^.-	
arTmental Protection
 ice i
46O7
November, 2OO1
 >ntaminant Candidate List
  iminary Regulatory
 termination Support
   iment for Manganese

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Preliminary Regulatory Determination Support Document for Manganese
November, 2001
                                     Disclaimers

    This document is designed to provide supporting information regarding the regulatory determination
for manganese as part of the Contaminant Candidate List (CCL) evaluation process.  This document is not
a regulation, and it does not substitute for me Safe Drinking Water Act (SDWA) or the Environmental
Protection Agency's (EPA's) regulations. Thus, it cannot impose legally-binding requirements on EPA,
States, or the regulated communily, and may not apply to a particular situation based upon the
circumstances. Mention of trade names or commercial products does not constitute endorsement or
recommendation for use.

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Preliminary Regulatory Determination Support Document for Manganese
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                                 Acknowledgments

    This document was prepared in support of the EPA Office of Ground Water and Drinking Water's
regulatory determination for manganese as part of the Contaminant Candidate List (CCL) evaluation
process. Dan Olson and Karen Wirth served as EPA's team leaders for the CCL regulatory determination
process and James Taft as Standards and Risk Management Division Chief. Tara Cameron and Karen
Wirth served as Work Assignment Managers. The CCL Work Group provided technical guidance
throughout. In particular, Karen Wirth, Dan Olson, and Joyce Donohue provided scientific and editorial
guidance. External expert reviewers and many stakeholders provided valuable advice to improve the
CCL program and this document The Cadmus Group, Inc., served as the primary contractor providing
support for this work. The major contributions of Matt Collins, Emily Brott, and Ashton Koo are
gratefully acknowledged. George Hallberg served as Cadmus' Project Manager.
                                             ill

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                             November, 2001

             Executive Summary
^S^^f7^^^^^^^'^^1-^^-
 ***&!-,, uues exist for manganese (ATSDR. 1 QQ71 A/T  ^N^ 'Contaminant Level fSMCL^ f



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                                       November, 2001
 ^3^5^S^s2S^,-^rWllldll^--*-
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   Preliminary Regulatory Determination Support Document for Manganese


                                     Table of Contents
November, 2001
  Disclaimers	
                                    	  		 i
  Acknowledgments	
                              '		iii
  Executive Summary	
                                 "*'*"""		 v
  Table of Contents	
                               	vii
  List of Tables	
                                     	" "	ix
  1.0 INTRODUCTION  	
         1.1 Purpose and Scope		  1
         1.2 Statutory Framework/Background	  	  *
         1.3 Statutory History of Manganese	  1
         1.4 Regulatory Determination Process	 2
         1.5 Determination Outcome	   	'	 2
                                      	 4
 2.0 CONTAMINANT DEFINITION	
        2.1 Physical and Chemical Properties	'	4
        2.2 Environmental Fate/Behavior	   	  	"		4
                                             '""	 6
 3.0 OCCURRENCE AND EXPOSURE	'[ m..
        3.1 Occurrence	  g
           3.1.1 Use and Environmental Release	"	7
           3.1.2 Environmental Release	:     7
        3.2 Ambient Occurrence	'	  9
           3.2.1 Data Sources andMethods        	  ll
           3.2.2 Results 	'.'.'.'.'.'.	"	'"".	  U
        3.3 Drinking Water Occurrence	.............   	  12
           3.3.1 Analytical Approach	    	"	  14
              3.3.1.1 National Inorganic and Radionuclide Survey		 !?,
              3.3.1.2 Supplemental IOC Data		
              3.3.1.3 Data Management	"	 *4
              3.3.1.4 Occurrence Analysis	  	 ^
           , o o't'1'5,Additional Drinking Water Data from 1996 AWWA Survey	 17
           0.0.2 Kesults 	                             J	 x'
              3.3.2.1 Occurrence in AWWAPWSs	"	 ?7
       3.4  Conclusion ..                            	'"	 1
                        	^	 21
4.0  HEALTH EFFECTS  	
       4.1  Hazard Characterization and Mode of Action Implications."	  ?!
       4.2  Dose-Response Characterization and Implications in Risk Assessment .'	"22
       4.3  Relative Source Contribution                                   	
                                   	  23
                                           vii

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 Preliminary Regulatory Determination Support Document for Manganese
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       4.4 Sensitive Populations	
       4.5 Exposure and Risk Information	  23
       4.6 Conclusion	             	"	  24
                             	-	  24
5.0 TECHNOLOGY ASSESSMENT	
       5.1 Analytical Methods	'.*'.'.'.'.'.'.'.'.	  24
       5.2 Treatment Technology	  25

6.0 SUMMARY AND CONCLUSIONS - DETERMINATION OUTCOME.

References	
Appendix A: Abbreviations and Acronyms
          26

          29

          33
                                       Vlll

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Preliminary Regulatory Determination Support Document for Manganese
                                                                      November, 2001
                                     List of Tables

Table 2-1: Physical and chemical properties	  5

Table 3-1: Imports of manganese and ferromanganese to the U.S. (thousand metric tons, gross weight)
Table 3-2:

Table 3-3:

Table 3-4:
    1998 .
Manganes_e manufacturers and processors by State	  8

Environmental releases (in pounds) for manganese in the United States, 1988-1998	  9

Environmental releases (in pounds) for manganese compounds in the United States, 1988-
                                                                                 10
Table 3-5: Manganese detections and concentrations in streams and ground water	  13

Table 3-6: Manganese detections and concentrations in bed sediments and aquatic biota tissues (all sites)
    	  14

Table 3-7: Manganese occurrence in ground water systems (NIRS survey)	  19

Table 3-8: Occurrence summary of ground and surface water systems, by State, for manganese .....  20

Table 5-1: Analytical Methods for Manganese	  25
                                             IX

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 Preliminary Regulatory Determination Support Document for Manganese
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 1.0 INTRODUCTION

 1.1 Purpose and Scope

    This document presents scientific data and summaries of technical information prepared for, and used
 in, the Environmental Protection Agency's (EPA) regulatory determination for manganese.  Information
 regarding manganese's physical and chemical properties, environmental fate, occurrence and exposure,
 and health effects is included. Analytical methods and treatment technologies are also discussed.
 Furthermore, the regulatory determination process is described to provide the rationale for the decision.

 1.2 Statutory Framework/Background

    The Safe Drinking Water Act (SDWA), as amended in 1996, requires the United States
 Environmental Protection Agency (EPA) to publish a list of contaminants (referred to as the Contaminant
 Candidate List, or CCL) to assist in priority-setting efforts.  The contaminants included on the CCL were
 not subject to any current or proposed National Primary Drinking Water Regulations (NPDWR), were
 known or anticipated to occur in public water systems, and were known or suspected to adversely affect
 public health. These contaminants therefore may require regulation under SDWA. The first Drinking
 Water CCL was published on March 2,1998 (USEPA, 1998b; 63 FR10273), and a new CCL must be
 published every five years thereafter.

    The 1998 CCL contains 60 contaminants, including 50 chemicals or chemical groups, and 10
 microbiological contaminants or microbial groups. The SDWA also requires the Agency to select 5 or
 more contaminants from the current CCL and determine whether or not to regulate these contaminants
 with an NPDWR. Regulatory determinations for at least 5 contaminants must be completed 3'/ years
 after each new CCL.

    Language in SDWA Section 1412(b)(l)(A) specifies that the determination to regulate a contaminant
 must be based on a finding that each of the following criteria are met:

    Statutory Finding i:.. .the contaminant may have adverse effects on the health of persons;

    Statutory Finding ii:    the contaminant is known to occur or there is substantial likelihood that
       the contaminant will occur in public water systems with a frequency and at levels of public
       health concern; and

    Statutory Finding Hi:   in the sole judgement of the Administrator, regulation of such
       contaminant presents a meaningful opportunity for health risk reduction for persons served
       by public water systems.

    The geographic distribution of the contaminant is another factor evaluated to determine whether it
occurs at the national, regional, or local level. This consideration is important because the Agency is
charged with developing national regulations, and it may not be appropriate to develop NPDWRs for
regional or local contamination problems.

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  Preliminary Regulatory Determination Support Document for Manganese
November, 2001
     EPA must determine if regulating this CCL contaminant will present a meaningful opportunity to
  reduce health risk based on contaminant occurrence, exposure, and other risk considerations.  The Office
  of Ground Water and Drinking Water (OGWDW) is charged with gathering and analyzing the
  occurrence, exposure, and risk information necessary to support this regulatory decision. The OGWDW
  must evaluate when and where this contaminant occurs, and what would be the exposure and risk to
  public health. EPA must evaluate the impact of potential regulations as well as determine the appropriate
  measure(s) for protecting public health.                                    .

     For each of the regulatory determinations, EPA must first publish, in the Federal Register me draft
  determinations for public comment EPA will respond to the public comments received, and will then
  finalize regulatory determinations. If the Agency finds that regulations are warranted, the regulations
  must then be formally proposed within twenty-four months, and promulgated by eighteen months later
  EPA has determined that there is sufficient information to support a regulatory determination for
  manganese.

  13 Statutory History of Manganese

     While neither manganese nor any of its compounds are regulated in drinking water, a non-enforceable
 guidance level for aesthetic quality, a Secondary Maximum Contaminant Level (SMCL) of 0.05 mg/L,
 does exist (ATSDR, 1997). Also, manganese and manganese compounds are regulated and/or monitored
 by other federal programs. The discharge of manganese to surface waters is regulated as total  manganese
 under the National Pollution Discharge Elimination System (NPDES) (ATSDR, 1997). Both manganese
 and manganese compounds are listed as a Hazardous Air Pollutants under section 112(b) of the Clean Air
 Act and subject to Best Available Control Technology limits (USEPA, 2000f).  Also, the Comprehensive
 Environmental Response, Compensation,  and Liability Act (CERCLA or "Superfiind") includes
 manganese compounds as hazardous substances, although no reporting thresholds are assigned to this
 broad class (USEPA, 1998a). Manganese is also a Toxic Release Inventory (TRI) chemical The TRI
 was established by the Emergency Planning and Community Right-to-Know Act (EPCRA) which
 requires certain industrial sectors to publicly report the environmental release or transfer of 'chemicals
 included in this inventory.

    Finally, manganese and some of its compounds are listed as air contaminants by the Occupational
 Safety and Health Administration (OSHA). This listing establishes different permissible exposure limits
 (PELs) for various manganese compounds to regulate workplace exposure (ATSDR, 1997).

 1.4 Regulatory Determination Process

    In developing a process for the regulatory determinations, EPA sought input from experts and
 stakeholders. EPA asked the National Research Council (NRC) for assistance in developing a
 scientifically sound approach for deciding whether or not to regulate contaminants on the current and
 future CCLs. The NRC's Committee on Drinking Water Contaminants recommended that EPA- (1)
 gather and analyze health effects, exposure, treatment, and analytical methods data for each contaminant-
 (2) conduct a preliminary risk assessment for each contaminant based on the available data; and (3)  issue
 adecision document for each contaminant describing the outcome of the preliminary risk assessment
 The NRC noted that in using this decision framework, EPA should keep in mind the importance of
involving all interested parties.

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  Preliminary Regulatory Determination Support Document for Mmgan,
tese
                        November, 2001
      One of the formal means by which EPA works withits stakeholders is through the National Drinking
  Water Advisory Council (NDWAC). The NDWAC comprises members of the general public, State and
  local agencies, and private groups concerned with safe drinking water, and advises the EPA Administrator
  on key aspects of the Agency's drinking water program. The NDWAC provided specific
  recommendations to EPA on a protocol to assist the Agency in making regulatory determinations for
  current and future CCL contaminants. Separate but similar protocols were developed for chemical and
  rrucrobial contaminants. These protocols are intended to provide a consistent approach to evaluating
  contaminants for regulatory determination, and to be a tool that will organize information in a manner that
  will communicate the rationale for each determination to stakeholders. The possible outcomes of the
  regulatory determination process are: a decision to regulate, a decision not to regulate, or a decision that
  some other action is needed (e.g., issuance of guidance).

     The NDWAC protocol uses the three statutory requirements of SDWA Section 1412(b)(l)fAiWiu)
  (specified in section 1.2) as the foundation for guiding EPA in making regulatory determination
  decisions. For each statutory requirement, evaluation criteria were developed and are summarized below.

     To address whether a contaminant may have adverse effects on the health of persons (statutory
  requirement (i)), the NDWAC recommended that EPA characterize the health risk and estimate a health
  reference level for evaluating the occurrence data for each contaminant

    Regarding whether a contaminant is known to occur, or whether there is substantial likelihood that
  the contaminant will occur, in public water systems with a frequency, and at levels, of public health
  concern (statutory requirement (ii)), the NDWAC recommended that EPA consider: (1) the actual and
  estimated national percent of public water systems (PWSs) reporting detections above half the health
 reference level; (2) the actual and estimated national percent of PWSs with detections above the health
 reference level; and (3) the geographic distribution of the contaminant

    To address whether regulation of a contaminant presents a meaningful opportunity for health risk
 reduction for persons served by public water systems (statutory requirement (iii)) the NDWAC
 recommended that EPA consider estimating the national population exposed above half the health
 reference level and the national population exposed above the health reference level.

    The approach EPA used to make preliminary regulatory determinations followed the general format
 i^^!^ fceNRC and the NDWAC to satisfy the three SDWA requirements under section
 1412(b)(l)(A)(i)-(ni).  The process was independent of many of the more detailed and comprehensive
 risk management factors that will influence the ultimate regulatory decision making process  Thus a
 decision to regulate is the beginning of the Agency regulatory development process, not the end. '

    Specifically, EPA characterized the human health effects that may result from exposure to a
 contaminant found in drinking water.  Based on this characterization, the Agency estimated a health
 reference level (HRL) for each contaminant.

    For each contaminant EPA estimated the number of PWSs with detections >'/2HRL and >HRL the
population served at these benchmark values, and the geographic distribution, using a large number of
occurrence data (approximately seven million analytical points) that broadly reflect national coverage
Round 1 and1 Round 2 UCM data, evaluated for quality, completeness, bias, and representativeness, were
tne primary data used to develop national occurrence estimates. Use and environmental release

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 regulate a contaminant

 1.5 Determination Outcome
                                     liminaiy
 pre
 rttSS5ESSi^Essfa'L;

 presented in the Federal Register Notice ThS^7   regulatory ^terminations will be
 to reach this preliminary dSrioL        following sections summarize the data used by the Agency

 2.0 CONTAMINANT DEFINITION
minerals
I.oc^
manganese is surpassed in aoirndar.ee only by ton (
                                                      100

2.1 Physical and Chemical Properties

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 Preliminary Regulatory Determination Support Document for Manganese
November, 2001
 2.2 Environmental Fate/Behavior

     The environmental fete and behavior of manganese depends upon the form found in, or released into,
 the environment, and the physical and chemical characteristics of the environment itself. Some
 generalities can be made, however, regarding its behavior in air, water, and soil.

     Naturally occurring manganese and its compounds, as well as anthropogenically released manganese,
 do not evaporate.  However, manganese and its compounds do enter the air as particulate matter through
 soil erosion and industrial emissions. The half-life of airborne particulate matter is on the order of days
 with the smallest particles capable of longer suspension times. Removal of particulate matter is largely
 through dryiall, but some is removed by precipitation (ATSDR, 1997),

     The transport and partitioning of naturally occurring and anthropogenically released manganese in
 water depends upon the solubility of the compound(s) present, which in turn depends upon the Eh
 (oxidation-reduction potential), pH, and the anions available in solution. Ionic manganese is positively
 charged (Mir*). Manganese is also transported in water as suspended sediment (ATSDR, 1997).

     Some of the common manganese compounds are insoluble, but a number of them have low to
 moderate solubility (Table 2-1). Though manganese can exist in water in any of four oxidation states,
 Mn(TI) is the most common and is usually associated with the  carbonate ankm (CQf) to form MnCO3.
 This compound has a relatively low solubility at 65 mg/L (ATSDR, 1997). Manganese may be oxidized
 at high pH or Eh and is also subject to microbial activity (ATSDR, 1997).

    The mobility of soluble manganese in soil depends upon the cation exchange capacity (CEC)  of the
 soil and the amount of soil organic matter. A soil with high CEC and rich in organic matter has an
 abundance of negatively charged particles to attract manganese cations. These reactions form various
 manganese oxides. These oxides are themselves important adsorption sites for other metals (Drever,
 1988). Manganese can adsorb to other oxides through ligand exchange reactions (ATSDR, 1997).

    At low concentrations, manganese cations that react with negatively charged particles in the soil (i.e.,
 organic matter, clay) may not be readily released. Also, the oxidation state of manpanese may be altered'
 by microbial activity (ATSDR, 1997).
3.0 OCCURRENCE AND EXPOSURE

    This section examines the occurrence of manganese in drinking water. While no complete national
database exists of the occurrence of unregulated or regulated contaminants in drinking water from public
water systems collected under SDWA, this report aggregates and analyzes existing federal and State data
that have been screened for quality, completeness, and representativeness. Populations served by public
water systems (PWSs) exposed to manganese are also estimated, and the occurrence data are examined
for special trends. To augment the incomplete national drinking water data and aid in the evaluation of
occurrence, information on the use and environmental release, as well as ambient occurrence of
manganese, is also reviewed.

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Preliminary Regulatory Determination Support Document for Manganese
November, 2001
3.1 Occurrence

    3.1.1 Use and Environmental Release

    In the United States, most manganese ore is smelted to produce feiromanganese which is a
manganese-iron alloy (ATSDR, 1997). The latter is used primarily in the production of steel to improve
stiffness, hardness, and strength. The ore is mined in open pit or shallow underground mines, though
little has been mined in the U.S. since 1978 (ATSDR, 1997; USGS, 2000). Almost all of the manganese
ore used in steel production in the U.S. is imported (see Table 3-1; ATSDR, 1997).  Large quantities of
ferromanganese are imported as well (USGS, 2000). Table 3-2 provides further information, by state, of
the widespread manufacture and processing of manganese.

Table 3-1: Imports of manganese and ferromanganese to the U.S. (thousand metric tons, gross
weight)

manganese ore
ferromanganese
1984
308
-
1988
499
-
1995
394
310
1996
478
374
1997
355
304
1998
332
339
1999 f
535
325
years 1984 and 1988: ATSDR, 1997
years 1995 to 1999: USGS, 2000
t estimated

    Manganese compounds are produced through reactions of various elements and compounds with
either manganese ores or ferromanganese (ATSDR, 1997). Some common manganese compounds
include manganese chloride, manganese sulfate, manganese (Q, HI) oxide, manganese dioxide, and
potassium permanganate (ATSDR, 1997). Usage of these compounds are varied, implying widespread
environmental release.  Significantly, approximately 80% of .the potassium permanganate used in the U.S.
is expended in wastewater and drinking water. Manganese dioxide is used in the production of matches,
dry-cell batteries, fireworks, and as a precursor for other manganese compounds. Manganese chloride is
also used as a precursor for other manganese compounds. A large proportion (60%) of U.S. manganese
sulfate is used as a fertilizer, while the remainder is used in varnish, fungicides, and as a livestock
supplement.  An organic manganese compound, methylcyclopentadienyl manganese tricarbonyl (MMT),
was used as an anti-knock additive in unleaded gasoline before it was banned in 1977. However, a 1995
court decision required EPA to re-register MMT and this process is ongoing (ATSDR, 1997).

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 Preliminary Regulatory Determination Support Document for Manganese
                                                                       November, 2001
 Table 3-2: Manganese manufacturers and processors by State
State*

AR
AZ
CA
CO
CT
FL
GA
in
IA
ID
JL
IN
KS
KY
LA
MA
MD
ME
MI
MN
MO
MS
NC
ND
NE
NH
NJ
NM
NV
NY
OH
OK
OR
PA
PR
RI
SC
SD
TN
TX
UT
VA
WA
Vil
wv

Number of facilities

15
2
39
12
11
11
20
1
32
1
71
63
4
29
5
17
9
7
62
12
27
7
24
1
10
7
16
1
2
37
93
24
13
97
3
1
23
3
24
36 .
11
23
19
67
11

Range of maximum flmmmte QU
site in thousands of pounds6

0-1,000
1-100
0-1,000
0-100
0-1,000
1-1,000
0-1,000
1-10
1-10,000
10-100
0-10,000
0-10,000
0-1,000
0-10,000
0-1,000
0-1,000
0-1,000
1-1000
0-50,000
0-1,000
0-1,000
1-100
0-1,000
10-100
0-50,000
0-100
1,000
10-100
0-100
0-10,000
0-50,000
0-1,000
0-10,000'
0-100,000
0-1,000
10-100
0-1,000
0-1,000
0-10,000
0-10,000
0-10,000
0-1,000
0-1,000
0-1,000
0-10,000
10-100
Activities and uses'
1A3,4A6.73A1J.12,D
U3,4A7,8A10,n,l?,13
1A3,4A6,7,8,9
1A3,4A6,7.8A10,11
23.4A10
1A7.9
1A8A10.13
1A3A7,8A10,12
23.8,13
1A3.4A7.8A12
1,4
1A3,4A6,7,8A10,11,12
13.4A6.7.8A10,! 1,12,13
1A7.8.9
1A3,4A6,7,8A10,12,13
1A3A6.7.8A13
8A10.12
1A3,4,6,8A10,12
7A13
1 A3.4A7.8A10.1 1,12,13
13A8A10,12,13
1A3A7.8A12.13
8,9
1A3,5,8,9,10,12
1A9.11

8,9,13
1A3,4,S,7,8A10,12
9
1A3A7.13

1A3|4A6!7,8A10,11,12
U 4.5 TJ&S) 10 12.13
23!sA10

8A1I "
9
1A7.8A10
1A8A12

1 A3 4 .56 TJSSlo'l 112
' 123.5679') 11 ' '
lA8A10,il,12,13
23,7^A10
1 ,23,5 6 7 8^ 10 12J3
lA3,4A7!8Alo[l3

'Post office Stale abbreviations used
'.Data fe TRIi&e madman amounts on site at each facility
'Activity and Use Codes:
1. Produce
2. Import
3. For oo-site use/processing
4. For sale/distribution
5. As a byproduct
6. As an impurity
7.Asarcactant
8. As a formulation component
9. As a product component
10. For repackaging
11. As a chemical processing aid
12. As a manufacturing aid
13. Ancillary or other uses
source: ATSDR, 1997compilation of 1991 TRIdata

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Preliminary Regulatory Determination Support Document for Manganese
November, 2001
   3.1.2 Environmental Release

   Manganese is listed as a Toxic Release Inventory (TRI) cheniical.  In 1986, the Emergency Planning
and Community Right-to-Know Act (EPCRA) established the TRI of hazardous chemicals. Created
under the Superfund Amendments and Reauthorization Act (SARA) of 1986, EPCRA is also sometimes
known as SARA Title HI. The EPCRA mandates that larger facilities publicly report when TRI
chemicals are released into the environment. This public reporting is required for facilities with more
than  10 full-time employees that annually manufacture or produce mote than 25,000 pounds, or use more
than  10,000 pounds, of a TRI chemical (USEPA, 1996; USEPA, 2000d).

   Under these conditions, facilities are required to report the pounds per year of manganese released
into the environment both on- and off-site. The on-site quantity is subdivided into air emissions, surface
water discharges, underground injections, and releases to land (see Table 3-3).  For manganese, releases
to land constitute most of the on-site releases, with an abrupt decrease occurring in 1989. It is unclear
whether this sharp decrease is real or a function of changes in TRI reporting requirements in the late
1980s and early 1990s (see discussion below).  Land releases have fluctuated modestly since that year
with no trend evident. Air emissions are also an important mode of on-site release. Though the first four
years of record for air emissions are markedly higher, no trend is apparent for the remainder.  Surface
water discharges and underground injection are less significant on-site releases, with underground
injections sharply decreasing in 1994. Low levels of underground injection have continued to the present:
Off-site releases of manganese are considerable. Though in 1990 there is a large drop when compared to
previous years, the late 1990s show a steady increase in pounds released. These TRI data for manganese
were reported from 49 States wim me exception of Alaska and Puerto Rico (USEPA, 2000b).

Table 3-3: Environmental releases (in pounds) for manganese in the United States, 1988-1998
Year
1998
1997
1996
1995
1994
1993
1992
1991
1990
1989
1988
On-Site Releases
Air
Emissions
970,658
751,743
816,733
699,897
818,600
901,827
721,047
1,113,160
1,168,809
2,444,211
1.586.675
Surface Water
Discharges
260,403
146,364
117,571
117,277
89,332
243,999
235,307
143,105
139,358
150,965
321,993
Underground
Injection
3
7
8
17
10
504
304
272
881
556
255
Releases
to Land
9,995,895
9,920,481
10,111,563
8,279,054
8,452,582
7,530,152
6,543,600
9,906,511
9,031,215
7,984,172
20,229.826
Off-Site
Releases
15,967,545
16,209,483
15,191,636
12,753,204
14,076,682
12,150,694
11,997,270
14,590,589
11,364,721
20,559,164
20,087.660
Total On- &
Off-site
Releases
27,194,504
27,028,078
26,237,511
21,849,449
23,437,206
20,827,176
19,497,528
25,753,637
21,704,984
31,139,068
42,226,409
 source: USEPA, 2000b

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  Preliminary Regulatory Determination Support Document for Manganese
                                                                                November, 2001
  aSSr^?           -      eaSS of man8anese compounds (Table 3-4). Releases to land
  again constitute thelargest proportion of on-site releases. With the exception of 1997 and 1998, releases
  to land have genendly decreased over me period of record.  Air emissions are also an important mode of
  release and no trend is evident in the data. Significantly, surface water discharges and uJdergromd
  injections are much more important for me compounds than for elemental manganese, and have been
  generally increasing (dramatically in some years) since the early 1990s.
              ff           :        es '** underground injections have contributed to increases in
         . and off-site releases in recent years. The latter have returned to, or exceeded, the higher lev
            f T- "ld *. *?* *site "** a large component of to^rel^efa
                                              rneseTKIdataformanganesecompoundsW


  5MS98 EnVtr0nmentaI rdeases Cm Punds) for manganese compounds in the United States,
Year
1998
1997
1996
1995
1994
1993
1992
1991
1990
1989
	 1988
source: USEi

Air
Emissions
1,566,352
1,549,505
1,828,684
2928644
3,060,424
2,324,442
2,079,044
1,531,832
2,276,084
1,847,528
1.801.463
*A.2000b
On-Site Releases
Surface Water
Discharges
4,471,582
4,202,876
2,119,241
1 (ffi 1R4.
857,825
685,737
733,728
709,557
' 721,787
907,866
681.469
Underground
Injection
7,755,610
14,412,830
15,630
3,590
5,930
8,740
22,569
15,327
2,842
1,005,518
6,816.070
Releases
to Land
52,820,578
50,141,026
40,334,426
41,832,058
38,228,464
47,763,821
63,490,137
66,559,047
83,331,787
85,191,013
84.227.842
f\ff CJ*.
VlM-MK!
Release:;
45,269,882
47,233,186
33,543,677
25,994,951
25,840,954
22,780,860
17,297,544
27,250,630
35,789,554
33,004,908
20.670.921
Total On- &
Off-site
Releases
111 884 004
117539423
77,841,658
72,386,427
67 993 597
73 561 6OO
83,623,022
96,066,393
122 122 054
121,956,833
114.197.765
    Although the TRT date can be useful in giving a general idea of release trends, it is far from
ftfflS^f     ^ ficanttotetions. For example, only industries that meet TRI criteria (at least 10
                8    "" "d POCeSSing f quantities exceeding 25'000 lbs/vr, or use Smore
                                      eases- These rePorting criteria do not amount for releases
                                                                              m 1988  1990
                                                                              om
                                 to 50,000 Ibs/yr in 1989 to its current 25,000 Ibs/yr in 1990)

                                 * FiDally' ^  ^ is meant to refl^ releass d should not
                            sure to a chemical (USEPA, 2000c; USEPA, 2000a).

    Li summary, manganese and many of its compounds are naturally occurring and found at low levels
mTlr' ^'T *4.JWtaB^ "anganese compounds are produced^ the iSX
manganeseoreandaremwidespreaduse. Most ferromanganese is used in steel production whSot
manganese compounds are used in a variety of applications, from fertilizers and SSSlSSSi to
water treatment Recent statistics regarding import for consumption indicate production anKe at

                                            10

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Preliminary Regulatory Determination Support Document for Manganese
November, 2001
robust (Table 3-1). Manganese and its compounds are also TRI chemicals (Tables 3-3 and 3-4).
Industrial releases have occurred since 1988 in all 50 States. Off-site releases constitute a considerable
amount of totalreleases. Releases to land arssihe most significant pn-site releases.

3.2 Ambient Occurrence

    To understand the presence of a chemical in the environment, an examination of ambient occurrence
is useful. In a drinking water context, ambient water is source water existing in surface waters and
aquifers before treatment. The most comprehensive aridnationally consistent data describing ambient
water quality in the United States are being produced through the United States Geological Survey's
(USGS) National Water Quality Assessment (NAWQA) program. (NAWQA, however, is a relatively
young program and complete national data are not yet available from their entire array of sites across the
nation.)   ';"'"      .      ':''.''..   "         .      .---.    -   .,   ,,  '..  .-      .          .....

    3^2.1 Data Sources and Methods

    The USGS instituted the NAWQA program in 1991 to examine water quality status and trends in the
United States. NAWQA is designed and implemented in such a manner as to allow consistency and
comparison between representative study basins located around the country, facilitating interpretation of
natural and anthropogenic factors affecting water quality (Leahy and Thompson, 1994).

    The NAWQA program consists of 59 significant watersheds and aquifers referred to as "study units."
The study units represenitapproximately two thirds of the overall water usage in the United States and a
similar proportion of the population served by public water systems. Approximately one half of the
nation's land area is represented (Leahy and Thompson,; 1994).

    To facilitate management and make the program cost-effective, approximately one third of the study
units at a time engage in intensive assessment for a period of 3 to 5 years. This is followed by a period of
less intensive research and monitoring that lasts between 5 and 7 years.  In this way, all 59 study units
rotate mrough intensive assessment over a ten-year period (Leahy and Thompson, 1994). The first round
of intensive monitoring (1991-1996) targeted 20 study units, and the second round monitored another 16,
beginning in 1994.

    Manganese is an analyte for both surface and ground water NAWQA studies, with a Minimum
Reporting Level (MRL) of 0.001 mg/L. Manganese occurrence in bed sediments and aquatic biota tissue
is also assessed, with MRLs of 4 mg/kg and 0.1 mg/fcg, respectively.

    Manganese data from the first two rounds of intensive NAWQA monitoring have undergone USGS
quality assurance checks and are available to the public through their NAWQA Data Warehouse (USGS,
2001). EPA has anaryzed*these data after further data quality review, and occurrence results are presented
below. The descriptive statistics generated from the manganese NAWQA data broadly characterize the
 frequency of manganese detections by sample and by site. Furthermore, detection frequencies above a
Health Reference Level (HRL) of 0.30 mg^L are also presented for all samples, and by site. The HRL is a
preliminary health effect level used for  this analysis (see Section 3.3.1.4 for further discussion of the HRL
 and its development).  The median and  99th percentile concentrations are included as well, to characterize
 the spread of manganese concentration  values in ambient waters sampled by the NAWQA program.
                                              11

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Preliminary Regulatory Determination Support Document for Manganese
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    3.2.2 Results

    Typical of many inorganic contaminants, manganese occurrence in ambient surface and ground
waters is high (Table 3-5). This is not surprising, considering that manganese constitutes approximately
0.1% of the earth's crust (of the heavy metals, it is surpassed in abundance only by iron), and the element
and its compounds are used in many products.  Significantly, manganese compounds are used in
.wastewater and drinking water treatment

    Detection frequencies are consistently greater for surface water than for ground water, possibly
because surface waters are more sensitive to anthropogenic releases. Median concentrations are also
generally higher for surface water (median concentration for all sites is 0.016 mg/L hi surface water and
0.005 mg/L in ground water). However, manganese detection frequencies greater than the HRL ;are
consistently higher in ground water, and 99* percentile ground water concentrations are as much as eight
times larger than corresponding 99th percentile surface water concentrations. Locally high concentrations
in ground water, higher than any seen in surface water, are not surprising given the possibility of long
contact times between ground water and rocks enriched in manganese. Contact times between surface
waters and naturally occurring manganese are orders of magnitude shorter, hence concentrations are
lower. Furthermore, surface waters subject to large anthropogenic inputs of manganese are more easily
diluted by waters integrated from other parts of the watershed, where manganese concentrations may be
lower.

    Table 3-5 illustrates that low-level manganese occurrence is ubiquitous. Surface water detection
frequencies by site are greater than 95% for all land use categories. Median concentrations and HRL
exceedances (by site) are greater in urban and agricultural basins compared to basins characterized as
mixed land use or forest/rangeland. This distribution of manganese occurrence is probably influenced by
the wide use of manganese compounds in both industry and agriculture. Mixed land use basins are
generally larger than either urban or agricultural basins, and the lower occurrence in these basins may
reflect some dilution of the contaminant The 99th percentile concentrations for surface water range from
0.4 mg/L-0.8 mg/L. The frequency of detections exceeding the MRL and HRL by site for all sites are
approximately 96.9% and 10.2%, respectively. These figures indicate that although manganese is nearly
ubiquitous in surface water, detections at levels of public health concern are relatively low.

    For ground water, detections by site are higher in urban and forest/rangeland areas than in mixed or
agricultural lands. Over 80% of urban and forest/rangeland sites  reported detections, while approximately
63-64% of mixed and agricultural land use sites detected manganese. The finding that ground water
manganese occurrence is higher in forest/rangeland areas than in  either mixed or agricultural sites may
result from natural variation in manganese occurrence in soil and rock. Urban areas have the highest
median and 99th percentile concentrations (0.015 mg/L and 5.6 mg/L, respectively), as well as the highest
detection frequencies (by site: 85.3%) and HRL exceedances (both by sample [17.2%] and by site [21%]).
These results suggest that urban releases of manganese and manganese compounds can leach to ground
water.

    Detection frequencies and HRL exceedances by site for all ground water sites are approximately
70.1% and 13.8%, respectively.  Again, these figures suggest that while manganese occurrence in ground
water is high, detections at levels of public health concern are modest.
                                              12

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Preliminary Regulatory Determination Support Document for Manganese
                                  November, 2001
    Manganese was detected at 100% of NAWQA stream bed sediment sampling sites. The median and
99th percentile concentrations in bed sediments are 1.1 mg/kg (dry weight) and 9.4 mg/kg (dry weight),
respectively.  The occurrence of manganese in stream sediments is pertinent to drinking water concerns
because, though many manganese compounds are either insoluble or have low solubility and are
transported in water as suspended sediment, some desorption of the compound from sediments into water
will occur through equilibrium reactions, although at very lowrates.

    In aquatic biota tissue, detections are also 100% for all samples and sites (Table 3-6). However,
concentration percetttiles for tissues are substantially lower than for bed sediments:  the median for biotic
tissue is 0.01  mg/kg (dry weight) and the 99th percentile is 2.9 mg/kg (dry weight).  Significant
manganese concentrations in aquatic biota tissues would imply a potential for bioaccumulation.  Although
manganese was detected in aquatic biota tissues at 100% of samples and sites, low concentration
percentiles suggest that the element does not bioaccumulate appreciably.
Table 3-5: Manganese detections and concentrations in streams and ground water
                        Detection frequency
                       '>.     >MRL*
Detection frequency
      >HRL*
  Concentrations
(all samples; mg/L)

surface water
urban
mixed
agricultural
forest/rangeland
all sites
ground water
urban
mixed
agricultural
forest/rangeland
all sites
% samples

99.1 %
92.4%
96.3 %
90.9%
94.0%

74.7%
56.9%
61.4%
75.3 %
, 64.1%
% sites

99.6 %
98.5 %
"97.2%
96.4%
96.9%

85.3 %
62,9%
64.0 %
81.3 %
70.1 %
% samples

4.6 %
1.3%
3.7%
5.0 %
3.0 %

17.2 %
8.9%
11.9%
10.9 %
12.8%
% sites

13.0 %
6.4%
12.3 %
6.6%
10.2%

21.0%
9.0%
12.8%
13.8%
13.8 %
median

0.036
0.012
0.019
0.011
0.016

0.015
0.002
0.004
0.012
0.005
22*
percentile

0.7
0.4
0.7
0.8
0.7

5.6
1.3
1.6
2.9
2.9
                                                                                      TheHRLisa
 preliminary health Affect level used for this investigation.
                                               13

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Preliminary Regulatory Determination Support Document for Manganese
                           November, 2001
Table 3-6: Manganese detections and concentrations in bed sediments and aquatic biota tissues (all
sites)
                             Detection frequency
                                  >MRL*
       Concentrations
(all samples; rag/kg dry weight)

sediments,
aquatic biota tissues
% samples
100%
100%
% sites
100 %
100%
median
1-1
0.01
99"* percentile
9.4
2.9
* The Minimum Reporting Levels (MKLs)for manganese in sediments and biota tissues are 4 fig/g and 0.1 pg/g, respectively.
33 Drinking Water Occurrence

    33.1 Analytical Approach

    33.1.1 National Inorganic and Radionuclide Survey

    In the mid-1980s, EPA designed and conducted the National Inorganic and Radionuclide Survey
(NIRS) to collect national occurrence data on a select set of radionuclides and inorganic chemicals being
considered for National Primary Drinking Water Regulations. The NIRS database includes 36 inorganic
compounds (IOC) (including 10 regulated lOCs), 2 regulated radionuclides, and 4 unregulated
radionuclides. Manganese was one of the 36 lOCs monitored.

    The NIRS provides contaminant occurrence data from 989 community PWSs served by ground water.
The NIRS does not include surface water systems. The selection of this group of PWSs was designed so
that the contaminant occurrence results are statistically representative of national occurrence. Most of the
NIRS data are from smaller systems (based on population served by the PWS) and each of these
statistically randomly selected PWSs was sampled a single time between 1984 and 1986.

    The MRS data were collected from PWSs in 49 States (data were not available for Hawaii). In
addition to being statistically representative of national occurrence, NIRS data are designed to be divisible
into strata, based on system size (population served by the PWS).  Uniform detection limits were
employed, thus avoiding computational (statistical) problems that sometimes result from multiple
laboratory analytical detection limits. Therefore, the NIRS data can be used directly for national
contaminant occurrence analyses with very few, if any, data quality, completeness, or representativeness
issues.

    33.1.2 Supplemental IOC Data

    One limitation of the NIRS study is a lack of occurrence data for surface water systems. To provide
perspective on the occurrence of manganese in surface water PWSs relative to ground water PWSs,
SDWA compliance monitoring data that were available to EPA were reviewed from States with
occurrence data for both ground and surface water.
                                              14

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Preliminary Regulatory Determination Support Document for Manganese
                                                                               November, 2001
    The State ground water and surface water PWS occurrence data for manganese used in this analysis
were submitted by States for an independent review of tile occurrence of regulated contaminants in PWSs
atvarioustimesfordifferentprogramsCUSEPA, 1999).  to the USEPA (1999) review occurrence data
from a total of 14 States were noted. However, because several States contained data that were ^
incomplete or unusable for various reasons, only 12 of the 14 States were used for a general overview
analysis  From these 12 States, 8 were selected for use in a national analysis because they provided the
best data quality and completeness and a balanced national cross-section of occurrence data.  These eight
were Alabama, California, Illinois, Michigan, Montana, New Jersey, New Mexico, and Oregon.

    Only 1he Alabama, California, Illinois, New Jersey, and Oregon State data sets contained occurrence
data for manganese. The data represent more than 37,000 analytical results from about 4,000 PWSs,
primarily collected from 1993 to 1997, though some earlier data are also included. The number of sample
results and PWSs vary by State.

    33.13  Data Management

    The data used in the State data analyses were limited to only those data with confirmed water source
 and sampling type information. Only standard SDWA compliance samples were used; "special" samples,
 or "investigation" samples (investigating.a contaminant problem that would bias results), or samples of
 unknown type were not used in the analyses. Various quality control and review checks were made of the
 results  including follow-up questions to the States providing the data. Many of the most intractable data
 quality problems encountered occurred with older data. These problematic data were, in some cases,
 simply eliminated from the analysis. For example, when the number of problematic data were ^
 insignificant relative to the total number of observations, they were dropped from the analysis (for further
 details see USEPA, 1999).

    3 J.I .4  Occurrence Analysis

    The summary descriptive statistics presented  in Table 3-7 for manganese are derived from analysis of
 the NIRS data  Included are the total number of samples, the percent samples with detections, the 99
 percentile concentration of all samples, the 99th percentile concentration of samples with detections, and
 the median concentration of samples with detections. The percentages of PWSs and populationserved
 indicate the proportion of PWSs and PWS population served for which analytical results showed a
 detections) of the contaminant (simple detection, > MRL) at any time during the monitoring period; or a
 detections) greater than half the Health Reference Level (HRL); or a detections) greater than the HRL.
 The HRL used for this analysis is 0.30 mg/L.

     The HRLs were derived for contaminants not considered to be "linear" carcinogens by the oral route
 of exposure. EPA derived the HRL using a Reference Dose (RfD) approach as follows: HRL = (RfD x 70
 kg)/2LxRSC, where:

         RfD = an estimate of a daily oral exposure to the human population (including sensitive
         subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime.
         It can be derived from a No Observed Adverse Effect Level, Lowest Observed Adverse Effect
         Level, or benchmark dose, with uncertainty factors generally applied to reflect limitations of the
         data used;
                                               15

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Preliminary Regulatory Determination Support Document for Manganese
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       70 kg=The assumed body weight of an adult;

       2L = The assumed daily water consumption of an adult;

       RSC = The relative source contribution, or the level of exposure believed to result from drinking
       water when compared to other sources (e.g., air), and is assumed to be 20% unless noted
       otherwise.

    EPA used only the best available peer reviewed data and analyses in evaluating adverse health
effects. Health effects information is available for manganese in the Integrated Risk Information System
(IRIS). IRIS is an electronic EPA database containing reviewed information (both inside and outside of
the Agency) on human health effects that may result from exposure to various chemicals in the
environment These chemical files contain descriptive and quantitative information on RfDs for chronic
noncarcinogenic health effects and hazard identification; slope factors; and unit risks for carcinogenic
effects.

    In Table 3-7, national occurrence is estimated by extrapolating the summary statistics for manganese
to national numbers for systems, and population served by systems, from the Water Industry Baseline
Handbook, Second Edition (USEPA, 2000e). From the handbook, the total number of ground water
community water systems (CWSs) plus ground water non-transient, non-community water systems
(NTNCWSs) is 59,440, and the total population served by ground water CWSs plus ground water
NTNCWSs is 85,681,696 persons (see Table 3-7).  To arrive at the national occurrence estimate for the ,
HRL, the national estimate for ground water PWSs (or population served by ground water PWSs) is
simply multiplied by the percentage for the given summary statistic [i.e., the national estimate for the total
number of ground water PWSs with detections at the HRL of 0.30 mg/L (40,388) is me product of the
percentage of ground water PWSs with detections (68%) and the national estimate for the total number of
ground water PWSs (59,440)].

    The nationally extrapolated occurrence estimates for manganese are not presented in the Federal
Register Notice. While the MRS data were collected in a statistically appropriate fashion suitable for
extrapolation, the data available for many CCL regulatory determination priority contaminants were not a
strict statistical sample.  National extrapolations of these data can be problematic. Also, the NIRS data
only represent ground water PWSs.  Thus, national extrapolations from NIRS data do not represent
national occurrence for all PWSs. Therefore, to maintain consistency across all CCL regulatory
determination priority contaminants, a straight-forward presentation, and data integrity, only the actual
occurrence results for all CCL regulatory determination priorities are presented in the Federal Register
Notice for stakeholder review. The nationally extrapolated occurrence values for manganese are
presented here, however, to provide additional perspective.

    In Table 3-8, occurrence data on manganese directly submitted by the States of Alabama, California,
Illinois, New Jersey, and Oregon for A Review of Contaminant Occurrence in Public Water Systems
(USEPA, 1999) was used to augment the NIRS study which lacked surface water data. Included in the
table are the same summary statistics as in Table 4-1, with additional information describing the relative
distribution  of manganese occurrence between ground water and surface water PWSs in the 5 States.

    The State data analysis was focused on occurrence at the system level because a PWS with a known
contaminant problem usually has to sample more frequently than a PWS that has never detected the
                                              16

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Preliminary Regulatory Determination Support Document for Manganese
November, 2001
contaminant The results of a simple computation of the percentage of samples with detections (or other
statistics) can be skewed by the more frequent sampling results reported by the contaminated site. The
system level of analysis is conservative. For example, a system need only have a single sample with an
analytical result greater than the MRL, i.e., a detection, to be counted as a system with a result "greater
than the MRL."

    When computing basic occurrence statistics, such as the number or percent of samples or systems
with detections of a given contaminant, me value (or concentration) of the MRL can have important
consequences. For example, the lower the reporting limit, the greater the number of detections (Ryker
and Williamson, 1999). As a simplifying assumption, a value of half the MRL is oftenused as an
estimate of the concentration of a contaminant in samples/systems whose results are less than the MRL.
However, for these occurrence data this is not straightforward. This is in part related to State data
management differences as well as real differences in analytical methods, laboratories, and other factors.

    The situation can cause confusion when examining descriptive statistics for occurrence.  Because a
simple meaningful summary statistic is not available to describe the various reported MRLs, and to avoid
confusion, MRLs are not reported in the summary table (Table 3-8).

    3.3.1.5 Additional Drinking Water Data from 1996 AWWA Survey

    To augment the SBWA drinking water data analysis described above, results from a 1996 American
Water Works Association (AWWA) survey are reviewed.  The survey, called WaterStats, is a cooperative
project of AWWA and AWWA Research Foundation. The WaterStats survey database stores results
from the 1996 WaterStats survey of water utilities in the United States and Canada in terms of facilities,
scale of operation, and major inputs and outputs. A total of 794 AWWA member utilities responded to
the survey with ground water and/or surface water information. However, the actual number of
respondents for each data category varies because not all participants in the survey responded to every
question.

     33.2 Results

     The NIRS data in Table 3-7 show that approximately 68% of ground water PWSs (an estimate of
 approximately 40,000 systems nationally) had detections of manganese, affecting about 55% of the
 ground water PWS population served (approximately 47.5 million people nationally).  At an HRL of 0.30
 mg/L, approximately 6.1% of the NIRS PWSs had detections greater than half the HRL (about 3,600
 ground water PWSs nationally), affecting approximately 4.6% of the population served (estimated at 3.9
 million people nationally). The percentage of MRS PWSs with detections greater than the HRL of 0.30
 mg/L was approximately 3.2% (about 1,900 ground water PWSs nationally), affecting 2.6% of the
 population served (estimated at approximately 2.3 million people nationally) (Table 3-7).

     Drinking water data for manganese from the supplemental individual States vary among States (Table
 3-8). Manganese has not been required for monitoring under the SDWA, though these States had
 obviously conducted some monitoring. The number of systems with manganese data for Illinois and
 Oregon is far less than the number of PWSs in these States. Hence, it is not clear how representative
 these data are. Alabama, California, and New Jersey have substantial amounts of data and PWSs
 represented.  Because the NIRS data only represent manganese occurrence in ground water PWSs, the
 supplemental State  data sets provide some perspective on surface water PWS occurrence. For example,
                                              17

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Preliminary Regulatory Determination Support Document for Manganese
November, 2001
the median concentration of detections for the States ranged from 0.02 mg/L to 0.15 mg/L, higher than
the NIRS data (0.01 mg/L). For detections by PWSs, 3 of the 5 States (California, Illinois, and Oregon)
had higher ground water PWS detections.

    For simple detections, the supplemental State data show a range from 30% to 56% of ground water
PWSs (Table 3-8). These figures are lower than the NIRS ground water PWS results: 68% greater than
the MRL (Table 3-7). The supplemental State data show considerably greater percentages of simple
detections for surface water PWSs, with higher variability as well: 12% - 97% greater than the MRL.
Comparisons made between data for simple detections need to be viewed with caution because of
differences in MRLs between the State data sets and the NIRS study, and among the States themselves
(see Section 3.3.1.4).

    The supplemental State data sets indicate ground water PWS detections greater than the HRL of 0.30
mg/L between 0.6% and 11% (Table 3-8). Again, this range brackets the NIRS national average of PWS
above the HRL of 0.30 mg/L (3.2%) (Table 3-8). Notably, surface water PWSs showed fewer
exceedances of the HRL than ground water PWSs at this higher concentration; ranging from 0% to 3.1%.
    Reviewing manganese occurrence by PWS population served shows that from 0.1% - 43% of the
States' ground water PWS populations were served by systems with detections greater than the HRL of
0.30 mg/L (Table 3-8). Comparatively, 2.6% of the NIRS ground water PWS population served
experienced detections greater than the HRL of 0.30 mg/L (Table 3-7). Populations served by surface
water PWSs with detections greater than the HRL of 0.30 mg/L ranged from 0% - 14.5% among the five
supplemental States. Population figures for the supplemental States are incomplete and are only reported
for those systems in the database that have reported their population data.  For manganese, approximately
80% of the PWSs reporting occurrence data for these 5 States also reported population data.

    3.3.2.1 Occurrence in AWWA PWSs

    The AWWA sponsored 1996 WaterStats Survey showed manganese occurrence above levels of
health concern to be generally similar to those reported in the NIRS data and the supplemental State data.
In finished ground water samples, approximately 3% of survey respondents (serving close to 1.6 million
people) had maximum detections of manganese greater than the HRL of 0.30 mg/L. The 99th percentile .
concentration and the median concentration were 0.80 mg/L and 0.021 mg/L, respectively. For finished
surface water samples, approximately 1.5% of survey respondents (serving about 1.7 million people)
reported maximum detections greater than the HRL of 0.30 mg/L. The 99th perceritile concentration and
the median concentration in finished surface water samples were 0.64 mg/L and 0.013 mg/L, respectively.

    Approximately 11% of the participating ground water PWSs (serving about 5.1 million people) had
maximum detections of manganese in raw water greater than the HRL of 0.30 mg/L. The 99th percentile
of concentration and the median concentration were 9.0 mg/L and 0.09 mg/L, respectively. Surface water
PWSs showed comparable results, with approximately 12.8% of survey respondents (serving about to
10.5 million people) having maximum detections of manganese in raw water greater than the HRL of 0.30
mg/L.  The 99* percentile of concentration and the median concentration in raw surface waters were 3.08
mg/L and 0.092 mg/L, respectively.
                                             18

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Preliminary Regulatory Determination Support Document for Manganese
November, 2001
Table 3-7: Manganese occurrence in ground water systems (NIRS survey)
:

Frequency Factors
Total Number of Samples/Systems
99th Percentile Concentration (all samples)
vlinimum Reporting Level (MRL)
99th Percentile Concentration of Detections
Median Concentration of Detections
Total Population

Occurrence by Sample/System
% Ground Water PWSs with detections (> MRL)
Range of Sampled States
% Ground Water PWSs > 1/2 Health Reference Level (HRL)
Range of Sampled States
% Ground Water PWSs > HRL
Range of Sampled States
Occurrence by Population Served
% Ground Water PWS Population Served with detections
Range of Sampled States
% Ground Water PWS Population Served > 1/2 HRL
Range of Sampled States
% Ground Water PWS Population Served > HRL
Range of Sampled States
Health Reference
Level = 030 mg/L

989
0.63 mg/L
0.001 mg/L
0.72 mg/L
0.01 mg/L
1,482,133


67.9%
8.3-100%
6.1%
0-31.6%
3.2%
0-21.0%

55.4%
0.3 - 100%
4.6%
0 - 89.2%
2.6%
0 - 89.2%
National System &
Population Numbers1

59,440
 -
-


85,681,696
National Extrapolation
HRL = 030
40,388
N/A
3,606
N/A
1,923
N/A

47,502,000
N/A
3,940,000
N/A
2,256,000
N/A
  Total PWS and population numbers are from EPA March 2000 Water Industry Baseline Handbook.
                                                 19

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Preliminary Regulatory Determination Support Document for Manganese
November, 2001
Table 3-8: Occurrence summary of ground and surface water systems, by State, for manganese
Freqnea cy Factors
Total Number of Samples
Number of Ground Water Samples
Number of Surface Water Samples
Percent of Samples with Detections
Percent of Ground Water Samples with Detections
Percent of Surface Water Samples with Detections
99* Pcrcentile Concentration (all samples)
Minimum Reporting Level (MRL)
99* Pcrcentile Concentration of Detections
Median Concentration of Detections
Total Number of PWSs
Number of Ground Water PWSs
Number of Surface Water PWSs
Total Population Served
Ground Water Population
Surface Water Population
Occurrence by System
% PWSs with detections (> MRL)
Ground Water PWSs with detections
Surface Water PWSs with detections
Health Reference Level (HRL) = 0.03 mg/L
/ PWSs > 1/2 HRL
Ground Water PWSs > 1/2 HRL
Surface Water PWSs > 1/2 HRL
% PWSs > HRL *
Ground Water PWSs > HRL
Suffice Water PWSs > HRL
Occurrence by Population Served
'/ PWS Population Served with detections
Ground Water PWS Population with detections
Surface Water PWS Population with detections
Health Reference Level (HRL) = 0.03 rog/L
% PWS Population Served > 1/2 HRL
Ground Water PWS Population > 1/2 HRL
Surface Water PWS Population> 1/2 HRL
% PWS Population Served > HRL
Ground Water PWS Population > HRL
Surface Water PWS Population > HRL
Alabama
1,343
934
409
30.2%
28.1%
35.0%
0.13 mg/L
Variable1
0.56 mg/L
0.02 mg/L
434
365
69
3,662,222
1,820,214
1,837,743

46.5%
41.6%
72.5%

1.8%
1.4%
4.4%
0.9%
0.6%
2.9%

71.9%
50.9%
73.4%

5.9%
0.8%
0.7%
2.4%
0.1%
0.6%
California
31,998
29,923
2,075
16.5%
17.5%
1.9%
0.71 mg/L
Variable1
1^2 mg/L
0.15 mg/L
2,516
2,293
223
45,388,246
27,840,774
30,675,992

28.2%
29.8%
11.7%

17.2%
183%
3.6%
10.1%
10.9%
1.8%

49.3%
66.2%
10.5%

34.8%
52.6%
4.4%
27.2%
42.8%
4.2%
Illinois
344
275
69
44.2%
50.2%
203%
0.96 mg/L
Variable1
57rag/L
0.04 mg/L
227
160
67
1,995,394
724,635
1,270,179

41.4%
50.6%
19.4%

9.3%
11.9%
3.0%
4.4%
5.0%
3.0%

36.5%
663%
19.5%

16.5%
29.1%
9.4%
14.7%
24.2%
9.4%
New Jersey
3,196
2,795 ;
. 401
39.7%
40.6%
33.7%
0.42 mg/L
Variable1
0.89mg/L
0.02 mg/L
1,179
M47
32
7,472,565
2386396
3,687,076

53.5%
. 523%
96.9%

5.8%
5.7%
9.4%
2.5%
2.5%
3.1%

85.7%
70.4%
100.0%

153%
10.4%
233%
9.1%
4.9%
143%
Oregon
172
90
82
39.5%
61.1%
15.9%
1.6 mg/L
Variable1
6.7 mg/L
0.05 mg/L
84
54
30
1,306,283
301,440
1,117,782

46.4%
55.6%
30.0%

13.1%
20.4%
0.0%
6.0%
9.3%
0.0%

58,0%
41.8%
56.8%

4.6%
19.9%
0.0%
3.2%
14.0%
0.0%
1 See Section 3.3.1.4'for details
                                              20

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Preliminary Regulatory Determination Support Document for Manganese
November, 2001
3.4 Conclusion

    Manganese and its compounds are TRI chemicals. Industrial releases have been reported since 1988
in all 50 States. Off-site releases constitute a considerable amount of total releases, with releases to land
the most significant on-site releases.

    Low-level manganese occurrence in ambient waters and bed sediments monitored by the USGS
NAWQA program is ubiquitous, with detections approaching 100% of surface water sites and greater
than 62% of ground water sites. Stream bed sediments and aquatic biota tissues show detections of 100%
by sample and by site. Urban basins generally have more surface and ground water manganese detections
greater than the HRL than basins in other land use categories do, and higher median and 99th percentile
concentrations. Although manganese detection frequencies are high in ambient waters, stream bed
sediments, and aquatic biota tissue, manganese occurrence at levels of public health concern is low.

    Manganese has been detected in ground water PWS samples collected through the NIRS study.
Occurrence estimates are relatively high, with approximately 68% of all samples showing detections
affecting about 55% of the national population served. The 99th percentile concentration of all samples is
0.63 mg/L. Exceedances of the HRL at 0.30 mg/L affect approximately 2.3 million people nationally.

    Additional SDWA compliance data from the States of Alabama, California, Illinois, New Jersey, and
Oregon, including both ground water and surface water PWSs, were examined through independent
analyses and also show substantial levels of manganese occurrence. These data provide perspective on
the NIRS estimates that only include data for ground water systems. The supplemental State data show
ground water systems reported higher manganese detections in 3 of the 5 States (California, Illinois, and
Oregon). If national  data for surface water systems were available, the occurrence and exposure estimates
would be substantially greater than from MRS alone.          *
4.0  HEALTH EFFECTS

   A description of the health effects and dose-response information associated with exposure to
manganese is summarized below. For additional detail, please refer to the Health Effects Support
Document for Manganese (USEPA, 2001b).

4.1 Hazard Characterization and Mode of Action Implications

   The primary route of exposure to toxic levels of manganese is through the inhalation of manganese
dust Oral exposure to levels of lexicological concern is less common. The major adverse health effect of
manganese exposure is neurotoxicity, which is characterized at high doses by ataxia (i.e., coordination
impairment), increased anxiety, dementia, a "mask-like" face, involuntary movements, or a syndrome
similar to Parkinson's disease. While the precise mechanisms of manganese neurotoxicity are not known,
the observed effects of manganese on the globus pallidus region of the brain suggest that a likely
mechanism involves impairment of the neurotransmitter dopamine, which is involved in coordination of
movement.

   While manganese is potentially harmful at high concentration levels, it is also an essential nutrient in
developing infants. For this reason, the adverse effects from manganese deficiency may, at times, be of
                                             21

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 Preliminary Regulatory Determination Support Documentfor Manganese
November, 2001
 greater concern than potential toxicity from over-exposure. An added complication is the fact that many
 inhibitors of manganese absorption, such as phytates and plant fiber, are commonly found in infant diets,
 thus lowering the actual absorption of ingested manganese. Absorption of the mineral from manganese-
 rich foods may also be inhibited by the presence of co-occurring plant proteins that bind manganese and
 decrease its bioavailability.  For example, although the manganese content in a soy-based formula is
 higher than the manganese content in human milk, the actual absorption of manganese from the formula
 may not be substantially greater, since soy milk is high in phytate and vegetable protein. Human and cow
 milk contain different proteins that also bind manganese, but in some cases, the presence of these proteins
 actually enhances manganese transport across the gut wall, increasing absorption.

    Other instances in which high dietary levels of manganese may not necessarily correspond to high
 dose levels include vegetarian diets and tea drinkers. Many vegetables contain high manganese levels but
 have high fiber and phytate levels. Likewise, tea contains high manganese levels, but the accompaniment
 of tannin, another inhibitor of manganese absorption, decreases the absorption of manganese.

    Several studies have explored the intake level of manganese at which it may be considered safe in
 humans. Although the Estimated Safe and Adequate Daily Dietary Intake (ESADDI) for manganese has
 been established at 2-5 mg/day for adults (NRC, 1989), Davis  and Greger (1992) have found that a daily
 intake of 15 mg/day for 90 days results in no adverse effects in women; the only effect seen was an
 increase in superoxide dismutase activity. In 2001, the Institute of Medicine (IOM) undertook a review
 of Dietary Reference Intakes for a number of substances. An adequate intake level for manganese was set
 at 2.3 mg/day for men and 1.8 mg/day for women (IOM, 2001). The IOM report also sets a tolerable
 upper intake level of 11 mg/day for adults, based on a review by Greger (1999). It suggested that people
 eating Western type and vegetarian diets may have intakes as high as 10.9 mg/day.

 4.2 Dose-Response Characterization and Implications in Risk Assessment

    The dose-response relationship for neurological effects of manganese by ingestion is not well-
 characterized in annuals or humans. Epidemiological data for humans indicate that intakes as high as 11
 mg/day (0.16 mg/kg-day)  may not cause any adverse effects in adult humans. Additional evidence, based
 on a study where women received daily supplements of 15 mg manganese for 90 days, suggests a safe
 level as high as 15 mg/day (Davis and Greger, 1992).

    A review of acute animal toxicity studies indicates that manganese has a low to moderate oral
 toxicity.  For example, the oral dose of manganese compounds at which 50% of rats died is in the range
 of 400-2,000 mg/kg. While some animal studies have also reported developmental and reproductive
 effects at high doses for certain manganese compounds, most data from oral exposure suggest that
 manganese has a low developmental toxicity.

    EPA has calculated a Reference Dose (RfD), or an estimate of a daily exposure via ingestion to the
human population that is likely to be safe, for manganese. The RfD for manganese in food is 0.14 mg/kg-
 day, based on dietary surveys which have reported daily manganese intake of 10 mg in average 70 kg
 adults without adverse effects.  As a precautionary measure for drinking water, EPA recommends
applying a modifying factor (MF) of 3 to yield a vahie of 0.047 mg/kg-day. One concern addressed by
this MF is the potential for humans to absorb greater levels of manganese by drinking water during early
morning, when the gut is empty, than by exposure in food.
                                             22

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Preliminary Regulatory Determination Support Document for Manganese
November, 2001
    There is no information available regarding the tfarcinogenicity of manganese in humans; animal
studies have reported mixed results.  The USEPA classified manganese as Group D, or not classifiable as
to human carcraogenicity. The Reference Concentration (RfC), an estimate of dairy exposure via
inhalation that is likely to be safe, formanganese is 5 x 10"5 mg/ra3 (USEPA, 1998c). The RfC was
derived using data from two epidemiological studies of workers exposed to manganese dioxide dust in an
occupational setting (Roels et al., 1987; Roels et ai,  1992).

4.3 Relative Source Contribution

    Relative source.contribution analysis compares the magnitude of exposures expected via consumption
of drinking water with those estimated for other relevant media such as food, air, arid soil. Occurrence
data for manganese provides the basis for estimating the amounts of manganese ingested via drinking
water in the exposed population. According to the National Inorganic and Radionuclide Survey (MRS)
data, the median and 99th percentile concentrations for manganese in ground water public water supplies
are above the MRL of 0.001 mg/L. This is not surprising considering the ubiquity of manganese hi the
earth's crust

    Taking the median concentration of detections from the NIRS data (0.01 mg/L), and assuming a dairy
intake of 2 L of drinking water by a 70 kg adult, the  average daily dose would be 2.8 x 10"4 mg/kg-day.
The corresponding dose for a 10 kg child consuming 1 L/day of drinking water would be 1.0 x 10"3
mg/kg-day.  These values are lower than the levels that the IOM (2001) considers to be safe and adequate.
The IOM has determined that a daily intake of 2.3 mg manganese for men and 1.8 mg for women is
adequate, while the daily adult intake expected from drinking water is 0.02 mg manganese.  The IOM also
determined that a daily intake of 1.9 mg manganese is adequate for boys and 1.6 mg is adequate for girls,
while the daily intake expected from drinking water is 0.01 mg for children (IOM, 2001). The National
Research Council proposed even higher recommended intakes of manganese: their Estimated Safe and
Adequate Daily Dietary Intake (ESADDI) for manganese is 2-5 mg for adults (NRC, 1989).

4.4 Sensitive Populations

    Potentially sensitive sub-populations include the elderly, pregnant women, iron-deficient individuals,
and individuals with impaired liver function. Because excretion by the liver is the primary route of
manganese elimination, individuals with impaired liver function may be especially susceptible to
manganese toxicity (Layrargues et al., 1998). Infants and neonates, whose capacity for excretion through
the bile is not fully developed, may also be potentially susceptible to manganese toxicity (Fechter, 1999).
Although animal studies have indicated an increased potential in neonates for gastrointestinal absorption
of manganese, as well as decreased excretion potential, the degree to which these findings apply to human
infants is unknown. There are no data to indicate that children are more sensitive to manganese than
adults. Those who are iron deficient may also experience greater susceptibility to manganese absorption
and toxicity (Finley, 1999; Finley et al., 1994).
                                              23

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 Preliminary Regulatory Determination Support Document for Manganese
November, 2001
 4.5 Exposure and Risk Information

    Estimates of exposed populations were described in the occurrence section of this document.
 National population estimates for manganese exposure were derived using summary statistics from the
 NIRS, in addition to supplemental surface water occurrence data, that was separately submitted to EPA
 from five States.

    Based on available data, approximately 47.5 million people are served by ground water public water
 systems with detections above the minimum reporting level (MRL). Furthermore, an estimated 4.0
 million people (4.6% of the population) are served by ground water with levels above one-half the HRL
 of 0.30 mg/L.  In addition, an estimated 2.3 million people (2.6% of the population) are served by ground
 water with levels above the HRL.

    Considering that manganese is an essential nutrient which is commonly found in normal diets, the
 estimated daily exposure to manganese from public water systems is far below the expected daily intake
 from diet When average daily intakes from drinking water are compared with intakes from food, air and
 soil, drinking water accounts for a relatively small proportion of manganese intake. On the basis of these
 observations, the impact of regulating manganese concentrations in drinking water on health risk
 reduction is likely to be small.

 4.6 Conclusion

    While there is evidence that manganese may have adverse health effects in humans at high doses
 through inhalation, studies indicate that oral ingestion at levels commonly found in western diets have no
 noticeable adverse effects. In addition, because manganese is an essential nutrient,  concern over potential
 toxic effects from high oral exposure must be balanced against concern for adverse  effects from
 manganese deficiency. Through a special study of contaminant occurrence in ground water systems
approximately 2.3 million people nationwide (2.6 % of the U.S. PWS population-served). However, the
HRL concentration is far less than the average daily intake of manganese through non-water sources. It is
therefore unlikely that manganese in drinking water will occur at concentrations that are of public health
concern or that regulation represents a meaningful opportunity for health risk reduction hi persons served
by public water systems. All preliminary CCL regulatory determinations and further analysis will be
presented in the Federal Register Notice.
5.0  TECHNOLOGY ASSESSMENT

   If a determination has been made to regulate a contaminant, SDWA requires development of
proposed regulations within 2 years of making the decision. It is critical to have suitable monitoring
methods and treatment technologies to support regulation development
                                            24

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Preliminary Regulatory Determination Support Document for Manganese
November, 2001
5.1 Analytical Methods

    The availability of analytical methods does not influence EPA's determination of whether or not a
CCL contaminant should be regulated. However, before EPA actually regulates a contaminant and
establishes a Maximum Contaminant Level (MCL), there must be an analytical method suitable for
routine monitoring. Therefore, EPA needs to have approved methods available for any CCL regulatory
determination contaminant before it is regulated with an NPDWR, These methods must be suitable for
compliance monitoring and should be cost effective, rapid, and easy to use. Manganese can be measured
by several well-documented analytical methods (see Table 5-1).

Table 5-1: Analytical Methods for Manganese
Method
EPA 200.7
SM3120B
EPA 200.8
SM3111B
EPA 200.9
SM3113B
Type
Inductively Coupled
Plasma Optical
Emission Spectrometry
(ICP)/Atomic Emission
Spectrometry
ICP/Atomic Emission
Spectrometry
ICP/Mass Spectrometry
Atomic Absorption,
direct aspiration
Stabilized Temperature
Graphite Furnace AA
Spectrometry
Atomic Absorption,
Furnace
Method Detection
Limit Gig/L)
1.0
Estimated Detection
Limit (EDL) 2.0
0.02
Instrument Detection
Level (IDL) 10 Optimum
cone, range 100-10,000
0.3
EDL 0.2 Optimum cone.
range 1-30
 5.2 Treatment Technology

    Treatment technologies also do riot influence the determination of whether or not a contaminant
 should be regulated. But, before a contaminant can be regulated with an NPDWR, treatment technologies
 must be readily available. Manganese is one of three inorganic contaminants listed as Regulatory
 Determination Priorities on the CCL. The treatment data for these inorganic compounds was obtained
 from EPA's technology and cost documents, the Office of Research and Development's National Risk
 Management Research Laboratory (NRMRL) Treatabiliry Database, and published studies. The
 technologies reviewed include conventional treatment, ion exchange, reverse osmosis, lime softening, and
 chemical precipitation.
                                              25

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  Preliminary Regulatory Determination Support Document for Manganese
November, 2001
     Conventional treatment usually includes pre-treatment steps of chemical coagulation, rapid mixing
  and flocculabon, followed by floe removal via sedimentation or flotation. After clarification, the water is
  then filtered. Common filter media include sand, and dual- and tri-media (e.g., silica sand, garnet sand or
  anthracitic coal).
  specific
  	                ,                     -cj-	,.. - -VAHM^VU jbMuwi>*iuu pjLvru/0 uiai uiuu mpiEV
  species by electrostatic attraction.  As water containing contaminant ions passes through a column of resin
  beds, charged ions on the resin surface are exchanged for the contaminant species in the water.

     Reverse osmosis (RO) is similar to other membrane processes, such as ultrafilteation and
  nanofiltration, since water passes through a semi-permeable membrane. However, in the case of RO the
  principle involved is not filtration. Instead,  it involves the use of applied hydraulic pressure to oppose the
  osmotic pressure across a non-porous membrane, forcing the water from the concentrated solution side to
  thedilute solution side. The water does not travel through pores, but rather dissolves into the membrane
  disuses across, then dissolves out into the permeate. Most inorganic and many organic contaminants are
  rejected by the membrane and will be retained in the concentrate.

     In the lime-softening process, the pH of the water being treated is raised sufficiently to precipitate
  calcium carbonate and, if necessary, magnesium hydroxide.  Calcium and magnesium ions in water cause
 hardness. After mixing, flocculation, sedimentation, and pH readjustment, the softened water is filtered.

     Results of a preliminary technology assessment and review indicate that all of the above-mentioned
 techniques remove manganese from water. However, data indicate that chemical precipitation is the most
 effective option.



 6.0  SUMMARY AND CONCLUSIONS-DETERMINATION OUTCOME

    Three statutory criteria are used to guide the determination of whether regulation of a CCL
 contaminant is warranted: 1) the contaminant may adversely affect the health of persons; 2) the
 contaminant is known or is likely to occur in public water systems with a frequency, and at levels of
 public health concern; and 3) regulation of the contaminant presents a meaningful opportunity for health
 nsk reduction for persons served by public water systems. As required by SDWA, a decision to regulate
 a contaminant commits the EPA to proposal of a Maximum Contaminant Level Goal (MCLG) and
 promulgation of a National Primary Drinking Water Regulation (NPDWR) for the contaminant   A
 decision not to regulate a contaminant is considered a final Agency action and  is subject to judicial
 review. The Agency can choose to publish a Health Advisory (a nonregulatory action) or other guidance
 for any contaminant on the CCL that does not meet the criteria for regulation.

    There is evidence that manganese may have adverse health effects hi humans at high doses through
 inhalation, most importantly as a neurotoxin (producing ataxia, anxiety, dementia, a "mask-like" face
 involuntary movements, or a syndrome similar to Parkinson's disease). Nevertheless, oral exposure at
 levels common in Western diets is not known to produce adverse health effects. In addition, because
manganese is an essential nutrient, concern over potential toxic effects from high oral exposure must be
balanced against concern for adverse effects from manganese deficiency. Potentially sensitive
                                             26

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Preliminary Regulatory Determination Support Document for Manganese
November, 2001
subpopulations include the elderly, pregnant women, iron-deficient individuals, and individuals with
impaired liver function. Manganese is not a known carcinogen.

    Manganese is a naturally, occurring element that constitutes approximately 0.1% of the earth's crust.
Industrially, manganese compounds are produced in the United States from manganese ore and are in
widespread use in the steel, fertilizer and water treatment industries. Releases have been reported since
1988 in all 50 States. Monitoring data indicate that low-level manganese occurrence in ambient waters
and bed sediments monitored by the USGS NAWQA program is ubiquitous, with detections approaching
100% of surface water sites and greater man 62% of ground water sites.  Stream bed sediments and
aquatic biota tissues show detections of 100% by sample and by site. Although manganese detection
frequencies are high in ambient waters, stream bed sediments, and aquatic biota tissue, manganese
occurrence at levels of public health concern is low.

    Manganese has been detected in ground water public water system (PW S) samples collected through
the MRS study.  Occurrence estimates are relatively high with approximately 68% of all sampled PWSs
showing detections, indicating that manganese is present in PWSs that serve about 55% of the national
population. Exceedances of the HRL of 0.30 mg/L affect 2.6% of the population, or approximately 2.3
million people nationally. The 99* percentile concentration of all samples is 0.63 mg/L. Additional
SDWA compliance data from the States of Alabama, California, Illinois, New Jersey, and Oregon,
including both ground water and surface water PWSs, were examined through independent analyses and
also show substantial levels of manganese occurrence.

    The levels of manganese frequently detected in PWSs are far below the average daily intake of
manganese through non-water sources: for example, the median concentration of detects in the NIRS
survey is 0.01 mg/L, while studies have indicated that for a 70 kg adult, a daily manganese intake of 10
mg through diet presents no adverse effect.

    Because manganese ingestion is not known to present adverse health effects at low levels, and
because drinking water contributes only a small portion of normal oral intake, it is unlikely that regulation
of manganese in drinking water would represent a meaningful opportunity for health risk reduction in
persons served by public water systems. Preliminary CCL regulatory determinations and further analysis
will be presented in the Federal Register Notice.
                                              27

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Preliminary Regulatory Determination Support Document for Manganese
November, 2001
                                        References

Agency for Toxic Substances and Disease Registry (ATSDR). 1997.  Toxicological profile for
    manganese (update). Draft for public comment Atlanta: Agency for Toxic Substances and Disease
    Registry. 201 pp.

ATSDR. 2000. Toxicological profile for manganese (update). Draft for public comment. Atlanta:
    Agency for Toxic Substances and Disease Registry.

Davis, C.D. and J.L. Greger. 1992. Longitudinal changes of manganese-dependent superoxide dismutase
    and other indexes of manganese and iron status in women. Am.J. Clin.Nutr.  55(3):747-752  (as
    cited in ATSDR, 2000).

Drever, James I.  1988. The Geochemistry of natural-waters. Second Edition. Englewood Cliffs, NJ:
    Prentice Hall. 437pp.

Fechter, L.D.  1999. Distribution of manganese in development. Neurotoxicology. 20:197-201.

Finley, J.W.  1999. Manganese absorption and retention by young women is associated with serum
    ferritin concentration. Am. J. Clin. Nutr. 70:37-43.

Finley, J.W., P.E. Johnson and L.K. Johnson.  1994. Sex affects manganese absorption and retention by
    humans fiom a diet adequate in manganese. Am. J. Clin. Nutr. 60(6):949-955.

Greger, J.L.  1999. Nutation versus toxicology of manganese in humans: evaluation of potential
    biomarkers.  Neurotoxicology. 20:205-212.

Institute of Medicine (IOM). 2001. Dietary Reference Intakes for Vitamin A,  Vitamin K, Arsenic, Boron,
    Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium and Zinc: A
    Report of the Panel on Micronutrients, Subcommittees on Upper Reference Levels of Nutrients and of
    Interpretation and Use of Dietary Reference Intakes, and the Standing Committee on the Scientific
    Evaluation of Dietary Reference  Intakes, Food and Nutrition Board, Institute of Medicine.
    Washington, DC: National Academy Press (prepublication version). Available on the Internet at:
    http://www.nap.edu/catalog/10026.html Accessed January 25,2001.

 Layrargues, G.P., C. Rose, L. Spahr, et al. 1998; Role of manganese in the pathogenesis of portal-
    systemic encephalopathy. Metab. Brain Dis. 13(4):311-317.    

 Leahy, P.P., and T.H. Thompson. 1994.  Hie National Water-Quality Assessment Program. US
    Geological Survey Open-File Report 94-70. 4 pp. Available on the Internet at:
    http://watCT.usgs.gov/nawqa/NAWQA.OFR94-70.html Last updated August 23,2000.

 National Research Council. 1989. Recommended dietary allowances.  Tenth Edition.  Washington, D.C.:
    National Academy Press.  302pp.

 Roels, H., R. Lauwerys, P. Genet, et al. 1987. .Relationships between external and internal parameters of
    exposure to manganese in workers from a manganese oxide and salt producing plant. Am. J. Ind.
    Med. 11:297-305  (as cited in USEPA, 1999).
                                               29

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Preliminary Regulatory Determination Support Document for Manganese
November, 2001
Roels, H.A., P. Ghyselen, JJ>. Buchet, et al. 1992.  Assessment of the permissible exposure level to
    manganese in workers exposed to manganese dioxide dust. Br. J. Ind. Med. 49(i):25-34 (as cited in
    USEPA, 1999).

Ryker, S J. and AJC Williamson. 1999. Pesticides in public supply wells ofWashington State. US
    Geological Survey Fact Sheet 122-96.

United States Environmental Protection Agency (LFSEPA). 1996. Emergency planning and community
    right-to-know section 313, list of toxic chemicals. 45 pp. Available on the Internet at
    http://www.epa.gov/tri/chemls2.pdf Last modified March 23,2000. Link to site afc
    http://www.epa.gov/tri/chemical.htm

USEPA. 1998a. Title III list of lists: Consolidated list of chemicals subject to the Emergency Planning
    and Community Right-to-knaw Act (EPCRA) and Section 112(r) of the Clean Air Act, as Amended.
    EPA Report 550-B-98-017. 36pp.

USEPA. 1998b. Announcement of the Drinking Water Contaminant Candidate List; Notice. Federal
    Register 63, no. 40 (2 March): 10273.

USEPA. 1998c. Guidelines for Neurotoxicity Risk Assessment.  Federal Register 63, no. 93 (14 May):
    26926.

USEPA. 1999. A Review of contaminant occurrence in public-water systems. Office of Water. EPA
    Report 816-R-99-006. 78pp.

USEPA. 2000a. TRI explorer: are year-to-year changes comparable? Washington, D.C.: USEPA.
    Available on the Internet at: www.epa.gov/triexplorer/yearsum.htm Last modified May 5,2000.

USEPA. 2000b. TRI explorer: trends. Washington, D.C.: USEPA.  Available on the Internet at:
    http://www.epa.gov/triexplorer/trends.htm. Last modified May 5,2000.

USEPA. 2000c. The Toxic release inventory (TRI) and factors to consider when using TRI data.
    Washington, D.C.: USEPA. Available on the Internet at: http://www.epa.gov/tri/tri98/98over.pdf.
    Last modified August 11,2000. Link to site at: http://www.epa.gov/tri/tri98

USEPA. 2000d. What is the toxic release inventory! Washington, D.C.: USEPA. Available on the
    Internet at: http://www.epa.gov/tri/general.htm  Last modified February 28,2000.

USEPA. 2000e. Water industry baseline handbook. Second Edition (Draft). Washington, D.C: USEPA.

USEPA. 2000 Regulatory matrix of TRI chemicals in other federal programs. Washington, D.C.:
    USEPA. Available on the Internet at: www.epa.gov/tri/chemicals.hmi Last modified 3/23/00.

USEPA. 2001. Health effects support document for Manganese. External review draft. Office of
    Water. EPA report 815-R-01-022. 154pp.

USGS. 2000. Mineral commodity summaries, February, 2000 - manganese. Reston, VA: United States
    Geological Survey. Available on the Internet at:
    htto^/niuierals.usgs.gov/nimerds/pubs/commodity/manganese/420300.pdf
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Preliminary Regulatory Determination Support Document for Manganese
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USGS. 2001.  USGS national water quality assessment data warehouse.  Reston, VA: United States
    Geological Survey. Available on the Internet at: http://infotrek.er.usgs.gov/pls/nawqa/nawqa.home
    Last updated April 19,2001.
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Preliminary Regulatory Determination Support Document for Manganese
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                    Appendix A: Abbreviations and Acronyms

ATSDR          - Agency for Toxic Substances and Disease Registry
AWWA          -American Water Works Association
CAS             - Chemical Abstract Service
CCL             - Contaminant Candidate List
CDC             -Center for Disease Control and Prevention
CEC             - cation exchange capacity            '
CERCLA        - Comprehensive Environmental Response, Compensation & Liability Act
CWS            - Community Water System
Eh              -oxidation-reduction potential
EPA             - Environmental Protection Agency
EPCRA          - Emergency Planning and Community Right-to-Know Act
ESADDI         - estimated safe and adequate daily dietary intake
FR              - Federal Register
g/mol            -grams per mole
HRL             -HealthReference Level
IOC             - inorganic compound
IOM             - Institute of Medicine
IRIS             -Integrated Risk Information System
K^.              -organic carbon partition coefficient
K^,             - octanol-water partitioning coefficient
L               -liter
LOAEL          - lowest observed adverse effect level
MCL            - maximum contaminant level
. MCLG          - maximum contaminant level goal
MDL            - method detection limit
MF             - modifying factor
mg              - milligram
mg/kg-day       - milligram per kilogram per day
mmHg          - millimeter mercury
MMT           - methylcyclopentadienyl manganese tricarbonyl
MRL            - Minimum Reporting Level
NAWQA        - National Water Quality Assessment Program
NDWAC        - National Drinking Water Advisory Council
NIRS            - National Inorganic and Radionuclide Survey
 nm              - nanometer
 NOAEL         - no observed adverse effect level
 NPDES          - National Pollution Discharge Elimination System
 NPDWR        - National Primary Drinking Water Regulation
 NRC            - National Research Council
 NRMRL    .    -National Risk Management Research Laboratory
 NTNCWS        - Non-Transient Non-Community Water System
 OGWDW        - Office of Ground Water and Drinking Water
 OMB             - Office of Management and Budget
 ORD             -Office of Research and Development
 OSHA           - Occupational Safety and Health Administration
 PEL              - permissible exposure limit
 pH               - the negative log of the concentration of H* ions
 ppm              - part per million
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Preliminary Regulatory Determination Support Document for Manganese
                                                           November, 2001
PWS
RfC
RfD
RO
RSC
SARA Title HI
SDWA
SDWIS/FED
SMCL
SOC
TRI
UCM
UCMR
USEPA
USGS
VOC
"g
>MCL
>MRL
 Public Water System
- reference concentration
 reference dose
- reverse osmosis
- relative source contribution
 Superfund Amendments and Reauthorization Act
- Safe Drinking Water Act
- the Federal Safe Drinking Water Information System
- Secondary Maximum Contaminant Level
- synthetic organic compound
- Toxic Release Inventory
- Unregulated Contaminant Monitoring
- Unregulated Contaminant Monitoring Regulation/Rule
- United States Environmental Protection Agency
- United States Geological Survey
- volatile organic compound
- micrograms
- percentage of systems with exceedances
- percentage of systems with detections
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