United States
Environmental Protection
Agency
Office of Science and Technology September 1993
Office of Water
Washington, D.C. 20460
SEPA 1993
Water Quality
Criteria
-------
Quality Criteria
for Water
1993
Prepared for
Health and Ecological Criteria Division
Office of Water
U.S. Environmental Protection Agency
Washington, D.C.
1993
-------
NOTE TO USERS
Quality Criteria for Water 1993 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 E. 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.
-------
PREFACE
Section 304(a)(1) 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)(1)
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 priority pol-
lutants criteria, based on data that was available at its release. Quality
Criteria for Water 1993 draws information from its predecessors in pre-
senting summaries of all the contaminants for which EPA has developed
criteria recommendations. The rationale for these recommendations can
be found in the reference identified at the end of each criteria summary.
-------
This document is intended as a summary only. Specific data on each cri-
terion can be found in individual criteria documents. Copies of the
individual ambient water quality criteria documents containing 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:
HUMAN HEALTH
Dr. Frank Gostomski
Chief, Surface Water Health Assessment Section
U.S. Environmental Protection Agency
401 M Street, SW (WH-586)
Washington, DC 20460
AQUATIC LIFE
Margarete Heber
Chief, Criteria Section
U.S. Environmental Protection Agency
401 M Street, SW (WH-586)
Washington, DC 20460
-------
WATER QUALITY CRITERIA SUMMARY
CONCENTRATIONS (in ng/L)
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Science and Technology
Health and Ecological Criteria Division
Ecological Risk Assessment Branch (WH-586)
Human Risk Assessment Branch (WH-586)
CAS#
Sd
tr O
o. a
HUMAN HEALTH (10-6 RISK LEVEL FOR CARCINOGENS)
PUBLISHED CRITERA
FRESH FRESH SALTWATER SALTWATER
ACUTE CHRONIC ACUTE CHRONIC WATER 8 ORGANISMS
CRITERIA CRITERIA CRITERIA CRITERIA ORGANISMS ONLY
RECALCULATED VALUES
using IRIS, as of 9/90
WATER &
ORGANISMS
ORGANISMS
ONLY
DRINKING
WATER MCL
CRITERIA
FEDERAL
REGISTER
NOTICE
ACENAPHTHENE 83-32-9 Y N "1,700. *520. *970. *710 1,200. 2,700 57 FR 60890
ACENAPHTHYLENE
208-96-8
Y
Y
57 FR 60913
ACROLEIN
107-02-8
Y
N
*68. *21. *55. 320.
780
45 FR 79324
ACRYLONI'I'RILE
107-13-1
Y
Y
*7,550. *2,600. 0.058
0 65
0.059
0.66
45 FR 79324
ALACHLOR
15972-60-8
N
Y
20
—
ALDRIN
309-00-2
Y
Y
3.0 1.3 0 000074
0 000079
0 00013
0.00014
45 FR 79325
ALKALINITY
N
N
20,000
RB
ALUMINUM
7429-90-5
N
N
CRITERIA ARE pH DEPENDENT — SEE DOCUMENT
53 FR 33178
AMMONIA
7664-41-7
N
N
CRITERIA ARE pH AND TEMPERATURE DEPENDEN 1 — SEE DOCUMEN T
54 FR 19227
AN1HRACENE
120-12-7
Y
Y
0.00012
0.00054
57 FR 60913
ANTIMONY
7440-36-0
Y
N
/p/88 /p/30 /p/1500 /p/500 146
45,000
14.
4,300.
45 FR 79325
ARSENIC
7440-38-2
Y
Y
0.0022
0.0175
0.018
0.14
45 FR 79325
ARSENIC(V)
17428-41-0
Y
Y
*850. *2,319.
50 FR 30789
ARSENIC(III)
22569-72-8
Y
Y
360. 190. 69. 36.
50 FR 30786
ASBESTOS
1332-21-4
Y
Y
30k fibers/L
7 MFL
57 FR 60911
ATRAZINE
1912-24-9
N
N
3 0
—
BACTERIA
N
N
FOR PRIMARY RECREATION AND SHELLFISH USES — SEE DOCUMENT
51 FR 8012
BARIUM
7440-39-3
N
N
1,000
/ p/2.000
RB
BENZENE
71-43-2
Y
Y
*5,300. *5,100 *700. 0.66
40.
1 2
71.
5.0
57 FR 60911
BENZIDINE
92-87-5
Y
Y
*2,500. 0.00012
0 00053
0 00012
0 00054
57 FR 60913
BENZOFLUORAN THENE, 3,4-
205-99-2
Y
Y
0.0028
0.0311
57 FR 60913
BENZO(A)
ANTHRACENE
56-55-3
Y
Y
0.0028
0.0311
57 FR 60913
50-32-8 Y Y 0.0028 0.0311 57 FR 60913
-------
CAS#
0C 3
2d
cc O
a a.
HUMAN HEALTH (10-6 RISK LEVEL FOR CARCINOGENS)
PUBLISHED CRITERA
FRESH FRESH SALTWATER SALTWATER
ACUTE CHRONIC ACUTE CHRONIC WATER & ORGANISMS
CRITERIA CRITERIA CRITERIA CRITERIA ORGANISMS ONLY
RECALCULATED VALUES
using IRIS, as of 9/90
WATER &
ORGANISMS
ORGANISMS
ONLY
CRITERIA
FEDERAL
DRINKING REGISTER
WATER MCL NOTICE
BENZO(K)
FLUORANTHENE 207-08-9 Y Y 0.0028 0.0311 57 FR 60913
BERYLLIUM
7440-41-7
Y
Y
*130.
*5.3
0.0037
0.0641
57 FR 60848
BETA PARI ICLE and
PHOTON ACTIVITY
—
N
Y
4 mrem
—
BHC
680-73-1
N
Y
*100.
*0 34
45 FR 79335
BROMOFORM
75-25-2
Y
Y
4.3
360.
57 FR 60911
BUTYLBENZYL
PHTHALATE
85-68-7
Y
N
3,000.
5,200.
57 FR 60890
CADMIUM
7440-43-9
Y
N
3.9+
1.1 +
43.
9.3
10.
50
57 FR 60848
CARBOFURAN
1563-66-2
N
N
40.
—
CARBON TE'l'RACHLORIDE
56-23-5
Y
Y
*35,200.
*50,000.
0 4
6.94
0.25
4.4
5.0
57 FR 60911
CHLORDANE
57-74-9
Y
Y
2.4
0.0043
0.09
0.004
0 00046
0.00048
0.00057
0.00059
2.0
45 FR 79327
CHLORIDE
16887-00-6
N
N
860,000.
230,000.
53 FR 19028
CHLORINATED
BENZENES
—
Y
Y
*250.
*50
*160.
*129.
488.
45 FR 79327
CHLORINATED
NAPHTHALENES
—
Y
N
*1,600.
*7.5
1,700.
4,300.
57 FR 60890
CHLORINE
7782 50-5
N
N
19.
11.
13
7.5
50 FR 30788
CHLOROALKYL
ETHERS
Y
N
*238,000.
45 FR 79330
CHLOROBENZENE
108-90-7
Y
N
488
680.
21,000.
100.
57 FR 60911
CHI.ORODIBRO-
MOMETHANE
124-48-1
Y
Y
0.41
34.
57 FR 60911
CHLOROFORM
67-66-3
Y
Y
*28,900.
*1,240.
0.19
15.7
5.7
470.
57 FR 60911
CHLOROPHENOL, 2-
95-57-8
Y
N
*4,380.
120.
400.
57 FR 60890
CHLOROPIIENOL, 4
106-48-9
N
N
*29,700.
45 FR 79329
CHLOROPHENOL, 4 ,
METHYL, 3-
59-50-7
Y
N
*30.
45 FR 79329
CHLOROPHENOXY
HERBICIDE (2,4,5,-TP)
93-72-1
N
N
10
50
RB
CHLOROPHENOXY
HERBICIDE (2,4-D)
94-75-7
N
N
100.
70.
RB
CHLORPYRIFOS
2921-88-2
N
N
0.083
0.041
0.011
0.0056
51 FR 43666
CHROMIUM (VI)
7440-47-3
Y
N
16.
11.
1,100
50.
50.
170.
3,400.
100.
50 FR 30788
-------
CAS#
fcfS
s 3
Q d
DC O
q. a.
FRESH
ACUTE
CRITERIA
FRESH
CHRONIC
CRITERIA
SALTWATER
ACUTE
CRITERIA
SALTWATER
CHRONIC
CRITERIA
HUMAN HEALTH (10-6 RISK LEVEL FOR CARCINOGENS)
PUBLISHED CRITERA
WATER &
ORGANISMS
RECALCULATED VALUES
using IRIS, as of 9/90
ORGANISMS
ONLY
WATER &
ORGANISMS
ORGANISMS
ONLY
DRINKING
WATER MCL
CRITERIA
FEDERAL
REGISTER
NOTICE
CHROMIUM (III) 1308-14-1 Y N 1,700.- 210.+ *10,300 170,000 3,433,000 33,000. 670,000. 100. 50 FR 30788
CHRYSENE
218-01-9
Y
Y
0 0028
0.0311
57 FR 60913
COLOR
—
N
N
NARRATIVE STATEMENT — SEE DOCUMENT
RB
COPPER
7440-50-8
Y
N
18 +
12.+ 2.9
/ p/1300.
50 FR 30789
CYANIDE
57-12-5
Y
N
22.
5.2 1.0
200
700.
220,000.
57 FR 60911
DDT
50-29-3
Y
Y
1.1
0 001 0.13 0 001
0.000024
0 000024
0.00059
0.00059
57 FR 60914
DDT METABOLITE
(DDD) ( IDE)
72-54-8
Y
Y
*0.6
*3.6
0 00083
0.00084
57 FR 60914
DDT ME TABOLITE
(DDE)
72-55-9
Y
Y
*1,050.
*14.
0 00059
0.00059
57 FR 60914
DEM ETON
8065-48-3
N
N
0.1 0.1
RB
DIBENZO(A,H)
ANTHRACENE
53-70-3
Y
Y
0.0028
0.0311
57 FR 60913
DIBROMOCHLORO-
PROPANE
96-12-8
N
Y
0.2
—
DI-N-BUTYL PHTHALATE
84-74-2
Y
N
34,000.
154,000.
2,700.
12,000.
57 FR 60913
DICHLOROBENZENE, 1,2-
95-50-1
Y
N
2,700.
17,000.
600.
57 FR 60913
DICHLOROBENZENE, 1,3-
541-73-1
Y
N
400.
2,600.
600.
57 FR 60913
DICHLOROBENZENE, 1,4-
106-46-7
Y
N
400.
2,600.
75.
57 FR 60913
DICHLOROBENZENES
25321-22-6
N
N
*1,120.
*763. *1,970.
400
2,600.
45 FR 79328
DICHLOROBENZIDINE, 3,3-
91-94-1
Y
Y
0 0103
0 0204
0.04
0.077
57 FR 60913
DICHLOROBROMO-
METHANE
75-27-4
Y
Y
0.27
2.2
57 FR 60911
DIC11LOROEITIANE, 1,2-
107-06-2
Y
Y
*118,000.
*20,000. *113,000
0 94
243
0.38
99.
5.0
57 FR 60912
DICHLOROE H IYLENE5
25323-30-3
N
Y
*11,600
*224,000.
45 FR 79332
DICHLOROEITIYLENE, 1,1-
75-35-4
Y
Y
0 033
1 85
0 057
3.2
7.0
57 FR 60912
DICHLOROE H IYLENE,
cis-1,2-
—
N
N
70
—
DICHLOROEITIYLENE,
trans, 1,2-
156-60-5
Y
N
700
100.
57 FR 60890
DICHLOROP! IENOL, 2,4-
120-83-2
Y
N
*2,020.
*365.
3090
93
790.
57 FR 60912
DICHLOROPROPANE
26638-19-7
N
N
*23,000.
*5,700. *10,300. *3,040.
5.0
45 FR 79333
DICHLOROPROPANE, 1,2-
78-87-5
Y
Y
0 52
39.
5 0
57 FR 60890
DICHLOROPROPENE
26952-23-8
N
N
*6,060
*244. *790
87.
14,1(X)
45 FR 79333
DICHLOROI'ROPYLENE, 1,3-
542-75-6
Y
N
10.
1,700.
57 FR 60912
-------
CAS#
Qd
tc. o
a. a.
FRESH
ACUTE
CRITERIA
FRESH
CHRONIC
CRITERIA
SALTWATER
ACUTE
CRITERIA
SALTWATER
CHRONIC
CRITERIA
HUMAN HEALTH (10-6 RISK LEVEL FOR CARCINOGENS)
PUBLISHED CRITERA
RECALCULATED VALUES
using IRIS, as of 9/90
WATER &
ORGANISMS
ORGANISMS
ONLY
WATER &
ORGANISMS
ORGANISMS
ONLY
DRINKING
WATER MCL
CRITERIA
FEDERAL
REGISTER
NOTICE
DIELDRIN
60-57-1
Y
Y
2.5
0.0019 0.71 0.0019
0.000071
0 00076
0.00014
0.00014
57 FR 60914
DIETHYL PHTHALATE
84-66-2
Y
N
350,000.
1,800,000.
23,000.
120,000.
57 FR 60913
DIMETHYL PHENOL, 2,4-
105-67-9
Y
N
*2,120.
540.
2,300.
57 FR 60890
DIMETHYL PHTHALATE
131-11-3
Y
N
313,000
2,900,000.
45 FR 79339
DINITROPHENOL, 2,4-
51-28-5
Y
N
70.
14,000.
57 FR 60912
DINITROPH ENOL
25550-58-7
Y
N
70.
14,300.
45 FR 79337
DINITROTOLUENE, 2,4-
121-14-2
Y
Y
*330.
*230. *590. *370.
0.11
9.1
45 FR 79333
DINITRO-O-CRESOL, 2,4-"
534-52-1
Y
N
134
765.
45 FR 79333
DIOXIN (2,3,7,8 - I'CDD)
1746-01-6
Y
Y
* <0.01
* <0.00001
0.000000013
0.000000014
49 FR 5831
DIPHENYLHYDRAZINE, 1,2-
122-66-7
Y
Y
*270.
0.042
0.56
0.041
0.54
57 FR 60913
DI-2-ETHYLHEXYL
PHTHALATE
117-81-7
Y
Y
*2,100.
*160.
15,000.
50,000.
1.8
5.9
45 FR 79339
ENDOSULFAN
115-29-7
N
N
0.22
0.056 0.034 0 0087
74
159.
45 FR 79334
ENDOSULFAN SULFATE
1031-07-8
Y
N
0.93
2.0
57 FR 60915
ENDOSULFAN-ALPHA
959-98-8
Y
N
0.22
0.056 0 034 0 0087
0.93
2.0
57 FR 60914
ENDOSULFA N-BETA
33213-65-9
Y
N
0.22
0.056 0.034 0.0087
0.93
2.0
57 FR 60914
ENDRIN
72-20-8
Y
N
0.18
0.0023 0.037 0.0023
1 0
0.76
0.81
57 FR 60915
ENDRIN ALDEHYDE
7421-93-4
Y
N
0.76
0.81
57 FR 60915
ETHER, BIS
(2-CH LOROETHYL)
111-44-4
Y
Y
0.03
1.36
0.031
1.4
57 FR 60913
ETHER, BIS
(2-CHLOROISOPROPYL)
108-60-1
Y
N
34 7
4360.
1,400.
170,000.
57 FR 60913
ETHER, BIS
(CHLOROMETHYL)
542-88-1
N
Y
0.00(X)038
0 00184
45 FR 79330
ETHYLBENZENE
100-41-4
Y
N
*32,000.
*430
1,400.
3280
3,100.
29,000.
700.
57 FR 60912
ETHYLENE DIBROMIDE
106-93-4
N
Y
0 05
—
FLUORAN'I HENE
206-44-0
Y
N
*3,980
*40. *I6.
42.
54
300.
370.
57 FR 60848
FLUORENE
86-73-7
Y
Y
0.0028
0.031
—
GASES, TO TAL DISSOLVED
—
N
N
NARRATIVE STATEMENT— SEE DOCUMENT
RB
GROSS ALPHA
PARTICLE ACTIVITY
N
Y
15 pCi/L
GUTHION
86-50-0
N
N
0.01 0.01
RB
HALOETHERS
N
N
*360.
*122.
45 FR 79334
HALOME'H IANES
—
N
Y
*11,000.
*12,000. *6,400
0.19
15 7
45 FR 79334
HEPTACHLOR
76-44-8
Y
Y
0.52
0 0038 0 053 0.0036
0 00028
0 00029
0.00021
0.00021
0.4
45 FR 79335
-------
HUMAN HEALTH (10-6 RISK LEVEL FOR CARCINOGENS)
l-
Ul
PUBLISHED CRITERA
RECALCULATED VALUES
f"
O
using IRIS, as of 9/90
CRfTERIA
2r 3
z
FRESH
FRESH
SALTWATER
SALTWATER
FEDERAL
o-i
o
tr
ACUTE
CHRONIC
ACUTE
CHRONIC
WATER &
ORGANISMS
WATER &
ORGANISMS
DRINKING
REGISTER
CAS#
12
<
o
CRITERIA
CRITERIA
CRITERIA
CRITERIA
ORGANISMS
ONLY
ORGANISMS
ONLY
WATER MCL
NOTICE
HEPTACHLOR EPOXIDE
1024-57-3
Y
Y
0.52
0.0038
0.053
0.0036
0.00010
0.00011
0.2
45 FR 79335
HEXACHLOROBENZENE
118-74-1
Y
Y
/p/6.0
/ p/3.68
0.00072
0.00074
0.00075
0.00077
57 FR 60912
HEXACHLOROBUTADIENE
87-68-3
Y
Y
*90.
*9.3
*32.
0 45
50.
0.44
50.
45 FR 79335
HEXACHLOROCYCLO-
HEXANE (LINDANE)
58-89-9
Y
Y
2.0
0.08
0.16
0.0186
0.0625
0.019
0.063
02
45 FR 79335
HEXACHLOROCYCLO-
HEXANE—ALPHA
319-84-6
Y
Y
0.0092
0.031
0.0039
0.013
57 FR 60914
HEXACHLOROCYCLO-
HEXANE—BETA
319-85-7
Y
Y
0.0163
0.0547
0.014
0.046
57 FR 60914
HEXACHLOROCYCLO-
HEXANE GAMMA
58-89-9
Y
Y
2.0
0.08
0.16
0.0186
0.0625
0.019
0.063
0.2
57 FR 60914
HEXACHLOROCYCLO-
HEXANE —TECHNICAL
319-86-8
N
Y
0.0123
0.0414
45 FR 79335
HEXACHLOROCYCLO-
PEN TADIENE
77-47-4
Y
N
*7.0
*5.2
*7.0
206.
240.
17,000.
57 FR 60914
HEXACHLOROETHANE
67-72-1
Y
Y
*980.
*540.
*940.
1.9
8.74
1.9
8.9
57 FR 60914
INDENO(l,2,3-CD)PYRENE
193-39-5
Y
Y
0.0028
0.0311
57 FR 60914
IRON
7439-89-6
N
N
1,000.
300.
RB
ISOPHORONE
78-59-1
Y
N
*117,000.
*12,900.
5,200
520,000
8.4
600.
57 FR 60914
LEAD
7439-92-1
Y
N
82.+
3.2+
220.
8.5
50.
/p/5.0
57 FR 60914
MA LATH ION
121-75-5
N
N
0.1
0 1
RB
MANGANESE
7439-96-5
N
N
50.
100
RB
MERCURY
7439-97-6
Y
N
2.4
0.012
2.1
0.025
0.144
0.146
0.14
0.15
2.0
50 FR 30791
METHOXYCHLOR
72-43-5
N
N
0.03
0.03
100
40.
RB
METHYL BROMIDE
74-83-9
Y
N
48.
4,000.
57 FR 60912
ME lT-IYL CHLORIDE
74-87-3
Y
Y
57 FR 60848
METHYLENE CHLORIDE
75-09-2
Y
Y
4.7
1,600.
57 FR 60912
MIREX
2385-85-5
N
N
0.001
0.001
RB
NAPHTHALENE
91-20-3
Y
N
*2,300.
*620.
*2,350.
45 FR 79337
NICKEL
7440-02-0
Y
N
1,400.+
160.+
75.
8.3
13.4
100
610.
4,600.
57 FR 60911
NITRATES
14797-55-8
N
N
10,000
10,OIK).
RB
NITRITE
—
N
N
1,000.
—
NITROBENZENE
98-95-3
Y
N
*27,000.
*6,680
19,800.
17.
1,900.
57 FR 60914
Nl'I-ROPHENOLS
Y
N
*230.
*150.
*4,850
45 FR 79337
NITROSAMINES
35576-91-1
Y
Y
*5,850
*3,300,000
45 FR 79337
-------
CAS#
(E
O
IE O
cl a.
HUMAN HEALTH (10-6 RISK LEVEL FOR CARCINOGENS)
PUBLISHED CRITERA
FRESH FRESH SALTWATER SALTWATER
ACUTE CHRONIC ACUTE CHRONIC WATER & ORGANISMS
CRITERIA CRITERIA CRITERIA CRITERIA ORGANISMS ONLY
RECALCULATED VALUES
using IRIS, as of 9/90
WATER &
ORGANISMS
ORGANISMS
ONLY
CRITERIA
FEDERAL
DRINKING REGISTER
WATER MCL NOTICE
NITROSODIBU'IYLAMINE, N-
924-16-3
N
Y
0.0064
0.587
45 FR 79338
NITROSODIETHYLAMINE, N-
55-18-5
N
Y
0.0008nK/L
0.0012
45 FR 79338
NITROSODIMETHYLAMINE,
N-
62-75-9
Y
Y
0.0014
16.
0.00069
8.1
57 FR 60914
NITROSODIPHENYLAMINE,
N-
86-30-6
Y
Y
4.9
16.1
50
16.
57 FR 60914
NITROSOPYROLIDINE, N-
930-55-2
N
Y
0.016
91.9
45 FR 79338
N-NITROSODI-N-
PROPYLAMINE
621-64-7
Y
Y
0.005
1.4
57 FR 60890
OIL AND GREASE
—
N
N
NARRATIVE STATEMENT — SEE DOCUMENT
RB
OXYGEN DISSOLVED
7782-44-7
N
N
WARMWATER AND COLDWATER CRITERIA MATRIX — SEE DOCUMENT
51 FR 22978
PARATHION
56-38-2
N
N
0.065
0.013
51 FR 43667
PCBs
1336-36-3
Y
Y
2.0
0.014
10.
0 03
0.000079
0 00(X)79
0 5
45 FR 79339
PCB-1016
12674-11-2
Y
Y
0.000044
0.000045
57 FR 60915
PCB-1221
11104-28-2
Y
Y
0.000044
0.000045
57 FR 60915
PCB-1232
11141-16-5
Y
Y
0.000044
0.000045
57 FR 60915
PCB-1242
5346-92-19
Y
Y
0.000044
0.000045
57 FR 60915
PCB-1248
12672-29-6
Y
Y
0.000044
0.000045
57 FR 60915
PCB-1254
11097-69-1
Y
Y
0.000044
0.000045
57 FR 60915
PCB-1260
11096-82-5
Y
Y
0 000044
0.000045
57 FR 60915
PENTACHLOROE1HANE
76-01-7
N
N
*7,240.
*1,100.
*390.
*281.
45 FR 79328
PENTACHLOROBENZENE
608-93-5
N
N
74.
85.
45 FR 79327
PENTACIILOROPHENOL
87-86-5
Y
N
*"20.
***13.
13.
7.9
1010
0.28
8.2
/p/1.0
57 FR 60912
pH
—
N
N
6.5-9
6.5-8.5
5-9
RB
PHENANITIRENE
85-01-8
Y
Y
/ p/30
/ p/6.3
/ p/7.7
/ p/4.6
57 FR 60848
PHENOL
108-95-2
Y-
N
*10,200.
*2,560.
*5,800.
3,500.
21,000.
4,600,000.
57 FR 60912
PHOSPHORUS ELEMENTAL
7723-14-0
N
N
0.1
RB
PHTHALATE ESTERS
—
Y
N
POLYNUCLEAR AROMATIC
HYDROCARBONS
Y
Y
*300.
0 0028
.0311
45 FR 79339
PYRENE
129-00-0
Y
Y
0.0028
0.0311
—
RADIUM 226/228
—
N
Y
5 pCi/L
—
SELENIUM
7782-49-2
Y
N
20.
5.0
300.
71.
10
50.
57 FR 60911
SILVER
7440-22-4
Y
N
4 1 + / p/0.92
0.12
2.3/p/7 2
/p/0.92
50
57 FR 60911
-------
CAS#
a. 3
Qd
DC o
0. £L
111
a
o
z
o
IE
4
o
FRESH
ACUTE
CRITERIA
FRESH
CHRONIC
CRfTERIA
SALTWATER
ACUTE
CRfTERIA
SALTWATER
CHRONIC
CRITERIA
HUMAN HEALTH (10-6 RISK LEVEL FOR CARCINOGENS)
PUBLISHED CRITERA
RECALCULATED VALUES
using IRIS, as of 9/90
WATER &
ORGANISMS
ORGANISMS
ONLY
WATER &
ORGANISMS
ORGANISMS
ONLY
DRINKING
WATER MCL
CRITERIA
FEDERAL
REGISTER
NOTICE
SOLIDS DISSOLVED
AND SALINITY — N N 250,000. RB
SOLIDS SUSPENDED AND
TURBIDITY
N
N
NARRATIVE STATEMENT — SEE DOCUMENT
RB
STYRENE
100-42-5
N
Y
100.
SULFIDE-HYDROGEN
SULFIDE
7783-06-4
N
N
2.0
2.0
RB
TEMPERATURE
—
N
N
SPECIES DEPENDENT CRITERIA
— SEE DOCUMENT
RB
TETRACHLOROBENZENE,
1,2,4,5-
95-94-3
N
N
38.
48.
45 FR 79327
TETRACHLOROETHANE,
1,1,2,2-
79-34-5
Y
Y
*2,400.
*9,020.
0.17
10.7
0.17
11.
57 FR 60912
TETRACHLOROETHANES
25322-20-7
Y
N
*9,320
45 FR 79328
TETRACHLOROETHYLENE
127-18-4
Y
Y
*5,280
*840.
*10,200.
*450.
0.8
8.85
5.0
45 FR 79340
TETRACHLOROPHENOL,
2,3,5,6-
935-95-5
N
N
*440.
45 FR 79329
THALLIUM
7440-28-0
Y
N
*1,400.
*40.
*2,130.
13.
48.
1.7
6.3
57 FR 60913
TOLUENE
108-88-3
Y
N
*17,500.
*6,300.
*5,000.
14,300.
424,000.
6,800.
200,000.
1,000.
57 FR 60912
TOXAPHENE
8001-35-2
Y
Y
0.73
0.0002
0.21
0.0002
0.00071
0.00073
0.00073
0.00075
/p/5.0
57 FR 60915
TRICHLORINATED ETHANES
25323-89-1
Y
Y
*18,000.
45 FR 79328
TRICHLOROETHANE, 1,1,1-
71-55-6
Y
N
*31,200.
18,400.
1,030,000.
200.
57 FR 60848
TRICHLOROETHANE, 1,1,2-
79-00-5
Y
Y
*9,400.
0.6
41.8
0.60
42.
57 FR 60912
TRICHLOROETH YLEN E
79-01-6
Y
Y
*45,000.
*21,900.
*2,000.
2.7
80.7
2.7
81.
5.0
45 FR 79341
TRICHLOROPHENOL, 2,4,5-
95-95-4
N
N
/p/100
/p/63
/p/240
/p/11
2,600.
45 FR 79329
TRICHLOROPHENOL, 2,4,6-
88-06-2
Y
Y
*970.
1.2
3.6
2.1
6.5
57 FR 60912
VINYL CHLORIDE
75-01-4
Y
Y
2.0
525.
2.0
45 FR 79341
XYLENES
—
N
N
10,000.
—
ZINC 7440-66-6 Y N 120. + 110 + 95. 86. 52 FR 6214
+ = Hardness dependent criteria (100 mg/L CaC03 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 Y = Yes
*** = pH dependent criteria (7.8 pH used) N = No
MCL= Maximum contaminant level (only for listed chemicals) Marine 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 1992 for regulatory purposes.
-------
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) (DIOXIN) .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
-------
ACENAPHTHENE
83-32-9
CRITERIA
Aquatic Life The available data for acenaphthene indicate that acute toxicity to fresh-
water aquatic life occurs at concentrations as low as 1,700 ng/Land would
occur at lower concentrations among species that are more sensitive than
those tested. No data are available concerning the chronic toxicity of
acenaphthene to sensitive freshwater aquatic animals, but toxicity to fresh-
water 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 |^g/L.
Human Health Human health criteria were recalculated using Integrated Risk Information
System (IRIS) to reflect available data as of 12/92 (57 RR. 60890). Recalcul-
ated IRIS values for acenaphthene are 1,200 M-g/L for ingestion of
contaminated water and organisms and 2,700 fig/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.
1
-------
2
-------
ACROLEIN
107-02-8
CRITERIA
Aquatic Life 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 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 acrolein to
sensitive saltwater aquatic life.
Human Health 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 jig/L.
For the protection of human health from the toxic properties of acro-
lein ingested through contaminated aquatic organisms alone, the ambient
water criterion is 780 ng/L.
(45 F.R. 79318, November 28,1980)
See Appendix C for Human Health Methodology.
3
-------
ACRYLONITRILE
107-13-1
CRITERIA
Aquatic Life 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.
Human Health 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 lO"3,10"6, and 10"7.
Published human health criteria were recalculated using Integrated
Risk Information System (IRIS) to reflect available data as of 12/92. Recal-
culated IRIS values for acrylonitrile are 0.059 ng/L for ingestion of
contaminated water and organisms and 0.66 ng/L for ingestion of contam-
inated 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.
5
-------
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.
7
-------
*ALDRIN
309-00-2
CRITERIA
Aquatic Life Not to exceed 3.0 ng/L in fresh water or 1.3 ng/L in salt water.
For freshwater aquatic life, the concentration of aldrin should not ex-
ceed 3.0 jxg/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 exceed
1.3 ng/L at any time. No data are available concerning the chronic toxicity
of aldrin to sensitive saltwater aquatic life.
Human Health 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 fig/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
9
-------
10
-------
B
ALKALINITY
CRITERIA
20 mg/L, or more as CaCO^, for freshwater aquatic life except where natu-
ral concentrations are less!
Introduction 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 pollu-
tants 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.
Rationale 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 max-
imum 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. Components
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 minimum al-
kalinity 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 wa-
ters, 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
-------
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
ALKALINH Y
MG/L AS C'ACO,
Stcain generation boiler makeup
350
Steam generation cooling
500
Textile mill products
50-200
Paper and allied products
75-150
Chemical and allied products
500
Petroleum refining
500
Pnmarv metals industries
200
Food canninc industries
300
Bottled and canned soft drinks
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 car-
bonates in the soil water as the water becomes more concentrated through
evaporation and transpiration. As the calcium and magnesium ions de-
crease in concentration, the percentage of sodium increases and results in
soil and plant damage. Alkalinity may also lead to chlorosis in plants be-
cause it causes the iron to precipitate as a hydroxide. Hydroxyl ions react
with available iron in the soil water and make the iron unavailable to
plants. Such deficiencies induce chlorosis and further plant damage. Usu-
ally 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
-------
ALUMINUM
7429-90-5
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.
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
ceriodaphnids 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
Hg/L, respectively. The diatom, Cyclotella 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 ng/L
caused a 24 percent reduction in the growth of young brook trout and 174
(xg/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 ng/L
more than once every three years on the average and if the one-hour aver-
age concentration does not exeed 750 ng/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
CRITERIA
Aquatic Life
Summary
-------
14
-------
AMMONIA
7664-41-7
SUMMARY
Fresh Water All concentrations used herein are expressed as un-ionized ammonia
(NH3) because NH3, not the ammonium ion (NH4+ ), has been demon-
stffteB 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 inverte-
brate 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/L NH3.
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
-------
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 Cen-
trarchidae). 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 cor-
rected for the presumed effects of temperature and pH, chronic toxicity
values also show no clear trend among groups of fish, the most sensitive
species including 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 am-
monia criterion appropriate for the protection of aquatic animals,
therefore, 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+ o nh3+h3o+
The total ammonia concentration is the sum of NH3 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 pKa, the negative log of
stoichiometric dissociation,
Equation 2
% UIA= 100 [1 + 10(pKa-pH)]-1
The stoichiometric dissociation constant is defined
Equation 3
[NHaUhT]
Ka " t
[NHa+ ]
where the brackets represent molal concentrations. Ka is a function of the
temperature and ionic strength of the solution.
16
-------
Whitfield (1974) developed theoretical models to determine the pKa 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,
Equation 5
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 pksa, 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/LNH3) (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 = 10°-O3(2O"TCAP) ; TCAPs Ts 30
10o.03(20-T) ; 0 s T s TCAP
*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
-------
Table 1.—One-hour average concentrations for ammonia with salmonids or other
sensitive coldwater species present.*
Temperature fC)
PH
0
5
10
15
20
25
30
Un-ionized Ammonia (mg/L NH3)
6.50
0.0091
0.0129
0.0182
0.026
0.036
0.036
0.036
6.75
0.0149
0.021
0.030
0.042
0.059
0.059
0.059
7.00
0.023
0.033
0.046
0.066
0.093
0.093
0.093
7.25
0.034
0.048
0.068
0.095
0.135
0.135
0.135
7.50
0.045
0.064
0.091
0.128
0.181
0.181
0.181
7.75
0.056
0.080
0.113
0.159
0.22
0.22
0.22
8.00
0.065
0.092
0.130
0.184
0.26
0.26
0.26
8.25
0.065
0.092
0.130
0.184
0.26
0.26
0.26
8.50
0.065
0.092
0.130
0.184
0.26
0.26
0.26
8.75
0.065
0.092
0 130
0.184
0.26
0.26
0.26
9 00
0.065
0.092
0.130
0.184
0.26
0.26
0.26
Total Ammonia (
mg/L NH3)
6.50
35
33
31
30
29
20
14.3
6.75
32
30
28
27
27
18.6
13.2
7.00
28
26
25
24
23
16.4
11.6
7.25
23
22
20
19.7
19.2
13 4
9.5
7.50
17.4
16.3
15.5
14.9
14.6
10.2
7.3
7.75
12.2
11.4
10.9
10.5
10.3
7.2
5.2
8.00
8 0
7.5
7.1
6.9
6.8
4.8
3.5
8.25
4.5
4.2
4.1
4.0
3.9
2.8
2.1
8.50
2.6
24
2.3
2.3
2.3
1.71
1.28
8.75
1 47
1 40
1.37
1.38
1.42
1.07
0.83
9.00
0.86
0.83
0.83
0.86
0.91
0.72
0.58
*To convert these values to mg/L N, multiply by 0.822.
FPH = 1 8 s pH s 9
1 + 107'4 ~ pH
1.25 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 7.7 £ pH £ 9
107.7 -pH
= 20 • — nU 6.5 £ pH £ 7.7
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.
-------
Table 2.—One-hour average concentrations for ammonia with saimonids or other
sensitive coldwater species absent.
*
Temperature (*C)
PH
0
5
10
15
20
25
30
Un-ionized Ammonia (mg/L NH3)
6.50
0.0091
0.0129
0.0182
0.026
0.036
0.051
0.051
6.75
0.0149
0.021
0.030
0.042
0.059
0.084
0.084
7.00
0.023
0.033
0.046
0.066
0.093
0.131
0.131
7.25
0.034
0.048
0.068
0.095
0.135
0.190
0.190
7.50
0.045
0.064
0.091
0.128
0.181
0.26
0.26
7.75
0.056
0.080
0.113
0.159
0.22
0.32
0.32
8.00
0.065
0.092
0.130
0.184
0.26
0.37
0.37
8.25
0.065
0.092
0.130
0.184
0.26
0.37
0.37
8.50
0.065
0.092
0.130
0.184
0.26
0.37
0.37
8.75
0.065
0.092
0.130
0 184
0.26
0.37
0.37
9.00
0.065
0.092
0.130
0.184
0.26
0.37
0.37
Total Ammonia (mg/L NH3)
6.50
35
33
31
30
29
29
20
6.75
32
30
28
27
27
26
18.6
7.00
28
26
25
24
23
23
16.4
7.25
23
22
20
19.7
19.2
19.0
13.5
7.50
17.4
16.3
15.5
14.9
14.6
14.5
10.3
7.75
12.2
11.4
10.9
10.5
10.3"
10.2
7.3
8.00
8.0
7.5
7.1
6.9
6.8
6.8
4.9
8.25
4.5
4.2
4.1
4.0
3.9
4.0
2.9
8 50
2.6
2.4
2.3
2.3
2.3
2.4
1 81
8.75
1.47
1 40
1.37
1.38
1 42
1.52
1.18
9.00
0.86
0.83
0 83
0.86
0.91
1.01
0.82
*To convert these values to mg/L N, multiply by 0.822.
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. De-
velopment 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
-------
Table 3.—Four-day average concentrations for ammonia with salmonids or other
sensitive coidwater species present.*
Temperature fC)
pH
0
5
10
15
20
25
30
Un-ionized Ammonia (mg/L NH3)
6.50
0.0008
0.0011
0.0016
0.0022
0.0022
0.0022
0.0022
6.75
0.0014
0.0020
0.0028
0.0039
0.0039
0.0039
0.0039
7.00
0.0025
0.0035
0.0049
0.0070
0.0070
0.0070
0.0070
7.25
0.0044
0.0062
0.0088
0.0124
0.0124
0.0124
0.0124
7.50
0.0018
0.0111
0.0156
0.022
0.022
0.022
0.022
7.75
0.0129
0.0182
0.026
0.036
0.036
0.036
0.036
8.00
0.0149
0.021
0.030
0.042
0.042
0.042
0.042
8.25
0.0149
0.021
0.030
0.042
0.042
0.042
0.042
8.50
0.0149
0.021
0.030
0.042
0.042
0.042
0.042
8.75
0.0149
0.021
0.030
0.042
0.042
0.042
0.042
9 00
0.0149
0.021
0.030
0.042
0 042
0.042
0 042
Total Ammonia (mg/L NH3)
6.50
3.0
2.8
27
2.5
1 76
1.23
0.87
6 75
3.0
2.8
2.7
2.6
1 76
1.23
0.87
7.00
3 0
2.8
2 7
2.6
1.76
1.23
0.87
7.25
3.0
2.8
2.7
2.6
1.77
1.24
0.88
7.50
3.0
2.8
2.7
2.6
1.78
1.25
0.89
7.75
2.8
2.6
2.5
24
1.66
1.17
0.84
8.00
1.82
1.70
1.62
1.57
1.10
0.78
0.56
8.25
1.03
0.97
0.93
0.90
0.64
0.46
0.33
8.50
0.58
0.55
0.53
0.53
0.38
0.28
0.21
8.75
0.34
0.32
0.31
0.31
0.23
0.173
0.135
9.00
0.195
0.189
0.189
0.195
0.148
0.116
0.094
*To convert these values to mg/L N, multiply by 0.822.
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 1Q10 for
Criterion Maximum Concentration design flow and 7Q5 or 7Q10 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.
-------
Table 4.—Four-day average concentrations for ammonia with salmonids or other
sensitive coldwater species absent* **
Temperature f C)
PH
0
5
10
15
20
25
30
Un-ionized Ammonia (mg/L NH3)
6.50
0.0008
0.0011
0.0016
0.0022
0.0031
0.0031
0.0031
6.75
0.0014
0.0020
0.0028
0.0039
0.0055
0.0055
0.0055
7.00
0.0025
0.0035
0.0049
0.0070
0.0099
0.0099
0.0099
7.25
0.0044
0.0062
0.0088
0.0124
0.0175
0.0175
0.0175
7.50
0.0078
0.0111
0.0156
0.022
0.031
0.031
0.031
7.75
0.0129
0.0182
0.026
0.036
0.051
0.051
0.051
8.00
0.0149
0.021
0.030
0.042
0.059
0.059
0.059
8.25
0.0149
0.021
0.030
0.042
0.059
0.059
0.059
8.50
0.0149
0.021
0.030
0.042
0.059
0.059
0.059
8.75
0.0149
0.021
0.030
0.042
0.059
0.059
0.059
9.00
0.0149
0.021
0.030
0.042
0.059
0.059
0.059
Total Ammonia (mg/L NH3)
6.50
3.0
2.8
2.7
2.5
2.5
1.73
1.23
6.75
3.0
2.8
2.7
2.6
2.5
1.74
1.23
7.00
3.0
2.8
2.7
2.6
2.5
1.74
1.23
7.25
3.0
2.8
2.7
2.6
2.5
1.75
1.24
7.50
3.0
2.8
2.7
2.6
2.5
1.76
1.25
7.75
2.8
2.6
2.5
2.4
2.3
1.65
1.18
8.00
1.82
1.70
1.62
1.57
1.55
1.10
0.79
8.25
1.03
0.97
0.93
0.90
0.90
0.64
0.47
8.50
0.58
0.55
0.53
0.53
0.53
0.39
0.29
8.75
0.34
0.32
0.31
0.31
0.32
0.24
0.190
9.00
0.195
0.189
0.189
0.195
0.21
0.163
0.133
*To convert t
••These valu
recommends
hese values to mg/L N, multiply by 0.82Z
bs may be conservative; however, if a more refined criterion is desired, EPA
a site-specific criteria modification.
These matters are discussed in more detail in EPA's "Technical Support
Document for Water Quality-Based Toxics Control."
Salt 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, 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/Lmore 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 ani-
mals appear to have narrow range of acute susceptibilities to ammonia, this
criterion will probably be as protective as intended only when the magni-
tudes 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
Hampson's (1977) program of Whitfield's (1974) model for hydrolysis of
ammonium ions in sea water (see original document).
21
-------
Table 5.—Water quality criteria for saltwater aquatic life based on total ammonia (mg/L).
Criteria Maximum Concentrations
Temperature (*C)
PH
0
5
10
15
20
25
30
35
Salinity =
lOg/kg
7.0
270
191
131
92
62
44
29
21
7.2
175
121
83
58
40
40
19
13
7.4
110
77
52
35
25
25
12
8.3
7.6
69
48
33
23
16
16
7.7
5.6
7.8
44
31
21
15
10
10
5.0
3.5
8.0
27
19
13
9.4
6.4
6.4
3.1
2.3
8.2
18
12
8.5
5.8
4.2
4.2
2.1
1.5
8.4
11
7.9
5.4
3.7
2.7
2.7
1.4
1.0
8.6
7.3
5.0
3.5
2.5
1.8
1.8
0.98
0.75
8.8
4.6
3.3
2.3
1.7
1.2
1.2
0.71
0.56
9.0
2.9
2.1
1.5
1.1
0.85
0.85
0.52
0.44
Salinity =
20 g/kg
7.0
291
200
137
96
64
44
31
21
7.2
183
125
87
60
42
29
20
14
7.4
166
79
54
37
27
18
12
8.7
7.6
73
50
35
23
17
11
7.9
5.6
7.8
46
31
23
15
11
7.5
5.2
3.5
8.0
29
20
14
9.8
6.7
4.8
3.3
2.3
8.2
19
13
8.9
6.2
4.4
3.1
2.1
1.6
8.4
12
8.1
5.6
4.0
2.9
2.0
1.5
1.1
8.6
7.5
5.2
3.7
2.7
1.9
1.4
1.0
0.77
8.8
4.8
3.3
2.5
1.7
1.3
0.94
0.73
0.56
9.0
3.1
2.3
1.6
1.2
0.87
0.69
0.54
0.44
Salinity =
30 g/kg
7.0
312
208
148
102
71
48
33
23
7.2
196
135
94
64
44
31
21
15
7.4
125
85
58
40
27
19
13
9.4
7.6
79
54
37
25
21
12
8.5
6.0
7.8
50
33
23
16
11
7.9
5.4
3.7
8.0
31
21
15
10
7.3
5.0
3.5
2.5
8.2
20
14
9.6
6.7
4.6
3.3
2.3
1.7
8.4
12.7
8.7
6.0
4.2
2.9
2.1
1.6
1.1
8.6
8.1
5.6
4.0
2.7
2.0
1.4
1.1
0.81
8.8
5.2
3.5
2.5
1.8
1.3
1.0
0.75
0.58
9.0
3.3
2.3
1.7
1.2
0.94
0.71
0.56
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
-------
Table 6.-
-Water quality criteria for saltwater aquatic life based on total ammonia (mg/L).
Criteria Continuous Concentrations
Temperature (*C)
PH
0
5
10
15
20
25
30
35
Salinity =
10 g/kg
7.0
41
29
20
14
9.4
6.6
4.4
3.1
7.2
26
18
12
8.7
5.9
4.1
2.8
2.0
7.4
17
12
7.8
5.3
3.7
2.6
1.8
1.2
7.6
10
7.2
5.0
3.4
2.4
1.7
1.2
0.84
7.8
6.6
4.7
3.1
2.2
1.5
1.1
0.75
0.53
8.0
4.1
2.9
2.0
1.4
0.97
0.69
0.47
0.34
8.2
2.7
1.8
1.3
0.87
0.62
0.44
0.31
0.23
8.4
1.7
1.2
0.81
0.56
0.41
0.29
0.21
0.16
8.6
1.1
0.75
0.53
0.37
0.27
0.20
0.15
0.11
8.8
0.69
0.50
0.34
0.25
0.18
0.14
0 11
0.08
9.0
0.44
0.31
0.23
0.17
0.13
0.10
0.08
0.07
Salinity =
20 g/kg
7.0
44
30
21
14
9.7
6.6
4.7
3.1
7.2
27
19
13
9.0
6.2
4.4
3.0
2.1
7.4
18
12
8.1
5.6
4.1
2.7
1.9
1.3
7.6
11
7.5
5.3
3.4
2.5
1.7
1.2
0.84
7.8
6.9
4.7
3.4
2.3
1.6
1.1
0.78
0.53
8.0
4.4
3.0
2.1
1.5
1.0
0.72
0.50
0.34
8.2
2.8
1.9
1.3
0.94
0.66
0.47
0.31
0.24
8.4
1.8
1.2
0.84
0.59
0.44
0.30
0.22
0.16
8.6
1.1
0.78
0.56
0.41
0.28
0.20
0,15
0.12
8.8
0.72
0.50
0.37
0.26
0.19
0.14
0.11
0.08
9.0
0.47
0.34
0.24
0.18
0.13
0.10
0.08
0.07
Salinity =
30 g/kg
7.0
47
31
22
15
11
7.2
5.0
3.4
7.2
29
20
14
9.7
6.6
4.7
3.1
2.2
7.4
19
13
8.7
5.9
4.1
2.9
2.0
1.4
7.6
12
8.1
5.6
3.7
3.1
1.8
1.3
0.90
7.8
7.5
5.0
3.4
2.4
1.7
1.2
0.81
0.56
8.0
4.7
3.1
2.2
1.6
1.1
0.75
0.53
0.37
8.2
3.0
2.1
1.4
1.0
0.69
0.50
0.34
0.25
8.4
1.9
1.3
0.90
0.62
0.44
0.31
0.23
0.17
8.6
" 1.2
0.83
0.59
0.41
0.30
0.22
0.16
0.12
8.8
0.78
0.53
0.37
0.27
0.20
0.15
0.11
0.09
9.0
0.50
0.34
0.26
0.19
0.14
0.11
0.08
0.07
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.
Implementation 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 temper-
ature compensation probe provided temperature correction. Note that the
responsiveness of a new electrode may be enhanced by holding it in sea-
water 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 mea-
surements. 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 measuring pH,
the sample was initially gently agitated or stirred to assure good mixing at
the electrode tip but without entraining air bubbles in the sample. 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/minute before re-
cording. Following each measurement, the electrode was rinsed with sea
water and placed in fresh sea water for the temporary storage 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
7440-36-0
CRITERIA
Aquatic Life 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.
Human Health 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
7440-38-2
CRITERIA
Aquatic Life Arsenic (III) — Freshwater — 1-hour average of 360 ng/L
4-day average of 190 ng/L
Saltwater — 1-hour average of 69 ng/L
4-day average of 36 ng/L
Summary 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
Hg/L for a cladoceran to 97,000 n-g/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 ng/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 toxicological 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 ng/L
was obtained in a test on inorganic arsenic (III) with embryos and toad
larvae.
Twelve species of saltwater animals have acute values for inorganic ar-
senic (III) from 232 to 16,030 ng/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 n-g/L. Arsenic (HI) and arsenic (V)
are equally toxic to various species of saltwater algae, but the sensitivities
of the species range from 19 M-g/L to more than 1,000 ng/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 (III) does not exceed 190 ng/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 ng/L more
than once every three years on the average and if the one-hour average
concentration does not exceed 69 ng/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 Hg/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 ng/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 n-g/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 maybe 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
-------
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
1Q10 for Criterion Maximum Concentration design flow and 7Q5 or 7Q10
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."
(50F.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 |xg/L for ingestion of con-
taminated water and organisms and 0.14 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) (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
-------
30
-------
ASBESTOS
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
-------
BACTERIA
CRITERIA
Bathing Waters
(Full Body Contact) 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).
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 or the other of the follow-
ing:*
E. coli 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
BEACHAREA
(UPPER 75%
MODERTE FULL
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
E. coli
33'
0)
126
61
235
78
298
107
409
151
575
* Only one indicator should be used. The regulatory agency should select the appropriate indicator for its conditions.
Marine Water
enterococci
NOTES:
19
35
(3)
104
158
276
501
(1) Calculated to nearest whole number using equation:
illness rate/1000 people + 6.28
(mean enterococci density) = antilog10 9 40
(2) Calculated to nearest whole number using equation:
illness rate/1000 people + 11.74
9.40
(mean E. coli density) = antilog 10
(3) Calculated to nearest whole number using equation:
(mean enterococci density) = antilog 10
(4) Single sample limit = antilog10
(log10 indicator geometric mean
density/100ml)
illness rate/1000 people - 0.20
12.17
x (log10 stand.
10 ¦
deviation)
-34
factor determined from areas
under the normal probability
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. coli 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.
-------
BARIUM
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 (BaS04) and witherite (BaC03), both highly insolu-
ble 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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BENZENE
71-43-2
CRITERIA
Aquatic Life 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 pig/L with a fish species exposed for 168 days.
Human Health 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 F.R. 60911). Recalculated IRIS values for benzene are 1.2 ng/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
-------
38
-------
BENZIDINE
92-87-5
CRITERIA
Aquatic Life 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.
Human Health 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 fxg/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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BERYLLIUM
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 ng/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)
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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BORON
CRITERION
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.
Introduction 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.
Rationale 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
boric 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
Ug/L, some sensitive plants such as citrus began to show injury. Water con-
taining 2 ug/L boron (with neutral and alkaline soils of high absorption
capacities) might be used for some time without injury to sensitive plants.
The criterion of 750 ng/L is thought to protect sensitive crops during long-
term irrigation.
(Quality Criteria for Water, July 1976) PB-263943
See Appendix D for Methodology.
45
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46
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D
CADMIUM
7440-43-9
CRITERIA
Aquatic Life Saltwater — 1-hour average of 43.0 ng/L
4-day average of 9.3 ^g/L
Freshwater criteria are hardness dependant. See text.
Criteria 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 ng/Lfor 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 ng/L for Daphnia magna to 156 |xg/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
Hg/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 ng/L for larval Atlantic silverside to 114,000 ng/L for juvenile
mummichog. Acute values for 30 species of invertebrates range from
15.5 fig/L for a mysid to 135,000 ng/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 sim-
ilar chronic values of 82 and 7.1 |xg/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 fig/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 ng/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 |xg/L) of cadmium does not exceed the numerical value given by
g(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 (ig/L) does not exceed the numerical value given
by
(1.128 [In (hardness)]-3.828)
c
more than once every three years on the average. For example, at
hardnesses of 50, 100, and 200 mg/L as CaCC>3, the four-day average
concentrations of cadmium are 0.66, 1.1, and 2.0 |xg/L, respectively, and
the one-hour average concentrations are 1.8, 3.9, and 8.6 ng/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 ng/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 under protective 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
1Q10 for Criterion Maximum Concentration design flow and 7Q5 or 7Q10
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
56-23-5
CRITERIA
Aquatic Life 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.
Human Health 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 ng/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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CHLORDANE
57-74-9
CRITERIA
Aquatic Life For chlordane, the criterion to protect freshwater aquatic life as derived
using the guidelines is 0.0043 n-g/L as a 24-hour average. The concentra-
tion should not exceed 2.4 pig/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.
Human Health 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 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. 60914, December 22,1992)
See Appendix B for Aquatic Life Methodology.
See Appendix C for Human Health Methodology.
51
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CHLORIDE
16887-00-6
CRITERIA
Aquatic Life 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 ng/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 fxg/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 |j.g/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
M-g/L for ingestion of contaminated aquatic organisms only.
Trichlorobenzenes
Because of insufficiency in the available information for the trichloro-
benzenes, 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 ng/L.
Pentachlorobenzene 608-93-5
For the protection of human health from the toxic properties of pen-
tachlorobenzene 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"6, and 10'7.
Published human health criteria were recalculated using IRIS to reflect
available data as of 12/92 (57 F.R. 609121, December 22,1992). The recal-
culated IRIS value for chlorinated benzenes is .00075 jig/L for ingestion of
contaminated water and organisms and 0.00077 ng/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
occurs at concentrations as low as 118,000 ng/L for 1,2-dichloroethane;
18,000 (ig/L for two trichloroethanes; 9,320 ng/L for two tetrachloro-
ethanes; 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 ng/L for 1,1,2-trichchloroethane; 2,400 ng/L for
1,1,2,2-tetrachloroethane; 1,100 n-g/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 (xg/L for 1,1,1-trichloroethane; 9,020
Hg/L for 1,1,2,2-tetrachloroethane; 390 ng/L for pentachloroethane; and
940 ng/L for hexachloroethane.
Chronic toxicity occurs at concentrations as low as 281 (ig/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 10'7.
Health criteria were recalculated using Integrated Risk Information
System (IRIS) to reflect available data as of 12/92 (57 F.R. 60848). Recalcul-
ated 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"6 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-
trichloroethane are 0.60 ng/L for ingestion of contaminated water and
organisms and 42 M-g/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- tetra-
chloroethane are 0.17 ng/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"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 hexachloro-
ethane 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 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 tox-
icity 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 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.
59
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60
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CHLORINATED PHENOLS
CRITERIA
Aquatic Life 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 |ig/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 pig/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 toxic-
ity generally increases with increasing chlorination and that acute toxicity
occurs at concentrations as low as 440 ng/L for 2,3,5,6-tetrachlorophenol
and 29,700 jig/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.
Human Health
3-Chlorophenol
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
human 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 M-g/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.
2,3-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 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 do not have a demonstrated relationship to potentially ad-
verse effects on human health.
61
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2.5-Dichlorophenol
Sufficient data are not available for 2,5-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 0.5 M-g/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.
2.6-Dichlorophenol
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.
3,4-Dichlorophenol
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 p.g/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 fig/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.
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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 ng/L.
Organoleptic 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.
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 ng/L.
Organoleptic 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.
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
H-g/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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CHLORINE
7782-50-5
Freshwater — 4-day average of 11 ng/L
1-hour average of 19 ng/L
Saltwater — 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 |xg/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 M-g/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 con-
ducted 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 ^g/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 ex-
ceed 7.5 ng/L more than once every three years on the average, and if the
one-hour average concentration does not exceed 13 (xg/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
outfalls occur in a limited area — would be expected to require more time
CRITERIA
Aquatic Life
Summary
65
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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 1Q10 for
Criterion Maximum Concentration design flow and 7Q5 or 7Q10 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.
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CHLOROALKYLETHERS
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 jig/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 Information
System (IRIS) to reflect available data as of 12/92 (57 F.R. 60848). Recalcul-
ated IRIS values for bis(2-chloroisopropyl) ether are 1,400 M-g/L for
ingestion of contaminated water and organisms and 170,000 ng/L for in-
gestion 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"5,10"6, and 10"7. The cor-
responding recommended criteria are 37.6 x 10"6 ng/L, and 0.376 x 10"6
M-g/L, respectively. If these estimates are made for consumption of aquatic
organisms only, excluding consumption of water, the levels are 18.4 x 10"3
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 jxg/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 ng/L,
1.36 |xg/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
67-66-3
CRITERIA
Aquatic Life 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
occur at lower concentrations among species that are more sensitive than
the three tested species. As indicated by 27-day LC50 values, chronic toxic-
ity 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.
Human Health 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"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 chloroform are 5.7 M-g/L for ingestion of con-
taminated water and organisms and 470 |ig/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
95-57-8
CRITERIA
Aquatic Life The available data for 2-chlorophenol indicate that acute toxicity to fresh-
water aquatic life occurs at concentrations as low as 4,380 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 2-chlorophenol to sensitive freshwater aquatic life, but flavor
impairment occurs in one species of fish at concentrations as low as
2,000 ng/L.
No saltwater organisms have been tested with 2-chlorophenol, and
therefore, no statement can be made concerning acute or chronic toxicity.
Human Health Human health criteria were recalculated using Integrated Risk Information
System (IRIS) to reflect available data as of 12/92 (57 F.R. 60890). Recalcul-
ated IRIS values for 2-chlorophenol are 120 ng/L for ingestion of
contaminated water and organisms and 400 (ig/L for ingestion organisms
only. According to available organoleptic data, the estimated level is 0.1
Hg/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
2,4-D 94-75-7; 2,4,5-TP 93-72-1
CRITERIA
2,4-D 100 jig/L for domestic water supply (health).
2,4,5-TP 10 ng/L for domestic water supply (health).
Rationale 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 herbicidal 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.
LOWEST LONG
TERM LEVELS
WITH MINIMAL OR
NO EFFECTS
CALCULATED MAXIMUM SAFE
LEVELS FROM ALL
SOURCES OF EXPOSURE
WATER
Compound
Species
me/kc/daya
Safely
facior(X)
mg/kg/day
mg/man/davb
9c ot
Safe level
AL
mg/lc
2,4-D ....
2.4,5-TP...
Rat
Dog
Rat
Dog
0.5
8.0
2.6
0.9
1/500
1/500
1/500
1/500
0.1
0.016
0.005
0.002
7.0
1.12"
0.35
0.14d
20
20
0.1
0.01
'Assume weight of rai = 0 3 kg and of dog = 10 tg. assume average daily food consumption of rat = 0 05 kg
and of dog = 0 2 kg
p Assume average weight of human jduii = 70 kg
v Assume average daily intake of water for man = 2 liters
dChosen as basis on which to derive AL
Table 1 illustrates the derivation of the criteria for the two
chlorophenoxy 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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CHLORPYRIFOS
2921-88-2
CRITERIA
Aquatic Life Freshwater— 4-day average of 0.041 ng/L
1-hour average of 0.083 ng/L
Saltwater — 4-day average of 0.0056 |xg/L
1-hour average of 0.011 ng/L
Summary The acute values for 18 freshwater species in 15 genera range from
0.11 n-g/L for an amphipod to greater than 806 fig/L for 2 fishes and a
snail. The bluegill is the most sensitive fish species with an acute value of
10 M-g/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
M-g/L for the Korean shrimp, Palaemon macrodactylus, to 1,911 M-g/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
LC50s range from 0.58 fig/L for striped bass to 520 M-g/L for gulf toadfish.
Fish larvae are more sensitive than other life stages. Growth of the mysid,
Mysidopsis bahia, was reduced at 0.004 fig/Lin 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 M-g/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 fig/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 M-g/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
on the average, and if the one-hour average concentration does not exceed
0.083 M-g/L more than once every three years on the average.
75
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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 |xg/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
wasteload allocation model. Dynamic models are preferred for the applica-
tion 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.
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CHROMIUM
CRITERIA
Aquatic Life Chromium (VI) Freshwater — 4-day average of 11 ng/L
1-hour average ofl6 ng/L
Saltwater — 4-day average of 50 ng/L
1-hour average of 1,100 ng/L
Summary
Chromium (VI) 7440-47-3
Acute toxicity values for chromium (VI) are available for freshwater ani-
mal species in 27 genera and range from 23.07 jxg/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 (ig/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 fxg/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 ^/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 jxg/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 ^/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 ng/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.
77
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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 (III) 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 ng/L for the mummichog. In
a chronic test, effects were not observed on a polychaete worm at 50,400
jxg/L at pH=7.9, but acute lethality occurred at pH=4.5. Bioconcentration
factors for saltwater organisms and chromium (HI) range from 86 to 153,
similar to the bioconcentration factors for chromium (VI) and saltwater
species.
NATIONAL CRITERIA
Aquatic Life
Chromium (VI)
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 jig/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.
Chromium (III)
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 ng/L) of chromium (III) does not exceed the nu-
merical value given by
e(0.8190[ln(hardness)]+1.561)
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(0.8190[ln (hardness)]+3.688)
more than once every three years on the average. For example, at
hardnesses of 50, 100, and 200 mg/L as CaC03, 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 IQIO for Criterion Maximum
Concentration design flow and 7Q5 or 7Q10 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
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.
Introduction
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
25
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, poly-
hydroxyl 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
81
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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.
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*COPPER
7440-50-8
CRITERIA
Aquatic Life Not to exceed 2.9 jig/Lin 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
M-g/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
Hg/L for brook trout to 60.36 ng/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 fig/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 ng/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 M-g/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 |xg/L) of
copper does not exceed the numerical value given by
g(0.8545[ln(hardness)]-1.465)
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(0.9422pn(hardness)]-1.464)
•Indicates suspension, cancelation, or restriction by U.S. EPA Office of Pesticides and
Toxic Substances.
83
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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 CaCO3, 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 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 one-
hour average concentration of copper does not exceed 2.9 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 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 1Q10 for
Criterion Maximum Concentration design flow and 7Q5 or 7Q10 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 Information
System (IRIS) to reflect available data as of 12/92 (57 F.R. 60890). The recal-
culated IRIS values for copper is 1,300 n-g/L for ingestion of contaminated
water and organisms. Using available organoleptic data, the estimated
level is 1 mg/L for controlling undesirable taste and odor quality of ambi-
ent water. Organoleptic data as a basis for establishing a water quality
criteria have limitations and no demonstrated relationship to potentially
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.
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CYANIDE
57-12-5
Freshwater— 4-day average of 52 ng/L
1-hour average of 22 fig/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 |xg/L to 2,490 ng/L, but all of the
species with acute sensitivities above 400 ^g/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 ng/L, respectively. Chronic values for two fresh-
water invertebrate species were 18.33 and 34.06 ng/L. Freshwater plants
were affected at cyanide concentrations ranging from 30 ng/L to 26,000
M-g/L-
Free cyanide's acute toxicity to saltwater species ranged from 4.893
jig/L 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 [ig/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 ng/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 cri-
teria 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-
stressed system to recover from a pollution event in which exposure to
85
CRITERIA
Aquatic Life
Summary
-------
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 1Q10 for Criterion Maximum
Concentration design flow and 7Q5 or 7Q10 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 (ig/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
72-54-8
CRITERIA
Aquatic Life 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.
DDT 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 [ig/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.
TDE 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 |xg/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.
DDE The available data for DDE indicate that acute toxicity to freshwater
aquatic life occurs at concentrations as low as 1,050 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
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.
Human Health The ambient water concentration should be zero, based on the non-
threshold 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 organ-
isms. 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).
The recalculated IRIS value for DDT is 0.00059 ng/L for both ingestion of
water and organisms, and ingestion of contaminated aquatic organisms
only. IRIS values are based on a 10"6 risk level for carcinogens.
87
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The recalculated IRIS value for TDE 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 B for Aquatic Life Methodology.
See Appendix C for Human Health Methodology.
88
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DEMETON
8065-48-3
CRITERIA
Aquatic Life 0.1 M-g/L for both freshwater and saltwater aquatic life.
Rationale 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 M-g/L to 15,000 fig/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 ^g/L were the most sensitive fish.
Acute toxicity values reported for invertebrates range from 10 to 100,000
M-g/L.*
Static LC50 data for invertebrate Gammarus fasciatus yield 24- and 96-
hour LC50 values of 500 fig/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 ng/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.
89
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90
-------
DICHLOROBENZENES
25321-22-6
CRITERIA
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 recalcul-
ated using the Integrated Risk Information System (IRIS) to reflect
available information as of 12/92 (57 F.R. 60848). The recommended cri-
teria are 2,700 (ig/L for ingestion of contaminated water and organisms
and 17,000 |xg/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 |xg/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 (ig/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.
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 [ig/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.
-91
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92
-------
DICHLOROBENZIDINE
91-94-1
CRITERIA
Aquatic Life 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.
Human Health 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 F.R. 60848).
Recalculated IRIS values for 3,3-dichlorobenzidine are 0.04 fig/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"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.
93
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DICHLOROETHYLENES
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 |xg/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 fig/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"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 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-
dichloroethylene are 700 pig/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.
95
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2,4-DICHLOROPHENOL
120-83-2
CRITERIA
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-
dichlorophenol, and therefore, no statement can be made concerning acute
or chronic toxicity.
Human Health Human health criteria were recalculated using Integrated Risk Information
System (IRIS) to reflect available data as of 12/92 (57 F.R. 60848). Recalcul-
ated IRIS values for 2,4-dichlorophenol are 93.0 ng/L for ingestion of
contaminated water and organisms and 790 ng/L for ingestion of contami-
nated aquatic organisms only.
Aquatic Life
(45 F.R. 79318, November 28,1980) (57 F.R. 60848, December 22,1992)
See Appendix C for Human Health Methodology.
97
-------
98
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DICHLOROPROPANE
26638-19-7
DICHLOROPROPENE
26952-23-8
CRITERIA
Aquatic Life 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 ng/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 fig/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 Human health criteria were recalculated using Integrated Risk Information
System (IRIS) to reflect available data as of 12/92 (57 F.R. 60890). Recalcul-
ated IRIS values for 1,2-dichloropropane is 0.52 jig/L per ingestion 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
dichloropropenes ingested through water and contaminated aquatic or-
ganisms, the ambient water criterion is 87 ng/L.
For the protection of human health from the toxic properties of
dichloropropenes 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.
99
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100
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DIELDRIN
60-57-1
CRITERIA
Aquatic Life Freshwater— 24-hour average of 0.0019 ng/L
Never to exceed 2.5 ng/L
Saltwater — 24-hour average of 0.0019 |xg/L
Never to exceed 0.71 n-g/L
To protect freshwater aquatic life, the criterion for dieldrin is 0.0019
M-g/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 jig/L as a 24-hour average. The concentration should
not exceed 0.71 ng/L at any time.
Human Health 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 carcin-
ogens.
(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.
101
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102
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2,4-DIMETHYLPHENOL
105-67-9
CRITERIA
Aquatic Life 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 Human health criteria were recalculated using Integrated Risk Information
System (IRIS) to reflect data available as of 12/92 (57 F.R. 60890). Recalcul-
ated IRIS values for 2,4-dimethylphenol are 540 ng/L for ingestion of
contaminated water and organisms and 2,300 |xg/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.
103
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104
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DINITROTOLUENE
25321-14-6
CRITERIA
Aquatic Life
Human Health
-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 ptg/L, 0.11 ng/L, and 0.011 |xg/L,
respectively. If these estimates are made for consumption of aquatic organ-
isms only, excluding consumption of water, the levels are 91 ng/L, 9.1
|xg/L, and 0.91 ng/L, respectively.
(45 F.R. 79318, November 28,1980)
See Appendix C for Human Health Methodology.
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 fxg/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 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
dinitrotoluenes to sensitive saltwater aquatic life but a decrease in algal
cell numbers occurs at concentrations as low as 370 ng/L.
105
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106
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DIPHENYLHYDRAZINE
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"5,10'6, and 10"7. 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 [ig/L, 0.56
(ig/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
Hg/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.
107
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108
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DI-2-ETHYLHEXYL PHTHALATE
117-81-7
CRITERIA
Aquatic Life 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 2,100 ^ig/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 sl60 ng/L. An
ecosystem process, ammonia flux, has been shown to be reduced at
15.5 n-g/L in summer months.
Human Health Refer to phthalate esters.
109
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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 re-
search 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)
*Notc: These are water column concentrations recommendtd 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
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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 sev-
eral 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 proba-
bly 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
DISSOLVED OXYGEN (MG/L)
DAILY MAX DAILY M1N
DAILY MEAN
1
9.0
7.0
8.0
2
10.0
7.0
8.5
3
11.0
8.0
9.5"
4
12.03
8.0
9.5
5
10.0
8.0
9.0
6
11 0
9.0
10.0
7
12.0a
10.0
10.5C
57.0
65.0
1-day Minimum
7.0
7-day Mean Minimum
8.1
7-Hav Mean
9.3
"Above air saturation concentration (assumed to be 11 0 mg/L Tor Hits example)
b(1l 0 + 8.0)2
<(1! 0 + 10.0)2
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
113
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mortality or other adverse effects (e.g., through disease), the criteria are de-
signed to prevent significant episodes of continuous or regularly recurring
exposures to dissolved oxygen concentrations at or near the lethal thresh-
old. 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 lim-
its 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 cri-
teria 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 occurs.
Evaluation of an event's significance must be largely case- and site-
specific. 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
magnitude of an event must be a function of the spatial and temporal fre-
quency 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
of return period may be decided on a site-specific basis, taking into ac-
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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 Manipuiatable 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 minimum
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 apprecia-
bly 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 manipuiatable 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 manipuiatable 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 warmwater fish. Such decisions could be
site-specific based upon the extent of control and serial correlation.
(51F.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
115-29-7
CRITERIA
Aquatic Life 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 (ig/L at any time.
The criterion to protect saltwater aquatic life as derived using the
guidelines is 0.0087 n-g/L as a 24-hour average; the concentration should
not exceed 0.034 ng/L at any time.
Human Health Human health criteria were recalculated using Integrated Risk Information
System (IRIS) to reflect available data as of 12/92 (57 F.R. 60848). Recalcu-
late IRIS values for alpha-endosulfan, beta-endosulfan and endosulfan
sulfate are 0.93 ng/L for ingestion of contaminated water and organisms
and 2.0 n-g/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
72-20-8
CRITERIA
Aquatic Life 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 pig/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 Human health criteria were recalculated using Integrated Risk Information
System (IRIS) to reflect available data as of 12/92 (57 F.R. 60848). Recalcul-
ated IRIS values for both endrin and endrin aldehyde are 0.76 M-g/L for
ingestion of contaminated water and organisms and 0.81 |o.g/L for inges-
tion 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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122
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ETHYLBENZENE
100-41-4
CRITERIA
Aquatic Life The available data for ethylbenzene indicate that acute toxicity to fresh-
water 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
toxicity 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 Human health criteria were recalculated using Integrated Risk Information
System (IRIS) to reflect available data as of 12/92 (57 F.R. 60848). Recalcul-
ated 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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124
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FLUORANTHENE
206-44-0
CRITERIA
Aquatic Life The available data for fluoranthene indicate that acute toxicity to fresh-
water 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 Human health criteria were recalculated using Integrated Risk Information
System (IRIS) to reflect available data as of 12/92 (57 F.R. 60848). Recalcul-
ated 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 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.
Rationale 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 (DO)
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 atmo-
spheric 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.
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GUTHION
86-50-0
CRITERIA
Aquatic Life .01 ng/L for freshwater and saltwater aquatic life.
Rationale Four-day LC50 values for fish exposed to the organophosphate pesticide
range from 4 to 4,270 ng/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 |ig/L to
0.5 |xg/L.
Organophosphate pesticides inhibit the enzyme acetylcholinesterase
(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 ng/L
to 22.0 ng/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 LC50s as low as 0.33
Hg/L.
A criterion level of 0.01 ng/L for guthion is based on the use of 0.1 as
an application factor, applied to the 96-hour LC50 of 0.1 (ig/L (for the am-
phipod, Gammarus) and a similar value of 0.3 (xg/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
M-g/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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132
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HALOMETHANES
The available data for halomethanes indicate that acute toxicity to freshwa-
ter aquatic life occurs at concentrations as low as 11,000 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
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 algal
cell numbers occurs at concentrations as low as 11,500 ng/L.
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 ng/L for ingestion of con-
taminated water and organisms and 360 fig/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 ng/L for ingestion of contaminated water and
organisms and 22 ng/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 ng/L for ingestion of contaminated water and organisms
and 1,600 ng/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,
CRITERIA
Aquatic Life
Human Health
133
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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.
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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 (CaC03).
The concept of hardness comes from water supply practices: it is mea-
sured 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
WATER DESCRIPTION
MG/L AS CACO,
0-75
soft
75-150
moderately hard
150-300
hard
300 and up
very hard
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 mea-
sured as alkalinity, the carbonate hardness is usually considered equal to
the alkalinity.
Rationale 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 helpful
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in evaluating previous studies. For most existing data, it is difficult to de-
termine whether toxicity of various metal ions is reduced because of the
formation of metallic hydroxides and carbonates caused by the associated
increases in alkalinity, or because of an antagonistic effect of one of the
principal cations contributing to hardness — e.g., calcium — or a combina-
tion 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 copper be-
tween hard and soft waters can be explained by the difference in alkalinity
rather than hardness. A review of the literature on toxicity presented 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 assume 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 comprise
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
MAXIMUM CONCENTRATION
MG/L AS CACO,
Electric utilities
5,000
Textile
120
Pulp and paper
475
Chemical
1,000
Petroleum
900
Primary metals
1,000
'Requirements for final use within e process may be essentially zero, whtch requires treatment for concentration
reductions
(Quality Criteria for Water, July 1976) PB-263943
See Appendix D for Methodology.
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HEPTACHLOR
76-44-8
CRITERIA
Aquatic Life 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.
Human Health 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 RR. 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*6 risk level for carcin-
ogens.
Published human health criteria were recalculated using IRIS to reflect
available data as of 12/92 (57 RR. 60848). Recalculated IRIS values for hep-
tachlor epoxide are 0.00010 ng/L for ingestion of contaminated water and
organisms and 0.00011 M-g/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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138
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HEXACHLOROBENZENE
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
hexachlorobenzene has not been finalized.
Human Health Refer to Chlorinated Benzenes.
139
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140
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HEXACHLOROBUTADIENE
86-68-3
CRITERIA
Aquatic Life 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 ng/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.
Human Health 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 life-
time are estimated at 10'3,10"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 jxg/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.
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HEXACHLOROCYCLOHEXANE
58-89-9
CRITERIA
Aquatic Life
Gamma-hexachlorocyclohexane (Lindane) 58-89-9
For gamma-hexachlorocyclohexane (lindane), the criterion to protect fresh-
water 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 ng/L and would occur at lower concentrations among
species that are more sensitive than those tested. No data are available con-
cerning 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
H-g/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-hexachlorocyclohexane 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 10~5,10"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 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.
143
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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 recom-
mended criteria are 163 ng/L, 16.3 ng/L, and 1.63 ng/L, respectively. If
these estimates are made for consumption of aquatic organisms only, ex-
cluding 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-hexachlorocyclohexane (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
c. £. n
over a lifetime are estimated at 10" , 10 , and 10 . 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.
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HEXACHLOROCYCLOPENTADIENE
77-47-4
CRITERIA
Aquatic Life 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 Human health criteria were recalculated using Integrated Risk Information
System (IRIS) to reflect available data as of 12/92 (57 F.R. 60848)..Recalcul-
ated 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.
145
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146
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IRON
7439-89-6
CRITERIA
Aquatic Life 0.3 mg/L for domestic water supply (health).
1.0 mg/L for freshwater aquatic life.
Introduction 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 trivalent (Fe+++), 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 (Fe203) 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 set-
tled iron floes may have adverse effects on important benthic commercial
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. Precipitated 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 tobacco 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.
149
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150
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ISOPHORONE
78-59-1
CRITERIA
Aquatic Life 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
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 freshwater aquatic life.
The available data for isophorone indicate that acute toxicity to salt-
water 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 Human health criteria were recalculated using Integrated Risk Information
System (IRIS) to reflect available data as of 12/92 (57 F.R. 60848). Recalcul-
ated IRIS values for isophorone are 8.4 ng/L for ingestion of contaminated
water and organisms and 600 for ingestion of contaminated aquatic organ-
isms 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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LEAD
7439-92-1
Saltwater — 1-hour average of 220 |ig/L
4-day average of 8.5 |xg/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 M-g/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 ng/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 ng/L for the soft shell clam. A
chronic toxicity test was conducted with a mysid; unacceptable effects
were observed at 37 ng/L but not at 17 ng/L; the acute-chronic ratio for
this species is 124.8. A species of macroalgae was affected at 20 ng/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
M-g/L) of lead does not exceed the numerical value given by
_{1.273[1n (hardness)]-4.705)
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
_(1.273[ln(hardness)]- 1.460)
v
more than once every three years on the average. For example, at
hardnesses of 50, 100, and 200 mg/L as CaCC^ the four-day average
concentrations of lead are 1.3, 3.2, and 7.7 (xg/L, respectively, and the
one-hour average concentrations are 34, 82, and 200 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 lead does not exceed 8.5* ng/L more than
CRITERIA
Aquatic Life
Summary
153
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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 1Q10 for Crite-
rion Maximum Concentration design flow, and 7Q5 or 7Q10 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 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
121-75-5
CRITERIA
Aquatic Life 0.1 ng/L for freshwater and saltwater aquatic life.
Rationale Salmonids and centrarachids appear to be the most sensitive freshwater
fish to malathion. Documented 96-hour LC50s ranged from 120 to 265
Hg/L for four different salmonid species and 101 to 285 ng/L for three spe-
cies of centrarchids. Reported 96-hour LC50s for rainbow trout
(Onchorhynchus mykiss), largemouth bass (Micropterus salmoides), and
chinook salmon, (Onchorhynchus tshawytcha) were 86, 50, and 28 ng/L, re-
spectively.
Freshwater invertebrates are generally even more sensitive to mala-
thion than fish. Reported 96-hour LC50s for amphipod Gammarus lacustris
and G. fasciutus were 1.0 and 0.76 ng/L, respectively. The 48-hour LC50s
for the cladocerans Simocephalus serrulatus and Daphnia pulex ranged from
1.8 to 3.5 n-g/L, while the 24-hour LC50s for two midge larvae species aver-
aged just over two ng/L in tests with malathion.
In flow-through exposures to malathion with saltwater fish (Lagodon
rhombides), 575 ]u.g/L result in a 50 percent mortality rate in 3.5 hours and
caused about 75 percent brain acetylcholinesterase (AChE) inhibition. Sim-
ilar mortality and AChE inhibition is documented with other saltwater fish
as well. Static 96-hour tests for saltwater teleosts exposed to malathion in-
dicates a broad spectrum of species sensitivities, with LC50 values ranging
from 27 to 3,250 jig/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 LC50s ranging from 33 ng/L for sand shrimp
(Crangon septemspinosa) to 83 |i.g/L for the hermit crab (Pagurus
longicorpus).
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 ng/L, yielding a criterion of 0.1ng/L.
(Quality Criteria for Water, July 1976) PB-263943
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MANGANESE
7439-96-5
CRITERIA
50 ng/L for domestic water supply (health).
100 (xg/L for protection of consumers of saltwater molluscs.
Introduction 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
(Mn02), 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.
Rationale 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 toxicity
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 ng/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
157
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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 ng/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 lim-
ing 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 se-
lect areas and where acidophilic crops are cultivated and irrigated, a
criterion of 200 |xg/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
7439-97-6
CRITERIA
Not to exceed 2.4 ng/L in fresh water or 2.1 jxg/L in salt water.
0.012 and 0.025 fig/L for freshwater and saltwater aquatic life, respectively.
AQUATIC LIFE
SUMMARY 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 ng/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 fig/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
M-g/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 ng/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 ac-
tivity 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
•Indicates suspension, cancelation, or restriction by U.S. EPA Office of Pesticides and
Toxic Substances.
159
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discharged 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 (Lepomis macrochirus)
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 Res-
idue 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 salt-
water 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 |xg/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 ng/L more than once every three years
on the average. If the four-day average concentration exceeds 0.025 ng/L
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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
1Q10 for Criterion Maximum Concentration design flow and 7Q5 or 7Q10
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 fresh-
water, 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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162
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METHOXYCHLOR
72-435
CRITERIA
100 ng/L for domestic water supply (health).
0.03 ng/L for freshwater and saltwater aquatic life.
Rationale 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 ng/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 fig/L was observed. Yellow perch (Perca
flavescens) exposed to 0.6 ng/L methoxychlor for 8 months exhibited re-
duced growth. The four-day LC50s 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 LC50s for aquatic invertebrates were as low as 0.61 (ig/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 methoxy-
chlor.
The data indicate that 0.1 ng/L methoxychlor would be just below the
chronic effect level for the fathead minnow and Vb 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 ng/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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164
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MIREX
2385-85-5
CRITERIA
0.001 jig/L for freshwater and saltwater aquatic life.
Rationale 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
blandingi 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 (xg/L mirex for 144 hours were dead.
Exposure to 5 ng/L for 6, 24, and 58 hours resulted in 26, 50, and 98 percent
mortality within the 10-day observation period in clean water. Several sim-
ilar experiments with other crayfish species revealed comparable mortality
levels in exposures to low levels of mirex. For Promcambarus hayi, mirex tis-
sue residue accumulations ranged from 940- to 27,210-fold above water
concentrations after 48-hour exposures to 0.1 and 0.5^g/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
M-g/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 M-g/L in summer, 0.06 ng/L in fall, and
0.09 M-g/L in winter, was observed.
Effects of mirex on estuarine and marine crustaceans were observed
after considerable time had elapsed, so that length of exposure is an
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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 ap-
plication factor of 0.01 to reasonable average of toxic effect levels as
summarized above, a recommended marine criterion of 0.001 ng/L results.
(Quality Criteria for Water, July 1976) PB-263943
See Appendix D for Methodology.
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NAPHTHALENE
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
fig/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 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 naphthalene to sensi-
tive 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.
167
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168
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NICKEL
7440-02-0
CRITERIA
Not to exceed 75 ng/L in salt water.
8.3 (xg/L for saltwater aquatic life.
Freshwater criteria are hardness dependent. See text.
Summary Acute values with 21 freshwater species in 18 genera range from 1,101
Hg/L for a cladoceran to 43,240 ng/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 M-g/L for Daphnia magna in soft water to 526.7 ng/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 ng/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
Hg/L for mysid juveniles to 1,100,000 |xg/L for juveniles and adults of a
clam. The acute values for the four species of fish range from 7,598 to
350,000 ng/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 pig/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.
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
nickel (in (ig/L) does not exceed the numerical value given by
e(0.8460[ln (hardness)]+l.1645)
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(0.8460[ln (hardness)]+3.3612)
more than once every three years on the average. For example, at
hardnesses of 50, 100, and 200 mg/L as CaC03, the four-day average
169
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concentrations of nickel are 88, 160, and 280 ng/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
wasteload allocation model. Dynamic models are preferred, but limited
data or other considerations might make their use impractical; therefore,
regulatory programs must rely on a steady-state model.
Human Health Human health criteria were recalculated using Integrated Risk Information
System (IRIS) to reflect available data as of 12/92 (57 F.R. 60911). Recalcul-
ated IRIS values for nickel are 610 ^g/L for ingestion of contaminated
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
14797-55-8
CRITERIA
10 mg/L nitrate nitrogen (N) for domestic water supply (health).
Introduction 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 protein-
aceous 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.
Rationale 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
171
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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. Methemoglobine-
mia symptoms and other toxic effects were observed when high nitrate
well waters containing pathogenic bacteria were fed to laboratory mam-
mals. Conventional water treatment has no significant effect on nitrate
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
98-95-3
CRITERIA
Aquatic Life The available data for nitrobenzene indicate that acute toxicity to fresh-
water aquatic life occurs at concentrations as low as 27,000 (ig/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 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 Human health criteria were recalculated using Integrated Risk Information
System (IRIS) to reflect available data as of 12/92 (57 F.R. 60848). Recalcul-
ated 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 fig/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.
173
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174
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NITROPHENOLS
CRITERIA
Aquatic Life The available data for nitrophenols indicate that acute toxicity to fresh-
water 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 nitro-
phenols to sensitive freshwater aquatic life but toxicity to one species of
algae occurs at concentrations as low as 150 |xg/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 nitro-
phenols 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 M-g/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 Information
System (IRIS) to reflect available data as of 12/92 (57 F.R. 60848). Recalcul-
ated 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.
175
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176
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NITROSAMINES
35576-91-1
CRITERIA
Aquatic Life The available data for nitrosamines indicate that acute toxicity to fresh-
water aquatic life occurs at concentrations as low as 5,850 ng/Land would
occur at lower concentrations among species that are more sensitive than
those tested. No data are available concerning the chronic toxicity of nitro-
samines 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"5,10"6, and 10"7. 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 ng/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"5,10"6, and 10"7, 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-nitrosodiphenylam-
ine are 5.0 ng/L for ingestion of contaminated water and organisms and
16.0 (xg/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-propylamine 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 ng/L for ingestion of contaminated
water and organisms and 1.4 ng/L for ingestion of contaminated aquatic
organism only.
178
(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 toxicity
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 im-
mediate death to a wide variety of organisms, illustrate the lethal toxicity
that may be attributed to oil pollution. Similarly, a gasoline spill in South
Dakota in November 1969 was reported to have caused immediate 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 com-
pounds 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 sol-
uble 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 reproduction
and do not lead to immediate death of the organism. Disruption of such
behavior apparently can result from petroleum product concentrations as
low as 10 to 100 ng/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 impor-
tant public health problems: (1) the tainting of edible, aquatic species, and
(2) the possibility of edible marine organisms incorporating the high boil-
ing, 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 jig/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, establish-
ing 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 con-
tinuous 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, non-
petroleum 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
-------
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 Rivers
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.
181
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182
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PARATHION
56-38-2
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
Hg/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 (ig/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 ng/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 fig/L
for the Korean shrimp, Palaemon macrodactylus, and 17.8 n-g/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 ng/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
M-g/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 resil-
iences of ecosystems and their abilities to recover differ greatly, however,
and site-specific allowed excursion frequencies may be established if ade-
quate justification is provided.
When developing water quality-based permit limits and for designing
waste treatment facilities, criteria must be based upon an appropriate
CRITERIA
Aquatic Life
Summary
183
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wasteload 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)
87-86-5
CRITERIA
Not to exceed 13.0 ng/L in salt water.
7.9 (ig/L for saltwater aquatic life.
Freshwater criteria are pH dependent. See text.
Summary 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 |xg/L for larval
common carp to 43,920 pig/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
being 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 ng/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 jig/L and the acute-
chronic ratio is 6.873. Unfortunately, no statistical analysis of the worm test
data is available.
The EC50s 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.
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
Hg/L) of pentachlorophenol does not exceed the numerical value given by
g[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 fig/L) does not exceed the numerical value given
by
g[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 ng/L, respectively, and the one-hour average concentrations
are 5.5,20, and 68 fig/L. At pH = 6.8, a pentachlorophenol concentration of
1.74 ng/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 (ig/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 resil-
iences of ecosystems and their abilities to recover differ greatly, however,
and site-specific allowed excursion frequencies may be established if ade-
quate justification is provided.
When developing water quality-based permit limits and designing
waste treatment facilities, criteria must be based upon an appropriate
wasteload 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 Information
System (IRIS) to reflect data available as of 12/92 (57 F.R. 60840). Recalcul-
ated IRIS values for pentachlorophenol are 0.28 ng/L for ingestion of
contaminated water and organisms and 8.2 ng/L for ingestion of contami-
nated aquatic organisms only.
Using available organoleptic data, the estimated level is 30 jig/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 = -Log10 (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 princi-
pal system regulating pH in natural waters is the carbonate system, which
is composed of carbon dioxide (CO2), carbonic acid (H2CO3), bicarbonate
ion (HC03), and carbonate ions (CO3). 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.
187
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188
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PHENOL
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 |ig/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 ng/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
7723-14-0
CRITERION
0.10 ng/L yellow (elemental) phosphorus for estuarine and saltwater
aquatic life.
Introduction Phosphorus in its elemental form is particularly toxic and subject to
bioaccumulation in much the same way as mercury. Phosphorus as phos-
phate, however, is one of the major nutrients required for plant nutrition
and essential for life. In excess of a critical concentration, phosphates stim-
ulate 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
human 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
wastewaters high in phosphates. Cropland, forestland, and idle and urban
land contribute varying amounts of phosphorus-diffused sources in drain-
age to watercourses: surface runoff of rainfall, effluent from tile lines, or
return flow from irrigation. Other contributing sources are cattle feedlots,
concentrations 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 fig/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 P4 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.
The criterion of 0.10 jxg/L elemental phosphorus for marine or estua-
rine waters in 1/10 of demonstrated lethal levels to important marine
organisms and of levels found to result in significant bioaccumulation.
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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 jig/L P
may interfere with coagulation in water treatment plants. When such con-
centrations exceed 25 ng/L at the time of the spring turnover on a
volume-weighted basis in lakes or reservoirs, they may occasionally stimu-
late 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 eutrophica-
tion.
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 |xg/L total P.
Most relatively uncontaminated lake districts are known to have surface
waters that contain from 10 to 30 ^/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
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
193
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Table 1.—Annual loadings.
MEAN DEPTH/HYDRAUUC
DETENTION TIME
(meters/year)
OLIGOTROPHY OR
PERMISSIBLE LOADING
(grams/meter^/year)
EUTROPHIC OR CRITICAL
LOADING
(grams/meter^/year)
0.5
0.07
0.14
1.0
0.10
0.20
2.5
0.16
0.32
5.0
0.22
0.45
7.5
0.27
0.55
10.0
0.32
0.63
25.0
0.50
1.00
50.0
0.71
1.41
75.0
0.87
1.73
100.0
1.00
2.00
Source: Vollenweider (1973).
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 for plant photosynthesis;
• 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.
(Quality Criteria for Water, July 1976) PB-263943
See Appendix D for Methodology.
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PHTHALATE ESTERS
CRITERIA
Aquatic Life The available data for phthalate esters indicate that acute and chronic tox-
icity to freshwater aquatic life occurs at concentrations as low as and
Hg/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 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
phthalate esters to sensitive saltwater aquatic life, but toxicity to one spe-
cies of algae occurs at concentrations as low as M-g/L.
Human Health Human health criteria were recalculated using Integrated Risk Information
System (IRIS) to reflect available data as of 12/92 (57 F.R. 60913). Recalcul-
ated IRIS values for diethyl phthalate are 23,000 ^ig/L for ingestion of
contaminated water and organisms and 120,000 ng/L for ingestion of con-
taminated 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
phthalate are 2,700 y.g/L for ingestion of contaminated water and organ-
isms 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-
ethylhexyl phthalate are 1.8 ng/L for ingestion of contaminated water and
organisms and 5.9 |Ag/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 |xg/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 |xg/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)
See Appendix C for Human Health Methodology.
195
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196
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POLYCHLORINATED BIPHENYLS (PCBs)
1336-36-3
CRITERIA
Not to exceed 2.0 ng/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.
Aquatic Life For polychlorinated biphenyls, the criterion to protect freshwater aquatic
life as derived using the guidelines is 0.014 (ig/L as a 24-hour average. This
concentration is probably too high because it is based on bioconcentration
factors measured in laboratory studies; however, field studies produce fac-
tors at least 10 times higher for fishes. The available data indicate that
acute toxicity to freshwater aquatic life probably will occur only at concen-
trations 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 bi-
phenyls as derived using the guidelines is 0.030 |xg/L as a 24-hour average.
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 criterion
should provide adequate protection against acute toxicity.
Human Health 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
Hg/L 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 The limited freshwater database, available mostly from short-term
bioconcentration studies with two compounds, does not permit a state-
ment concerning acute or chronic toxicity for polynuclear aromatic
hydrocarbons.
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.
Human Health 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 as-
sumption for this chemical. However, zero level may not be presently
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, 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.
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200
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SELENIUM
7782-49-2
CRITERIA
Not to exceed 20 ng/L in fresh water or 300 jig/L in salt water.
5.0 ng/L and 71 ng/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
after 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
jig/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 |xg/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 fig/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
7440-22-4
CRITERIA
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.
Aquatic Life For freshwater aquatic life, the concentration (in pig/L) of total recoverable
silver should not exceed the numerical value given by
(1.72[ln(hardness)]-6.52)
V
at any time. For example, at hardnesses of 50, 100, and 200 mg/L as
CaCC^ the concentration of total recoverable silver should not exceed 1.2,
4.1, and 13 M-g/U 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 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 Settleable and suspended solids should not reduce the depth of the com-
Aquatic Life pensation point for photosynthetic activity by more than 10 percent from
the seasonally established norm for aquatic life.
Introduction 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.
Rationale 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 Eu-
ropean Inland Fisheries Advisory Commission. This 1965 review identified
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.
Settleable materials that blanket the bottom of waterbodies damage the
invertebrate populations, block gravel spawning beds, and, if organic, re-
move 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 sal-
monids 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
7783-06-4
CRITERIA
2 (ig/L undissociated H2S for fish and other aquatic life in either fresh
water or salt water.
Introduction 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 pri-
marily as an anaerobic degradation product of both organic sulfur
compounds and inorganic sulfates. Sulfides are constituents of many in-
dustrial 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.
Rationale The degree of hazard exhibited by sulfide to aquatic animal life is depen-
dent 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 common
within the first 20 mm of water above this layer. Walleye (Stizostedion vit-
reum) eggs held in trays in this zone did not hatch. The hatchability of
northern pike (Esox lucius) eggs was substantially reduced at 25 ng/L at
H2S; at 47 ng/L, mortality was almost complete. Northern pike fry had 96-
hour LC50 values that varied from 17 to 32 ng/L at normal oxygen levels of
6.0 mg/L. The highest concentration of hydrogen sulfide that had no ob-
servable effect on eggs and fry was 14 and 4 (j.g/L, respectively. Eggs, fry,
and juveniles of walleyes and white suckers (Catostomus commersoni) and
safe levels in working on walleyes and fathead minnows (Pimephales pro-
melas) were found to vary from 2.9 ng/L to 12 ng/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
Hg/L. Egg deposition in bluegills was reduced after 46 days in 1.4 ng/L
H2S. White sucker eggs were hatched at 15 (ig/L, but juveniles showed
growth reductions at 1 ng/L. Safe level for fathead minnows were between
2 and 3 M-g/L. Studies showed that safe levels for Gammarus Pseudolimnaeus
and Hexagenia limbata were 2 and 15 ng/L, respectively. Some species typi-
cal 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 |xg/L undissociated H2S would not be hazardous to most fish and other
aquatic wildlife, but concentrations in excess of 2.0 ng/L would constitute
a long-term hazard.
(Quality Criteria for Water, July 1976) PB-263943
See Appendix D for Methodology.
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TAINTING SUBSTANCES
CRITERIA
Aquatic Life 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.
Rationale 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 elim-
inated the commercial fishing industry. Recreational fishing also can be
affected adversely by off-flavor fish. For the majority of sport fishers, con-
suming the catch is part of their recreation; off-flavored catches can divert
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 chemical
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 pollu-
tant. As little as 0.1 fig/L o-chlorophenol can cause tainting of fish flesh. As
little as 5 ^g/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) [Logio [time (min)] -a) - 2°C
where:
Logio = 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.
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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
Table 1.
Table 1.—Regional Limits.
SHORT-TERM
MAXIMUM
MAXIMUM
TRUE DAILY
MEAN*
Sub-tropical regions (south of Cape Canaveral
and Tampa Bay. Fla., and Hawaii)
Cape Hatteras. N.C.. to Cape Canaveral. Fla.
Long island (south shore) to Cape Hatteras,
N.C.
32.2°C (90°F)
32.2°C (90°F)
30.6°C (87°F)
29.4°C (85°F)
29.4°C (85°F)
27.8°C (82°F)
~True daily mean = average or 24 hourly temperature readings.
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.
Introduction 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 recre-
ation 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 cat-
alyst, 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."
Rationale 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-
minute period, temperatures of 10°C or 35°C can be tolerated without harm.
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Temperature also affects the self-purification phenomenon in
waterbodies, 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 solu-
ble 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-
netic 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 pub-
lished 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
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temperature range, the acclimation temperature prior to exposure, and the
time of exposure to the elevated temperature. The upper incipient lethal
temperature or the highest temperature than 50 percent of a sample of or-
ganisms can survive is determined on the organism at the highest
sustainable acclimation temperature. The lowest temperature that 50 per-
cent 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 wa-
ters. However, organisms acclimated to relatively warm water, when
subjected to reduced temperatures that under other conditions of acclima-
tion would not be detrimental, 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 organ-
isms 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;
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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 (°C))
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 Il-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 temper-
ature 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 temper-
ature. Available scientific information includes upper and lower incipient
lethal temperatures, coefficients "a" and "b" for the thermal resistance
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 appears
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 + Vs (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
215
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calculated for the most important life form likely to be present during a
particular month. One caveat in using the maximum weekly mean temper-
ature is that the limit for short-term exposure must not be exceeded.
Example calculations for predicting the summer maximum temperatures
for short-term survival and for extensive exposure for various fish species
are presented in Table 2. These calculations use the above equations and
data from EPA's Environmental Research Laboratory in Duluth.
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
GROWTH'
MAXIMA"
Atlantic salmon
20 (68)
23 (73)
Bigmouth buffalo
—
—
Black crappie
27(81)
—
Bluegill
32 (90)
35 (95)
Brook trout
19 (66)
24 (75)
Carp
—
—
Channel catfish
32 (90)
35 (95)
Coho salmon
18 (64)
24 (75)
Emerald shiner
30 (86)
—
Freshwater drum
—
—
Lake herring (Cisco)
17 (63)c
25 (77)
Largemouth bass
32 (90)
34 (93)
Northern pike
28 (82)
30 (86)
Rainbow trout
19 (66)
24 (75)
Sauger
25 (77)
—
Smalimouth bass
29 (84)
—
Smallmouth buffalo
—
—
Sockcye salmon
18 (64)
22 (72)
Striped bass
—
—
Thrcadfin shad
—
—
White bass
—
—
White crappie
28 (82)
—
While sucker
28 (82)c
—
Yellow perch
29 (84)
—
•Calculated according to (he equation (using optimum temperature for gnmth) maximum weekly average temperature
for growth = optimum temperature + lA (ultimate incipient lethal temperature — optimum temperature).
''Based on temperature (°C) "= l/b |togur