that the persistence of its  AChE-inhibiting ability is greater
                   than that of 10 other common organophosphates. Because such inhibition
                   may be additive with repeated exposures and may be compounded by any
                   of the organophosphates, it is recommended that a criterion for demeton
                   be based primarily on its enzyme-inhibiting potential. A criterion of 0.1
                   Hg/L demeton for freshwater and marine aquatic life is recommended,
                   since that concentration will not be expected to significantly inhibit AChE
                   over a long period. In addition, the criterion recommendation is in close
                   agreement with the criteria for the other organophosphates.


                   (Quality Criteria for Water, July 1976) PB-263943
                   See Appendix D for Methodology.
                   'Crustaceans and insect larvae were considerably more sensitive overall to demeton
                    than molluscs and tubifex worms.
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                        DICHLOROBENZENES
                                 CAS# 25321-22-6
CRITERIA
Aquatic Life      The available data for dichlorobenzenes indicate that acute and chronic
                   toxicity to freshwater aquatic life occur at concentrations as low as 1,120
                   and 763 ng/L, respectively, and would  occur  at lower concentrations
                   among species that are more sensitive than those tested.
                      The available data for dichlorobenzenes indicate that acute toxicity to
                   saltwater aquatic life occurs at concentrations as low as 1,970 ng/L and
                   would occur at lower concentrations among species that are more sensitive
                   than those tested. No data are available concerning the chronic toxicity of
                   dichlorobenzenes to sensitive saltwater aquatic life.

Human Health

1,2-Dichlorobenzene 95-50-1

                   For the maximum protection of human health from the potential effects of
                   exposure to 1,2-dichlorobenzene, the human health criteria were recalcu-
                   lated  using  the Integrated Risk Information System (IRIS) to  reflect
                   available information as of 12/92 (57 F.R. 60848). The recommended crite-
                   ria are 2,700 ng/L for ingestion  of contaminated water and organisms and
                   17,000 ng/L for ingestion of contaminated organisms only.

1,3-Dichlorobenzene 541-73-1

                   For the maximum protection of human health from the potential effects of
                   exposure to 1,3-dichlorobenzene, the recommended criteria are 400 ng/L
                   for ingestion of contaminated water and organisms and 2,600 ng/L for in-
                   gestion of contaminated organisms only.

1,4-Dichlorobenzene 106-46-7

                   For the maximum protection of human health from the potential effects of
                   exposure to 1,4-dichlorobenzene, the recommended criteria are 400 ng/L
                   for ingestion of contaminated water and organisms and 2,600 ng/L for in-
                   gestion of contaminated organisms only.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60848, December 22,1992)
                   See Appendix C for Human Health Methodology.
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                        DICHLOROBENZIDINE
                                   CAS# 91-94-1
CRITERIA

Aquatic Life
Human Health
The data base available for dichlorobenzidines and freshwater organisms
is limited to one test on bioconcentration of 3,3-dichlorobenzidine; there-
fore, no statement can be made concerning acute or chronic toxicity.
   No saltwater organisms have been tested with any dichlorobenzidine;
therefore, no statement can be made concerning acute or chronic toxicity.

For the maximum protection of human health from the potential carcino-
genic  effects  of exposure to dichlorobenzidine through ingestion of
contaminated water and contaminated aquatic organisms, the ambient
water concentrations should be zero, based on the nonthreshold assump-
tion for  this chemical. However, zero level may  not be attainable at the
present time. Therefore, the levels that may result in incremental increase
of cancer risk over a lifetime are estimated at 10~5,10"6, and 10~7.
   Human health criteria were  recalculated using Integrated Risk Infor-
mation System (IRIS) to reflect available data as of 12/92 (57  RR. 60848).
Recalculated IRIS values for 3,3-dichlorobenzidine are 0.04 ug/L for inges-
tion of contaminated water and organisms and 0.077 ng/L for ingestion of
contaminated aquatic organisms only. IRIS values are based on a 10  risk
level for carcinogens.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60848, December 22,1992)
                   See Appendix C for Human Health Methodology.
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                       DICHLOROETHYLENES
                                  CAS# 25323-30-3
CRITERIA
Aquatic Life      The available data for dichloroethylenes indicate that acute toxicity to
                   freshwater aquatic life occurs at concentrations as low as 11,600 ng/L and
                   would occur at lower concentrations among species that are more sensitive
                   than those tested. No definitive data are available concerning the chronic
                   toxicity of dichloroethylenes to sensitive freshwater aquatic life.
                      The  available data for dichloroethylenes  indicate  that acute  and
                   chronic toxicity to saltwater aquatic life occurs at concentrations as low as
                   224,000 ng/L and would occur at lower concentrations among species that
                   are more sensitive than those tested. No data are available concerning the
                   chronic toxicity of dichloroethylenes to sensitive saltwater aquatic life.

Human Health

1,1-Dichloroethylene 75-35-4

                   For the maximum protection of human health from the potential carcino-
                   genic effects of exposure to 1, 1-dichloroethylene through  ingestion of
                   contaminated water and contaminated  aquatic organisms,  the ambient
                   water concentrations should be zero, based on the nonthreshold assump-
                   tion for this chemical. However, zero  level may not be  attainable at the
                   present time. Therefore, the levels that may result in incremental increase
                   of cancer risk over the lifetime are estimated at 10  ,10 , and 10" .
                      Human health criteria were recalculated using Integrated Risk Infor-
                   mation System (IRIS) to reflect available data as of 12/92 (57 F.R. 60848).
                   Recalculated IRIS values for 1,1-dichloroethylene are 0.057 ng/L for inges-
                   tion of contaminated water and organisms and 3.2 fig/L for ingestion of
                   contaminated aquatic organisms only. IRIS values are based on  a 10"6 risk
                   level for carcinogens.

1,2-Dichloroethylene 156-60-5

                   Human health criteria were recalculated using IRIS to reflect available data
                   as of 12/92 (57 F.R.  60890). Recalculated IRIS values for 1,2-trans-dichlo-
                   roethylene  are  700  ng/L  for ingestion  of  contaminated water  and
                   organisms. IRIS values are based on a 10"6 risk level for carcinogens.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60890, December 22,1992)
                   See Appendix C for Human Health Methodology.
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                      2,4-DICHLOROPHENOL
                                  CAS# 120-83-2
CRITERIA

Aquatic Life
Human Health
The available data for 2,4-dichlorophenol indicate that acute and chronic
toxicity to freshwater aquatic life occurs at concentrations as low as 2,020
and 365 ng/L, respectively,  and would occur at lower concentrations
among species that are more sensitive than those tested. Mortality to early
life stages of one species of fish occurs at concentrations as low as 70 ng/L-
   Only one test has been conducted with saltwater organisms and 2,4-di-
chlorophenol, and therefore, no statement can be made concerning acute
or chronic toxicity.

Human health criteria were recalculated using Integrated Risk Informa-
tion System (IRIS) to  reflect available data as of 12/92 (57 F.R. 60848).
Recalculated IRIS  values for 2,4-dichlorophenol are 93.0 ng/L for ingestion
of contaminated water and organisms and 790 |xg/L for ingestion of con-
taminated aquatic organisms only.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60848, December 22,1992)
                   See Appendix C for Human Health Methodology.
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                        DrCHLOROPROPANE
                                CAS# 26638-19-7

                        DICHLOROPROPENE
                                CAS# 26952-23-8
CRITERIA

Aquatic Life
Human Health
The available data for dichloropropane indicate that acute and chronic tox-
icity to freshwater aquatic life occurs at concentrations as low as 23,000
and 5,700 \ig/L, respectively, and would occur at lower concentrations
among species that are more sensitive than those tested. Acute and chronic
toxicity to saltwater aquatic life occur at concentrations as low as 10,300
and 3,040 ng/L, respectively, and would occur at lower concentrations
among species that are more sensitive than those tested.
   The available data for dichloropropene indicate that acute and chronic
toxicity to freshwater aquatic life occurs at concentrations as low as 6,060
and 244 ng/L, respectively, and would occur at lower concentrations
among species that are more sensitive than those tested. Acute toxicity to
saltwater aquatic  life occurs at concentrations as low as 790 ng/L and
would occur at lower concentrations among species that are more sensitive
than those tested.  No data are available concerning the chronic toxicity of
dichloropropene to sensitive saltwater aquatic life.

Human health criteria were recalculated using Integrated Risk Informa-
tion System (IRIS) to reflect available data as of 12/92 (57 F.R. 60890).
Recalculated IRIS  values for 1,2-dichloropropane is 0.52 ng/L per inges-
tion of water and organisms  and 39.0 ng/L per ingestion of organisms
only.
   For the protection of human health from the toxic properties of dichlo-
ropropenes ingested through water and contaminated aquatic organisms,
the ambient water criterion is 87 ng/L.
   For the protection of human health from the toxic properties of dichlo-
ropropenes ingested through  contaminated aquatic organisms alone, the
ambient water criterion is 14.1 mg/L.
                  (45 F.R. 79318, November 28,1980) (57 F.R. 60890, December 22,1992)
                  See Appendix C for Human Health Methodology.
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                                  DIELDRIN
                                   CAS# 60-57-1
CRITERIA

Aquatic Life
Human Health
Freshwater — 24-hour average of 0.0019
             Never to exceed 2.5 ug/ L
Saltwater —  24-hour average of 0.0019 jig/ L
             Never to exceed 0.71 ng/L
   To protect freshwater aquatic life, the criterion for dieldrin is 0.0019
ug/L as a 24-hour average. The concentration should not exceed 2.5 ng/L
at any time.
   To protect saltwater aquatic life, the criterion as  derived using the
guidelines is 0.0019 ng/L as a 24-hour average. The concentration should
not exceed 0.71 ng/L at any time.

For the maximum protection of human  health from the potential carcino-
genic effects of exposure to  dieldrin through ingestion of contaminated
water and contaminated aquatic organisms, the ambient water concentra-
tion  should be zero, based on the nonthreshold  assumption  for  this
chemical. However, zero level may not  be attainable at the present time.
Therefore, the levels that may result in incremental increase of cancer risk
over the lifetime are estimated at 10"5,10"6, and 10"7.
   Human health criteria were recalculated using Integrated Risk Infor-
mation System (IRIS) to reflect available data as of 12/92 (57 F.R. 60848).
Recalculated IRIS values for dieldrin are 0.00014 ng/L for ingestion of con-
taminated water and organisms and also for ingestion of contaminated
aquatic organisms only. IRIS values are  based on a 10"6 risk level for car-
cinogens.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60848, December 22,1992)
                   See Appendix B for Aquatic Life Methodology.
                   See Appendix C for Human Health Methodology.
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                       2,4-DIMETHYLPHENOL
                                  CAS# 105-67-9
CRITERIA

Aquatic Life
Human Health
The available data for 2,4-dimethylphenol indicate that acute toxicity to
freshwater aquatic life occurs at concentrations as low as 2,120 ng/L and
would occur at lower concentrations among species that are more sensitive
than those tested. No data are available concerning the chronic toxicity of
dimethylphenol to sensitive freshwater aquatic life.
   No saltwater organisms have been tested with 2,4-dimethylphenol,
and therefore, no statement can be made concerning acute or chronic toxic-
ity.

Human health  criteria were recalculated using Integrated Risk Informa-
tion System (IRIS) to reflect data available  as of 12/92 (57 F.R. 60890).
Recalculated IRIS values for 2,4-dimethylphenol are 540 ng/L for ingestion
of contaminated water and organisms and 2,300 ng/L for ingestion of con-
taminated organisms only.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60890, December 22,1992)
                   See Appendix C for Human Health Methodology.
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CRITERIA
                           DINITROTOLUENE
                                 CAS# 25321-14-6
Aquatic Life
Human Health
The available data for 2,4-dinitrotoluene indicate that acute and chronic
toxicity to freshwater aquatic life occurs at concentrations as low as 330
and 230  ng/L,  respectively, and would occur at  lower concentrations
among species that are more sensitive than those tested.
   The available data for 2,4-dinitrotoluene indicate that acute toxicity to
saltwater aquatic life occurs at concentrations as low as 590 ug/L and
would occur at lower concentrations among species that are more sensitive
than those tested. No data are available concerning  the chronic toxicity of
dinitrotoluenes to sensitive saltwater aquatic life but a decrease in algal
cell numbers occurs at concentrations as low as 370 ng/L.
2,4-Dinitrotoluene 121-14-2
                   For the maximum protection of human health from the potential carcino-
                   genic effects  of exposure to 2,4-dinitrotoluene  through ingestion  of
                   contaminated water and contaminated aquatic organisms, the  ambient
                   water concentration should be zero, based on the nonthreshold assump-'
                   tion for this chemical. However, zero level may not be attainable at the
                   present time. Therefore, the levels that may result in incremental increase
                   of cancer risk over a lifetime are estimated at 10"5,10"6, and 10"7. The corre-
                   sponding recommended criteria are 1.1 ng/L, 0.11 ug/L, and 0.011 ng/L,
                   respectively. If these estimates are made for consumption of aquatic organ-
                   isms only, excluding consumption of water, the levels  are 91 ug/L, 9.1
                        , and 0.91 ug/L, respectively.
                   (45 F.R. 79318, November 28,1980)
                   See Appendix C for Human Health Methodology.
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                       DIPHENYLHYDRAZINE
                                  CAS# 122-66-7
CRITERIA       	


Aquatic Life

1,2-Diphenylhydrazine
                   The available data for 1,2-diphenylhydrazine indicate that acute toxicity to
                   freshwater aquatic life occurs at concentrations as low as 270 ng/L and
                   would occur at lower concentrations among species that are more sensitive
                   than those tested. No data are available concerning the chronic toxicity of
                   1,2-diphenylhydrazine to sensitive freshwater aquatic life.
                      No saltwater organisms have been tested with 1,2-diphenylhydrazine,
                   and therefore, no statement can be made concerning its acute or chronic
                   toxicity.

Human Health    For the maximum protection of human health from the potential carcino-
                   genic  effects  of  exposure to diphenylhydrazine through ingestion of
                   contaminated water and contaminated aquatic organisms, the ambient
                   water concentrations should be zero, based on the nonthreshold assump-
                   tion for this chemical. However, zero level may not be attainable at the
                   present time. Therefore, the levels that may result in incremental increase
                   of cancer risk over a lifetime are estimated at 10", 10 , and 10"  . The corre-
                   sponding recommended criteria  are  422  ng/L, 42  ng/L, and 4 ng/L,
                   respectively. If these estimates are made for consumption of aquatic organ-
                   isms only, excluding consumption of water, the levels are 5.6 ng/L, 0.56
                   ng/L, and 0.056 ng/L, respectively.
                      Published human health criteria were recalculated  using Integrated
                   Risk Information System (IRIS)  to reflect available data as of 12/92
                   (57  E.R. 60913). Recalculated IRIS values  for 1,2-diphenylhydrazine are
                   0.040 ng/L for ingestion of contaminated water and organisms and 0.54
                   ng/L for ingestion of contaminated aquatic organisms only. IRIS values are
                   based on a 10"6 risk level for carcinogens.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60913, December 22,1992)
                   See Appendix C for Human Health Methodology.
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CRITERIA

Aquatic Life
               DI-2-ETHYLHEXYL PHTHALATE
                                CAS# 117-81-7
The procedures described in the "Guidelines for Deriving Numerical Na-
tional Water Quality Criteria for the Protection of Aquatic Organisms and
Their Uses" do not allow for the derivation of national criteria for di-2-
ethylhexyl phthalate (DEHP), based on the available test information.
   Limited data indicate that acute toxicity occurs to freshwater aquatic
life at a concentration as low as 2,000 ng/L, which is above the reported
solubility limit for DEHP. Chronic toxicity occurs to one freshwater species
at a concentration as low as 160 ng/L.
   Toxicity data for DEHP and saltwater life is limited. However, if their
chronic sensitivity to DEHP is similar to that of freshwater aquatic life, ad-
verse effects on individual species might be expected at s!60 ug/L. An
ecosystem  process, ammonia  flux, has been shown to be reduced at
15.5 ng/L in summer months.
Human Health    Refer to phthalate esters.
                  (60 F.R. 49602, September 26,1995)
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                          DISSOLVED  OXYGEN
                                    CAS# 7782-44-7
National
Criteria
                    The national criteria for ambient dissolved oxygen concentrations for the
                    protection of freshwater aquatic life are presented in Table 1. The criteria
                    are derived from the production impairment estimates that are based pri-
                    marily upon growth data and information on temperature, disease, and
                    pollutant stresses. The average dissolved oxygen concentrations selected
                    are values 0.5 mg/L above the slight production impairment values and
                    represent values between no  production impairment and slight produc-
                    tion impairment. Each criterion may thus be viewed as an estimate of the
                    threshold concentration below which detrimental effects are expected.

                    Table 1.—Water quality criteria for ambient dissolved oxygen concentration.

30 Day Mean
7 Day Mean 	
7 Day Mean Minimum
1 Day Minimum4-5 	
COLDWATER CRITERIA
EARLY LIFE OTHER LIFE
STAGES1-2 STAGES
NA3
9.5 (6.5)
NA
8.0 (5.0)
6.5
NA
5.0
4.0
WARMWATER CRITERIA
EARLY LIFE OTHER LIFE
STAGES1 STAGES
NA
6.0
NA
5.0
5.5
NA
4.0
3.0
                      'These are water column concentrations recommended to achieve the required intergravel dissolved oxygen con-
                    centrations shown in parentheses. The 3 mg/L differential is discussed in the criteria document. For species that have
                    early life stages exposed directly to the water column, the figures in parentheses apply.
                      -Includes all embryonic and larval stages and all juvenile forms to 30 days following hatching.
                      -'NA (not applicable!.
                      4For highly manipulatable discharges, further restrictions apply.
                      -'All minimum values should be considered as instantaneous concentrations to be achieved at all times.
                        Criteria for coldwater fish are intended to apply to waters containing a
                    population of one or more species in the  family Salmonidae or to waters
                    containing other coldwater or coolwater  fish deemed by the user to be
                    closer to salmonids in sensitivity than to most warmwater species. Al-
                    though the acute lethal limit for salmonids is at or below 3 mg/L, the
                    coldwater minimum has been established at 4 mg/L because a significant
                    proportion of the insect species common to salmonid habitats are less tol-
                    erant of acute exposures to low dissolved oxygen than are salmonids.
                    Some coolwater species may require more  protection than that afforded by
                    the other life-stage criteria  for warmwater fish, and protecting sensitive
                    coolwater species with the coldwater criteria may be desirable.
                        Many States have  more  stringent dissolved oxygen  standards for
                    cooler waters that contain either salmonids, nonsalmonid coolwater fish,
                    or the sensitive Centrarchidae, the smallmouth bass. The warmwater crite-
                    ria are necessary to protect early life stages of warmwater fish as sensitive
                    as channel catfish and to protect other life stages of fish as sensitive as
                    largemouth bass. Criteria for early life stages are intended to apply only
                    where and when these stages occur. These  criteria represent dissolved oxy-
                    gen concentrations that EPA believes provide a reasonable and adequate
                    degree of protection for freshwater aquatic life.
                        The criteria do not represent assured no-effect levels. However, be-
                    cause  the  criteria  represent  worst  case  conditions (i.e, for wasteload

                                                                                   111

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                    allocation and waste treatment plant design), conditions will be better than
                    the criteria nearly all of the time at most sites. In situations where criteria
                    conditions are just maintained for considerable periods, the proposed cri-
                    teria represent some risk of production impairment. This impairment
                    would depend on innumerable  other factors. If slight production impair-
                    ment  or a small  but  undefinable  risk  of  moderate  impairment is
                    unacceptable, then one should use the "no production impairment" values
                    given in the document as means and the "slight production impairment"
                    values as minimum. Table 2 presents these concentrations.

                       The criteria represent dissolved oxygen concentrations believed to pro-
                    tect the  more sensitive  populations  of  organisms against potentially
                    damaging production impairment. The dissolved oxygen concentrations
                    in the criteria are intended to be  protective at typically high, seasonal envi-
                    ronmental  temperatures  for the appropriate  taxonomic and  life-stage
                    classifications, temperatures that are often higher than those used in the
                    research from  which the criteria were generated, especially for other than
                    early life stages.

                       Where  natural  conditions alone create dissolved  oxygen concentra-
                    tions less than 110  percent of the applicable criteria means or minima or
                    both, the minimum acceptable concentration is 90 percent of the natural
                    concentration. These values are  similar to those presented graphically and
                    to those calculated from 1972 Water Quality Criteria. Absolutely no anthro-

                    Table 2.—Dissolved oxygen concentrations (MG/L) versus quantitative level of effect.

                    1. Salmonid Waters

                      a.  Embryo and Larval Stages
                         No Production Impairment      = 11* (8)
                         Slight Production  Impairment    =  9* (6)
                         Moderate Production Impairment  =  8* (5)
                         Severe Production Impairment   =  7* (4)
                         Limit to Avoid Acute Mortality  =  6* (3)

                    *Note: These are water column concentrations recommended to achieve the required
                    intergravel  dissolved oxygen concentrations shown in parentheses. The 3 mg/L dif-
                    ference is discussed in the criteria document.

                      b. Other Life Stages
                        No Production Impairment      =  8
                        Light Production Impairment     =  6
                        Moderate Production Impairment  =  5
                        Severe Production Impairment   =  4
                        Limit to Avoid Acute Mortality  =  3

                    2. Nonsalmonid Waters

                      a. Early Life Stages
                        No Production Impairment      =  6.5
                        Slight Production  Impairment    =  5.5
                        Moderate Production Impairment  =  5
                        Severe Production Impairment   =  4.5
                        Limit to Avoid Acute Mortality  =  4

                      b. Other Life Stages
                        No Production Impairment      =  6
                         Slight Production  Impairment    =  5
                        Moderate Production Impairment  =  4
                        Severe Production Impairment   =  3.5
                        Limit to Avoid Acute Mortality  =  3

                      3.  Invertebrates
                        No Production Impairment      =  8
                        Some Production  impairment    =  5
                        Acute Mortality Limit          =  4
112

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pogenic dissolved oxygen depression in the potentially lethal area below
the one-day minima should be allowed unless special care is taken to as-
certain the tolerance of resident species to low dissolved oxygen.
    If daily cycles of dissolved oxygen are essentially sinusoidal, a reason-
able daily average  is  calculated from the day's high and low dissolved
oxygen values. A time-weighted average may be required if the dissolved
oxygen cycles are decidedly nonsinusoidal. Determining the magnitude of
daily dissolved oxygen cycles requires at least two appropriately timed
measurements daily, and characterizing the shape of the cycle requires
several more appropriately spaced measurements.
    Once a series of daily mean dissolved oxygen concentrations are calcu-
lated, an average of these daily means can be  calculated (Table 3). For
embryonic, larval, and early life stages, the averaging period should not
exceed seven days.  This short time is needed to adequately protect these
often short-duration, most sensitive life stages. Other life stages can prob-
ably be  adequately protected  by 30-day averages. Regardless of the
averaging period, the average  should  be considered a moving average
rather than a calendar-week or calendar-month average.

Table 3.—Sample calculations for determining daily means and seven-day mean
dissolved oxygen concentrations (30-day averages are calculated in a similar fashion
using 30 days data).
DAY
1 	
2
3 	
4
5
6 	
7 	
1-day Minimun
7-day Mean Mi
7-day Mean
DISSOLVED OXYGEN fMG/L)
DAILY MAX. DAILY MIN.
9.0
10.0
11.0
12.0"
10.0
11.0
12.0"
\
nimum 	


7.0
7.0
8.0
8.0
8.0
9.0
10.0
57.0
7.0
8.1

DAILY MEAN
8.0
8.5
9.5"
9.5
9.0
10.0
10. 5C
65.0
9.3
  JAbove air saturation concentration (assumed to be 11.0 m«/L for this example).
  "(11.0 + 8.0)2.
  C(II.O +• 10.012.
    The criteria have been established on the basis that the maximum dis-
solved oxygen value actually used in calculating any daily mean should
not exceed the air saturation value. This consideration is based primarily
on analysis of studies of cycling dissolved oxygen and the growth of large-
mouth bass, which indicated that high dissolved oxygen levels (6 mg/L)
had no beneficial effect on growth.
    During periodic cycles of dissolved oxygen concentrations, minima
lower than acceptable constant exposure levels are tolerable so long as:

   1.   The average concentration attained meets or exceeds the criterion;

   2.   The average dissolved oxygen concentration is calculated as
       recommended in Table 3; and

   3.   The minima are not unduly stressful and clearly are not lethal.

    A daily minimum has been included to make  certain that no acute
mortality of sensitive species occurs as a result of lack of oxygen. Because
repeated exposure to dissolved oxygen concentrations at or near the acute
lethal threshold will be stressful and because stress can indirectly produce
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                   mortality or other adverse effects (e.g., through disease), the criteria are
                   designed to prevent significant episodes of continuous or regularly recur-
                   ring exposures to dissolved oxygen concentrations at or near the lethal
                   threshold. This protection has been achieved by setting the daily minimum
                   for early life stages at the subacute lethality threshold, by the use of a
                   seven-day averaging period for early life stages, by stipulating a seven-
                   day mean minimum value for other life stages, and by recommending
                   additional limits for manipulatable discharges.
                       The previous EPA criterion for dissolved oxygen published in "Quality
                   Criteria for Water" (1976) was a minimum of 5 mg/L (usually applied as a
                   7Q10), which is similar to the current criterion minimum except for other
                   life stages of warmwater fish that now allows a seven-day mean minimum
                   of 4 mg/L. The  new criteria are similar to those contained in the 1968
                   "Green Book" of the Federal Water Pollution Control Federation.

The Criteria and Monitoring and Design Conditions

                   The acceptable mean concentrations should be attained most of the time,
                   but some deviation below these values would probably not cause signifi-
                   cant harm. Deviations below the mean will probably be serially correlated
                   and hence apt to occur on consecutive days. The significance of deviations
                   below the mean  will depend on whether they occur continuously or in
                   daily cycles, the former being more adverse than the latter. Current knowl-
                   edge regarding such deviations is limited primarily to laboratory growth
                   experiments and by extrapolation to other activity-related phenomena.
                       Under conditions where large daily cycles of dissolved oxygen occur, it
                   is possible  to meet the criteria mean values and consistently violate the
                   mean minimum criteria. Under these conditions, the mean minimum crite-
                   ria will clearly be  the limiting regulation unless alternatives,  such as
                   nutrient control, can dampen the daily cycles.
                       The significance of conditions that fail to meet the recommended dis-
                   solved oxygen criteria depend largely upon five factors: (1) the duration of
                   the event; (2) the magnitude of the dissolved oxygen depression; (3) the fre-
                   quency of recurrence; (4) the proportional area of the site failing to meet the
                   criteria; and (5) the biological significance of the site where the event oc-
                   curs.
                       Evaluation of an event's significance must be largely case-and site-spe-
                   cific. Common sense would dictate  that the magnitude of the depression
                   would be the single most important factor in general, especially if the
                   acute value is violated. A logical extension of these considerations is that
                   the event must be considered in the context of the resolution level of the
                   monitoring or modeling effort. Evaluating the extent, duration, and mag-
                   nitude of an event must be  a  function of the spatial  and  temporal
                   frequency of the data. Thus, a single deviation below the criterion takes on
                   considerably less significance where continuous  monitoring occurs than
                   where sampling is comprised of once-a-week grab samples. This is so be-
                   cause, based  on continuous monitoring, the event is  provably small; but
                   with the much less frequent sampling, the event is not provably small and
                   can be considerably worse than indicated by the sample.
                       The frequency of recurrence is of considerable interest to those model-
                   ing dissolved oxygen concentrations because the return period, or period
                   between  recurrences, is a primary modeling consideration contingent
                   upon probabilities of receiving water volumes, waste loads, temperatures,
                   and so forth. It should be apparent that the return period cannot be iso-
                   lated from the other four factors discussed above. Ultimately, the question

 114

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                   of return period may be decided on a site-specific basis, taking into ac-
                   count the other factors (duration, magnitude, areal extent, and biological
                   significance) mentioned above. Future studies of temporal patterns of dis-
                   solved oxygen concentrations, both within and between years, must be
                   conducted to provide a better basis for selection of the appropriate return
                   period.
                       In conducting wasteload allocation and treatment plant design compu-
                   tations, the choice of temperature in the models  will  be important.
                   Probably the best option would be to use temperatures consistent with
                   those expected in the receiving water over the critical dissolved oxygen
                   period for the biota.
The Criteria and Manipulatable Discharges
                   If daily minimum DOs are perfectly serially correlated (i.e, if the annual
                   lowest daily minimum dissolved oxygen concentration is adjacent in time
                   to the next lower daily minimum dissolved oxygen concentration, and one
                   of these two minima is adjacent to the third lowest daily minimum dis-
                   solved oxygen concentration, and  so  on), then, to meet the seven-day
                   mean minimum criterion, more than three or four consecutive daily mini-
                   mum values below the acceptable seven-day mean minimum will not
                   likely occur. Unless the dissolved oxygen pattern is extremely erratic, it is
                   also unlikely that the lowest dissolved oxygen concentration will be appre-
                   ciably  below  the' acceptable seven-day mean  minimum, or that  daily
                   minimum values below the seven-day mean minimum will occur in more
                   than one or two weeks each year.
                       For some discharges, the distribution of dissolved oxygen concentra-
                   tions can be manipulated to varying degrees. Applying the daily minimum
                   to manipulatable discharges would allow repeated weekly cycles of mini-
                   mum  acutely  acceptable dissolved  oxygen  values,  a condition of
                   unacceptable stress, and possible adverse biological effect. For this reason,
                   the application of the one-day minimum criterion to manipulatable dis-
                   charges must limit either the frequency of occurrence of values below the
                   acceptable seven-day mean minimum or must impose further limits on the
                   extent of excursions below the seven-day mean minimum. For such con-
                   trolled discharges, the occurrence  of daily  minima below the acceptable
                   seven-day mean minimum should be limited to three weeks per year or
                   the acceptable one-day minimum should be increased to 4.5 mg/L for
                   coldwater fish and 3.5 mg/L for warm water fish. Such decisions could be
                   site-specific based upon the extent of control and serial correlation.
                    (51 F.R. 22978, June 24,1986)
                    See Appendix A for Aquatic Life Methodology.
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            DISSOLVED  SOLIDS  AND  SALINITY
CRITERIA
                  250 mg/L for chlorides and sulfates in domestic water supplies (welfare).
Introduction      Dissolved solids and total dissolved solids, terms generally associated
                  with freshwater systems, consist of inorganic salts, small amounts of or-
                  ganic matter, and  dissolved  materials. The equivalent terminology in
                  Standard Methods is "filtrable residue." Salinity, an oceanographic term, is
                  not precisely equivalent to the total dissolved salt content but is related.
                  For most purposes, the terms "total dissolved salt content" and "salinity"
                  are equivalent. The principal inorganic anions dissolved in water include
                  the carbonates, chlorides, sulfates, and nitrates (principally in ground wa-
                  ters);  the  principal cations  are  sodium, potassium,  calcium,  and
                  magnesium.
                  (Quality Criteria for Water, July 1976) PB-263943
                  See Appendix D for Methodology.
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                              ENDOSULFAN
                                  CAS# 115-29-7
CRITERIA

Aquatic Life
Human Health
The criterion to protect freshwater aquatic life as derived using the guide-
lines is 0.056 ng/L as a 24-hour average; the  concentration should not
exceed 0.22 ug/L at any time.
   The criterion to protect saltwater aquatic  life as derived using the
guidelines is 0.0087 ng/L as a 24-hour average; the concentration should
not exceed 0.034 ng/L at any time.

Human health criteria were recalculated using Integrated Risk Informa-
tion System  (IRIS) to reflect available data as of 12/92 (57 F.R. 60848).
Recalculate IRIS values for alpha-endosulfan, beta-endosulfan and endo-
sulfan sulfate are 0.93 ng/L  for ingestion of contaminated water and
organisms and 2.0 ng/L for ingestion of contaminated aquatic organisms
only.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60848, December 22,1992)
                   See Appendix B for Aquatic Life Methodology.
                   See Appendix C for Human Health Mehtodology.
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                                   *ENDRIN
                                   CAS# 72-20-8
CRITERIA

Aquatic Life
Human Health
The criterion to protect freshwater aquatic life exposed to endrin, as de-
rived using the guidelines, is 0.0023 ng/L as  a 24-hour average; the
concentration should not exceed 0.18 ng/L at any time.
   The criterion to protect saltwater aquatic life exposed to endrin, as de-
rived using the guidelines, is 0.0023 ng/L as  a 24-hour average; the
concentration should not exceed 0.037 ng/L at any time.

Human health criteria were recalculated using Integrated Risk Informa-
tion  System (IRIS) to reflect available data as of 12/92  (57 RR. 60848).
Recalculated IRIS values for both endrin and endrin aldehyde are 0.76
Hg/L for ingestion of contaminated water and organisms and 0.81 ng/L
for ingestion of contaminated aquatic organisms only.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60848, December 22,1992)
                   See Appendix B for Aquatic Life Methodology.
                   See Appendix C for Human Health Mehtodology.
                   'Indicates suspension, cancelation, or restriction by U.S. EPA Office of Pesticides and
                    Toxic Substances.
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                            ETHYLBENZENE
                                  CAS# 100-41-4
CRITERIA

Aquatic Life
Human Health
The available data for ethylbenzene indicate that acute toxicity to freshwa-
ter aquatic life occurs at concentrations as low as 32,000 ng/L and would
occur at lower concentrations among species that are more sensitive than
those tested. No definitive data are available concerning the chronic toxic-
ity of ethylbenzene to sensitive freshwater aquatic life.
   The available data for ethylbenzene indicate that acute toxicity to salt-
water aquatic life occurs at concentrations as low as 430 ng/L and would
occur at lower concentrations among species that are more sensitive than
those tested. No data are available concerning the chronic toxicity of ethyl-
benzene to sensitive saltwater aquatic life.

Human health  criteria were  recalculated using Integrated Risk Informa-
tion  System (IRIS) to reflect available data as of 12/92 (57 F.R. 60848).
Recalculated IRIS values for ethylbenzene are 3,100 ng/L for ingestion of
contaminated water and organisms and 29,000 ng/L for ingestion of con-
taminated aquatic organisms only.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60912, December 22,1992)
                   See Appendix C for Human Health Methodology.
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                           FLUORANTHENE
                                  CAS# 206-44-0
CRITERIA

Aquatic Life
Human Health
The available data for fluoranthene indicate that acute toxicity to freshwa-
ter aquatic life occurs at concentrations as low as 3,980 ng/L and would
occur at lower concentrations among species that are more sensitive than
those tested. No data  are available concerning the chronic toxicity of
fluoranthene to sensitive freshwater aquatic life.
   The available data for fluoranthene indicate that acute and chronic tox-
icity to saltwater aquatic life occur at concentrations as low as 40 and 16
Hg/L, respectively, and would occur at lower concentrations among spe-
cies that are more sensitive than those tested.

Human health criteria were recalculated using Integrated Risk Informa-
tion  System (IRIS) to reflect available data as of 12/92 (57 ER. 60848).
Recalculated IRIS values for fluoranthene are 300 ng/L for ingestion of
contaminated water and organisms and 370 ng/L for ingestion of contami-
nated organisms only.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60848, December 22,1992)
                   See Appendix C for Human Health Methodology.
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                    GASES, TOTAL  DISSOLVED
CRITERIA

Aquatic Life


Rationale
To protect freshwater and saltwater aquatic life, the total dissolved gas
concentrations in water should not exceed 110 percent of the saturation.
value for gases at the existing atmospheric and hydrostatic pressures.

Fish in water containing excessive dissolved gas pressure or tension are
killed when dissolving gases in their circulatory system come out of solu-
tion to form bubbles (emoli) that block the flow  of blood through the
capillary vessels. In aquatic organisms this is commonly referred to as "gas
bubble disease." External bubbles (emphysema) also appear in the fins, on
the opercula, in the skin, and in other body tissues. Aquatic invertebrates
are also affected by gas bubble disease but usually at supersaturation lev-
els higher than those lethal to fish.
    Percent saturation of water containing a given amount of gas varies
with the absolute temperature and the pressure. Because of the pressure
changes, percent saturation with a given amount of gas changes with the
water depth. Gas supersaturation decreases by 10 percent per meter of in-
crease in water depth  due to hydrostratic pressure; a gas that is  at 130
percent saturation at the surface would be at 100 percent saturation at 3
meters' depth. Compensation for altitude may be needed because a reduc-
tion in atmostpheric   pressure  changes the  water/gas equilibrium,
resulting in changes in solubility of dissolved gases.

   Total dissolved gas supersaturation can occur in several ways:

   1.   Excessive biological activity: dissolved oxygen PO)
       concentrations can reach supersaturation as a result of excessive
       algal photosynthesis. Algal blooms are often accompanied by
       increased water temperatures, which further contribute to
       supersaturation.

    2.  Water spillage from hydropower dams causes supersaturation.

    3.  Gas bubble disease may be  induced by discharges from
       power-generating and other thermal sources. Discharged water
       becomes supersaturated with gases.

    In recent years, gas bubble disease has been identified as a major prob-
lem affecting valuable  stocks of salmon and trout in the Columbia River
system. The disease is caused by high concentrations of dissolved  atmos-
pheric  gas which enters the  river's water  during  heavy spilling at
hydroelectric dams.

   Field and laboratory reports result in several conclusions:

   1.   When either juvenile or adult salmonids are confined to shallow
       water (1M), substantial mortality occurs at and above 115 percent
       total dissolved gas saturation.

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                      2.  When either juvenile or adult salmonids are free to sound and
                         obtain hydrostatic compensation either in the laboratory or in the
                         field, substantial mortality still occurs when saturation levels (of
                         total dissolved gases) exceed 120 percent saturation.

                      3.  Using survival estimates made in the Snake River from 1966 to
                         1975, it is concluded that juvenile fish losses ranging from 40 to 95
                         percent do occur. A major portion of this mortality can be
                         attributed to fish exposure to supersaturation by atmospheric
                         gases during years of high flow.

                      4.  Juvenile salmonids subjected to sublethal periods of exposure to
                         supersaturation can recover when returned to normally saturated
                         water, but adults do not recover and generally die from direct and
                         indirect effects of the exposure.

                      5.  Some species of salmon and trout can detect and avoid
                         supersaturated waters; others may not.

                      6.  Higher survival was observed during periods of intermittent
                         exposure than during continuous exposure.

                      7.  In general, in acute bioassays, salmon and trout were less tolerant
                         than the nonsalmonids.

                      Interested individuals should review the original document for associ-
                  ated references and reports. This document is available from the National
                  Technical Information Service (NTIS). See Appendix F for ordering infor-
                  mation.
                      No differences are  proposed in the  criteria for freshwater and marine
                  aquatic life, as available data indicate little difference in overall tolerance
                  between saltwater and freshwater species.
                   (Quality Criteria for Water, July 1976) PB-263943
                   See Appendix D for Methodology.
128

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                                  GUTHION
                                   CAS# 86-50-0
CRITERIA

Aquatic Life

Rationale
.01 ng/L for freshwater and saltwater aquatic life.

Four-day LC50 values for fish exposed to the organophosphate pesticide
range from 4 to 4,270 ug/L. Decreased spawning was documented in fat-
head minnows exposed to low levels during complete life-cycle exposures.
The estimated "safe" long-term concentration for this species is 0.3 ug/L to
0.5 jig/L.
   Organophosphate pesticides inhibit the enzyme acetylchlolinesterase
(AChE), which is essential to nerve impulse transport. Inhibition of 40 to
70 percent of fish brain AChE is usually fatal. Centrarchids are considered
one of the most sensitive fish to guthion.
   Four-day LC50 values for aquatic invertebrates range from 0.10 ug/L
to 22.0 ug/L, indicating an overall greater sensitivity than fish and a nar-
rower spectrum of tolerance across species.
   Results of toxicity studies with marine organisms indicate similar re-
sponses, with saltwater  invertebrates exhibiting LCSOs as low as 0.33
ug/L.
   A criterion level of 0.01 ug/L for guthion is based on the use of 0.1 as
an application factor, applied to the 96-hour LC50 of 0.1 ug/L (for the am-
phipod, Gammarus) and  a similar value of 0.3 ug/L, exhibited by  the
European shrimp.
                   (Quality Criteria for Water, July 1976) PB-263943
                   See Appendix D for Methodology.
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130

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                              HALOETHERS
CRITERIA
Aquatic Life      The available data for haloethers indicate that acute and chronic toxicity to
                   freshwater aquatic  life occurs at concentrations as low as 360 and 122
                   Hg/L, respectively, and would occur at lower concentrations among spe-
                   cies that are more sensitive than those tested.
                      No saltwater organisms have been tested with any haloether, and
                   therefore, no statement can be made concerning acute or chronic toxicity.

Human Health    Using the present guidelines, a satisfactory criterion cannot be derived at
                   this time because of insufficient available data for haloethers. See also
                   chloroalkyl ethers.
                   (45 F.R. 79318, November 28,1980)
                   See Appendix B for Aquatic Life Methodology.
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CRITERIA
                            HALOMETHANES
Aquatic Life      The available data for halomethanes indicate that acute toxicity to fresh-
                   water aquatic life occurs at concentrations as low as 11,000 ug/L and
                   would occur at lower concentrations among species that are more sensitive
                   than those tested. No data are available concerning the chronic toxicity of
                   halomethanes to sensitive freshwater aquatic life.
                      The available data for halomethanes indicate that acute and chronic
                   toxicity to saltwater aquatic life occurs at concentrations as low as  12,000
                   and 6,400 ng/L, respectively, and  would occur at lower concentrations
                   among species that are more sensitive than those tested. A decrease in al-
                   gal cell numbers occurs at concentrations as low as 11,500 ng/L.

Human Health    For the maximum protection of human health from the potential carcino-
                   genic effects of exposure through the ingestion of contaminated water and
                   aquatic organisms for bromoform, dichlorobromomethane, and methylene
                   chloride, the ambient water concentration should be zero. However, zero
                   levels may not be attainable at the present time. Therefore, the levels that
                   may result in incremental increase  of cancer risk over a lifetime are esti-
                   mated at 10'5,10"6, and 10'7.

Bromoform (Tribromomethane) 75-25-2
                   Human health criteria were recalculated using the Integrated Risk Infor-
                   mation System (IRIS) to reflect available data as of 12/92 (57 F.R. 60848).
                   Recalculated IRIS values  for bromoform are 4.3 ug/L for ingestion of con-
                   taminated  water  and  organisms and  360  ng/L  for ingestion  of
                   contaminated organisms only. IRIS values are based on a 10"6 risk level for
                   carcinogens.

Dichlorobromomethane 75-27-4
                   Human health criteria were recalculated using the IRIS to reflect available
                   data as of 12/92 (57 F.R. 60848). Recalculated IRIS values for dichlorobro-
                   momethane  are 0.27 ug/L for ingestion of contaminated water and
                   organisms and 22 ug/L for ingestion of contaminated organisms only. IRIS
                   values are based on a  10"6 risk level  for carcinogens.

Methylene Chloride 75-09-2
                   Human health criteria were recalculated using the IRIS to reflect available
                   data as of 12/92 (57 F.R. 60848). Recalculated IRIS values for methylene
                   chloride are 4.7 ug/L for ingestion  of contaminated water and organisms
                   and 1,600 ug/L for ingestion of contaminated organisms only. IRIS values
                   are based on a 10"6 risk level for carcinogens.

Methyl Chloride (Chloromethane) 74-87-3
                   Human  health criteria have been  withdrawn for this compound
                   (57 F.R. 60848, December 22,1992).  However, EPA published a document,
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                   "Ambient Water Quality Criteria for Halomethanes," which includes this
                   compound. This document may contain useful information on human
                   health and was originally noticed on December 22,1992.
Methyl Bromide (Bromomethane) 74-83-9
                   Human health criteria were recalculated using the IRIS to reflect available
                   data as of 12/92 (57 F.R. 60848). Recalculated IRIS values for methyl bro-
                   mide are 48 ng/L for ingestion of contaminated water and organisms and
                   4000 ng/L for ingestion of contaminated organisms only.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60848, December 22,1992)
                   See Appendix C for Human Health Methodology.
 134

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                                 HARDNESS
CRITERIA

Introduction
Water hardness is caused by polyvalent metallic ions dissolved in water. In
fresh water, these metallic ions are primarily calcium and magnesium, al-
though other metals such as iron, strontium, and manganese can also be
present in appreciable concentrations. Commonly, hardness is reported as
an equivalent concentration of calcium carbonate (CaCO3).
   The concept of hardness comes from water supply practices: it is meas-
ured by  soap  requirements  for adequate lather formation and as an
indicator of the rate of scale formation in hot water heaters and low pres-
sure boilers. A commonly used classification is given in Table 1.

Table 1.—Classification of water by hardness content.
MAXIMUM CONCENTRATION
MG/L AS CACOj
0- 75
75-150 	
150-300
300 and up 	

WATER DESCRIPTION
soft
moderately hard
hard
very hard

Rationale
   The principal natural source of hardness is limestone, which is dis-
solved by percolating rainwater made acid by carbon dioxide. Industrial
and industrially related sources of hardness include the inorganic chemical
industry and discharges from operating and abandoned mines.
   Hardness in fresh water frequently is distinguished in carbonate and
noncarbonate fractions: carbonate fractions  are chemically equivalent to
the bicarbonates present in water. Since bicarbonates generally are meas-
ured as alkalinity, the carbonate hardness is usually considered equal to
the alkalinity.

The determination of hardness in raw waters subsequently treated and
used for domestic water supplies is useful as a parameter to characterize
the total dissolved solids present and for calculating dosages where lime-
soda softening is practiced. Because hardness concentrations in water have
not been proven health related, the final level achieved is principally a
function of economics. Since hardness in water can be removed with treat-
ment by such processes as lime-soda softening and zeolite or ion exchange
systems, a criterion for raw waters used for public water supply is not
practical.
   The effects of hardness on freshwater fish and other aquatic life appear
to be related to  the ions causing the hardness rather than hardness. Both
the National  Technical Advisory Committee (NTAC) and The National
Academy of Sciences (NAS) panels have recommended against using the
term hardness but suggest including the concentrations of the  specific
ions. This procedure should avoid confusion in future studies but is not
                                                             135

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                   helpful in evaluating previous studies. For most existing data, it is difficult
                   to determine whether toxicity of various metal ions is reduced because of
                   the formation of metallic hydroxides and carbonates caused by the associ-
                   ated increases in alkalinity, or because of an antagonistic effect of one of
                   the principal cations contributing to hardness — e.g., calcium — or a com-
                   bination of both effects. One theory presented, without proof, that if cupric
                   ions were the toxic form of copper, whereas copper carbonate complexes
                   were relatively non-toxic, then the observed difference in toxicity of cop-
                   per between hard and  soft waters can be explained by the difference in
                   alkalinity rather than hardness. A review of the  literature on toxicity pre-
                   sented data showing that increasing calcium, in particular, reduced the
                   toxicity of other heavy  metals. Under usual conditions in fresh  water and
                   assuming that other bivalent metals behave similarly to copper,  we can as-
                   sume  that both effects occur simultaneously and explain the observed
                   reduction of toxicity of metals in waters containing carbonate hardness.
                   The amount of reduced toxicity related to hardness, as measured by a 40-
                   hour LC50 for rainbow trout, has been estimated to be about four times for
                   copper and zinc when the hardness was increased from 10 to 100 mg/L as
                   CaC03.
                      Limits on hardness for industrial uses are quite variable. Table 2 lists
                   maximum values accepted by various industries as a source of raw water.
                   Subsequent treatment generally can reduce harness to tolerable limits, al-
                   though costs of such treatment are an important factor in determining its
                   desirability for a particular water source.
                      Hardness is not a determination  of concern for irrigation water use.
                   The concentrations of- the cations  calcium and  magnesium,  which com-
                   prise hardness, are important in determining the exchangeable  sodium in
                   a given water. This particular calculation will be  discussed under total dis-
                   solved solids rather than hardness.


                   Table 2.—Maximum hardness levels accepted by industry as a raw water source.*
INDUSTRY
Electric utilities
Textile 	 	
Pulp and paper 	
Chemical
Petroleum 	
Primary metals

MAXIMUM CONCENTRATION
MG/L AS CACO,
5 000
120
475
1 000
900
1 000

                     'Requirements tor final use within a process may be essentially «ro. which requires treatment for concentration
                   reductions.
                   (Quality Criteria for Water, July 1976) PB-263943
                   See Appendix D for Methodology.
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                               HEPTACHLOR
                                   CAS# 76-44-8
CRITERIA

Aquatic Life
Human Health
The criterion to protect freshwater aquatic life for heptachlor and hepta-
chlor epoxide, as derived using the guidelines, is 0.0038 ng/L as a 24-hour
average, and the concentration should not exceed 0.52 ng/L at any time.
   The criterion to protect saltwater aquatic life for heptachlor and hepta-
chlor  expoxide, as derived using the guidelines, is 0.0036 ng/L as a
24-hour average. The concentration should not exceed 0.053 ng/L at any
time.

For the maximum protection of human health from potential carcinogenic
effects from exposure to heptachlor through ingestion of contaminated
water and contaminated aquatic organisms, the ambient water concentra-
tion should be zero,  based  on the nonthreshold assumption for this
chemical; however, zero level may not be attainable. Therefore, the levels
that may result in incremental increase of cancer risk over a lifetime are es-
timated at 10'5,10"6, and 10'7.
   Human health criteria were recalculated using Integrated Risk Infor-
mation System (IRIS) to reflect available data as of 12/92 (57 F.R. 60848).
Recaculated IRIS values for heptachlor is 0.00021 ng/L for ingestion of
contaminated water and organisms and for ingestion of contaminated
aquatic organisms only. IRIS values are based on a 10 risk level for car-
cinogens.
   Published human health criteria were recalculated using IRIS to reflect
available data as of 12/92 (57 F.R. 60848). Recalculated IRIS values for hep-
tachlor epoxide are 0.00010 ng/L for ingestion of contaminated water and
organisms and 0.00011 ng/L for ingestion of contaminated aquatic organ-
isms only. IRIS values are based on a 10"6 risk level for carcinogens.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60848, December 22,1992)
                   See Appendix B for Aquatic Life Methodology.
                   See Appendix C for Human Health Methodology.
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                   HEXACHLOROBENZENE
                             CAS# 118-74-1
CRITERIA
Aquatic Life     As of 8/88, a draft Ambient Water Quality Criteria (AWQC) document for
                hexachlorobenzene became available. Final rulemaking will eventually be
                promulgated, but as of this writing, aquatic life criteria for hexachloroben-
                zene has not been finalized.

Human Health   Refer to Chlorinated Benzenes.
                                                                   139

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                    HEXACHLOROBUTADIENE
                                   CAS# 86-68-3
CRITERIA

Aquatic Life
Human Health
The available data for hexachlorobutadiene indicate that acute and chronic
toxicity to freshwater aquatic life occur at concentrations as low as 90 and
9.3 fig/L, respectively, and would occur at lower concentrations among
species that are more sensitive than those tested.
   The available data for hexachlorobutadiene indicate that acute toxicity
to saltwater aquatic life  occurs at concentrations as low as 32 ng/L and
would occur at lower concentrations among species that are more sensitive
than those tested. No data  are available concerning the chronic toxicity of
hexachlorobutadiene to sensitive saltwater aquatic life.

For the maximum protection of human health from the potential carcino-
genic effects of exposure  to hexachlorobutadiene through ingestion of
contaminated water and contaminated aquatic organisms, the ambient
water concentrations should be zero, based on the nonthreshold assump-
tion  for  this chemical; however,  zero level  may  not be  attainable.
Therefore, the levels that may result in incremental increase of cancer risk
over a lifetime are estimated at 10"5,10"6, and 10"7.
   Human health criteria  were recalculated using Integrated Risk Infor-
mation System (IRIS) to  reflect avaialable data as of 12/92 (57 F.R. 60848).
Recalculated IRIS values for hexachlorobutadiene are 0.44 ng/L for inges-
tion  of contaminated water and organisms and 50 ng/L for ingestion of
contaminated aquatic organisms only. IRIS values are based on a 10  risk
level for carcinogens.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60848, December 22,1992)
                   See Appendix C for Human Health Methodology.
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142

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                 HEXACHLOROCYCLOHEXANE
                                  CAS# 58-89-9
CRITERIA       	

Aquatic Life

Gamma-hexachlorocyclohexane (Undone) 58-89-9
                   For  gamma-hexachlorocyclohexane  (lindane), the criterion to  protect
                   freshwater aquatic life as derived using the guidelines is 0.080 ng/L as a
                   24-hour average. The concentration  should not exceed 2.0 ng/L at any
                   time.
                      For saltwater aquatic life the concentration of lindane should not ex-
                   ceed 0.16  ng/L at any time. No data are available for lindane's chronic
                   toxicity to sensitive saltwater aquatic  life.
BHC 680-73-1
                   The available data for a mixture of isomers of benzene hexachloride (BHC)
                   indicate that acute toxicity to freshwater aquatic life occurs at concentra-
                   tions as low as 100 ug/L and would occur at lower concentrations among
                   species that are more sensitive than those tested. No data are available
                   concerning the chronic toxicity of a mixture of isomers of BHC to sensitive
                   freshwater aquatic life.
                      The available data for a mixture of isomers of BHC indicate that acute
                   toxicity to saltwater aquatic life  occurs at concentrations as  low as 0.34
                   ug/L and would occur at lower concentrations among species that are
                   more sensitive than those tested. No data are available concerning the
                   chronic toxicity of a mixture of isomers of BHC to sensitive saltwater
                   aquatic life.
Human Health
Alpha-hexachlorocydohexane 319-84-6
                   For the maximum protection of human health from the potential carcino-
                   genic  effects  of exposure  to  alpha-hexachlorocyclohexane  through
                   ingestion of contaminated water and contaminated aquatic organisms, the
                   ambient water concentrations should be zero, based on the nonthreshold
                   assumption for this chemical; however, zero level may not be attainable.
                   Therefore, the levels that may result in incremental increase of cancer risk
                   over the lifetime are estimated at 10'5, lO'6, and 10'7.
                      Human health criteria were recalculated using Integrated Risk Infor-
                   mation System (IRIS) to reflect available data as of 12/92 (57 F.R. 60848).
                   Recalculated IRIS values for hexachlorocyclohexane-alpha are 0.0039 for
                   ingestion of contaminated water and organisms and 0.013 for ingestion of
                   contaminated aquatic organisms only. IRIS values are based on a 10*6 risk
                   level for carcinogens.

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Beta-hexachlorocyclohexane 319-85-7
                   For the maximum protection of human health from the potential carcino-
                   genic effects of exposure to beta-hexachlorocyclohexane through ingestion
                   of contaminated water and contaminated aquatic organisms, the ambient
                   water concentrations should be zero, based on the nonthreshold assump-
                   tion for  this  chemical; however,  zero level  may not be  attainable.
                   Therefore, the levels that may result in incremental increase of cancer risk
                   over the lifetime are estimated at 10"5, 10"6, and 10'7. The corresponding
                   recommended criteria are  163 ng/L, 16.3 ng/L, and  1.63 ng/L, respec:
                   lively. If these estimates are made for consumption of aquatic organisms
                   only, excluding consumption of water, the levels are 547 ng/L, 54.7 ng/L,
                   and 5.47 ng/L, respectively.
                       Published human health criteria were recalculated using IRIS to reflect
                   available data as of 3/91. Recalculated IRIS values for hexachlorocyclohex-
                   ane-beta  are 0.014  ng/L  for ingestion of contaminated water  and
                   organisms and 0.046 ng/L for ingestion of contaminated aquatic organ-
                   isms only. IRIS values are based on a 10"6 risk level for carcinogens.
Gamma-hexachlorocydohexane (Lindane) 58-89-9
                   For the maximum protection of human health from the potential carcino-
                   genic effects due to exposure of gamma-hexachlorocyclohexane through
                   ingestion of contaminated water and contaminated aquatic organisms, the
                   ambient water concentrations should be zero, based on the nonthreshold
                   assumption for this chemical; however, zero level may not be attainable.
                   Therefore, the levels that may result in incremental increase of cancer risk
                   over a lifetime are estimated at 10"5,10"6, and 10"7. The corresponding rec-
                   ommended criteria are 186 ng/L, 18.6 ng/L, and 1.86 ng/L, respectively. If
                   these estimates are made for consumption of aquatic organisms only, ex-
                   cluding consumption of water, the levels are 625 ng/L, 62.5 ng/L, and 6.25
                   ng/L, respectively.
                       Published human health criteria were recalculated using IRIS to reflect
                   available data as of 3/91. Recalculated IRIS values for hexachlorocyclohex-
                   ane-gamma (Lindane) are 0.019 ng/L for ingestion of contaminated water
                   and organisms and 0.063 for ingestion of contaminated aquatic organisms
                   only. IRIS values are based on a 10"6 risk level for carcinogens.
Technical-hexachlorocyclohexane 319-86-8
                   Using the present guidelines, satisfactory criteria cannot now be derived
                   for delta and epsilon hexachlorocyclohexane because of insufficient data.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60848, December 22,1992)
                   See Appendix B for Aquatic Life Methodology.
                   See Appendix C for Human Health Methodology.
 144

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             HEXACHLOROCYCLOPENTADIENE
                                  CAS# 77-47-4
CRITERIA

Aquatic Life
Human Health
The available data for hexachlorocyclopentadiene indicate that acute and
chronic toxicity to freshwater aquatic life occurs at concentrations as low
as 7.0 and 5.2 ng/L, respectively, and would occur at lower concentrations
among species that are more sensitive than those tested.
   The available data for hexachlorocyclopentadiene indicate that acute
toxicity to saltwater aquatic life occurs at concentrations as low as 7.0 ng/L
and would occur at lower concentrations among species that are more sen-
sitive than those tested. No data are  available concerning the chronic
toxicity of hexachlorocyclopentadiene to sensitive saltwater aquatic life.

Human health criteria were recalculated using Integrated Risk Informa-
tion  System (IRIS) to reflect available  data as of 12/92 (57 F.R. 60848).
Recalculated IRIS values for hexachlorocyclopentadiene are 240.0 ng/L for
ingestion of contaminated water and organisms and 17,000. ng/L for in-
gestion of contaminated aquatic organisms only.
   Using available organoleptic data, the estimated level is 1 ng/L to con-
trol undesirable taste and odor quality of ambient water. Organoleptic data
have limitations as a basis for establishing water quality criteria but no
demonstrated relationship to potentially adverse effects on human health.
                  (45 F.R. 79318, November 28,1980) (57 F.R. 60848, December 22,1992)
                  See Appendix C for Human Health Methodology.
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146

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                                      IRON
                                   CAS# 7439-89-6
CRITERIA

Aquatic Life


Introduction
0.3 mg/L for domestic water supply (health).
1.0 mg/L for freshwater aquatic life.

Of the elements that make up the earth's crust, iron is the fourth most
abundant by weight. Common in many rocks, iron is an important compo-
nent of many soils  but especially  clay,  where  it is  usually  a  major
constituent. Iron may be present in varying quantities in water, depending
upon the area's geology and the waterway's other chemical components.
   Iron is an essential trace element required by both plants and animals.
In some waters, it may be a limiting factor for the growth of algae and
other plants, especially in some marl lakes where it is precipitated by the
highly alkaline conditions. Also, iron is a vital oxygen  transport mecha-
nism in the blood of all vertebrate and some invertebrate animals.
   The ferrous, or bivalent (Fe++), and the ferric, or bivalent (Fe"1"1"1), irons
are of primary concern in the aquatic environment, although other forms
of iron may occur in  organic and inorganic wastewater streams. The fer-
rous (Fe++) form can persist in waters void of  dissolved oxygen and
originates usually from groundwaters or mines that have been pumped or
drained. For practical purposes, the ferric (Fe+++) form is insoluble. Iron
can exist in  natural organometallic or humic compounds and  colloidal
forms. Black or brown swamp waters can contain iron  concentrations of
several mg/L in the presence or absence of dissolved oxygen, but this form
of iron has little effect on aquatic life.
   Soluble ferrous iron occurs in the deep waters of stratified lakes with
anaerobic hypolimnia. During the autumnal or vernal overturns and with
aeration of these lakes, it is oxidized rapidly to the ferric ion that precipi-
tates to the  bottom sediments as a  hydroxide, Fe(OH)3, or with other
anions. If hydrogen sulfide (H2S) is present in anaerobic bottom waters or
muds, ferrous sulfide (FeS) may be formed. Ferrous sulfide is a black com-
pound and produces black mineral muds.
   Prime iron pollution  sources are industrial wastes, mine drainage wa-
ters, and iron-bearing groundwaters.  In the presence of dissolved oxygen,
iron in water from mine drainage is precipitated as a hydroxide, Fe(OH)3.
These  yellowish or ochre precipitates  produce "yellow boy"  deposits
found in many streams draining coal  mining regions of Appalachia. Occa-
sionally, ferric oxide (Fe2O3) is precipitated, forming red waters. Both of
these precipitates form as gels or floes that may be detrimental  to fishes
and other aquatic life when suspended in water. These precipitates can set-
tle to  form flocculent  materials  that  cover  stream  bottoms, thereby
destroying bottom-dwelling invertebrates, plants, or incubating fish eggs.
With time these floes can consolidate to form cement-like materials, thus
consolidating bottom gravels into  pavement-like areas unsuitable  as
spawning sites for nest-building fishes. This is particularly detrimental to

                                                             147

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                    trout and salmon populations whose eggs are protected in the interstices
                    of gravel and incubated with oxygen-bearing waters passing through the
                    gravel.

Rational           Iron is an objectional constituent in water supplies for both domestic and
                    industrial use. Iron appreciably affects the taste of beverages and can stain
                    laundered clothes and plumping fixtures. A study by the Public Health
                    Service (see original document) indicates that the taste of iron may be de-
                    tected readily at 1.8 mg/L in spring water and at 3.4 mg/L in distilled
                    water.
                       The daily nutritional requirement for iron is 1 to 2 mg, but intake of
                    larger quantities is required as a result of poor absorption. Diets contain 7
                    to 35 mg per day and average 16 mg. The iron criterion in water to prevent
                    objectionable tastes or laundry staining (0.3 mg/L) constitutes only a small
                    fraction of the iron normally consumed and is of aesthetic rather than toxi-
                    cological significance.
                       Studies obtain 96-hour LC50  values of 0.32 mg/L iron for mayflies,
                    stoneflies, and caddisflies; all are important fish food organisms. Other
                    studies found  iron toxic to  carp (Cyrinus  carpio) at concentrations of
                    0.9 mg/L when the pH of the water was 5.5. Pike (Esox lucius) and trout
                    (species unknown) died at iron concentrations of 1 to 2 mg/L. In an iron
                    polluted Colorado stream, neither trout nor other fish were found until the
                    waters were diluted or the iron had precipitated to effect a concentration of
                    less than 1.0 mg/L, even though other water quality constituents were
                    suitable for the presence of trout.
                       Ferric hydroxide floes have been observed to coat the gills of white
                    perch (Morone  americanus), minnows, and silversides (Menidia sp).  The
                    smothering effects of settled  iron precipitates  may be particularly detri-
                    mental to  fish eggs and bottom-dwelling fish food organisms.  Iron
                    deposits in the Brule River, Michigan and Wisconsin, were found to have a
                    residual long-term effect on fish food organisms even after the pumping of
                    iron-bearing waters from deep shaft iron mines had ceased. Settling iron
                    floes have also been reported to trap and carry diatoms downward in wa-
                    ters.
                       In 69 of 75 study sites with good fish fauna, the iron concentrations
                    were less than 10.0 mg/L. The European Inland Fisheries Commission rec-
                    ommended that iron concentrations not exceed 1.0 mg/L in waters to be
                    managed for aquatic life.
                       Based principally on field observations, a criterion of 1 mg/L iron for
                    freshwater aquatic life is believed to be adequately protective. As noted,
                    data obtained under laboratory conditions suggest a greater toxicity for
                    iron than that obtained in natural ecosystems. Ambient natural waters will
                    vary according to alkalinity, pH, hardness, temperature, and the presence
                    of ligands, which change the valence state and solubility and therefore the
                    toxicity of the metal.
                       The  effects of iron  on marine life have not been investigated ade-
                    quately  to  determine a water  quality  criterion. Dissolved iron readily
                    precipitates in  alkaline  seawaters. Fears have  been expressed that these
                    settled iron floes may have adverse effects on important benthic commer-
                    cial mussels and other shellfish resources.
                       Iron has not been reported to have a direct effect on the recreational
                    uses of water, other than its effect on aquatic life. Suspended iron precipi-
                    tates may interfere with swimming and be aesthetically objectionable with
                    water deposits as yellow ochre or  reddish iron oxides.

 148

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   Iron at exceedingly high concentrations has been reported to be toxic
to livestock and interfere with the metabolism of phosphorus. Dietary sup-
plements  of phosphorus  can be  used  to  overcome this metabolic
deficiency. In aerated soils, iron in irrigation waters is not toxic. Precipi-
tated iron may be complex phosphorus and molybdenum, making them
less available as plant nutrients. In alkaline soils, iron may be so insoluble
as to be deficient as a trace element and result in chlorosis, an objectionable
plant nutrient deficiency disease. A reported reduction in the quality of to-
bacco was due to precipitate iron oxides on the leaves when the crop was
spray irrigated with water containing 5 mg/L of soluble iron.
   For some industries, iron concentrations in process waters lower than
that required for public water supplies are required or desirable. Examples
include high pressure boiler feed waters; scouring, bleaching, and dyeing
of textiles; certain types of paper production; some chemicals; some food
processing; and leather finishing industries.
(Quality Criteria for Water, July 1976) PB-263943
See Appendix D for Methodology.
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                              ISOPHORONE
                                   CAS# 78-59-1
CRITERIA

Aquatic Life
Human Health
The available data for isophorone indicate that acute toxicity to freshwater
aquatic life occurs at concentrations as low as 117,000 ng/L and would oc-
cur at lower concentrations among species that are more sensitive than
those tested. No data are available concerning the chronic toxicity of
isophorone to sensitive freshwater aquatic life.
   The available data for isophorone indicate that acute toxicity to saltwa-
ter aquatic life occurs at concentrations as low as 12,900 ng/L and would
occur at lower concentrations among species that are more sensitive than
those tested. No data are available concerning the chronic toxicity of
isophorone to sensitive saltwater aquatic life.

Human  health criteria were recalculated using Integrated Risk Informa-
tion  System (IRIS) to reflect available data as of 12/92  (57 F.R. 60848).
Recalculated~IRIS values for isophorone are 8.4 ng/L for ingestion of con-
taminated water and organisms and  600  for ingestion of contaminated
aquatic organisms only.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60848, December 22,1992)
                   See Appendix C for Human Health Methodology.
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CRITERIA
                                      LEAD
                                   CAS# 7439-92-1
Aquatic Life
Summary
                   Saltwater—   1-hour average of 220 ng/L
                                 4-day average of 8.5 ng/L
                   Freshwater criteria are hardness dependent. See text.

                   The acute toxicity of lead to several species of freshwater animals has been
                   shown to decrease as the hardness of water increases. At a hardness of 50
                   mg/L, the acute sensitivities of 10 species range from 142.5 ng/L for an
                   amphipod to 235,900 ng/L for a midge. Data on the chronic effects of lead
                   on freshwater animals are available for two fish and two invertebrate spe-
                   cies. The chronic toxicity of lead also decreases as hardness increases, and
                   the lowest and highest available chronic values (12.26 and 128.1 |ig/L) are
                   both for a  cladoceran,  but in  soft and hard water,  respectively. Acute-
                   chronic ratios  are available for three species and range from 18 to 62.
                   Freshwater algae are affected by concentrations of lead above 500 ug/L,
                   based on data for four  species. Bioconcentration factors are available for
                   four invertebrate and two fish species and range from 42 to 1,700.
                      Acute values are available for 13 saltwater animal species and range
                   from 315 ng/L for the mummichog to 27,000 ug/L for the soft shell clam. A
                   chronic toxicity test was conducted with a mysid; unacceptable  effects
                   were observed at 37 ug/L but not at 17 tig/L; the acute-chronic ratio for
                   this  species is 124.8. A species of macroalgae was affected at 20 fig/L.
                   Available bioconcentration factors range from 17.5 to 2,570.

National Criteria The  procedures described in the "Guidelines for Deriving Numerical Na-
                   tional Water Quality Criteria for the Protection of Aquatic Organisms and
                   Their Uses" indicate that, except possibly where a locally important spe-
                   cies  is very sensitive, freshwater aquatic organisms and their uses should
                   not  be affected unacceptably if the four-day average  concentration (in
                   »g/L) of lead does not exceed the numerical value given by
                                          _(1.273(1 n(hardness)]-4.705)
                                          6
                   more than  once every  three years on the average, and if  the one-hour
                   average concentration  (in ng/L) does  not  exceed the numerical value
                   given by
                                            (1.273fln(hardness)]-1.460)

                   more than  once every three  years on the average.  For example,  at
                   hardnesses of 50, 100,  and 200 mg/L  as CaCOa, the  four-day average
                   concentrations of lead  are 1.3, 3.2,  and 7.7 ng/L, respectively, and the
                   one-hour average concentrations are  34, 82, and 200 ug/L.
                       The procedures described in the guidelines indicate that, except possi-
                   bly where a locally important species is very sensitive, saltwater aquatic
                   organisms and their uses should not be affected unacceptably if the four-

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                   day average concentration of lead does not exceed 8.5* ng/L more than
                   once every three years on the average and if the one-hour average concen-
                   tration does not exceed 220* ng/L more than once every three years on the
                   average.
                      The recommended exceedence frequency of three years is the Agency's
                   best scientific judgment of the average time needed for an unstressed sys-
                   tem to recover from a pollution event in which lead exposure exceeds the
                   criterion. A stressed system — for example one, in which several outfalls
                   occur in a limited area — would be expected to require more recovery
                   time. The resilience of ecosystems and their ability to recover differ greatly,
                   however, and site-specific criteria may be established if adequate justifica-
                   tion is provided.
                      The use of criteria in designing waste treatment facilities requires the
                   selecting of an appropriate wasteload allocation model. Dynamic models
                   are preferred for applying these criteria. Limited data or other factors may
                   make their use impractical, in which case one should rely on a steady-state
                   model. The Agency recommends the interim use of 1Q5 or 1Q1O for Crite-
                   rion Maximum  Concentration design flow, and  7Q5 or  7Q1O for the
                   Criterion Continuous Concentration design flow in steady-state models
                   for unstressed and stressed systems, respectively. These matters are dis-
                   cussed in more  detail in EPA's "Technical Support Document for  Water
                   Quality-Based Toxics Control."

Human Hoalth    Human health criteria have been  withdrawn  for this compound (see
                   57 F.R. 60885, December 22,1992). Although the  human health criteria are
                   withdrawn, EPA published a document for this compound  that may con-
                   tain useful human health  information. This document was  originally
                   noticed in 45 F.R. 79331, November 28,1980.
                   (45 F.R. 79318 November 28,1980) (50 F.R. 30784, July 29,1985)
                   See Appendix A for Aquatic Life Methodology.


                   * Saltwater lead concentrations are based on a recalculation. See 57 F.R. 60882,
                   December 22,1992, Comment #45.
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                                 MALATHION
                                   CAS# 121-75-5
CRITERIA

Aquatic Life

Rationale
0.1 ug/L for freshwater and saltwater aquatic life.

Salmonids and centrarachids appear to be the most sensitive freshwater
fish to malathion. Documented 96-hour  LCSOs ranged from 120 to 265
Hg/L for four different salmonid species and 101 to 285 ug/L for three spe-
cies  of  centrarchids.  Reported  96-hour  LCSOs  for rainbow  trout
(Onchorhynchus mykiss), largemouth bass  (Micropterus salmoides), and chi-
nook salmon, (Onchorhynchus  tshawytcha)  were  86, 50,  and 28  ng/L,
respectively.
   Freshwater  invertebrates  are  generally  even  more  sensitive  to
malathion than fish. Reported 96-hour LCSOs  for amphipod Gammarus
lacustris and G. fasciutus were 1.0 and 0.76 ug/L, respectively. The 48-hour
LCSOs for the cladocerans Simocephalus serrulatus and Daphnia pulex ranged
from 1.8 to 3.5 ug/L, while the 24-hour LCSOs for two midge larvae species
averaged just over two M£/L in  tests with malathion.
   In flow-through exposures  to malathion with saltwater fish  (Lagodon
rhombides), 575 ug/L result in a 50 percent mortality rate in 3.5 hours and
caused about 75 percent brain acetylcholinesterase (AChE) inhibition.
Similar mortality and AChE inhibition is documented with other saltwater
fish as well. Static 96-hour tests  for saltwater teleosts exposed to malathion
indicates a broad spectrum of species sensitivities, with LC50 values rang-
ing  from 27 to  3,250  ug/L for several different species.  For the
commercially and economically important striped bass, Morone saxatilis, a
flow-through 96-hour LC50 of 14 ng/L is documented.
   Saltwater invertebrates are comparably sensitive  to the less-resistant
fish species with 96-hour LCSOs ranging from 33 n-g/L for sand shrimp
(Crangon septemspinosa) to 83 ug/L for the hermit crab (Pagurus longicor-
pus).
   Malathion enters the aquatic environment primarily as a result of its
application as an insecticide. Because it degrades quite rapidly in most wa-
ters, depending on pH, its occurrence is  sporadic rather than continous.
Because malathion's toxicity is  exerted through inhibition of the enzyme
AChE and because such inhibition may be additive with repeated expo-
sures and may be caused by any of the  organophosphorus  insecticides,
inhibition of AChE by more than 35 percent may be expected to result in
damage to aquatic organisms.
   An application factor of 0.1 is applied to the 96-hour LC50 data for
Gammarus lacustris, G. fasciatus, and Daphnia, which are all approximately
1.0 ug/L, yielding a criterion of O.lug/L.
                    (Quality Criteria for Water, July 1976) PB-263943
                    See Appendix D for Methodology.
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                               MANGANESE
                                  CAS# 7439-96-5
CRITERIA
Introduction
Rationale
50 ng/L for domestic water supply (health).
100 ng/L for protection of consumers of saltwater molluscs.

Manganese does not occur naturally as a metal but is found in various
salts and minerals that are frequently in association with iron compounds.
The principal manganese-containing substances are manganese dioxide
(MnO^, pyrolusite, manganese carbonate (rhodocrosite), and manganese
silicate (rhodonite).
   The oxides are the only important minerals mined. Manganese is not
mined in the United States, except when contained in iron ores that are de-
liberately used to form ferro-manganese alloys.
   The primary uses of manganese are in metal alloys, dry cell batteries,
micro-nutrient fertilizer additives, organic compounds used in paint dri-
ers, and as chemical reagents. Permanganates are very strong oxidizing
agents of organic materials.
   Manganese is a vital micro-nutrient for both plants and animals. When
manganese is not present in sufficient quantities, plants exhibit chlorosis (a
yellowing of the leaves) or failure of proper leaf development. Inadequate
quantities of manganese in domestic animal food results in reduced repro-
ductive capabilities and deformed or poorly maturing young. Livestock
feeds usually have sufficient manganese, but beef cattle on a high corn diet
may require a supplement.

Although inhaled manganese dusts have been reported to be toxic to hu-
mans, manganese normally is ingested as a trace nutrient in food. The
average human intake is approximately 10 mg per day. Very large doses of
ingested manganese can cause some disease and liver damage, but these
are not known to occur in the United States. Only a few manganese toxic-
ity problems  have  been found throughout the world, and these have
occurred under unique circimstances (i.e., a well in Japan near a deposit of
buried batteries).
   It  is possible to  partially sequester manganese with special treatment,
but manganese is not removed in the conventional treatment of domestic
waters. Consumer complaints arise when manganese exceeds a concentra-
tion of 150 ug/L in water supplies.  These complaints are  concerned
primarily with the brownish staining of laundry and objectionable tastes
in beverages. The presence of low concentrations of iron may intensify the
adverse effects of manganese. Manganese at concentrations of about 10 to
20 ng/L is acceptable to most consumers. A criterion for domestic water
supplies of 50 ng/L should minimize the objectionable qualities.
   Ions of manganese are found rarely at concentrations above 1 mg/L in
freshwater. The reported tolerance values range from 1.5 mg/L to over
1,000  mg/L. Thus, manganese is not considered to be a problem in fresh

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                 waters. Permanganates have been reported to kill fish in 8 to 18 hours at
                 concentrations of 2.2 to 4.1 mg/L. Permanganates are not persistent be-
                 cause they rapidly oxidize organic materials and are thereby reduced and
                 rendered nontoxic.
                     Few data are available on the toxicity of manganese to marine organ-
                 isms. The ambient  concentration of manganese  is about 2 ng/L. The
                 material is rapidly assimulated and bioconcentrated into nodules that are
                 deposited on the sea floor. The major problem with manganese may be
                 concentration in the edible portions of mollusks, as bioaccumulation fac-
                 tors as high as 12,000 have been reported. In order to protect against a
                 possible health hazard to humans by manganese accumulation in shellfish,
                 a criterion of 100 ug/L is recommended for marine water.
                     Manganese is not known to be a problem in water consumed by live-
                 stock.  At concentrations of slighly less than 1 mg/L to a few milligrams
                 per liter, manganese may be toxic to plants from irrigation water applied
                 to soils with pH values lower than 6.0. The problem may be rectified by
                 liming soils to increase the pH. Problems may develop with long-term (20-
                 year) continuous irrigation on other soils with water containing about 10
                 mg/L of manganese. But as stated previously, manganese rarely is found
                 in surface waters at concentrations greater than 1 mg/L. Thus, no specific
                 criterion for manganese in agricultural waters is proposed. In select areas
                 and where acidophilic crops are cultivated and irrigated, a criterion of 200
                 Ug/L is suggested for consideration.
                     Most indrustrial users of water can operate successfully where the cri-
                 terion proposed for public water supplies is observed. However, a more
                 restrictive criterion may be needed to protect or ensure product quality.
                 (Quality Criteria for Water, July 1976) PB-263943
                 See Appendix D for Methodology.
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                                 *MERCURY
                                   CAS# 7439-97-6
CRITERIA
AQUATIC LIFE
SUMMARY
                    Not to exceed 2.4 ng/L in fresh water or 2.1 ug/L in salt water.
                    0.012 and 0.025 ng/L for freshwater and saltwater aquatic life, respectively.
                   Data are available on the acute toxicity of mercury (II) to 28 genera of
                   freshwater animals. Acute values for invertebrate species range from 2.2
                   Hg/L for Daphnia pulex to 2,000 ng/L for three insects. Acute values for
                   fishes range from 30 ng/L for the guppy to 1,000 jig/L for the Mozambique
                   tilapia. Few data are available for various organomercury compounds and
                   mercurous nitrate, and they all appear to be 4 to 31 times more acutely
                   toxic than mercury (II).
                       Available chronic data indicate that methylmercury is the most chroni-
                   cally toxic of the tested mercury compounds. Tests on methylmercury with
                   Daphnia magna and brook trout (Salvelinus fontinalis) produced chronic val-
                   ues less than 0.07 ng/L. For mercury (II) the chronic value obtained with
                   D. magna was about 1.1 ng/L and the acute-chronic ratio was 4.5. In both a
                   life-cycle test and an early life-stage test on mercuric chloride with the fat-
                   head minnow  (Pinnephales promelas), the  chronic value was  less than 0.26
                   Hg/L, and the acute-chronic ratio was over 600.
                       Freshwater plants show a wide range of sensitivities to mercury, but
                   the most sensitive appear to be less affected than the most sensitive fresh-
                   water animals to both mercury (II) and methylmercury. A bioconcentration
                   factor of 4,994 is available for mercury (II), but the bioconcentration factors
                   for methylmercury range from 4,000 to 85,000.
                    •   Data on the acute toxicity of mercuric chloride are available for 29 gen-
                   era of  saltwater  animals,  including annelids,  molluscs, crustaceans,
                   echinoderms, and fishes. Acute values range from 3.5 ng/L for a mysid to
                   1,678 ng/L for winter flounder (Pseudo pleuroneotes americanus). Fishes tend
                   to be more resistant, and molluscs and crustaceans tend to be more sensi-
                   tive to the acute toxic effects of mercury (II). Results of a life-cycle test with
                   the mysid show that mercury (II) at  a concentration of 1.6 ug/L signifi-
                   cantly  affected  time of first spawn and productivity;  the  resulting
                   acute-chronic ratio was 3.1.
                       Concentrations of mercury that affected growth and photosynthetic
                   activity of one saltwater diatom and six species of brown algae range from
                   10 to 160 ng/L. Bioconcentration factors of 10,000 and 40,000  have been ob-
                   tained for mercuric chloride and methylmercury with an oyster.

National Criteria  Derivation of a water quality criterion for mercury is more  complex than
                   for most metals because of methylation of mercury in sediments, fish, and
                   their food chain.  Apparently, almost all mercury  currently being dis-

                    *Indicates suspension, cancelation, or restriction by U.S. EPA Office of Pesticides and
                    Toxic Substances.
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                 charged is mercury (II). Thus mercury (II) should be the only important
                 possible cause of acute toxicity, and the Criterion Maximum Concentra-
                 tions can be based on its acute values.
                     The best available data on long-term exposure of fish to mercury (II)
                 indicates that concentrations above 0.23 ng/L statistically affected fathead
                 minnows  significantly, causing the concentration of total mercury in the
                 whole body to exceed 1.0 mg/kg. Although it is not known what percent
                 of the mercury in the fish was methylmercury, it is also  not known
                 whether uptake from food would increase the concentration in natural
                 situations. Species  such as rainbow  trout (Oncorhynchus mykiss), coho
                 salmon (Oncorhynchus kisutch), and especially  the bluegill (Lqjomis  macro-
                 chirus) might suffer  chronic  effects  and  accumulate high  residues of
                 mercury as did the fathead minnow.
                     With regard to long-term exposure to methylmercury, scientists found
                 that brook trout can exceed the FDA action level without suffering statisti-
                 cally significant adverse effects on survival, growth, or reproduction. Thus
                 for methylmercury, the Final Residue Value would be substantially lower
                 than the Final Chronic Value.
                     Basing a freshwater criterion on the Final Residue Value of 0.012 ng/L
                 derived from the bioconcentration factor of 81,700 for methylmercury with
                 the  fathead minnow essentially assumes that all discharged mercury is
                 methylmercury. On the other  hand, in field situations uptake from food
                 might add to the uptake from water. Similar considerations apply to the
                 derivation of the saltwater criterion of 0.025 ng/L using the BCF of 40,000
                 obtained  for methylmercury with the eastern oyster. Because the Final
                 Residue Values for methylmercury  are  substantially below the  Final
                 Chronic Values for mercury (II),  of lesser importance is that many  fishes,
                 including  the  rainbow trout,  coho salmon, bluegill,  and haddock
                 (Melanogrammus aeglefinus), might not be  adequately protected by the
                 freshwater and saltwater Final Chronic Values  for mercury (II).
                     In contrast to the complexities of deriving numerical criteria for mer-
                 cury,  monitoring for  unacceptable  environmental effects  should be
                 relatively straightforward. The most sensitive adverse effect will probably
                 be to exceed the FDA action level. Therefore, existing discharges should be
                 acceptable if the concentration of methylmercury in the edible portion of
                 exposed consumed species does not exceed the FDA action level.
                     The procedures described  in the "Guidelines for Deriving Numerical
                 National Water Quality Criteria  for the Protection of Aquatic Organisms
                 and Their Uses" indicate that, except  possibly where a locally important
                 species is very  sensitive, freshwater  aquatic organisms and their uses
                 should not be affected unacceptably if the four-day average concentration
                 of mercury does not exceed 0.012 ng/L more than once every three years
                 on the average and if the one-hour average concentration does not exceed
                 2.4 ng/L more than once every three years on  the average. If the four-day
                 average concentration exceeds 0.012 ng/L  more than once in  a three-year
                 period, the edible portion of consumed species should be analyzed to de-
                 termine whether the concentration of methylmercury exceeds the FDA
                 action level.
                     The procedures described in the guidelines indicate that, except possi-
                 bly where a localy important  species  is very  sensitive, saltwater aquatic
                 organisms and their uses should not be affected unacceptably if the four-
                  day average concentration of mercury does not exceed 0.025 (ig/L more
                  than once every three years on the average and if the one-hour average
                  concentration does not exceed 2.1 ug/L more than once every three years

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                   on the average. If the four-day average concentration exceeds 0.025
                   more than once in a three-year period, the edible protion of consumed spe-
                   cies  should be analyzed  to  determine whether  the  concentration of
                   mathylmercury exceeds the FDA action level.
                      The recommended exceedence frequency of three years is the Agency's
                   best  scientific judgment of the average time needed for an unstressed sys-
                   tem  to recover from a pollution event  in which  exposure to mercury
                   exceeds the criterion. A stressed system, for example — one in which sev-
                   eral outfalls occur in a limited area — would be expected to require more
                   time for recovery.  The resilience of ecosystems and their ability to recover
                   differ greatly, however,  and site-specific criteria can be established if ade-
                   quate justification is provided.
                      The use of criteria in designing waste treatment facilities requires the
                   selection of an appropriate wasteload allocation model. Dynamic models
                   are preferred for the application of these criteria. Limited data or other fac-
                   tors  may make their use impractical, in which case  one should rely on a
                   steady-state model.  The Agency recommends  the interim use of 1Q5 or
                   1Q1O for Criterion Maximum Concentration design flow and 7Q5 or 7Q1O
                   for the Criterion  Continuous  Concentration design flow in steady-state
                   models for unstressed and stressed systems, respectively. These matters
                   are discussed in more detail in  EPA's "Technical Support Document for
                   Water Quality-Based Toxics Control."

Human Health
Criteria           The ambient water criterion is 144 ng/L for the protection of human health
                   from the toxic properties of mercury ingested through water and contami-
                   nated aquatic organisms.
                      For the protection of human health from the toxic properties of mer-
                   cury ingested through contaminated aquatic organisms alone, the ambient
                   water criterion is 146 ng/L.  These values include the  consumption of
                   freshwater, estuarine, and saltwater species.
                   (45 F.R. 79318 November 28,1980) (50 F.R. 30784, July 29,1985)
                   See Appendix A for Aquatic Life Methodology.
                   See Appendix C for Human Health Mehtodology.
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                           METHOXYCHLOR
                                   CAS# 72-435
CRITERIA
Rationale
100 ng/L for domestic water supply (health).
0.03 ng/L for freshwater and saltwater aquatic life.

Where adequate human data are available for corraboration of the animal
results, the total "safe" drinking intake level is assumed to be 1/100 of the
"no effect" or "minimal effect" level reported for the most sensitive animal
tested — in this case, humans.
    Applying the available data and assuming that 20 percent of the toal
intake of methoxychlor is from drinking water and that the average person
weighs 70 kg and consumes two liters of water per day, the formual for cal-
culating a criterion is 2.0 mg/kg x 0.2 x 70 kg x 1/100 x 1/2 = 0.14 ug/L. A
criterion level for domestic water supply of 100 ng/L is recommended.
    In tests  with aquatic organisms exposed  to methoxychlor,  reduced
hatchability  of fathead  minnow (Pimephales promelas) embryos  at 0.125
Hg/L and lack of spawning at 2.0 ng/L was observed. Yellow perch (Perca
flavescens) exposed to 0.6 ng/L methoxychlor for 8 months exhibited re-
duced growth. The four-day LCSOs for the  fathead minnow, the yellow
perch, and economically important striped bass (Morone saxatilis) were 7.5,
22, and 3.3 ng/L,  respectively.
    The four-day  LCSOs for aquatic invertebrates were as low as 0.61 ng/L
for the scud  (Gammarus pseudolimnaeus) and ranged from 1.6 to 7 ng/L for
three insect larvae and a crayfish. In 28-day tests, reduction in emergence
or  pupation of aquatic  insects was observed at 0.25  to 0.5 ng/L of
methoxychlor.
    The data indicate that 0.1 ng/L methoxychlor would be just below the
chronic effect level for the fathead minnow and V$ the acute toxicity level
in crayfish. Thus, a criterion level of 0.03 ng/L is recommended. The 96-
hour LC50 for the marine pink shrimp (Penaeus duorarum)  exposed to
methoxychlor is 3.5 ng/L. The 30-day LC50 was 1.3 [ig/L.  Applying an ap-
plication factor of 0.01 with the pink shrimp acute toxicity of 3.5 ng/'L, the
recommended criterion for a saltwater environment is also 0.03 ng/L.
                   (Quality Criteria for Water, July 1976) PB-263943
                   See Appendix D for Methodology.
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                                      MIREX
                                   CAS# 2385-85-5
CRITERIA
Rationale
0.001 ng/L for freshwater and saltwater aquatic life.

Mirex is generally limited in its use to control the imported fire ant in the
southeastern United States, and it is always presented in bait.
   In experiments with field-collect crayfish, juvenile Procumbarus bland-
ingi were  exposed to  1  or 5 ng/L mirex for six to 144 hours and  then
transferred to clean water and observed for 10 days. After five days, 95
percent of the crayfish exposed to 1 ng/L mirex for 144 hours were dead.
Exposure to 5 ng/L for 6, 24, and 58 hours resulted in 26, 50, and 98 per-
cent mortality within the 10-day observation period in clean water. Several
similar experiments with other crayfish species revealed comparable mor-
tality  levels in exposures to low levels of mirex. For Promcambarus  hayi,
mirex tissue residue accumulations ranged from 940-  to 27,210-fold above
water concentrations after 48-hour exposures to 0.1 and 0.5(ig/L.
   In feeding experiments with 108 crayfish, one particle of mirex bait re-
sulted in  a  77  percent  mortality rate after  six   days. Comparable
experiments yielded similar results, indicating  that mirex is extremely
toxic  to the tested  species  of crayfish. Mortality and accumulation in-
creased with exposure  time. Field studies have  shown that mirex is
accumulated  through  the food chain, while additional data reveals that
mirex is transported from treated land into marsh and estuarine areas.
Mirex residues were found to increase with trophic levels of animals sam-
pled.  In addition, further studies documented mirex in areas not treated
with the insecticide. Mirex has been reported in fish from Lake Ontario,
Canada, although mirex is not registered for use in Canada.
   A summary of data available shows a mosaic of effects. Crayfish and
channel catfish survival is affected by mirex in the water or by ingestion of
the bait particles. Bioaccumulation is well established for a wide variety of
organisms. Mirex is very persistent in bird tissue.  Considering the extreme
toxicity and potential for bioaccumulation, every  effort should be made to
keep mirex bait particles out of water containing aquatic  organisms, and
water concentrations should not exeed 0.001 ng/L mirex. This value is
based upon an application  factor of 0.01 applied to  the lowest levels at
which effects  on crayfish have been observed.
   Data on which to base a marine criterion involve several estuarine and
marine crustaceans. A concentration of 0.1 ng/L mirex was lethal to juve-
nile pink  shrimp  (Penaeus duorarum) in a three-week exposure. Reduced
survival of the mud crab (Rhithropanopeus harrisii) was observed in 0.1
Hg/L mirex. In three of four 28-day seasonal flow-through experiments, re-
duced survival of Callinectes sapidus, Penaeus duorarum, and grass shrimp
(Palaemonetes  pugio), at levels of 0.12 ng/L in summer, 0.06 ng/L in fall, and
0.09 ng/L in winter, was observed.
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                     Effects of mirex on estuahne and marine crustaceans were observed af-
                  ter considerable time  had elapsed,  so that length of exposure  is an
                  important consideration for this chemical. This may not be the case in
                  fresh water since the crayfish were affected within 48 hours. Therefore, a
                  three- to four-week exposure might be considered  acute; and by applying
                  an application factor of 0.01 to reasonable average of toxic effect levels as
                  summarized above, a recommended marine criterion of 0.001 jig/L results.
                  (Quality Criteria for Water, July 1976) PB-263943
                  See Appendix D for Methodology.
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                             NAPHTHALENE
                                  CAS# 91-20-3
CRITERIA
Aquatic Life       The available data for naphthalene indicate that acute and chronic toxicity
                   to freshwater aquatic life occurs at concentrations as low as 2,300 and 620
                   Hg/L, respectively, and would occur at lower concentrations among spe-
                   cies that are more sensitive than those tested.
                      The available data also indicate that acute toxicity to saltwater aquatic
                   life occurs at concentrations as low as  2,350 jig/L and would occur at
                   lower concentrations among species that are more sensitive than  those
                   tested. No data are available concerning the chronic toxicity of naphtha-
                   lene to sensitive saltwater aquatic life.

Human Health    Using the present guidelines, a satisfactory criterion cannot be derived at
                   this time because of insufficient available data.
                   (45 F.R. 79318, November 28,1980)
                   See Appendix B for Aquatic Life Methodology.
                   See Appendix C for Human Health Methodology.
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                                     NICKEL
                                   CAS# 7440-02-0
CRITERIA
Summary
National Criteria
Not to exceed 75 ug/L in salt water.
8.3 ng/L for saltwater aquatic life.
Freshwater criteria are hardness dependent. See text.

Acute values with 21 freshwater species in 18 genera range from 1,101
ug/L for a cladoceran to 43,240 ug/L for a fish. Fishes and invertebrates
are both spread throughout the range of sensitivity. Acute values with four
species are significantly correlated with hardness. Data are available con-
cerning the chronic toxicity of nickel to two invertebrates and two fishes in
fresh water. Data available for two species indicate that chronic toxicity de-
creases as hardness increases. The measured chronic values ranged from
14.77 ug/L for Daphnia magna in soft water to 526.7 ug/L for the fathead
minnow (Pimephales promelas) in hard water. Five  acute-chronic ratios are
available for two species in soft and hard water and range from 14 to 122
Hg/L.
   Nickel appears to be quite toxic to freshwater algae, with concentra-
tions as low as 50 ug/L producing significant inhibition. Bioconcentration
factors for nickel range from 0.8 for fish muscle to 193 for a cladoceran.
   Acute values for 23 saltwater  species in 20 genera range from 151.7
Ug/L for mysid juveniles to 1,100,000 ug/L for juveniles and adults of a
clam. The acute values for the four species of fish  range from 7,598 to
350,000 ug/L. Nickel's acute toxicity appears to be  related to salinity and is
species-dependent.
   An acceptable chronic test on nickel has been  conducted on only one
saltwater species, Mysidopsis bahia. In it, chronic exposure to 141 ug/L and
greater  resulted in reduced survival and  reproduction;  the measured
acute-chronic ratio was 5.478.
   Bioconcentration factors in  saltwater range from 261.8 for an oyster to
675 for a brown alga.

The  procedures described in the "Guidelines for Deriving Numerical Na-
tional Water Quality Criteria for the Protection of  Aquatic Organisms and
Their Uses" indicate that, except possibly where a locally important spe-
cies  is very sensitive, freshwater aquatic organisms and their uses  should
not  be affected unacceptably  if the  four-day average concentration of
nickel (in ug/L) does not exceed the numerical value given by
                      _ (0.8460[ln(hardness)]+1.1645)
                      s
more than once every three years on the average and if the one-hour
average concentration (in ug/L)  does not  exceed  the numerical value
given by
                       (0.8460[ln(hardness)]+3.3612)
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                   more than  once every three years on  the  average.  For example,  at
                   hardnesses of 50,  100, and 200  mg/L as CaCOj,  the four-day average
                   concentrations of nickel are 88, 160, and  280 tig/L, respectively, and the
                   one-hour average concentrations are 790,1400, and 2500 ng/L.
                       The procedures described in the guidelines indicate that, except possi-
                   bly where a locally important species is very  sensitive, saltwater aquatic
                   organisms and their uses should not be affected unacceptably if the four-
                   day average concentration of nickel does not exceed 8.3 ng/L more  than
                   once every three years on the average and if the one-hour average concen-
                   tration does not exceed 75 ng/L more than once every three years on the
                   average.
                       Three years is the  Agency's best scientific judgment of the average
                   amount of time aquatic ecosystems should be provided between excur-
                   sions. The resiliences of ecosystems and their abilities to recover differ
                   greatly, however, and site-specific, allowed excursion frequencies can be
                   established if adequate justification is provided.
                       When developing  water  quality-based permit  limits and  designing
                   waste treatment facilities, criteria must be applied to an appropriate was-
                   teload allocation model. Dynamic models are preferred, but limited data or
                   other considerations might make their use impractical; therefore, regula-
                   tory programs must rely on a steady-state model.

Human Health    Human health  criteria were recalculated using Integrated Risk Informa-
                   tion System (IRIS) to reflect  available  data as of 12/92  (57 F.R. 60911).
                   Recalculated IRIS values for nickel are 610 ^g/L for ingestion of contami-
                   nated water and organisms and 4,600 ng/L for ingestion of contaminated
                   aquatic organisms only.
                    (45 F.R. 79337, November 28,1980) (51 F.R. 43665, December 3,1986)
                    (57 F.R. 60911, December 22,1992)
                    See Appendix A for Aquatic Life Methodology.
                    See Appendix C for Human Health Methodology.
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                          NITRATES/NITRITES
                                  CAS# 14797-55-8
CRITERIA
Introduction
Rationale
10 mg/L nitrate nitrogen (N) for domestic water supply (health).

Two gases — molecular nitrogen and nitrous oxide — and five forms of
nongaseous, combined nitrogen — amino and amide groups, ammonium,
nitrite, and nitrate — are important in the nitrogen cycle. The amino and
amide groups are found in soil organic matter and as constituents of plant
and animal protein. The ammonium ion either is released  from protei-
naceous organic matter and urea or is synthesized in industrial processes
involving atmospheric nitrogen fixation. The nitrite ion is formed from the
nitrate or the ammonium ions by certain microorganisms found in soil,
water, sewage, and the digestive tract. The nitrate ion is formed by the
complete oxidation of ammonium ions by soil or water microorganisms.
This process, known as denitrification, takes place when nitrate-containing
soils become anaerobic and the conversion to nitrite, molecular nitrogen,
or nitrous oxide occurs; in some instances, ammonium ions are produced.
In oxygenated natural water systems, nitrite is rapidly oxidized to nitrate.
Growing plants assimilate nitrate or ammonium ions and convert them to
protein.
    Among the major point sources of nitrogen entry into waterbodies are
municipal and industrial wastewaters, septic  tanks, and  feed  lot dis-
charges. Diffuse sources of nitrogen include farm-site fertilizer and animal
wastes, lawn fertilizer, leachate from waste disposal in dumps or  sanitary
landfills, atmospheric fallout, nitric oxide and nitrite discharges from auto-
mobile exhausts and other combustion processes, and losses from natural
sources such as mineralization of soil organic matter. Water reuse  systems
in some fish hatcheries employ a nitrification process for ammonia reduc-
tion; this can result in exposure of hatchery fish to elevated levels of nitrite.

In quantities normally found in food or feed, nitrates become toxic only
under conditions in which they are, or may be, reduced to nitrites. Other-
wise, at "reasonable" concentrations, nitrates are rapidly excreted in the
urine.  High  intake  of  nitrates constitutes  a hazard primarily to
warmblooded animals under conditions favorable to their reduction to ni-
trite. Under certain circumstances, nitrate can be reduced to nitrite in the
gastrointestinal tract, which  then reaches the bloodstream and reacts di-
rectly with  hemoglobin to  produce methemoglobin, with  consequent
impairment of oxygen transport.
    The reaction of nitrite with hemoglobin can be hazardous in infants
under 3 months of age. Serious and occasionally fatal poisonings in infants
have occurred following ingestion of untreated well waters shown to con-
tain nitrate at concentrations greater than 10 mg/L nitrate/nitrogen (N).
High nitrate concentrations frequently are found in shallow farm and rural
community wells, often as the result of inadequate protection from barn-
yard drainage or from septic tanks. Increased concentrations of nitrates

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                  also have been found in streams from farm tile drainage in areas of intense
                  fertilization and farm crop production.
                     The differences in susceptibility to methemoglobina are not yet under-
                  stood. They appear,  however,  to be related  to a combination of factors
                  including  nitrate concentration, enteric bacteria, and the  lower acidity
                  characteristic of the  digestive  system of baby mammals.  Methemoglo-
                  binemia symptoms and other toxic effects  were observed  when high
                  nitrate well waters containing pathogenic bacteria were fed to laboratory
                  mammals. Conventional water treatment has no significant effect on ni-
                  trate removal from water.
                     Because  of the  potential risk of methemoglobinemia to bottle-fed in-
                  fants, and in view of the absence of substantiated physiological effects at
                  nitrate concentrations below 10 mg/L nitrate/nitrogen, this level is the cri-
                  terion  for  domestic  water  supplies.  Waters with nitrite/nitrogen
                  concentrations over 1 mg/L should not be used for infant feeding. Waters
                  with a significant nitrite concentration usually would be heavily polluted
                  and probably bacteriologically unacceptable.
                     Quality Criteria for Water, July 1976, provides data for exposed fishes.
                  This data concludes that

                     1.  Levels of nitrate/nitrogen at or below 90 mg/L would have no
                         adverse effects on warmwater fish.

                     2.  Nitrite/ nitrogen at or below 5 mg/L should be protective of most
                         warmwater fish.

                     3.  Nitrite / nitrogen at or below 0.06 mg / L should be protective of
                         salmonid fishes.

                     These  levels are not known to occur or would be unlikely to occur in
                  natural surface waters. Recognizing that concentrations of nitrate or nitrite
                  that  would exhibit toxic effects on warmwater fish could rarely occur in
                  nature, restrictive criteria are not recommended.
                  (Quality Criteria for Water, July 1976) PB-263943
                  See Appendix D for Methodology.
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                             NITROBENZENE
                                   CAS# 98-95-3
CRITERIA

Aquatic Life
Human Health
The available data for nitrobenzene indicate that acute toxicity to freshwa-
ter aquatic life occurs at concentrations as low as 27,000 ng/L and would
occur at lower concentrations among species that are more sensitive than
those tested. No definitive data are available concerning the chronic toxic-
ity of nitrobenzene to sensitive freshwater aquatic life.
   The available data for nitrobenzene indicate that acute toxicity to salt-
water aquatic life occurs at concentrations as low as 6,680 ng/L and would
occur at lower concentrations among species that are more sensitive than
those tested. No definitive data are available concerning the chronic toxic-
ity of nitrobenzene to sensitive saltwater aquatic life.

Human health criteria were recalculated using Integrated Risk Informa-
tion  System (IRIS) to reflect available  data as of  12/92 (57 F.R. 60848).
Recalculated IRIS values for nitrobenzene  are 17.0 ng/L for ingestion of
contaminated water and organisms and 1,900 ng/L for ingestion of con-
taminated aquatic organisms only.
   Using available organoleptic data, the estimated level is 30 ng/L to
control undesirable taste and odor qualities of ambient  water. Organolep-
tic data do have limitations as a basis for establishing a water quality
criterion, however, but no demonstrated relationship  to potentially  ad-
verse effects on human health.
   The U.S. EPA is currently developing Acceptable Daily Intake (ADI) or
Verified Reference Dose (RfD) values for agencywide use for this chemical.
The new value should be substituted when it becomes available. The Janu-
ary 1986 draft Verified Reference Dose document cites an RfD of .0005
mg/kg/day for nitrobenzene.
                   (45 F,R, 79318, November 28,1980)
                   See Appendix C for Human Health Methodology.
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                             NITROPHENOLS
CRITERIA
Aquatic Life
The available data for nitrophenols indicate that acute toxicity to freshwa-
ter aquatic life occurs at concentrations as low as 230 ng/L and would
occur at lower concentrations among species that are more sensitive than
those tested. No data are available concerning the chronic toxicity of ni-
trophenols to sensitive freshwater aquatic life but toxicity to one species of
algae occurs at concentrations as low as 150 ng/L.
   The available data for nitrophenols indicate that acute toxicity to salt-
water aquatic life occurs at concentrations as low as 4,850 ng/L and would
occur at lower concentrations among species that are more sensitive than
those tested. No data are available concerning the chronic toxicity of ni-
trophenols to sensitive saltwater aquatic life.
Human Health
2,4-Dinitro-O-Cresol  (2-Methyl-4,6-Dinitrophenol) 534-52-1

                   Values to protect human health from exposure to 2,4-dinitro-o-cresol are
                   13.4 ng/L  through ingestion of contaminated water and organisms and
                   765 ng/L through ingestion of contaminated organisms only.

2,4-Dinitrophenol 51-28-5

                   Human health criteria were recalculated using Integrated Risk Informa-
                   tion System (IRIS) to reflect available data as of 12/92  (57 F.R. 60848).
                   Recalculated IRIS values for 2,4-dinitrophenol are 70 ng/L for ingestion of
                   contaminated water and organisms and 14,000 ng/L for ingestion of con-
                   taminated aquatic organisms only.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60848, December 22,1992)
                   See Appendix C for Human Health Methodology.
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176

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                             NITROSAMINES
                                  CAS# 35576-91-1
CRITERIA
Aquatic Life      The available data for nitrosamines indicate that acute toxicity to freshwa-
                   ter aquatic life occurs at concentrations as low as 5,850 ng/L and would
                   occur at lower concentrations among species that are more sensitive than
                   those tested. No data are available concerning the chronic toxicity of ni-
                   trosamines to sensitive freshwater aquatic life.
                      The available data for nitrosamines indicate that acute toxicity to salt-
                   water aquatic life occurs at concentrations as low as 3,300,000 ng/L and
                   would occur at lower concentrations among species that are more sensitive
                   than those tested. No data are available concerning the chronic toxicity of
                   nitrosamines to sensitive saltwater aquatic life.

Human Health

N-nitrosodiethylamine  55-18-5

                   For the maximum protection of human health from the potential carcino-
                   genic effects  of exposure  to   N-nitrosodiethylamine  and  all  other
                   nitrosamines, except those listed below, through ingestion of contaminated
                   water and contaminated aquatic organisms, the ambient water concentra-
                   tions should be zero, based on  the  nonthreshold assumption  for this
                   chemical. However,  zero level may not be attainable at the present time.
                   Therefore, the levels that can result in incremental increase of cancer risk
                   over a lifetime are estimated at 10,10", and 10" . The corresponding rec-
                   ommended criteria are 8.0 ng/L, 0.8 ng/L, and 0.08 ng/L, respectively. If
                   these estimates are made for consumption of aquatic organisms only, ex-
                   cluding consumption of water, the levels are 12,400 ng/L,  1,240 ng/L, and
                   124 ng/L, respectively.

N-nitrosodimethylamine   62-75-9

                   For the maximum protection of human health from the potential carcino-
                   genic effects of exposure to N-nitrosodimethylamine through ingestion of
                   contaminated water and contaminated  aquatic organisms, the  ambient
                   water concentrations should be zero, based on the nonthreshold assump-
                   tion for this chemical. However,  zero level may not be attainable at the
                   present time. Published human health criteria were recalculated using In-
                   tegrated  Risk  Information System (IRIS) to reflect available data as of
                   12/92 (57 F.R. 60914). Therefore, the levels that may result in incremental
                   increase of cancer risk over the lifetime are estimated at 10"5,10"6, and 10'7.
                   The  corresponding recommended criteria are 0.0069 ng/L, 0.00069 ug/L,
                   and  0.000069 ng/L, respectively. If these estimates are made for consump-
                   tion of aquatic organisms only, excluding consumption of water, the levels
                   are 81 ng/L, 8.1 ng/L, and 0.81 ng/L, respectively.

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N-nitrosodibutylamine  924-16-3
                   For the maximum protection of human health from the potential carcino-
                   genic effects  of exposure to N-nitrosodibutylamine through ingestion of
                   contaminated water and contaminated aquatic organisms,  the ambient
                   water concentrations should be zero, based on the nonthreshold assump-
                   tion for this chemical. However, zero  level may not be attainable at the
                   present time. Therefore, the levels that may result in incremental increase
                   of cancer risk over the lifetime are estimated at 10"5,10"6, and 10~7. The cor-
                   responding recommended criteria are 64 ng/L, 6.4 ng/L, and 0.64 ng/L,
                   respectively. If these estimates are made for consumption of aquatic organ-
                   isms only, excluding consumption of water, the levels are 5,868 ng/L, 587
                   ng/L, and 58.7 ng/L, respectively.

N-nitrosopyrrolidine   930-55-2
                   For the maximum protection of human health from the potential carcino-
                   genic effects of exposure to  N-nitrosopyrrolidine through  ingestion of
                   contaminated water and contaminated aquatic organisms,  the ambient
                   water concentrations should be zero, based on the nonthreshold assump-
                   tion for this chemical. However, zero  level may not be attainable at the
                   present time. Therefore, the levels that may result in incremental increase
                   of cancer risk over a lifetime are estimated at 10", 10", and 10", The corre-
                   sponding recommended  criteria are 160  ng/L, 16 ng/L, and 1.6 ng/L,
                   respectively. If these estimates are made for consumption of aquatic organ-
                   isms only,  excluding consumption of water, the levels are 919,000 ng/L,
                   91,900 ng/L, and 9,190 ng/L, respectively.

N-nitrosodiphenylamine  86-30-6
                   For the maximum protection of human health from the potential carcinogenic
                   effects of exposure to N-nitrosodiphenylamine through ingestion of contami-
                   nated  water and  contaminated  aquatic  organisms, the ambient water
                   concentrations should be zero, based on the nonthreshold assumption for this
                   chemical. However, zero  level  may not be attainable at  the present time.
                   Therefore, the levels that  may result in incremental increase of cancer risk
                   over the lifetime are estimated at 10"5' 10"6, and  10"7. Published human
                   health criteria were recalculated using IRIS to reflect available data as of
                   12/92 (57  F.R. 60914). Recalculated IRIS values  for N-nitrosodipheny-
                   lamine are 5.0 ug/L for ingestion of contaminated water and  organisms
                   and 16.0 ng/L for ingestion of contaminated aquatic organisms only.

N-nitrosodi-n-propylamine  62-164-7
                   For the maximum protection of human health from the potential carcino-
                   genic effects of exposure  to N-nitrosodi-n-propylarnine through ingestion
                   of contaminated water and contaminated  aquatic organisms, the ambient
                   water concentrations should be zero, based on the nonthreshold assump-
                   tion for this  chemical.  However, zero  level may not be attainable at the
                   present time. Therefore, the levels that may result in incremental increase
                   of cancer risk over the lifetime are estimated at 10"5,10"6, and 10"7. Human
                   health criteria were calculated using IRIS to reflect available  data as of
                   12/92 (57 F.R. 60890). Calculated values are based on 10"6 risk level for N-
                   nitrosodi-n-propylamine  are  0.005 ug/L  for ingestion  of contaminated
                   water and organisms and 1.4 ug/L for ingestion of contaminated aquatic
                   organism only.

                    (45 F.R. 79318, November 28,1980) (57 F.R. 60890, December 22,1992.
                    See Appendix C for Human Health Methodology.
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                            OIL AND  GREASE
CRITERIA
Domestic Water
Supply           Virtually free from oil and grease, particularly from the tastes and odors
                   that emanate from petroleum products.

Aquatic Life          1.  0.01 of the lowest continuous flow 96-hour LC50 to several
                          important freshwater and marine species, each having a
                          demonstrated high susceptibility to oils and petrochemicals.

                       2.  Levels of oils or petrochemicals in the sediment that cause
                          deleterious effects to the biota should not be allowed.

                       3.  Surface waters shall be virtually free from floating nonpetroleum
                          oils of vegetable or animal origin as well as petroleum-derived oils.
INTRODUCTION

                   An estimated 5 to 10 million metric tons of oil enter the marine environ-
                   ment annually. A major difficulty encountered in setting criteria for oil and
                   grease is categorization. Chemicals are not divided into  categories but in-
                   clude thousands of organic compounds with varying physical, chemical,
                   and toxicological properties. They can be either volatile or nonvolatile, sol-
                   uble or insoluble, and persistent or easily degraded.

Rationale         Field and laboratory evidence have demonstrated both acute lethal toxic-
                   ity and long-term sublethal toxicity  of oils to aquatic organisms. Events
                   such as the Tampico Maru wreck of 1957 in Baja, California, and the No. 2
                   fuel oil spill in West  Falmouth,  Massachusetts, in 1969,  both of which
                   caused immediate death to a wide variety of organisms, illustrate the le-
                   thal toxicity that may be attributed to oil  pollution. Similarly, a gasoline
                   spill in South Dakota in November 1969 was reported to have caused im-
                   mediate death to the majority of freshwater invertebrates and 2,500 fish, 30
                   percent of which were native species of trout. Because of the wide range of
                   compounds included in the category of oil, establishing meaningful 96-
                   hour LC50  values for oil  and grease  without specifying  the product
                   involved is impossible. The most susceptible category of  organisms, the
                   marine larvae, appear to be intolerant of petroleum pollutants, particularly
                   the water soluble compounds, at concentrations as low as 0.1  mg/L.
                       The long-term sublethal effects of oil pollution refer to  interferences
                   with cellular and physiological processes such as feeding and reproduc-
                   tion and do not lead to immediate death of the organism. Disruption of
                   such behavior apparently can result from petroleum product  concentra-
                   tions as low as 10 to 100 tig/L.

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                      Summaries of some of the sublethal toxicities for various petroleum
                   pollutants and aquatic species are contained in the 1976 criteria. In addi-
                   tion to sublethal effects reported at the 10 to 100 ng/L level, petroleum
                   products can harm aquatic life at concentrations as low as 1 ng/L.
                      Bioaccumulation of petroleum  products presents two especially im-
                   portant public health problems: (1) the tainting of edible, aquatic species,
                   and (2) the possibility of edible marine organisms incorporating the high
                   boiling, carcinogenic polycyclic aromatics in their tissues. Research shows
                   that O.Olmg/L of crude oil caused tainting in oysters. Concentrations as
                   low as 1 to 10 ng/L could lead to tainting within very short periods of
                   time. Chemicals  responsible  for cancer in animals and humans (such as
                   3,4-benzopyrene) occur in crude oil. Also, marine organisms are capable of
                   incorporating potentially carcinogenic  compounds  into their body fat
                   where the compounds remain unchanged.
                      Oil pollutants may also be incorporated into sediments.  Evidence
                   shows  that once this occurs  in the sediments below the aerobic  surface
                   layer,  petroleum oil can remain unchanged  and toxic for  long periods,
                   since its rate of baterial  degradation is slow. For example. No. 2 fuel oil in-
                   corporated into the sediments after the West  Falmouth spill persisted for
                   over a  year, and  even began spreading in the form of oil-laden sediments
                   to more distant areas that had remained unpolluted immediately after the
                   spill. The persistence of unweathered oil within the sediment could have a
                   long-term effect on the structure of the benthic community or cause the de-
                   mise of specific sensitive important species.
                      Reports show that 0.01 mg/L oil produced deformed and inactive flat-
                   fish larvae and  inhibition or delay of cellular division in algae by oil
                   concentrations of 10"4 to 10"1 mg/L. A reduction in the chemotactic percep-
                   tion of food by the snail, Nassarius obsoletus, at kerosene concentrations of
                   0.001 to 0.004 mg/L was also reported. Decreased survival and fecundity
                   in worms were reported at concentrations of 0.01 to 10 mg/L of detergent.
                      Because of the great variability in the toxic properties of oil, estab-
                   lishing a numerical criterion applicable to all types of oil is difficult. Thus,
                   an application factor of 0.01 of the 96-hour LC50 as determined by using
                   continuous flow with a sensitive resident species should be employed for
                   individual petrochemical components.
                      Toxicological data is sparse on the ingestion of the components of re-
                   finery  wastewaters by  humans or by test animals. Any tolerable health
                   concentrations for petroleum-derived substances far exceed the limits of
                   taste and odor. Since petroleum derivatives become organoleptically objec-
                   tionable at concentrations far below the human chronic toxicity, hazards to
                   humans will not likely arise from drinking oil-polluted waters. Oils of ani-
                   mal or vegetable origin generally are nontoxic to humans and aquatic life.
                      In view of the problem of petroleum oil incorporated in sediments, its
                   persistence and  chronic toxic potential, and the present lack of sufficient
                   toxicity data to  support specific criteria, oil concentrations in sediments
                   should not approach levels that cause deleterious effects to important spe-
                   cies or the bottom community as a whole.
                      Petroleum and nonpetroleum oils share some similar physical and
                   chemical properties.  Because they share common properties,  they may
                   cause  similar harmful  effects in  the aquatic environment  by forming a
                   sheen, film, or discoloration  on the water surface.  Like petroleum oils,
                   nonpetroleum oils may occur at four levels of the aquatic environment: (a)
                   floating on the surface, (b) emulsified in the water column, (c) solubilized,
                   and (d) settled on the bottom as a sludge. Analogous  to the grease balls
180

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from vegetable oil and animal fats are the tar balls of petroleum origin that
have been found in the marine environment or washed ashore on beaches.
   Oils of any kind can cause (a) drowning of water fowl because of loss
of buoyancy, exposure because of loss of insulating capacity of feathers,
and starvation and vulnerability  to predators because of lack of mobility;
(b) lethal effects on fish by coating epithelial surface of gills, thus prevent-
ing respiration; (c) potential fishkills resulting from biochemical oxygen
demand; (d) asphyxiation of benthic life forms when floating masses be-
come engaged with surface debris and settle on the bottom; an (e) adverse
aesthetic effects of fouled shorelines and beaches. These and other effects
have been documented in the U.S. Department of Health, Education and
Welfare report on Oil Spills Affecting the Minnesota and Mississippi Riv-
ers in  the 1975 Proceedings of the  Joint Conference on Prevention and
Control of Oil Spills.
   Oils of animal or vegetable origin generally are chemically nontoxic to
humans or aquatic life; however, floating sheens of such oils result in dele-
terious environmental effects described in this  criterion. Thus, surface
waters should be virtually free from floating nonpetroleum oils  of vegeta-
ble or animal origin.This same recommendation applies to floating oils of
petroleum origin, since they, to, may produce similar effects.
(Quality Criteria for Water, July 1976) PB-263943
See Appendix D for Methodology.
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182

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CRITERIA
                                 PARATHION
                                    CAS# 56-38-2
Aquatic Life
Summary
Freshwater —  1-hour average of 0.065 ng/L
              4-day average of 0.013 ng/L


The acute values for 37 freshwater species in 31 genera range from 0.04
jig/L for an early instar of a crayfish (Orconectes nais) to 5,230 ng/L for two
species  of tubificid  worms. For Daphnia magna, the chronic value and
acute-chronic ratio are 0.0990 ng/L and 10.10, respectively. Chronic toxic-
ity values are available for  two  freshwater  fish species, the bluegill
(Lepomis macrochirus) and the fathead minnow  (Pimephales promelas), with
chronic values of 0.24 ng/L and 6.3 ng/L, and acute-chronic ratios of 2,121
and 79.45, respectively. Two freshwater algae were affected by toxaphene
concentrations of 30 and 390 ug/L, respectively. Bioconcentration factors
determined with three fish species ranged from 27 to 573.
   The  acute values available for saltwater species are 11.5 and 17.8 ng/L
for the Korean shrimp, Palaemon  macrodactylus, and 17.8 ng/L for the
striped  bass (Morone saxatilis).  No  data are  available concerning the
chronic  toxicity of parathion to saltwater species, toxicity to saltwater
plants, or bioaccumulation by saltwater species. Some data indicate that
parathion is acutely lethal to commercially important saltwater shrimp at
concentrations as low as 0.24 ug/L. Measurement of acetylcholinesterase
(AChE)  in fish tissue might be useful for diagnosing fish kills caused by
parathion.
National Criteria The procedures described in the "Guidelines for Deriving Numerical Na-
                   tional Water Quality Criteria for the Protection of Aquatic Organisms and
                   Their Uses" indicate that, except possibly where a locally important spe-
                   cies is very sensitive, freshwater aquatic organisms and their uses should
                   not be affected unacceptably if the four-day average concentration of para-
                   thion does not exceed 0.013 ng/L more than once every three years on the
                   average and if the one-hour average concentration does not exceed 0.065
                   Hg/L more than once every three years on the average.
                       The procedures described in the guidelines require the availability of
                   specified data for the derivation of a criterion. A saltwater criterion for
                   parathion cannot be derived because very few of the required data are
                   available.
                       In the Agency's best scientific judgment,  three years is the average
                   time aquatic ecosystems should be provided between excursions. The re-
                   siliences of ecosystems  and  their abilities  to  recover differ  greatly,
                   however, and  site-specific allowed excursion  frequencies may be estab-
                   lished if adequate justification is provided.
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                      When developing water quality-based permit limits and for designing
                   waste treatment facilities, criteria must be based upon an appropriate was-
                   teload allocation model. Dynamic models are preferred; but if limited data
                   or other considerations might make their use impractical, rely on steady-
                   state models.
                   (51 F.R. 43665, December 3,1986)
                   See Appendix A for Aquatic Life Methodology.
184

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                 PENTACHLOROPHENOL (PCP)
                                   CAS# 87-86-5
CRITERIA
Summary
National Criteria
Not to exceed 13.0 ng/L in salt water.
7.9 ng/L for saltwater aquatic life.
Freshwater criteria are pH dependent. See text.

The acute and chronic toxicity of PCP to freshwater animals increased as
pH and dissolved oxygen concentration of the water decreased. Generally,
toxicity also increases with  increased temperature. The estimated acute
sensitivities of 36 species at pH  = 6.5 ranged from 4.355 ng/L for larval
common carp to 43,920  ng/L for a crayfish. At pH = 6.5, the lowest and
highest estimated chronic values of < 1.835 and 79.66 ng/L, respectively,
were obtained with different cladoceran species. Chronic toxicity  to fish
was affected by  the presence of impurities, with industrial-grade PCP be-
ing more toxic than purified samples. Mean acute-chronic ratios  for six
freshwater species ranged from 0.8945 to 15.79, but the mean ratios  for the
four most acutely sensitive species only ranged from 0.8945 to 5.035. Fresh-
water algae were affected by concentrations as  low as 7.5 ug/L, whereas
vascular plants were affected at 189 ng/L and above. Bioconcentration fac-
tors ranged from 7.3 to 1,066 for three species of fish.
   Acute toxicity values from tests with 18 species of saltwater animals,
representing 17  genera,  range from 22.63 ng/L  for  late yolk-sac larvae of
the Pacific herring (Clupea harengus pallasi) to 18,000 ng/L for adult blue
mussels (Mytllus edulis).  The  embryo and larval stages of invertebrates and
the late larval premetamorphosis stage of fish appear to be the most sensi-
tive life stages to PCP. With few exceptions, fish are more sensitive than
invertebrates to  PCP. Salinity, temperature, and  pH have a slight effect on
the toxicity of PCP to some saltwater animals.
   Life-cycle toxicity tests have been conducted with the sheepshead min-
now  (Cyprinodon variegatus) and  the  polychaete  worm  (Ophryotrocha
diadema). The chronic value  for the minnow is 64.31 ng/L and the acute-
chronic ratio is 6.873. Unfortunately, no statistical analysis of the worm test
data is available.
   The ECSOs for saltwater  plants range from 17.40 ng/L for the diatom,
Skeletonema costatum,  to 3,600  ng/L for the green alga (Dunaliella ter-
tiolecta). Apparent steady-state BCFs  are available  for the eastern  oyster
(Crassostrea virginica) and two saltwater fishes and range from 10 to 82.

The procedures  described in the  "Guidelines for Deriving Numerical Na-
tional Water Quality Criteria for the Protection of Aquatic Organis'ms and
Their Uses"  indicate that, except possibly where a  locally important spe-
cies is very sensitive, freshwater  aquatic organisms and their uses should
not be affected  unacceptably if  the four-day average  concentration (in
Hg/L) of pentachlorophenol  does not exceed the numerical value given by
                          e[1.005(pH)-5.290]

                                                             185

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                   more than once every  three years on the average and if the one-hour
                   average concentration  (in ng/L) does not  exceed the numerical value
                   given by
                                               e[1.005(pH)-4.830]

                   more than once every three years on the average. For example, at pH = 6.5,
                   7.8, and 9.0, the four-day average concentrations of pentachlorophenol are
                   3.5,13, and 43 ug/L, respectively, and the one-hour average concentrations
                   are 5.5,20, and 68 jig/L. At pH = 6.8, a pentachlorophenol concentration of
                   1.74 jig/L caused a 50 percent reduction in the growth of yearling sockeye
                   salmon (Oncorhynchus nerka) in a 56-day test.
                       The procedures described in the guidelines indicate that, except possi-
                   bly where a locally important species is very sensitive, saltwater aquatic
                   organisms and their uses should not be affected unacceptably if the four-
                   day average concentration of pentachlorophenol does not exceed 7.9 ng/L
                   more than once every three years on the average and if the one-hour aver-
                   age concentration does not exceed 13 ng/L more than once  every three
                   years on the average.
                       In  the Agency's best scientific judgment, three years is the average
                   time aquatic ecosystems should be provided between excursions. The re-
                   siliences  of ecosystems  and  their abilities to  recover differ greatly,
                   however, and site-specific allowed excursion frequencies may be  estab-
                   lished if adequate justification is provided.
                       When developing water quality-based permit limits and designing
                   waste treatment facilities, criteria must be based upon an appropriate was-
                   teload allocation model. Dynamic models are preferred, but if limited data
                   or other considerations might make their use impractical, rely on steady-
                   state models.

                   (51 F.R. 43665, December 3,1986)
                   See Appendix A for Aquatic Life Methodology.

Human Health   Human health criteria  were recalculated using Integrated Risk Informa-
                   tion System (IRIS) to reflect data available as of 12/92 (57  F.R. 60840).
                   Recalculated IRIS values for pentachlorophenol are 0.28 ng/L for ingestion
                   of contaminated water  and organisms and 8.2 ng/L for ingestion of con-
                   taminated aquatic organisms only.
                       Using available organoleptic  data, the estimated  level is  30 ng/L to
                   control undesirable taste and odor qualities of ambient water.  Organolep-
                   tic data do have  limitations as a basis for establishing a water quality
                   criterion but no demonstrated  relationship to potentially adverse effects
                   on human health.
                    (45 F.R. 79318, November 28,1980) (57 F.R. 60848, December 22,1992)
                    See Appendix C for Human Health Methodology.
186

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                                        PH
CRITERIA

pH Range
Introduction
   •  5-9 for domestic water supplies.
   •  6.5-9.0 for freshwater aquatic life.
   •  6.5-8.5 for marine aquatic life (but not more than 0.2 units outside of
      normally occurring range).

"pH" measures the hydrogen ion activity in a water sample. It is mathe-
matically related to hydrogen ion activity according to the  expression:
pH = -LogjQ (H+), where (H ) is the hydrogen ion activity.
   The pH of natural waters is a measure of acid base equilibrium
achieved by the various dissolved compounds, salts, and gases. The prin-
cipal system regulating pH in natural waters is the carbonate system,
which is composed of carbon dioxide (COz), carbonic acid (hkCOa), bicar-
bonate ion (HCOa),  and carbonate ions (COa).  The  interactions and
kinetics of this system have been described by scientists.
   pH is an important factor in the chemical and  biological systems of
natural waters. The degree of dissociation of weak acids or bases is af-
fected by changes in pH, which is important because the toxicity of many
compounds is affected by the degree of dissociation. One such example is
hydrogen cyanide (HCN): cyanide toxicity to fish increases as the pH is
lowered because the chemical equlibrium  is shifted toward an increased
concentration of HCN. Similar results have been shown for hydrogen sul-
fide (H2S).
   pH also affects the solubility of metal compounds contained in bottom
sediments or as suspended material. For example, laboratory equilibrium
studies under anaerobic conditions indicated  that pH was an important
parameter involved in releasing manganese from bottom sediments.
   The pH of a waterbody does not indicate ability to neutralize additions
of acids or bases without appreciable change. This  characteristic, termed
"buffering capacity," is controlled by the amounts of alkalinity and acidity
present.
                    (Quality Criteria for Water, July 1976) PB-263943
                    See Appendix D for Methodology.
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188

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                                   PHENOL
                                   CAS# 108-95-2
CRITERIA

Aquatic Life
Human Health
The available data for phenol indicate that acute and chronic toxicity to
freshwater aquatic life occurs at concentrations as low as 10,200 ng/L and
2,560 ug/L, respectively, and would occur at lower concentrations among
species that are more sensitive than those tested.
   The available data for phenol indicate that toxicity to saltwater aquatic
life occurs at concentrations as low as 5,800 ng/L and would  occur at
lower concentrations among species that are more sensitive  than those
tested. No data are available concerning the chronic toxicity of phenol to
sensitive saltwater aquatic life.

Published human health criteria were recalculated using Integrated Risk
Information System  (IRIS)  to  reflect  data  available  as  of  12/92
(57 F.R. 60912). Recalculated IRIS values for phenol are 21,000 ug/L for in-
gestion of contaminated water and organisms  and 4,600,000 ng/L for
ingestion of contaminated aquatic organisms only.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60912, December 22,1992)
                   See Appendix C for Human Health Methodology.
                                                                                189

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190

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                              PHOSPHORUS
                                  CAS# 7723-14-0
CRITERION
Introduction
0.10  ng/L yellow (elemental) phosphorus  for estuarine and saltwater
aquatic life.

Phosphorus in its elemental form is particularly toxic and subject to bioac-
cumulation in much the same way as mercury. Phosphorus as phosphate,
however, is one of the major nutrients required for plant nutrition and es-
sential for life. In excess of a critical concentration, phosphates stimulate
plant growths.
   During the past 30 years, the belief  has developed  that increasing
standing crops of aquatic plants, which often interfere with water uses and
are nuisances to humans, frequently are caused by increasing phosphorus
supplies. Such phenomena are associated  with a condition of accelerated
eutrophication or aging of waters. Phosphorus is not the sole cause of eu-
trophication, but evidence suggests that frequently it is the key element of
all elements required by freshwater plants. Generally,  it is present in the
least amount relative to need. Therefore, an increase in phosphorus allows
use of other already present nutrients for plant growth. Further, of all ele-
ments required for plant growth in the water environment, phosphorus is
most easily controlled by humans.
   Large deposits of phosphate rock are found near the western shore of
central Florida, as well as in a number of other States. Deposits in Florida
are found in the form of pebbles embedded in a matrix of clay and sand
that  vary in  size  from  fine sand to about the size of a human foot. The
phosphate rock beds lie within a few  feet of the surface and are mined by
using hydraulic water jets and a washing  operation  that separates the
phosphates from  waste materials, a process  similar to  strip-mining. Flor-
ida,  Idaho, Montana, North Carolina, South Carolina, Tennessee, Utah,
Virginia, and Wyoming all mine phosphate.
   Phosphates enter waterways from several different sources. The hu-
man body excretes about one pound per year of phosphorus, expressed as
"P."  The use of phosphate detergents and other domestic phosphates in-
creases  the per capita contribution  to about  3.5 pounds per year of
phosphorus as P. Some industries, such as potato processing, have waste-
waters high in phosphates. Cropland, forestland, and idle and urban land
contribute varying amounts of phosphorus-diffused sources in drainage to
watercourses: surface runoff of rainfall, effluent from tile  lines, or return
flow from irrigation. Other contributing sources are cattle feedlots, concen-
trations of domestic or wild  ducks,  tree leaves, and fallout from the
atmosphere.
   Evidence indicates that high phosphorus concentrations are associated
with accelerated eutrophication of waters when other  growth-promoting
factors are present; aquatic plant problems develop in reservoirs and other
standing waters with phosphorus values lower than those critical in flow-
ing streams; reservoirs  and lakes collect phosphates from influent streams

                                                             191

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                   and store a portion of them within consolidated sediments, thus serving as
                   a phosphate sink; and phosphorus concentrations critical to noxious plant
                   growth vary. Therefore, nuisance growths may result from a particular
                   concentration of phosphate in one geographical area but not in another.
                      The amount or percentage of inflowing nutrients that may be retained
                   by a lake or reservoir is variable and will depend upon the following:

                      • The nutrient loading to the lake or resevoir;

                      • The volume of the euphotic zone;

                      • The extent of biological activities;

                      • The detention time within a lake basin or the time available for
                        biological activities; and

                      • The level of discharge from the lake or of the penstock from the
                        reservoir.

                      Once nutrients are combined within the aquatic ecosystem, their re-
                   moval is tedious and expensive. Phosphates are used by algae and higher
                   aquatic plants and excess may be stored within the plant cell. With decom-
                   position of the plant cell, some phosphorus may be released immediately
                   through bacterial action for recycling within the biotic community, while
                   the remainder may be deposited with sediments. Much of the material that
                   combines with  the  consolidated  sediments within  the lake bottom is
                   bound permanently and will not be recycled into the system.
Rationale
Elemental Phosphorus
                   Isom (1960) reported and LC50 of 0.105 mg/L at 48 hours and 0.025 mg/L
                   at 160 hours for bluegill sunfish (Lepomis macrochirus) exposed to yellow
                   phosphorus in distilled water at 26°C and pH 7. The 125- and 195-hour
                   LCSOs of yellow phosphorus to Atlantic cod (Gadus morhua) and Atlantic
                   salmon (Salmo salar) smolts in continuous-exposure experiments was 1.89
                   and 0.79 ng/L, respectively. No evidence of an incipient lethal level was
                   observed since the  lowest concentration of P4 tested  was 0.79  ng/L.
                   Salmon that were exposed to elemental phosphorus concentration of 40
                   Hg/L or less developed a distinct external red color and showed signs of
                   extensive hemolysis. The predominant features of ?4 poisoning in salmon
                   were external redness, hemolysis, and reduced hematocrits.
                      Following the opening of an elemental phosphorus production plant
                   in Long Harbour, Placentia Bay; Newfoundland, divers observed dead fish
                   upon the bottom throughout the harbor. Mortalities were confined to a
                   water depth of less than 18 meters. Visual evidence showed selective mor-
                   tality among benthos. Live mussels were found within 300 meters of the
                   effluent pipe, while all scallops within this area were dead.
                      Fish will concentrate elemental phosphorus from water containing as
                   little as 1 ng/L. In one set of experiments, a cod swimming in water con-
                   taining  1  ng/L  elemental  phosphorus for  18  hours  concentrated
                   phosphorus to 50 ng/L in muscle, 150 ng/kg in fatty tissue, and  25,000
                   Hg/kg in the  liver. The experimental findings showed that phosphorus is
                   quite stable in the fish tissues.
192

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                       The criterion of 0.10 ng/L elemental phosphorus for marine or estu-
                   arine waters in 1/10 of demonstrated lethal levels to  important marine
                   organisms and of levels found to result in significant bioaccumulation.

Phosphate Phosphorus

                   Although a total phosphorus criterion to control nuisance aquatic growths
                   is not presented, the following rationale to support such a criterion, which
                   currently is evolving, should be considered.
                       Total phosphate phosphorus concentrations in excess of 100 |ig/L P
                   may interfere with coagulation in water treatment plants. When such con-
                   centrations  exceed 25  jig/L  at the time of the  spring turnover on a
                   volume-weighted  basis in lakes  or reservoirs,  they  may occasionally
                   stimulate excessive (nuisance) growths of algae and other aquatic plants.
                   Algal growths inpart undesirable tastes and odors to water, interfere with
                   water treatment, become aesthetically unpleasant, and alter the chemistry
                   of the water supply. They contribute to the phenomenon of cultural eutro-
                   phication.
                       To prevent the development of biological nuisances and to control ac-
                   celerated or cultural eutrophication, total phosphates as phosphorus (P)
                   should not exceed 50 ng/L in any stream at the point where it enters any
                   lake or reservoir, nor 25 ng/L within the lake or reservoir. A desired goal
                   for the prevention of plant nuisances in streams or other flowing waters
                   not discharging directly to lakes  or impoundments is 100 ng/L total  P.
                   Most relatively uncontaminated lake districts are known to have surface
                   waters that contain from 10 to 30 ug/L total phosphorus as P.
                       The majority of the Nation's eutrophication problems are  associated
                   with lakes or reservoirs. Currently, more data support establishing a limit-
                   ing phosphorus level in those waters than in streams or rivers that do not
                   directly impact such water. Some natural conditions, also, would dictate
                   whether a more or less stringent phosphorus level should be considered.
                   Eutrophication problems may occur in waters where the phosphorus con-
                   centration is less than  that indicated previously.  Obviously, such waters
                   would need more stringent nutrient limits. Likewise, in some waters phos-
                   phorus is not now a limiting nutrient and the need for phosphorus limits is
                   substantially diminished.
                       Establishing a  phosphorus criterion for flowing  waters requires two
                   basic needs: one is to control the development of  plant nuisances within
                   the flowing water and, in turn, to control and prevent animal pests that
                   may become associated with such  plants; the other is to protect the down-
                   stream receiving waterway, regardless of its proximity in linear distance. A
                   portion of the phosphorus that enters a stream or other flowing waterway
                   eventually will reach a receiving lake or estuary either as a component of
                   the fluid mass, as bed load sediments  carried downstream, or as floating
                   organic materials  drifting just above  the streambed or floating on  the
                   water's surface. Superimposed on the loading from the inflowing water-
                   way, a lake  or estuary can receive additional phosphorus as fallout from
                   the air shed or as a direct introduction from shoreline areas.
                       Another method to control the inflow of nutrients,  particularly phos-
                   phates, into a lake is that of prescribing an annual loading to the receiving
                   water. Vollenweider suggests total phosphorus  loadings in grams  per
                   square meter of surface area per year as a critical level for eutrophic condi-
                   tions within the receiving waterway for a particular water volume where
                   the mean depth of the lake in meters is divided by the hydraulic detention

                                                                                 193

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                  Table 1.—Annual loadings.
MEAN OEPTH/HYDRAUUC
DETENTION TIME
(fntt«r«/yt«r)
0.5
1.0
2.5
5.0
7.5
10.0
25.0
50.0
75.0
100.0
OUGOTROPHIC OR
PERMISSIBLE LOADING
(grams/mttcr^/VMr)
0.07
0.10
0.16
0.22
0.27
0.32
0.50
0.71
0.87
1.00
EUTROPHIC OR CRITICAL
LOADING
(gramc/mtter^/yMr)
0.14
0.20
0.32
0.45
0.55
0.63
1.00
1.41
1.73
2.00
                  Source: \folf«nw«ld«r (1973).


                   time in years. Vollenweider's data suggest a range of loading values that
                   should result in oligotrophic lake water quality (see Table 1).
                      In some waterways, higher concentrations or loadings of total phos-
                   phorus do not produce eutrophy or lower concentrations or loadings of
                   total phosphorus may produce nuisance organisms. Therefore, waters now
                   containing less than the specified amounts of phosphorus should not be
                   degraded by the introduction of additional phosphates.
                      The following specific exceptions can reduce the threat of phosphorus
                   as a contributor to lake eutrophy:

                      • Naturally occurring phenomena may limit the development of
                        plant nuisances;

                      • Technological or cost-effective limitations may help control
                        introduced pollutants;

                      • Waters may be highly laden with natural silts or colors that reduce
                        the penetration of sunlight needed forplantphotosynthesis;

                      • Some waters' morphometric features — steep banks, great depth,
                        and substantial flows — contribute to a history of no plant
                        problems;

                      • Waters may be managed primarily for waterfowl or other wildlife;

                      • In some waters, a nutrient other than phosphorus limits plant
                        growth; the level and nature of such a limiting nutrient would not
                        be expected to increase to an extent that would influence
                        eutrophication; and

                      • In some waters, phosphorus control cannot be sufficiently effective
                        under present technology to make phosphorus the limiting
                        nutrient.

                      No national criterion is presented for phosphate phosphorus for the
                   control of eutrophication.
194
                   (Quality Criteria for Water, July 1976) PB-263943
                   See Appendix D for Methodology.

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                         PHTHALATE  ESTERS
CRITERIA

Aquatic Life
Human Health
The available data for phthalate esters indicate that acute and chronic tox-
icity to freshwater aquatic life occurs at concentrations as low as 2,000 and
160 M-g/L, respectively, and would occur at lower concentrations among
species that are more sensitive than those tested.
   The available data for phthalate esters indicate that acute toxicity to
saltwater aquatic life occurs at concentrations as low as 2,000 ng/L and
would occur at lower concentrations among species that are more sensitive
than those tested. No data are available concerning the chronic toxicity of
phthalate esters to sensitive saltwater aquatic life, but toxicity to one spe-
cies of algae occurs at concentrations as low as 160 ^g/L.

Human health criteria were recalculated using Integrated Risk Informa-
tion System (IRIS) to  reflect available data  as of 12/92 (57 F.R.  60913).
Recalculated IRIS values for diethyl phthalate are 23,000 ng/L for inges-
tion of contaminated water and organisms and 120,000 ng/L for ingestion
of contaminated aquatic organisms only.
   Human health criteria were recalculated using IRIS to reflect available
data as of 12/92 (57 F.R. 60913). Recalculated IRIS values for dibutyl phtha-
late are 2,700 ng/L for ingestion of contaminated water and organisms and
12,000 ng/L for ingestion of contaminated aquatic organisms only.
   Human health criteria were recalculated using IRIS to reflect available
data as  of 12/92 (57 F.R.  60890). Recalculated IRIS values for di-2-ethyl-
hexyl  phthalate are 1.8 ng/L for ingestion  of contaminated water and
organisms and 5.9 ng/L for ingestion of contaminated aquatic organisms
only. IRIS values are based on a 10"6 risk level for carcinogens.
   Human health criteria were recalculated using IRIS to reflect available
data as of 12/92 (57 F.R. 60913). Recalculated IRIS values  for dimethyl
phthalate are 313,000 ng/L for ingestion of contaminared water organisms
and 2,900,000 ng/L for ingestion of contaminated organisms only. IRIS val-
ues are based on a 10"6 risk level for carcinogens.
   Human health criteria were recalculated using IRIS to reflect available
data as of 12/92 (57 F.R. 60890). Recalculated IRIS values for butylbenzyl
phthalate are 3,000 ng/L for ingestion of contaminated water and organ-
isms and 5,200 ng/L for ingestion of contaminated organisms only. IRIS
values are based on a 10"6 risk level for carcingens.
                    (45 F.R. 79318, November 28,1980) (57 F.R. 60848, December 22,1992)
                    (60 F.R. 49602, September 26,1995)
                    See Appendix C for Human Health Methodology.
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196

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         POLYCHLORINATED  BIPHENYLS (PCBs)
                                  CAS# 1336-36-3
CRITERIA
Aquatic Life
Human Health
Not to exceed 2.0 jig/L in fresh water or 10.0 ng/L in salt water.
0.014 and 0.03 mg/L for freshwater and saltwater aquatic life, respec-
tively.

For polychlorinated biphenyls, the criterion to protect freshwater aquatic
life as derived using the guidelines  is 0.014 ng/L as a 24-hour average.
This concentration is probably too high because it is based on bioconcen-
tration factors measured in laboratory studies;  however, field studies
produce factors at least 10 times higher for fishes. The available data indi-
cate that acute toxicity to freshwater  aquatic life probably will occur only
at concentrations above 2.0 ng/L; therefore, the 24-hour average should
provide adequate protection against acute toxicity.
   The criterion to protect  saltwater aquatic life for polychlorinated
biphenyls as derived using the guidelines is 0.030 ng/L as a 24-hour aver-
age.  This concentration is probably too high because  it is based  on
bioconcentration factors measured in laboratory studies; however, field
studies produce factors at least 10 times  higher for fishes. The available
data indicate that acute toxicity to saltwater aquatic life probably will only
occur at concentrations above 10 ng/L; therefore, 24-hour average crite-
rion should provide adequate protection against acute toxicity.

For the maximum protection of human health from the potential carcino-
genic effects of exposure to polychlorinated biphenyls through ingestion
of contaminated water and contaminated aquatic organisms, the ambient
water concentration should be zero,  based on the nonthreshold assump-
tion for this chemical. However, zero level may not be attainable at the
present time.
   Published human health criteria were recalculated using Integrated
Risk Information System  (IRIS)  to  reflect available  data as of 12/92
(57 F.R. 60915). Recalculated IRIS values for PCBs 1016, 1221, 1232, 1242,
1248,1254, and 1260 are estimated at 10"6 risk level. The recommended cri-
teria for consumption of contaminated water and organisms is 0.000044
     and 0.000045 ng/L for organisms only.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60915, December 22,1992)
                   See Appendix B for Aquatic Life Methodology.
                   See Appendix C for Human Health Methodology.
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198

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                   POLYNUCLEAR AROMATIC
                          HYDROCARBONS
CRITERIA

Aquatic Life
Human Health
The limited freshwater database, available mostly from short-term biocon-
centration studies with two compounds, does not permit a statement
concerning acute or chronic toxicity for polynuclear aromatic hydrocar-
bons.
   The data that are  available indicate that acute toxicity to saltwater
aquatic life occurs at concentrations as low as 300 ng/L and would occur at
lower concentrations among species that are more sensitive than those
tested. No data are available concerning these hydrocarbons' chronic toxic-
ity to sensitive saltwater aquatic life.

For the maximum protection of human health from the potential carcino-
genic  effects of exposure to polynuclear aromatic hydrocarbons through
ingestion of contaminated water and contaminated aquatic organisms, the
ambient water concentration should be zero, based on the nonthreshold
assumption for this chemical. However, zero level may not be presently at-
tainable. Therefore, the levels that may result in incremental increase of
cancer risk over a lifetime are estimated at 10"5,10'6, and 10"7, with the cor-
responding recommended criteria 28.0 ng/L, 2.8 ng/L, and 0.28 ng/L,
respectively. If these estimates are made for consumption of aquatic organ-
isms only, excluding consumption of water, the levels are 311.0 ng/L, 31.1
ng/L, and 3.11 ng/L, respectively.
   Human health criteria for three polynuclear aromatic hydrocarbons —
acenaphylene, phenanthrene, and benzo (g,h,i) perylene — have been de-
leted (see 57 F.R. 60887, December 22, 1992). Although the water quality
criteria for these compounds have been deleted, information in the 1980
document may be useful.
                  (45 F.R. 79318, November 28,1980) (57 F.R. 60848, December 22,1992)
                  See Appendix C for Human Health Methodology.
                                                                            199

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200

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                                 SELENIUM
                                  CAS# 7782-49-2
CRITERIA
                   Not to exceed 20 ug/L in fresh water or 300 ng/L in salt water.
                   5.0 ug/L and 71 ^g/L for freshwater and saltwater aquatic life, respec-
                   tively.

Implementation  Because of the variety of forms of selenium in ambient water and the lack
                   of definitive information about their relative toxicities to aquatic species,
                   no available analytical measurement is known to be ideal for expressing
                   aquatic life criteria for selenium.  Previous aquatic life  criteria for metals
                   and metalloids were expressed in terms of the total recoverable measure-
                   ment, but newer criteria for metals and metalloids were expressed in terms
                   of the acid-soluble measurement. Acid-soluble  selenium — operationally
                   defined as the selenium that passes through a 0.45 um membrane filter af-
                   ter the sample has been acidified to a  pH between 1.5 and 2.0 with nitric
                   acid — is probably the best measurement at the  present time.

National Criteria  The procedures described in the "Guidelines for Deriving Numerical Na-
                   tional Water Quality Criteria for the Protection of Aquatic Organisms and
                   Their Uses" indicate that, except possibly where a locally important spe-
                   cies is very sensitive, freshwater aquatic organisms and their uses should
                   not be affected unacceptably if the four-day average concentration of sele-
                   nium does not exceed 5.0 ng/L more than once every three years on the
                   average,  and if the one-hour average concentration does not exceed 20
                   Hg/L more than once every three years on the average.
                      The procedures described in the "Guidelines for Deriving Numerical
                   National Water Quality Criteria for the Protection of Aquatic Organisms
                   and Their Uses" indicate that, except possibly  where a locally important
                   species is very sensitive, saltwater aquatic organisms and their uses should
                   not be affected unacceptably if the four-day average concentration of sele-
                   nium does not exceed 71  ng/L more than once every three years on the
                   average and if the one-hour average  concentration does not exceed 300
                   Hg/L more than once every three years on the average. If selenium is as
                   toxic to saltwater fishes as it is to freshwater fishes in the field, the status of
                   the fish community should be monitored whenever the concentration of
                   selenium exceeds 5 M-g/L in salt water.
Human Health
Human health criteria have been withdrawn for this compound (see 57
F.R. 60885, December 22, 1992). Although the human health criteria are
withdrawn, EPA published a document for this compound that may con-
tain  useful human health information. This document was  originally
noticed in 45 F.R. 79331, November 28,1980.
                    (45 F.R. 79331, November 28,1980) (53 F.R. 177, January 5,1988)
                    (57 F.R. 60911, December 22,1992)
                    See Appendix A for Aquatic Life Methodology.

                                                                                201

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202

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                                    SILVER
                                  CAS# 7440-22-4
CRITERIA
Aquatic Life
Human Health
Not to exceed 2.3 ng/L in salt water.
Freshwater values are hardness dependent. See text.
0.12 ng/L for freshwater aquatic life.

For freshwater aquatic life, the concentration (in ng/L) of total recoverable
silver should not exceed the numerical value given by
                        _(1.72[ln(hardness)]-6.52)
                        6
at any time. For example, at hardnesses of  50, 100, and  200  mg/L as
CaCOa, the concentration of total recoverable silver should not exceed 1.2,
4.1, and 13 ng/L, respectively, at any time. The available data indicate that
chronic toxicity to freshwater aquatic life may occur at concentrations as
low as 0.12 ng/L.
   For saltwater aquatic life, the concentration of total recoverable silver
should not exceed 2.3 ng/L at  any time. No data are available concerning
the chronic toxicity of silver to  sensitive saltwater aquatic life.

Human health  criteria have been withdrawn for this compound (see
57 F.R. 60885, December 22,1992). Although the human health criteria are
withdrawn, EPA published a document for this compound that  may con-
tain  useful  human  health information. This document was originally
noticed in 45 F.R. 79318, November 28,1980.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60911, December 22,1992)
                   See Appendix B for Aquatic Life Methodology.
                   See Appendix C for Human Health Methodology.
                                                                                 203

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204

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           SOLIDS  (SUSPENDED, SETTLEABLE)
                            AND TURBIDITY
CRITERIA
Freshwater Fish
and Other
Aquatic Life      Settleable and suspended solids should not reduce the depth of the com-
                   pensation point for photosynthetic activity by more than 10 percent from
                   the seasonally established norm for aquatic life.
Introduction
Rationale
The term "suspended and settleable solids" describes the organic and inor-
ganic particulate matter in water. The equivalent terminology used for
solids in "Standard Methods" is "total suspended matter" for suspended
solids, "settleable matter" for settleable solids, "volatile suspended mat-
ter" for volatile solids, and "fixed suspended matter" for fixed suspended
solids. The term "solids" is used in this  discussion because of its more
common use in the water pollution control literature.

Suspended solids and turbidity are important parameters in both munici-
pal and industrial water supply practices. Finished drinking waters have a
maximum limit of 1 turbidity unit where the water enters the distribution
system. This limit is based on health considerations as they relate to effec-
tive  chlorine  disinfection. Suspended  matter provides  areas where
microorganisms do not come into contact with the chlorine disinfectant.
The ability of  common water treatment processes (i.e., coagulation, sedi-
mentation, filtration, and  chlorination) to remove suspended matter to
achieve acceptable final turbidities is a function of the material's composi-
tion as well as its concentration. Because of the variability of such removal
efficiency, general raw water criterion for these uses cannot be delineated.
   Turbid water interferes with recreational use and aesthetic enjoyment
of water. It can be dangerous for swimming, especially if diving facilities
are provided, because of the possibility of  unseen submerged hazards and
the difficulty in locating swimmers in danger of drowning. The less turbid
the water, the more desirable it becomes  for swimming and other water
contact sports. Other  recreational pursuits,  such as boating and fishing,
will be adequately protected by suspended solids criteria developed for
protection of fish and other aquatic life.
   Fish and other aquatic life requirements concerning suspended solids
can be  divided into those whose effect occurs in the water column and
those whose effect occurs following sedimentation to the bottom of the
waterbody. Noted effects are similar for both fresh and marine waters.
   The effects of suspended solids on fish have been reviewed by the
European Inland Fisheries Advisory Commission. This 1965 review identi-
fied four effects on fish and fish food populations:

   1.   By acting directly on the fish swimming in water in which solids
       are suspended, and either killing them or reducing their growth
       rate, resistance to disease, etc.;
                                                           205

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                     2.  By preventing the successful development of fish eggs and larvae;

                     3.  By modifying natural movement and migrations of fish; and

                     4.  By reducing the abundance of food available to the fish.

                      Settieabie materials that blanket the bottom of waterbodies damage
                   the invertebrate populations, block gravel spawning beds, and, if organic,
                   remove dissolved oxygen from overlying waters. In a study downstream
                   from the discharge of a rock quarry where inert suspended solids were in-
                   creased to 80 mg/L, the density of macroinvertebrates decreased by 60
                   percent;  in areas of sediment accumulation, benthic invertebrate popula-
                   tions also decreased by 60 percent regardless of the suspended  solid
                   concentrations. Similar  effects have been reported downstream from an
                   area that was intensively logged. Major increases in stream suspended sol-
                   ids (25 ppm turbidity  upstream, versus 390 ppm downstream) caused
                   smothering of bottom invertebrates, reducing organism density to only 7.3
                   per square foot, versus 25.5 per square foot upstream.
                      When settleable solids block gravel spawning beds that contain eggs,
                   high mortalities result although evidence suggests that some species of
                   salmonids will not spawn in such areas.
                      Silt attached to the  eggs may prevent sufficient exchange of oxygen
                   and carbon dioxide between the egg and the overlying water. The impor-
                   tant variables are particle size, stream velocity, and degree of turbulence.
                      Deposition of organic materials to the bottom sediments can cause im-
                   balances in stream biota by increasing bottom animal density, principally
                   worm populations; diversity is reduced as pollution-sensitive forms disap-
                   pear. Algae likewise flourish in such nutrient-rich areas, although forms
                   may become less desirable.
                      Plankton and inorganic suspended materials reduce light penetration
                   into the waterbody, reducing the depth of the photic zone. This reduces
                   primary production and decreases fish food. In 1974 the National Acad-
                   emy of Sciences recommended that  the depth of light penetration not be
                   reduced by more than 10 percent. Additionally, the near surface waters are
                   heated because of the greater heat absorbency of the particulate material,
                   which tends to stabilize the water column and prevents vertical mixing.
                   Such mixing reductions decrease the dispersion of dissolved oxygen and
                   nutrients to lower portions  of the waterbody.
                      One partially offsetting benefit of suspended inorganic material in
                   water is the sorption of organic materials such as pesticides. Following this
                   sorption process, subsequent sedimentation may remove these materials
                   from the water column into the sediments.
                      Identifiable effects  of suspended solids'  on irrigation use of water in-
                   clude  the formation of crusts on top of the soil, which inhibit water
                   infiltration and plant emergence and impeded soil aeration; the formation
                   of films on plant leaves that blocks sunlight and impedes photosynthesis
                   and that may reduce the marketability of some leafy crops like lettuce; and
                   finally, the adverse effect on irrigation reservoir capacity, delivery canals,
                   and other distribution equipment.
                      The  criteria for freshwater fish  and other aquatic life are essentially
                   that proposed by the National Academy of Sciences and the Great Lake
                   Water Quality Board.


                   (Quality Criteria for Water, July  1976) PB-263943
                   See Appendix D for Methodology.
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               SULFIDE - HYDROGEN  SULFIDE
                                  CAS# 7783-06-4
CRITERIA
Introduction
Rationale
2 jig/L undissociated H2S for fish and other aquatic life in either fresh
water or salt water.

Hyrogen sulfide is a soluble, highly poisonous, gaseous compound that
smells like rotten eggs. Humans can detect it in air at a dilution of 0.002
ppm. It will dissolve in water at 4,000 mg/L at 20°C and one atmosphere
of pressure. Biologically, hydrogen sulfide is an active compound found
primarily as an anaerobic degradation product of both organic sulfur com-
pounds and inorganic sulfates. Sulfides are constituents of many industrial
wastes such as those from tanneries, paper mills, chemical plants, and gas
works. The anaerobic decomposition of sewage, sludge beds,  algae, and
other naturally deposited organic material is a major source of hydrogen
sulfide.
   When soluble sulfides are added to water, they  react with hydrogen
ions  to form HS" or H2S, the proportion of each depending on the pH. The
toxicity of sulfides derives primarily from H2S rather than from the hydro-
sulfide (HS") or sulfide (S=) ions.
   When hydrogen sulfide dissolves in water it dissociates according to
the following reactions:
        H2S~HS' + H+ and HS" <*>S"2 + H*
   At pH 9, about 99 percent of the sulfide is in the form of HS", at pH 7
the sulfide is equally divided between HS" and H2S; and at pH 5 about 99
percent of the sulfide is present as H2S. Investigators have minimized the
toxic effects of H2S on fish and other aquatic life because H2S is oxidized in
well-aerated water by natural biological systems to sulfates or is biologi-
cally oxidized to elemental sulfur.

The degree of hazard exhibited by sulfide to aquatic animal life is depend-
ent on the temperature, pH, and dissolved oxygen. AT lower pH values, a
greater proportion is in the form of the toxic undissociated H2S. In winter
when the pH is neutral or below or when dissolved oxygen levels are low
but not lethal to fish, the hazard from sulfides is exacerbated. Fish exhibit a
strong avoidance reaction to sulfide. Based on data from experiments with
the stickleback, if fish encounter a lethal concentration of sulfide, reason-
able  chance exists that they will be repelled by it before they are harmed.
This, of course, assumes that an escape route is open.
   Many past data on the toxicity of hydrogen sulfide to fish and other
aquatic life have been based on extremely short exposure periods. Conse-
quently, these early data  have indicated that concentrations between 0.3
and  0.4 mg/L permit fish to survive. Recent long-term data, both in field
situations and under controlled laboratory condition, demonstrate hydro-
gen sulfide toxicity at lower concentrations.
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                      Concentrations as high as 0.7 mg/L have been found within 20 mm of
                   the bottom of sludge beds, and  the levels of 0.1 to 0.02 mg/L were com-
                   mon within the first 20 mm of water above this layer. Walleye (Stizostedion
                   vitreum) eggs held in trays in this zone did not hatch. The hatchability of
                   northern pike (Esox lucius) eggs was substantially reduced at 25 ug/L at
                   H2S; at 47 ug/L, mortality was almost complete. Northern pike fry had 96-
                   hour LC50  values that varied from 17 to 32 ug/L at  normal oxygen levels
                   of 6.0 mg/L. The highest concentration of hydrogen sulfide that had no
                   observable  effect on eggs and fry was 14  and 4 ug/L, respectively. Eggs,
                   fry, and juveniles of walleyes and white suckers (Catostomus commersoni)
                   and safe levels in working on walleyes and fathead minnows (Pimephales
                   promelas) were found to vary from 2.9 ug/L to 12 ug/L, with eggs being the
                   least sensitive and juveniles being the most sensitive in short-term test. In
                   96-hour bioassays,  fathead minnows and goldfish (Carassius auratus) var-
                   ied greatly  in tolerance to hydrogen sulfide with changes in temperature.
                   They were  more tolerant at low temperatures (6 to 10°C). In addition, 1.0
                   mg/L  sulfide  caused 100 percent mortality in  72 hours with Pacific
                   salmon.
                      On the  basis of chronic tests evaluating growth and survival, the safe
                   H2S  level for bluegill (Lepomis  macrochirus) juveniles and adults was  2
                   fig/L. Egg  deposition in bluegills was reduced after 46 days in 1.4 ug/L
                   H2S. White sucker eggs were hatched at  15 ug/L, but juveniles showed
                   growth reductions at 1 ug/L. Safe level  for fathead minnows were be-
                   tween  2 and  3  ug/L. Studies  showed  that safe  levels for  Gammarus
                   Pseudolimnaeus and Hexagenia limbata were 2 and 15 ug/L, respectively.
                   Some species typical of normally  stressed habitats (Asellus  spp.) were
                   much more resistant.
                      Sulfide criteria for domestic or livestock use have not been established
                   because the unpleasant odor and taste would preclude such use at hazard-
                   ous concentrations.
                      The hazard from hydrogen sulfide to aquatic life is often localized  and
                   transient. Available data indicate that water containing concentrations of
                   2.0 ug/L undissociated H2S would not be hazardous to most fish and other
                   aquatic wildlife, but concentrations in excess of 2.0 ug/L would constitute
                   a long-term hazard.
                   (Quality Criteria for Water, July 1976) PB-263943
                   See Appendix D for Methodology.
208

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                      TAINTING  SUBSTANCES
CRITERIA

Aquatic Life


Rationale
Materials should not be present in concentrations that individually or in
combination produce undesirable flavors that are detectable by organolep-
tic tests performed on the edible portions of aquatic organisms.

Fish or shellfish with abnormal flavors, colors, tastes, or odors are either
not marketable or elicit consumer complaints and possible rejection of the
food source, even though subsequent lots of organisms may be acceptable.
In some areas, poor product quality can and has seriously affected or
eliminated the commercial fishing industry. Recreational fishing also  can
be affected  adversely by off-flavor fish. For the majority of sport fishers,
consuming the catch is part of their recreation; off-flavored catches can di-
vert the angler to  other waterbodies. This  can  have serious economic
impact on established recreation industries such  as tackle and bait sales
and boat and cottage rental.
    A number of wastewaters and chemical compounds have been found
to lower the palatability of fish flesh. Implicated wastewaters included
those from 2,4-D manufacturing plants, kraft and neutral  sulfite pulping
processes, municipal wastewater treatment plants, and slaughterhouses,
as well as oily, refinery, and phenolic wastes. The list of implicated chemi-
cal compounds is long; it  includes cresol  and phenol  compounds,
kerosene, naphthol, styrene, toluene, and exhaust outboard motor fuel.
    The susceptibility of fishes to the accumulation of tainting substances
is variable and depends on the species, length of exposure, and the pollut-
ant. As little as 0.1 ng/L o-chlorophenol can cause tainting of fish flesh. As
little as 5 ng/L of gasoline can impart off-flavors to fish.
                   (Quality Criteria for Water, July 1976) PB-263943
                   See Appendix D for Methodology.
                                                                               209

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210

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                             TEMPERATURE
CRITERIA
Freshwater
Aquatic Life      For any time of year, a location has two upper limiting temperatures
                   (based on the important sensitive species present at that time).

                      1.  One limit, a maximum temperature for short exposures, is time
                         dependent and given by the following species-specific equation:

                         Temperature (°C) = (1/b) [Logic [time (min)] -a) - 2°C
                         where:
                         Logic =  logarithm to base 10 (common logarithm)
                             a =  intercept on the "y" or logarithmic axis of the line fitted to
                                 experimental data, which is available for some species from
                                 Appendix II-C of the National Academy of Sciences (1974)
                             b =  slope of the line fitted to experimental data, available for
                                 some species from Appendix II-C of the National
                                 Academy of Sciences (1974)

                      2.  The second value is a limit on the weekly average temperature that

                         a. in cooler months — mid-October to mid-April in the North and
                            December to February in  the  South —  will protect against
                            mortality of important species if the elevated plume temperature
                            is suddenly dropped to the  ambient temperature, with the limit
                            being the acclimation temperature minus 2°C, when the lower
                            lethal  threshold  temperature  equals  the  ambient  water
                            temperature  (in  some regions this limitation  may also be
                            applicable in summer);
                         b. in the warmer months — April through October in the North and
                            March through  November in the South — is determined by
                            adding to the physiological optimum temperature (usually for
                            growth) a factor calculated as one-third of the difference between
                            the ultimate upper incipient lethal temperature and the optimum
                            temperature  for  the most sensitive important species (and
                            appropriate life state) that normally is found at that location and
                            time;
                         c. during reproductive seasons — generally April through June and
                            September through October in  the North and March through
                            May and October through November in the South — the limit is a
                            temperature that meets site-specific requirements for successful
                            migration, spawning, egg  incubation, fry rearing, and other
                            reproductive  functions  of important  species.  These  local
                            requirements should supersede all  other requirements when
                            they are applicable; or
                         d. is site-specific and  found necessary to preserve normal species
                            diversity or prevent appearance of nuisance organisms.

                                                                              211

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Marine
Aquatic Life
To assure protection of the characteristic indigenous marine community of
a waterbody segment from adverse thermal effects

   1.   The maximum acceptable increase in the weekly average
       temperature resulting from artificial sources is 10°C (1.8°F) during
       all seasons of the year, providing the summer maxima are not
       exceeded; and

   2.   Daily temperature cycles characteristic of the waterbody segment
       should not be altered in either amplitude or frequency.

    Summer thermal maxima, which define the upper thermal limits for the
communities of the discharge area, should be established on a site-specific
basis. Existing studies suggest the following regional limits as shown in Ta-
ble 1.

Table 1.—Regional Limits.

Sub-tropical regions (south of Cape Canaveral
and Tampa Bay. Fla.. and Hawaii)
Cape Hattcras. N.C.. to Cape Canaveral. Fla.
Lone Island (south shore) to Cape Hatteras.
N.C.
SHORT-TERM
MAXIMUM
32.2°C (90°F)
32.2°C <90°F)
30.6°C <87°F)
MAXIMLM
TRUE DAILY
MEAN
29.4T (8.vF)
29.4=C (8.T-F)
27.8'C (82=Fi
                     "True J.nl> inc;m - .n
                                     nl 24 hourK urmpcraiuri: rcuJmt>
Introduction
 Rationale
    Baseline thermal conditions should be measured at a site without un-
natural thermal  addition  from  any source,  which  is  in reasonable
proximity to the thermal discharge (within 5 miles), and which has similar
hydrography to that of the receiving waters at the discharge.

Human uses of water in and out of its natural situs in the environment are
affected by its temperature.  Offstream domestic uses and in-stream recrea-
tion  are   both   partially  temperature-dependent.  Likewise,   species
composition and activity of  life in any aquatic environment is regulated by
water  temperature. Since  essentially all  of these  are so-called "cold
blooded"  or poikilotherm organisms, the temperature of the water regu-
lates their metabolism and ability to survive and reproduce effectively.
Industrial uses for process water and cooling are likewise regulated by the
water temperature.
    Temperature,  therefore, is  an important  physical parameter that, to
some extent, regulates many of the beneficial uses of water. In 1967, the
Federal Water Pollution  Control Administration called temperature "a
catalyst, a depressant, an activator, a restrictor, a  stimulator, a controller, a
killer — one of the most important and most influential water quality char-
acteristics to life in water."

The suitability of water for total body immersion is greatly affected by tem-
perature.   In  temperate  climates,  dangers from  exposure  to  low
temperatures is more prevalent than exposure to elevated water tempera-
tures. Depending on the amount of activity by the swimmer, comfortable
temperatures range from 20°C to 30°C. Short durations of lower and higher
temperatures can be tolerated by most individuals. For example, for a 30-m-
inute period, temperatures of 10°C or 35°C can be tolerated without harm.
 212

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   Temperature also affects the self-purification phenomenon in water-
bodies,  and therefore, the aesthetic and sanitary qualities that exist.
Increased temperatures accelerate the biodegradation  of organic material
both in the overlying water  and in bottom deposits, which makes in-
creased demands on the dissolved oxygen resources  of a given system.
The typical situation is exacerbated by the fact that oxygen becomes less
soluble as water temperature increases. Thus, greater demands are exerted
on an increasingly scarce resource that may lead to total oxygen depletion
and obnoxious septic conditions.
   Indicator enteric bacteria, and presumably enteric pathogens, are like-
wise affected by temperature. Both  total  and fecal coliform bacteria die
away more rapidly in the environment with increasing  temperatures. Like-
wise, changes from a coldwater fishery to a warmwater fishery can occur
because temperature may be directly lethal to adults or fry and cause a re-
duction of activity or limit reproduction.
   Upper  and lower limits for temperature have been established for
many aquatic  organisms. Considerably more data exist for  upper than
lower limits. Tabulations of lethal temperatures for fish and other organ-
isms are available.  Factors  such  as diet, activity, age,  general  health,
osmotic stress, and even weather contribute to the lethality of temperature.
The  aquatic species, thermal  accumulation state, and  exposure time are
considered the critical factors.
   The effects of sublethal temperatures  on metabolism, respiration, be-
havior, distribution and migration, feeding rate, growth, and reproduction
have been summarized. Another study has illustrated that the tolerance
zone contains a more restrictive temperature range in which normal activ-
ity and growth occur; and an even more restrictive zone exists inside that
in which normal reproduction will occur.
   Data on the combined effects of increased temperature and toxic mate-
rials on fish indicate  that toxicity generally  increases  with increased
temperature an that organisms subjected to stress from toxic materials are
less tolerant of temperature extremes.
   An organisms tolerance to temperature extreme is a function of its ge-
neric ability to adapt to thermal changes.
   Temperature effects have been shown for water treatment processes.
Lower temperatures reduce the effectiveness of coagulation with alum and
subsequent  rapid sand filtration.  In one  study, difficulty was especially
pronounced below 5°C. Decreased temperature also decreases the effec-
tiveness of  chlorination. Based on  studies relating chlorine dosage  to
temperature, and with a 30-minute contact  time, dosages required for
equivalent  disinfective effect increased by as  much as a factor of 3 when
temperatures were decreased from 20°C  to 10°C. Increased temperature
may increase the water's odor because of  the increased volatility of odor-
causing compounds. Odor problems associated with plankton may also be
aggravated.
   The effects of temperature on aquatic organisms have been the subject
of comprehensive literature reviews and annual literature reviews publish-
ed by the Water Pollution Control Federation. Only highlights from the
thermal effects on aquatic life are presented here.
   Temperature changes in waterbodies can alter the existing aquatic
community. The dominance of various phytoplankton groups in specific
temperature ranges has been shown. For example, from 20°C to 25 C, dia-
toms predominated; green  algae predominated from  30°C to 35°C; and
blue-greens predominated above 35°C within  their characteristic tempera-

                                                              213

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                   ture range, the acclimation temperature prior to exposure, and the time of
                   exposure to the elevated temperature. The upper incipient lethal tempera-
                   ture or the highest temperature than 50 percent of a sample of organisms
                   can survive is determined on the organism at the highest sustainable accli-
                   mation temperature. The lowest temperature that 50 percent of the warm
                   acclimated organisms can survive in is the ultimate lower incipient lethal
                   temperature. True acclimation to changing temperatures requires several
                   days. The lower end of the temperature accommodation range for aquatic
                   life is 0°C in fresh water and somewhat less for saline waters. However, or-
                   ganisms acclimated to relatively warm water, when subjected to reduced
                   temperatures that under other conditions of acclimation would not be det-
                   rimental, may suffer a significant mortality caused by thermal shock.
                      Through the natural changes in climatic conditions, the temperatures
                   of waterbodies fluctuate daily, as well as seasonally. These changes do not
                   eliminate indigenous aquatic populations, but affect the existing commu-
                   nity  structure  and the  geographic  distribution  of  species.   Such
                   temperature changes are necessary to induce the reproductive cycles of
                   aquatic organisms and to regulate other life factors.
                      Artificially induced changes, such as the return of cooling water or the
                   release of cool hypolimnetic waters from impoundments, may alter indige-
                   nous aquatic ecosystems.  Entrained  organisms may  be damaged by
                   temperature increases across cooling water condensers if the increase is
                   sufficiently great or the exposure period sufficiently long. Impingement
                   upon condenser screens, chlorination for slime control, or other physical
                   insults damage aquatic life. However, data has shown  that algae passing
                   through condensers are not injured if the temperature of the outflowing
                   water does not exceed 345°C.
                      In open waters  elevated temperatures may affect periphyton, benthic
                   invertebrates, and fish, in addition to causing shifts in algae dominance.
                   Studies of the Delaware River downstream from a power plant concluded
                   that the periphyton population was considerably altered by the discharge.
                      The  number and distribution of bottom organisms decrease as water
                   temperature increase. The upper tolerance limit for a  balanced benthic
                   population structure is approximately 32°C. A large number of these inver-
                   tebrate species are able to tolerate higher temperatures than those required
                   for reproduction.
                      In order to define criteria for fresh waters, the following was cited as
                   currently defineable requirements:

                      1.   Maximum sustained temperatures that are consistent with
                          maintaining desirable levels of productivity;

                      2.   Maximum levels of metabolic acclimation to warm temperatures
                          that will permit return to ambient winter temperatures should
                          artificial sources of heat cease;

                      3.   Time-dependent temperature limitations for survival of brief
                          exposures to temperature extremes, both upper and lower;

                      4.   Restricted temperature ranges for various states of reproduction,
                          including (for fish) gametogenesis, spawning migration, release of
                          gametes, development of the embryo, commencement of
                          independent feeding (and other activities) by juveniles, and
                          temperatures required for metamorphosis, emergence, or other
                          activities of lower forms;
214

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   5.  Thermal limits for diverse species compositions of aquatic
       communities, particularly where reduction in diversity creates
       nuisance growths of certain organisms, or where important food
       sources (food chains) are altered;

   6.  Thermal requirements of downstream aquatic life (in rivers) where
       upstream diminution of a coldwater resource will adversely affect
       downstream temperature requirements.

   The major portion of such information that is available, however, is for
freshwater fish species rather than lower forms of marine aquatic life.
   The temperature-time duration for short-time exposures, such that 50
percent of a given population will survive and  extreme temperature, fre-
quently is expressed mathematically by fitting  experimental data with a
straight line on a semi-logarithmic plot with time on the logarithmic scale
and temperature on the linear scale. In equation  form, this  50 percent mor-
tality relationship is
       Logio (time(minutes} = a + b (Temperature  (°Q)
       where:
       Logio = logarithm to base 10 (common logarithm)
           a = intercept on the "y" or logarithmic axis of the line fitted to
              experimental data and which is available for some species
              from Appendix II-C of the National Academy of Sciences
              document
           b  = slope of the line fitted to experimental data and which is
              available for some species from Appendix II-C of the
              National Academy of Sciences document

   To  provide a safety factor so that none or only a few organisms will
perish, experiments found that a criterion of 2°C below  maximum tem-
perature is usually sufficient. To provide safety for all the organisms,  the
temperature causing a median mortality for 50  percent of the  population
would be calculated and reduced by 2°C in the case of an elevated tem-
perature.  Available scientific  information includes upper  and  lower
incipient lethal temperatures, coefficients  "a"  and "b" for the  thermal re-
sistance equation, and  information of size,  life stage,  and  geographic
source of the particular test species.
   Maximum temperatures for an extensive exposure (e.g., more than one
week)  must be divided into  those for warmer periods and winter. Other
than for reproduction, the most temperature-sensitive life function ap-
pears to be growth. A satisfactory estimate of a limiting maximum weekly
mean temperature may be an average of the optimum temperature  for
growth and the temperature for zero net growth.
   Because of the difficulty in determining the temperature  of zero  net
growth, essentially the same temperature can be derived by adding to  the
optimum essentially to temperature (for growth or other physiological
functions) a factor calculated as one-third of the  difference between the ul-
timate upper  incipient lethal temperature and the optimum temperature.
In equation form

  Maximum weekly    =   optimum    +   1/3 (ultimate upper incipient lethal
 average temperature     temperature         temperature - optimum
                                            temperature)
    Since temperature tolerance varies with various states of development
of a  particular species, the criterion for a particular location would be cal-
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                   culated for the most important life form likely to be present during a par-
                   ticular  month.  One  caveat  in  using the  maximum  weekly  mean
                   temperature is that the limit for  short-term  exposure must not be ex-
                   ceeded.  Example  calculations for predicting the summer maximum
                   temperatures for short-term survival and for extensive exposure for vari-
                   ous fish species are presented in Table 2. These calculations use the above
                   equations and data from EPA's Environmental Research Laboratory in Du-
                   luth.

                    Table 2.— Example calculated values for maximum weekly average temperatures for
                    growth and short-term maxima for survival for juveniles and adults during the
                    summer (centigrade and Fahrenheit).
SPECIES
Atlantic salmon 	
Bigmouth buffalo 	
Black crappic
Blucaill 	
Brook trout 	
Cam 	
Channel catfish 	
Coho salmon
Emerald shiner 	
Freshwater drum 	
Lake herrin° (Cisco)
Largemouth bass 	
Northern pike 	
Rainbow trout
Sauocr 	
Smallmouth bass 	
Smallmouth buffalo 	
Soekevc salmon
Striped bass 	
Threudfin shad
White bass
White crappic
White sucker 	
Yellow perch

GROWTH'
20 (68)
27 (81)
32 (90)
19 (66)

32 (90)
18 (64)
30 (86)

17 (63 r
32 (90)
28 (82)
19 (66)
25 (77)
29 (84)
18 (64)


28 (82)
28 (82r
">9 (84)

MAXIMA"
23 (73)

15 (95)
24 (75)

35(95)
24 (75)


25 (77)
34(93)
30 (86)
"•4 (75)


i"1 (72)



—

                      'Calculated aeeordmi: to the equation lu^ini; optimum temperature lor i:rouihi maximum weekK average temperature
                    loi 'jrouth - optimum temperature - ' • (ultimate incipient lethal temperature - optimum teniper:iturei.
                      "Ba*ed on temperature I O = 1 h |loi:,,.uime in minute*! - a| - 2 C. aeclimalion ut the maximum ueekl)
                    .ner.i'jc temperature lor MJ miner Drouth, and Jala in Appendix II-C ol "\\ jier Quail I) Criteria, published b\ National
                    •Wadeim ol Science-
                      •Ba-ed on data lor lanae iKKI.-Uululh. I1"<>i
                       The winter maximum temperature must not exceed the ambient water
                    temperature by more than the amount of change a specimen acclimated to
                    the plume temperature can tolerate. Such a change could occur by a cessa-
                    tion of the source of heat or by the specimen being driven from an area by
                    addition of biocides or other factors. However, data is inadequate to esti-
                    mate a safety factor for the "no stress" level from cold shocks.
                       Reviews have been performed on the effects of temperature on aquatic
                    life reproduction and development. Reproductive events are noted as per-
                    haps the most thermally restricted of all life phases, assuming other factors
                    are at  or near optimum levels. Natural short-term temperature fluctua-
                    tions appear to cause reduced reproduction of fish and invertebrates.
                       Inadequate data are available to quantitate the most temperature-sen-
                    sitive life stages  among various aquatic species. Uniform elevation of
                    temperature a few degrees but still within the spawning range may lead to
                    advanced spawning  for spring  spawning species  and  delays for  fall
                    spawners. such changes may not be detrimental unless asynchrony occurs
                    between newly hatched juveniles and their normal food source. Such asyn-
                    chrony may  be most pronounced  among anadromous species or other
                    migrants who pass from the warmed area to  normally chilled, unproduc-
216

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Table 3.— Summary of reported values for maximum weekly average temperatures
for spawning and short-term maxima for embryo survival during the spawning
season (centigrade and Fahrenheit).
SPECIES
Atlantic salmon 	
Biemouth buffalo
Black crappie 	
Bluetiill
Brook trout . . .
Cam 	
Channel catfish 	
Coho salmon
Emerald shiner
Freshwater drum
Lake herring (Cisco) 	
Lareemouth bass 	
Northern pike .
Rainbow trout 	
Sauecr 	
Smallmouth bass 	
Smallmouth buffalo
Sockcve salmon
Striped bass 	
Thrcadfin shad
White bass
White crappie . ...
White sucker
Yellow perch

SPAWNING
5 (4||
17 (63)
17 (6^)
25 (77)
9 (48)
21 (70)
27 (81)
10 (50)
24 (75)
21 (70)
3 (37)
21 (70)
11 (5"1)
8 (46)
12 (54)
17 (63)
21 (70)
10 (50)
18 (64)
18 (64)
17 (63)
18 (64)
10 (50)
P 

EMBKVO
SURVIVAL
1 1 (S2>
"•7 (XI )•
"•(> (6X1-
34 (9 3 >
1 3 1 ^ I
3> (91 )
"•9 iX4i-
1 ^ n*i-
""8 lSV
""6 ( 79 >
X i46i
"•7 (XI r
19 (Wii
15 (59 >
IX (Mi
2> I?M-
"•X (X"1!-
1 i i ^ i
24 (7S)
34 (93)
"•6 (79|
""3 (73)
"HI (6X)
"•() 16X1

  JThe optimum or mean ot the rani:e nl *pawnmi: temperatures reported lor the specie-- il-.RL-l);!hi:!i. |')~M
  "The upper temperature lor successful incubation and hatching reported lor the species iLRI.-Duluth, lii~ii>
  'I ppt:r lemperalure lor spauntni:

tive  area. Reported temperature data on maximum  temperatures for
spawning and embryo survival have been summarized in Table 3.
    Although the limiting effects of thermal addition to estuarine and ma-
rine waters are not as conspicuous in the fall, winter, and spring as during
the summer season of maximum heat stress, nonetheless crucial thermal
limitations do exist. Hence, thermal additions to the  receiving waters must
be minimized during all seasons. Size of harvestable stocks of commercial
fish and shellfish, particularly near geographic limits of the fishery, appear
to be markedly influenced by slight changes in the long-term temperature
regime.
    Studies on the relationship between temperature and annual variation
in seven-year catch data for winter flounder  (Pseudopleuronected ameri-
canus) in Narragansett Bay, Rhode Island,  revealed that  a  78 percent
decrease in annual catch correlated closely with a 0.5°C increase in the av-
erage temperature over the 30-month period  between  spawning and
recruitment in to the fishery. Sissenwine's 1874 model predicts a 68 percent
reduction of recruitment in yellowtail flounder (Limanda ferruginea) with a
1°C long-term elevation in southern New England waters.
    Community  balance can be influenced strongly  by such  temperature-
dependent  factors as rates of reproduction, recruitment, and growth of
each component population. A few degrees elevation in average monthly
temperature can appreciably alter a community through changes in inter-
species relationships. A 50 percent reduction in the softshell clam fishery in
Maine by the  green  crab (Carcinus maenus) illustrates how an increase in
winter temperatures can establish new predator-prey relationships. Over a
period of four years, temperature naturally ameliorated and the monthly
mean for the coldest month of  each year did not fall below  2°C. This ap-
parently precluded appreciable ice formation and winter cold kill of the
green crab and permitted a major expansion of its population, with result-
ing increased predation of the softshell clam.
                                                                217

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                      Temperature is a primary factor controlling reproduction and can in-
                  fluence many events of the reproductive  cycle from gametogenesis to
                  spawning. Among marine invertebrates, initiation of reproduction (game-
                  togenesis) is often triggered  during late  winter  by attainment of a
                  minimum environmental threshold temperature. In some species, avail-
                  ability of adequate food is also a requisite. Elevated temperature can limit
                  gametogenesis by preventing accumulation of nutrients in  the gonads.
                  This problem could be acute during the winter if food availability and
                  feeding activity  is reduced. Most marine organisms  spawn during the
                  spring and summer; gametogenesis is usually initiated during the pre-
                  vious fall. Some species spawn only during the fall (herring), while others
                  spawn during the winter and early spring. At the higher latitudes, winter
                  breeders include such estuarine community dominants as acorn barnacles
                  (Balanus balanus and 5. balanoides), the edible blue mussel (Mytilus edulis),
                  sea urchin Strongylocentrotus drobachiensis), sculpin, and the winter floun-
                  der  (Pseudopleuronectes americanus). The two  boreal barnacles  require
                  temperatures below 10°C before egg production will be initiated. Adapta-
                  tions for reproduction exist that are dependent on temperature condition
                  closes to the natural cycle.
                      Juvenile and adult fish  usually thermoregulate behaviorally by mov-
                  ing to water having temperatures closest to their thermal preference. This
                  provides a thermal environment that approximates the optimal tempera-
                  ture  for  many  physiological  functions,  including  growth.   As  a
                  consequence, fishes usually are attracted to heated water during the fall,
                  winter, and spring. Avoidance will occur as warmer temperature exceeds
                  the preferendum by  1 to 3°C. This response precludes problems of heat
                  stress for juvenile and adult fishes during the summer, but several poten-
                  tial problems exist during the other seasons. The possibility of cold shock
                  and death of plume-entrained fish resulting from winter plant shutdown
                  is well recognized. Also, increased incidence of disease and a deterioration
                  of physiological condition  has been observed among plume-entrained
                  fishes, perhaps because of insufficient  food. A weight  loss  of approxi-
                  mately 10 percent  for each 1°C rise in water temperature  has been
                  observed in fish when food is absent. Indirect adverse effects may also oc-
                  cur on the indigenous community because of increased predation pressure
                  if thermal addition leads to a concentration of fish that are dependent on
                  this community for their food.
                      Fish migration is often  linked to natural environmental temperature
                  cycles. In early spring, fish employ temperature as their environmental cue
                  to migrate northward (e.g.,  menhaden, bluefish) or to move inshore (win-
                  ter flounder). Likewise, water temperature strongly influences timing of
                  spawning runs of anadromous fish into rivers. In the autumn,  a number of
                  juvenile marine fishes and shrimp are dependent on a drop in temperature
                  to trigger their migration from estuarine nursery grounds for oceanic dis-
                  persal or southward migration.
                      Thermal discharges should not alter diurnal and tidal temperature
                  variations normally experienced by marine communities. Laboratory stud-
                  ies show thermal tolerance  to be enhanced when animals are maintained
                  under a diurnally fluctuating temperature regime rather than at a constant
                  temperature. A daily cyclic regime can be protective additionally as it re-
                  duces duration of exposure  to extreme temperatures.
                      Summer thermal maxima should be  established to protect the various
                  marine communities within each biogeographic region. During the sum-
                  mer, naturally elevated temperatures may  be  of sufficient magnitude to
                  cause  death or emigration. This more commonly occurs in tropical and

218

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warm temperate zone waters, but has been reported for enclosed bays and
shallow waters in other regions as well. Summer heat stress also can con-
tribute to increased incidence of disease or parasitism; reduced or blocked
sexual maturation; inhibited or blocked embryonic cleavage of larval de-
velopment; reduced feeding and growth of juveniles and adults; increased
predation; and reduced productivity of macroalgae and seagrasses.  The
general ceilings set forth here are derived from studies delineating limiting
temperatures for the more thermally sensitive species or communities of a
biogeographic region.
(Quality Criteria for Water, July 1976) PB-263943
See Appendix D for Methodology.
                                                              219

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220

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      2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN
                            (TCDD)  (DIOXIN)
CRITERIA

Aquatic Life
Human Health
Not enough data are available concerning the effects of 2,3,7,8-TCDD on
aquatic life and its uses to derive national criteria. The available informa-
tion indicates that acute values for some freshwater animal species are 1.0
Hg/L; some chronic values are < 0.01 ng/L; and the chronic value for rain-
bow trout (Oncorhynchus mykiss) is 0.001 ng/L. Because exposures of.some
species of fishes to 0.01 ng/L for < 6 days resulted in substantial mortality
several weeks later, derivation of aquatic life criteria for 2,3,7,8-TCDD may
require special consideration.
   Predicted bioconcentration factors (BCFs) for 2,3,7,8-TCDD range from
3,000 to 900,000, but the available measured BCFs range from 390 to 13,000.
If the BCF is 5,000, concentrations 0.00001 ng/L should result in concentra-
tions in edible freshwater and saltwater fish  and shellfish that  exceed
levels identified in a Food and Drug Administration health advisory. If the
BCF is 5,000 or if uptake in a field situation is greater than in laboratory
tests, the value of 0.00001 ng/L will be too high.

For the maximum protection of human health from the potential carcino-
genic effects of 2,3,7,8-TCDD exposure through ingestion of contaminated
water and contaminated aquatic organisms, the ambient water concentra-
tion  should  be zero.  This  criterion  is based on the nonthreshold
assumption for 2,3,7,8-TCDD. However, zero may  not be an attainable
level at this time. Therefore, the levels that may result in an increase of can-
cer risk over the lifetime are  estimated at  10"5,  10"6, and 10"7, and the
                                           7             fi
corresponding recommended criteria are 1.3 x 10" ng/L, 1.3 x 10"  ng/L,
and 1.3 x 10"9 ng/L, respectively.
   If the above estimates are made for consumption of aquatic organisms
only, excluding consumption of water, the levels are 1.4 x 10"  ng/L, 1.4 x
10  ng/L, and 1.4 x 10'9 ng/L, respectively. If these estimates are made for
comsumption of water only, the levels are 2.2 x 10" fig/L, 2.2 x 10" ng/L,
and 2.2 x 10"8 Kg/L./ respectively.
                   (49 F.R. 5831, February 15,1984)
                   See Appendix A for Aquatic Life Methodology.
                                                                             221

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222

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                   TETRACHLOROETHYLENE
                                 CAS# 127-18-4
CRITERIA

Aquatic Life
Human Health
For freshwater aquatic life, the available data for tetrachloroethylene indi-
cate that acute and chronic toxicity occurs at concentrations as low as 5,280
and 840 ng/L, respectively, and would occur at lower concentrations
among species that are more sensitive than those tested.
   For saltwater aquatic life, the available data for tetrachloroethylene in-
dicate that acute and chronic toxicity occurs at concentrations as low as
10,200 and 450 ng/L, respectively, and would occur at lower concentra-
tions among species that are more sensitive than those tested.

For the maximum protection of human health from the potential carcino-
genic  effects of exposure to tetrachloroethylene through ingestion of
contaminated water and  contaminated aquatic organisms, the  ambient
water concentrations should be  zero, based on the nonthreshold assump-
tion  for this chemical. However, zero level  may  not  be  attainable.
Therefore, the levels that may result in incremental increase of cancer  risk
over the lifetime are estimated  at 10, 10" , and 10" .  The corresponding
recommended criteria are 8.0 ng/L, 0.80 ^g/L, and 0.08 ng/L, respectively.
If these estimates are made for consumption of aquatic organisms only, ex-
cluding consumption of water,  the levels are 88.5 ng/L, 8.85 ng/L,  and
0.88 |xg/L, respectively.
                   (45 F.R. 79318, November 28,1980)
                   See Appendix C for Human Health Methodology.
                                                                             223

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224

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                                  THALLIUM
                                  CAS# 7440-28-0
CRITERIA

Aquatic Life
Human Health
For freshwater aquatic life, the available data for thallium indicate that
acute and chronic toxicity occurs at concentrations as low as 1,400 and 40
Hg/L, respectively, and would occur at lower concentrations among spe-
cies that are more sensitive than those tested. Toxicity to one species of fish
occurs at concentrations as low as 20 ng/L after 2,600 hours of exposure.
   For saltwater aquatic life, the available data for thallium indicate that
acute toxicity occurs at concentrations as low as 2,130 ng/L and would oc-
cur at lower concentrations among species that are more sensitive than
those tested. No data are available concerning the chronic toxicity of thal-
lium to sensitive saltwater aquatic life.

Human health criteria were recalculated using Integrated Risk Informa-
tion  System (IRIS)  to reflect available  data as of 12/92 (57 F.R. 60848).
Recalculated IRIS values for thallium are 1.7 ug/L for ingestion of con-
taminated  water  and  organisms and  6.3  ng/L  for  ingestion  of
contaminated aquatic organisms only.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60848, December 22,1992)
                   See Appendix C for Human Health Methodology.
                                                                                 225

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226

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                                  TOLUENE
                                   CAS# 108-88-3
CRITERIA

Aquatic Life
Human Health
The available data for toluene indicate that acute toxicity to freshwater
aquatic life occurs at concentrations as low as 17,500 ng/L and would oc-
cur at lower concentrations among species that are more sensitive than
those tested. No data are available concerning the chronic toxicity of tolu-
ene to sensitive freshwater aquatic life.
   The available data for toluene indicate that acute and chronic toxicity
to saltwater aquatic life occurs at concentrations as low as 6,300 and 5,000
ug/L, respectively, and would occur at lower concentrations among  spe-
cies that are more sensitive than those tested.

Human  health criteria were recalculated using Integrated Risk Informa-
tion System  (IRIS) to reflect available data as  of 12/92  (57 F.R. 60848).
Recalculated IRIS values for toluene are 6,800 \ig/L for ingestion of  con-
taminated water  and organisms  and 200,000 ^g/L for ingestion of
contaminated organisms only.
                   (45 F.R. 79318, November 28,1980) (57 F.R. 60848, December 22,1992)
                   See Appendix C for Human Health Methodology.
                                                                                227

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228

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                                TOXAPHENE
                                   CAS# 8001-35-2
CRITERIA

Aquatic Life
Summary
4-day average of 0.0002 ng/L
1-hour average of 0.73 ng/L
4-day average of 0.0002 ng/ L
1-hour average of 0.21
Freshwater

Saltwater —
The acute sensitivities of 36 freshwater species in 28 genera ranged from
0.8 ng/L to 500 ng/L. Such important fish species as the channel catfish,
largemouth bass, chinook and coho salmon, brook, brown, and rainbow
trout, striped bass, and bluegill had acute sensitivities ranging from 0.8
Hg/L to 10.8 |ig/L. Chronic values for four freshwater species range from
less than 0.039 ng/L for the  brook trout (Salvelinus fontinalis) to 0.1964
Hg/L for the channel catfish (Ictalurus punctatus).
   The growth of algae was affected at 100 to 1,000 ng/L, and bioconcen-
tration  factors from  laboratory  tests  ranged  from 3,100  to 90,000.
Concentrations in lake trout in the Great Lakes have frequently exceeded
the Food and Drug Administration (FDA) action level of 5 mg/kg, even
though the concentrations in the water seem to be only 1 to 4 ng/L. These
concentrations in lake water are thought  to have  resulted from toxaphene
being transported to the Great Lakes from remote sites, the locations of
which are not well known.
   The acute toxicity of toxaphene to  15 species of saltwater animals
ranges from 0.53 for pinfish (Lagodon  rhomoides) to 460,000 ng/L for the
adults  of the clam (Rangia cuneata). Except for resistant species tested at
concentrations greater than toxaphene's water solubility, acute values for
most species were within a factor  of 10. The toxicity of toxaphene was
found  to decrease slightly with increasing salinity for  adult blue  crabs
(Callinectes sapidus), whereas no  relationship between toxicity and salinity
was observed with the threespine stickleback (Gasterosteus aculeatus). Tem-
perature significantly affected the toxicity of toxaphene to blue crabs.
   Early life-stage toxicity tests- have been conducted with the sheepshead
minnow (Cyprinodon  variegatus) and the longnose  killifish (Fundulus
similis), whereas life-cycle tests have been conducted with the sheepshead
minnow and a mysid. For the sheepshead minnow, chronic values of 1.658
Hg/L from the early life-stage test and 0.7141 ng/L from the life-cycle tox-
icity test are similar to the 96-hour LC50 of 1.1  ng/L. Killifish are more
chronically sensitive, with effects noted at 0.3 ng/L. In the life-cycle test
with the mysid, no adverse effects were observed at the highest concentra-
tion tested, which was only slightly below the 96-hour LC50, resulting in
an acute-chronic ratio of 1.132.
   Toxaphene is bioconcentrated by an oyster,  Crassostrea  virginica, and
two fishes, C. variegatus and F.  similis, to concentrations that  range from
9,380 to 70,140 times that in the test solution.
                                                                                  229

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National Criteria The procedures described in the "Guidelines for Deriving Numerical Na-
                   tional Water Quality Criteria for the Protection of Aquatic Organisms and
                   Their Uses" indicate that, except possibly where a locally important spe-
                   cies is very sensitive, freshwater aquatic organisms and their uses should
                   not be  affected  unacceptably if the four-day  average concentration of
                   toxaphene does not exceed Q.QQQ2 }ig/L more than once every three years
                   on the average and if the one-hour average concentration does not exceed
                   0.73 ng/L more than once every three years on the average. If the concen-
                   tration  of toxaphene  does exceed  0.0002 ng/L, the edible portions of
                   consumed species should be analyzed to  determine whether the concen-
                   tration  of toxaphene  exceeds the FDA action level of 5 mg/kg. If the
                   channel catfish is as acutely sensitive as some data indicate it might be, it
                   will not be protected by this criterion.
                       The procedures described in the guidelines indicate that, except possi-
                   bly where a locally important species is very sensitive, saltwater aquatic
                   organisms and their uses should not be affected unacceptably if the four-
                   day average concentration of toxaphene does not exceed 0.0002 ng/L more
                   than once every three years on the average  and if the one-hour average
                   concentration does not exceed 0.21 ng/L more than once every three years
                   on the average. If the concentration of toxaphene does exceed 0.0002 ng/L,
                   the edible portions of  consumed species should be analyzed to determine
                   whether the concentration of toxaphene exceeds the FDA action level of 5
                   mg/kg.
                       In the EPA's  best scientific judgment,  three years is the average
                   amount of time aquatic ecosystems should be provided between excur-
                   sions. The resiliences of ecosystems and their abilities to  recover  differ
                   greatly, however, and site-specific allowed excursion frequencies may be
                   established if adequate justification is provided.
                       Criteria for developing water quality-based permit limits and for de-
                   signing waste treatment facilities  must  be applied to an appropriate
                   wasteload allocation model; dynamic models are preferred. Limited data
                   or other considerations might make their use impractical; in which case,
                   rely on  a steady-state model.
Human Health
Human health criteria were recalculated using Integrated Risk Informa-
tion System (IRIS) to reflect available data as of 12/92 (57 F.R. 60848).
Recalculated IRIS values for toxaphene are 0.00073 M-g/L for ingestion of
contaminated water and organisms and 0.00075 ng/L for ingestion of con-
taminated organisms only.
                    (51 F.R. 43665, December 3,1986) (57 F.R. 60848, December 22,1992)
                    See Appendix A for Aquatic Life Methodology.
 230

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                      TRICHLOROETHYLENE
                                   CAS# 79-01-6
CRITERIA

Aquatic Life
Human Health
The available data for trichloroethylene indicate that acute toxicity to
freshwater aquatic life occurs at concentrations as low as 45,000 ng/L and
would occur at lower concentrations among species that are more sensitive
than those tested. No data are available concerning the chronic toxicity of
trichloroethylene to sensitive freshwater aquatic life, but the behavior of
one species is adversely affected at concentrations as low as 21,900 ng/L.
   The available data for trichloroethylene indicate that acute toxicity to
saltwater aquatic life occurs at concentrations as low as 2,000 ug/L and
would occur at lower concentrations among species that are more sensitive
than those tested. No data are available concerning the chronic toxicity of
trichloroethylene to sensitive saltwater aquatic life.

For the maximum  protection of human health from the potential carcino-
genic  effects  of exposure to trichloroethylene  through  ingestion of
contaminated water and contaminated aquatic organisms, the ambient
water concentration should be zero, based on the nonthreshold assump-
tion for this chemical. However,  zero level may  not be attainable at the
present time. Therefore, the levels that may result in incremental increase
of cancer risk over the lifetime are estimated at 10"5,10'6, and 10"7. The cor-
responding recommended criteria are 27 ^g/L, 2.7 ug/L, and 0.27 ng/L,
respectively. If these estimates are made for consumption of aquatic organ-
isms only, excluding consumption of water, the levels are 807 ng/L, 80.7
    , and 8.07 ug/L, respectively.
                   (45 F.R. 79318, November 28,1980)
                   See Appendix C for Human Health Methodology.
                                                                               231

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232

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                          VINYL CHLORIDE
                                  CAS# 75-01-4
CRITERIA

Aquatic Life


Human Health
No freshwater or saltwater organisms have been tested with vinyl chlo-
ride; therefore, no statement can be  made concerning acute  or chronic
toxicity.

For the maximum protection of human health from the potential carcino-
genic effects  of exposure to  vinyl  chloride  through  ingestion  of
contaminated  water and contaminated aquatic organisms, the ambient
water concentrations should be zero, based on the nonthreshold assump-
tion for this chemical. However, zero level may not be attainable at the
present time. Therefore, the levels that may result in incremental increase
of cancer risk over the lifetime are estimated at 10" , 10" , and 10" . The cor-
responding recommended criteria are 20 ng/L, 2.0 tig/L, and 0.2 ng/L,
respectively. If these estimates are made for consumption of aquatic organ-
isms only, excluding consumption of water, the levels are 5,246 ng/L, 525
Hg/L, and 52.5 ng/L, respectively.
                   (45 F.R. 79318, November 28,1980)
                   See Appendix C for Human Health Methodology.
                                                                             233

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234

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                                       ZINC
                                   CAS# 7440-66-6
CRITERIA	

Aquatic Life       Saltwater —   4-day average of 86 ug/L
                                  1-hour average of 95 ng/L
                    Freshwater criteria are hardness dependent. See text.

Summary         Acute toxicity values available for 43 species of freshwater animals and
                    data for eight species indicate that acute toxicity decreases as hardness in-
                    creases. When adjusted to a hardness of 50 mg/L, sensitivities range from
                    50.70 ng/L for Ceriodaphnia reticulata to 88,960 ug/L for a damselfly. Addi-
                    tional data indicate that toxicity increases as temperature increases.
                        Chronic toxicity data are available for nine freshwater species. Chronic
                    values for two invertebrates ranged from 46.73 ug/L for Daphnia magna to
                    5,243  ug/L for the caddisfly (Clistoronia magnificia). Chronic values for
                    seven fish species ranged from 36.41 ug/L for the flagfish (Jordanella flori-
                    dae) to 854.7 ug/L for the brook trout (Salvelinus fontinalis). Acute-chronic
                    ratios ranged from 0.2614 to 41.20, but  the ratios for the sensitive species
                    were all less than 7.3.
                        The sensitivity range of freshwater plants to zinc is greater than that
                    for animals. Growth of the alga (Selenastrum capriocornutum) was inhibited
                    by 30 ug/L. On the other hand, with several  other species of green algae,
                    four-day ECSOs exceeded 200,000 ng/L. Zinc  was found to bioaccumulate
                    in freshwater animal tissues from 51 to 1,130 times the concentration pre-
                    sent in the water.
                        Acceptable acute toxicity values for zinc are available for 33 species of
                    saltwater animals including 26 invertebrates and 7 fish.  LCSOs range from
                    191.5  ug/L for cabezon (Scorpanichthys marmoratus) to 320,400 ug/L for
                    adults of another clam, Macoma balthica.  Early  life stages of saltwater inver-
                    tebrates and fishes are generally more sensitive to zinc than juveniles and
                    adults. Temperature has variable and inconsistent effects on the sensitivity
                    of saltwater invertebrates to zinc. The  sensitivity of saltwater vertebrate
                    animals to zinc decreases with increasing salinity, but the magnitude of the
                    effect is species-specific.
                        A life-cycle test with the mysid (Mysidopsia bahia) found unacceptable
                    effects at 120 ug/L but not at 231 ug/L, and the acute-chronic ratio was
                    2.997. Seven  species of saltwater  plants were affected at concentrations
                    ranging from 19 to 10,100 ug/L. Bioaccumulation data  for zinc are avail-
                    able for seven species of saltwater algae and  five species of saltwater
                    animals. Steady-state zinc bioconcentration factors for the 12 species range
                    from 3.692 to 23,820.

 National  Criteria  The procedures described in the "Guidelines for Deriving Numerical Na-
                    tional Water Quality Criteria for the Protection of Aquatic Organisms and
                    Their Uses" indicate that, except possibly where a locally important  spe-

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                   cies is very sensitive, freshwater aquatic organisms and their uses should
                   not be affected unacceptably if the four-day average concentration of zinc
                   (in ug/L) does not exceed the numerical value given by
                                         _(0.8473[ln(hardness)]+0.7614)
                                         "
                   more than once every three years on  the average and if the one-hour
                   average concentration (in ^g/L)  does  not exceed the numerical value
                   given by
                                         _(0.8473[ln(hardness)]+0.8604)
                                         G
                   more  than once every three years on  the average.  For example,  at
                   hardnesses of 50, 100, and  200 mg/L  as CaCO^ the four-day average
                   concentrations of zinc are 59, 110 and 190  ng/L, respectively, and the
                   one-hour average concentrations are 65, 120, and 210 ng/L. If the striped
                   bass is as  sensitive as some data indicate, it will not be protected by this
                   criterion.
                      The procedures described in the guidelines indicate that, except possi-
                   bly where a locally important species is very sensitive, saltwater aquatic
                   organisms and their uses should not be affected unacceptably if the four-
                   day average concentration of zinc does not exceed 86 ng/L more than once
                   every three years on the average and if the one-hour average concentra-
                   tion does  not exceed  95 ng/L more than once every three years on the
                   average.
                      Criteria for developing water quality-based permit limits and for de-
                   signing waste  treatment facilities must  be applied to an appropriate
                   wasteload allocation model;  dynamic models are preferred. Limited data
                   or other considerations might make their use impractical,  in which case
                   rely on a steady-state model.
                   (52 F.R, 6213, March 2,1987)
                   See Appendix A for Aquatic Life Methodology.
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                                APPENDIX A

                      Derivation of the 1985
                        Aquatic Life Critera
The following is a summary of the Guidelines for Derivation of Criteria for Aquatic Life. The complete text is found in 'G uidelines for
Deriving Numerical National Water Quality Criteria for the Protection of Aquatic Organisms and Their Uses," available from National
Technical Information Service - PB85-227049.

Derivation of numerical national water quality criteria for the protection of aquatic organisms and
their uses is a complex process that uses information from many areas of aquatic toxicology. When a
national criterion is needed for a particular material, all available information concerning toxicity to
and bioaccumulation by aquatic organisms is collected, reviewed for acceptability, and sorted. If
enough acceptable data on acute toxicity to aquatic animals are available, they are used to estimate
the highest one-hour average concentration that should  not result in unacceptable effects on
aquatic organisms and their uses. If justified, this concentration is made a function of water quality
characteristics such  as pH,  salinity, or hardness.  Similarly, data on the chronic toxicity of  the
material to aquatic animals are used to estimate the highest four-day average concentration that
should  not  cause unacceptable  toxicity  during a long-term exposure.  If appropriate, this
concentration is also related to a water quality characteristic.
   Data on toxicity to aquatic plants are examined to  determine whether plants are likely to be
unacceptably affected by  concentrations that should not cause unacceptable effects on animals.
Data on bioaccumulation by aquatic organisms are used to determine if residues might subject
edible species to restrictions by the U.S. Food and Drug Administration (FDA), or if such residues
might harm wildlife that consumes aquatic life. All other available data are examined for adverse
effects that might be biologically important.
   If a thorough review of the pertinent information indicates that enough acceptable data exists,
numerical national water quality criteria are derived for fresh water or salt water or both to protect
aquatic organisms and their uses from unacceptable effects due to exposures to high concentrations
for short periods of time, lower concentrations for longer periods of time, and combinations of the
two.

I.    Definition of Material of Concern

     A.  Each separate chemical that does not ionize substantially in most natural bodies of water
         should usually be considered a separate material,  except possibly for structurally similar
         organic compounds that exist only in large quantities as commercial  mixtures of  the
         various compounds and apparently have similar biological, chemical, physical, and toxi-
         cological properties.

     B.  For chemicals that do ionize substantially in most natural waterbodies (e.g., some phenols
         and organic acids, some salts of phenols and organic acids, and most inorganic salts and
         coordination complexes of metals), all forms in chemical equilibrium should usually be
         considered one  material. Each different  oxidation state of  a metal and each different
         non-ionizable covalently bonded  organometallic  compound   should  usually  be
         considered a separate material.

     C.  The definition of  the material should include an operational  analytical  component.
         Identification of a  material simply, for example,  as "sodium" obviously implies "total
         sodium" but leaves room for doubt. If "total" is meant, it should be explicitly stated. Even

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        "total" has different operational definitions, some of which do not necessarily measure
        "all that is there"  in all sample. Thus, it is also necessary to reference or describe one
        analytical  method that is intended. The operational analytical component should take
        into account the analytical and environmental chemistry of the material, the desirability
        of using the same analytical method on samples from laboratory tests, ambient water and
        aqueous effluents, and various practical considerations such as labor and  equipment
        requirements and whether the method would require measurement in the field or would
        allow measurement after samples are transported to a laboratory.
           The primary requirements  of the operational  analytical component are that it be
        appropriate for use on samples of receiving water, compatible with the available toxicity
        and bioaccumulation data without making overly hypothetical extrapolations, and rarely
        result in underprotection or overprotection of aquatic organisms and their uses. Because
        an ideal analytical measurement will rarely be available, a compromise measurement will
        usually be used. This compromise measurement must fit with the general approach: if an
        ambient concentration is lower than the national  criterion,  unacceptable effects  will
        probably not occur (i.e., the compromise measurement must not err on the side of
        underprotection when measurements are made on a surface water). Because the  chemical
        and  physical properties of an  effluent are usually quite different from those of the
        receiving water, an analytical method acceptable for analyzing an effluent might not be
        appropriate for analyzing a receiving water, and vice versa. If the ambient concentration
        calculated  from a  measured concentration in an effluent is higher than the  national
        criterion, an additional option is to measure the concentration after dilution of the effluent
        with receiving water to determine if the measured concentration  is  lowered by such
        phenomena  as complexation or sorption. A further option,  of course,  is to  derive a
        site-specific criterion. Thus, the criterion should be based on  an appropriate analytical
        measurement, but the criterion is not rendered useless if an ideal measurement either is
        not available or is not feasible.
           The analytical  chemistry of the material might need to be considered when defining
        the material or when judging the acceptability of some toxicity tests, but a criterion should
        not be based on the sensitivity of an analytical method. When aquatic organisms are more
        sensitive  than routine analytical methods, the proper solution is to develop better
        analytical methods, not to underprotect aquatic life.

II.   Collection of Data

     A. Collect all available data on the material concerning toxicity to, and bioaccumulation by,
        aquatic animals and plants; FDA action levels and chronic feeding studies and long-term
        field studies with wildlife species that regularly consume aquatic organisms.

     B. All  data  that are  used should be available in typed,  dated,  and signed  hard copy
        (publication, manuscript, letter, memorandum) with enough supporting information to
        indicate that acceptable  test procedures were used and that the results are probably
        reliable. In some  cases, additional written information from the investigator may be
        needed. Information that  is confidential, privileged, or otherwise not  available for
        distribution should not be used.

     C. Questionable data, whether published or unpublished,  should not be used. Examples
        would be data from tests that did not contain a control treatment, tests in which too many
        organisms in the control treatment died or showed signs  of stress or disease, and tests in
        which distilled or deionized water was used as the dilution water without addition of
        appropriate salts.

     D. Data on technical  grade materials may be used, if appropriate; but data on formulated
        mixtures and emulsifiable concentrates of the material may not be used.

     E. For  some highly  volatile, hydrolyzable, or degradable  materials, only use data  from
       . flow-through tests in which the concentrations of test  material were measured often
        enough with acceptable analytical methods.
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     F.  Data should be rejected if obtained by using:
          • Brine shrimp — because they usually occur naturally only in water with salinity
            greater than 35 g/kg;
          • Species that do not have reproducing wild populations in North America; or
          • Organisms that were previously exposed to substantial concentrations of the test
            material or other contaminants.

     G. Questionable data, data on formulated mixtures and emulsifiable concentrates, and data
        obtained with nonresident species or previously exposed  organisms may be used to
        provide auxiliary information but should not be used in the derivation of criteria.

III.  Required Data

     A. Certain data should be available to help  ensure that each of the four major kinds of
        possible adverse effects receives adequate consideration: results of acute and chronic
        toxicity tests with representative species of aquatic animals are necessary to indicate the
        sensitivities of appropriate untested species. However, since procedures for conducting
        tests with aquatic plants and interpreting the results are not as well developed, fewer data
        concerning toxicity are required. Finally, data concerning bioaccumulation by aquatic
        organisms are required only when relevant information on the significance of residues in
        aquatic organisms is available.

     B. To derive a criterion for freshwater aquatic organisms and their uses, the following should
        be available:

        1.  Results of acceptable acute tests (see section IV) with at least one species of freshwater
            animal in at least eight different families including all of the following:
             • The family Salmonidae in the class Osteichthyes.
             • A second family in the class Osteichthyes, preferably a commercially or
               recreationally important warmwater species, such as bluegill or channel catfish.
             • A third family in the phylum Chordata (may be in the class Osteichthyes or may
               be an amphibian, etc.).

             • A planktonic crustacean such as a cladoceran or copepod.

             • A benthic crustacean (ostracod, isopod, amphipod, crayfish, etc.).

             • An insect (mayfly, dragonfly, damselfly, stonefly, caddisfly, mosquito, midge, etc.).
             • A family in a phylum other than Arthropoda or Chordata, such as Rotifera,
               Annelida, Mollusca.
             • A family in any order of insect or any phylum not already represented.

        2.   Acute-chronic ratios (see section VI) with species of aquatic animals in at least three
             different families, provided that:

             • At least one is a fish;

             • At least one is an invertebrate; and

             • At least one is an acutely sensitive freshwater species (the other two may be
               saltwater species).

         3.   Results of at least one acceptable test with a freshwater alga or vascular plant (see
             section VIII). If the plants are among the aquatic organisms that are most sensitive to
             the material, test data on a plant in  another  phylum (division) should also be
             available.
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        4.  At least one  acceptable bioconcentration factor determined with  an appropriate
            freshwater species, if a maximum permissible tissue concentration is available (see
            section IX).

     C.  To derive a criterion for saltwater aquatic organisms and their uses, the following should
        be available:

        1.  Results of acceptable acute tests (see section IV) with at least one species of saltwater
            animal in at least eight different families, including all of the following:

             •  Two families in the phylum Chordata;

             •  A family in a phylum other than Arthropoda or Chordata;

             •  Either the Mysidae or Penaeidae family;

             •  Three other families not in the phylum Chordata (may include Mysidae or
               Penaeidae, whichever was not used previously); and
             •  Any other family.

        2.  Acute-chronic ratios (see section VI) with species of aquatic animals in at least three
            different families, provided that of the three species:

             •  At least one is a fish;
             •  At least one is an invertebrate; and

             •  At least one is an acutely sensitive saltwater species (the other may be an acutely
               sensitive freshwater species).

        3.  Results of at  least one acceptable test with a saltwater alga or vascular plant (see
            section VIII). If plants are among the aquatic organisms most sensitive to the material,
            results of a test with a plant in another phylum (division) should also be available.

        4.  At least one  acceptable bioconcentration factor determined with  an appropriate
            saltwater species, if a maximum permissible tissue concentration is available (see
            section IX).

     D. If all required data are available, a numerical criterion can usually be derived, except in
        special cases. For example, derivation of a criterion might not be possible if the available
        acute-chronic ratios vary by more than a factor of 10 with no apparent pattern. Also, if a
        criterion is to be related to a water quality characteristic T (see sections V and VII), more
        data will be necessary.
            Similarly, if all required data are not  available, a numerical criterion should not be
        derived except in special cases. For example, even if not enough acute and chronic data
        are available, it might be possible to derive a criterion if the available data clearly indicate
        that the Final Residue Value should be much lower than either the Final Chronic Value or
        the Final Plant Value.

     E.  Confidence in a  criterion usually  increases as the amount of available pertinent data
        increases. Thus, additional data are usually desirable.

IV.  Final Acute Value

     A. Appropriate measures of  the acute (short-term) toxicity of the material to a variety of
        species of aquatic animals are used to calculate the Final Acute Value. The Final Acute
        Value is an estimate of the concentration of the material, corresponding to a cumulative
        probability of 0.05 in the acute toxicity values for genera used in acceptable acute tests
        conducted on the material. However, in some cases, if the Species Mean Acute Value of a
        commercially or recreationally important species is lower than the calculated Final Acute

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    Value, then that Species Mean Acute Value replaces the calculated Final Acute Value to
    protect that important species.

B.  Acute toxicity tests should have been conducted using acceptable procedures such as
    those described in

    1.  ASTM Standard E 729-80, Practice for Conducting Acute Toxicity Tests with Fishes,
       Macroinvertebrates, and Amphibians. American Society for Testing and Materials,
       1916 Race Street, Philadelphia, PA 19103.

    2.  ASTM Standard E 724-80, Practice for Conducting Static Acute Toxicity Tests with
       Larvae of Four Species  of Bivalve Molluscs.  American  Society for Testing  and
       Materials, 1916 Race Street, Philadelphia, PA 19103.

C.  Except for tests with  saltwater annelids and mysids,  do not use results of acute tests
    during which test organisms were fed, unless data indicate that the food did not affect the
    toxicity of the test material.

D.  Results of acute tests conducted in unusual dilution water (e.g., dilution water  in which
    total organic carbon or particulate matter exceeded 5 mg/L) should not be used unless a
    relationship is developed between acute toxicity and organic carbon or particulate matter
    or unless data show that the organic carbon or particulate matter does not affect toxicity.

E.  Acute values should be based on endpoints that reflect the total severe acute adverse
    impact of the test material on the organisms used in the test. Therefore, only the following
    kinds of  data on acute toxicity to aquatic animals should be used:

    1.  Tests with daphnids and other cladocerans should be started with organisms less than
       24-hours old, and tests with midges should be started with second- or third-instar
       larvae. The  result should be the 48-hour EC50 based on  percentage of organisms
       immobilized plus percentage of organisms killed. If such an EC50 is not available
       from a test, the 48-hour LC50 should be used in place of the desired 48-hour EC50. An
       EC50 or LC50 of longer than 48 hours can be used as long as the animals were not fed
       and the control animals were acceptable at the end of the test.

    2.  The  result of a test with embryos and larvae of barnacles, bivalve molluscs (clams,
       mussels, oysters, and scallops), sea urchins, lobsters, crabs, shrimp, and  abalones
       should be the 96-hour EC50 based on the percentage of organisms with incompletely
       developed shells plus the percentage of organisms killed. If such an EC50 is not
       available from a test, the lower  of the  96-hour EC50, based on the percentage of
       organisms with incompletely developed shells and the 96-hour LC50 should be used
       in place of the desired 96-hour EC50. If the duration of the test was between 48 and 96
       hours, the EC50 or LC50 at the end of the test should be used.

    3.  The acute values from tests with all other freshwater and saltwater animal species and
       older life stages of barnacles, bivalve molluscs, sea urchins, lobsters, crabs,  shrimps,
       and  abalones should be  the 96-hour EC50 based  on the  percentage of organisms
       exhibiting loss of equilibrium, plus the percentage of organisms immobilized, plus the
       percentage of organisms killed. If such an EC50 is not available from a test, the 96-hour
       LC50 should be used in place of the desired 96-hour EC50.

    4.  Tests with single-celled organisms are not considered acute tests, even if the  duration
       was  96 hours or less.

    5.  If the tests were conducted properly, acute values reported as "greater than" values
       and  those above the solubility of the test material should be used because rejection of
       such acute values would unnecessarily  lower the Final Acute Value by eliminating
       acute values for resistant species.

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    F.   If the acute toxicity of the material to aquatic animals apparently has been shown to be
        related to a water quality characteristic such  as  hardness or particulate matter for
        freshwater animals or salinity or particulate matter for saltwater animals, a Final Acute
        Equation should be derived based on that water quality characteristic. (Go to section V.)

    G.  If the available data indicate that one or more life stages are at least a factor of 2 more resistant
        than one or more other life stages of the same species, the data for the more resistant life stages
        should not be used in the calculation of the Species Mean Acute Value because a species can be
        considered protected from acute toxicity only if all life stages are protected.

    H.  The agreement of the data within and between species should be considered. Acute values
        that appear to be questionable in comparison with other acute and chronic data for the
        same species and for other species in the same genus probably should not be used in
        calculation of a Species Mean Acute Value. For example, if the acute values available for a
        species or genus differ by more than a factor of 10, some or all of the values probably
        should not be used in calculations.

    I.   For each species for which at least one acute value  is available, the Species Mean Acute
        Value should be calculated as the geometric mean of the results of all flow-through tests in
        which the concentrations of test material were measured. For a species for which no such
        result is available, the Species Mean Acute Value should be calculated as the geometric
        mean of all available acute values — i.e.,  results of flow-through tests in which the
        concentrations were not measured and results of static and renewal tests based on initial
        concentrations  of  test material. (Nominal concentrations are acceptable for most  test
        materials if measured concentrations are not available.)

          NOTE: Data reported by original investigators  should not be rounded off. Results of all
          intermediate calculations should be rounded to four significant digits.
          NOTE: The geometric mean of N numbers is the Nth root of the product of the N numbers.
          Alternatively, the geometric mean can be calculated  by adding the  logarithms of the N
          numbers, dividing the sum by N, and taking the antilog of the quotient. The geometric mean
          of two numbers is the square root of the product of the two numbers, and the geometric mean
          of one number  is that number. Either natural (base e) or common (base  10) logarithms can be
          used to calculate geometric means as long as they are used consistently within each set of data
          (i.e., the antilog used must match the logarithm used).
          NOTE: Geometric means rather than arithmetic means are used here because the distributions
          of individual organisms' sensitivities in toxicity tests on most materials, and the distributions
          of species' sensitivities within a genus, are more likely to be lognormal than normal. Similarly,
          geometric means are used for  acute-chronic ratios and bioconcentration factors because
          quotients are likely to be closer to lognormal than normal distributions. In addition, division of
          the geometric mean of a set of numerators by the geometric mean of the set of corresponding
          denominators will result in the geometric mean of the set of corresponding quotients.

    J.   The Genus Mean Acute Value should be calculated as the geometric mean of the Species
        Mean Acute Values available for each genus.

    K.  Order the Genus Mean Acute Value from high to  low.

    L.  Assign ranks, R, to the Genus  Mean Acute Value from "I" for the lowest to "N" for the
        highest. If two  or more Genus Mean  Acute  Values are identical, arbitrarily assign them
        successive ranks.

    M. Calculate the cumulative probability, P, for each Genus Mean Acute Value as R/ (N+l).

    N. Select the four Genus Mean Acute Values that have cumulative probabilities closest to
        0.05. (If there are less than 59 Genus Mean  Acute Values, these will always be the four
        lowest Genus Mean Acute Values).
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     O. Using the selected Genus Mean Acute Values and Ps, calculate:

             2  £((ln GMAV)2) - ((S(ln GMAV))2/4)
                         Z(P) - ((2(VP))2/4)

            L = (2(lnGMAV)-S(2(VF)))/4

            A = S(VU057 + L
            FAV = eA
        (See original document, referenced at beginning of this appendix, for development of the
        calculation procedure and for an example calculation and computer program.)
          NOTE: Natural logarithms (logarithms to base e, denoted as In) are  used herein merely
          because they are easier to use on some hand calculators and computers than common (base 10)
          logarithms. Consistent use of either will produce the same result.

     P.  If for a commercially or recreationally important species the geometric mean of the acute
        values  from flow-through tests in which the concentrations of test  material were
        measured is lower than the calculated Final Acute Value, then that geometric mean should
        be used as the Final Acute Value instead of the calculated Final Acute Value.

     Q. Go to section VI.

V.   Final Acute Equation

     A. When enough data are available to show that acute toxicity to two or more species is similarly
        related to a water quality characteristic,  the relationship should  be  taken into account as
        described in section IV, steps B through G, or using analysis of covariance. The two methods
        are equivalent and produce identical results. The manual method described below provides
        an  understanding of this application  of covariance analysis, but computerized versions of
        covariance analysis are much more convenient for analyzing large data tests. If two or more
        factors affect toxicity, multiple regression analysis should be used.

     B. For each species for which comparable acute toxicity values are available  at two or more
        different values of the water quality characteristic, perform a least  squares regression of
        the acute toxicity values on the corresponding values of the water quality characteristic to
        obtain the slope and its 95 percent confidence limits for each species.
          NOTE: Because the best documented relationship is that between hardness and acute toxicity
          of metals in freshwater and a log-log relationship fits these data, geometric means and natural
          logarithms of  both toxicity and water quality are used in the rest of this  section. For
          relationships based on other water quality characteristics such as pH,  temperature, or salinity,
          no transformation or a different transformation might fit the data  better, and appropriate
          changes will be necessary.

     C. Decide whether the data for each species are useful,  taking into account the range and
        number of the tested values of the water quality characteristic and  the degree of
        agreement within and between species. For example, a slope based on six data points
        might be of limited value if based only on data for a very narrow range of water quality
        characteristic values. A slope based on only two data points, however, might be useful if
        consistent with other information and if the two points cover a broad enough range of the
        water quality characteristic.
            In addition, acute values  that appear to be questionable in comparison with other
        acute and chronic data available for the same species and for other species in the same
        genus probably should not be used. For example, if after adjustment for the water quality
        characteristic the acute values available for a species or genus differ by more than a factor
        of  10, probably some or all of the values should be rejected.  If useful  slopes are  not
        available for at least one fish and one invertebrate, or if the  available  slopes are  too
         dissimilar, or if too few data are available to adequately define the  relationship between

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        acute toxicity and the water quality characteristic, return to section IV.G, using the results
        of tests conducted under conditions and in waters similar to those commonly used for
        toxicity tests with the species.

    D.  Individually for each species, calculate the geometric mean of the available acute values
        and then divide each of these acute values by the mean for the species. This normalizes the
        values so that the geometric mean of the normalized values for each species, individually,
        and for any combination of species is 1.0.

    E.  Similarly normalize the values of the water quality characteristic for each species,
        individually.

    F.  Individually for each species, perform a least squares regression of the normalized acute
        toxicity  values on the  corresponding  normalized  values of  the  water quality
        characteristic. The resulting slopes and 95 percent confidence limits will be identical to
        those obtained in step B. However, now, if the data are actually plotted, the line of best fit
        for each individual species will go through the point 1,1 in the center of the graph.

    G.  Treat the normalized data as if they were all for the same species and perform a least
        squares regression of all the normalized acute  values on the corresponding normalized
        values of the water quality characteristic to obtain the pooled acute slope, V, and its 95
        percent confidence limits. If all the normalized data are actually plotted, the line of best fit
        will go through the point 1,1 in the center of the graph.

    H.  For each species, calculate the geometric mean, W, of the acute toxicity values and the
        geometric mean, X, of the  values  of the  water quality characteristic.  (These were
        calculated in steps D and E.)

    I.  For each species, calculate the logarithm, Y, of the Species Mean Acute Value at a selected
        value, Z, of the water quality characteristic using the equation:

                                  Y = lnW-V(lnX-lnZ).

    J.  For each species, calculate the SMAV at Z using the equation:
                                       SMAV = e?.
          NOTE: Alternatively, the Species Mean Acute Values at Z can be obtained by skipping step H,
          using the equations in steps I and J to adjust each acute value individually to Z, and then
          calculating the geometric mean of the adjusted values for each species individually.

        This alternative procedure allows an examination  of the range of the adjusted acute
        values for each  species.

    K.  Obtain the Final Acute Value at Z by using the procedure  described in  section IV, steps J
        through O.

    L.  If the Species Mean Acute Value at Z of a commercially or recreationally important species
        is lower than the calculated Final Acute Value  at Z, then that Species Mean Acute Value
        should be used as the Final Acute Value at Z instead of the calculated Final Acute Value.

    M. The Final Acute Equation is written as:
                Final Acute Value = e(V'ln(water 1uality characteristic)]  + In A - V[ln Z])
            where

              V = pooled acute slope
              A = Final Acute Value at Z.
        Because V, A, and Z are known, the Final Acute Value can be calculated for any selected
        value of the water quality characteristic.
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VI.  Final Chronic Value

     A.  Depending on the data that are available concerning chronic toxicity to aquatic animals,
         the Final Chronic Value might be calculated in the same manner as the Final Acute Value
         or by dividing the Final Acute Value by the Final Acute-Chronic Ratio. In some cases, it
         may not be possible to calculate a Final Chronic Value.
          NOTE: As  the name implies, the Acute-Chronic Ratio is a way of relating acute and chronic
          toxicities. The Acute-Chronic Ratio is basically the inverse of the application factor, but this
          new name is better because it is more descriptive and should help prevent confusion between
          "application factors" and "safety factors." Acute-Chronic Ratios and application factors are
          ways of relating the acute and chronic toxicities of a material to aquatic organisms. Safety
          factors are used to  provide an extra margin of  safety beyond  the known or estimated
          sensitivities of aquatic organisms. Another advantage of the Acute-Chronic Ratio is that it will
          usually be  greater than 1; this should avoid the  confusion as to whether a large application
          factor is one that is close to unity or one that has  a denominator that is much greater than the
          numerator.

     B.  Chronic values should be based on results of flow-through chronic tests in which the
         concentrations  of  test material in  the test  solutions were properly measured at
         appropriate times during the test. (Exception:  renewal, which is acceptable for daphnids.)

     C.  Results of chronic tests in which survival, growth, or reproduction in the control treatment
         was unacceptably low should not be used. The limits of acceptability will depend on the
         species.

     D.  Results of chronic tests conducted in unusual dilution water (e.g., dilution water in which
         total organic carbon or particulate matter exceeded 5 mg/L) should not be used, unless a
         relationship is developed  between chronic toxicity and organic carbon or particulate
         matter, or unless data show that organic  carbon, particulate matter (and so forth) do not
         affect toxicity.

     E.  Chronic values should be based on endpoints and lengths of exposure appropriate to the
         species. Therefore, only results of the following kinds of chronic toxicity tests should be
         used:

         1.   Life-cycle toxicity tests consisting of exposures of each of two or more  groups of
             individuals of a species to a different concentration of the test material throughout a
             life cycle. To ensure that all life stages and life processes are exposed, tests with fish
             should begin with embryos or newly hatched young less than 48-hours old, continue
             through maturation and reproduction, and end not  less  than  24 days  (90 days for
             salmonids) after the hatching of the next generation. Tests with daphnids should
             begin with young less than 24-hours  old and last for not less than 21 days. Tests with
             mysids should begin with young less than 24-hours old and continue until seven days
             past the median time of first brood release in the controls.
                For fish, data should be obtained and  analyzed on survival and growth of adults
             and young, maturation of males and  females, eggs spawned per female, embryo
             viability (salmonids only), and hatchability. For daphnids, data should be obtained
             and analyzed on survival and young per female. For mysids, data should be
             obtained and analyzed on survival, growth, and young per female.

         2.   Partial life-cycle toxicity tests consisting of exposures of each of two or more groups of
             individuals in a fish species to a concentration of the test material through most
             portions of a life cycle. Partial life-cycle tests are allowed with fish species that require
             more than a year to reach sexual maturity so that all major life stages can be exposed to
             the test material in less than 15 months.
                Exposure to the test material should begin with immature juveniles at least two
             months prior to active gonad development, continue through maturation and
             reproduction, and end not less than 24 days (90 days for salmonids) after the
             hatching of the next generation. Data should be obtained and analyzed on survival
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            and growth of adults and young, maturation of males and females, eggs spawned
            per female, embryo viability (salmonids only), and hatchability.

        3.   Early life-stage toxicity tests  consisting of 28 to 32-day (60 days post hatch for
            salmonids) exposures of the early life stages of a fish species from shortly after
            fertilization through embryonic, larval, and early juvenile development. Data should
            be obtained and analyzed on survival and growth.
            NOTE: Results of an early life-stage test are used as predictions of results of life-cycle and
            partial life-cycle tests with the same species. Therefore, when results of a total or partial
            life-cycle test are available, results of an early life-stage test with the same species should
            not be used. Also, results of early life-stage tests in which the incidence of mortalities or
            abnormalities increased substantially near the end should not be used because  these
            results are possibly not good predictions of the results of comparable life-cycle or partial
            life-cycle tests.

    F.  A chronic value can be obtained by calculating the geometric mean of the lower and upper
        chronic limits from a chronic test or by analyzing chronic data using regression analysis. A
        lower chronic limit is the highest tested concentration in an acceptable chronic test that did
        not cause an unacceptable amount of adverse effect on any of the specified biological
        measurements and below which no tested concentration caused an unacceptable effect. An
        upper chronic limit is the lowest tested concentration in an acceptable chronic test that did
        cause an unacceptable amount of adverse effect on one or more of the specified biological
        measurements and above which all tested concentrations also caused such an effect.
         NOTE: Because various authors have used a variety of terms and definitions to interpret and
         report results of chronic tests, reported results should be reviewed carefully. The amount of
         effect that is considered unacceptable is often based on a statistical hypothesis test but might
         also be defined in terms of a specified percent reduction from the controls. A small percent
         reduction (e.g., 3 percent) might be considered acceptable even if it is statistically significantly
         different from the control, whereas a large  percent  reduction (e.g.,  30 percent) might be
         considered unacceptable even if it is not statistically significant.

    G.  If the chronic toxicity of the material to aquatic animals apparently has been shown to be
        related to a water quality characteristic  such as hardness or  particulars  matter for
        freshwater animals or salinity or particulate matter for saltwater animals, a Final  Chronic
        Equation should be derived based  on that water quality characteristic. Go to section VII.

    H. If chronic values are available for species in eight families as described in sections III.B.l or
        III.C.I, a Species Mean Chronic Value should also be calculated for each species for which
        at least one chronic value is available by calculating the geometric mean  of all chronic
        values available for the species;  appropriate Genus Mean Chronic Values should also be
        calculated.  The Final Chronic  Value should  then be obtained using the  procedure
        described in section III, steps J through O. Then go to section VI.M.

    I.  For each chronic value for which  at least one corresponding appropriate acute  value is
        available, calculate an acute-chronic ratio using for the numerator the geometric  mean of
        the results of all  acceptable flow-through acute tests in the same dilution water and in
        which the concentrations were measured. (Exception: static is acceptable for daphnids.)
            For fish, the acute test(s) should have been conducted with juveniles and should have
        been part of the same study as the chronic test. If acute tests were not conducted as part of
        the same study, acute tests conducted in the same laboratory and dilution water but in a
        different study may be used. If no such acute tests are available, results of acute  tests
        conducted in the same dilution water in a different laboratory may be used. If  no such
        acute tests are available, an acute-chronic ratio should not be calculated.

    J.  For each species, calculate the species mean acute-chronic ratio as the geometric  mean of
        all acute-chronic ratios available for that species.
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     K.  For some materials, the acute-chronic ratio seems to be the same for all species, but for
        other materials, the ratio seems to increase or decrease as the Species Mean Acute Value
        increases. Thus the Final Acute-Chronic Ratio can be obtained in four ways, depending on
        the data available:

        1.   If the Species Mean Acute-Chronic ratio seems to increase or decrease as the Species
            Mean Acute Value increases, the Final Acute-Chronic Ratio should be calculated as the
            geometric mean of the acute-chronic ratios for species whose Species Mean Acute
            Values are close to the Final Acute Value.

        2.   If no major trend is apparent, and the acute-chronic ratios for a number of species are
            within  a factor of 10,  the Final Acute-Chronic Ratio should be calculated as the
            geometric mean of all the Species  Mean Acute-Chronic Ratios available  for both
            freshwater and saltwater species.

        3.   For acute tests conducted on metals and possibly other substances with embryos and
            larvae  of  barnacles, bivalve molluscs, sea urchins, lobsters,  crabs, shrimp,  and
            abalones  (see  section  IV.E.2),  it is  probably appropriate to assume  that the
            acute-chronic ratio is 2. Chronic tests are very difficult to conduct with most such
            species, but the sensitivities of embryos and larvae would likely determine the results
            of  life-cycle  tests. Thus, if the lowest available Species Mean  Acute  Values  were
            determined with embryos and larvae of such species, the Final Acute-Chronic Ratio
            should probably be assumed to be 2, so that the Final Chronic Value is equal to the
            Criterion Maximum Concentration (see section XI.B)

        4.   If the most appropriate Species Mean Acute-Chronic Ratios are less than 2.0, and
            especially if they are less than 1.0, acclimation has probably occurred during the
            chronic test. Because continuous exposure and acclimation cannot be assured to
            provide adequate protection in field situations, the Final Acute-Chronic Ratio should
            be assumed to be 2, so that the Final Chronic Value is equal to the Criterion Maximum
            Concentration (see section XI.B).
               If the available Species Mean Acute-Chronic Ratios do not fit one of these cases, a
            Final Acute-Chronic Ratio probably cannot be obtained, and a Final Chronic Value
            probably cannot be calculated.

     L.  Calculate the Final  Chronic  Value by dividing the  Final Acute  Value by the  Final
        Acute-Chronic Ratio. If there was a Final Acute Equation rather than a Final Acute Value,
        see also section VII. A.

     M. If the Species Mean Chronic Value of a commercially or recreationally important species is
        lower  than the calculated  Final Chronic Value, then that Species Mean Chronic Value
        should be used as the Final Chronic Value instead of the calculated Final Chronic Value.

     N. Go to section VIII.

VII. Final Chronic Equation

     A. A Final Chronic Equation can be derived in two ways. The procedure described here will
        result in the chronic slope being the same as the acute slope. The procedure described in
        steps B through N usually will result in the chronic slope being different from the acute
        slope.
        1.   If acute-chronic ratios are available for enough species at enough values of the water
            quality characteristic to indicate that the acute-chronic ratio is probably the same for
            all species and is probably independent of the water quality characteristic, calculate
            the Final Acute-Chronic Ratio as the geometric mean of the available Species Mean
            Acute-Chronic Ratios.
        2.   Calculate  the  Final Chronic Value at the selected value Z of the water quality
            characteristic by dividing the Final Acute Value at Z (see section V.M) by the Final
            Acute-Chronic Ratio.
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        3.  Use V = pooled acute slope (see section V.M) as L = pooled chronic slope.

        4.  Go to section VII.M.

    B.  When enough data are available to show that chronic toxicity to at least one species is
        related to a water quality characteristic, the relationship should be taken into account as
        described in steps  B  through G or using analysis of covariance. The two methods are
        equivalent and produce identical results. The manual method described in the following
        paragraphs provides an understanding of this  application of covariance analysis, but
        computerized versions of covariance analysis are much more convenient for analyzing
        large data sets. If two or more factors affect toxicity, multiple regression analysis should be
        used.

    C.  For each species for which comparable chronic toxicity values are available at two or more
        different values of the water quality characteristic, perform a least squares regression of
        the chronic toxicity values on the corresponding values of the water quality characteristic
        to obtain the slope and its 95 percent confidence limits for each species.
         NOTE: Because the best-documented relationship is that between hardness and acute toxicity
         of metals in fresh water and a log-log relationship fits these data, geometric means and natural
         logarithms of both toxicity and water quality are used in the rest of this section. For
         relationships based on other water quality characteristics such as pH, temperature, or salinity,
         no transformation  or a different transformation might fit the data better, and appropriate
         changes will be necessary throughout this section. It is probably preferable, but not necessary,
         to use the same transformation that was used with the acute values in section V.

    D.  Decide whether the data for each species are useful, taking into account the range and
        number of the  tested values of the water quality characteristic and  the degree of
        agreement  within and between species. For example,  a slope based on six  data points
        might be of limited value if based only on data for a very narrow range of values of the
        water quality characteristic. A slope based on only two data points, however, might be
        useful if it is consistent with other information and if the two points cover a broad enough
        range of  the  water quality characteristic. In addition,  chronic values that appear to be
        questionable in  comparison with other acute and chronic data available for the same
        species and for other species in the same genus probably should not be used. For example,
        if after adjustment for the water quality characteristic the chronic values available for a
        species or genus differ by more than a factor of 10, probably some or all of the values
        should be rejected.
           If a useful chronic slope is not available for at least one species, or if the available
        slopes are  too dissimilar, or if  too  few data are  available to adequately define the
        relationship between chronic toxicity and the water quality characteristic,  the chronic
        slope is probably the same as the acute slope, which is equivalent to assuming that the
        acute-chronic ratio is independent of the water quality characteristic. Alternatively, return
        to section VI.H, using the results of tests conducted  under conditions  and in waters
        similar to those commonly used for toxicity tests with the species.

    E.  Individually for each species, calculate the geometric mean of the available chronic values
        and then divide  each chronic value for a species  by its mean. This normalizes the chronic
        values so that the geometric mean of the normalized values for each species individually,
        and for any combination of species, is 1.0.

    F.  Similarly normalize  the values of the water  quality characteristic for each  species,
        individually.

    G.  Individually for each species,  perform a least squares regression  of the  normalized
        chronic toxicity values on the corresponding normalized values of  the water  quality
        characteristic. The resulting slopes and the 95 percent confidence limits will be identical to
        those obtained in section B. Now, however, if the data are actually plotted, the line of best
        fit for each individual species will go through the point 1,1 in the center of the graph.
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     H. Treat all the normalized data as if they were all for the same species and perform a least
        squares regression of all the normalized chronic values on the corresponding normalized
        values of the water quality characteristic to obtain the pooled chronic slope, L, and its 95
        percent confidence b'mits. If all the normalized data are actually plotted, the line of best fit
        will go through the point 1,1 in the center of the graph.

     I.  For each species, calculate the geometric mean, M, of the toxicity values and the geometric
        mean, P, of the values of the water quality characteristic. (These were calculated in steps E
        and F.)

     J.  For each species, calculate the logarithm, Q, of the Species  Mean Chronic Value at a
        selected value, Z, of the water quality characteristic using the equation:
                                   Q = lnM-L(lnP-lnZ).
          NOTE: Although it is not necessary, it will usually be best to use the same value of the water
          quality characteristic here as was used in section V.I.

     K. For each species, calculate a Species Mean Chronic Value at Z using the equation:
                                        SMCV = eQ.
          NOTE: Alternatively, the Species Mean Chronic Values at Z can be obtained by skipping step J,
          using  the  equations in steps J and K to adjust each acute  value individually to Z, and then
          calculating the geometric means of the adjusted values for each species individually. This
          alternative procedure allows an examination of the range  of the adjusted chronic values for
          each species.

     L. Obtain the Final Chronic Value at Z by using the procedure described in section IV, steps J
        through O.

     M. If the Species Mean Chronic Value at Z of a  commercially or recreationally  important
        species is lower than  the calculated Final Chronic Value at Z, then that Species Mean
        Chronic Value should be used as the Final Chronic Value at Z instead of the  calculated
        Final Chronic Value.

     N. The Final Chronic Equation is written as:
                Final Chronic Value = e(LIln(water 1uality characteristic)] + In S - L[ln Z])
        where
           L = pooled chronic slope
           S = Final Chronic Value at Z.
        Because L, S, and Z are known, the Final Chronic Value can be calculated for any selected
        value of the water quality characteristic.

VIII.Final Plant Value

     A. Appropriate measures of the toxicity of the material to aquatic plants are used to compare the
        relative sensitivities of aquatic plants and animals. Although procedures for conducting  and
        interpreting the results of toxicity tests with plants are not well developed, results of tests with
        plants usually indicate that criteria which adequately protect aquatic animals and their uses
        will probably also protect aquatic plants and their uses.

     B. A plant value is the result of  a 96-hour test conducted with an alga, or a chronic  test
        conducted with an aquatic vascular plant.
          NOTE: A test of the toxicity of a metal to a plant usually should not be  used if the medium
          contained an excessive amount of a complexing agent,  such as EDTA, that might affect the
          toxicity of the metal. Concentrations of EDTA above about 200 ng/L should probably be
          considered excessive.

     C. The Final Plant Value should be obtained by selecting the lowest result from a test with an
         important  aquatic plant  species in which the  concentrations of test material were
         measured, and the endpoint was biologically important.
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IX.   Final Residue Value

     A. The Final Residue Value is intended to prevent concentrations in  commercially  or
        recreationally important aquatic species from affecting marketability because they exceed
        applicable FDA action  levels and to protect wildlife (including fishes and birds) that
        consume aquatic organisms from demonstrated unacceptable effects. The Final Residue
        Value is the  lowest of the residue  values that are obtained by dividing maximum
        permissible tissue concentrations by appropriate bioconcentration or bioaccumulation
        factors.  A maximum permissible tissue concentration is either (a) an  FDA action level
        (Compliance Policy Guide, U.S. Food & Drug Admin. 1981) for fish oil or for the edible
        portion  of fish or shellfish, or a maximum acceptable dietary intake based on  observations
        on survival, growth, or reproduction in a chronic wildlife feeding study or a long-term
        wildlife field  study. If no maximum permissible tissue concentration is available, go to
        section X because no Final Residue Value can be derived.

     B. Bioconcentration Factors (BCFs) and bioaccumulation factors (BAFs) are quotients of the
        concentration of a material in one or more tissues of an aquatic organism, divided by the
        average concentration in the solution in which the organism had been living. A BCF is
        intended to account only for net uptake directly from water and thus almost must be
        measured in a laboratory test. Some uptake during the bioconcentration test might not be
        directly from water if the food sorbs some of the test material before it is eaten by the test
        organisms. A BAF is intended to account for net uptake from both food and water in a
        real-world  situation.  A BAF almost must be  measured in a field  situation  in which
        predators accumulate the material directly from water and by consuming prey that could
        have accumulated the material from both food and water.
            The BCF and BAF are probably similar for a material with a low BCF, but the BAF is
        probably higher than the BCF for materials with high BCFs. Although BCFs are not too
        difficult to determine, very few BAFs have been measured acceptably because adequate
        measurements must be  made of the material's concentration in water to ascertain if it was
        reasonably constant for a long enough time over the range of territory inhabited by the
        organisms. Because so  few  acceptable BAFs are available, only BCFs will be discussed
        further.  However, if an acceptable BAF is available for a material, it should be used instead
        of any available BCFs.

     C. If a maximum permissible tissue concentration is available for a substance (e.g., parent
        material, parent material plus metabolites, etc.), the tissue concentration used in the
        calculation of  the BCF should be for the  same substance.  Otherwise, the  tissue
        concentration used in the calculation of the BCF should derive from the material and its
        metabolites that are structurally similar and are not much more soluble in water than the
        parent material.

     D.I.  A BCF should be used only if the test was flow-through, the BCF was calculated based
            on measured concentrations of the test material in tissue and in the test solution, and
            the  exposure continued at least  until either apparent steady state or  28 days was
            reached. Steady state is  reached when the BCF does not change significantly over a
            period of time, such as 2 days or 16 percent of the length of the exposure, whichever is
            longer. The BCF used from a test should be the highest of the apparent steady-state
            BCF, if apparent steady state was  reached; the highest BCF obtained, if apparent
            steady state was not reached; and the projected steady state BCF, if calculated.

        2.  Whenever a BCF is determined for a lipophilic material, the percent lipids should also
            be determined in the tissue(s) for which the BCF was calculated.

        3.  A BCF obtained from an exposure that adversely affected the test organisms may be
            used only if it is similar to a BCF obtained with unaffected organisms of the same
            species at lower concentrations that did not cause adverse effects.

        4.  Because maximum permissible tissue concentrations are almost never based  on dry
            weights, a BCF calculated using dry tissue weights must be converted to a wet tissue
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       weight basis. If no conversion factor is reported with the BCF, multiply the dry weight
       BCF by 0.1 for plankton and by 0.2 for individual species of fishes and invertebrates.

   5.  If more than one acceptable BCF is available for a species, the geometric mean of the
       available values should be used; however, if the BCFs are from different lengths of
       exposure and the BCF increases with length of exposure, then the BCF for the longest
       exposure should be used.

E. If enough pertinent data exist, several residue values can be calculated by dividing
   maximum permissible tissue concentrations by appropriate BCFs:

   1.  For each available maximum acceptable dietary intake derived from a chronic feeding
       study or a long-term field study with wildlife (including birds and aquatic organisms),
       the appropriate BCF is based on the whole body of aquatic species that constitute or
       represent a major portion of the diet of the tested wildlife species.

   2.  For an FDA action level  for fish  or shellfish, the appropriate BCF is the highest
       geometric mean species BCF for the edible portion (muscle for decapods, muscle with
       or without skin for fishes, adductor muscle for scallops, and total soft tissue for other
       bivalve molluscs) of a consumed species. The highest species BCF is used because FDA
       action levels are applied on a species-by-species basis.

F. For lipophilic materials, calculating additional residue values  is possible. Because  the
   steady-state BCF for a lipophilic material seems to be proportional to percent lipids from
   one tissue to another and from one species to another, extrapolations  can be made from
   tested tissues, or species to untested tissues, or species on the basis of percent lipids.

   1.  For each BCF for which the percent lipids is known for the same tissue for which the
       BCF was measured, normalize the BCF to a 1 percent lipid basis by dividing it by the
       percent lipids. This adjustment to a 1 percent lipid basis is intended to make all the
       measured BCFs for a material comparable regardless of the species or tissue with
       which the BCF was measured.
   2.  Calculate the geometric mean  normalized BCF. Data  for  both saltwater and
       freshwater species should be used to determine the mean normalized BCF unless they
       show that the normalized BCFs are probably not similar.
   3.  Calculate all possible residue values by dividing the available maximum permissible
       tissue concentrations by the mean normalized BCF and by the percent lipids values
       appropriate to the maximum permissible tissue concentrations, i.e.,
            _  .,     .       (maximum permissible tissue concentration)
           Residue value - —i	c	—
                         (mean normalized BCF)(appropriate percent lipids)

        •  For an FDA action level for fish oil, the appropriate percent lipids value is 100.

        •  For an FDA action level for fish, the appropriate percent lipids value is 11 for
          freshwater criteria and 10 for saltwater criteria because FDA action levels are
          applied species-by-species to commonly consumed species. The highest lipid
          contents in the edible portions of important consumed species are about 11
          percent for both the freshwater chinook salmon and lake trout and about 10
          percent for the saltwater Atlantic herring.
        •  For a maximum acceptable dietary intake derived from a chronic feeding study or
          a long-term field study with wildlife, the appropriate percent lipids is that of an
          aquatic species or group of aquatic species that constitute a major portion of the
          diet of the wildlife species.

G. The Final Residue Value is obtained by selecting the lowest of the available residue values.
     NOTE: In some cases, the Final Residue Value will not be low enough. For example, a residue
     value calculated from a FDA action level will probably result in an average concentration in
     the edible portion of a fatty species at the action  level. Some individual organisms and
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          possibly some species will have residue concentrations higher than the mean value, but no
          mechanism has been devised to provide appropriate additional protection. Also, some chronic
          feeding studies and long-term field studies with wildlife identify concentrations that cause
          adverse effects but do not identify concentrations that do not cause adverse effects; again, no
          mechanism has been devised to provide appropriate additional protection. These are some of
          the species and uses that are not protected at all times in all places.

X.   Other Data
     Pertinent information that could not be used in earlier sections might be available concerning
     adverse effects on aquatic organisms and their uses. The most important of these are data on
     cumulative and delayed  toxicity,  flavor impairment, reduction  in  survival,  growth, or
     reproduction, or any other adverse effect shown to  be  biologically important. Especially
     important are data for species for which no other data are available. Data from behavioral,
     biochemical, physiological, microcosm, and field studies might also be available. Data might be
     available from tests conducted in unusual dilution water (see IV.D and VI.D), from chronic tests
     in which the concentrations were not measured (see VLB), from tests with previously exposed
     organisms (see II.F), and from tests  on formulated mixtures or emulsifiable concentrates (see
     II.D). Such data might affect a criterion if they were obtained with an important species, the test
     concentrations were measured, and the endpoint was biologically important.

XI.  Criterion

     A.  A criterion consists of two concentrations: the Criterion Maximum Concentration and the
         Criterion Continuous Concentration.

     B.  The Criterion Maximum Concentration (CMC) is equal to one-half the Final Acute Value.

     C.  The Criterion Continuous Concentration  (CCC) is equal to  the lowest of the Final Chronic
         Value, the Final Plant Value, and the Final Residue Value, unless other data (see section X)
         show that a lower value should be used. If toxicity is related to a water quality characteristic,
         the Criterion Continuous Concentration is obtained from the Final Chronic Equation, the
         Final Plant Value, and the Final Residue Value by selecting the one, or the combination, that
         results in the lowest concentrations in the usual  range of the water quality characteristic,
         unless other data (see section X) show that a lower value should be used.

     D.  Round both  the Criterion Maximum  Concentration and the Criterion Continuous
         Concentration to two significant digits.

     E.  The criterion is stated as follows:
         The procedures described in the "Guidelines for Deriving Numerical  National Water
         Quality Criteria for the Protection of Aquatic Organisms  and Their Uses" indicate that,
         except possibly where a locally important species is very sensitive, (1) aquatic organisms
         and their uses should not be affected unacceptably if the four-day average concentration
         of (2) does not exceed (3) ug/L more than once every three years on the average, and if the
         one-hour average concentration does not exceed  (4)  ng/L more than once every three
         years on the average.

          where   (1) = insert freshwater or saltwater
                  (2) = insert name of material
                  (3) = insert the Criterion Continuous Concentration
                  (4) = insert the Criterion Maximum Concentration.

XII. Final Review

     A.  The derivation of the criterion should be carefully reviewed by rechecking each step of the
         guidelines. Items that should be especially checked are

         1.  If unpublished data are used, are they well documented?

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   2.  Are all required data available?
   3.  Is the range of acute values for any species greater than a factor of 10?
   4.  Is the range of Species Mean Acute Values for any genus greater than a factor of 10?
   5.  Is there more than a factor of 10 difference between the four lowest Genus Mean Acute
       Values?
   6.  Are any of the four lowest Genus Mean Acute Values questionable?
   7.  Is the Final Acute Value reasonable in comparison with the Species Mean Acute Values
       and Genus Mean Acute Values?
   8.  For any commercially or recreationally important species, is the geometric mean of
       the acute values from flow-through tests in which the concentrations of test material
       were measured lower than the Final Acute Value?
   9.  Are any of tne chronic values questionable?
   10. Are chronic values available for acutely sensitive species?
   11. Is the range of acute-chronic ratios greater than a factor of 10?
   12. Is the Final Chronic Value reasonable in comparison with  the available acute and
       chronic data?
   13. Is the measured  or predicted chronic value for any commercially or recreationally
       important species below the Final Chronic Value?
   14. Are any of the other data important?
   15. Do any data look like they might be outliers?
   16. Are there any deviations from the guidelines? Are they acceptable?
B. On the basis of all available pertinent laboratory and field information, determine if the
   criterion is consistent with sound scientific  evidence. If not, another criterion — either
   higher or lower — should be derived using appropriate modifications of these guidelines.
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                                APPENDIX  B

                      Derivation of the 1980
                       Aquatic Life Criteria
This version of the Guidelines provides clarifications, additional details, and technical and editorial
changes in the last version published in the Federal Register [44 FR 15970 (March 15, 1979)]. It
incorporates changes resulting from comments on previous versions and from experience gained
during EPA's use of the previous versions. Future versions of the Guidelines will incorporate new
ideas and data as their usefulness is demonstrated.
    Criteria may be  expressed in several forms. The numerical form is commonly used, but
descriptive and procedural forms can be used if numerical criteria are not possible or desirable. The
purpose of these Guidelines is to describe an objective, internally consistent and appropriate way of
deriving numerical water quality  criteria for the protection of the  uses and presence of aquatic
organisms.
    A numerical criterion is an estimate of the highest concentration of a substance in water that
does not present a significant risk to the aquatic organisms in the water and their uses. Thus the
Guidelines are intended to derive criteria that will protect aquatic communities by protecting most
of the species and their uses most of the time, but not necessarily all of the species all  of the time.
Aquatic communities can tolerate some stress and occasional adverse effects on a few species, and
so total protection of all species all of the time is not necessary. Rather, the Guidelines  attempts to
provide a reasonable  and adequate amount of protection with only a small  possibility of
considerable overprotection or underprotection. Within these constraints, it seems appropriate to
err on the side of overprotection.
    The numerical aquatic life criteria derived using the Guidelines are expressed as two numbers,
rather than the traditional one number, so that the criteria can more accurately reflect lexicological
and practical realities. The combination of both a maximum value and a 24-hour average value is
designed to provide adequate protection of aquatic life and its uses from acute and chronic toxicity
to animals, toxicity to plants, and bioconcentration by aquatic organisms without the restrictions of
a one-number criterion to provide the same amount of protection. The only way to assure the same
degree of protection with  a one-number criterion would be  to use the 24-hour average as a
concentration that is not to be exceeded at any time in any place.
    The two-number criterion is intended to  identify an  average pollutant concentration that will
produce a water quality  generally suited to the maintenance of aquatic life and its  uses, while
restricting the extent and duration of excursions over the average so that the total exposure will not
cause unacceptable adverse effects. Merely  specifying  an average value over a time period is
insufficient, unless the period of time is rather short, because concentration higher than  the average
value can kill or cause substantial damage in short periods. Furthermore,  for some substances the
effect of intermittent high exposures is cumulative. Therefore, placing an upper limit on pollutant
concentrations to which  aquatic organisms might be exposed is necessary, especially when the
maximum value is not much higher than the average value. For some substances, the maximum may
be so much higher than the 24-hour average that in any real-world situation the maximum will never
be reached if the 24-hour average is achieved. In such cases, the 24-hour average will be limiting and
the maximum will have no practical significance, except to indicate that elevated concentrations are
acceptable as long as the 24-hour average is achieved.
    These Guidelines have been developed on the assumption that the results of laboratory tests are
generally useful for predicting what will happen in field situations. The resulting criteria are meant to
apply to most U.S. bodies of water, except for the Great Salt Lake. All aquatic organisms and their
common uses are meant to be considered, but not necessarily protected, if relevant data are available,
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with at least one specific exception. This exception  is the accumulation  of residues  of organic
compounds in the siscowet subspecies of lake trout which occurs in Lake Superior and contains up to 67
percent fat in the fillets (Thurston, C.E., 1962, Physical Characteristics and Chemical Composition of
Two Subspecies of Lake Trout, J. Fish. Res. Bd. Canada 19:39-44). Neither siscowet nor organisms in the
Great Salt Lake are intentionally protected by these Guidelines because both may be too atypical.
    With appropriate  modifications, these Guidelines can be used  to derive criteria for  any
specified geographical area, body of water (such as the Great Salt Lake), or group of similar bodies
of water. Thus, with appropriate modifications, the Guidelines can be used to derive national, state,
or local criteria if adequate information is available concerning  the  effects of the substance of
concern on appropriate species and their uses. However, the basic concepts described in the
Guidelines should be modified only when  sound scientific evidence indicates that a criterion
produced  using the Guidelines would probably significantly overprotect or underprotect the
presence or uses of aquatic life.
    Criteria produced by these Guidelines are  not enforceable numbers. They may be used in
developing  enforceable numbers, such  as  water  quality standards and effluent  standards.
However, the development of standards may take into account additional factors such as social,
legal, economic, and hydrological considerations, the environmental and analytical chemistry of
the substance, the extrapolation from laboratory data to field situations, and the relationship
between the species for which data are available and the species to be protected.
    Because fresh water and salt water (including both estuarine and marine waters) have basically
different chemical compositions and because freshwater and saltwater species rarely inhabit the
same water simultaneously, separate criteria should be derived  for these two kinds of waters.
However, for some substances sufficient data may not be available to allow derivation of one or
both of these criteria using the Guidelines.
    These Guidelines are meant to be used after a decision is made that a criterion is needed for a
substance. The Guidelines do not address the rationale for making that decision. If the potential for
adverse effects on aquatic life and its uses  are part of the basis for  deciding whether or not a
criterion is needed for a substance, these Guidelines may be helpful in collecting and interpretating
relevant data.

I.   Define the Substance for Which the Criterion is to be Derived

     A.  Each separate chemical that would not ionize significantly in most natural bodies of water
         should usually be considered a separate substance, except possibly for structurally similar
         organic compounds that only differ in the  number and  location of atoms of a specific
         halogen,  and only exist in large  quantities as commercial mixtures of the various
         compounds, and apparently  have similar  chemical,  biological,  and lexicological
         properties.

     B.  For chemicals that would ionize significantly in most natural bodies of water, such as
         inorganic salts, organic  acids and phenols,  all forms  that would be  in chemical
         equilibrium  should  usually be  considered one substance.  For  metals, each different
         valence and each different covalently bonded organometallic compound should usually
         be considered a separate substance.

     C.  The definition of the substance may also need to take into account the analytical chemistry
         and fate of the substance.

II.  Collect and Review Available Data

     A. Collect all available data on the substance concerning

         1.  toxicity to, and bioaccummulation by, aquatic animals and plants

         2.   FDA action levels

         3.   chronic feeding studies with wildlife
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     B.  Discard all data that are not available in  hard copy (publication, manuscript,  letter,
        memorandum, etc.) with enough supporting information to indicate that acceptable test
        procedures were used and that the results are reliable. Do not assume that all published
        data are acceptable.

     C.  Discard questionable data. For example, discard data from  tests for which no control
        treatment existed, in which too many organisms in the control treatment died or showed
        signs of stress or disease, or in which distilled or deionized water was used as the dilution
        water  for aquatic  organisms. Discard data on formulated mixtures and emulsifiable
        concentrates  of the substance of concern, but not necessarily data on technical  grade
        material.

     D.  Do not use data obtained using

        1.  Brine shrimp, because they usually only occur naturally in water with salinity greater
            than 35 g/kg.

        2.  Species that do not have reproducing wild populations resident in — but not
            necessarily native to — North America. Resident North American species of fishes are
            defined as those listed in "A List of Common and Scientific Names of Fishes from the
            United States and Canada," 3rd ed., Special Publication  No. 6, American Fisheries
            Society, Washington, D.C., 1970. Data obtained with non-resident species can be used
            to  indicate relationships and possible  problem areas, but  cannot be used in the
            derivation of criteria.

        3.  Organisms that  were previously  exposed to significant  concentrations of the test
            material or other pollutants.

III.  Minimum Data Base

     A. A minimum amount of data should be available to help ensure that each of the four major
        kinds of possible adverse effects receives some consideration. Results of acute and chronic
        toxicity tests with a reasonable number and variety of aquatic animals are necessary so
        that data available  for tested species  can be  considered a useful  indication  of the
        sensitivities of the numerous untested species. The requirements concerning  toxicity to
        aquatic plants are less stringent because procedures for conducting tests with plants are
        not as well developed and the interpretation of the results is more questionable. Data
        concerning bioconcentration by aquatic organisms can only be used if other relevant data
        are available.

     B.  To derive a criterion for freshwater aquatic life, the following should be available:

        1.  Acute tests (see section IV) with freshwater animals in at least eight different families
            provided that of the  eight species at least one
            •  Is a salmonid fish
            •  Is a non-salmonid fish
            •  Is a planktonic crustacean
            •  Is a benthic crustacean
            •  Is a benthic insect
            •  Of the benthic species is a detritivore

        2.  Acute-chronic ratios (see  section  VI) for at least three species of aquatic animals
            provided that of the  three species at least one is
            •  A fish
            •  An invertebrate
            •  A freshwater species (the other two may be saltwater species)


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        3.   At least one test with a freshwater alga or a chronic test with a freshwater vascular
            plant (see section VIII). If plants are among the aquatic organisms that are most
            sensitive to the substance, tests with more than one species should be available.

        4.   At least one acceptable bioconcentration factor determined with an aquatic animal
            species, if a maximum permissible tissue concentration is available (see section IX).

    C.  To derive a criterion for saltwater aquatic life, the following should be available:

        1.   Acute tests (see section IV) with saltwater animals in at least eight different families
            provided that of the eight species
            •  At least two different fish families are included
            •  At least five different invertebrate families are included
            •  Either the Mysidae or Penaeidae family or both are included
            •  At least one of the invertebrate families is in a phylum other than Arthropoda

        2.   Acute-chronic ratios (see  section VI) for at least three species of aquatic animals
            provided that of the three species at least one is
            •  A fish
            •  An invertebrate
            •  A saltwater species (the other two may be freshwater species)

        3.   At least one test with a saltwater vascular plant (see section VIII). If plants are among
            the  aquatic organisms most sensitive to the substance, tests with  more than one
            species should be available.

        4.   At least  one acceptable bioconcentration factor determined with an aquatic animal
            species, if a maximum permissible tissue concentration is available (see section IX).

    D.  If  all  the requirements of the  minimum data base are met, a criterion can usually be
        derived, except in special cases. For example, a criterion might not be possible if the
        acute-chronic ratios vary greatly with no apparent pattern. Also, if a criterion is to be
        related  to a water quality characteristic (see sections V and VII), more data will be
        necessary.
            Similarly, if the minimum  data requirements are not satisfied, generally a criterion
        should not be derived, except in special cases. One such special case would be when less
        than the minimum amount of acute and chronic data are available, but the available data
        clearly indicate that the Final Residue Value would be substantially lower then either the
        Final Chronic Value or the Final Plant Value.

IV.  Final Acute Value

     A.  Appropriate measures of the  acute (short-term)  toxiciry of the substance to various
        species of aquatic animals are used to calculate  the Final Acute Value, If acute values are
        available for fewer than 20 species, the Final Acute Value probably should be lower than
        the lowest value. On the other hand, if acute values are available for more than 20 species,
        the Final Acute Value probably should be higher than the lowest value, unless the most
        sensitive species is an important one. Although the procedure used to calculate the Final
        Acute Value has some limitations, it apparently is the best of the procedures currently
        available.

     B.  Acute toxicity tests should be conducted using procedures such as those described in

        1.  ASTM Standard E 729-80,  Practice for Conducting Acute Toxicity Tests with Fishes,
            Macroinvertebrates, and Amphibians. American Society for Testing and Materials,
            1916 Race Street, Philadelphia, PA 19103.
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    2.  ASTM Standard E 724-80, Practice for Conducting Static Acute Toxicity Tests with
       Larvae  of Four Species  of Bivalve Molluscs. American Society for  Testing and
       Materials, 1916 Race Street, Philadelphia, PA 19103.

C.  Results of acute tests in which food was added to the test solutions should not be used,
    because this may unnecessarily affect the results of the test.

D.  Results of acute tests conducted with embryos should not be used (but see section IV.E.2),
    because this is often an insensitive life stage.

E.  Acute values should be based on endpoints and lengths of exposure appropriate to the life
    stage of the species tested. Therefore, only the following kinds of data on acute toxicity to
    aquatic animals should be used:

    1.  48-hour EC50 values based  on immobilization  and 48-hour  LC50 values  for
       first-instar (less than 24 hours old) daphnids and other cladocerans, and second- or
       third-instar midge larvae.

    2.  48- to 96-hour EC50 values based on incomplete shell development and 48- to 96-hour
       LC50 values for embryos and larvae of barnacles, bivalve molluscs (clams, mussels,
       oysters, and scallops), sea urchins, lobsters, crabs, shrimps, and abalones.

    3.  96-hour EC50 values based on decreased shell deposition for oysters.

    4.  96-hour EC50  values on immobilization or loss of equilibrium or both  and 96-hour
       LC50 values for aquatic animals, except for cladocerans, midges, and animals whose
       behavior or physiology allows them to avoid exposure to toxicant or for whom the
       acute adverse effect of the exposure cannot be adequately measured. Such freshwater
       and saltwater animals include air-breathing molluscs, unionid  clams, operculate
       snails, and bivalve molluscs, except for some species that cannot "close up" and thus
       prevent exposure to toxicant, such as the bay scallop (Argopecten irradians).

F.  For the use of LC50 or EC50 values for durations shorter and longer than those listed
    above, see section X.

G.  If the acute toxicity of the substance to aquatic animals has been  shown to be related to a
    water quality characteristic such as hardness for freshwater  organisms or salinity for
    saltwater organisms, a Final Acute Equation should be derived based on that  water
    quality characteristic. Go to section V.

H.  If the acute toxicity of the substance has not been adequately shown to be related to a
    water quality characteristic, for each species for which at least one acute value is available,
    calculate the geometric mean of the results of all flow-through tests in which the toxicant
    concentrations were measured. For a species for which no such result  is available,
    calculate the geometric mean of all available acute values — i.e., results of flow-through
    tests in which the toxicant concentrations were not measured and  results  of static and
    renewal tests based on initial total toxicant concentrations.
     NOTE: The geometric mean of N numbers is obtained by taking the Nth root of the product of
     N numbers. Alternatively, the geometric mean can be calculated by adding the logarithms of
     the N numbers, dividing the sum by N, and taking the antilog of the quotient. The geometric
     mean of two numbers can also be calculated  as the square root of the product  of the two
     numbers. The geometric mean of one number is that number. Either natural (base e) or
     common (base 10) logarithms  can be used to calculate geometric means as long as they are
     used consistently within each  set of data — i.e., the  antilog used must match the logarithm
     used.

I.  Count the number = N of species for which a species mean acute value is available.

J.  Order the species mean acute values from low to high. Take the common logarithms of the
    N values (log mean values).

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    K.  The intervals (cell widths)  for the lower cumulative proportion calculations are 0.11
        common log units apart, starting from the lowest log value.  The value of 0.11 is an
        estimate of average precision and was calculated from replicate species acute values.

    L.  Starting with the lowest log mean value, separate the N values into intervals (or cells)
        calculated in step IV.K.

    M. Calculate cumulative proportions for each non-empty interval by summing the number
        of values in the present and all lower intervals and dividing by N. These calculations only
        need to be done for the first three non-empty intervals (or cells).

    N. Calculate the arithmetic mean of the log mean values for each of the three intervals.

    O. Using the two interval mean acute values and cumulative proportions closest to 0.05,
        linearly extrapolate or interpolate to the 0.05 log concentration.  The Final Acute Value is
        the antilog of the 0.05 concentration.
           In other words, where
              Prop (1) and cone (1) are the cumulative proportion and mean log value  for the
              lowest non-empty interval.
              Prop (2) and cone (2) are the cumulative proportion and mean log value  for the
              second lowest non-empty interval.
              A = Slope of the cumulative proportions
              B = The 0.05 log value
           then:
              A = [0.05 - Prop (1)] / [Prop(2) - Prop (1)]
              B = cone (1) + A [cone (2) - cone (1)]
              Final Acute Value = 105

    P.  If for an important species, such as a recreationally or commercially important species, the
        geometric mean of the acute  values  from flow-through tests in which the toxicant
        concentrations were measured is lower than the Final Acute Value, then that geometric
        mean should be used as the Final Acute Value.

    Q. Go to section VI.

V.  Final Acute Equation

     A. When enough data are available to show that acute  toxicity to two or more species is
        similarly affected by a water quality characteristic, this effect can be taken into account as
        described below. Pooled regression analysis should produce similar results, although data
        available for individual species would be weighted differently.

    B. For each species for which comparable acute toxicity values are available at two or more
        different values of a water quality characteristic which apparently affects toxicity, perform
        a least squares regression of the natural logarithms of the acute toxicity values on the
        natural logarithms of the values of the water quality characteristic. Natural logarithms
        (logarithms to the base e, denoted as In) are used herein merely because they are easier to
        use on some hand calculators and computers than common logarithms (logarithms to the
        base 10). Consistent use of either will produce the same result. No transformation or a
        different transformation may be used if it fits the data better, but  appropriate changes will
        be necessary throughout this section.

     C. Determine whether or not each acute slope is meaningful, taking into account the range
        and number of values of the water characteristic tested. For example, a slope based on
        four data points may be of limited value if it is based  only on data for a narrow range of
        values of the water quality characteristic. On the other hand, a  slope based on only two
        data points may be meaningful if it is consistent with other information and if the two

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        points cover a broad enough range of the water quality characteristic. If meaningful
        slopes are not available for at least two species, or if the available slopes are not similar,
        return to section IV.H., using the results of tests conducted under conditions and in water
        similar to those commonly used for toxicity tests with the species.

     D. Calculate the mean acute slope (V) as the arithmetic average of all the meaningful acute
        slopes for individual species.

     E.  For each species calculate the geometric mean (W) of the acute toxicity values and the
        geometric mean (X) of the related values of the water quality characteristics.

     F.  For each species calculate the logarithmic intercept (Y) using the equation:
                                    Y = in W - V(ln X).

     G. For each species calculate the species mean acute intercept as the antilog of Y.

     H. Obtain the Final Acute Intercept by using the procedure described in section IV.I-O, except
        insert "Intercept" for "Value."

     I.  If for an important species, such as a recreationally or commercially important species, the
        intercept  calculated only from results  of  flow-through tests in which  the toxicant
        concentrations were measured is lower than the Final Acute Intercept, then that intercept
        should be used as the Final Acute Intercept.

     J.  The Final Acute Equation is written as
                              (v[ln(water quality characteristic)+ln z)

        where
          V = mean acute slope
          Z = Final Acute Intercept.

VI.  Final Chronic Value

     A. The Final Chronic Value can be calculated in the same manner as the Final Acute Value or
        by dividing the Final Acute Value by the Final Acute Chronic Ratio, depending on the data
        available. In some cases it will not be possible to calculate a Final Chronic Value.

     B. Use only the results of flow-through (except renewal is acceptable for daphnids) chronic
        tests in which the concentrations of toxicant in the test solutions were measured.

     C. Do not use the results of any chronic test  in which survival, growth,  or reproduction
        among the controls was unacceptably low.

     D. Chronic values should be based on endpoints and lengths of exposure appropriate to the
        species. Therefore, only the results of the following kinds of chronic toxicity tests should
        be used:

        1.  Life-cycle toxicity tests consisting  of exposures  of  each  of  several  groups  of
            individuals of a species to a different concentration of the toxicant throughout a life
            cycle. To ensure that all life stages and life processes are exposed, the test should begin
            with embryos or newly hatched young less than 48 hours old (less than 24 hours old
            for daphnids), continue through maturation and reproduction, and with fish should
            end  not less than 24  days  (90 days for salmonids) after  the hatching of the next
            generation. For fish, data should be obtained and analyzed on survival and growth of
            adults and young, maturation of males and females, embryos spawned per female,
            embryo viability  (salmonids only) and hatchability. For daphnids, data should be
            obtained and analyzed on survival and young per female.


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       2.  Partial life-cycle toxicity tests consisting of exposures of each of several groups of
          individuals of a species of fish to a different concentration of the toxicant through
          most portions of a life cycle. Partial life-cycle tests are conducted with fish species that
          require more than a year to reach sexual maturity, so that the test can be completed in
          less than 15 months, but still expose all major life stages to the toxicant. Exposure to
          the toxicant begins with immature juveniles at least 2 months prior to active gonad
          development, continues through maturation and reproduction, and ends not less
          than 24 days (90 days for salmonids) after the hatching of the next generation. Data
          should be obtained and analyzed on survival and  growth  of adults and young,
          maturation of males and females, embryos spawned per female, embryo viability
          (salmonids only), and hatchability.

       3.  Early-life-stage toxicity tests consisting of 28-  to 32-days  (60 days post-hatch for
          salmonids) exposures of the  early life stages of a species of fish from shortly after
          fertilization through embryonic, larval, and early juvenile development. Data should
          be obtained and analyzed on survival and growth.

   E.  Do not use the results of an early-life-stage test if results of a life-cycle or partial life-cycle
       test with the same species are available.

   F.  A chronic value is obtained by calculating the geometric mean of the lower and upper
       chronic limits from a chronic test. A lower chronic limit is the highest tested concentration

       1.  in an acceptable chronic test,

       2.  which did not cause the occurrence (which was statistically significantly different
          from the control at p = 0.05) of a specified adverse effect, and

       3.  below which no tested concentration caused such an occurrence.

       An upper chronic limit is the lowest tested concentration

       1.  in an acceptable chronic test,

       2.  which did cause the occurrence (which was statistically significantly different from
          the control at p = 0.05) of a specified adverse effect, and

       3.  above which all tested concentrations caused such an occurrence.
           NOTE: Various authors have used a variety of terms of definitions to interpret the results
           of chronic tests, so reported results should be reviewed carefully.

   G.  If the chronic toxicity of the substance to aquatic animals has been adequately shown to be
       related to a water quality characteristic  such  as hardness for freshwater organisms  or
       salinity for saltwater organisms, a Final Chronic Equation should be derived based on that
       water quality characteristic. Go to section VII.

   H.  If chronic values are available for eight species as described in section III. B.I or C.i, a
       species' mean chronic value should be calculated for each species for which at least one
       chronic value is available by calculating the geometric mean of all the chronic values for
       the species. The Final Chronic Value should then be obtained  using the procedures
       described in section IV.I-O. Then go to section VI.M.

   I.  For each chronic value for which at least one appropriate acute value is available, calculate
       an acute-chronic ratio, using for the numerator the arithmetic average of the results of all
       standard flow-through acute tests in which the concentrations were measured and which
       are from the same study as the chronic test. If such an acute test is not available, use for the
       numerator the results of a standard acute test performed at the same laboratory with the
       same species, toxicant, and dilution water. If no such acute test is available, use the species
       mean acute value for the numerator.
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             NOTE:  If the acute toxicity or chronic toxicity or both of the substance have been
             adequately shown to be related to a water quality characteristic, the numerator and the
             denominator must be based on tests performed in the same water.

     J.  For each species, calculate the species mean acute-chronic ratio as the geometric mean of
        all the acute-chronic ratios available for that species.

     K. For some substances  the species mean acute-chronic ratio seems to be the same for all
        species; but for other substances the ratio seems to increase as the species mean acute
        value increases. Thus the Final Acute-Chronic Ratio can be obtained in two ways,
        depending on the data available.

        1.  If no major trend is apparent and the acute-chronic ratios for a number of species are
            within a factor of 10, the final Acute-Chronic Ratio  should be calculated as the
            geometric mean  of all the species' mean acute-chronic ratios available for  both
            freshwater and saltwater species.

        2.  If the species' mean acute-chronic ratio seems to increase as the species' mean acute
            value increases, the value of the acute-chronic ratio for species whose acute values are
            close to the Final Acute Value should be chosen as the Final Acute-Chronic Ratio.

     L. Calculate the Final Chronic Value by  dividing the  Final Acute  Value by the Final
        Acute-Chronic Ratio.

     M. If the species mean chronic value of  an important species, such as a commercially or
        recreationally important species, is lower than the Final Chronic Value, then that species'
        mean chronic value should be used as the Final Chronic Value.

     N. Go to section VIII.

VII. Final Chronic Equation

     A. For each species for which comparable chronic toxicity values are available at two or more
        different values of a water quality characteristic that apparently affects chronic toxicity,
        perform a least squares regression of the natural logarithms of the chronic toxicity values
        on the natural logarithms of the water quality characteristic values. No transformation or
        a different transformation may be used if it fits the data better, but appropriate changes
        will be necessary throughout this section. It is probably preferable, but not necessary, to
        use the same transformation that was used with the acute values in section V.

     B. Determine whether or not each chronic slope is meaningful, taking into account the range
        and number of values of the water quality  characteristic  tested. For example, a slope
        based on four data points may be of limited value if it is based only on data for a narrow
        range of values of the water quality characteristic. On the other hand, a slope based on
        only two data points  may be meaningful if it is consistent with other information and if
        the  two points cover a broad enough  range of the water quality characteristic. If a
        meaningful chronic slope is not available for at least one species, return to section VI.H.

     C. Calculate the mean chronic slope (L) as the arithmetic average of all the meaningful
        chronic slopes for individual species.

     D. For each species calculate the geometric mean (M) of the toxicity values and the geometric
        mean (P) of the related values of the water quality characteristic.

     E. For each species calculate the logarithmic intercept (Q) using the equation:

                                    Q = lnM-L(lnP).

     F. For each species calculate a species mean chronic intercept as the antilog of Q.


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     G. Obtain the Final Chronic Intercept by using the procedure described in section IV. I-O,
        except insert "Intercept" for "Value."

     H. If the species mean chronic intercept of an important species, such as a commercially or
        recreationally important species, is lower than the Final Chronic Intercept, then that
        species' mean chronic intercept should be used as the Final Chronic Intercept.

     I.  The Final Chronic Equation is written as
                             (L[ln (water quality characteristic)] + In R)

        where
          L = mean chronic slope
          R = Final Chronic Intercept.

VIII.Final Plant Value

     A. Appropriate measures of the  toxicity of the substance to aquatic plants are used to
        compare the relative sensitivities of aquatic plants and animals.

     B. A value is a concentration that decreased growth (as measured by  dry weight,
        chlorophyll, etc.) in a 96-hour or longer test with an alga or in a chronic test with an aquatic
        vascular plant.

     C. Obtain the Final Plant Value by selecting the lowest plant value from a test in which the
        toxicant concentrations were measured.

IX.  Final Residue Value

     A. The Final Residue Value is derived in order to

        1.  Prevent commercially or recreationally important aquatic organisms from exceeding
            relevant FDA action levels, and

        2.  Protect  wildlife, including fishes  and  birds, that eat aquatic  organisms  from
            demonstrated adverse effects.

        A residue value is calculated by dividing a maximum permissible tissue concentration
        by an appropriate bioconcentration factor (BCF), where the BCF is the quotient of the
        concentration of a substance in all or part of an aquatic organism divided by the
        concentration in water to which the organism has been exposed. A maximum
        permissible tissues concentration is either

        1.  An action level from the FDA Administrative Guidelines Manual for fish oil or for the
            edible portion of fish or shellfish, or

        2.  A maximum acceptable dietary intake based on observations on survival, growth, or
            reproduction in a chronic wildlife feeding study.

        If no maximum permissible tissue concentration is available, go to section X because no
        Final Residue Value can be derived.

     B. Bioconcentration factor

        1.  A BCF determined in a laboratory test should be used only if it was calculated based
            on measured concentrations of the substance in the test solution and was based on an
            exposure that continued until either steady-state or 28-days was reached. Steady-state
            is reached when the BCF does not change significantly over a period of time, such as
            two days or 16 percent of the length of the exposure, whichever is longer. If a
            steady-state BCF is not available for a species, the available  BCF for the longest
            exposure over 28 days should be used for that species.

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   2.  A BCF from a  field  exposure should be used only when it is known  that the
       concentration of the substance was reasonably constant for a long enough period of
       time over the range of territory inhabited by the organisms.

   3.  If BCF values from field exposures are consistently lower or higher than those from
       laboratory exposures, then only those values from field exposures should be used if
       possible.

   4.  A BCF should  be calculated based on the  concentration of the substance and its
       metabolites, which are structurally similar and are not much more soluble  in water
       than the parent compound, in appropriate tissue and should be corrected for the
       concentration in the organisms at the beginning of the test.

   5.  A BCF value obtained from a laboratory or field exposure that caused an observable
       adverse effect on the test organism may be used only if it is similar to that obtained
       with unaffected organisms at lower concentrations in the same test.

   6.  Whenever a BCF is determined for a lipid-soluble substance, the percent lipids should
       also be determined in  the tissue for which the BCF was calculated.

C. A BCF calculated using dry tissue weights must be converted to a wet tissue weight basis
   by multiplying the dry weight BCF value by 0.1 for plankton and  by 0.2 for individual
   species of fishes and invertebrates.

D. If enough pertinent data exist, several residue values can be calculated by dividing
   maximum permissible tissue concentrations by appropriate BCF values.

   1.  For each available maximum acceptable dietary intake derived from a chronic feeding
       study with wildlife, including birds and aquatic organisms, the appropriate BCF is
       based on the whole body of aquatic species that constitute or represent a major
       portion of the diet of the tested wildlife species.

   2.  For an FDA action level, the appropriate BCF is the highest geometric mean species
       BCF for the edible portion (muscle for decapods, muscle with or without skin for
       fishes, adductor muscle for scallops and total living tissue for other bivalve molluscs)
       of a consumed species. The highest species BCF is used because  FDA action levels are
       applied on a species-by-species basis.

E. For lipid-soluble substances, it may be possible to calculate additional residue values.
   Because steady-state BCF values for a lipid-soluble chemical seem  to be proportional to
   percent lipids from one tissue to another and from one species to another, extrapolations
   can be made from tested  tissues or species to untested tissues or species on the basis of
   percent lipids.

   1.  For each BCF where the percent lipids is known for the same tissue which the BCF was
       measured, the BCF should be normalized to a 1 percent lipid basis by dividing the
       BCF by the percent lipids. This adjustment to a 1 percent lipid basis makes all the
       measured BCF values comparable, regardless of the  species or tissue for which the
       BCF is measured.

   2.  Calculate  the  geometric  mean normalized BCF.  Data  for  both  saltwater and
       freshwater species can be  used to determine the mean normalized BCF, because the
       normalized BCF seems to be about the same for both kinds of organisms.

   3.  Residue values  can then be calculated by dividing the maximum permissible tissue
       concentrations  by the mean normalized  BCF and by a percent lipids value
       appropriate to the maximum permissible tissue concentration.

            _  . .   ...       (maximum permissible tissue concentration)
            Residue Value	•        ,.r ^n^n	,...,,
                         (mean normalized BCF) (appropriate percent lipids)

       a. For an FDA action level for fish oil, the appropriate percent lipids value is 100.

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            b. For an FDA action level for fish, the appropriate percent lipids value is 15 for
              freshwater criteria and 16 for saltwater criteria because FDA action levels are
              applied species-by-species to commonly consumed species. The edible portion of
              the freshwater lake trout averages about 15 percent lipids, and the edible portion
              of the saltwater Atlantic herring averages about 16 percent lipids (Sidwell, V.D., et
              al. 1974 Composition of the Edible Portion of Raw (Fresh or Frozen) Crustaceans,
              Finfish, and Mollusks. I. Protein, Fat, Moisture, Ash, Carbohydrate, Energy Value,
              and Cholesterol, Marine Fisheries Review 36:21-35).
            c. For a maximum acceptable  dietary intake derived from a chronic feeding study
              with wildlife, the appropriate percent lipids is the percent lipids of an aquatic
              species or group of aquatic species that constitutes a major portion of the diet of
              the wildlife species.

        The Final Residue Value is obtained by selecting the lowest of the available residue values.
        In many cases the Final Residue Value will not be low enough. For  example, a residue
        value calculated from an FDA action level would result in an average concentration in the
        edible portion of a fatty species that is at the action level. On the average half, of the
        individuals of the species would have concentrations above the FDA action level. Also,
        the results of many chronic feeding studies are concentrations that cause adverse effects.

X.   Other Data
        Pertinent information  that  could  not be  used in earlier sections may be  available
        concerning adverse effects on aquatic organisms and their uses. The most important of
        these are data on flavor impairment, reduction in survival, growth,  or reproduction, or
        any other adverse effect that has been shown to be biologically significant. Especially
        important are data for species for which no other data are available. Data from behavioral,
        microcosm, field, and physiological studies may also be available.

XI.  Criterion

     A. The criterion consists of two concentrations, one  that should not be exceeded on the
        average in a 24-hour period and one that should not be exceeded at any time during the
        24-hour  period.  This  two-number criterion is  intended to identify water quality
        conditions that should  protect aquatic life and its uses from acute and  chronic adverse
        effects of both cumulative and noncumulative substances without being as restrictive as a
        one-number criterion would have to be to provide the same degree of protection.

     B. The maximum concentration is the Final Acute Value or is obtained from the Final Acute
        Equation.

     C. The 24-hour average concentration is obtained from the Final Chronic  Value, the Final
        Plant Value, and the Final Residue Value by selecting the lowest available value, unless
        other data (see section X) from tests in which the toxicant concentrations were measured
        show  that a lower value  should be used. If toxicity is related  to a water quality
        characteristic, the 24-hour average concentration is obtained from the Final Chronic
        Equation, the Final Plant Value, and the Final Residue Value by selecting the one that
        results in the lowest concentrations in the normal range of the water quality characteristic,
        unless other data (see section X) from tests in which the toxicant concentrations were
        measured show that a lower value should be used.

     D. The criterion is (the 24-hour average concentration) as a 24-hour average and the
        concentration should not exceed (the maximum concentration) at any time.

XII. Review

     A. On the basis of all available pertinent laboratory and field information,  determine if the
        criterion is consistent with sound scientific evidence. If it is not, another criterion, either
        higher or lower, should be derived using appropriate modifications of the Guidelines.
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                                 APPENDIX C

                      Derivation of the 1980
                     Human Health  Criteria
                     (Excerpted from 45 PR. 79347, November 28,1980)
   NOTE: The Agency is currently updating the 1980 Methodology for Deriving Human Health Criteria. The
   Agency recognizes that the underlying science has advanced significantly during the past 12 years in
   technical areas such as cancer and noncancer risk, mutagenitiry, male and female reproductive and
   developmental effects, and exposure assessment. Furthermore, state standards developed from the
   original criteria have been challenged technically with appropriate justification in some cases. Also, the
   Agency recognizes the  need  to reconsider some basic assumptions as a result of programmatic
   inconsistencies that have developed within the Office of Water. Examples of these assumptions are
   designation of Group C chemicals, rate values for human consumption of fish and shellfish and of
   drinking water, and relative source contributions.

   To  provide a state-of-the-science approach to revising the 1980 methodology, the Agency first
   developed an issues paper that presented details of the 1980 methodology, discussed its deficiencies,
   and proposed revisions to improve this process. The issues paper was then sent for review and
   comment to  experts at U.S. EPA headquarters, regions, and laboratories; other U.S. governmental
   agencies, such as NIEHS and CDC; state health organizations; Canadian health agencies; academia;
   environmental groups; industry; and consulting organizations. A workshop that discussed these issues
   was held in Bethesda, Maryland, on September 13-16,1992, with more than 100 experts participating.
   The workshop's conclusions are contained in the document entitled Revision of Methodology for Deriving
   National Ambient Water Quality Criteria for the Protection of Human Health: Report of Workshop and EPA's
   Preliminary Recommendation for Revision, dated January 8,1993. The document is available by calling the
   EPA Human Risk Assessment Branch at (202) 260-7571.

   The Agency anticipates proposing a revised methodology in late 1994, with a final revision presented in
   the Federal Register in late 1995.
Guidelines and Methodology Used in the Preparation of Health Effect
Assessment Chapters of the Consent Decree Water Criteria Documents

I.    Objective
     The objective of the health effect assessment chapters of the ambient water criteria documents
     is to estimate ambient water concentrations that do not represent a significant risk to the
     public. These assessments should constitute a review of all relevant information on individual
     chemicals or chemical classes in order to derive criteria that represent, in the case of suspect or
     proven  carcinogens, various levels of  incremental cancer risk, or, in  the case of other
     pollutants, estimates of no-effect levels.
        Ideally, ambient water quality criteria should represent levels for compounds in ambient
     water that do not pose a  hazard to  the human population. However, in  any realistic
     assessment of human health hazard, a fundamental distinction must be made between
     absolute safety and recognizing some risk. Criteria for absolute safety would have to be based
     on detailed knowledge of dose-response relationships in humans, including all sources of
     chemical exposure, the types of toxic effects elicited, the existence of thresholds for the toxic
     effects, the significance of toxicant interactions, and the variances of sensitivities and exposure
     levels within the human population. In practice, such absolute criteria cannot be established
     because  of deficiencies in  both  the available  data  and the means of interpreting this
     information. Consequently, the individual human health effects chapters propose criteria that

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     minimize or specify the potential risk of adverse human effects due to substances in ambient
     water. Potential social or economic costs and benefits are not considered in the formulation of
     the criteria.

II.   Types of Criteria
     Ambient  water  quality  criteria  are based  on  three  types  of  biological endpoints:
     carcinogenicity, toxicity (i.e., all adverse effects other than cancer), and organoleptic effects.
        For the purpose of deriving ambient water quality criteria, carcinogenicity is regarded as a
     non-threshold phenomenon.  Using  this assumption,  "safe"  or "no  effect"  levels  for
     carcinogens cannot be established because even extremely small doses must be assumed to
     elicit a finite increase in the incidence of the response. Consequently, water quality criteria for
     carcinogens are  presented as  a  range  of  pollutant  concentrations  associated  with
     corresponding incremental risks.
        For compounds that do not manifest any apparent carcinogenic effect,  the threshold
     assumption is used in deriving a criterion. This assumption is based on the premise that a
     physiological reserve capacity exists within the organism that is thought to be depleted before
     clinical disease ensues. Alternatively, the rate of damage will likely be insignificant over the
     life  span  of  the organism.  Thus,  ambient water quality  criteria  are  derived  for
     non-carcinogenic chemicals, and presumably result in no observable-adverse-affect levels
     (NOAELs) in the exposed human population.
        In some instances,  criteria are based on organoleptic characteristics (i.e., thresholds for
     taste or odor). Such criteria are established when insufficient information is available on
     toxicologic effects or when the estimate of the level of the pollutant in ambient water based on
     organoleptic effects is lower than the level calculated from toxicologic data. Criteria based
     solely on organoleptic effects do not necessarily represent approximations of acceptable risk
     levels for human health.
        Several ambient water quality criteria documents deal with  classes of compounds that
     include chemicals exhibiting varying  degrees of structural similarity. Because prediction of
     biological effects  based solely on structural  parameters is difficult,  the  derivation of
     compound-specific criteria is preferable to a class criterion. A compound-specific criterion is
     defined as a  level derived from data on each individual subject compound that does not
     represent  a  significant risk to  the public.  For some  chemical  classes, however,  a
     compound-specific criterion cannot be derived for each member of a class. In such instances, it
     is sometimes justifiable to derive a class criterion in which available data on one member of a
     class may be used to estimate criteria for other chemicals of the class because a sufficient data
     base is not available for those compounds.
        For some chemicals and chemical classes, the data base was judged to be insufficient for the
     derivation of a criterion. In those cases, deficiencies in the available information are detailed.

 HI.  Approach
     The human health effects chapters attempt to summarize ajl information on the individual
     chemicals or classes of chemicals that might be useful in the risk assessment process to develop
     water quality criteria. Although primary emphasis is placed on identifying epidemiologic and
     toxicologic data, these assessments typically contain discussions on four topics: existing levels
     of human exposure, pharmacokinetics, toxic effects, and criterion formulation.
        For all documents,  an attempt is made to include the known relevant information. Review
     articles and reports are often used in the process of data evaluation and synthesis. Scientific
     judgment is exercised in the review and evaluation of the data in each document and in the
     identification of the adverse effects against which protective criteria are sought. In addition,
     each  of these documents is reviewed by a peer committee of scientists familiar with the
     specific compound(s). These work groups evaluate the  quality of the available data, the
     completeness of the data summary, and the validity of the derived criterion.
        In the analysis and organization of the data, an attempt is made to be consistent in the
     format and application of acceptable scientific principles. Evaluation procedures used in the

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hazard assessment process follow  the principles outlined by the National Academy of
Sciences in Drinking Water and Health (1977) and the guidelines of the Carcinogen Assessment
Group of the U.S. EPA.

A.  Exposure
       The exposure section of the health effects chapters reviews known information on
    current levels of human exposure to the individual pollutant from all sources. Much of the
    data was obtained from monitoring studies of air, water, food, soil, and human or animal
    tissue residues. The major purpose of this section is to provide background information
    on the contribution of water exposure relative to  all other sources. Consequently, the
    exposure section includes subsections reviewing different routes of exposure, including
    water and food ingestion, inhalation, and dermal contact.
       Information on exposure can be valuable in developing and assessing a water quality
    criterion. In these documents, exposure from consumption of contaminated water and
    contaminated fish and shellfish products is used in  criterion formulation. Data for all
    modes of exposure are useful in relating total intake to the expected contribution from
    contaminated water, fish, and shellfish. In addition, information for all routes of exposure,
    not limited to drinking water and fish and shellfish ingestion, can be used to justify or
    assess the feasibility of the formulation of criteria for ambient water.
       The  use  of fish consumption as an exposure factor requires the quantitation of
    pollutant residues  in  the  edible  portions  of the ingested species.  Accordingly,
    bioconcentration factors (BCFs) are used to relate pollutant residues in aquatic organisms
    to the pollutant concentration in the ambient waters in which they reside.
       To estimate the average per capita intake of  a  pollutant  due to consumption of
    contaminated fish and shellfish, the results of a diet survey were analyzed to calculate the
    average  consumption  of  freshwater and estuarine  fish and  shellfish.  A species is
    considered to be a consumed freshwater or estuarine fish and shellfish species if at some
    stage in its life cycle it is harvested from fresh or estuarine water for human consumption
    in significant quantities.
       Three different procedures are used to estimate the weighted average BCF, depending
    upon the lipid solubility of the chemical and the availability of bioconcentration data.
       For lipid-soluble compounds, the average BCF is calculated from the  weighted
    average percent lipids in the edible portions of consumed freshwater and estuarine fish
    and shellfish, which was calculated from data on consumption of each species and its
    corresponding percent  lipids to be  3  percent. Because  the  steady-state  BCFs for
    lipid-soluble compounds are proportional to percent  lipids, bioconcentration factors for
    fish and shellfish can be adjusted to the average percent lipids for aquatic organisms
    consumed by Americans. For many lipid-soluble pollutants, there exists at least one BCF
    for which the percent lipid value was measured for the tissues for which the BCF is
    determined.
       With 3 percent as the weighted average percent lipids for freshwater and estuarine
    fish and shellfish in the average diets, a BCF, and a corresponding percent lipid value, the
    weighted average bioconcentration factor can be calculated.

       Example:
          Weighted average percent lipids for average diet = 3.0 percent
          Measured BCF of 17 for trichloroethylene with bluegills at 4.8 percent lipids
          Weighted average BCF for average diet equals

             -tit—
        As an estimate, 10.6 is used for the BCF.

       In those cases where an appropriate bioconcentration factor is not available, the
    equation "Log BCF = (0.85 Log P)-  0.70" can be used to estimate the BCF for aquatic
    organisms containing about 7.6 percent lipids from the octanol/water partition coefficient
    P. An adjustment  for percent lipids in the average diet versus 7.6 percent is made in order
    to derive the weighted average bioconcentration factor.
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           For non-lipid-soluble compounds, the available BCFs  for the edible portion  of
        consumed freshwater and  estuarine fish  and shellfish are  weighted  according  to
        consumption factors to determine a weighted BCF representative of the average diet.

    B.  Pharmacokinetics
           This section summarizes the available information on the absorption, distribution,
        metabolism, and elimination of the compound(s) in humans and experimental mammals.
        Conceptually, such  information  is  useful in validation of  inter- and intraspecies
        extrapolations, and in characterizing the modes of toxic actions. Sufficient information on
        the absorption and  excretion in  animals —  together with a knowledge of ambient
        concentrations in water, food, and air — could be useful in estimating body burdens of
        chemicals in the human population. Distribution data that suggest target organs or tissues
        are  desirable for interspecies comparison  techniques. For  derivation of  criteria,
        pharmacokinetic data are essential to estimate equivalent oral doses based on data from
        inhalation or other routes of exposure.

    C.  Effects
           This section summarizes information on biological effects in  both  humans and
        experimental  mammals resulting in  acute, subacute, and chronic toxicity; synergism
        and/or antagonism; teratogenicity, mutagenicity, or carcinogenicity.
           The major goal of this section is to  survey the suitability of the data for use  in
        assessment of hazard and to determine which biological  end-point (i.e., non-threshold,
        threshold, or organoleptic) should be selected for use in criterion formulation.
           Because this section attempts to assess potential human health effects, data on
        documented human effects are thoroughly evaluated. However, several factors inherent
        in human epidemiological studies usually preclude the use of such data in generating
        water quality criteria. These problems, as summarized  by  the National Academy  of
        Sciences, are as follows:
        1.  Epidemiology cannot tell what effects a material will have until  after humans have
           been exposed. One must not conduct what might be hazardous experiments on man.
        2.  If exposure has been ubiquitous, assessing the effects of a material may be impossible
           because no control group is unexposed. Statistics of morbidity obtained before using a
           new material can sometimes be useful; but when latent periods are variable and times
           of introduction and removal of materials overlap, historical data on chronic effects are
           usually unsatisfactory.
        3.  Determining doses in human exposure is usually difficult.
        4.  Usually, it is hard to identify small changes in common effects, which may nonetheless
           be important if the population is large.
        5.  Interactions in a "nature-designed" experiment usually cannot be  controlled.

           Although these  problems often prevent  the  use  of epidemiological data  in
        quantitative risk assessments, qualitative similarities or differences between documented
        effects in humans and observed effects in experimental mammals are  extremely useful in
        testing the validity  of animal-to-man  extrapolations.  Consequently, in each case, an
        attempt is made to identify and utilize both epidemiological and animal dose-response
        data. Criteria derived from such a confirmed data base are  considered  to be reliable.
           The decision to establish a criterion based on a non-threshold model  is made after
        evaluating all available information on carcinogenicity and supportive information on
        mutagenicity. The approach and conditions for the qualitative decision of carcinogenicity
        are outlined in the U.S. EPA Interim Cancer Guidelines (41FR 21402), in a report by Albert,
      .  et al. (1977), and in the Interagency Regulatory Liaison Group (IRLG) guidelines on
        carcinogenic risks (IRLG, 1979).  A  substance that induces a statistically significant
        carcinogenic response in animals is  assumed to have the capacity  to cause cancer  in
        humans. A chemical that has not induced a significant cancer response in humans  or
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   experimental animals is not identified as a carcinogen, even though its metabolites or
   close structural analogues might induce a carcinogenic response or it was shown to be
   mutagenie in an in vitro system.
       Some potential human carcinogens may not be identified by the guidelines given
   above. For example,  compounds that have plausible but weak qualitative evidence of
   carcinogenicity in experimental animal systems (such as data from mouse skin painting or
   strain A mouse pulmonary adenoma) would be included in this category. The derivation
   of a criterion for human consumption from these studies in not valid, regardless of the
   qualitative outcome. In addition, certain compounds (e.g., nickel and beryllium) shown to
   be carcinogenic in humans after inhalation exposure by chemical form have induced, thus
   far, no response in animals or humans via ingesting their soluble salts.
       Nevertheless, nonthreshold criterion is developed for beryllium because tumors have
   been produced in animals at a site removed from the site of administration. In contrast, a
   threshold criterion is recommended for nickel because no evidence exists of tumors at
   distant sites resulting from administration of nickel  solutions by either ingestion or
   injection.
       For those compounds not  reported  to induce carcinogenic effects or for  which
   carcinogenic data are lacking or insufficient, an attempt  is made to  estimate a no-effect
   level. In many respects, the hazard evaluation  from these studies  is similar to that of
   bioassays for carcinogenicity. In order to more closely approximate conditions of human
   exposure, preference is given to chronic studies involving oral exposures in water or diet
   over a significant portion of the  animal life span. Greatest confidence is placed in those
   studies that demonstrate dose-related adverse effects as well as no-effect levels.
       The biological endpoints used to define a no-effect level vary considerably. They may
   range from gross effects — such as mortality — to more subtle biochemical, physiological,
   or pathological changes. Teratogenicity, reproductive impairment, and behavioral effects
   are significant toxic consequences of environmental contamination. In instances  where
   carcinogenic  or other chronic effects  occur at exposure levels  below those causing
   teratogenicity, reproductive impairment, or behavioral effects, the  former are used in
   deriving the criterion. For most of the compounds evaluated thus far, teratogenicity and
   reproductive impairment occur at doses near maximum tolerated levels with dose
   administration schedules well above  estimated  environmental exposure  levels.
   Moreover,  information on behavioral effects, which  could  be  of  significance,  is not
   available for most of the compounds under study. Consequently, most NOAELs derived
   from chronic studies are based either on gross toxic effects or on effects directly related to
   functional impairment or defined pathological lesions.
       For compounds on which adequate chronic toxicity studies are not available, studies
   on acute and subacute toxicity assume greater significance. Acute toxicity studies usually
   involve single exposures at lethal or near lethal doses. Subacute studies often involve
   exposure exceeding 10 percent of the life span of the test organism, (e.g., 90 days for the rat
   with an average life span of 30 months). Such studies are useful in establishing the nature
   of the compound's toxic effects and other parameters of compound toxicity, such as target
   organ  effects, metabolic  behavior,  physiological/biochemical effects,  and patterns of
   retention and tissue distribution. The utility of acute and subacute studies in deriving
   environmentally meaningful NOELs  is  uncertain, although  McNamara (1976)  has
   developed application factors for such derivations.
       In some cases where adequate data are not available from studies utilizing oral routes
   of administration, no-effect levels for oral exposures may be estimated from dermal or
   inhalation studies. Such estimates involve approximations of the total dose administered
   based on assumptions about breathing rates and/or magnitude of absorption.

D. Criterion Rationale
       This section reviews existing standards for the chemical(s), summarizes data on
   current levels of human exposure, attempts to identify special groups at risk, and defines
   the basis for the recommended criterion.

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           Information on existing standards is included primarily for comparison with the
        proposed  water  quality criteria. Some  of the present standards,  such  as  those
        recommended by the Occupational Safety and Health Administration (OSHA) or the
        American Conference of Governmental Industrial Hygienists (ACGIH), are based on
        toxicologic data but are intended as  acceptable levels for  occupational rather  than
        environmental exposure. Other levels, such as  those recommended by the National
        Academy  of Sciences in Drinking Water and Health (1977) or in the U.S. EPA Interim
        Primary Drinking Water Standards, are more closely related to proposed water quality
        criteria. Emphasis is placed on detailing the basis for the existing standards wherever
        possible.
           Summaries of current levels of human exposure, presented in this section, specifically
        address the suitability of the data to derive water quality criteria. The identification of
        special groups at risk,  either because of  geographical or occupational  differences in
        exposure or biological differences in susceptibility to the compound(s), focuses on the
        impact that these groups should have on the development of water quality criteria.
           The basis for the recommended criteria section summarizes  and qualifies all of the
        data used in developing the criteria.

IV.   Guidelines for Criteria Derivation
     The derivation of water quality criteria from laboratory animal toxicity data is essentially a
     two-step procedure. First, a total daily intake for humans must be estimated that establishes
     either a defined level of risk for nonthreshold effects or a noeffect level for threshold effects.
     Secondly, assumptions must be made about the contribution of contaminated water and the
     consumption of fish / shellfish to the total daily intake of the chemical. These estimates are
     then used to establish the tolerable daily intake and consequently the water quality criterion.

     A. Nonthreshold Effects
            After the decision has been made that a compound can potentially cause cancers in
        humans  and  that data exist  that  permit  the  derivation of a criterion, the water
        concentration estimated to cause a lifetime carcinogenic risk of 10"5 is determined. The
        lifetime carcinogenicity risk is the probability that a person would get cancer sometime in
        his or her life assuming continuous exposure to the compound. The water concentration is
        calculated by using the  low-dose extrapolation procedure proposed by Crump (1980).
        This procedure is an improvement on the  multistage low-dose extrapolation procedure
        by Crump, et al. (1977).
            The data used for quantitative estimates are of two types: (1) lifetime animal studies,
        and (2) human studies where excess cancer risk has been associated with exposure to the
        agent. In animal studies it is assumed, unless evidence exists to the contrary, that if a
        carcinogenic response occurs at the dose levels used in the study, then proportionately
        lower responses will also occur at all lower doses, with an incidence determined by the
        extrapolation model discussed below.

        1.  Choice of Model.
               No really solid scientific basis exists for any mathematical extrapolation model
            that relates carcinogen exposure to cancer risks at the extremely low levels of
            concentration present to deal with in evaluating the environmental hazards. For
            practical reasons, such low levels of risk cannot be measured directly either using
            animal experiments or epidemiologic studies. We must, therefore, depend on our
            current understanding of the mechanisms of carcinogenesis for guidance as to
            which risk model to use.
               At the present time, the dominant view of the carcinogenic process involves the
            concept that most agents which cause cancer also cause irreversible damage to
            DNA. This position is reflected by the fact that a very large proportion of agents that
            cause cancer are also mutagenic. The quantal type of biological response
            characteristic of mutagenesis is likely associated with a linear nonthreshold

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   dose-response relationship. Indeed, substantial evidence from mutagenesis studies
   with both ionizing radiation and a wide variety of chemicals suggests that this type
   of dose-response model is the appropriate one to use. This is particularly true at the
   lower end of the dose-response curve; at higher doses, there can be an upward
   curvature, probably reflecting the effects of multistage processes on the mutagenic
   response.
       The linear nonthreshold dose-response relationship is also consistent with the
   relatively few epidemiological studies of cancer responses to specific agents that
   contain enough information to make the evaluation possible (e.g.,
   radiation-induced leukemia, breast and thyroid cancer, skin cancer induced by
   arsenic in drinking water, and liver cancer induced by aflatoxin in the diet). Some  .
   animal experiments are consistent with the linear nonthreshold hypothesis (e.g.,
   liver tumors induced in mice by 2-acetylaminofluorene in the large scale ED0].
   study at the National Center of Toxicological Research, and the initiation stage of
   the two-stage carcinogenesis model in the rat liver and the mouse skin).
       Because it has the best, albeit limited, scientific basis of any of the current
   mathematical extrapolation models, the linear nonthreshold model has been
   adopted as the primary basis for risk extrapolation to low levels of the
   dose-response relationship. The risk assessments made with this model should be
   regarded as conservative, representing the most plausible upper limit for the risk
   (i.e., the true risk is not likely to be higher than the estimate, but it could be smaller).
       The mathematical formulation chosen to describe the linear, nonthreshold
   dose-response relationship at low doses is the improved multistage model
   developed by Crump (1980). This model employs enough arbitrary constants to be
   able to fit almost any monotonically increasing dose-response data, and it
   incorporates a procedure for estimating the largest possible linear slope (in the 95
   percent confidence limit sense) at low extrapolated doses consistent with the data at
   all dose levels of the experiment. For this reason, it may be called a "linearized"
   multistage model.

2.  Procedure of Low-Dose Extrapolation Based on Animal Carcinogenicity Data.
   A. Description of the Extrapolation Model
       Let P(d) represent the lifetime risk (probability) of cancer at dose d. The
       multistage model has the form
          P(d) = 1 - exp [- (q0+ qjd + q2d3+...+qkdk)]
       where:
          qj> O, and i = 0,1,2,.... k
       Equivalently,
          A(d) = 1 - exp [- (qid
       where:

          A(d)	—	   is the extra'risk over backeround rate at dose d.
                  l-l'(o)
       The point estimate of the coefficients q, i = 0,1,2,...,k, and consequently the extra
   risk function A(d) at any given dose d, is calculated by maximizing the likelihood
   function of the data.
       The point estimate and the 95 percent upper confidence limit of the extra risk
   A(d) are calculated by using the computer program GLOBAL 79 developed by
   Crump and Watson (1979). Upper 95 percent confidence limits on the extra risk and
   lower 95 percent confidence limits on the dose producing a  given risk are
   determined from a 95 percent upper confidence limit q^, on parameter q:.
   Whenever qj •« 0, at low doses extra risk A(d) has approximately the form A(d) = q2
   x d. Therefore, ^ x d is a 95 percent upper confidence limit on the extra risk and
   R/ qj* is a 95 percent lower confidence limit on the dose producing an extra risk of
   R. Let L0 be the maximum  value of the log-likelihood function. The upper limit qj*

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           is calculated buy increasing qi to a value qa* such that when the log-likelihood is
           again maximized subject to this fixed value qj* for the linear coefficient, the
           resulting maximum value of the log-likelihood Lj satisfies the equation 2(L0 - Lj) =
           2.70554 where 2.70554 is the cumulative 90 percent point of the chi-square
           distribution with one degree of freedom, which corresponds to a 95 percent upper
           limit (one-sided). This approach of computing the upper confidence limit for the
           extra risk A(d) is an improvement on the Crump, et al. (1977) model. The upper
           confidence limit for the extra risk calculated at low doses is always linear. This is
           conceptually consistent with the linear nonthreshold concept discussed earlier. The
           slope qj* is taken as an upper bound of the potency of the chemical in inducing
           cancer at low doses.
               In fitting the dose-response  model, the number of terms in the polynomial g is
           chosen equal to (h-1), where h is the number of dose groups in the experiment,
           including the control group.
               Whenever the multistage model does not fit the data sufficiently, data at the
           highest dose is deleted and the model is refitted to the rest of the data. This is
           continued until an acceptable fit to the data is obtained. To determine whether or
           not a fit is acceptable, the chi-square statistic:
                2
                           (1 - Ps )
           is calculated, where Nj is the number of animals in the i' dose group, X; is the
           number of animals in the i*  dose group with a tumor response, Pj is the probability
           of a response in the ith dose group estimated by fitting the multistage model to the
           data, and h is the number of remaining groups.
               The fit is determined to be unacceptable whenever chi-square (X  ) is larger than
           the cumulative 99 percent point of the chi-square distribution with f degrees of
           freedom, where f equals the number of dose groups minus the number of non-zero
           multistage coefficients.

        3.  Selection and Form of Data used to Estimate Parameters in the Extrapolation Model.
               For some chemicals, several studies in different animal species, strains, and
           sexes each conducted at several doses and different routes of exposure are available.
           A choice must be made as to which of the data sets from several studies are to be
           used in the model. It is also necessary to correct for metabolism differences between
           species and for differences in absorption via different routes of administration. The
           procedures used in evaluating these data, listed below, are consistent with the
           estimate of a maximum-likely-risk.
           a. The tumor incidence data are separated according to organ sites or tumor types.
             The set data (i.e., dose and tumor incidence) used in the model is set where the
             incidence is statistically significantly higher than the control for at  least one test
             dose level and /or where the tumor incidence rate shows a statistically significant
             trend with respect to dose level. The data set that gives the highest estimate of
             lifetime carcinogenic risk qj* is selected in most cases. However, efforts are made
             to exclude data sets that produce spuriously high risk estimates because of a small
             number of animals.  That is, if two sets of data show a similar dose-response
             relationship and one  has a very small sample size, the set of data that  has the larger
             sample size is selected for calculating the carcinogenic potency.
           b. If there are two more data sets of comparable size that are identical with respect to
             species, strain, sex, and tumor sites, the geometric mean of q^,  estimated from
             each of these  data sets, is  used  for risk assessment. The geometric  mean of
              numbers Av A^..., Am is defined as (Aj x A2 x ... Am)1/m
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c. If sufficient data exist for two or more significant tumor sites in the same study, the
  number of animals with at least one of the specific tumor sites under consideration
  is used as incidence data in the model.
d. Following the suggestion of Mantel and Schneiderman (1975),  we assume that
  mg/surface area/day is an equivalent dose between species.  Since to a close
  approximation the surface area is proportional to the 3^rds power of the weight as
  would be the case for a perfect sphere, the exposure in mg/4^rds power of the
  body weight/day is similarly considered  to be an equivalent  exposure.  In an
  animal experiment, this equivalent dose is computed in the following manner:
      Let:
         Le = duration of experiment
         le=  duration of exposure
         m = average dose per day in mg during administration of the agent
             (i.e., during le)
         W = average weight of the experimental animal.
      -.,,,,.                            U X m
      Then, the lifetime average exposure is   d	7-

      Often exposures are not given in units of mg/ day, and it becomes necessary to
  convert the given exposures to mg/day. For example, in most  feeding studies,
  exposure is expressed as ppm in the diet. In this case the exposure (mg/day) is
  derived by m = ppm x F x r, where  ppm is parts per million of  the carcinogenic
  agent in the diet, F is the weight of the food consumed per day in kgms, and r is the
  absorption fraction.
      In the absence of any data to the contrary, r is assumed to be one. For a uniform
  diet, the weight of the food consumed is proportional to the calories required,
  which, in turn, is proportional to the surface area or the 3^rds power of the weight,
  so that mappm x W  x r or
        m
      As a result, ppm in the diet is often assumed to be an equivalent exposure
  between species. However, this is not justified since the calories/kg of food is
  significantly different in the diet of man vs. laboratory animals, primarily due to
  moisture content differences. Instead, an empirically derived food factor, f=F/W,
  is the fraction of a species body weight that is consumed per day as food. The rates
  are
Species . . . .
Man
Rat 	
Mice . .

. . . . W
. . 70
.... 0.35
. . . . 003

f
0.028
0.06
0.13

  Thus, when the exposure is given as a certain dietary concentration in ppm, the
  exposure in mg/W /3is
        m
      r x
         •xfxW
      When exposure is given in terms of mg/kg/day = m/Wr = s the conversion is
   simply:
        m
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                 When exposure is via inhalation, the calculation of dose can be considered for
             two cases where (1) the carcinogenic agent is either a completely water-soluble gas
             or an aerosol and is absorbed proportionally to the amount of air breathed in, and
             (2) where the carcinogen is a poorly water-soluble gas that reaches an equilibrium
             between the air breathed and  the body compartments. After equilibrium is
             reached, the rate of absorption of these agents is expected to be proportional to
             metabolic rate, which in turn is proportional to the rate of oxygen consumption,
             which in turn is a function of surface area.

    B.  Threshold Effects

        1.  Use of Animal Toxicity Data (oral).
              In developing guidelines for deriving criteria based on noncarcinogenic
           responses, five types of response levels are considered:
              NOEL—No Observed-Effect-Level
              NOAEL—No Observed-Adverse-Effect-Level
              LOEL—Lowest-Observed-Effect-Level
              LOAEL—Lowest-Observed-Adverse-Effect-Level
              PEL—Frank-Effect-Level
              Adverse effects are defined as any effects that result in functional impairment
           and/or pathological lesions which may affect the performance of the whole
           organism or reduce an organism's ability to respond to an additional challenge.
              One of the major problems encountered in considering these concepts regards
           the reporting of "observed effect levels" as contrasted to "observed adverse effect
           levels." The terms "adverse" versus "not adverse" are at times satisfactorily
           defined. But due to increasingly sophisticated testing protocols, more subtle
           responses are being identified, resulting in a need for judgment regarding the exact
           definition of adversity.
              The concepts listed above (NOEL, NOAEL, LOEL, LOAEL) have received much
           attention because they represent landmarks that help define the threshold region in
           specific experiments. Thus, if a single experiment yields a NOEL, a NOAEL, a
           LOAEL, and a clearly defined PEL in closely spaced doses, the threshold region has
           been well defined; such data are very useful for the purpose of deriving a criterion.
           On the other hand, a clearly defined PEL has little utility in establishing criteria
           when it stands alone, because such a level gives no indication how far removed the
           data point is from the threshold region. Similarly, a free-standing NOEL has little
           utility without an indication of its proximity to the LOEL, since a free-standing
           NOEL may be many orders of magnitude below the threshold region.
              Based on the above dose-response classification system, the  following
           guidelines for deriving criteria have been adopted:
           a. A free-standing PEL is unsuitable for the derivation of criteria.
           b. A free-standing NOEL is  unsuitable  for the derivation of criteria.  If multiple
              NOELs are available without additional data on LOELs, NOAELs, or LOAELs, the
              highest NOEL should be used to derive a criterion.
           c. A  NOAEL,  LOEL, OR LOAEL can be  suitable for criteria  derivation.  A
              well-defined NOAEL from a chronic (at least 90-day study) may be used directly,
              applying the appropriate uncertainty  factor. For a LOEL, a judgment needs to be
              made as to whether it actually corresponds to a NOAEL or a LOAEL. In the case of
              a  LOAEL, an additional uncertainty factor  is applied; the magnitude of the
              additional uncertainty factor is judgmental and should lie in the range of 1 to 10.
              Caution  must be  exercised  not  to  substitute "Frank-Effect-Levels"  for
              "Lowest-Observable-Adverse-Effect-Levels."
           d. If for reasonably closely spaced doses only a NOEL and a LOAEL of equal quality
              are available, then the appropriate uncertainty factor is applied to the NOEL.
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       In using this approach, the selection and justification of uncertainty factors are
   critical. The basis definition and guidelines for using uncertainty factors has been
   given by the National Academy of Sciences (1977). "Safety Factor" or "Uncertainty
   Factor" is defined as a number that reflects the degree or amount of uncertainty that
   must be  considered when experimental data in animals are extrapolated to man.
   When  the  quality  and quantity of experimental  data are  satisfactory, a low
   uncertainty factor is used: when data is judged to be inadequate or equivocal, a
   larger  uncertainty factor  is used. The following general guidelines have been
   adopted in  establishing the uncertainty factors:
   a.  Valid experiment results from studies on prolonged ingestion by man, with no
      indication of carcinogenicity. Uncertainty Factor = 10
   b.  Experimental results of studies of human ingestion not available or scanty (e.g.,
      acute  exposure only)  with valid results  of  long-term  feeding studies on
      experimental animals, or in the absence of human studies, valid animal studies on
      one or more species. No indication of carcinogenicity. Uncertainty Factor = 100
   c.  No long-term or acute human data. Scanty results on experimental animals with
      no indication of carcinogenicity. Uncertainty Factor = 1,000
       Considerable judgment must be used in selecting the appropriate safety factors
   for deriving a criterion. In those cases where the data do not completely fulfill the
   conditions  for one category and appear to be intermediate between two categories,
   an intermediate uncertainty factor is used. Such as intermediate uncertainty factor
   may be developed based on a logarithmic scale (e.g., 33 being halfway between 10
   an d 100 on  a logarithmic scale).
       In determining the appropriate use of the uncertainty factors, the phrase "no
   indication of carcinogenicity" is interpreted as the absence of carcinogenicity data
   from animal experimental studies or human epidemiology. Available short-term
   carcinogenicity screening tests are reported in the criteria documents, but they are
   used neither for derivation of numerical criteria nor to rule out the uncertainty
   factor approach.
       Because of the high degree of judgment involved in the selection of a safety
   factor, the criterion derivation section of each document should provide a detailed
   discussion  and justification for both the selection of the safety factor and the data to
   which it is applied. This discussion should reflect a critical review of the available
   data base. Factors to be considered include number of animals, species, and
   parameters tested; quality of controls; dose levels; route; and dosing schedules. An
   effort should be made to differentiate between results that constitute a
   toxicologically sufficient data base and data which may be spurious in nature.

2.  Use of Acceptable Daily Intake (ADI).
       For carcinogens, the assumption of low-dose linearity precludes the necessity
   for defining total exposure in the estimation of increased incremental risk. For
   non-carcinogens, ADIs and criteria derived therefrom are calculated from total
   exposure data that include contributions from the diet and air. The equation used to
   derive the criterion (C) is:

       C = ADI - (DT+IN) / [21 + (0.0065 kg x R)]
       where
                21 = assumed daily water consumption
        0.00065 kg = assumed daily fish consumption
                R = bioconcentration factor in units of 1 / kg
               DT = estimated non-fish dietary intake
               IN = estimated daily intake by inhalation.
       If  estimates of  IN and DT cannot be  provided  from experimental data, an
   assumption must be made concerning total exposure. The inability to estimate DT
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           and IN due to either lack of data or the wide variability in DT and IN in different
           states may add an additional element of uncertainty to the criterion formulation
           process. To achieve scientific validity, the accurate estimate of the Acceptable Daily
           Intake is the major factor in satisfactory derivation of water quality criteria.

       3.  Use of Threshold Limit Values or Animal Inhalation Studies.
              Threshold Limit Values (TLVs) are established by the American Conference of
           Governmental and Industrial Hygienists (ACGIH) and represent 8-hour
           time-weighted average concentrations in air that are intended to protect workers
           from various adverse health effects over a normal working lifetime. Similar values
           are set by NIOSH (criteria) and OSHA (standards) for 10- and 8-hour exposures,
           respectively. To the extent that these values are based on sound toxicologic
           assessments and have been protective in the work environment, they provide
           useful information for deriving or evaluating water quality criteria. However, each
           TLV must be carefully examined to determine if the basis of the TLV contains data
           that can be used directly to derive a water quality criterion using the uncertainty
           factor approach. In addition, the history of each TLV must be examined to assess the
           extent to which it has assured worker safety. In each case, the types of effects against
           which TLVs are designed to protect are examined relative to exposure from water. It
           must be demonstrated that the chemical is not a localized irritant and that the effect
           at the site of entry is not significant irrespective of the routes of exposure (i.e., oral or
           inhalation).
               If the TLV or similar value is recommended as the basis of the criterion,
           consideration of the previous points is explicitly stated in the document's criterion
           derivation section. Particular emphasis is placed on the quality of the TLV relative
           to the available toxicity data that normally is given priority over TLVs or similar
           established values. If the TLV can be justified as the basis for the criterion, then the
           problems associated with estimating acceptable oral doses from inhalation data
           must be addressed.
               Estimating equivalencies of dose-response relationships from one route of
           exposure to another introduces an additional element of uncertainty in the criteria
           derivation. Consequently, whenever possible, ambient water quality criteria should
           be based on data involving oral exposures. If oral data are insufficient, data from
           other routes of exposure may be useful in the criterion derivation process.
               Inhalation data, including TLVs or similar values, are the most common
           alternatives to oral data. Estimates of equivalent doses can be based upon (1)
           available pharmacokinetic data for oral and inhalation routes, (2) measurements of
           absorption efficiency from ingested or inhaled chemicals, or (3) comparative
           excretion data when the associated metabolic pathways are equivalent to those
           following oral ingestionor inhalation. Given that sufficient pharmacokinetic data
           are available, the use of accepted pharmacokinetic models provides the most
           satisfactory approach for dose conversions. However, if available pharmacokinetic
           data are marginal or of questionable quality, pharmacokinetic modeling is
           inappropriate.
               The Stokinger and Woodward (1958) approach, or similar models based on
           assumptions  of breathing rate and absorption efficiency, represents possible
           alternatives when data are not sufficient to justify pharmacokinetic modeling. Such
           alternative approaches, however, provide less satisfactory approximations because
           they are not based on pharmacokinetic data. Consequently, in using the Stokinger
           and Woodward or related models, the basis and uncertainties inherent in each
           assumption must be clearly stated in the derivation of the criterion.
               The use of data pertaining to other routes of exposure to derive water quality
           criteria may also be considered. As with inhalation data, an attempt is made to use
           accepted toxicologic and pharmacokinetic principles to estimate equivalent oral
           doses. If simplifying assumptions are used, their bases and limitations must be
           clearly specified.
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          Because of the uncertainties involved in extrapolating from one route of
       exposure to another and the consequent limitations that this may place on the
       derived criterion, the decision to disallow such extrapolation and recommend no
       criterion is highly judgmental and must be made on a case-by-case basis. A decision
       for or against criteria derivation must balance the quantity and quality of the
       available data against a perceived risk to the human population.
          If the Stokinger and Woodward (1958) approach is used to calculate an ADI
       from a TLV, the general equation is
                   ADI= TLVxBRxDExd;tAA/ (A0xSF)
          where:
                  ADI =  Acceptable daily intake in mg
                  TLV =  Concentration in air in mg/m
                   DE =  Duration of exposure in hours per day
                     d =  5 days/7 days
                   AA =  Efficiency of absorption from air
                   A0 =  Efficiency of absorption from oral exposure
                   SF =  Safety factor following guidelines given above
                   BR =  Amount of air breathed per day; assume 10m3
          For deriving an ADI from animal toxicity data, the equation is
                   ADI= CAxDExdxAAxBRx70kg/(BWA;tA0xSF)
          where:
                  ADI =  Acceptable daily intake in mg
                   CA =  Concentration in air in mg/m3
                   DE =  Duration of exposure in hours per day
                     d =  Number of days exposed /number of days observed
                   AA =  Efficiency of absorption from air
                   BR =  Volume of air breathed per day in m3
                 70 kg =  Assumed human body weight
                 BWA =  Body weight of experimental animals in kg
                   A0 =  Efficiency of absorption from oral exposure
                   SF =  Safety factor following guidelines given above
          More  formal pharmacokinetic models must be developed  on a  compound-
       by-compound basis.
          Safety factors used in the above formulae are intended to account for species
       variability. Consequently, the mg surface area/day conversion factor is not used in
       the derivation of toxicity based criterion.
C. Organoleptic Criteria
       Organoleptic criteria define concentrations of materials that impart undesirable taste
   and/or  odor  to water. In developing and utilizing such criteria two factors  must be
   appreciated: the limitations of most Organoleptic data and the human health significance
   of Organoleptic properties.
       The publications that report taste and odor thresholds are, with few exceptions,
   cryptic  in their descriptions of test methodologies, number  of subjects tested,
   concentration/response   relationships,  and   sensory  characteristics   at   specific
   concentrations above threshold. Thus, the  quality of Organoleptic  data  is often
   significantly less than  that of toxicologic data used in establishing other  criteria.
   Consequently, a critical evaluation of the available Organoleptic data must be made and
   selection of the most appropriate data base for the criterion  based on sound scientific
   judgment.

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           Organoleptic criteria are not based on toxicologic information and have no direct
        relationship to potential adverse human health effects. Sufficiently intense organoleptic
        characteristics could result in depressed fluid intake that, in turn, might aggravate a
        variety of functional disease states (i.e., kidney and circulatory diseases). However, such
        effects are not used in the derivation process or organoleptic criteria unless available data
        would indicate an indirect human health effect via decreased fluid consumption; criteria
        derived solely from organoleptic data are based upon aesthetic qualities only.
           Since organoleptic and human health effects criteria are based on different endpoints,
        a distinction must be made between these two sets of information. In criteria summaries
        involving both types of data, the following format is used:
              For comparison purposes, two approaches were used  to derive criterion
           levels for 	. Based on available toxicity data, for the protection of
           public health the derived level is	. Using available organoleptic data, for
           controlling undesirable taste and odor quality of ambient water the estimated
           level is	. It should be recognized that organoleptic data as a basis for
           establishing  a water quality criteria  have no  demonstrated  relationship to
           potential adverse human health effects.
              In  those instances where a  level to limit toxicity cannot be derived, the
           following statement is to be appropriately inserted:
              Sufficiently data are not available for	to derive a level that would
           protect against the potential toxicity of this compound.

    D.  Criteria for Chemical Classes
           A chemical class is broadly defined as any group of  chemical compounds that are
        reviewed in a single risk assessment document. In criterion derivation, isomers should be
        regarded as a part of a chemical class rather than as a single compound. A class criterion is
        an estimate of risk/safety that applies to more than one member of a class. It uses
        available data on one or more chemicals of a class to derive criteria for other compounds
        of  the  same class in  the  event that  insufficient  data  are available  to derive
        compound-specific criteria.
           A class criterion usually applies to each member of a class rather than to the sum of the
        compounds within the class. While the potential hazards of multiple toxicant exposure
        are not to be minimized, a criterion, by definition, most often applies to an individual
        compound. Exceptions may be made for complex mixtures that are produced, released,
        and lexicologically tested as mixtures (e.g., toxaphene and PCBs). For such exceptions,
        some attempt is made to assess the  effects of environmental partitioning (i.e., different
        patterns of environmental transport and degradation) on the criterion's validity. If these
        effects cannot be assessed, an appropriate statement of uncertainty should accompany the
        criterion.
           Since relatively minor structural changes within a class of compounds can have
        pronounced effects on  their biological activities, reliance on class criteria should be
        minimized. Whenever sufficient toxicologic data are available on a chemical  within a
        class, a compound-specific criterion should be derived. Nonetheless, for some chemical
        classes, scientific judgment may suggest a sufficient degree of similarity among chemicals
        within a class to justify a class criterion applicable to some of all members of a class.
           The  development of a class criterion takes into consideration the following:
        1.  A detailed review of the chemical and physical properties of chemicals within the
           group should be made. A close relationship within the class with respect to chemical
           activity would suggest a similar potential to reach common biological sites within
           tissues.  Likewise,  similar  lipid  solubilities would suggest  the  possibility of
           comparable absorption and tissue distribution.

        2.  Qualitative and quantitative  data for chemicals within the group  are examined.
           Adequate toxicologic data on a number of compounds within a group provides a
           more reasonable basis for extrapolation  to other chemicals  of the same class than
           minimal data on one chemical or a few chemicals within the group.
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   3.  Similarities in the nature of the toxicologic response to chemicals in the class provides
       additional support for the prediction that the response to other members of the class
       may be similar. In contrast, where the biological response has been shown to differ
       markedly on a qualitative and quantitative basis for chemicals  within a class, the
       extrapolation of a criterion to other members of that class is not appropriate.

   4.  Additional support for the validity of extrapolation of a criterion to other members of
       a class could be provided by evidence of similar metabolic and pharmacokinetic data
       for some members of the class.
       Based on the above considerations, in some cases a chemical class may be divided into
   various subclasses.  Such  divisions  could be based  on  biological  endpoints (e.g.,
   carcinogens/non- carcinogens), potency, and/or sufficiency of data (e.g., a criterion  for
   some members of a class but no criterion for others). While no a priori limits can be placed
   on the extent of subclassification, each subclassification must be explicitly justified by the
   available data.
       Class criteria, if properly derived  and supported, can constitute valid scientific
   assessments of potential risk/ safety. Conversely, the development of a class criterion from
   an insufficient data base can lead to serious errors in underestimating or overestimating
   risk/safety and should be rigorously avoided. Although scientific judgment has a proper
   role in the development of  class criteria, such criteria are useful and defensible only if
   based on adequate data and scientific  reasoning. The definition of sufficient  data on
   similarities in physical, chemical, pharmacokinetic, or toxicologic properties to justify a
   class criterion may vary markedly, depending on the degree of structural similarity and
   the gravity of the perceived risk.
       Consequently, the criterion derivation section of each document in which a class
   criterion is recommended must explicitly address each of the key issues discussed above,
   and define, as clearly as possible, the limitations of the proposed criterion as well as the
   type of data needed to generate a compound-specific criterion.
       A class criterion should be abandoned when sufficient data is available to derive a
   compound-specific criterion that protects against the biological effect of primary concern;
   e.g., the availability of a good subchronic study would not necessarily result in the
   abandonment of a class criterion based on potential carcinogenicity.
       The inability to derive  a valid class criterion does not, and should not, preclude
   regulation of a compound or group of compounds based on concern for potential human
   health effects. The failure to recommend a criterion is simply a statement that the degree
   of concern cannot be quantified based  on the available data and risk assessment
   methodology.

E. Essential Elements
       Some chemicals, particularly certain metals, are essential to biological organisms at
   low levels but may be toxic  and/or carcinogenic at high levels. Because of potential toxic
   effects, criteria should be established for such essential elements. However, criteria must
   consider essentiality and cannot be established at levels that would result in deficiency of
   the element in the human population.                                     °
       Elements are accepted as essential if listed by NAS Food and Nutrition Board or a
   comparably qualified panel. Elements not yet determined to be essential but for which
   supportive data on essentiality exists need to be further reviewed by such a panel.
       To modify the toxicity and  carcinogenicity based criteria,  essentiality must  be
   quantified  either  as a "recommended daily allowance"  (RDA) or "minimum daily
   requirement" (MDR). These levels are then compared to estimated daily doses associated
   with the adverse effect of primary concern. The difference between the RDA or MDR and
   the daily doses causing a specified risk level for carcinogens or ADIs for non-carcinogens
   defines the spread of daily doses from which the criterion may be derived. Because errors
   are inherent  in defining both essential and maximum tolerable  levels, the criterion is
   derived from dose levels near the center of such a dose range. The decision to use either

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        the MDR or RDA is guided by the spread of the doses and the quality of the essentiality
        and toxicity estimates.
           The modification of criteria by consideration of essentiality must take into account all
        routes of exposure. If water is a significant source of the MDR or RDA, the criterion must
        allow for attainment of essential intake. Conversely, even when essentiality may be
        attained from nonwater sources, standard criteria derivation methods may be adjusted if
        the derived criterion represents a small fraction of the ADI or MDR. On a case-by-case
        basis, the modification in the use of the guidelines may include the use of different safety
        factors for non-carcinogens or other modifications which can be explicitly justified.

    F.  Use of Existing Standards
           For some chemicals for which criteria are to be established, drinking water standards
        already exist. These  standards represent not only a critical assessment of literature, but
        also  a  body  of human experience since their promulgation. Therefore, accepting the
        existing standard is valid unless compelling evidence exists to the contrary. This decision
        should be made after considering the existing standards versus new scientific evidence
        that has accumulated since the standards have been established. In several instances, the
        peer review process recommended usage of the present drinking water standards.
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                               APPENDIX D
            Derivation of 1976 Philosophy of
                       Aquatic Life Criteria
Water quality criteria specify concentrations of water constituents that, if not exceeded, are
expected to support an organic ecosystem suitable for the higher uses of water. Such criteria are
derived from scientific facts obtained from experimental or in situ observations that depict organic
responses  to a  defined stimulus or  material under identifiable or regulated environmental
conditions for a specified time period.
   Water quality criteria are not intended to offer the same degree of strategy for survival and
propagation at all times to  all organisms within a given ecosystem. They are intended not only to
protect essential and significant life in water and the direct users of water but also to protect life that
is dependent on water for its existence or may consume intentionally or unintentionally any edible
portion of such life.
   The criteria  levels for  domestic water supply incorporate available data  for human health
protection. Such values are different from the criteria levels necessary for protection of aquatic life.
The Agency's interim primary drinking water regulations (40 Federal Register 59566, December 24,
1975), as required by the Safe Drinking Water Act (42 U.S.C. 300f, et  seq.), incorporate applicable
domestic water  supply criteria. Where pollutants are identified in  both the quality criteria for
domestic water supply and the Drinking Water Standards, the concentration levels are identical.
Water treatment may not significantly affect the removal of certain pollutants.
   What is essential and significant life in water? Do Daphnia or stonefly nymphs qualify as such
life? Why does 1 / 100th of a concentration that is lethal to 50 percent of the test organisms (LC50)
constitute a criterion in some instances, whereas 1/2 or I/10th of some effect levels constitutes a
criterion in other instances? These are questions often asked of those who undertake the task of
criteria formulation.
   The universe of organisms composing life in water is great in both kinds and numbers. As in the
human population, physiological variability exists among individuals of the same species in
response to a given stimulus. A much greater response variation exists among species of aquatic
organisms. Thus, aquatic organisms do not exhibit the same degree of harm, individually or by
species, from a given concentration of a toxicant or potential toxicant within the environment.
   In establishing a level or concentration of a quality constituent as a criterion, it is necessary to
ensure a reasonable degree of safety for  those more sensitive species that are important to the
functioning of the aquatic  ecosystem, even though data on such species' response to the quality
constituent under consideration may  not be  available. The aquatic food web is an intricate
relationship of predator and prey organisms. A water constituent that may in some way destroy or
eliminate an important segment of that food web would,  in all  likelihood, destroy or seriously
impair other organisms associated with it.
    Although experimentation relating to the effects  of particular substances under controlled
conditions began in the early 1900s, the effects of any substance on  more than a few of the vast
number of aquatic organisms have not been investigated. Certain test animals have been selected
by investigators for intensive investigation because of their importance to man, their availability to
the researcher,  and their  physiological responses  to the  laboratory environment.  As  general
indicators of organism responses, such test organisms are representative of the expected results for
other associated organisms. In this context, Daphnia or stoneflies or other associated organisms
indicate the general levels of toxicity to be expected  among untested species. In addition, test

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organisms are themselves vital links within the food web that result in the fish population in a
particular waterway.
   The ideal data base for criteria development would consist of information on a large percentage
of aquatic species and would show the community response to a range of concentrations for a
tested constituent during a long time period. This data is not available, but investigators are
beginning to derive such information for a few water constituents. Where only 96-hour bioassay
data are available, judgmental prudence dictates that a substantial safety factor be employed to
protect all life stages of the test organism in waters of varying quality, as well as associated
organisms within the aquatic environment that have not been tested and that may be more sensitive
to the test constituent.
   Application factors have been used to provide the degree of protection required. Safe levels for
certain chlorinated hydrocarbons and heavy metals were estimated by applying an 0.01 application
factor to the 96-hour LC50 value for sensitive aquatic organisms. Flow-through bioassays have been
conducted for some test indicator organisms over a substantial period of their life history. In a few
other cases, information is available for the organism's natural life or for more than one generation
of the species. Such data may indicate a minimal effect level, as well as a no-effect level.
   The word "criterion" should not be used interchangeably with or as a synonym for the word
"standard." The word "criterion" represents a  constituent concentration or level associated with a
degree of environmental effect upon which scientific judgment may be based. As it is currently
associated with the water  environment, it has come to mean a designated concentration of a
constituent that, when not exceeded, will protect an organism, an organism community, or a
prescribed water use or quality with an adequate degree of safety. A criterion, in some cases, maybe
a narrative statement instead  of a constituent concentration. On the other hand, a standard
connotes a legal entity for a particular reach of waterway or for an effluent. A water quality
standard may use a water quality criterion as a basis for regulation or enforcement, but the standard
may differ from a  criterion because of prevailing local natural conditions — such  as naturally
occurring organic acids — or because of the importance of a particular waterway, economic
considerations, or the degree of safety to a particular ecosystem that may be desired.
   Toxicity  to aquatic life generally is expressed in terms of acute (short-term) or chronic
(long-term) effects. Acute toxicity refers to effects occurring in a short time period: often death is the
end point. Acute toxicity can be expressed as the lethal concentration for a stated percentage of
organisms tested, or the reciprocal, which is the tolerance limit of a percentage of surviving
organisms. Acute toxicity for aquatic organisms generally has been expressed for 24- to 96-hour
exposures.
    Chronic toxicity refers  to effects through  an extended time period. Chronic toxicity may be
expressed in terms of an observation period equal to the lifetime of an organism or to the time span
of more than one generation. Some chronic effects may be reversible, but most are not.
    Chronic effects often occur in the species population rather than in the individual. If eggs fail to
develop or the sperm does not remain viable, the species would be eliminated from an ecosystem
because of reproductive failure. Physiological stress may make a species less competitive with
others and may result in a gradual population decline or absence from an area.
    The elimination of a microcrustacean that serves as a vital food during the larval period of a
fish's life could result ultimately in the elimination of the fish from an area. The phenomenon of
bioaccumulation of certain materials may result in chronic toxicity to the ultimate consumer in a
food chain. Thus, fish may mobilize lethal toxicants from their fatty tissues  during periods of
physiological stress; egg shells of predatory birds may be weakened to a point of destruction in the
nest; and bird chick embryos may have increased mortality rates. There may be a hazard to the
health of man if aquatic organisms with toxic residues are consumed.
    The fact that living systems (i.e., individuals, populations, species, and ecosystems) can take up,
accumulate, and bioconcentrate human-made and natural toxicants is well documented. In aquatic
systems, biota are exposed directly to pollutant  toxicants through submersion  in a relatively
efficient solvent (water) and  are exposed  indirectly through food webs and other biological,
chemical, and physical interactions.  Initial toxicant levels, if not immediately toxic and damaging,
may accumulate in the biota or sediment over time  and increase to levels that are lethal  or

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sublethally damaging to aquatic organisms or to consumers of these organisms. Water quality
criteria reflect a knowledge of the capacity for environmental accumulation, persistence, and effects
of specific toxicants in specific aquatic systems.
    Ions  of toxic materials  frequently cause adverse effects because they pass  through the
semipermeable membranes of an organism. Molecular diffusion through membranes may occur
for  some compounds  such  as pesticides, polychlorinated biphenyls, and other toxicants. Some
materials may not pass through membranes in their natural or waste-discharged state, but in water
they may be converted to states that have increased ability to affect organisms. For example, certain
microorganisms  can methylate mercury, thus producing a material that more readily enters
physiological systems. Some materials may have multiple effects: for example, an iron salt may not
be toxic; an iron  floe or gel may be an irritant or clog fish gills to effect asphyxiation; iron at low
concentrations can be a trace nutrient but at high concentrations it can be a toxicant.
    Materials also can affect organisms if their metabolic byproducts cannot be excreted. Unless
otherwise stated, criteria are based on the total concentration of the substance because an ecosystem
can produce chemical, physical, and biological changes that may be detrimental to organisms living
in or using the water.
    In prescribing water quality criteria, certain fundamental principles dominate the reasoning
process. Establishing a level or concentration as a criterion for a given constituent assumed that
other factors within the aquatic environment are acceptable to maintain the integrity of the water.
Interrelationships and interactions  among organisms and  their environment, as well as the
interrelationships of sediments and the constituents they contain to the water above, are recognized
as fact.
    Antagonistic and  synergistic reactions among many quality constituents in  water also are
recognized as fact. The precise definition of such reactions and their relative effects on particular
segments of aquatic life have not been identified with scientific precision. Historically, much of the
data to support criteria development was of an ambient concentration-organism response nature.
Recently, data are becoming available on long-term chronic effects on particular species. Studies
now determine carcinogenic, teratogenic, and other insidious effects of toxic materials.
    Some unpolluted waters  in  the Nation may exceed designated criteria  for particular
constituents. The natural quality of water is variable and certain organisms become adapted to that
quality, which may be considered extreme in other areas. Likewise, a single criterion cannot identify
minimal quality for the protection of the integrity  of water for every aquatic  ecosystem in the
Nation. Providing an adequate degree of safety to protect against long-term effects may result in a
criterion that cannot be detected with present analytical tools. In some cases, a mass balance
calculation can assure that the integrity of the waterway is not being degraded.
    Water quality criteria  do not have direct regulatory impact,  but they form the  basis for
judgment in several U.S. Environmental Protection Agency programs that are derived from water
quality considerations. For example, water quality standards developed by the States under section
303 of the Act and approved by EPA are to be based on the water quality criteria, appropriately
modified to take account of local conditions. The local conditions to be considered include actual
and projected uses of the water, natural background levels of particular constituents, the presence
or  absence of sensitive important  species,  characteristics of the  local biological community
temperature  and  weather, flow characteristics,  and  synergistic or antagonistic effects  of
combinations of pollutants.
    Similarly, by providing a judgment on desirable  levels of ambient water quality, water quality
criteria are the starting point in deriving toxic pollutant effluent standards pursuant to section
307(a) of the Act. Other EPA programs that use water quality criteria involve drinking  water
standards, the ocean dumping program, designation of hazardous substances, dredge spoil criteria
development, removal of in-place toxic materials, thermal pollution, and pesticide registration.
    To provide the water resource protection for which they are  designed, quality criteria should
apply to virtually all of the Nation's navigable waters with modifications for local conditions as
needed. To violate quality criteria for any substantial length of time or in any substantial portion of
a waterway may result in an adverse affect on aquatic life and perhaps a hazard to humans or other
consumers of aquatic life.

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    Quality criteria have been designed to provide long-term protection. Thus, they may provide a
basis  for effluent standards, but criteria  values need not become effluent standards. Certain
substances can be applied to the aquatic environment with the concurrence of a governmental
agency for the precise purpose of controlling or managing a portion of the aquatic ecosystem;
aquatic herbicides and pesticides are examples of such substances. For such occurrences, criteria
obviously do not apply.
    In addition, pesticides applied according to official label instructions to agricultural lands and
forestlands may be washed to a receiving  waterway by a  torrential rainstorm.  Under such
conditions, such diffuse source inflows should receive consideration similar to that of a discrete
effluent discharge, and in such instances the criteria should be applied to the principal portion of
the waterway rather than to that peripheral portion receiving the diffuse inflow.
    The format for presenting water quality criteria includes a concise statement of the dominant
criterion or criteria for a particular constituent followed by a narrative introduction and a listing of
the references cited within the rationale. An effort has been made to restrict supporting data to those
that either have been published or are in press awaiting publication. A particular constituent may
have more than one criterion to ensure more than one water use or condition, i.e., hard or soft water
where applicable, suitability as a drinking water supply source, protection of human health when
edible portions of selected biota are consumed, provision for recreational bathing or waterskiing,
and permitting an appropriate factor of safety to ensure protection for essential warm- or coldwater
associated biota.
    Criteria are presented for those substances that may occur in water where data indicate the
potential for harm to aquatic life, or to water users, or to the consumers of the water or aquatic life.
Presented criteria do not represent an all-inclusive list of constituent contaminants. Omissions from
criteria should not be construed to mean that an omitted quality constituent is either unimportant
or nonhazardous.
Excerpted from 'Q uality Criteria for Water," 1976, available from National Technical Information Service, #PB-263-943.
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                     Appendix E

         Bioconcentration Factors
Used in the Calculation of Human Health Criteria
        CHEMICAL NAME	BCF (3% lipid; I/kg)
        Acenaphthene                          242
        Acrolein                              215
        Acrylonitrile                            30
        Aldrin                               4,670
        Anthracene                             30
        Antimony                               1
        Arsenic                                44
        Benzene                                5.2
        Benzidine                              87.5
        Benzofluoranthene, 3,4-                    30
        Benzo(A) Anthracene                      30
        Benzo(A) Pyrene                         30
        Benzo(K) Fluoranthene                    30
        Bromoform                              3.75
        Butylbenzyl Phthalate                    414
        Cadmium                              64
        Carbon Tetrachloride                      18.75
        Chlordane                           14,100
        Chlorobenzene                          10.3
        Chlorodibromomethane                    3.75
        Chloroform                              3.75
        Chloronaphthalene,2-                    202
        Chlorophenol, 2-                        134
        Chrysene                              30
        Copper                                36
        Cyanide                                1
        DDT                               53,600
        ODD                               53,600
        DDE                               53,600
        Dibenzo(A,H) Anthracene                  30
        Di-N-Butyl Phthalate                      89
        Dichlorobenzene, 1,2-                      55.6
        Dichlorobenzene, 1,3-                      55.6
        Dichlorobenzene, 1,4-                      55.6
        Dichlorobenzidine, 3,3-                   312
        Dichlorobromethane                       3.75
                                                               287

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                 CHEMICAL NAME
BCF (3% lipid; I/kg)
                 Dichloroethane, 1,1-
                 Dichloroethane, 1,2-
                 Dichloroethylene, 1,1-
                 Dichloroethylene, trans, 1,2-
                 Dichlorophenol, 2,4-
                 Dichloropropane, 1,2-
                 Dichloropropylene, 1,3-
                 Dieldrin
                 Diethyl Phthalate
                 Dimethylphenol, 2,4-
                 Dimethyl Phthalate
                 Dinitrophenol, 2,4-
                 2-Methyl-4,6-Dinitrophenol
                 Dinitrotoluene, 2,4-
                 Dioxin (2,3,7,8-TCDD)
                 Diphenylhydrazine, 1,2-
                 Di-2-Ethylhexyl Phthalate
                 Endosulfan-Alpha
                 Endosulfan-Beta
                 Endosulfan Sulfate
                 Endrin
                 Endrin Aldehyde
                 Bis(2-Chloroethyl) Ether
                 Bis(2-Chloroisopropyl) Ether
                 Bis(Chloromthyl) Ether
                 Ethylbenzene
                 Fluoranthene
                 Fluorene
                 Heptachlor
                 Heptachlor Epoxide
                 Hexachlorobenzene
                 Hexachlorobutadiene
                 Hexachlorocyclohexane-Alpha(A-BHC)
                 Hexachlorocyclohexane-Beta(B-BHC)
                 r"iexachlorocwclohexane-Garnm3 ^
                 Hexachlorocyclohexane-Deltap-BHC)
                 Hexachlorocyclopentadiene
                 Hexachloroethane
                 Indeno (1,2,3-CD) Pyrene
                 Isophorone
                 Mercury
                 Methyl Bromide
                 Methylene Chloride
                 Naphthalene
          1.2
          5.6
          1.58
         40.7
          4.11
          1.91
      4,670
         73
         93.8
         36
          1.5
          5.5
          3.8
      5,000
         24.9
        130
        270
        270
        270
      3,970
      3,970
          6.9
          2.47
          0.63
         37.5
      1,150
         30
     11,200
     11,200
      8,690
          2.78
        130
        130
        130
        130
          4.34
         86.9
         30
          4.38
      5,500 Freshwater
      3,760 Esturine
      9,000 Marine
          3.75
          0.9
         10.5
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         CHEMICAL NAME
BCF(3%lipid;l/kg)
         Nickel
         Nitronenzene
         N-Nitrosodimethylamine
         N-Nitrosodiphenylamine
         N-Nitrosodi-N-Propylamine
         PCB-1016
         PCB-1221
         PCB-1232
         PCB-1242
         PCB-1248
         PCB-1254
         PCB-1260
         Pentachlorophenol
         Phenanthrene
         Phenol
         Pyrene
         Selenium
         Silver
         Tetrachlorobenzene, 1,2,4,5-
         Tetrachlorethane, 1,1,2,2-
         Tetrachloroethylene
         Thallium
         Toluene
         Toxaphene
         Trichloroethane, 1,1,1-
         Trichloroethane, 1,1,2-
         Trichlorophenol, 2,4,6-
         Vinyl Chloride
         Zinc
         47
          2.89
          0.026
        136
          1.13
     31,200
     31,200
     31,200
     31,200
     31,200
     31,200
     31,200
         11
         30
          1.4
         30
          6
          0.5
      1,125
          5
         30.6
        116
         10.7
     13,100
          5.6
         10.6
        150
          1.17
         47
NOTE: The bioconcentration factors (BCFs) listed here were used in the calculation of the
human health criteria in this document. EPA is considering updating these BCFs or using
Bioaccumulation Factors (BAFs). Until EPA formally updates these BCFs, these numbers
should be used to calculate the human health criteria.
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                           APPENDIX F
         IVater Quality Criteria Documents
The U.S. Environmental Protection Agency has published water quality criteria for toxic
pollutant(s) categories. Copies of water quality criteria documents are available from the National
Technical Information Service (NTIS), 5285 Front Royal Road, Springfield, VA 22161, (703) 487-4650.
Prices of individual documents may be obtained by contacting NTIS.  Order numbers are listed
below. Where indicated, documents may be obtained from the Water Resource Center, 401 M St.,
S.W. RC-4100, Washington, DC 20460, (202) 260-7786.
               Chemical
NTIS Order No.   EPA Document No.
Acenaphthene
Acrolein
Acrylonitrile
Aesthetics
Aldrin/Dieldrin
Alkalinity
Aluminum
Ammonia
Ammonia (saltwater)
Antimony
Antimony (III) — aquatic
(draft)
Arsenic — 1980
— 1984
Asbestos
Bacteria — 1976
— 1984
Barium
Benzene
Benzidine
Beryllium
Boron
Cadmium — 1980
— 1984
Carbon Tetrachloride
Chlordane
Chloride
Chlorinated Benzenes
Chlorinated Ethanes
Chlorinated Naphthalene
Chlorinated Phenols
PB 81-117269
PB 81-117277
PB 81-117285
PB 263943
PB 81-117301
PB 263943
PB 88-245998
PB 85-227114
PB 89-195242
PB 81-117319
resource center
PB 81-117327
PB 85-227445
PB 81-117335
PB 263943
PB 86-158045
PB 263943
PB 81-117293
PB 81-117343
PB 81-117350
PB 263943
PB 81-117368
PB 85-224031
PB 81-117376
PB 81-117384
PB 88-175047
PB 81-117392
PB 81-117400
PB 81 -11 7426
PB 81-117434
EPA 440 75-80-015
EPA 440/5-80-016
EPA 440/5-80-017
.EPA 440/9-76-023
EPA440/5-80-019
EPA 440/9-76-023
EPA 440/5-86-008
EPA440/5-85-001
EPA 440/5-88-004
EPA 440/5-80-020

EPA440/5-80-021
EPA 440/5-84-033
EPA 440/5-80-022
EPA 440/9-76-023
EPA 440/5-84-002
EPA 440/9-76-023
EPA 440/5-80-018
EPA 440/5-80-023
EPA 440/5-80-024
EPA 440/9-76-023
EPA 440/5-80-025
EPA 440/5-84-032
EPA 440/5-80-026
EPA 440/5-80-027
EPA 440/5-88-001
EPA 440/5-80-028
EPA 440/5-80-029
EPA 440/5-80-031
EPA 440/5-80-032
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              Chemical
NTIS Order No.  EPA Document No.
Chlorine
Chloroalkyl Ethers
Chloroform
2-Chlorophenol
Chlorophenoxy Herbicides
Chlorpyrifos
Chromium — 1980
—1984
Color
Copper — 1980
— 1984
Cyanide
Cyanides
DDT and Metabolites
Demeton
Dichlorobenzenes
Dichlorobenzidine
Dichloroethylenes
2,4-Dichlorophenol
Dichloropropane /
Dichloropropene
2,4-Dimethylphenol
Dinitrotoluene
Diphenylhydrazine
Di-2-Ethylhexyl Phthalate -
aquatic (draft)
Dissolved Oxygen
Endosulfan
Endrin
Ethylbenzene
Fluoranthene
Gasses, Total Dissolved
Guidelines for Deriving
Numerical National
Water Quality Criteria
for the Protection of
Aquatic Organisms and
Their Uses
Guthion
Haloethers
Halomethanes
Hardness
Heptachlor
Hexachlorobenzene —
aquatic (draft)
Hexachlorobutadiene
Hexachlorocyclohexane
PB 85-227429
PB 81-11 7418
PB 81-117442
FB 81-117459
PB 263943
PB 87-105359
PB 81-117467
PB 85-227478
PB 263943
PB 81-117475
PB 85-227023
PB 85-227460
PB 81-117483
PB 81-117491
PB 263943
PB 81-117509
PB 81 -11 751 7
PB 81-117525
PB 81-117533
PB 81 -11 7541
PB 81 -11 7558
PB 81 -11 7566
PB 81 -11 7731
resource center
PB 86-208253
PB 81-117574
PB 81-117582
PB 81 -11 7590
PB 81-117608
PB 263943
PB 85-227049
PB 263943
PB 81-117616
PB 81-117624
PB 263943
PB 81-117632
resource center
PB 81 -11 7640
PB 81 -11 7657
EPA 440/5-84-030
EPA 440/5-80-030
EPA 440/5-80-033
EPA 440/5-80-034
EPA 440/9-76-023
EPA 440/5-86-005
EPA 440/5-80-035
EPA 440/5-84-029
EPA 440/9-76-023
EPA 440/5-80-036
EPA 440/5-84-031
EPA 440/5-84-028
EPA 440/5-80-037
EPA 440/5-80-038
EPA 440/9-76-023
EPA 440/5-80-039
EPA 440/5-80-040
EPA 440/5-80-041
EPA 440/5-80-042
EPA 440/5-80-043
EPA 440/5-80-044
EPA 440/5-80-045
EPA 440/5-80-062
EPA 440/5-86-003
EPA 440/5-80-046 .
EPA 440/5-80-047
EPA 440/5-80-048
EPA 440/5-80-049
EPA 440/9-76-023

EPA 440/9-76-023
EPA 440/5-80-050
EPA 440/5-80-051
EPA 440/9-76-023
EPA 440/5-80-052
EPA 440/5-80-053
EPA 440/5-80-054
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Chemical
NTIS Order No.   EPA Document No.
Hexachlorocyclopentadiene
Iron
Isophorone
Lead — 1980
— 1984
Malathion
Manganese
Mercury — 1980
— 1984
Methoxychlor
Mirex
Naphthalene
Nickel — 1980
— 1986
Nitrates /Nitrites
Nitrobenzene
Nitrophenols
Nitrosamines
Oil and Grease
Parathion
Pentachlorophenol — 1980
— 1986
PH
Phenanthrene — aquatic
(draft)
Phenol
Phosphorus
Phthalate Esters
Polychlorinated Biphenyls
Polynuclear Aromatic
Hydrocarbons
Selenium — 1980
— 1987
Silver
Silver — aquatic (draft)
Solids (dissolved) and
Salinity
Solids (suspended) and
Turbidity
Sulfides/ Hydrogen Sulfide
Tainting Substances
Temperature
2,3,7,8-Tetrachlorodibenzo-
P-Dioxin
Tetrachloroethylene
Thallium
Toluene
PB 81-11 7665
PB 263943
PB 81-117673
PB 81-117681
PB 85-227437
PB 263943
PB 263943
PB 81-117699
PB 85-227452
PB 263943
PB 263943
PB 81-117707
PB 81-117715
PB 87-105359
PB 263943
PB 81-117723
PB 81-117749
PB 81-117756
PB 263943
PB 87-105383
PB 81-117764
PB 87-105391
PB 263943
resource center
PB 81-117772
PB 263943
PB 81-117780
PB 81-117798
PB 81 -11 7806
PB 81-117814
PB 88-142239
PB 81-117822
resource center
PB 263943
PB 263943
PB 263943
PB 263943
PB 263943
PB 89-169825
PB 81-117830
PB 81-117848
PB 81-117863
EPA 440 75-80-055
EPA 4407 9-76-023
EPA 440 7 5-80-056
EPA 440 / 5-80-057
EPA 440 / 5-84-027
EPA 440 / 9-76-023
EPA 440 / 9-76-023
EPA 440 / 5-80-058
EPA 440 / 5-84-026
EPA 440 / 9-76-023
EPA 440 / 9-76-023
EPA 440 / 5-80-059
EPA 440 / 5-80-060
EPA 4407 5-86-004
EPA 440 / 9-76-023
EPA 440 / 5-80-061
EPA 440 / 5-80-063
EPA 440 / 5-80-064
EPA 440/9-76-023
EPA 440 / 5-86-007
EPA 440 / 5-80-065
EPA 440 / 5-85-009
EPA 440 / 9-76-023
EPA 440/5-80-066
EPA 440 / 9-76-023
EPA 440/5-80-067
EPA 440/5-80-068
EPA 440/5-80-069
EPA 440/5-80-070
EPA 440/5-87-008
EPA 440/5-80-071
EPA 440/9-76-023
EPA 440/9-76-023
EPA 440/9-76-023
EPA440/9-76-023
EPA 440/9-76-023
EPA 440/5-84-007
EPA 440/5-80-073
EPA 440/5-80-074
EPA 440/5-80-075
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                 Chemical                 NTIS Order No.   EPA Document No.

                 Toxaphene —1980         PB 81-117863      EPA 440/5-80-076
                           — 1986         PB 87-105375      EPA 440 75-86-006
                 Tributyltin — aquatic
                   (draft)                  resource center
                 Trichloroethylene          PB 81-117871      EPA 440 75-80-077
                 2,4,5-Trichlorophenol —
                   aquatic (draft)           resource center
                 Vinyl Chloride             PB 81-117889      EPA 440 75-80-078
                 Zinc —1980               PB 81-117897      EPA 440 7 5-80-079
                     — 1987               PB 87-143581      EPA 440 75-87-003
294

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