Northeast Regional Mercury Total Maximum Daily Load 

Connecticut Department of Environmental Protection 

Maine Department of Environmental Protection 

Massachusetts Department of Environmental Protection 

New Hampshire Department of Environmental Services 

New York State Department of Environmental Conservation 

Rhode Island Department of Environmental Management 

Vermont Department of Environmental Conservation 

New England Interstate Water Pollution Control Commission 

October 24, 2007
Northeast Regional Mercury TMDL – October 2007 ii 

Contents 

Contents.......................................................................................................................................................ii

Tables..........................................................................................................................................................iv

Figures.........................................................................................................................................................iv

Acknowledgements .....................................................................................................................................v

Executive Summary ...................................................................................................................................vi

Abbreviations ...........................................................................................................................................xiii

Definition of Terms..................................................................................................................................xvi

1 Introduction..............................................................................................................................................1

1.1 Water Quality and Health Concerns...............................................................................................1

1.2 TMDL Requirements and Process ..................................................................................................1

2 Background Information.........................................................................................................................2

2.1 Fish Consumption Advisories..........................................................................................................2

2.2 Section 319 Nonpoint Source Assessments and Categorization of Atmospheric Deposition as a 

Nonpoint Source......................................................................................................................................3

2.3 Massachusetts’ TMDL Alternative and EPA Justification for Disapproval...............................4

2.4 Section 303(d) Listing for Mercury Impaired Waters – Category 5m.........................................5

2.5 Northeast Regional Commitment to Reducing Regional Sources of Mercury............................6

2.6 Control of In-State Sources not Sufficient to Meet Water Quality Standards............................7

3 Applicable Water Quality Standards and Fish Tissue Criteria...........................................................8

3.1 Assessment of Fish Contaminants...................................................................................................8

4 Fish Tissue Mercury Concentrations.....................................................................................................9

4.1 Fish Tissue Monitoring Dataset.......................................................................................................9

4.2 Areas of Elevated Concentration...................................................................................................11

5 Northeast Regional Approach...............................................................................................................11

5.1 Impaired Waters.............................................................................................................................11

5.2 Priority Ranking of Impaired Waterbodies .................................................................................12

5.3 Selection of Existing Fish Mercury Concentration Based on Standard Size Fish.....................13

5.4 Target Fish Mercury Concentration.............................................................................................15

5.5 Proportionality of Mercury Reductions........................................................................................16

6 Source Assessment .................................................................................................................................18

6.1 Northeast States Emissions Inventory...........................................................................................18

6.2 Atmospheric Deposition Modeling ................................................................................................22

6.3 Point Sources to Water ...................................................................................................................25

7 Development of a Regional Total Maximum Daily Load...................................................................26

7.1 TMDL Formulation........................................................................................................................26

7.2 Calculation of Existing Total Source Load (TSL)........................................................................27

7.3 Reduction Factor (RF)....................................................................................................................28

7.4 TMDL Calculation..........................................................................................................................29

7.5 Wasteload Allocation (WLA).........................................................................................................29

7.6 Load Allocations..............................................................................................................................30

7.6.1 Load Allocation Calculations..................................................................................................30

7.6.2 Necessary Reductions to Meet LA..........................................................................................31

7.7 Margin of Safety..............................................................................................................................33

7.8 Seasonal Variation and Critical Conditions.................................................................................34

7.9 Daily Load........................................................................................................................................34

8 Final TMDL............................................................................................................................................34

9 Implementation ......................................................................................................................................35
Northeast Regional Mercury TMDL – October 2007 iii 

9.1 State and Regional Implementation ..............................................................................................35

9.1.1 Implementation of Wasteload Allocation ..............................................................................35

9.1.2 Adaptive Implementation of Load Allocation .......................................................................36

9.2 Adaptive National Implementation ...............................................................................................38

10 Reasonable Assurances........................................................................................................................39

10.1 State Level Assurances .................................................................................................................39

10.2 National and International Assurances.......................................................................................44

11 Public Participation .............................................................................................................................45

12 References.............................................................................................................................................47

Appendix A: Northeast Waters Impaired Primarily by Atmospheric Deposition of Mercury .........50

Appendix B: Necessary Reductions to meet Water Quality Standards in Maine and Connecticut..57

Appendix C: Mean Mercury Concentrations at NPDES-Permitted Facilities Used in Calculating the 

Baseline Point Source Load......................................................................................................................66

Appendix D: State Mercury Reduction Plans........................................................................................72

Appendix E: Response to Comments......................................................................................................73
Northeast Regional Mercury TMDL – October 2007 iv 

Tables 

Table ES-1 Summary of Northeast Regional Mercury TMDL...................................................viii 

Table 2-1 Summary of Statewide Fish Consumption Advisories for Freshwaters..............................3 

Table 3-1 Water Quality Criteria and Fish Consumption Advisory Values for Mercury.......................8 

Table 4-1 Number of Fillet Mercury Samples Included and Mean Length-Standardized Mercury 

Concentration for Fish Species Analyzed in the NERC Dataset..................................................10 

Table 4-2 Standard Lengths and Mercury Concentrations of Selected Freshwater Fish Species in the 

Northeast.................................................................................................................10 

Table 5-1 Northeast Waterbodies Impaired Primarily by Atmospheric Deposition of Mercury................12 

Table 6-1 1998 Northeast Regional Mercury Emissions Inventory..............................................21 

Table 6-2 Modeled Mercury Atmospheric Deposition in 1998 and 2002 for the Northeast 

Region.....................................................................................................................22 

Table 6-3 Mercury Point Sources to Water.........................................................................26 

Table 9-1 Northeast State Mercury Control Programs for Coal-Fired Utilities................................37 

Table 10-1 Comparison Between 1998 and 2002 Regional Mercury Emissions Inventories................40 

Table 11-1 Public Participation Actions Undertaken by the Northeast States.................................45 

Table A-1 Massachusetts Freshwaters Impaired Solely by Atmospheric Mercury............................51 

Figures 

Figure 5-1 Relationship of Fish Length and Fillet Mercury Concentration for Smallmouth Bass, by 

State.......................................................................................................................14 

Figure 5-2 Cumulative Distribution of Mercury Concentrations in Northeast Fish............................16 

Figure 6-1 Breakdown of Major Sources of Northeast Regional Mercury Emissions.........................19 

Figure 6-2 Major Sources of National Mercury Emissions in 1996.............................................20 

Figure 6-3 Total Regional Modeled Mercury Deposition in 1998 and 2002 Based on REMSAD 

Modeling.................................................................................................................24 
Northeast Regional Mercury TMDL – October 2007 v 

Acknowledgements

This TMDL was developed by a technical committee made up of representatives of each of the Northeast 

states and the New England Interstate Water Pollution Control Commission (NEIWPCC). Team 

members include Traci Iott and Paul Stacey (Connecticut DEP); Andrew Fisk and Barry Mower (Maine 

DEP); Rick Dunn, Russell Isaac, and C. Mark Smith (Massachusetts DEP); Gregg Comstock, Robert 

Estabrook, and Peg Foss (New Hampshire DES); Jay Bloomfield, Dick Draper, Ron Entringer, and Scott 

Quinn (New York State DEC); Scott Ribas and Elizabeth Scott (Rhode Island DEM); Tim Clear and Neil 

Kamman (Vermont DEC); and Beth Card and Susannah King (NEIWPCC). The team acknowledges the 

support of the NEIWPCC Executive Committee, as well as support from their agencies, and assistance 

from other divisions and agencies in the development of the TMDL. The team also acknowledges the 

assistance of the Northeast States for Coordinated Air Use Management (NESCAUM), who provided 

vital information for this effort. 

The TMDL was modeled closely after the Minnesota Pollution Control Agency’s Minnesota Statewide 

Mercury Total Maximum Daily Load and thus many of the concepts and ideas are applied in this 

document. The Northeast Regional Mercury TMDL project team acknowledges the excellent work put 

forth by Minnesota and thanks them for their contribution to reducing mercury in the environment. 
Northeast Regional Mercury TMDL – October 2007 vi 

Executive Summary 

Mercury is a potent neurotoxin that poses risks to human health. Exposure to this toxic metal occurs when 

humans consume fish that contain mercury’s most toxic form, methylmercury. The majority of mercury 

in the environment is released into the air, but it reaches waterbodies through atmospheric deposition. In 

order to protect their populations from the harmful effects of mercury, states issue fish consumption 

advisories that provide information on the types and quantities of fish that can be safely consumed. Six of 

the seven Northeast states have statewide fish consumption advisories for mercury for all freshwaters. 

However, fish consumption advisories are intended to be temporary until pollution can be reduced to 

levels that allow for safe fish consumption. 

This Total Maximum Daily Load (TMDL) document outlines a strategy for reducing mercury 

concentrations in fish in Northeast fresh waterbodies so that water quality standards can be met. This will 

require reductions from mercury sources within the Northeast region, U.S. states outside of the region, 

and global sources. In the Northeast, the majority of mercury pollution is a result of atmospheric 

deposition. Thus, the TMDL is based primarily on reduction of atmospheric deposition, which can be 

achieved through reductions in anthropogenic mercury emissions. 

Impaired Waters 

In the Northeast, over 10,000 lakes, ponds, and reservoirs, and over 46,000 river miles are listed as 

impaired for fish consumption primarily due to atmospheric deposition of mercury. Many of these 

waterbodies are listed due to statewide fish consumption advisories for mercury. Section 303(d) of the 

Clean Water Act requires that states develop TMDLs for impaired waters by establishing the allowable 

pollutant loading from all contributing sources at a level necessary to achieve the applicable water quality 

standards. The TMDL allocates load between point sources (wasteload allocation) and nonpoint sources 

(load allocation). 

Existing and Target Fish Tissue Concentrations

A regional fish tissue database was used to calculate mean, 80th, and 90th percentile mercury 

concentrations for standard length fish. Four fish species were considered, but smallmouth bass was 

chosen as the target fish. The 80th and 90th percentile mercury concentrations for a standard length (32 

cm) smallmouth bass are 0.860 ppm and 1.14 ppm, respectively. The TMDL was calculated as the 90th

percentile mercury concentration for smallmouth bass, which equates to the 96th percentile of all fish. 

Although the 90th percentile fish concentration has been chosen as the TMDL target, in order to address 

uncertainty, all TMDL calculations are shown for the range from the 80th to 90th percentile fish tissue 

concentration. Because this TMDL is for seven states with different criteria for fish tissue mercury, the 

EPA fish tissue criterion for methylmercury of 0.3 ppm is used as the initial target fish tissue 

concentration for the regional TMDL. Two states, Connecticut and Maine, use fish tissue criteria more 

stringent than 0.3 ppm that will be achieved in later stages of TMDL implementation. TMDL 

calculations based on these criteria are provided in Appendix B. It should be noted that the goal of this 

TMDL is to use adaptive implementation to achieve a target of 0.3 ppm for Massachusetts, New 

Hampshire, New York, Rhode Island, and Vermont; 0.2 ppm for Maine, and 0.1 ppm for Connecticut. 

Such an approach will allow all of the Northeast states to meet or exceed their designated uses. 

Mercury Sources

In a general sense, regional sources of mercury pollution include wastewater discharges and atmospheric 

deposition. The mercury wastewater load was estimated using a regional median mercury effluent 

concentration calculated from all appropriate available mercury effluent data in the region and the sum of 
Northeast Regional Mercury TMDL – October 2007 vii 

design flows for NPDES permitted facilities in the region (excluding facilities that primarily discharge 

cooling water or discharge to marine waters). Based on a regional median effluent concentration of 7.7 

ng/l and sum of design flows of 13,322 MGD, the wastewater load is estimated to be 141 kg/yr. 

The 1998 Northeast Regional Mercury Emissions Inventory provides estimates of mercury emissions 

from a number of sources in the Northeast and is considered the baseline for purposes of establishing 

needed reductions. 1998 was prior to the enactment of significant mercury reduction requirements in the 

region and therefore represents an appropriate baseline to correspond with measured fish tissue 

concentrations. Total emissions for the region are reported as 12,494 kg/yr. Modeling of 1998 mercury 

emissions data produces an estimate of the amount of mercury deposited to the region from regional, 

national, and international sources. Based on this modeling, the baseline mercury atmospheric deposition 

load to the region is 6,506 kg/yr, with 4,879 kg attributable to anthropogenic sources. 

Calculation of TMDL

The steps used to calculate the TMDL are outlined in Table ES-1. Using the existing fish concentration 

1.14 ppm, and the initial target fish tissue mercury concentration of 0.3 ppm, a reduction factor of 0.74 

was calculated. It should be noted that the TMDL was calculated in a way that sets multiple target 

endpoints that are geographically based. The goal of this TMDL is to use adaptive implementation to 

achieve a target of 0.3 ppm for Massachusetts, New Hampshire, New York, Rhode Island, and Vermont; 

0.2 ppm for Maine, and 0.1 ppm for Connecticut. The total existing source load was calculated from the 

point source load (wastewater discharges) and nonpoint source load (atmospheric deposition based on 

modeling of mercury emissions), and is equal to 6,647 kg/yr. The TMDL was then calculated using the 

total source load and the reduction factor. The wasteload allocation was determined by keeping the 

wastewater contribution equal to the same percentage as it was in the total source load. The load 

allocation was calculated by subtracting the wasteload allocation from the TMDL and then was divided 

between natural1

 and anthropogenic sources. Because over 97 percent of the total load is due to 

atmospheric deposition, reductions focus on the load allocation. Necessary reductions were divided into 

three phases, 1998-2003, 2003-2010, and 2010 on, and were also allocated between in-region and out-ofregion sources. 

 

1

 Natural sources of mercury include volcanoes, geologic deposits, and volatization from the ocean. 
Northeast Regional Mercury TMDL – October 2007 

Table ES-1: Summary of the Northeast Regional Mercury TMDL

Value (80th percentile) Value (90th percentile) Unit Source 

Background Information Area of the Region (includes CT, MA, ME, NH, NY, RI, VT) 307,890 km2 NESCAUM Proportion of Deposition due to Anthropogenic Sources 0.75 Kamman and EngstrTMDL Base Year 1998 TMDL Phase I Implementation Period 1998-2003 TMDL Phase II Implementation Period 2003 -2010 TMDL Phase III Implementation Period 2010 on Water Quality Goal Target Fish Mercury Concentration 0.30 ppm EPA Fish Tissue CriExisting Level in Fish (32 cm Smallmouth Bass) 0.86 1.14 ppm NERC Dataset, RIDReduction Factor (RF) [(Existing Level - Target Level)/Existing Level] 0.65 0.74 Base Year Loadings Point Source Load (PSL) - Wastewater Discharge 141 kg/yr PCS data Modeled Atmospheric Deposition 5,405 kg/yr 

NESCAUM, based oInventory 

Modeled Natural Atmospheric Deposition1 526 kg/yr 

NESCAUM, based oInventory 

Modeled Anthropogenic Atmospheric Deposition, Anthropogenic Nonpoint Source Load (ANPSL) 4,879 kg/yr 

NESCAUM, based oInventory 

Natural Nonpoint Source Load (NNPSL) Atmospheric Deposition (Based on Deposition is 25% Natural and 75% Anthropogenic) 1,626 kg/yr Total Nonpoint Source Load (NPSL) [ANPSL + NNPSL] 6,506 kg/yr Total Source Load (TSL) [NPSL + PSL] 6,647 kg/yr Percentage of TSL due to PSL 2.1% Loading Goal 

1 The global contribution to the atmospheric deposition modeling includes some natural sources of mercury. The modeled natural atmo

subtracted from the total modeled atmospheric deposition to avoid double counting of the natural contribution. 
Northeast Regional Mercury TMDL – October 2007 

Loading Goal [TSL x (1-RF)] 2,319 1,749 kg/yr TMDL Wasteload Allocation (WLA) [Keep at 2.1% of TSL] 49 37 kg/yr Load Allocation (LA) [Loading Goal - WLA] 2,269 1,712 kg/yr Natural Load Allocation1 (NLA) 1,626 1,626 kg/yr Anthropogenic Load Allocation (ALA) [LA - NLA] 643 86 kg/yr Overall Reductions to Meet TMDL Necessary In-Region Atmospheric Deposition Reductions to Meet ALA 1,816 2,055 kg/yr Necessary Out-of-Region Atmospheric Deposition Reductions to Meet ALA 2,420 2,738 kg/yr Percent Reduction in Anthropogenic Atmospheric Deposition Necessary to Meet ALA 86.8% 98.2% TMDL Implementation Phase I (50%) In-Region Portion of ANPSL 2,092 kg/yr 

NESCAUM, based oinventory 

In-Region Reduction Target (50% from baseline) 1,046 kg/yr Necessary In-Region Atmospheric Deposition Reductions to meet Phase I Target 1,046 kg/yr In-Region Atmospheric Deposition Reductions Achieved in Phase I 1,549 kg/yr 

NESCAUM, based oemissions inventorie

Remaining In-Region Atmospheric Deposition Reductions Necessary to Meet Phase I Target 0 kg/yr Remaining In-Region Atmospheric Deposition Reductions Necessary to Meet Final TMDL 267 506 kg/yr Out-of-Region Portion of ANPSL 2,787 kg/yr 

NESCAUM, based oinventory 

Out-of-Region Reduction Target (50% from baseline) 1,394 kg/yr 

1Deposition due to natural sources remains the same over time, so the natural load allocation is equal to the existing natural deposition. 
Northeast Regional Mercury TMDL – October 2007 

Necessary Out-of-Region Atmospheric Deposition Reductions to Meet Phase I Target 1,394 kg/yr Additional Out-of-Region Atmospheric Deposition Reductions to Meet Final TMDL 1,026 1,345 kg/yr TMDL Implementation Phase II (75%) In-Region Portion of ANPSL 2,092 kg/yr 

NESCAUM, based oinventory 

In-Region Reduction Target (75% from baseline) 523 kg/yr Necessary In-Region Atmospheric Deposition Reductions to meet Phase II Target 1,569 kg/yr In-Region Atmospheric Deposition Reductions Achieved in Phase I 1,549 kg/yr 

NESCAUM, based oemissions inventorie

Remaining In-Region Atmospheric Deposition Reductions Necessary to Meet Phase II Target 20 kg/yr Remaining In-Region Atmospheric Deposition Reductions Necessary to Meet Final TMDL 247 486 kg/yr Out-of-Region Portion of ANPSL 2,787 kg/yr 

NESCAUM, based oinventory 

Out-of-Region Reduction Target (75% from baseline) 697 kg/yr Necessary Out-of-Region Atmospheric Deposition Reductions to Meet Phase II Target 2,090 kg/yr Additional Out-of-Region Atmospheric Deposition Reductions to Meet Final TMDL 330 648 kg/yr TMDL Implementation Phase IIIThe Phase III timeline and goal will be set following re-evaluation of mercury emissions, deposition, and fish tissue concentrations in 

remaining reductions will be addressed as follows: Major air point sources will be addressed through the application of more stringent 

and/or emission limits, economically and technically feasible/achievable, taking into account advances in the state of air pollution con

transferable technologies used by other sources, to achieve maximum emission reductions. Emissions from area sources will be contr

feasible using best management practices and pollution prevention approaches. It should be noted that the goal of this TMDL is to use achieve a target of 0.3 ppm for Massachusetts, New Hampshire, New York, Rhode Island, and Vermont; 0.2 ppm for Maine, and 0.1 papproach will allow all of the Northeast states to meet or exceed their designated uses. 
Northeast Regional Mercury TMDL – October 2007 
Northeast Regional Mercury TMDL – October 2007 xii 

Regional TMDL Atmospheric Deposition Goal

To meet the initial TMDL target of 0.3 ppm, the mercury TMDL for the region is 1,750 kg/yr, or 4.8 

kg/d. This is divided into a wasteload allocation of 38 kg/yr and a load allocation of 1,712 kg/yr. The 

load allocation for natural sources is 1,626 kg/yr, leaving an anthropogenic load allocation of 86 kg/yr. 

Implementation of this goal is divided into three phases. Phase I, from 1998 to 2003, sets a goal of 50 

percent reduction, from in-region and out-of-region sources, from the 1998 baseline. With in-region 

reductions of 1,549 kg/yr achieved as of 2002, the in-region reduction goal has been exceeded. Phase II, 

from 2003 to 2010, sets a goal of 75 percent reduction. This leaves 20 kg/yr for in-region reductions 

necessary to meet this target. In 2010, mercury emissions, deposition, and fish tissue concentration data 

will be re-evaluated in order to assess progress and set a timeline and goal for Phase III to make 

remaining necessary reductions to meet water quality standards. Not enough data are currently available 

to accurately assess reductions achieved by out-of-region sources. 

Adaptive Implementation

The TMDL is structured to separately show loading goals for in- and out-of-region sources and is 

expected to be implemented adaptively in order to evaluate the calculated necessary percent reduction 

from anthropogenic sources. The Northeast states have already reduced deposition by approximately 74 

percent between 1998 and 2002 and have reasonable assurances (including product legislation and 

emissions controls) in place to assure attainment of Phase II goals on an adaptive basis. To meet out-ofregion goals, Northeast states recommend EPA implement plant-specific MACT limits for mercury under 

Section 112(d) of the Clean Air Act to control power plant emissions by 90 percent by cost-effective and 

available technologies. The Northeast region’s ability to achieve the calculated TMDL allocations is 

dependent on the adoption and effective implementation of national and international programs to achieve 

necessary reductions in mercury emissions. Given the magnitude of the reductions required to implement 

the TMDL, the Northeast cannot reduce in-region sources further to compensate for insufficient 

reductions from out-of-region sources. 
Northeast Regional Mercury TMDL – October 2007 xiii 

Abbreviations 

ALA – Anthropogenic Load Allocation 

ANCOVA – Analysis of Covariance 

ANOVA – Analysis of Variance 

ANPSL – Anthropogenic Nonpoint Source Load 

C – Concentration 

CAA – Clean Air Act 

CAMR – Clean Air Mercury Rule 

CEC – Commission for Environmental Cooperation 

CT DEP – Connecticut Department of Environmental Protection 

d – Day 

dscm – Dry Standard Cubic Meter 

EFMC – Existing Fish Mercury Concentration 

EGU – Electrical Generating Unit 

EPA – United States Environmental Protection Agency 

Hg – Chemical symbol for mercury 

ICI – Industrial/Commercial/Institutional 

kg - Kilogram 

l – Liter 

lb - Pound 

LA – Load Allocation 

MACT – Maximum Achievable Control Technology 

MAP – Mercury Action Plan 

MassDEP – Massachusetts Department of Environmental Protection 

ME DEP – Maine Department of Environmental Protection 

mg – Milligram 
Northeast Regional Mercury TMDL – October 2007 xiv 

MGD – Million Gallons per Day 

MMP – Mercury Minimization Plan 

MOS – Margin of Safety 

MTF – Mercury Task Force 

MWC – Municipal Waste Combustor 

MWI – Medical Waste Incinerator 

NARAP – North American Regional Action Plan 

ng - Nanogram 

NEG-ECP – Conference of the New England Governors and Eastern Canadian Premiers 

NEI – National Emissions Inventory 

NEIWPCC – New England Interstate Water Pollution Control Commission 

NERC – Northeastern Ecosystem Research Cooperative 

NESCAUM – Northeast States for Coordinated Air Use Management 

NEWMOA – Northeast Waste Management Officials’ Association 

NH DES – New Hampshire Department of Environmental Services 

NLA – Natural Load Allocation 

NNPSL – Natural Nonpoint Source Load 

NPDES – National Pollutant Discharge Elimination System 

NPSL – Nonpoint Source Load 

NSRC – Northeastern States Research Cooperative 

NYS DEC – New York State Department of Environmental Conservation 

oz - Ounce 

PDNS – Proportion of Deposition due to Natural Sources 

POTW – Publicly Owned Treatment Works 

ppb – Parts per Billion 

ppm – Parts per Million 
Northeast Regional Mercury TMDL – October 2007 xv 

PSL – Point Source Load 

Q - Flow 

RF – Reduction Factor 

RI DEM – Rhode Island Department of Environmental Management 

SSI – Sewage Sludge Incinerator 

TBtu – Trillion British Thermal Units 

TFMC – Target Fish Mercury Concentration 

TMDL – Total Maximum Daily Load 

TSL – Total Source Load 

VT DEC – Vermont Department of Environmental Conservation 

UNEP – United Nations Environment Programme 

WLA – Wasteload Allocation 

WWTF – Wastewater Treatment Facility 

yr – Year 
Northeast Regional Mercury TMDL – October 2007 xvi 

Definition of Terms

Atmospheric Deposition – the mass transfer of gaseous, aerosol, or particulate contaminant species from 

the atmosphere to the earth’s surface 

de minimis – insignificant; a Latin expression meaning “of minimum importance” 

Dry Deposition – mass transfer of gaseous, aerosol, or particulate contaminant species from the 

atmosphere to the earth’s surface in the absence of precipitation 

Fish Consumption Advisory – guidelines issued by state public health agencies on amounts of and 

frequency that certain fish can be eaten; can be statewide, regional, or waterbody-specific. 

Gaseous Mercury – mercury occurring in the dry-phase, as either reactive gaseous mercury (Hg2+) or 

gaseous elemental mercury (Hg0

) 

Nonpoint Source Pollution – diffuse sources of pollution to water from land use or atmospheric 

deposition of pollutants 

Northeast States – Connecticut, Maine, Massachusetts, New Hampshire, New York State, Rhode Island, 

and Vermont 

Point Sources – wastewater discharges and all other pollutant sources that enter the receiving water 

through a pipe or channel 

Standard Length Fish – a term used to mean that fish tissue concentrations have been adjusted to a 

standard length, in this case the dataset wide mean length 

TMDL – total maximum daily load – the maximum amount of a pollutant that a waterbody can receive 

and still meet water quality standards 

Wet Deposition – mass transfer of dissolved gaseous or particulate contaminant species from the 

atmosphere to the earth’s surface via precipitation
Northeast Regional Mercury TMDL – October 2007 1 

1 Introduction 

1.1 Water Quality and Health Concerns 

Mercury is a toxic metal that is released to the environment through natural and human processes. Most 

commonly, the gaseous and particulate forms are released to the atmosphere, which are then deposited 

onto land and water in precipitation. Once in the water, the mercury can be converted to its most toxic 

form, methylmercury, which accumulates in fish and aquatic organisms. Humans are exposed to 

methylmercury and subject to its associated health effects when they consume contaminated fish. The 

challenge posed by mercury is significant, and the New England Interstate Water Pollution Control 

Commission (NEIWPCC) and its member states1

 are increasingly involved in this complicated issue. 

In the Northeast, fish consumption advisories that have resulted from elevated levels of mercury in certain 

fish species are of great concern. The vast majority of this mercury can be attributed to atmospheric 

deposition. The major challenge that the Northeast states face is the lack of available options to control 

out-of-state sources of atmospheric deposition, despite nearly a decade of work that has resulted in 

regional reductions in mercury emissions and discharges of approximately 70 percent. The mercury 

TMDL provided in this document has been developed by the Northeast states in an effort to address 

mercury impaired waters and region-wide fish consumption advisories. The ultimate goal of the Northeast 

states is to control all sources of mercury, both in-region and out-of-region, to levels where water quality 

standards for fish consumption are met. 

1.2 TMDL Requirements and Process 

The TMDL process is straightforward: states are required by the Clean Water Act to identify water bodies 

that are failing to meet their water quality standards. The regulations then require that any impaired 

waterbody be analyzed to determine the daily amount, or load, of a pollutant it can assimilate without 

violating the state’s applicable water quality standards. That daily load is then broken down into an 

amount attributed to point sources and nonpoint sources, and specifies where and when reductions will be 

made so the load is not exceeded. 

Specifically, Section 303(d) of the Federal Clean Water Act requires each state to (1) identify waters for 

which effluent limitations normally required are not stringent enough to attain water quality standards, 

and (2) to establish TMDLs for such waters for the pollutant of concern. TMDLs may also be applied to 

waters threatened by excessive pollutant loadings. The TMDL establishes the allowable pollutant loading 

from all contributing sources at a level necessary to achieve the applicable water quality standards. A 

TMDL must account for seasonal variability and include a margin of safety (MOS) to account for 

uncertainty of how pollutant loadings may impact the receiving water’s quality. 

The TMDL report and attached documents are submitted to the U.S. Environmental Protection Agency 

(EPA) as a TMDL under Section 303(d) of the Federal Clean Water Act, 40 CFR 130.7. The regulations 

do not in anyway preclude multi-state or regional TMDLs and in-fact EPA Regions 1 and 2 have had 

success in approving TMDLs that are prepared by more than one state. In accordance with those same 

regulations, it is understood that the Regional Administrator shall approve or disapprove the loadings 

provided not later than 30 days. It is also understood that if the Regional Administrator disapproves the 

loadings he shall establish loadings within 30 days of the disapproval. The states are aware that if the 

 

1

 NEIWPCC’S member states include Connecticut, Maine, Massachusetts, New Hampshire, New York, Rhode 

Island, and Vermont. 
Northeast Regional Mercury TMDL – October 2007 2 

Regional Administrator approves the loadings being submitted in the attached documents, they are then 

required to incorporate those loadings into their water quality management plans. 

2 Background Information 

2.1 Fish Consumption Advisories 

States issue fish consumption advisories to inform the public about the recommended fish consumption 

levels for their waters. Advisories provide information on limiting or avoiding consumption of particular 

species of fish from specific waterbodies, a group of waterbodies, or an entire state. Nationwide, 48 

states currently have fish consumption advisories in place, including all of the Northeast states. 

For the most part, fish consumption advisories are issued by each state’s public health agency and vary 

from state to state. All of the New England states have statewide advisories for all freshwaters and New 

York State has waterbody-specific advisories as well as regional advisories, including blanket advisories 

for all waters in the Adirondack and Catskill regions. A summary of statewide fish consumption 

advisories for sensitive and general populations is shown in Table 2-1 below. 
Northeast Regional Mercury TMDL – October 2007 3 

Table 2-1 Summary of Statewide Fish Consumption Advisories1

 for Freshwaters 

State Sensitive2

 Population General Population 

CT No more than 1 meal/month of fish other than 

trout caught in any Connecticut fresh 

waterbody; no limits on consumption of trout. 

1 meal/week for all freshwater fish other than 

trout caught in any Connecticut fresh 

waterbody; no limits on consumption of trout. 

MA Avoid eating fish from any fresh waterbodies. Limit consumption of affected species to 2 

meals/month. 

ME For all freshwater fish other than brook trout 

and land locked salmon, do not eat any meals; 

for trout and salmon, 1 meal/month. 

For all freshwater fish other than brook trout 

and land locked salmon, 2 meals/month; for 

trout and salmon, 1 meal/week. 

NH 1 meal/month of freshwater fish (8 oz for 

pregnant and nursing women, 3 oz for 

children under 7); when eating bass and 

pickerel, limit consumption to fish 12 inches 

or less in length. 

Four 8 oz meals/month of freshwater fish; 

when eating bass and pickerel, limit 

consumption to fish 12 inches or less in length. 

NY Do not eat any fish from specific listed 

waterbodies. Avoid pickerel, northern pike, 

smallmouth bass, largemouth bass, walleye, 

and yellow perch from Adirondack Mountain 

and Catskill Mountain waters. 

Except where otherwise provided in listed 

waters, no more than 1 meal/week of fish taken 

from New York State freshwaters. 

RI Do not eat any fish from Rhode Island ponds, 

lakes, or rivers. 

1 meal/month of most freshwater fish, avoid 

bass, pickerel, and pike. 

VT walleye – eat none 

lake trout, smallmouth bass, chain pickerel, 

American eel – 1 meal/month 

largemouth bass, northern pike – 2 

meals/month 

brook trout, rainbow trout, brown trout, 

yellow perch – 3-4 meals/month 

brown bullhead, pumpkin seed – no advisory 

all other freshwater fish – 2-3 meals/month 

walleye – 1 meal/month 

lake trout, smallmouth bass, chain pickerel, 

American eel – 3 meals/month 

largemouth bass, northern pike – 6 

meals/month 

brook trout, rainbow trout, brown trout, yellow 

perch, brown bullhead, pumpkin seed – no 

advisory 

all other freshwater fish – 9 meals/month 

1

Some advisories are based on mercury and other fish contaminants. 

2

Sensitive populations are defined as follows: 

CT: Women who are pregnant, women who plan to become pregnant within one year, women who are 

nursing, children under six 

MA: Pregnant women, women of child-bearing age, nursing mothers, children under 12 

ME: Pregnant and nursing women, women who may get pregnant, children under 8 

NH: Pregnant and nursing women, women who may get pregnant, children under 7 

NY: Women of childbearing age, infants, children under 15 

RI: Young children, women who are pregnant, nursing, or planning to have a baby in the coming year 

VT: Women of childbearing age (particularly pregnant women, women planning to get pregnant, and 

breastfeeding mothers) and children under 6 

2.2 Section 319 Nonpoint Source Assessments and Categorization of Atmospheric Deposition as a 

Nonpoint Source 

A great majority of the nation’s remaining water quality problems can be attributed to nonpoint source 

pollution. The 2000 U.S. EPA National Water Quality Inventory Report found that nonpoint source 

pollution is the leading source of impairment to the nation’s rivers, lakes, and coastal waters (U.S. EPA 
Northeast Regional Mercury TMDL – October 2007 4 

2002). Section 319 was added to the Clean Water Act in the amendments of 1987 in order to address 

nonpoint source pollution. Section 319 highlights three main strategies for addressing polluted runoff by: 

(1) requiring states to prepare assessments of nonpoint source problems; (2) requiring that states develop 

management programs to address the problems identified in these assessments; and (3) creating a grant 

program that allows EPA to fund state programs for nonpoint source assessment and control. 

Furthermore, the state assessment reports are required to identify waters impaired or threatened by 

nonpoint source pollution, to identify the categories, subcategories, or individual sources contributing to 

the nonpoint source pollution problem, and to recommend the best management practices or measures to 

be used to control each category or subcategory of source (Clean Water Act, Section 319(a)(b)(h)and(i)). 

Section 319 addresses nonpoint sources of water pollution. EPA publications classify atmospheric 

deposition as nonpoint source water pollution with statements such as: “Atmospheric deposition and 

hydromodification are also sources of nonpoint source pollution”(U.S. EPA 1994). Out-of-state mercury 

sources, namely coal-fired power plants, therefore fall within Section 319. Currently, New York State 

and each of the New England states has an approved Section 319 plan covering portions of its navigable 

waters, including portions impaired by mercury pollution. 

2.3 Massachusetts’ TMDL Alternative and EPA Justification for Disapproval 

Over the past several years, the Northeast states have worked closely with EPA Region 1 on several 

TMDL innovations projects, including a project to develop regional recommendations for accurately 

reporting impaired waters in Category 4b of the Integrated Report. The Integrated Report is a single 

document that integrates the reporting requirements of Clean Water Act Sections 305(b) and 303(d). 

States place their waters in one of five categories based on what available data say about the condition of 

the waterbody. Category 4b includes impaired waters that do not require a TMDL because other pollution 

control requirements are stringent enough to implement the applicable water quality standard and is more 

recently described in the Guidance for 2006 Assessment, Listing and Reporting Requirements Pursuant to 

Sections 303(d), 305(b) and 314 of the Clean Water Act, which was issued by EPA on July 29, 2005. The 

New England States and New York State all provided input on this approach through the TMDL 

innovations process, and endorsed the concept. In fact, the approach used by the Massachusetts 

Department of Environmental Protection (MassDEP) described below was similarly used by the Maine 

Department of Environmental Protection (ME DEP) and Rhode Island Department of Environmental 

Management (RI DEM) in their 2004 303(d) submissions. For the 2004 listing cycle, none of the 

approaches were approved by EPA. 

In 2004 the Commonwealth of Massachusetts submitted to EPA a document titled “A TMDL Alternative 

Regulatory Pathway Proposal for the Management of Selected Mercury Impaired Waters.” The document 

was a supplement to MassDEP’s 2004 Integrated List and sought to document that other pollutant control 

requirements were in place such that water quality standards would be met and development of a TMDL 

would not be required. Massachusetts described how it was effectively implementing a comprehensive 

management plan to address in-state sources of mercury and that a combination of federal, regional, and 

state controls on mercury were and are the most effective way of addressing water quality impairments 

due mainly to atmospheric deposition. Examples of these in-state controls include but are not limited to 

pollution prevention programs and regulatory controls on mercury emitters such as municipal waste 

combustors, dentists, and schools. The plan focused on a goal of virtual elimination of mercury sources in 

Massachusetts and the entire New England region. 

In a letter dated June 21, 2006, EPA disapproved MassDEP’s alternative regulatory pathway to move 90 

lakes and ponds impaired solely by atmospheric deposition from Category 5 to Category 4b of the state’s 

Integrated List of Waters. EPA cited that the estimates in the proposal and its own estimates indicate that 
Northeast Regional Mercury TMDL – October 2007 5 

a significant percentage of mercury from atmospheric deposition comes from international sources for 

which there are no state or federal controls. As a result EPA determined that the approach did not meet 

the necessary requirements for demonstrating that the actions taken will result in the attainment of water 

quality standards in a reasonable amount of time. Specifically, in its response to MassDEP, EPA stated 

the following: 

“EPA regulations require states to list water quality segments still requiring TMDLs where 

certain controls including other pollution control requirements ‘required by local, State, or 

Federal authority’ are insufficient to achieve applicable water quality standards. (See 40 CFR 

§130.7 (b)1(iii)).” 

“While Massachusetts describes its strong mercury reduction program, as well as the New 

England wide mercury reduction efforts, Massachusetts has not demonstrated that other pollution 

control requirements exist that are sufficient to implement the Commonwealth’s water quality 

standards for mercury within a reasonable amount of time. See 40 CFR 130.7(b)(1)(iii). In spite 

of the strong state, regional, and federal mercury reduction efforts, it will be difficult to achieve 

water quality standards, due in part to the contributions from non-U.S. sources (i.e., the global 

reservoir).” 

It was determined by EPA in its disapproval documentation that the “best way to address mercury 

impaired waters is within the context of the 303(d) listing process...” As such, the states in the Northeast 

have put their energies and efforts into that process with this regional TMDL. 

2.4 Section 303(d) Listing for Mercury Impaired Waters – Category 5m 

Waters are to be listed in Category 5 of the Integrated Water Quality Monitoring and Assessment Report 

if “available data and/or information indicate that at least one designated use is not being supported or is 

threatened, and a TMDL is needed (U.S. EPA 2005a).” This category represents Clean Water Act Section 

303(d) – waters that are listed as impaired and are to be reviewed and approved by EPA. 

On March 8, 2007, EPA released guidance on utilizing a modified Category 5, known as Category 5m, 

for waters on the 303(d) list that are impaired primarily by atmospheric deposition of mercury. The 

guidance on Listing Waters Impaired by Atmospheric Mercury Under Clean Water Action Section 303(d) 

describes use of subcategory “5m” as a voluntary approach to listing waters impaired by mercury from 

atmospheric sources. Category 5m is EPA’s recognition that even if a state has a comprehensive mercury 

management approach, when water quality impairments are primarily caused by atmospheric deposition, 

in-state controls alone cannot lead to attainment. Category 5m could serve as a placeholder for states to 

defer TMDL development until later in the schedule. The approach, however, does not and cannot 

statutorily remove the obligation for a TMDL to be developed at some point in time, and EPA literature 

on this approach specifically notes that the agency is not suggesting that TMDLs are inappropriate tools 

for mercury impairments. 

The information regarding Category 5m shared at the annual meeting of the Association of State and 

Interstate Water Pollution Control Administrators in August 2006 specified that multi-state efforts toward 

regional goals or targets are encouraged. It is in the spirit of regional cooperation and goal setting that this 

TMDL has been prepared and it is done so with the understanding that the Clean Water Act requires it. 
Northeast Regional Mercury TMDL – October 2007 6 

2.5 Northeast Regional Commitment to Reducing Regional Sources of Mercury 

The Conference of the New England Governors and Eastern Canadian Premiers (NEG-ECP) is an 

organization of the governors of the six New England states and the premiers of the five Eastern Canadian 

provinces1

. The governors and premiers collaborate on regional issues and take action on policy areas 

including the environment, energy, economic development, trade, security, and ocean issues. 

In June 1997, the NEG-ECP charged its Committee on the Environment to develop a regional Mercury 

Action Plan (MAP). Subsequently, a draft framework for the MAP was developed by representatives of 

the states and provinces, and then finalized and agreed upon by the NEG-ECP in June 1998. The MAP 

identifies steps to address those aspects of the mercury problem in the region that are within the region’s 

control or influence and sets an overall regional goal to virtually eliminate the discharge of anthropogenic 

mercury into the environment to ensure that serious or irreversible damage attributable to these sources is 

not inflicted upon human health and the environment (Committee on the Environment of the Conference 

of the New England Governors and Eastern Canadian Premiers 1998). 

The six action items set forth in the MAP: 1) established a regional task force to implement the plan; 2) 

specified emissions limits for major mercury sources that are considerably more stringent than federal 

requirements; 3) supported pollution prevention efforts to reduce mercury use in products and increase 

collection and recycling of mercury-added products where environmentally preferable alternatives do not 

exist; 4) directed state and provincial agencies to implement outreach and education programs about 

mercury; 5) supported coordination of mercury research and environmental monitoring efforts to track 

results; and 6) called for retirement of the U.S. federal mercury stockpile. Implementation of the MAP 

has been very successful. All of the New England states have developed and implemented numerous 

legislative and regulatory actions to address mercury sources. 

In accordance with the MAP, a regional Mercury Task Force (MTF) was formed by representatives of the 

New England states and Eastern Canadian provinces. This group meets annually and reports on progress 

in meeting the goals of the MAP. The MAP originally set forth a goal of 50 percent reduction of regional 

mercury emissions by 2003, and then in 2001 set another interim goal of 75 percent reduction by 2010. 

In 2003, the MTF reported that the goal of 50 percent had been exceeded with reductions achieved 

amounting to approximately 55 percent2

 (Conference of New England Governors and Eastern Canadian 

Premiers 2003). This overall reduction was primarily due to an 84 percent reduction in emissions from 

municipal waste combustors (MWCs), a 98 percent reduction in emissions from medical waste 

incinerators (MWIs), and a 93 percent reduction in emissions from chlor-alkali facilities (NESCAUM and 

the New England Governors and Eastern Canadian Premiers Mercury Task Force 2004). The 2005 status 

report indicates that substantial progress has already been made toward the 2010 goal (The Conference of 

New England Governors and Eastern Canadian Premiers Mercury Task Force and The Committee on the 

Environment of the Conference of New England Governors and Eastern Canadian Premiers 2005). 

In August 2003, the MTF adopted a regional goal that 50 percent of dental offices in the region would 

install amalgam separators by the end of 2005. This goal has been exceeded and the MTF has established 

new goals of 75 percent separation installation by the end of 2007 and 95 percent by the end of 2010. In 

2005, it was estimated that states had the following rates of amalgam separator installation: Connecticut – 

65 percent, Maine – 95 percent, Massachusetts – 74 percent, New Hampshire – 95 percent, Rhode Island 

– 25 percent, and Vermont 15 percent (The Conference of New England Governors and Eastern Canadian 

 

1

 New Brunswick, Newfoundland & Labrador, Nova Scotia, Prince Edward Island, and Québec 

2

 The MAP Regional Reductions of 55 percent from 1998 emissions and the 74 percent reductions shown in Section 

7.7.2 for the Phase I implementation for in-region differ because the MAP looks at reductions for the New England 

states and the Eastern Canadian provinces, whereas this TMDL covers the New England states and New York. 
Northeast Regional Mercury TMDL – October 2007 7 

Premiers Mercury Task Force and the Committee on the Environment of the Conference of New England 

Governors and Eastern Canadian Premiers 2005). Installation of amalgam separators is instrumental in 

reducing mercury in wastewater. 

While New York State is not a member of the NEG-ECP, they were active participants in the 1998 

regional mercury study and in the development of the MAP. New York State remains committed to 

reducing mercury in their state and has established its own Mercury Task Force to coordinate mercury 

issues within their state. Additionally, New York State participates in regional efforts coordinated by 

NEIWPCC, the Northeast States for Coordinated Air Use Management (NESCAUM), and the Northeast 

Waste Management Officials’ Association (NEWMOA). Similar to the New England states, New York 

State has enacted legislation to control use of mercury in products, require installation of amalgam 

separators, and has set strict emissions limits for MWCs. As a result, mercury emissions in New York 

State from this sector decreased more than 85 percent from 1998 to 2002, contributing to a decrease of 

approximately 63 percent in overall state mercury emissions in the same time period. 

As of 2006, all of the Northeast states have passed legislation to address mercury in products. Individual 

laws and requirements vary by state, but legislation addresses bans on disposal of mercury-added 

products, bans on sale or distribution of mercury-added novelties and measuring devices, requirements for 

installing amalgam separators, requirements for labeling of mercury-added products, prohibition of 

primary and secondary schools purchasing or using mercury, removal of mercury switches from 

automobiles, and requirements on recycling of mercury-added products. Connecticut, Massachusetts, 

Maine, New Hampshire, and New York have all passed legislation to reduce mercury emissions limits 

from coal-fired utilities. Detailed information on individual state legislation and programs is provided in 

Section 10.1. Controls on mercury-containing products contribute to reductions in mercury in wastewater 

and mercury emissions from MWCs and MWIs. 

The Northeast has also been the center of a number of mercury-related research efforts. Project such as 

the Biodiversity Research Institute’s Mercury Connections (Evers 2005), the Hubbard Brook Research 

Foundation’s Mercury Connections (Driscoll, et al. 2007), and EPA’s Connecticut River Fish Tissue 

Study (Hellyer 2006) have documented the mercury problem in the Northeast and the efforts that have 

taken place in the region to reduce mercury. 

Because the Northeast states have made nationally significant reductions to in-state sources of mercury as 

a result of their regional action plan, and have collectively developed a peer-reviewed dataset of fish 

tissue contaminants, it was determined that a regional TMDL would be the most effective strategy to 

work toward eliminating the need for fish consumption advisories in the Northeast. 

2.6 Control of In-State Sources not Sufficient to Meet Water Quality Standards 

Using 1998 emissions data, atmospheric deposition modeling undertaken by NESCAUM estimates that 

43 percent of the anthropogenic mercury deposited in the Northeast is attributed to sources within the 

region. The remaining 57 percent can be attributed to sources outside of the region, from other U.S. states 

and international sources. When modeling was undertaken with 2002 emissions data, it was estimated 

that 19 percent of anthropogenic mercury deposited in the region originated from within the region and 81 

percent can be attributed to out-of-region sources. As discussed in the previous section, the Northeast 

states are already aggressively addressing mercury sources within their region, and they have additional 

enforceable controls coming into effect that will demonstrate reductions are continuing in addition to the 

reductions shown here by the 2002 data. But, in-region reductions are not sufficient to make the fish safe 

to eat. More stringent national and international controls are necessary to reduce out-of-region sources to 

the level that will allow for safe fish consumption. 
Northeast Regional Mercury TMDL – October 2007 8 

3 Applicable Water Quality Standards and Fish Tissue Criteria 

Two of the Northeast states, Maine and Massachusetts, have adopted methylmercury fish tissue criteria as 

part of their water quality standards. For all toxic pollutants not otherwise listed, Massachusetts uses the 

recommended criteria published by EPA pursuant to Section 304(a) of the Clean Water Act. This holds 

true for mercury, so Massachusetts uses the EPA methylmercury fish tissue criterion of 0.3 ppm. 

Connecticut, New Hampshire, New York, Rhode Island, and Vermont use water quality standards that 

consider exposure to mercury through fish consumption expressed as a water column concentration. In 

addition, Connecticut has narrative criteria for protection of human health that reference criteria 

established by the state department of public health. Although not all states have adopted a fish tissue 

criterion as part of their water quality standards, each state has a fish tissue concentration that they 

consider as a part of their basis for developing fish consumption advisories. Water quality criteria and fish 

consumption advisory values are shown in Table 3-1 below. 

Table 3-1 Water Quality Criteria and Fish Consumption Advisory Values for Mercury 

 CT ME MA NH NY RI VT 

Fish tissue concentration (ppm) 

0.1 0.2 * 0.3 * 0.3 1.0 0.3 0.3 

Water quality criterion (μg/l) 0.051 NA NA 0.051 0.0007 0.15 0.15 

*These numbers are fish tissue concentrations that have been adopted as fish tissue criteria in state water quality 

standards. The numbers for the other states in this row are the fish tissue concentrations that these states consider as 

part of their basis for developing fish consumption advisories. 

Although not all states have adopted water quality criteria based on fish tissue concentrations, this TMDL 

analysis is based on use of a fish tissue concentration. Because fish tissue concentrations take into 

account bioaccumulation, they are more protective than water column concentrations. Use of a target fish 

tissue concentration of 0.1, 0.2, or 0.3 ppm will ensure that state water quality criteria based on water 

column concentrations are met. 

A water column concentration (WCC) can be calculated from a fish tissue criterion (FTC) and 

bioaccumulation factor (BAF) through the following equation: 

FTC = BAF x WCC 

A 2004 study of mercury biogeochemistry in Vermont and New Hampshire lakes (Kamman, et al. 2004) 

provides bioaccumulation factors ranging from 52,481/L to 1,023,293/L for yellow perch fillets with 

respect to epilimnetic total mercury. Analysis of regional fish tissue data indicates that smallmouth bass 

mercury concentrations can be approximately 1.5 to two times higher than for yellow perch (Kamman, et 

al. 2005). Therefore, using the high end of the range for yellow perch, bioaccumulation factors for 

smallmouth bass would range from 1,534,940/L to 2,046,586/L. Using the highest fish tissue 

concentration of 0.3 mg/kg and the above range for bioaccumulation factors for smallmouth bass, a WCC 

range of 0.0001 to 0.0002 μg/l is obtained. The range of WCCs calculated is lower than any of the WCCs 

used by the states. Therefore, use of a fish tissue criterion as a TMDL target ensures that water column 

criteria will be met if the TMDL fish tissue target is met. 

3.1 Assessment of Fish Contaminants 

For the most part, for listing purposes, states do not assess waters by measuring mercury in the water 

column, but rather monitor mercury in fish tissue. For states with methylmercury fish tissue criteria, if 

fish samples do not meet the criterion, the waterbody is listed as impaired for fish consumption. Where 
Northeast Regional Mercury TMDL – October 2007 9 

states do not have fish tissue criteria, specific waters or all waters for which fish consumption advisories 

have been issued are considered to be impaired for fish consumption use, subject to the state’s assessment 

and listing methodology. For the purpose of this TMDL, fish tissue concentrations in wet-weight fillets 

are considered the TMDL endpoint. 

4 Fish Tissue Mercury Concentrations

4.1 Fish Tissue Monitoring Dataset 

In 2000, the Northeast States Research Consortium (NSRC), then a program of the USDA Forest Service 

Northeastern Research Station, sponsored the establishment of a Northeast North American mercury 

workgroup (known as the Northeastern Ecosystem Research Cooperative (NERC) Mercury Consortium) 

to compile and analyze as large an assembly of mercury data as practical, from a wide variety of 

environmental matrices, focusing on freshwater ecosystems. A fish tissue database that covers the NSRC 

study region (Connecticut, Maine, Massachusetts, New Hampshire, New York, Vermont, eastern Ontario, 

Quebec, and the Canadian Atlantic Provinces) was assembled as part of this initiative (Evers and Clair 

2005). 

A group of scientists from the NERC Mercury Consortium assembled existing fish mercury databases 

from agencies and organizations in the study area, resulting in a database that spans the geographic range 

from 39.5 to 54.7 N latitude and 53.9 to 79.5 W longitude, which includes Connecticut, Maine, 

Massachusetts, New Hampshire, New York, and Vermont. Contributing datasets originated from 

monitoring programs carried out by provincial and state governments for the purpose of risk assessment, 

random probability surveys conducted within the United States, and other datasets derived from largescale research initiatives. NERC scientists collected geo-referenced datapoints from 24 research and 

monitoring projects to create an aggregate 19,815 datapoints (Kamman, et al. 2005). 

In order to be retained in the dataset, fish data had to meet a number of requirements. Only fish mercury 

measurements analyzed using cold-vapor atomic absorption or cold-vapor atomic fluorescence 

spectroscopy were retained. The fish had to be collected in 1980 or later. Data from the Great Lakes and 

St. Lawrence River were excluded because these waterbodies were outside the focus of the NSRC 

assessment. Only mercury concentrations derived from fish fillets or whole fish were retained (Kamman, 

et al. 2005). 

The dataset was subject to a series of validation checks to ensure data quality, including checks to detect 

outlier, mis-transcribed, or incorrect datapoints. Validity checks identified a number of datapoints with 

values that were either excessively high, presented in the wrong unit of measure, or mis-attributed to the 

wrong species. These datapoints were either corrected or removed from the database. Of the 19,178 

original records submitted to the database, 15,305 met screening criteria, passed validity checks, and were 

retained (Kamman, et al. 2005). 

The final dataset contains mercury measurements for 64 freshwater fish species with yellow perch and 

brook trout being the most prevalent species. Data were only analyzed for the 13 species that either had 

1000 or more mercury measurements, or were present in nine or more of the projects. The numbers of 

datapoints per state and arithmetic mean mercury concentrations for these 13 species are shown in Table 

4-1. (Kamman, et al. 2005) 

As the NERC dataset did not include data from Rhode Island, fish tissue data from this state were 

obtained so that they could be included in the TMDL. Rhode Island had data available for five of the 

species that were included in the NERC dataset. These data are also shown in Table 4-1. 
Northeast Regional Mercury TMDL – October 2007 10 

Table 4-1 Number of Fillet Mercury Samples Included and Arithmetic Mean Mercury 

Concentrations for Fish Species Analyzed 

Species Count of fillet mercury samples by state 

Arithmetic mean mercury 

concentration (ppm) 

Common name CT MA ME NH NY RI VT Total 

Yellow perch 60 221 828 1250 99 434 2892 0.391 

Largemouth bass 1 70 18 200 44 170 18 521 0.532 

Lake trout 14 369 44 427 0.405 

Smallmouth bass 4 24 19 172 61 5 46 331 0.641 

Chain pickerel 7 148 5 16 176 0.564 

Brown bullhead 1 34 5 41 19 49 26 175 0.152 

Walleye 64 64 128 0.416 

White perch 32 43 15 32 6 128 0.870 

White sucker 31 16 43 22 112 0.237 

Brown trout 5 10 34 11 60 0.165 

Brook trout 22 27 6 55 0.168 

Northern pike 1 22 24 47 0.461 

Landlocked salmon 3 8 10 21 0.319 

The NERC dataset is clearly appropriate for the development of a regional mercury TMDL due to its 

geographic coverage and the fact that is has already gone through both validation and peer-review 

processes. For the purpose of this TMDL, length-standardized mercury concentrations were calculated 

for four species, using a subset of the NERC dataset that excluded data from the Canadian provinces. The 

four species considered were smallmouth bass, largemouth bass, walleye, and yellow perch. Mean, 80th, 

and 90th percentile mercury concentrations for standard length fish were calculated for each of the four 

fish species. Characteristics for these fish are shown in Table 4-2 below. 

Table 4-2 Standard Lengths and Mercury Concentrations of Selected Freshwater Fish Species in 

the NERC dataset 

Species Standard 

Length 

(cm) 

Mean Hg 

Concentration 

(ppm) at Standard 

Length* 

80th percentile Hg 

Concentration 

(ppm) at Standard 

Length 

90th percentile Hg 

Concentration (ppm) 

at Standard Length 

Smallmouth bass 

(Micropterus 

dolomieu)

32 0.69 0.86 1.14 

Largemouth bass 

(Micropterus 

salmoides) 

36 0.61 0.90 1.05 

Yellow perch 

(Perca flavenscens) 

20 0.38 0.52 0.69 

Walleye (Sander 

vitreus) 

45 0.60 0.82 0.93 

*Standard lengths were derived as dataset-wide mean lengths. Means shown in this table differ from those in Table 

4-1 because arithmetic means are shown in Table 4-1 and length-standardized means are shown in Table 4-2. 
Northeast Regional Mercury TMDL – October 2007 11 

4.2 Areas of Elevated Concentration 

In the Northeast, there are known localized areas where elevated fish tissue concentrations, as compared 

to background regional levels, have been observed (Evers, et al. 2007). Typically, areas of elevated 

concentration are associated with natural conditions, such as enhanced watershed sensitivity, in 

combination with anthropogenic factors including water-level manipulation, enhanced deposition of acidforming precursors, and enhanced mercury deposition. These areas include the western Adirondack 

Mountains in New York, the Upper Connecticut River in New Hampshire and Vermont, the middle and 

lower Merrimack River in New Hampshire, the Upper Androscoggin River in Maine and New 

Hampshire, and the Western Upper Kennebec River in Maine (for more details, see Evers, et al. 2007). 

These sensitive areas are included in this TMDL, as implementation is expected to result in decreases in 

fish tissue concentrations in these areas. However, the response may vary from the rest of the region, so 

these areas will be more closely monitored during the implementation period. It is expected that 

monitoring will be conducted through regular state fish tissue monitoring programs (at the level that 

funding allows) as well as regional research projects. Because these areas are more sensitive to mercury 

deposition, it is possible that they may experience faster decreases in fish tissue concentrations. Adaptive 

implementation will allow for changes to the reductions planned for these areas if necessary. 

In addition, areas of elevated concentration can be a result of high levels of localized atmospheric 

deposition. This is the case for an area in northeastern Massachusetts where fish mercury concentrations 

are elevated as a result of high deposition in that area. Fish from this area are not included in the regional 

dataset and the regional TMDL will not cover this area. Waterbodies located in this area are identified in 

Table A-1 in Appendix A. However, it is anticipated that implementation of this TMDL will significantly 

reduce fish concentrations in this area and may possibly achieve standards in the future. MassDEP 

intends to closely monitor these waters and if necessary, address this area separately in the future. 

5 Northeast Regional Approach 

The entire Northeast region is impacted by local, regional, and global mercury deposition sources and 

shares the common problem of large contributions of mercury deposition from sources outside of the 

region. As a result, the region already has a long history of working together on mercury reduction efforts 

such as the NEG-ECP MAP. Although mercury deposition is not necessarily uniform across the entire 

region (see Figure 6-3), a shared interest in addressing mercury deposition and demonstrated success in 

regional efforts makes the case for a regional-scale TMDL. Furthermore, as detailed in Section 5.3, once 

the effect of fish length is accounted for, fish concentrations are relatively uniform across the region. 

5.1 Impaired Waters 

In the Northeast, there are a total of 10,192 lakes, ponds, and reservoirs, 24 river segments, and an 

additional 46,199 river miles impaired for fish consumption primarily due to atmospheric deposition of 

mercury. The breakdown for each state is shown below in Table 5-1. 

Connecticut, Maine, and New Hampshire all have statewide advisories, and use this as a basis for listing 

all freshwaters as impaired for fish consumption due to mercury. Massachusetts, Rhode Island, and 

Vermont also have statewide advisories, but they only list waters that have been assessed and found to be 

impaired on their lists of impaired waters. New York State does not have a statewide advisory, but has a 

large number of waterbodies listed as impaired for fish consumption due to atmospheric deposition of 

mercury. 
Northeast Regional Mercury TMDL – October 2007 12 

Appendix A contains the list of waterbodies covered by the TMDL for Massachusetts, New York, Rhode 

Island, and Vermont, based on those states’ Impaired Waters Lists. The appendix also includes the 

language from Connecticut’s, Maine’s, and New Hampshire’s lists that explains using the statewide 

advisory as a basis for listing. In these three states, there are a small number of waters that are impaired 

by mercury that is caused by a source other than atmospheric deposition. These waters are therefore not 

covered by this TMDL and are listed in the Appendix A as exceptions to the state’s listing of all 

freshwaters. For all states, only water designated as rivers, streams, lakes, reservoirs, and impoundments 

are included and waters designated as marine, estuarine, or ocean are not included. More details on these 

designations are provided in Appendix A. 

Table 5-1 Northeast Waterbodies Impaired Primarily by Atmospheric Deposition of Mercury 

State Lakes, Ponds, and Reservoirs Rivers 

Connecticut 2,259 5,376 miles 

Maine 5,782 31,199 miles 

Massachusetts 991,2 03 

New Hampshire 1,9454 9,624 miles 

New York 675 14 segments 

Rhode Island 19 06 

Vermont 217 10 segments 

Total 10,192 46,199 miles; 24 segments 

1

Those impaired solely due to atmospheric mercury deposition. 

2

20 of these waterbodies (see Appendix A for specific waterbodies) are not covered by this TMDL because they are 

located in local mercury deposition hotspots and will be addressed separately by MassDEP. 3

Massachusetts has additional river segments impaired due to local mercury sources that are not covered by this 

TMDL. 

4

Includes impoundments. 

5

Includes five segments of Lake Champlain counted as separate waterbodies. 6

Rhode Island has additional river segments impaired due to mercury. However, it has not yet been determined 

whether local sources not covered by this TMDL contribute to the impairment. 

7

Includes eleven segments of Lake Champlain counted as separate waterbodies. 

In addition to the impaired waters listed in Appendix A, the TMDL may, in appropriate circumstances, 

also apply to waterbodies that are listed for mercury impairment in subsequent Clean Water Act Section 

303(d) Lists of Impaired Waters. For such waterbodies, this TMDL may apply if, after listing the waters 

for mercury impairment and taking into account all relevant comments submitted on the Impaired Waters 

List, a state determines with EPA approval of the list that this TMDL should apply to future mercury 

impaired waterbodies. 

5.2 Priority Ranking of Impaired Waterbodies

Of the seven states included in this TMDL, two states have included priority rankings for mercuryimpaired waters on their 303(d) and Integrated Lists. New York State denotes waterbodies of high 

priority for TMDL development, but none of the New York State waterbodies included in this TMDL 

were denoted as high priority. Vermont prioritizes all impaired waterbodies as high (TMDL development 

in one to three years), medium (four to eight years), or low (eight or more years). All of the Vermont 

waterbodies included in this TMDL are categorized as high priority for TMDL development. While not 

all states have specifically designated priority rankings for their mercury impaired waters in their 303(d) 

reports or Integrated lists, they have all demonstrated that mercury reduction is a high priority through 

their regionally coordinated actions to reduce mercury sources to the environment by over 70 percent 

since 1998. This regional mercury TMDL is a continuation of this priority work. 
Northeast Regional Mercury TMDL – October 2007 13 

5.3 Selection of Existing Fish Mercury Concentration Based on Standard Size Fish 

To best utilize the extensive NERC dataset and make the strongest comparisons of fish mercury 

concentrations from different waterbodies and sampling years, mercury concentrations are calculated for 

a standard-length fish. Mercury concentration increases with both age and length, so when comparing 

mean concentrations from all fish, it is important to account for this relationship. Calculated fish mercury 

concentrations were statistically adjusted, using analysis of covariance (ANCOVA) to a nominal 

“standard-length” fish. The standard length was derived as the dataset-wide mean length for the species, 

and concentrations of standard-length fish were estimated using least-squares means, accounting for the 

Type III model sums-of-squares (Kamman, et al. 2005). From a statistical standpoint, this is the most 

appropriate approach in that variance in fish mercury attributable to length is minimized at the datasetwide mean length. It is recognized that many fish will be above the standard length and therefore higher 

in mercury. This is addressed by basing this TMDL analysis on the 90thpercentile of the distribution of all 

length-standardized fish evaluated. This is more protective than using a mean or median concentration 

value. 

In developing this TMDL, the states considered using four different species of fish for calculating 

necessary reductions (see Table 4-2). After examining data for all four species, it was decided that 

smallmouth bass should be the target fish, as it is the species that bioaccumulates mercury most 

efficiently (based on comparison of mean, 80th, and 90th percentile concentrations) and is ubiquitously 

distributed amongst the Northeast states. Use of this species will allow for the highest common level of 

protection. The majority of the fish in the regional dataset were collected in the early to mid 1990s and 

therefore concentrations used in this TMDL may be somewhat higher than if fish collection coincided 

with the 1998 timeframe of the emissions and deposition data. To address this uncertainty, the existing 

fish concentration is presented as a range from the 80th to 90th percentile mercury concentration. 

However, the target for purposes of implementing this TMDL is considered to be the 90th percentile 

mercury concentration. As shown in Table 4-1, the 80th and 90th percentile mercury concentrations based 

on the standardized length for smallmouth bass are 0.860 and 1.14 ppm, respectively1

. 

In order to justify the choice of regional target fish species, arithmetic mean tissue concentrations and 

counts of fish-tissue datapoints by state and by species where fish lengths were reported were examined 

(Table 4-1). This analysis indicated that while walleye may have been the optimum species to use due to 

its high concentration (and therefore conservative TMDL target), this species is only represented in two 

states (Vermont and New York), and therefore, a poor representative of the region. By contrast, yellow 

perch are sampled nearly everywhere, but are typically lower in fillet mercury. Had yellow perch been 

used as the endpoint species for this TMDL, there would not be assurance that higher-mercury fish would 

achieve compliance with water quality standards once the TMDL was implemented. Smallmouth bass are 

both relatively uniformly sampled across the states, and also quite high in fillet mercury, rendering this 

species nearly ideal as a target endpoint for this TMDL. Furthermore, when length-standardized mercury 

concentrations are examined, smallmouth bass have the highest mean and 90th percentile concentrations 

of all fish species analyzed. 

In addition, to ensure that data from one state would not bias the region wide TMDL target, variation in 

fillet-mercury concentrations by state was also examined. To do this analysis, the effect of fish length on 

fish mercury was accounted for. Accounting for the effect of fish length is critical in that fish mercury 

varies with length, and the lengths of fish represented by state monitoring databases is variable (ANOVA 

F325,5=31.8, p<0.001). Therefore this analysis of covariance was used to test the hypothesis that fish 

 

1

 No data from Rhode Island were included in the NERC dataset. However, Rhode Island data were examined and it 

was found that they are well-aligned with the NERC dataset. If Rhode Island data were included in the NERC 

dataset, it would not have changed the existing fish tissue concentration used in the TMDL. 
Northeast Regional Mercury TMDL – October 2007 14 

mercury varied as a function of the state in which the fish were originally sampled, while accounting for 

the effect of length, with the null hypothesis that fish mercury did not vary by state. Fish mercury data 

were log-transformed to account for non-normality in this parameter. 

Smallmouth bass fillet mercury did not vary by state (p=0.2250) despite significant variation with length 

(p<0.001; overall ANCOVA F325,6 = 38.2, P<0.001). The analysis captured fully 42 percent of the 

variance observed within the smallmouth bass fillet mercury dataset. This relationship can be seen in 

Figure 5-1. This analysis, coupled with the information shown by Table 4-1, indicates that smallmouth 

bass are relatively uniform in fillet mercury across the jurisdictions, are the highest-mercury fish for 

which data are available from most states subject to this TMDL, and are therefore most suited for the 

application of a regional TMDL. The lack of variation in fish tissue concentrations across the states 

(when length is accounted for) indicates that a regional-scale TMDL is appropriate. 

Figure 5-1. Relationship of Fish Length and Fillet Mercury Concentration (log ppm) for 

Smallmouth Bass, by State 

Regression lines were calculated by ANCOVA and show that when the effect of fish length is accounted for, fish 

mercury does not vary significantly by state. 

The goal of this TMDL is to protect human health, and therefore the existing and target fish 

concentrations were selected with this in mind. However, it should be noted that there are also concerns 

associated with mercury and piscivirous wildlife such as loons, eagles, and otters. Fish that feed high on 

the food web, such as the smallmouth bass, are more reflective of obligate apex piscivores like loons and 

eagles, therefore by targeting the TMDL to smallmouth bass, both ecological and human health are 

protected by ensuring that the prey upon which obligate piscivores feed will be low enough in mercury to 

preclude risk to the most mercury-sensitive of aquatic biota. 
Northeast Regional Mercury TMDL – October 2007 15 

5.4 Target Fish Mercury Concentration 

As discussed previously, the Northeast states consider different fish mercury concentration guidance 

values as part of their basis for establishing fish consumption advisories. These numbers range from 0.1 

ppm for Connecticut to 1.0 ppm for New York State. Different issues are weighed when establishing fish 

consumption advisories than those considered in setting a regional TMDL. For example, eating fish has 

health benefits and those benefits are weighed against the health risks posed by mercury contamination. 

The risks from contamination for children and women of childbearing age differ from those posed to men 

and older women and the health benefits of eating fish may also differ for these age groups. In 

developing a TMDL, the issue being considered is minimizing contamination in fish as the benefit, and 

the costs of preventing the contamination as the risk. Based on these considerations for the regional 

TMDL, 0.3 ppm is used as the initial overall regional target fish mercury concentration to be consistent 

with EPA’s methylmercury fish tissue criterion and meet fish tissue goals in Massachusetts, New 

Hampshire, New York, Rhode Island, and Vermont. It should be noted that the goal of this TMDL is to 

use adaptive implementation to achieve a target of 0.3 ppm for Massachusetts, New Hampshire, New 

York, Rhode Island, and Vermont; 0.2 ppm for Maine, and 0.1 ppm for Connecticut. Such an approach 

will allow all of the Northeast states to meet or exceed their designated uses. 

Figure 5-2 shows the cumulative distribution of length-standardized smallmouth bass mercury 

concentrations based on data within the NERC dataset, in comparison to those for all fish species. The 

80th percentile value of 0.86 ppm mercury for smallmouth bass corresponds to the 90th percentile 

concentration for all fish species, whereas the 90th percentile value of 1.14 ppm mercury for smallmouth 

bass corresponds to the 96th percentile concentration for all fish species. As such, by targeting the 90th

percentile range of smallmouth bass concentrations, 96 percent of fish should ultimately meet the fish 

tissue target. 

Implementation of this TMDL will serve as a first step toward eliminating fish consumption advisories in 

the Northeast states. For purposes of demonstrating compliance with individual states’ water quality 

standards, it is noted that to meet water quality standards in both Maine and Connecticut, calculations 

require reductions in anthropogenic mercury deposition greater than 100 percent. The calculation of 

needed reductions is affected by a number of variables, including the percentage of deposition due to 

anthropogenic sources, and there are a range of accepted values associated with this parameter. Various 

studies have found this percentage to be between 75 and 85 percent. Use of a lower percentage results in 

a greater percent reduction from anthropogenic sources, whereas a higher percentage has the opposite 

effect. Because of these ranges and other reasonable and prudent assumptions made about values for a 

number of parameters, adaptive management will be used when implementing the reductions necessary to 

meet the TMDL. Throughout the final stage of implementation, the states will re-evaluate progress made 

toward the fish tissue goals and will determine if adjustments need to be made in the ultimate goals that 

have been set, or how they can be achieved in accordance with the timeline set forth in the 

implementation plan. 
Northeast Regional Mercury TMDL – October 2007 16 

Figure 5-2: Cumulative Distribution of Mercury Concentrations (ppm) in Northeast Fish 

Total mercury in fillets (ppm wet weight)

0.1 1

Cumulative % of observations

0

20

40

60

80

100

All species 80th %ile = 0.68, 90th %ile = 0.91

Smallmouth bass 80th %ile = 0.86, 90th %ile = 1.12 

5.5 Proportionality of Mercury Reductions 

At this time, there is no precise modeling (at least not at a large spatial scale involving multiple 

waterbodies) of the link between emissions and mercury bioaccumulation or the effect of a given 

emissions reduction on fish tissue concentrations. While study results are converging on an 

understanding of likely reductions in fish tissue mercury given reductions in proximal mercury emissions 

sources, the state of science is not yet such that this relationship can be described with confidence. 

Therefore it is reasonable to rely on certain assumptions regarding the relationships between mercury 

emissions, deposition, and fish tissue concentrations. There is sufficient empirical evidence to show that 

emissions reductions cause reductions in fish tissue concentrations, which validates the assumptions used 

in this TMDL. 

The TMDL is based on an assumption that a decrease in mercury emissions will result in a proportional 

decrease in mercury deposition, a decrease in mercury deposition will result in a proportional decrease in 

mercury loading to waterbodies, and ultimately, a decrease in mercury loading in waterbodies will result 

in a proportional decrease in mercury concentrations in fish. This follows the analyses presented by the 

EPA Mercury Maps Model, which is based on steady state formulations of the Mercury Cycling Model 

(MCM) and IEM-2M Model (U.S. EPA 2001). In environmental systems, steady state means that 

concentrations may vary from season to season or year to year, but that long term averages are constant. 

Several dynamic, ecosystem scale models such as the Mercury Cycling Model (MCM) and IEM-2M 

assume that, at steady state (i.e., over long time scales), reductions in fish mercury concentrations will be 

proportional to reductions in mercury inputs. When atmospheric deposition is the main source of mercury 

to a given waterbody, these models predict a linear response between changes in deposition, ambient 

concentrations in water and sediments, and fish mercury levels. Below, an approach is outlined for 
Northeast Regional Mercury TMDL – October 2007 17 

deriving a simplified relationship between percent reductions in air deposition load and fish tissue 

concentrations at steady state that draws on this same assumption of long-term proportionality from more 

complex modeling frameworks. 

The standard steady state bioaccumulation equation is: 

C Cwater

BAF fish t t1 1

= •

where Cfisht1 and Cwatert1 are methylmercury contaminant levels in fish and water at time t1, respectively 

and BAF is the site specific bioaccumulation factor, which is constant for a given age/length and species 

of fish in a specific waterbody. 

For a future time, t2, when mercury concentrations have changed but all other parameters remain 

constant, the equation can be written as: 

C Cwater

BAF fish t t 2 2

= •

where Cfisht2 and Cwatert2 are methylmercury contaminant levels in fish and water at time t2, respectively 

and Cfisht2 is for a fish that is the same age, length, and species as for Cfisht1. 

Combining the equations produces: 

C

C

C

C

water

water

fish

fish

t

t

t

t

2

1

2

1 =

Because methylmercury water column concentrations are proportional to mercury air deposition load to a 

watershed, this equation can be rewritten as: 

L

L

C

C

air

air

fish

fish

t

t

t

t

2

1

2

1 =

where L airt1 and Lairt2 are the air deposition mercury loads to a waterbody at time t1 and t2, respectively. 

It is reasonable to predict that, based on this relationship, mercury fish concentrations will likely be 

reduced from current levels in proportion to load reductions for the watershed. For waterbodies in which 

air deposition is the only significant source, fish tissue mercury concentration reductions will likely be 

directly proportional to air deposition reductions over the long term. 

Because these relationships are based on steady states, we do not expect that a proportional relationship 

between atmospheric deposition reductions and fish tissue reductions will be observed immediately. 

However, it is expected this response will be seen over the long term, once systems have reached steady 

state. While it is acknowledged that there is a time lag between mercury being deposited on land and that 

mercury reaching waterbodies, it is assumed that the terrestrial system will eventually reach a new steady 

state with atmospheric deposition, and total loading of mercury to surface water will be proportional to 

atmospheric deposition. 
Northeast Regional Mercury TMDL – October 2007 18 

The effects of the approach have been evaluated by Kamman, et al. (2006) for the region. The rate of 

change in fish mercury will vary among Northeast waterbodies due to different conditions that affect the 

production of methylmercury and bioaccumulation of methylmercury. These factors include watershed 

area, productivity, acidification status, sulfate loading, and water-level manipulation. However, empirical 

evidence is mounting that biological mercury concentrations are reduced in proportion to emissions and 

resultant deposition reductions (Evers, et al. 2006 and Florida Department of Environmental Protection 

2003).

6 Source Assessment

6.1 Northeast States Emissions Inventory 

In 1998, NESCAUM prepared Atmospheric Mercury Emissions in the Northeastern States to refine the 

emissions inventory figures developed by EPA for the Northeast region in conducting their national 

evaluation of atmospheric mercury emissions in accordance with the requirements of the 1990 Clean Air 

Amendments. Refinements were made based on facility-specific information collected by state air quality 

agencies, including stack test data, fuel use rates, air pollution control devices, and other operational 

parameters (NESCAUM 2005). The inventory quantifies mercury emissions representative of the year 

1998 for combustion, manufacturing, and area sources in New England, New York State, and New Jersey. 

The study was a combined effort of the state and provincial air, waste, and water management agencies in 

the Northeast states and eastern Canadian provinces and was intended to serve as an information resource 

to these agencies and as a foundation for future regional initiatives, including the development of a 

coordinated action plan to reduce the environmental and public health impacts of mercury (NESCAUM 

1998). 

The inventory is divided into direct and area sources. Direct sources, which include combustion and 

manufacturing sources, typically release emissions from a stack and are large enough to be associated 

with a specific geographic location. Area sources are typically small, but there may be a large number of 

them, and they are not usually associated with emissions from a stack. Area sources include categories 

such as fossil fuel residential heating, fluorescent lamp breakage and recycling, laboratory use, dental use, 

and crematories. As seen in Figure 6-1, approximately 87 percent of the mercury emissions inventory in 

the Northeast states can be attributed to direct sources. About 9 percent of the direct emissions are due to 

manufacturing sources, with the remainder being attributed to the various combustion sources. The 

largest combustion sources were municipal waste combustors (MWCs) at 56 percent and electric utility 

boilers at 12 percent (NESCAUM 1998). Table 6-1 provides a full summary of emissions by category. 

NESCAUM’s regional inventory included New Jersey, but emissions data reported here include only 

New England and New York State. The emissions sources for the region can be compared to the major 

sources of national mercury emissions in a similar time period, as seen in Figure 6-2. 
Northeast Regional Mercury TMDL – October 2007 19 

Figure 6-1 Breakdown of Major Sources of Northeast Regional Mercury Emissions in 1998 

(NESCAUM 1998) 

Manufacturing

9% MWIs

6%

SSIs

5%

Electric

Utility Boilers

7%

MWCs

55%

Area Sources

13%

Direct Sources

87%

Commercial/

Industrial Boilers

4%
Northeast Regional Mercury TMDL – October 2007 20 

Figure 6-2 Major Sources of National Mercury Emissions in 1996 (Driscoll, et al. 2007) 

Industrial/Commercial/ 

Industrial Boilers

8%

Chlorine Production

5%

Hazardous Waste 

Incineration

3%

Municipal Waste

Combustors

22%

Medical Waste

Incinerators

27%

Coal-fired

Power Plants

35%
Northeast Regional Mercury TMDL – October 2007 21 

Table 6-1 1998 Northeast1

 Regional Mercury Emissions Inventory 

Mercury Source Categories Emissions Estimate 

(kg/yr) 

Percent of Inventory 

Direct Sources 

Combustion Sources 

Municipal Waste Combustors 6,896 55.2 

Sewage Sludge Incinerators 657 5.3 

Medical Waste Incinerators 758 6.1 

Commercial/Industrial Boilers Total 552 4.4 

Fossil Fuel-Fired 449 3.6 

Wood-Fired 103 0.8 

Electric Utility Boilers Total 864 6.9 

Coal-Fired 697 5.6 

Oil-Fired 142 1.1 

Natural Gas-Fired 18 0.1 

Wood-Fired 7 0.1 

Total Combustion Sources 9,727 77.9 

Manufacturing Sources 

Secondary Mercury Production 319 2.6 

Cement Manufacturing 305 2.4 

Lime Manufacturing 15 0.1 

Steel Foundries 17 0.1 

Chlor-Alkali Facilities 460 3.7 

Misc. Industrial Processes 3 0.02 

Total Manufacturing Sources 1,119 9.0 

Total Direct Sources 10,846 86.8 

Area Sources 

Residential Heating 575 4.6 

Industrial Processes 1,073 8.6 

Electric Lamp Breakage & 

Recycling 

379 3.0 

General Lab Use 48 0.4 

Dental Preparation and Use 70 0.6 

Crematories 70 0.6 

Latex Paint 506 4.0 

Total Area Sources 1,648 13.2 

Total Emissions 12,494 100 

 

1

 NESCAUM’s original Northeast inventory included New Jersey, but data presented here are for New England and 

New York State only. 
Northeast Regional Mercury TMDL – October 2007 22 

6.2 Atmospheric Deposition Modeling 

NESCAUM has performed atmospheric deposition modeling using the Regional Modeling System for 

Aerosols and Deposition (REMSAD). This is a Eulerian grid model that includes atmospheric transport 

and chemistry. The REMSAD model uses tagging, which allows tracking of emissions through space and 

time. Tags can be individual sources, source types, and source regions (Graham, et al. 2006). 

NESCAUM conducted two modeling runs, one using 1998 emissions inventory for the Northeast region 

and one using 2002 emissions inventory for the Northeast region. Both modeling runs used 1996 

meteorology data and 1999 or 2001 out-of-region emissions data depending on the source type (e.g. area 

sources vs. electric-generating units). Boundary conditions were obtained from the global mercury model 

GEOS-CHEM. The Northeast region, as defined by NESCAUM, includes the New England states, New 

York State, and New Jersey, whereas this TMDL defines the Northeast region as the New England states 

and New York State. Consequently, NESCAUM’s modeling separated contributions from New England 

and New York State/New Jersey as one unit, but did not separate the contributions of New York State and 

New Jersey. NESCAUM was able to provide estimates of the separate contributions of New York State 

and New Jersey by splitting each of the contributing source categories based on location and amount of 

emissions, and then apportioned the deposition from the model runs accordingly (John Graham, electronic 

mail, December 19, 2006). The model results shown below for U.S. sources account only for 

anthropogenic sources of mercury and do not include atmospheric deposition of mercury from natural 

sources. Results for global sources include a natural component, which is further discussed below. 

Table 6-2 Modeled Mercury Atmospheric Deposition (kg/yr) in 1998 and 2002 for the Northeast1

Region 

Source Northeast 

States 

Rest of the 

U.S. 

Global 

Sources2 

Total 

1998 Modeled Total Deposition 2,092 1,207 2,106 5,405 

1998 Modeled Natural Deposition 0 0 527 527 

1998 Modeled Anthropogenic Deposition 2,092 1,207 1,580 4,879 

2002 Modeled Total Deposition 543 791 2,106 3,440 

2002 Modeled Natural Deposition 0 0 527 527 

2002 Modeled Anthropogenic Deposition 543 791 1,580 2,914 

1

Northeast region includes the New England states and New York State. 

2

Global sources include recirculating historical emissions from the U.S. 

The global source estimate includes approximately 253 kg/yr (2,106 kg/yr x 0.12) attributable to primary 

natural sources. This value is based on the global modeling that the boundary conditions were derived 

from, where approximately 12 percent of the inventory was from primary natural emissions. The global 

source contribution also includes recirculating natural source emissions from the U.S. Based on the 

assumption used in this TMDL that deposition is 75 percent anthropogenic and 25 percent natural 

(Kamman and Engstrom 2002, further discussed in Section 7.2), the contribution of recirculating natural 

source emissions is set at 13 percent, so that the contributions of primary natural emissions and 

recirculating natural source emissions sum to 25 percent. Based on this assumption, recirculating natural 

source emissions are equal to 274 kg/yr (2,106 kg/yr x 0.13). No other natural sources were accounted 

for in the regional deposition modeling. When global natural sources are subtracted from the total 

deposition results, the total anthropogenic deposition is 4,879 kg/yr for 1998 and 2,914 kg/yr for 2002. In 

order to avoid double counting of natural mercury deposition, modeled natural deposition was excluded 

from TMDL calculations. Modeled anthropogenic deposition was used as a base from which to estimate 

total regional natural mercury deposition based on regional studies that estimate regional deposition is 25 

percent natural and 75 percent anthropogenic (Kamman and Engstrom 2002). This is further discussed in 

Section 7.2. 
Northeast Regional Mercury TMDL – October 2007 23 

Figure 6-3 shows maps of the regional modeled mercury deposition for 1998 and 2002. Although 

deposition is not uniform across the region, because elevated mercury levels are a problem across the 

region, the states emphasize that the regional approach is appropriate as discussed in detail in Section 5. 
Northeast Regional Mercury TMDL – October 2007 24 

Figure 6-3 Total Regional Modeled Mercury Deposition in 1998 and 2002 based on REMSAD 

Modeling 

1998 Modeled Mercury Deposition 

2002 Modeled Mercury Deposition 

Mercury Deposition 

(μg/m2

)

Mercury Deposition 

(μg/m2

)
Northeast Regional Mercury TMDL – October 2007 25 

6.3 Point Sources to Water 

There are 3,119 National Pollutant Discharge Elimination System (NPDES) permitted facilities 

discharging to the waters of New England and New York State. These include publicly owned treatment 

works (POTWs), as well as industries such as pulp and paper mills, chlor-alkali plants, and manufacturers 

of lighting equipment, chemicals, and metals. 

To estimate the point source mercury load for the region, mercury monitoring data and design flow data 

were used. All available point source mercury monitoring data from 1988 to 2005 were obtained from the 

participating states. With one exception, only data that were collected using EPA Method 1631 were 

included in the analysis. Rhode Island had a small amount of data that were collected under EPA Method 

245.1, but were determined to be acceptable for inclusion in this dataset. The treatment plants were able 

to achieve a method detection limit that was much lower than what is normally achieved with this method 

and the mean concentrations for the two facilities fell into the range of the other facilities in the dataset. 

 

For any facility with multiple measurements, all data points were averaged to calculate a mean mercury 

concentration for each facility. These mean values were all combined into one dataset and the median 

mercury concentration for the region was calculated. This value, 7.7 ng/l, was used as a typical point 

source mercury concentration for the region. Facilities discharging to coastal waters were excluded from 

design flow calculations, but concentration data from coastal facilities were retained because the amount 

of available mercury effluent data is small and there is no reason to believe that mercury effluent 

concentrations would differ between facilities discharging to marine and fresh waters. Because regional 

mercury loading from wastewater sources is a very small amount compared to the total mercury loading 

to the region, combining all mercury point sources into one regional median is an appropriate approach. 

Design flow data for all NPDES permitted facilities in the region were obtained from EPA Region 1, New 

York State Department of Environmental Conservation (NYS DEC), and Vermont Department of 

Environmental Conservation (VT DEC). Facilities that primarily discharge cooling water were not 

included in point source mercury load estimates because their discharges do not contain appreciable 

amounts of mercury. Facilities that discharge to marine waters were also excluded because this TMDL 

targets only freshwaters. A median value was calculated from the available data and used as an estimate 

for any facilities for which design flow data were not available. The known and estimated design flows 

for all regional facilities were then summed together. This value was used with the regional point source 

concentration estimate of 7.7 ng/l to estimate the total point source load. The breakdown of effluent 

concentrations and design flows by state is shown below in Table 6-3. The mean mercury effluent 

concentrations used in calculating the regional median concentration are shown in Appendix C. 
Northeast Regional Mercury TMDL – October 2007 26 

Table 6-3 Mercury Point Sources to Water 

State 

Number of 

Facilities w/ 

Data 

Mean 

Concentration 

(ng/l) 

Median 

Concentration 

(ng/l) 

Sum of 

Design 

Flows 

(MGD) 

CT 0 12.1 7.7 7,105

ME 182 17.3 7.3 515

MA 5 22.9 7.7 1,791

NH 0 12.1 7.7 138

NY 50 17.8 9.8 3,622

RI 2 17.0 17.0 56

VT 10 1.3 1.3 95

Northeast 

Region 249 12.1 7.7 13,322

*Because no effluent data were available for New Hampshire, and Connecticut only had data collected 

under EPA Method 245.1, the regional median and means are used as estimates for these states. 

7 Development of a Regional Total Maximum Daily Load 

7.1 TMDL Formulation 

The TMDL formulation used for this regional mercury TMDL is similar to the Minnesota Statewide 

Mercury TMDL, approved by EPA March 27, 2007, which employs a total source load (TSL) and 

reduction factor (RF) to define the desired TMDL. In general, the three-step process to determine a 

TMDL is to (1) determine the existing load for point and nonpoint sources; (2) define the target loads; and 

(3) calculate load reduction factors necessary to achieve the target values. The total source load (TSL) 

and reduction factor (RF) are then combined to give the TMDL for the area of concern as shown in 

Equation 1. 

Equation 1: TMDL = TSL· (1-RF) 

where: TMDL is the total maximum daily load (kg/yr) that is expected to result in 

attainment of the target fish mercury concentration specified in Section 5.3 

 TSL is the existing total source load (kg/yr), and is equal to the sum of the 

existing point source load (PSL) and the existing nonpoint source load (NPSL) 

and 

RF is the reduction factor required to achieve the target fish mercury 

concentration (see Section 7.3 for calculations) 

Once the TMDL is calculated in accordance with Equation 1, the allowable load can then be allocated 

among the point sources, nonpoint sources and an explicit MOS (if necessary) in accordance with the 

conventional TMDL formula shown as Equation 2 below. 

Equation 2: TMDL = WLA + LA + MOS 

where: WLA = Wasteload Allocation or point sources 
Northeast Regional Mercury TMDL – October 2007 27 

 LA = Load Allocation or nonpoint sources 

 MOS = Margin of Safety 

Each of the terms used in Equations 1 and 2 are further discussed in Sections 7.2 through 7.7 followed by 

a presentation of the final TMDL in Section 8. 

7.2 Calculation of Existing Total Source Load (TSL) 

Calculation of the existing Total Source Load (TSL) of mercury, in kg/yr, is presented below in Equation 

3 and is the sum of the existing point source and nonpoint source loadings. 

Equation 3: TSL = PSL + NPSL 

The calculation for the PSL is presented below in Equation 4 and is estimated for the region based on the 

total design flow of wastewater treatment facilities and the median effluent mercury concentration. The 

PSL is the product of the regional median mercury concentration in effluent and the sum of design flows 

for each permitted facility in the region. 

Equation 4: PSL = Cmed · ∑ Qi 

where: Cmed = Median mercury concentration in effluent of NPDES permitted discharges 

 Qi = Design flow of each NPDES permitted discharge (excluding cooling water 

 and marine discharges) 

Cmed is derived from all appropriate available point source mercury monitoring data obtained from the 

participating states, and is equal to 7.7 ng/l (see Table 6-3). The sum of regional design flows, excluding 

facilities that primarily discharge cooling water or discharge to coastal waters, is 13,322 MGD (see Table 

6-3). Based on Equation 4 and the data presented in Table 6-3, the existing PSL is 141 kg/yr. 

It should be noted that the calculated point source load is considered to be overestimated. Many of the 

waterbodies that are covered by this TMDL do not have any point source discharges and therefore are not 

affected by the regional point source load. In addition, actual flows are considerably lower than design 

flows, so use of design flows in the calculation inflates the point source load. 

When stormwater is addressed in a TMDL, it is generally included with the point source load and 

subsequently included in the wasteload allocation. However, most mercury in stormwater comes from 

atmospheric deposition. In this TMDL, regulated stormwater is included in the WLA and unregulated 

stormwater is included in the LA. Because the majority of mercury in stormwater originates from 

atmospheric deposition, reductions of mercury loading in stormwater will be addressed through controls 

on atmospheric deposition. 

The nonpoint source load (NPSL) calculation, as presented below in Equation 5, reflects the contributions 

of natural (NNPSL) and anthropogenic (ANPSL) sources of mercury deposition. 

Equation 5: NPSL = NNPSL + ANPSL

The only significant nonpoint source can be attributed to atmospheric deposition. Other contributions, 

such as land application of municipal sewage sludge, are assumed to be insignificant. As discussed in 
Northeast Regional Mercury TMDL – October 2007 28 

Section 6.2, the modeled anthropogenic atmospheric mercury deposition (ANPSL) for 1998 is 4,879 

kg/yr. 

Based on results of several paleolimnological studies in the Northeast, background or natural mercury 

deposition estimates range from 15 percent to 25 percent of circa year 2000 deposition fluxes (Perry, et 

al., 2005, Norton, et al. 2004, Seigneur, et al. 2003, Kamman and Engstrom 2002, Lorey and Driscoll 

1998, and Norton, et al. 1997). These values are consistent with other published values from the upper 

Midwest and elsewhere. For the purposes of this TMDL, the paleolimnological studies are used to 

conclude that the proportion of deposition due to natural sources (PDNS) in the Northeast is 25 percent of 

the total deposition load. Natural sources cannot be controlled and are expected to remain at the same 

long-term average; therefore all mercury reductions must come from anthropogenic sources. The NPSL 

and NNPSL can be calculated from Equations 6 and 7 below. 

Equation 6: NPSL = ANPSL / (1-PDNS) 

Equation 7: NNPSL = NPSL · PDNS 

Based on these equations, an ANPSL of 4,879 kg/yr, and a PDNS of 0.25, NPSL is equal to 6,506 kg/yr 

and NNPSL is equal to 1,626 kg/yr. Knowing the PSL and NPSL, the 1998 TSL can be calculated in 

accordance with Equation 3 as shown below: 

1998 TSL = 141 kg/yr + 6,506 kg/yr = 6,647 kg/yr 

 

Based on these values, existing point source loads represent 2.1 percent and existing nonpoint source 

loads represent 97.9 percent of the 1998 TSL. 

7.3 Reduction Factor (RF)

The calculation for the RF is presented below in Equation 8 and is based on the reductions required to 

achieve the target fish mercury concentrations. 

Equation 8: RF = (EFMC – TFMC)/ EFMC 

where: EFMC = the existing fish mercury concentration for the selected fish species 

TFMC = the target fish mercury concentration for meeting water quality 

standards 

As discussed in Section 5.2, the EFMC for this study is 1.14 ppm which represents the 90th percentile 

concentration based on standardized length for smallmouth bass. As discussed in Section 5.3, the initial 

TFMC is equal to 0.3 ppm, with subsequent TFMCs of 0.2 ppm and 0.1 ppm. Inserting these values into 

Equation 8 results in the RFs shown in the table below1

. 

 

1

 As was noted previously, all TMDL calculations are shown for the range of 80th to 90th percentile fish tissue 

concentrations to address uncertainty. For purposes of TMDL implementation, the target is the 90th percentile fish 

tissue concentration. 
Northeast Regional Mercury TMDL – October 2007 29 

TFMC (ppm) RF 80th percentile RF 90th percentile 

0.3 0.65 0.74 

0.2 0.77 0.82 

0.1 0.88 0.91 

7.4 TMDL Calculation 

As previously mentioned, the TSL is equal to 6,651 kg/yr (see Section 7.3). Inserting the TSL and the 

RFs calculated in Section 7.3 into Equation 1 yields the TMDLs shown in the table below. This is the 

total allowable loading of mercury that, over time, is expected to result in meeting the target mercury fish 

concentrations. 

TFMC (ppm) TMDL 80th Percentile (kg/yr) TMDL 90th percentile (kg/yr) 

0.3 2,320 1,750 

0.2 1,547 1,167 

0.1 773 583 

7.5 Wasteload Allocation (WLA) 

According to Equation 2, the calculated permissible load (TMDL) of mercury that will not cause the 

applicable water quality standards to be exceeded is the sum of the wasteload allocation (point sources), 

load allocation (nonpoint sources), and an explicit MOS, if applicable. As explained in Section 7.7, an 

implicit MOS is used for this study which infers an explicit MOS of zero. Therefore the TMDL is equal 

to the sum of the WLA and LA. As discussed in Section 7.2, point sources primarily consist of 

discharges from NPDES wastewater treatment facilities and the only significant nonpoint source is 

atmospheric deposition. Consequently, the total load is apportioned between wastewater and atmospheric 

loads. 

The WLA includes the contributions from regulated stormwater sources, which includes mercury 

primarily from atmospheric sources as small contributions from local sources within the watershed and 

natural sources. Although the contribution of stormwater to mercury loading is unknown, the vast 

majority of mercury from stormwater that contributes to the impairment of these waters originates from 

air sources and should be controlled accordingly. Regulated stormwater is considered to be part of the de 

minimis WLA, and will be addressed through the controls on atmospheric deposition sources that are 

required to meet the load allocation. The states anticipate that once atmospheric deposition reductions are 

met, the only remaining regulated stormwater contributions would be solely attributed to natural sources 

and run-off from localized non-atmospheric sources. Given the states’ commitment to virtual elimination 

of mercury, this residual stormwater contribution is considered to be a minute part of the WLA. 

The states are already engaged in controlling stormwater pollution using best management practices 

(BMPs) in accordance with Clean Water Act §402(p) and 40 CFR 122.44(k) and any residual mercury in 

stormwater that originates from non-atmospheric sources can be addressed by these programs. The six 

minimum measures associated with permits for municipal separate storm sewer systems (MS4s) will 

contribute toward reducing mercury loading by reducing stormwater volume and sediment loading. 

As discussed in Section 7.2, the existing point source load for the entire region is 2.1 percent of the TSL 

for mercury, which is small (as compared to the LA) and expected to further decline based on enacted 

mercury products legislation and increasing required use of dental amalgam separators throughout the 
Northeast Regional Mercury TMDL – October 2007 30 

region. According to EPA’s Draft Guidance for Implementing the January 2001 Methylmercury Water 

Quality Criterion, point source discharges are considered insignificant if the loading or cumulative 

loading of all point sources to the receiving water are expected to account for a small or negligible portion 

of the total mercury loadings (U.S. EPA 2006a). All significant decreases in mercury loading to the 

region will come from reductions in atmospheric deposition (i.e., load allocation). 

This TMDL places much emphasis on the fact that the states have agreed to a goal of virtual elimination 

of mercury. As is stated in Section 2.5 of the TMDL, as of 2006, all of the Northeast states have passed 

legislation to address mercury in products and require installation of dental amalgam separators. 

Individual laws and requirements vary by state, but legislation addresses bans on disposal of mercuryadded products, bans on sale or distribution of mercury-added novelties and measuring devices, 

requirements for labeling of mercury-added products, prohibition of primary and secondary schools 

purchasing or using mercury, removal of mercury switches from automobiles, and requirements on 

recycling of mercury-added products. The end result of all these mercury reduction efforts is that a 

smaller quantity of mercury makes its way into the waste stream and less mercury is discharged from 

wastewater treatment facilities. These efforts undoubtedly increase the likelihood of successfully 

implementing the WLA. Because these reduction efforts are ongoing, the states feel there is little else 

that could be done through the NPDES program that could further ensure that the WLA will not be 

exceeded. However, states will conduct investigations, as appropriate, on a permit by permit basis, to 

prevent localized exceedances of the WLA . As a result, the WLA is set at 2.1 percent of the TMDL, 

which is equivalent to the values shown in the table below. 

TFMC (ppm) WLA 80th percentile (kg/yr) WLA 90th percentile (kg/yr) 

0.3 49 37 

0.2 33 25 

0.1 16 12 

The WLA in this TMDL is regional and is not specific to each particular state or source. Instead of 

allocating the WLA among sources, mercury reduction will be accomplished through mercury 

minimization plans (MMPs) and the continuation of region-wide mercury reduction efforts as described 

above. MMPs help ensure that discharges have no reasonable potential to cause or contribute to an 

exceedance of water quality standards. EPA believes that a requirement to develop a MMP may provide 

dischargers with sufficient information to voluntarily and economically reduce mercury discharges (EPA 

2006a). Evaluation of progress at the Phase II milestone will determine if mercury minimization plans 

and additional monitoring at point sources should be prescribed for dischargers that do not already have 

those programs in place. All new or increased discharges will be required to stay below the regional 

WLA. 

7.6 Load Allocations 

7.6.1 Load Allocation Calculations 

Subtracting the WLAs calculated in Section 7.5 from the TMDLs calculated in Section 7.4 in accordance 

with Equation 2, and assuming an explicit MOS of zero for reasons discussed in Section 7.7, yields the 

regional mercury LAs shown in the table below. 
Northeast Regional Mercury TMDL – October 2007 31 

TFMC (ppm) LA 80th percentile (kg/yr) LA 90th percentile (kg/yr) 

0.3 2,269 1,712 

0.2 1,513 1,141 

0.1 756 571 

However, as discussed in Section 7.2, 1,626 kg of the TSL is due to natural sources of mercury and 

cannot be controlled (this number represents the natural load allocation or NLA). The anthropogenic load 

allocation (ALA) can be calculated using Equation 9 below. 

Equation 9: ALA = LA – NLA 

Using this equation with the LAs shown above and NLA of 1,626 yields the ALAs shown in the table 

below. This represents the range of anthropogenic atmospheric deposition goals for the Northeast states, 

to be achieved through reductions in both in-region and out-of-region sources. 

TFMC (ppm) ALA 80th percentile (kg/yr) ALA 90th percentile (kg/yr) 

0.3 643 86 

0.2 -1131 -485 

0.1 -870 -1,056 

7.6.2 Necessary Reductions to Meet LA

In order to meet the ALA, the necessary reductions in anthropogenic atmospheric deposition can be 

calculated through equation 10 below: 

Equation 10: Percent reduction in anthropogenic deposition = [100 · (ANPSL – ALA)/ANPSL] 

Using this equation, the necessary reductions are shown in the table below. 

TFMC (ppm) Necessary Percent Reduction in 

Anthropogenic Deposition 80th

percentile 

Necessary Percent Reduction in 

Anthropogenic Deposition 90th

percentile 

0.3 87% 98% 

0.2 102% 110% 

0.1 118% 122% 

Necessary reductions to meet the LA are divided into in-region and out-of-region contributions. 

Reductions are divided into three phases, Phase I from 1998 to 2003, Phase II from 2003 to 2010, and 

Phase III beginning in 2010 with an end date to be determined in 2010. The timeline and goals for Phases 

 

1 It is noted that to meet water quality standards in both Maine and Connecticut, calculations require reductions in 

anthropogenic mercury deposition greater than 100 percent, resulting in negative anthropogenic load allocations. 

However, these calculations are affected by a number of variables including the percentage of deposition due to 

anthropogenic sources, and there is a range of accepted values associated with this number. Various studies have 

found this percentage to be between 75 and 85 percent. Use of a lower percentage results in a greater percent 

reduction from anthropogenic sources, whereas a higher percentage has the opposite effect. Because of this 

uncertainty, adaptive management will be used when implementing the reductions necessary to meet the TMDL. 

Throughout Phase III, the states will re-evaluate progress made towards the 0.2 and 0.1 goals and will determine if 

adjustments need to be made in the ultimate goals that have been set, or how they can be achieved in accordance 

with the timeline set forth in the implementation plan. 
Northeast Regional Mercury TMDL – October 2007 32 

I and II are set to correspond with the NEG-ECP regional MAP. In 2010, mercury emissions, deposition, 

and fish tissue concentration data will be re-evaluated with current information. This information will be 

used to set an end date and reduction goal for Phase III, which will represent completion of necessary

reductions to meet water quality standards. Based on updated data, the final TMDL goal may differ from 

the percents reduction presented in this document. If this occurs, the TMDL goals will be revised and 

updated. 

Based on the calculated percents reduction in anthropogenic sources, necessary mercury reductions 

amount to values shown in the table below. 

TFMC (ppm) Necessary Reductions in 

Anthropogenic Deposition 

80th percentile (kg/yr) 

Necessary Reductions in 

Anthropogenic Deposition 

90th percentile (kg/yr) 

0.3 4,236 4,793 

0.2 4,993 5,364 

0.1 5,749 5,935 

Based on the amount of atmospheric deposition attributed to in-region and out-of-region sources by 

NESCAUM’s modeling, the necessary reductions can be divided between in-region and out-of-region 

sources. These reductions are shown in the tables below. 

TFMC (ppm) Necessary In-Region Reductions in 

Anthropogenic Deposition 80th

percentile (kg/yr) 

Necessary In- Region Reductions in 

Anthropogenic Deposition 90th

percentile (kg/yr) 

0.3 1,816 2,055 

0.2 2,141 2,300 

0.1 2,465 2,545 

TFMC (ppm) Necessary Out-of Region Reductions in 

Anthropogenic Deposition 80th

percentile (kg/yr) 

Necessary Out-of-Region Reductions 

in Anthropogenic Deposition 90th

percentile (kg/yr) 

0.3 2,420 2,738 

0.2 2,852 3,064 

0.1 3,284 3,390 

The goal for Phase I (1998-2003) is a 50 percent reduction, or 1,046 kg/yr from in-region sources and 

1,394 kg/yr from out-of-region sources. As of 2002, in-region sources had been reduced by 1,549 kg/yr, 

so the in-region goal for Phase I was exceeded. Not enough data are currently available to accurately 

assess reductions achieved by out-of-region sources. The goal for Phase II (2003-2010) is a 75 percent 

reduction, or 1,569 kg/yr from in-region sources and 2,090 kg/yr from out-of-region sources. Based on 

in-region reductions achieved as of 2002, in-region reductions of 20 kg/yr are necessary to meet the Phase 

II goal. 

Once Phase II goals are successfully met, in-region and out-of-region sources will need to be reduced by 

the amounts shown in the table below. However, as discussed above, mercury emissions, deposition, and 

fish concentration data will be re-evaluated at the completion of Phase II in 2010. If necessary, 

reductions for meeting the target fish concentration will be revised based on updated data. As further 

discussed in Section 9, TMDL goals will be implemented in an adaptive fashion. 
Northeast Regional Mercury TMDL – October 2007 33 

TFMC (ppm) Remaining In-Region Reductions 

after Phase II 80th Percentile (kg/yr) 

Remaining In-Region Reductions 

after Phase II 90th Percentile (kg/yr) 

0.3 247 486 

0.2 572 731 

0.1 896 976 

TFMC (ppm) Remaining Out-of-Region 

Reductions after Phase II 80th

Percentile (kg/yr) 

Remaining Out-of-Region 

Reductions after Phase II 90th

Percentile (kg/yr) 

0.3 330 648 

0.2 762 974 

0.1 1,194 1,300 

The Northeast region’s ability to achieve the calculated TMDL allocations is dependent on the adoption 

and effective implementation of national and international programs to achieve necessary reductions in 

mercury emissions. Given the magnitude of the reductions required to implement the TMDL, the 

Northeast cannot reduce in-region sources further to compensate for insufficient reductions from out-ofregion sources. This is further discussed in detail in Section 10. 

7.7 Margin of Safety

Regulations require that a MOS is included in a TMDL to account for uncertainty that may be present in 

the calculations. A MOS can either be explicit (e.g., additional percentage load reduction), implicit in the 

calculations, or a combination of the two. For this mercury TMDL, the MOS is implicit because of the 

following conservative assumptions used to develop this TMDL: 

 The 90th percentile fish mercury concentration based on a standard length smallmouth bass was 

used. Smallmouth bass has the highest concentrations of the four species selected for calculation 

(see Table 4-2). The vast majority of fish have concentrations lower than this. According to 

Equation 1, the higher the EFMC, the higher the RF and the lower the TMDL. As many people 

eat a combination of fish, some at lower trophic levels than smallmouth bass, use of the 90th

percentile smallmouth bass incorporates a margin of safety into the analysis. 

 Atmospheric sources of mercury in the Northeast are categorized as 25 percent natural (Kamman 

and Engstrom 2002), but could range from 15 to 25 percent, based on a number of regional 

studies. Given the Northeast region’s location downwind of mercury sources and the fact that 

available sediment cores are largely from more rural sites less impacted by direct air emissions 

sources, the percentage of baseline deposition attributable to natural sources across the region is 

likely lower than the 25 percent used in this analysis. Use of a lower value, such as 15 percent, 

would have resulted in lower required reductions in anthropogenic sources. 

 The transformation of mercury to methylmercury is dependent on sulfur, so it is believed that 

reductions in sulfur deposition will lead to reduced methylation of mercury. As ongoing federal 

and state programs are reducing sulfur emissions and deposition, methylation of mercury should 

also decrease. As the TMDL does not account for this potential reduction in mercury 

bioaccumulation, proposed mercury reductions based on the TMDL may be overestimated and 

therefore provide an extra level of protection. 

 The EPA fish tissue criterion and state fish tissue criteria that are being used as TMDL targets are 

based on concentrations of methylmercury, but the states are actually measuring total mercury in 

fish instead of methylmercury. It is assumed that approximately 90 percent of total mercury in 

fish is methylmercury, so if states are meeting a concentration of 0.1, 0.2, or 0.3 ppm total 
Northeast Regional Mercury TMDL – October 2007 34 

mercury, the concentration of methylmercury is actually about ten percent lower than this value, 

allowing for another level of protection. 

7.8 Seasonal Variation and Critical Conditions 

Seasonal variations and “...critical conditions for stream flow, loading, and water quality parameters” are 

discussed in 40 CFR 130.7(c)(1). The regulation provides that: “for pollutants other than heat, TMDLs 

shall be established at levels necessary to attain and maintain the applicable narrative and numerical 

WQS with seasonal variations and a margin of safety which takes into account any lack of knowledge 

concerning the relationship between effluent limitations and water quality. Determinations of TMDLs 

shall take into account critical conditions for stream flow, loading, and water quality parameters”. 

Mercury deposition and concentrations in water vary due to seasonal differences in rain and wind 

patterns, but this variation is not relevant because mercury concentrations in fish represent accumulation 

over their life spans. Factors such as size and waterbody conditions have greater effect on mercury 

concentrations than seasonal variation. 

There are some factors, such as water chemistry and water level fluctuations that make conditions more 

favorable for mercury accumulation in fish. However, these are not short term critical conditions, but 

rather factors that contribute to the accumulation of mercury in fish over long periods of time. More 

information is provided on sensitive areas and critical conditions in Section 4.2. 

7.9 Daily Load 

Because this TMDL addresses mercury accumulation in fish over long periods of time, annual loads are 

more appropriate for expressing mercury loading goals. Therefore, the calculations and compliance with 

this TMDL are based on annual loads. However, in order to comply with current EPA guidance, the 

TMDL is also expressed as a daily load. 

8 Final TMDL 

The conventional equation for a TMDL is as follows: TMDL = WLA+LA+MOS. As described in 

Section 7.7, the MOS is implicit for this TMDL, and therefore, it is not necessary to include an explicit 

MOS in the calculations. Calculation of the WLA and LA are described in Sections 7.5 and 7.6 

respectively. The final TMDLs for the Northeast region are shown below for both annual and daily loads. 

The values shown correspond to use of the 80th to 90th percentile existing mercury concentrations in 

smallmouth bass to calculate the TMDL as discussed in Section 5.2. The target of the TMDL is 90th

percentile. 

TFMC TMDL Annual Load 80th Percentile TMDL Annual Load 90th Percentile 

0.3 TMDL (2,319 kg/yr) = 

WLA (49 kg/yr) + LA (2,269 kg/yr) 

TMDL (1,749 kg/yr) = 

WLA (37 kg/yr) + LA (1,712 kg/yr)

0.2 TMDL (1,546 kg/yr) = 

WLA (33 kg/yr) + LA (1,513 kg/yr) 

TMDL (1,166 kg/yr) = 

WLA (25 kg/yr) + LA (1,141 kg/yr)

0.1 TMDL (773 kg/yr) = 

WLA (16 kg/yr) + LA (756 kg/yr) 

TMDL (583 kg/yr) = 

WLA (12 kg/yr) + LA (571 kg/yr)
Northeast Regional Mercury TMDL – October 2007 35 

TFMC TMDL Daily Load 80th Percentile TMDL Daily Load 90th Percentile 

0.3 TMDL (6.4 kg/d) = 

[WLA (51 kg/yr) + LA (2,269 kg/yr)]/365 

TMDL (4.8 kg/d) = 

[WLA (38 kg/yr) + LA (1,712 kg/yr)]/365

0.2 TMDL (4.2 kg/d) = 

[WLA (51 kg/yr) + LA (2,269 kg/yr)]/365 

TMDL (3.2 kg/d) = 

[WLA (38 kg/yr) + LA (1,712 kg/yr)]/365

0.1 TMDL (2.1 kg/d) = 

[WLA (17 kg/yr) + LA (756 kg/yr)]/365 

TMDL (1.6 kg/d) = 

[WLA (13 kg/yr) + LA (571 kg/yr)]/365

The WLA is defined for this mercury TMDL as 2.1 percent of the TMDL to ensure that water point 

source mercury loads remain small and continue to decrease.

9 Implementation 

This regional TMDL will be implemented using adaptive implementation in order to ensure calculated 

reduction targets are appropriate as measured mercury fish tissue concentrations decline. It is expected 

that states will continue fish tissue monitoring at the same level that has been conducted in recent years, 

provided that sufficient funding is available. If monitoring shows that fish tissue concentrations have 

declined to levels that meet water quality standards before the calculated percent reduction in 

anthropogenic loadings is achieved, targets will be adjusted based on that monitoring. 

Implementation has been divided into three phases. The timeline and goals for the first two phases 

align with the NEG-ECP Regional MAP. Phase I is from 1998 to 2003 with a goal of 50 percent 

reduction and Phase II is from 2003 to 2010 with a goal of 75 percent reduction. The goal of Phase III 

will be to make any further necessary reductions to meet the target fish mercury concentrations. 

However, the exact timeline and reduction goal for this phase cannot be determined until mercury 

emissions, deposition, and fish tissue concentrations are re-evaluated in 2010. The goal for Phase III may 

or may not match the percent reduction that current calculations show. To meet the necessary reductions 

required in Phase III, major air point sources will be addressed through the application of more stringent 

control technology requirements and/or emission limits, economically and technically feasible/achievable, 

taking into account advances in the state of air pollution controls and the application of transferable 

technologies used by other sources to achieve maximum emission reductions. Emissions from area 

sources will be controlled to the maximum extent feasible using best management practices and pollution 

prevention approaches. 

9.1 State and Regional Implementation 

9.1.1 Implementation of Wasteload Allocation 

In 2005, it was estimated that approximately 72 percent of dentists in New England had installed 

amalgam separators. As the point source load for this TMDL was based on data from 1988 to 2005, the 

regional point source load has most likely already significantly decreased as a result of amalgam separator 

installation. As of 2006, all of the Northeast states have legislation or regulations that require installation 

of amalgam separators, which will further reduce mercury loads in wastewater. As of 2006, all of the 

Northeast states have comprehensive mercury products legislation. This will result in additional 

reductions in mercury concentrations in wastewater by reducing mercury input from household uses. As 

was discussed in Section 7.5, this TMDL places much emphasis on the fact that the states have agreed to 

a goal of virtual elimination of mercury. Individual laws and requirements vary by state, but legislation 

addresses bans on disposal of mercury-added products, bans on sale or distribution of mercury-added 
Northeast Regional Mercury TMDL – October 2007 36 

novelties and measuring devices, requirements for installing amalgam separators, requirements for 

labeling of mercury-added products, prohibition of primary and secondary schools purchasing or using 

mercury, removal of mercury switches from automobiles, and requirements on recycling of mercuryadded products. The end result of all these mercury minimization efforts is that a smaller quantity of 

mercury makes its way into the waste stream and less mercury is discharged from wastewater treatment 

facilities. More details on state reduction plans can be found in Appendix D. These efforts undoubtedly 

increase the likelihood of successfully implementing the waste load allocation. Because these reduction 

efforts are on-going the states feel there is little else that could be done through the NPDES program that 

could further ensure that the WLA will not be exceeded. However, states will conduct investigations, as 

appropriate, on a permit by permit basis, to prevent localized exceedances of the WLA. 

Reductions in the mercury load in stormwater are expected to be achieved through reductions in 

atmospheric deposition, the primary source of mercury in stormwater. Regulated stormwater is considered 

to be part of the de minimis WLA, and will be addressed through the controls on atmospheric deposition 

sources that are required to meet the load allocation. The states anticipate that once atmospheric 

deposition reductions are met, the only remaining regulated stormwater contributions would be solely 

attributed to natural sources and run-off from localized non-atmospheric sources. This residual 

stormwater contribution is considered to be a minute part of the WLA. 

The states are already engaged in controlling stormwater pollution using best management practices 

(BMPs) in accordance with Clean Water Act §402(p) and 40 CFR 122.44(k) and any residual mercury in 

stormwater that originates from non-atmospheric sources can be addressed by these programs. The six 

minimum measures associated with permits for municipal separate storm sewer systems (MS4s) will 

contribute toward reducing mercury loading by reducing stormwater volume and sediment loading. 

The WLA in this TMDL is regional and is not specific to each particular state or source. Instead of 

allocating the WLA among sources, mercury reduction will be accomplished through mercury 

minimization plans (MMPs) and the continuation of region-wide mercury reduction efforts as described 

above. MMPs help ensure that discharges have no reasonable potential to cause or contribute to an 

exceedance of water quality standards. EPA believes that a requirement to develop a MMP may provide 

dischargers with sufficient information to voluntarily and economically reduce mercury discharges (EPA 

2006a). Evaluation of progress at the Phase II milestone will determine if mercury minimization plans 

and additional monitoring at point sources should be prescribed for dischargers that do not already have 

those programs in place. All new or increased discharges will be required to stay below the regional 

WLA. 

9.1.2 Adaptive Implementation of Load Allocation 

EPA’s Clean Air Mercury Rule (CAMR) became effective May 18, 2006. All states that received a 

mercury budget under CAMR are required to either comply with the rule or develop their own rule. 

Because they do not have any coal-fired utilities, Rhode Island and Vermont did not receive a mercury 

budget under CAMR and are therefore not required to develop a state plan (NACAA 2007). The five 

remaining Northeast states have chosen to develop their own rules. None of the Northeast states will 

participate in the interstate trading that is allowed under CAMR. Table 9-1 provides a summary of state 

rules. Implementation of these state-based rules will go a long way toward meeting the deposition goals 

set by this TMDL, as coal-fired utilities are one of the most significant sources of emissions in the region. 
Northeast Regional Mercury TMDL – October 2007 37 

Table 9-1 Northeast State Mercury Control Programs for Coal-Fired Utilities 

State Rule 

CT On or after July 1, 2008, coal-fired utilities are required to meet an emissions rate equal to or less 

than 0.6 lbs of mercury per trillion British thermal units (TBtu) or meet a rate equal to 90 percent 

reduction, whichever is more readily achievable. On or before January 1, 2012, CT DEP will 

conduct a review of mercury emission limits applicable to affected units and may adopt 

regulations to impose more stringent limits. 

ME Currently all coal-fired utilities and other facilities in Maine have a mercury emissions limit of 

50 lbs/yr. Recently enacted legislation changes the limit to 35 lbs/yr in 2007 and 25 lbs/yr in 

2010. A mercury reduction plan would also be required for any facility emitting more than 10 

lbs/yr. 

MA Phase I, which takes effect January 1, 2008, requires that each facility capture at least 85 percent 

of mercury in the coal burned, or emit no more than 0.0075 lbs of mercury per net gigawatt-hour 

of electricity generated. Phase II, which takes effect October 1, 2012, requires that facilities 

capture at least 95 percent of the mercury in coal burned, or emit no more than 0.0025 lbs of 

mercury per net gigawatt-hour of electricity generated. 

NH An Act Relative to the Reduction of Mercury Emissions provides for 80 percent reduction of 

mercury emissions from coal-burning power plants by requiring installation of scrubber 

technology no later than July 1, 2013 and provides economic incentives for earlier installation 

and greater reductions in emissions. 

NY Phase I requires a 50 percent decrease by January 1, 2010 and Phase II will implement a unitbased limit for each power plant facility. This will result in an estimated 90 percent decrease 

from current levels, which will result in total emissions of 150 lbs/yr or less. 

In addition to enforceable controls on coal-fired utilities, the next phase of the NEG-ECP MAP focuses 

on working toward reductions from four other sectors: sewage sludge incinerators (SSIs), MWCs, area 

sources, and residential heating/commercial and industrial oil combustion. SSIs will be addressed by the 

now mandatory installation of amalgam separators in all Northeast states and reducing use of mercuryadded products by consumers and the health care sector. Reductions will be achieved from MWCs by 

pollution prevention efforts, mercury-added product legislation, and possibly enhanced pollution controls. 

Emissions from area sources are likely to decrease as a result of pollution prevention initiatives. Limited 

data on the residential heating/commercial and industrial oil combustion sectors make it difficult to set 

emissions targets for this sector, but emissions can be reduced through modifications to fuels combusted, 

shifting to lower mercury oils, energy conservation efforts, and increased use of renewable energy 

sources. 

Through the NEG-ECP MTF process, New England states have made a commitment toward the virtual 

elimination of mercury. As mentioned previously, while New York State is not a member of the NEGECP, they too have made a state-wide commitment to reduce mercury. These goals and commitments are 

complimentary to this TMDL. Between 1998 and 2002, regional mercury deposition was reduced by 

approximately 74 percent. Since 2002, a number of mercury reduction programs have been implemented 

and many regulations have passed, to further reduce regional mercury deposition. However, as updated 

deposition modeling has not been undertaken, these reductions are not yet quantifiable. The regional 

emissions inventory and deposition modeling will be updated in 2010. With the implementation of 

reduction programs and legislation since 2002, and full implementation of legislation that has been 

passed, the Northeast states are addressing all mercury sources within their control. More information on 

state mercury reduction efforts is provided in Appendix D. 
Northeast Regional Mercury TMDL – October 2007 38 

This TMDL includes an in-region implementation plan that takes into account the significant reductions 

already made by the Northeast states and the need for updated emissions inventory and deposition 

modeling at the end of Phase II. An appropriate implementation plan based on that updated information 

will be developed for Phase III. Because the Northeast states are already addressing all mercury sources 

within their control, additional controls are not expected of in-region sources as part of the 

implementation for Phases I and II. In order for this TMDL to be fully implemented, greater reductions 

are needed from out-of-region sources. 

9.2 Adaptive National Implementation 

As this TMDL has shown, there is a need to make significant reductions in anthropogenic emissions of 

mercury in order to meet states’ water quality standards. The Northeast states demonstrate below through 

their assurances that significant regional reductions have already been met and continuing reductions will 

be made. Research undertaken by states has shown that significant reductions in mercury emissions 

translate into timely and significant reductions in fish tissue concentrations. As described further in 

Section 10.1, MassDEP has seen timely and significant decreases in fish tissue mercury concentrations 

with a decrease in local mercury emissions (Hutcheson, et al. 2006). Timely reductions will yield 

immediate public health and environmental quality improvements for the Northeast states. 

CAMR became effective May 18, 2006. The first phase of the rule, which will be achieved in 2010, will 

reduce emissions nationwide by about 21 percent. The second phase will reduce emissions by about 70 

percent and will be achieved sometime after 2018. This phasing of the national CAMR is insufficient to 

meet the adaptive implementation of this TMDL. The rule established a cap-and-trade program, which 

will allow power plants to purchase emissions reduction allowances from other power plants and 

potentially bank these allowances to meet compliance requirements in future years. 

Prior to the finalization of CAMR, EPA was considering two options for controlling mercury emissions 

from coal-fired power plants. The first option would mean EPA would, pursuant to Section 112(n) of the 

CAA, set National Emission Standards for Hazardous Air Pollutants (HAPs) for power plants and adopt a 

Maximum Achievable Control Technology (MACT) standard for mercury. The second option would 

revise EPA’s December 2000 determination that regulation of power plants under Section 112(n) was 

“necessary and appropriate.” With the finalization of CAMR, EPA chose the second option and used 

Section 111 of the CAA to set standards for mercury emissions. EPA determined that regulation of 

mercury under a cap-and-trade program was sufficient to protect public health. 

As the Northeast states have argued in the Opening Brief of Government Petitioners dated January 11, 

2006 in the matter of State of New Jersey, et al. vs. United States Environmental Protection Agency, the 

implementation of a strict plant-specific MACT for mercury under section 112(d) of the CAA would 

result in at least 90 percent control of mercury emissions by cost-effective and available technologies. 

Further, enacting a MACT standard under section 112(d) would require compliance within three years of 

the effective date of the standard. 

This TMDL adds a second dimension to the legal arguments presented by the Northeast states in the 

lawsuit mentioned above by calculating for the first time the extent of reductions needed to meet water 

quality standards in the region’s listed waters and remove fish consumption advisories. This TMDL 

further establishes the need for emissions reductions over much shorter timeframes. Research conducted 

in Massachusetts shows that mercury emission reductions can quickly translate into reductions in fish 

tissue concentrations. 
Northeast Regional Mercury TMDL – October 2007 39 

The Northeast states are recommending adaptive implementation of this TMDL and that a strict 90 

percent MACT standard enacted under section 112(d) be promulgated to meet the national 

implementation requirements of the TMDL for Phase II (2003-2010, 75 percent reduction). As discussed 

previously, this TMDL calls for a 98 percent reduction in order to meet the initial target fish tissue 

concentration. However, the TMDL will be implemented adaptively, so that as regional and national 

controls are implemented, the response in fish tissue as a result of emissions and deposition reductions 

will be monitored. If necessary, reduction goals will be modified based on the response seen in fish tissue 

monitoring. 

A significant portion of mercury deposited in the Northeast originates from global sources. While the 

federal government cannot place controls on these sources, the government can reduce the mercury 

entering other countries by prohibiting sale of the country’s stockpiles of mercury. The Northeast states 

recommend that sale of United States stockpiles of mercury are prohibited in order to reduce mercury 

emissions and deposition from international sources. 

10 Reasonable Assurances 

This regional TMDL for mercury allocates the reduction of pollutant sources to waterbodies throughout 

the Northeast between point sources, which have been classified as de minimis, and nonpoint sources. 

States are required to provide reasonable assurance that those nonpoint sources will meet their allocated 

amount of reductions, which can be much more challenging than documenting reasonable assurances for 

point source reductions. The actions that provide these assurances take place at the state, national, and 

international level and are described below.

10.1 State Level Assurances

There are a variety of ways in which a state or states can provide reasonable assurances. These include the 

implementation of pollution control measures, developing and implementing nonpoint source control 

plans and, if available, other state regulations and policies governing such facilities. As described in 

Section 2.3 and Appendix D, the Northeast has a strong commitment to reducing mercury in the 

environment. The New England states participate in the NEG-ECP MTF and are committed to the 

regional MAP. As part of the MAP, the New England states have adopted emission limits for large 

MWCs that are three times more stringent than what EPA requires. This has already resulted in a 90 

percent reduction in emissions from this sector. Mercury products legislation adopted in all Northeast 

states will further reduce these emissions. The MAP also requires a limit for MWIs that is ten times more 

stringent than EPA requirements. All of the states, including New York State (which is not part of the 

MTF), have aggressive programs for mercury reduction. The MAP is an adaptive management plan with 

a goal of virtual elimination. The states’ success in meeting MAP goals demonstrates the ability of the 

Northeast states to make meaningful mercury reductions. 

In 2005, NESCAUM prepared Inventory of Anthropogenic Mercury Emissions in the Northeast to update 

their mercury emission inventory with 2002 emissions data. The project was partially undertaken to 

assist the NEG-ECP in their effort to assess progress in meeting the goals of the MAP. Table 10-1 shows 

that substantial reductions in mercury emissions have been made for the majority of sources. Overall, 

regional mercury emissions decreased by 70 percent between 1998 and 2002. The greatest decreases 

came from MWCs (87.0 percent) and MWIs (96.6 percent). These emissions reductions have resulted in 

a 74 percent reduction in atmospheric deposition of mercury, as described in Section 7.6.2. 
Northeast Regional Mercury TMDL – October 2007 40 

Table 10-1 Comparison Between 1998 and 2002 Regional Mercury Emissions Inventories1

Mercury Source Categories 1998 

Emissions 

Estimate 

(kg/yr) 

Percent of 

1998 

Inventory 

2002 

Emissions 

Estimate 

(kg/yr) 

Percent of 

2002 

Inventory 

Percent 

Decrease 

Direct Sources 

Combustion Sources 

Municipal Waste Combustors 6,896 55.2 896 23.9 87.0 

Sewage Sludge Incinerators 657 5.3 382 10.2 41.9 

Medical Waste Incinerators 758 6.1 26 0.7 96.6 

Commercial/Industrial Boilers 552 4.4 273 7.3 50.5 

Fossil Fuel-Fired 449 3.6 245 6.5 45.4 

Wood-Fired 103 0.8 29 0.8 71.8 

Electric Utility Boilers Total 864 6.9 864 23.0 0 

Coal-Fired 697 5.6 697 18.6 0 

Oil-Fired 142 1.1 142 3.8 0 

Natural Gas-Fired 18 0.1 18 0.5 0 

Wood-Fired 7 0.1 7 0.2 0 

Total Combustion Sources 9,727 77.9 2,441 65.1 74.9 

Manufacturing Sources 

Secondary Mercury Production 319 2.6 0 0 100 

Cement Manufacturing 305 2.4 239 6.4 21.6 

Lime Manufacturing 15 0.1 4 0.1 73.3 

Steel Foundries 17 0.1 17 0.5 NA 

Chlor-Alkali Facilities 460 3.7 0 0 100 

Misc. Industrial Processes 3 0.02 3 0.08 NA 

Total Manufacturing Sources 1,119 9.0 263 7.0 76.5 

Total Direct Sources 10,846 86.8 2,704 72.1 75.1 

Area Sources 

Residential Heating 575 4.6 637 17 -10.8 

Industrial Processes 1,073 8.6 411 11 61.7 

Electric Lamp Breakage 

& Recycling 

379 3.0 179 4.8 52.8 

General Lab Use 48 0.4 48 1.3 0 

Dental Preparation and 

Use 

70 0.6 66 1.8 5.7 

Crematories 70 0.6 118 3.1 -68.6 

Latex Paint 506 4.0 0 0 100 

Total Area Sources 1,648 13.2 1,048 27.9 36.4 

Total Emissions 12,494 100 3,752 100 70.0 

 

1 This direct comparison of total emissions is meant to be a rough guide. Several factors, such as new source 

categories and methodological changes, should be taken into account in the interpretation of the overall emissions 

decreases in the region. Further work is needed for a true comparison of emission reductions. More information is 

provided in NESCAUM 2005. 
Northeast Regional Mercury TMDL – October 2007 41 

In addition to region-wide reductions that provide reasonable assurances, each state has a number of 

mercury reductions programs. These programs are described below for each of the Northeast states. 

Connecticut 

In 1990, the Connecticut General Assembly adopted the Toxics in Packaging Act that required 

elimination of mercury from most packaging within two years. In 1992, Connecticut was one of the first 

states to pass a law restricting the level of mercury in alkaline batteries. The Universal Waste Rule, 

which was adopted in 2001, outlines management practices for four specific waste streams, including 

thermostats and lamps, to reduce mercury in the solid waste stream. Also in 2001, Connecticut DEP 

provided mercury education and training to used car dealers, auto recyclers, State of Connecticut fleet 

operations, and City of Hartford fleet operations. Between February 2000 and February 2001, over 283 

lbs of mercury and mercury compounds were removed from school science laboratories. 

In 2002 Connecticut enacted comprehensive legislation, An Act Concerning Mercury Education and 

Reduction, targeting the virtual elimination of discharges of anthropogenic mercury to the environment by 

establishing a program to eliminate non-essential uses of mercury in consumer, household, and 

commercial products. The first provisions were effective in 2002 and it was fully implemented in 2006. 

Mercury-containing products such as novelties, fever thermometers, and dairy manometers were banned 

from sale. After July 1, 2006 the sale or distribution of other mercury-added products containing more 

than one hundred grams or 100 parts per million of mercury is prohibited, unless the product is 

specifically exempted from the statutory phase-out requirements, or the department grants a modified or 

conditional exemption. In addition, manufacturers of mercury-added products are required to meet a 

number of other provisions under the law to notify, label and provide collection systems. CT DEP works 

closely with the Interstate Mercury Education and Reduction Clearinghouse to coordinate these actions on 

a regional basis. 

The law also places restrictions on the sale and distribution of elemental mercury and its use. Under this 

authority the Department adopted best management practices on the use and handling of mercury in 

dental offices, among other practices, requiring the installation of amalgam separators to trap and remove 

mercury amalgam from their wastewater discharges. 

In 2000, CT DEP revised their air regulations to require stringent controls on resources recovery facilities. 

Sources subject to the regulation were required to meet an emission limit of 0.80 mg/dry standard cubic 

meter (dscm) (an 85 percent reduction) by December 2000 and to reduce to 0.028 mg/dscm by June 2002. 

As discussed in Section 9.1, Connecticut has passed legislation that will decrease emissions from coalfired power plants by at least 90 percent. 

Maine 

Maine has a law that bans the disposal of mercury-added products and requires that all mercury-added 

products are recycled. As of January 1, 2002 the sale of mercury fever thermometers is banned in Maine, 

mercury-added products must be labeled to clearly inform the purchaser or consumer that mercury is 

present, and the product must be disposed of properly. All dental offices were required to install 

amalgam separators by December 31, 2004. As of January 1, 2006 the sale of mercury-added thermostats 

is banned. Effective July 1, 2006 mercury-added barometers, esophageal dilators, flow meters, 

hydrometers, hygrometers, manometers, pyrometers, sphygmomanometers, and thermometers cannot be 

sold in Maine. Also effective the same day, mercury switches or relays cannot be sold individually or as 

a product component. Incineration and landfill disposal of cathode ray tubes was banned after January 1, 

2006. An Act to Regulate Use of Batteries Containing Mercury was signed into law in March 2006 and 

provides for labeling of button cell batteries that contain mercury, prohibits disposal of these batteries in 
Northeast Regional Mercury TMDL – October 2007 42 

landfills and incinerators, and requires retailers to provide for take back of these batteries from customers. 

An Act to Limit Human Exposure to Mercury has a goal to transition to mercury-free dentistry. An Act 

to Require that Hazardous Waste be Removed from Junked Vehicles includes a requirement for removal 

of mercury switches. 

As described in Section 9.1, currently all facilities in Maine have a mercury emissions limit of 50 lbs/yr. 

Recently enacted legislation makes the limit more strict and requires a mercury reduction plan for any 

facility emitting more than 10 lbs/yr. In addition, all facilities with a wastewater discharge are subject to 

the requirements of Interim Effluent Limitations and Controls for the Discharge of Mercury, 06-096 CMR 

519 (effective February 5, 2000) which require effluent limits be established and that all facilities develop 

and implement a mercury pollution prevention plan. All facilities in the state are in compliance with this 

rule. 

Massachusetts 

The Mercury Management Act, passed in 2006, requires end-of-life recycling of mercury-containing 

products, prohibits disposal of mercury in trash and wastewater, bans the sale of specific products 

containing mercury, directs schools and state government to stop purchasing mercury-containing items, 

establishes a program for removing switches from vehicles, and requires manufacturers both to notify the 

state of products with mercury content, and to establish end-of-life collection and recycling programs. In 

April 2006, regulations took effect that require most dental practices and facilities in Massachusetts to 

install and operate amalgam separator systems, recycle mercury-containing amalgam wastes, and 

periodically certify their compliance with the requirements. Prior to the regulations, MassDEP 

implemented a voluntary program with the Massachusetts Dental Society to encourage early installation 

and use of amalgam separators by dentists. 

The Municipal Waste Combustor Rule required facilities with a capacity greater than 250 tons/day to 

meet an emissions standard of 28 μg/dcsm by December 2000 and to develop material separation plans 

for products containing mercury. Massachusetts also has strict controls on mercury emissions from coalfired power plants. These regulations are described in more detail in Section 9.1 

MassDEP recently conducted a study to examine changes in fish tissue mercury concentrations in an area 

of Northeastern Massachusetts with elevated mercury deposition due to local emissions sources. Over the 

study period, local mercury emissions decreased by 87 percent, and as a result, fish tissue mercury 

concentrations decreased an average of 25 to 32 percent (Hutcheson, et al. 2006). Consistent decreases 

were seen 48 months after emissions controls were put in place. This response time was much shorter 

than was expected. The results of this study emphasize the point that decreases in mercury emissions can 

result in timely decreases in fish mercury concentrations. 

New Hampshire 

New Hampshire legislation puts restrictions on the mercury content of batteries and establishes 

notification requirements for manufacturers of mercury-added products. New Hampshire has a ban on the 

sale of toys, games, cards, ornaments, or novelties that contain mercury and mercury fever thermometers. 

No school can use or purchase elemental mercury, mercury compounds, or mercury-added instructional 

equipment and materials in a primary or secondary classroom. Legislation required all dental practices to 

install amalgam separators by October 2005. 

Any MWC with a design capacity to burn 100 tons/day or more must reduce emissions to achieve no 

more than 0.028 mg/dscm or at least 85 percent control efficiency. All MWIs must achieve an emissions 
Northeast Regional Mercury TMDL – October 2007 43 

limit of 0.055 mg/dscm. As described in Section 9.1, New Hampshire recently passed legislation to limit 

mercury emissions from coal-fired power plants. 

New York 

A law adopted in September 2005 prohibits the sale and distribution of some mercury-added products 

including thermostats, barometers, esophageal dilators, bougie tubes, gastrointestinal tubes, flow meters, 

hydrometers, hygrometers, psychrometers, manometers, pyrometers, sphygmomanometers, thermometers, 

and switches and relays. The law also requires manufacturers and trade associations dealing in mercuryadded products to report certain information to NYS DEC. Regulations effective in May 2006 prohibit 

the use of non-encapsulated elemental mercury in dental offices and require dentists to recycle any 

elemental mercury or dental amalgam waste generated in their offices. Dental facilities are required to 

install, properly operate, and maintain mercury amalgam separation and collection equipment. Although 

not mandated by law, New York State is working on pollution prevention efforts for health care facilities, 

an automobile switch collection and recycling project, and a dairy manometers identification and removal 

program. 

New York State has an emission limit for large MWCs (greater than 250 tons/day) of 28 μg/dscm or 85 

percent removal, whichever is less stringent. Regulations were recently passed for coal-fired utilities, the 

details of which are provided in Section 9.1 

Rhode Island 

The Mercury Reduction and Education Act requires the phase-out of mercury-added products, labeling, 

collection plans, bans on certain products, and elimination of mercury from schools. No mercury fever 

thermometers can be sold after January 1, 2002. After January 1, 2003, no mercury-added novelty can be 

sold in Rhode Island, unless its only mercury component is one or more mercury-added button cell 

battery. No school can use or purchase for use bulk elemental or chemical mercury or mercury 

compounds for use in primary or secondary classrooms. After January 1, 2006 mercury-added products 

can only be disposed of through recycling or disposal as hazardous waste. Legislation now requires 

removal and collection of mercury switches from automobiles. RI DEM currently has a voluntary self 

certification program for installation of amalgam separators, and legislation that passed in 2006 requires 

dental offices to install amalgam separators by July 2008. 

Rhode Island has a mercury emissions limit of 0.055 mg/dscm for all MWIs. 

Vermont 

Vermont passed the nation’s first mercury labeling law in 1997 and then passed Comprehensive 

Management of Exposure to Mercury in 2005, with amendments in 2006. This law establishes a 

comprehensive approach to reducing the exposure of citizens to mercury released in the environment 

through mercury-added product use and disposal, including requirements that manufacturers of mercuryadded products provide notice to the agency and report on total mercury contained in certain products, a 

ban on the distribution or offering for sale of mercury-added novelties, fever thermometers, thermostats, 

and dairy manometers, and other devices, and to modify the existing labeling requirements for mercuryadded products and packaging by expanding the types of products subject to labeling. It also bans the 

disposal of mercury-added products such as thermostats, thermometers, automobile switches, and bulbs in 

landfills and incinerators, requires source separation of discarded mercury-added products, and requires 

solid waste management facilities to inform customers of disposal bans and collection programs for 

mercury-added products. The law also prohibits purchase and use of mercury-added products and 

elemental mercury in primary and secondary schools. Dental practices are required to follow mercury 
Northeast Regional Mercury TMDL – October 2007 44 

waste management practices as established by the State of Vermont and Vermont State Dental Society 

and to install dental amalgam separators by January 2007. Hospitals are required to submit a mercury 

reduction plan to the agency every three years. 

10.2 National and International Assurances 

The Northeast region’s ability to achieve the calculated TMDL allocations is dependent on the adoption 

and effective implementation of national and international programs to achieve necessary reductions in 

mercury emissions. Given the magnitude of the reductions required to implement the TMDL, the 

Northeast cannot reduce in-region sources further to compensate for insufficient reductions from out-ofregion sources. While EPA and the federal government are involved in the programs described below, 

further efforts are necessary to assure that the goals of this TMDL are met. Specifically, it is Northeast 

States’ position that the data and analyses in this TMDL demonstrate that: 

(A.) CAMR will be insufficient to achieve the reduction needed to achieve the water quality goals set 

forth in this TMDL, 

(B.) EPA must implement significant reductions from upwind out-of-region sources, primarily coal-fired 

power plants; and 

(C.) MACT provisions of section 112(d) of the CAA should be adopted as the mechanism for 

implementing this TMDL. 

Further, the States note that EPA has the authority to revise CAMR or otherwise require the necessary 

reduction on a national scale to meet the goals set by this TMDL. 

National assurances are also found within EPA’s obligation under both section 112 of the CAA and the 

loading reduction requirements of the TMDL provisions in section 303(d) of the Clean Water Act to act 

to immediately reduce the emission of mercury from these sources. The timeline for the reduction goals 

of this TMDL are set forth in Section 9. 

CAMR, which regulates mercury emissions from Electrical Generating Units (EGUs) under section 

111(d) of the CAA, requires an eventual reduction in mercury emissions of 70 percent at full 

implementation of the rule, sometime after 2018. CAMR is a two-phase rule, with the first phase 

requiring reductions in mercury of approximately 20 percent coming as a co-benefit of reductions in 

sulfur dioxide and nitrous oxides to be made by 2010. Between 2010 and 2018, the CAMR provides for a 

cap and trade program that is proposed to make further reductions with eventual reductions of 70 percent 

sometime after 2018.1

 

For further national assurances, the Northeast states are recommending adaptive implementation of this 

TMDL and that a strict 90 percent MACT standard be enacted under section 112(d) be promulgated to 

meet the national implementation requirements of the TMDL for Phase II (2003-2010). As discussed 

previously, this TMDL calls for an 87 percent reduction in order to meet the initial target fish tissue 

concentration. However, the TMDL will be implemented adaptively, so that as regional and national 

controls are implemented, the response in fish tissue as a result of emissions and deposition reductions 

will be monitored. If necessary, reduction goals will be modified based on the response seen in fish tissue 

monitoring. 

 

1

 The Northeast states have filed a suit (State of New Jersey, et al. vs. United States Environmental Protection 

Agency) against U.S. EPA challenging CAMR’s legality – how its limits were calculated and the establishment of 

the trading program. 
Northeast Regional Mercury TMDL – October 2007 45 

Additional national mercury reduction programs include the National Vehicle Mercury Switch Recovery 

Program, which will cut mercury emissions by up to 75 tons over the next 15 years by removing mercurycontaining light switches from scrap vehicles before they are flattened, shredded, and melted to make new 

steel. EPA was a founder of Hospitals for a Healthy Environment (H2E), a movement to promote 

environmental sustainability in health care. Among H2E’s goals is the virtual elimination of mercury 

waste. 

The Commission for Environmental Cooperation (CEC) is an international organization created by 

Canada, Mexico, and the United States under the North American Agreement on Environmental 

Cooperation. It was established to address regional environmental concerns, help prevent potential trade 

and environmental conflicts, and promote effective enforcement of environmental law. The CEC has 

developed the North American Regional Action Plan (NARAP) on Mercury with the goal of reducing 

man-made mercury releases to North America through international and national initiatives. The NARAP 

has provisions regarding risk management approaches to address mercury emissions, processes, 

operation, and products; waste management; and research, monitoring, modeling, inventories, and 

communication activities. 

The United Nations Environment Programme (UNEP) established its Mercury Programme in 2003. The 

program has a long-term objective “to substantially reduce or eliminate uses and anthropogenic releases 

of mercury through the implementation of national, regional and global actions, thereby significantly 

reducing global adverse impacts on health and the environment”(United Nations Environment 

Programme 2006). Among other actions, the UNEP Mercury Programme will assist countries to identify 

and understand mercury problems in their countries and implement actions to mitigate them. 

11 Public Participation 

As this is a regional TMDL that covers seven states, the public participation process was dictated by each 

state’s procedure for public notice of a TMDL. The TMDL was posted on NEIWPCC’s website, as well 

as the websites of each of the participating state agencies. Many states posted notices of the TMDL in 

local newspapers. Table 11-1 provides information about the public participation actions undertaken by 

each of the states. 

Table 11-1 Public Participation Actions Undertaken by the Northeast States 

CT ME MA NH NY RI VT 

Notice of TMDL on state agency website X X X X X X X 

TMDL posted on state agency website X X X X X X X 

Notice of TMDL posted in newspaper X X X X X X 

Public meeting held X X X X X 

Press release issued X X X X X 

Notices sent to target groups with potential interest in TMDL X X 

Following the April 11, 2007 release of the draft TMDL, articles were published in several local, regional, 

and national publications including the Boston Globe, New York Times, Greenwire, and Water Policy 

Report. There was a 59-day comment period during which eight public meetings were conducted 

throughout the region. The schedule and locations for the public meetings are listed below: 

April 25, 2007 – Providence, RI 

April 30, 2007 – Worcester, MA 

May 1, 2007 – Boston, MA 
Northeast Regional Mercury TMDL – October 2007 46 

May 2, 2007 – Syracuse, NY 

May 3, 2007 – White Plains, NY 

May 4, 2007 – Ballston Spa, NY 

May 10, 2007 – Concord, NH 

May 11, 2007 – Waterbury, VT 

A total of 30 people attended the eight public meetings. NEIWPCC and the states received comments 

from 14 different groups. Following the comment period, the TMDL technical team considered all 

comments received, prepared a response to comments document (see Appendix E), and made necessary 

revisions to the TMDL. 
Northeast Regional Mercury TMDL – October 2007 47 

12 References

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Committee on the Environment of the Conference of New England Governs and Eastern Canadian 

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Evers, D.C. 2005. Mercury Connections: The Extent and Effects of Mercury Pollution in Northeastern 

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Chen, T.A. Clair, and T. Butler. 2007. Biological Mercury Hotspots in the Northeastern United States and 

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Dricsoll, C.T., D. Evers, K.F. Lambert, N. Kamman, T. Holsen, Y-J. Han, C. Chen, W. Goodale, T. 

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Vol. 1, no. 3. 

 

Florida Department of Environmental Protection. 2003. The Everglades Mercury TMDL Pilot Study: 

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2006, Newport, RI. 

Hellyer, G. 2006. Connecticut River Fish Tissue Contaminant Study (2000). U.S. Environmental 

Protection Agency New England Regional Laboratory, North Chelmsford, MA. 

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2006. Temporal Fish Tissue Mercury Concentration Changes During a Period of Major Mercury 

Emissions Reductions in Massachusetts. Presentation at the Northeast Regional Mercury Science and 

Policy Conference, April 27, 2006, Newport, RI. 

Kamman, N.C. and D.R. Engstrom. 2002. Historic and Present Fluxes of Mercury to Vermont and New 

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Northeast North America – A Geographic Perspective Based on Fish Tissue Monitoring Databases. 

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Kamman, N.C., C.T. Driscoll, R. Estabrook, D.C. Evers, and E.K. Miller. 2004. Biogeochemistry of 

Mercury in Vermont and New Hampshire Lakes: An Assessment of Mercury in Water, Sediment, and 

Biota of Vermont and New Hampshire Lakes. 

Kamman, N.C., D.C. Evers, C.T. Driscoll, W. Goodale, T. Holsen, N.M. Burgess, K. Fallon-Lambert, and 

Y. Han. 2006. Evaluating Changes in Mercury in Fish and Other Biota from Waterbodies Across 

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NESCAUM and the New England Governors and Eastern Canadian Premiers Mercury Task Force. 2004. 

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Northeast Regional Mercury TMDL – October 2007 49 

Norton, S.A., E.R. Perry, T.A. Haines, and A.C. Dieffenbacher-Krall. 2004. Paleolimnological 

Assessment of Grove and Plow Shop Ponds, Ayer, Massachusetts, USA – A Superfund Site. Journal of 

Environmental Monitoring. 6(5): 457-465. 

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Seigneur, C., K. Lohman, K. Vijayaraghavan, and R. Shia. 2003. Contributions of Global and Regional 

Sources to Mercury Deposition in New York State. Environmental Pollution. 123: 365-373. 

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Switzerland. 

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Agency, Washington, DC. 

U.S. EPA. 2001. Mercury Maps: A Quantitative Spatial Link Between Air Deposition and Fish Tissue. 

EPA-823-R-01-009. U.S. Environmental Protection Agency, Office of Water, Washington, D.C. 

U.S. EPA. 2002. 2000 National Water Quality Inventory. EPA 841-R-02-001. U.S. Environmental 

Protection Agency, Office of Water, Washington, DC. 

U.S. EPA. 2005. Guidance for 2006 Assessment, Listing and Reporting Requirements Pursuant to 

Sections 303(d), 305(b), and 314 of the Clean Water Act. U.S. Environmental Protection Agency, Office 

of Water, Washington, D.C. 

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Criterion. EPA 823-B-04-002. U.S. Environmental Protection Agency, Office of Water, Washington, 

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U.S. EPA. 2006b. EPA’s Roadmap for Mercury. EPA-HQ-OPPT-2005-0013. U.S. Environmental 

Protection Agency, Washington, D.C. 

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Environmental Protection Agency, Office of Water, Washington, D.C. 

Vermont Department of Environmental Conservation. 2006. State of Vermont 2006 303(d) List of 

Impaired Waters. 
Northeast Regional Mercury TMDL – October 2007 50 

Appendix A: Northeast Waters Impaired Primarily by Atmospheric Deposition of Mercury 

Connecticut

Connecticut’s 2006 list of Waterbodies Not Meeting Water Quality Standards contains the following 

language regarding listing of waters based on statewide fish consumption advisories for mercury: 

“In addition to those waters included on the list, all waterbodies where statewide fish consumption 

advisories have been established due to atmospheric deposition of mercury from sources outside of state 

jurisdictional borders are implicitly included in EPA Category 5 (“303(d) listed”). Specific fish 

consumption advisories established as a result of local pollution sources (i.e. releases of polychlorinated 

biphenyls – PCBs or chlordane) are individually listed in Appendix C-4.” 

Because the Northeast Regional TMDL only covers freshwaters, all waters that are not designated as “E” 

(for estuary) by the state of Connecticut are included, with the exception of the waterbodies listed below 

that are known to have significant mercury contributions from more localized sources. 

 Unnamed tributary to the Oyster River (Milford)-02 (CT5000-55_02) 

 Wyassup Lake (North Stonington) (CT-1001-00-1-L1_01) 

 Dodge Pond (East Lyme) (CT2205-02-1-L1_01) 

 Little River (Sprague)-02 (CT3805-00_02) 

 Papermill Pond (Sprague) (CT3805-00-3-L6_01) 

 Versailles Pond (Sprague) (CT3805-00-3-L7_01) 

 Compensating Res. (L.McDonough) (Barkhamsted/New Hartford) (CT4308-00-1-L2_01) 

 Silver Lake (Berlin/Meriden) (CT4601-00-1-L2_01) 

 Konkapot River-01 (CT6004-00_01) 

 Success Lake (Bridgeport) (CT7103-00-2-L3_01) 

 Stillman Pond (Bridgeport) (CT-7103-00-2-L4_01) 

Maine

In their 2006 Integrated List, Maine DEP lists waters impaired by atmospheric deposition of mercury in 

Category 5C: Waters Impaired by Atmospheric Deposition of Mercury. Regional or National TMDL 

may be Required. The description for this category is as follows: 

“Impairment caused by atmospheric deposition of mercury and a regional scale TMDL is required. 

Maine has a fish consumption advisory for fish taken from all freshwaters due to mercury. Many waters, 

and many fish from any given water, do not exceed the action level for mercury. However, because it is 

impossible for someone consuming a fish to know whether the mercury level exceeds the action level, the 

Maine Department of Human Services decided to establish a statewide advisory for all freshwater fish 

that recommends limits on consumption. Maine has already instituted statewide programs for removal 

and reductions of mercury sources. The State of Maine is participating in the development of regional 

scale TMDLs for the control of mercury.” 

As this TMDL only applies to freshwaters, only Maine waters designated as rivers, streams, and lakes are 

included. Any designated as marine and estuarine are not included. The Maine Integrated List does not 

single out any waterbodies that would not be included in this TMDL due to localized sources of mercury 

other than atmospheric deposition. 
Northeast Regional Mercury TMDL – October 2007 51 

Massachusetts

Based on Massachusetts Year 2006 Integrated List of Waters: Final listing of condition of 

Massachusetts’s waters pursuant to Sections 303(d) and 305(b) of the Clean Water Act. Freshwaters 

listed were found to be impaired solely as a result of atmospheric deposition. Waters where other 

potential sources could exist were excluded. 

Table A-1: Massachusetts Freshwaters Impaired Solely by Atmospheric Mercury1

Waterbody Town Segment ID 

Aaron River Reservoir Cohasset/Hingham MA94178 

Ames Pond* Tewksbury MA83001 

Ashumet Pond Mashpee MA96004 

Assabet River Reservoir Westborough MA82004 

Lake Attitash* Amesbury MA84002 

Baldpate Pond* Boxford MA91001 

Bare Hill Pond Harvard MA81007 

Big Pond Otis MA31004 

Boons Pond Stow MA82011 

Buffumville Lake Charlton MA42005 

Burr’s Pond Seekonk MA53001 

Chadwicks Pond* Haverhill MA84006 

Chebacco Lake Hamilton MA93014 

Lake Cochichewick* N. Andover MA84008 

Cornell Pond Dartmouth MA95031 

Crystal Lake* Haverhill MA84010 

Lake Dennison Winchendon MA35017 

Duck Pond Wellfleet TBD 

East Brimfield Reservoir Brimfield MA41014 

Echo Lake Milford/Hopkinton MA72035 

Flint Pond Tyngsborough MA84012 

Forest Lake* Methuen MA84014 

Forge Pond Westford/Littleton MA84015 

Fosters Pond* Andover MA83005 

Gales Pond Warwick MA35024 

Gibbs Pond Nantucket MA97028 

Great Pond Wellfleet TBD 

Great Herring Pond Bourne/Plymouth MA94050 

Great South Pond Plymouth MA94054 

Haggetts Pond* Andover MA84022 

Hamblin Pond Barnstable MA96126 

Hickory Hills Lake Lunenburg MA81031 

Holland Pond Holland MA41022 

Hood Pond Ipswich MA92025 

Hoveys Pond* Boxford MA84025 

Johns Pond Mashpee MA96157 

 

1

 Those identified by an asterisk are located in a mercury hot spot area and are not covered by this TMDL. 

Implementation of this TMDL may result in significant reductions in fish mercury concentrations or possibly 

achieve standards in this area at a future date. 
Northeast Regional Mercury TMDL – October 2007 52 

Waterbody Town Segment ID 

Johnsons Pond* Groveland/Boxford MA84027 

Kenoza Lake* Haverhill MA84028 

Knops Pond/Lost Lake Groton MA84084 

Lake Lashaway N. Brookfield/E. Brookfield MA36079 

Lewin Brook Pond Swansea MA61011 

Locust Pond Tyngsborough MA84031 

Long Pond Dracut/Tyngsborough MA84032 

Long Pond Rochester MA95097 

Lowe Pond* Boxford MA92034 

Martins Pond N. Reading MA92038 

Mashpee Pond Mashpee/Sandwich MA96194 

Massapoag Lake Sharon MA73030 

Massapoag Pond Dunstable/Groton/Tyngsborough MA84087 

Miacomet Pond Nantucket MA97055 

Mill Pond Burlington MA92041 

Millvale Reservoir* Haverhill MA84041 

Monponsett Pond Halifax MA62119 

Nabnasset Pond Westford MA84044 

Newfield Pond Chelmsford MA84046 

Lake Nippenicket Bridgewater MA62131 

Noquochoke Lake Dartmouth MA95113; MA95170; 

MA95171 

North Watuppa Lake Fall River MA61004 

Nutting Lake Billerica -2 segments MA82088; MA82124 

Otis Reservoir Otis/Tolland/ Blandford MA31027 

Pentucket Pond* Georgetown MA91010 

Lake Pentucket* Haverhill MA84051 

Peters Pond Sandwich MA96244 

Plainfield Pond Plainfield MA33017 

Pomps Pond* Andover MA83014 

Pontoosuc Lake Lanesborough/Pittsfield MA21083 

Populatic Pond Norfolk MA72096 

Pottapaug Pond Basin Petersham MA36125 

Quabbin Reservoir Petersham/Pelham/Ware 

Hardwick/Shutesbury/Belchertown/New 

Salem 

MA36129 

Quacumquasit Pond Brookfield/E. Brookfield/Sturbridge MA36131 

Rock Pond* Georgetown MA91012 

Lake Rohunta Athol/Orange/New Salem MA35070; MA35106; 

MA35107 

Lake Saltonstall* Haverhill MA84059 

Sheep Pond Brewster MA96289 

Silver Lake Wilmington MA92059 

Snake Pond Sandwich MA96302 

Snipatuit Pond Rochester MA95137 

Somerset Reservoir Somerset MA62174 

Stevens Pond* N. Andover MA84064 

Tom Nevers Pond Nantucket MA97097 
Northeast Regional Mercury TMDL – October 2007 53 

Waterbody Town Segment ID 

Turner Pond New Bedford/Dartmouth MA95151 

Upper Naukeag Lake Ashburnham MA35090 

Upper Reservoir Westminster MA35091 

Wachusett Reservoir Boylston/W.Boylston/Clinton/Sterling MA81146 

Waite Pond Leicester MA51170 

Wakeby Pond Mashpee/Sandwich MA96346 

Walden Pond Concord MA82109 

Lake Wampanoag Ashburnham/Gardner M181151 

Warners Pond Concord MA82110 

Wenham Lake Beverly MA92073 

Wequaquet Lake Barnstable MA96333 

Whitehall Reservoir Hopkington MA82120 

Whiting Pond N. Attleborough/Plainville MA52042 

Wickaboag Pond W. Brookfield MA36166 

Willet Pond Walpole/Westwood/Norwood MA73062 

New Hampshire

The New Hampshire 2006 303(d) list states: “...it is important to note that all surface waters are impaired 

due to fish/shellfish consumption advisories issued because of elevated levels of mercury in fish and 

shellfish tissue. Since mercury is a pollutant that requires a TMDL, all 5000+ surface waters in New 

Hampshire are included on the Section 303(d) List. However, in order to keep the length of the 303(d) 

List in Appendix A to manageable size, surface waters impaired solely by atmospheric mercury 

deposition were not included.” 

Because this TMDL only covers freshwaters, this is applicable to all New Hampshire waters designated 

as RIV, LAK, or IMP, with the exception of waterbodies listed below that are known to have significant 

mercury contributions from more localized sources. Waterbodies designated as EST or OCN are not 

included. 

Waters not covered due to localized sources: 

 Androscoggin River, Berlin 0.350 miles (NHRIV400010605-11) 

 Contoocook River, PWS, WWF, Hopkinton, 0.780 miles (NHRIV700030505-05) 

 Black Brook, Manchester, 2.410 miles (NHRIV700060801-02) 

New York

Based on Final New York State 2006 Section 303(d) List of Impaired Waters Requiring a TMDL/Other 

Strategy 

 Salmon River Reservoir (0303-0069) 

 Susquehanna River, Lower, Main Stem (0603-0016) 

 Susquehanna River, Lower, Main Stem (0603-0015) 

 Susquehanna River, Lower, Main Stem (0603-0013) 

 Susquehanna River, Lower, Main Stem (0603-0002) 

 Susquehanna River, Main Stem (0601-0182) 
Northeast Regional Mercury TMDL – October 2007 54  Susquehanna River, Main Stem (0601-0040)  Susquehanna River, Main Stem (0601-0020)  Goodyear Lake (0601-0015)  Susquehanna River, Upper, Main Stem (0601-0041)  Chenango River, Lower, Main Stem (0602-0033)  Chenango River, Middle, Main Stem (0602-0009)  Chenango River, Upper, Main Stem (0602-0069)  Unadilla River, Lower, Main Stem (0601-0003)  High Falls Pond (0801-0274)  Taylorville, Elmer Falls Ponds (0801-0276)  Effley Falls Reservoir (0801-0172)  Moshier Reservoir (0801-0194)  Sunday Lake (0801-0195)  Soft Maple Reservoir, Soft Maple Pond (0801-0173)  Beaver Lake, Beaver Meadow Pond (0801-0174)  Francis Lake (0801-0192)  Stillwater Reservoir (0801-0184)  Halfmoon Lake (0801-0193)  Dart Lake (0801-0242)  Big Moose Lake (0801-0035)  Lower Sister Lake (0801-0004)  Upper Sister Lake (0801-0008)  Russian Lake (0801-0006)  North Lake (0801-0451)  Forked Lake (0903-0080)  Carry Falls Reservoir (0903-0055)  Tupper Lake (0903-0062)  South Pond (0903-0005)  Lake Eaton (0903-0056)  Indian Lake (0906-0003)  Long Pond (0905-0058)  Cranberry Lake (0905-0007)  Red Lake (0906-0039)  Meacham Lake (0902-0039)  Lake Champlain, Main Lake, North (1000-0001)  Lake Champlain, Main Lake, Middle (1000-0002)  Lake Champlain, Main Lake, South (1000-0003)  Lake Champlain, South Lake (1000-0004)  Lake Champlain, Cumberland Bay (1001-0001)  Saranac River, Franklin Falls Pond (1003-0045)  Middle Saranac Lake/Weller Pond (1003-0083)  Polliwog Pond (1003-0090)  Poultney River, Lower, and tributaries (1005-0053)  Chase Lake, Mud Lake (1104-0135)  Sand Lake (1104-0015)  Spy Lake (1104-0160)  Schroon Lake (1104-0002)  Alder, Crane Ponds (1104-0229)  Kings Flow (1104-0271)  Round Pond (1104-0073)  Rock Pond (1104-0285) 
Northeast Regional Mercury TMDL – October 2007 55 

 Lake Durant (1104-0059) 

 Schoharie Reservoir (1202-0012) 

 Lily, Canada, Stewarts Land, West Lakes (1201-0050) 

 Stoner Lakes (1201-0169) 

 Ferris Lake (1201-0003) 

 Amawalk Reservoir (1302-0044) 

 West Branch Reservoir (1302-0022) 

 Boyd Corners Reservoir (1302-0045) 

 Diverting Reservoir (1302-0046) 

 Bog Brook Reservoir (1302-0041) 

 East Branch Reservoir (1302-0040) 

 Titicus Reservoir (1302-0035) 

 Cross River Reservoir (1302-0005) 

 Breakneck Pond (1301-0123) 

 Chodikes Pond (1301-0208) 

 Rondout Reservoir (1306-0003) 

 Ashokan Reservoir (1307-0004) 

 South Lake, North Lake (1309-0017) 

 Dunham Reservoir (1301-0262) 

 Neversink Reservoir (1402-0009) 

 Loch Sheldrake/Sheldrake Pond (1402-0057) 

 Rio Reservoir (1401-0074) 

 Swinging Bridge Reservoir (1401-0002) 

 Pepacton Reservoir (1403-0002) 

 Cannonsville Reservoir (1404-0001) 

Rhode Island

Based on Final State of Rhode Island 2006 303(d) List of Impaired Waters 

 Indian Lake (RI0008039-02) 

 Watchaug Pond (RI0008039L-02) 

 Meadowbrook Pond (Sandy Pond) (RI0008039L-05) 

 Tucker Pond (RI0008039L-08) 

 Larkin Pond (RI0008039L-11) 

 Hundred Acre Pond (RI0008039L-13) 

 Yawgoo Pond (RI0008039L-15) 

 Alton Pond (RI0008040L-01) 

 Ashville Pond (RI0008040L-04) 

 Wincheck Pond (RI0008040L-06) 

 Yawgoog Pond (RI0008040L-07) 

 Locustville Pond (RI0008040L-10) 

 Wyoming Pond (RI0008040L-11) 

 Browning Mill Pond (Arcadia Pond) (RI0008040L-13) 

 Boone Lake (RI0008040L-14) 

 Eisenhower Lake (RI0008040L-16) 

 Quidneck Reservoir (RI0006013L-04) 

 Tiogue Lake (RI0006014L-02) 

 J.L. Curran Reservoir (Fiskeville Reservoir) (RI0006016L-02) 
Northeast Regional Mercury TMDL – October 2007 56 

Vermont

Based on Final State of Vermont 2006 303(d) List of Impaired Waters 

 Poultney River, Mouth upstream to Carvers Falls (VT02-01) 

 Lower Otter Creek, Mouth Upstream to Vergennes Dam (VT03-01) 

 Little Otter Creek – Lower – From mouth upstream Falls/Ledge West Route 7 (VT03-07) 

 Lower Dead Creek, From Mouth Upstream (VT03-09) 

 Chittenden Reservoir (VT03-14L03) 

 Lake Champlain – Otter Creek Section (VT04-01L01) 

 Lake Champlain – Port Henry Section (VT04-01L02) 

 Lake Champlain – Southern Section (VT04-02L01) 

 Lake Champlain – Missisquoi Bay (VT05-01L01) 

 Lake Champlain – Northeast Arm (VT05-04L01) 

 Lake Champlain – Isle LaMotte (VT05-04L02) 

 Lake Champlain – St. Albans Bay (VT05-07L01) 

 Lake Champlain – Mallets Bay (VT05-09L01) 

 Lake Champlain – Burlington Bay (VT05-10L01) 

 Lake Champlain – Main Section (VT05-10L02) 

 Lake Champlain – Shelburne Bay (VT05-11L01) 

 LaPlatte River, At Mouth (VT05-11) 

 Missisquoi River, Mouth Upstream to Swanton Dam (VT06-01) 

 Lamoille River, Mouth to Clarks Falls Dam (VT07-01) 

 Arrowhead Mountain Lake (VT07-03L03) 

 Winooski River, Mouth to Winooski Dam (VT08-01) 

 Harriman Reservoir (VT12-01L01) 

 Sherman Reservoir (VT12-01L04) 

 East Branch Deerfield River, Below Somerset Dam (VT12-03) 

 Grout Pond (VT12-03L01) 

 Somerset Reservoir (VT12-03L02) 

 Upper Deerfield River, Below Searsburg Dam (VT12-04) 

 Searsburg Reservoir (VT12-04L05) 

 Moore Reservoir (VT16-04L01) 

 Comerford Reservoir (VT16-05L01) 

 Lake Salem (VT17-04L04) 
Northeast Regional Mercury TMDL – October 2007 57 

Appendix B: Necessary Reductions to meet Water Quality Standards in Maine and 

Connecticut

Because this is a regional TMDL and the majority of states have not adopted fish tissue criteria, the 

initial target fish tissue concentration was set at the EPA fish tissue criterion of 0.3 ppm. Maine has 

adopted a fish tissue criterion of 0.2 ppm into their water quality standards, and therefore a higher level 

of reduction will be necessary for water quality standards to be met in that state. Connecticut’s Water 

Quality Standards (2002) state that: 

Surface waters and sediments shall be free from chemical constituents in concentrations or 

combinations which will or can reasonably be expected to: result in acute or chronic toxicity to 

aquatic organisms or otherwise impair the biological integrity of aquatic or marine ecosystems 

outside of any dredged material disposal area or areas designated by the Commissioner for 

disposal or placement of fill materials or any zone of influence allowed by the Commissioner, or 

bioconcentrate or bioaccumulate in tissues of fish, shellfish and other aquatic organisms at levels 

which will impair the health of aquatic organisms or wildlife or result in unacceptable tastes, 

odors or health risks to human consumers of aquatic organisms or wildlife... 

The Connecticut Department of Public Health has set a level of 0.1 ppm in fish tissue as the 

concentration at which there is a risk to humans from consumption of fish. Thus, in order for 

Connecticut’s narrative water quality standards to be met, they must achieve a concentration of 0.1 ppm 

in fish tissue and therefore will need further reductions than set out for the region by this TMDL. 

Necessary reductions to meet water quality standards in Maine and Connecticut are shown below. Both 

of these calculations require reductions in anthropogenic mercury deposition greater than 100 percent. 

However, this number is affected by a number of variables, including the percentage of deposition due to 

anthropogenic sources, and there is a range of accepted values associated with this parameter. Various 

studies have found this percentage to be between 75 and 85 percent. Use of a lower percentage results in 

a greater percent reduction from anthropogenic sources, whereas a higher percentage has the opposite 

effect. 

Because of this uncertainty, adaptive management will be used when implementing the reductions 

necessary to meet the TMDL. 
Northeast Regional Mercury TMDL – October 2007 

Necessary Reductions to Meet Maine Water Quality Standards 

Value (80th percentile) Value (90th percentile) Unit Source 

Background Information Area of the Region (includes CT, MA, ME, NH, NY, RI, VT) 307,890 km2 NESCAUM Proportion of Deposition due to Anthropogenic Sources 0.75 

Based on work by KNorton, et al. 2006 

TMDL Base Year 1998 TMDL Phase I Implementation Period 1998-2003 TMDL Phase II Implementation Period 2003 -2010 TMDL Phase III Implementation Period 2010 on Water Quality Goal Target Fish Mercury Concentration 0.20 ppm Maine Water Quality Existing Level in Fish (32 cm Smallmouth Bass) 0.86 1.14 ppm NERC Dataset Reduction Factor (RF) [(Existing Level - Target Level)/Existing Level] 0.77 0.82 Base Year Loadings Point Source Load (PSL) - Wastewater Discharge 141 kg/yr PCS data Modeled Atmospheric Deposition 5,405 kg/yr 

NESCAUM, based oInventory 

Modeled Natural Atmospheric Deposition1 526 kg/yr 

NESCAUM, based oInventory 

Modeled Anthropogenic Atmospheric Deposition, Anthropogenic Nonpoint Source Load (ANPSL) 4,879 kg/yr 

NESCAUM, based oInventory 

Natural Nonpoint Source Load (NNPSL) Atmospheric Deposition (Based on Deposition is 25% Natural and 75% Anthropogenic) 1,626 kg/yr Kamman and EngstrTotal Nonpoint Source Load (NPSL) [ANPSL + NNPSL] 6,506 kg/yr Total Source Load (TSL) [NPSL + PSL] 6,647 kg/yr 

1 The global contribution to the atmospheric deposition modeling includes some natural sources of mercury. The modeled natural atmo

subtracted from the total modeled atmospheric deposition to avoid double counting of the natural contribution. 
Northeast Regional Mercury TMDL – October 2007 

Percentage of TSL due to PSL 2.1% Loading Goal Loading Goal [TSL x (1-RF)] 1,546 1,166 kg/yr TMDL Wasteload Allocation (WLA) [Keep at 2.1% of TSL] 33 25 kg/yr Load Allocation (LA) [Loading Goal - WLA] 1,513 1,141 kg/yr Natural Load Allocation1 (NLA) 1,626 kg/yr Anthropogenic Load Allocation (ALA) [LA - NLA] -113 -485 kg/yr Overall Reductions to Meet TMDL Necessary In-Region Atmospheric Deposition Reductions to Meet ALA 2,141 2,300 kg/yr Necessary Out-of-Region Atmospheric Deposition Reductions to Meet ALA 2,852 3,064 kg/yr Percent Reduction in Anthropogenic Atmospheric Deposition Necessary to Meet ALA 102.3% 109.9% TMDL Implementation Phase I (50%) In-Region Portion of ANPSL 2,092 kg/yr 

NESCAUM, based oInventory 

In-Region Reduction Target (50% from baseline) 1,046 kg/yr Necessary In-Region Atmospheric Deposition Reductions to meet Phase I Target 1,046 kg/yr In-Region Atmospheric Deposition Reductions Achieved in Phase I 1,549 kg/yr 

NESCAUM, based oemissions inventorie

Remaining In-Region Atmospheric Deposition Reductions Necessary to Meet Phase I Target 0 kg/yr Remaining In-Region Atmospheric Deposition Reductions Necessary to Meet Final TMDL 592 751 kg/yr Out-of-Region Portion of ANPSL 2,787 kg/yr 

NESCAUM, based oInventory 

1 Deposition due to natural sources remains the same over time, so the natural load allocation is equal to the existing natural deposition
Northeast Regional Mercury TMDL – October 2007 

Out-of-Region Reduction Target (50% from baseline) 1,394 kg/yr Necessary Out-of-Region Atmospheric Deposition Reductions to Meet Phase I Target 1,394 kg/yr Additional Out-of-Region Atmospheric Deposition Reductions to Meet Final TMDL 1,458 1,671 kg/yr TMDL Implementation Phase II (75%) In-Region Portion of ANPSL 2,092 kg/yr 

NESCAUM, based oInventory 

In-Region Reduction Target (75% from baseline) 523 kg/yr Necessary In-Region Atmospheric Deposition Reductions to meet Phase II Target 1,569 kg/yr In-Region Atmospheric Deposition Reductions Achieved in Phase I 1,549 kg/yr 

NESCAUM, based oemissions inventorie

Remaining In-Region Atmospheric Deposition Reductions Necessary to Meet Phase II Target 20 kg/yr Remaining In-Region Atmospheric Deposition Reductions Necessary to Meet Final TMDL 572 731 kg/yr Out-of-Region Portion of ANPSL 2,787 kg/yr 

NESCAUM, based oInventory 

Out-of-Region Reduction Target (75% from baseline) 697 kg/yr Necessary Out-of-Region Atmospheric Deposition Reductions to Meet Phase II Target 2,090 kg/yr Additional Out-of-Region Atmospheric Deposition Reductions to Meet Final TMDL 762 974 kg/yr 
Northeast Regional Mercury TMDL – October 2007 

TMDL Implementation Phase III The Phase III timeline and goal will be set following re-evaluation of mercury emissions, deposition, and fish tissue concentrations in 

remaining reductions will be addressed as follows: Major air point sources will be addressed through the application of more stringent 

and/or emission limits, economically and technically feasible/achievable, taking into account advances in the state of air pollution con

transferable technologies used by other sources, to achieve maximum emission reductions. Emissions from area sources will be contr

feasible using Best Management Practices and Pollution Prevention approaches. It should be noted that the goal of this TMDL is to usachieve a target of 0.3 ppm for Massachusetts, New Hampshire, New York, Rhode Island, and Vermont; 0.2 ppm for Maine, and 0.1 papproach will allow all of the Northeast states to meet or exceed their designated uses. 
Northeast Regional Mercury TMDL – October 2007 

Necessary Reductions to Meet Connecticut Water Quality Standards 

Value (80th percentile) Value (90th percentile) Unit Source 

Background Information Area of the Region (includes CT, MA, ME, NH, NY, RI, VT) 307,890 km2 NESCAUM Proportion of Deposition due to Anthropogenic Sources 0.75 

Based on work by KaNorton, et al. 2006 

TMDL Base Year 1998 TMDL Phase I Implementation Period 1998-2003 TMDL Phase II Implementation Period 2003 -2010 TMDL Phase III Implementation Period 2010 on Water Quality Goal Target Fish Mercury Concentration 0.10 ppm Connecticut DepartmExisting Level in Fish (32 cm Smallmouth Bass) 0.86 1.14 ppm NERC Dataset Reduction Factor (RF) [(Existing Level - Target Level)/Existing Level] 0.88 0.91 Base Year Loadings Point Source Load (PSL) - Wastewater Discharge 141 kg/yr PCS data Modeled Atmospheric Deposition 5,405 kg/yr 

NESCAUM, based on Inventory 

Modeled Natural Atmospheric Deposition1 526 kg/yr 

NESCAUM, based on Inventory 

Modeled Anthropogenic Atmospheric Deposition, Anthropogenic Nonpoint Source Load (ANPSL) 4,879 kg/yr 

NESCAUM, based on Inventory 

Natural Nonpoint Source Load (NNPSL) Atmospheric Deposition (Based on Deposition is 25% Natural and 75% Anthropogenic) 1,626 kg/yr Kamman and EngstroTotal Nonpoint Source Load (NPSL) [ANPSL + NNPSL] 6,506 kg/yr Total Source Load (TSL) [NPSL + PSL] 6,647 kg/yr Percentage of TSL due to PSL 2.1% Loading Goal 1 The global contribution to the atmospheric deposition modeling includes some natural sources of mercury. The modeled natural atmo

subtracted from the total modeled atmospheric deposition to avoid double counting of the natural contribution. 
Northeast Regional Mercury TMDL – October 2007 

Loading Goal [TSL x (1-RF)] 773 583 kg/yr TMDL Wasteload Allocation (WLA) [Keep at 2.1% of TSL] 16 12 kg/yr Load Allocation (LA) [Loading Goal - WLA] 756 571 kg/yr Natural Load Allocation1 (NLA) 1,626 1,626 kg/yr Anthropogenic Load Allocation (ALA) [LA - NLA] -870 -1,056 kg/yr Overall Reductions to Meet TMDL Necessary In-Region Atmospheric Deposition Reductions to Meet ALA 2,465 2,545 kg/yr Necessary Out-of-Region Atmospheric Deposition Reductions to Meet ALA 3,284 3,390 kg/yr Percent Reduction in Anthropogenic Atmospheric Deposition Necessary to Meet ALA 117.8% 121.6% TMDL Implementation Phase I (50%) In-Region Portion of ANPSL 2,092 kg/yr 

NESCAUM, based on Inventory 

In-Region Reduction Target (50% from baseline) 1,046 kg/yr Necessary In-Region Atmospheric Deposition Reductions to meet Phase I Target 1,046 kg/yr In-Region Atmospheric Deposition Reductions Achieved 1998-2002 1,549 kg/yr 

NESCAUM, based on emissions inventories 

Remaining In-Region Atmospheric Deposition Reductions Necessary to Meet Phase I Target 0 kg/yr Remaining In-Region Atmospheric Deposition Reductions Necessary to Meet Final TMDL 916 996 kg/yr Out-of-Region Portion of ANPSL 2,787 kg/yr 

NESCAUM, based on Inventory 

Out-of-Region Reduction Target (50% from baseline) 1,394 kg/yr 1 Deposition due to natural sources remains the same over time, so the natural load allocation is equal to the existing natural deposition
Northeast Regional Mercury TMDL – October 2007 

Necessary Out-of-Region Atmospheric Deposition Reductions to Meet Phase I Target 1,394 kg/yr Additional Out-of-Region Atmospheric Deposition Reductions to Meet Final TMDL 1,891 1,997 kg/yr TMDL Implementation Phase II (75%) In-Region Portion of ANPSL 2,092 kg/yr 

NESCAUM, based on Inventory 

In-Region Reduction Target (75% from baseline) 523 kg/yr Necessary In-Region Atmospheric Deposition Reductions to meet Phase II Target 1,569 kg/yr In-Region Atmospheric Deposition Reductions Achieved in Phase I 1,549 kg/yr 

NESCAUM, based on emissions inventories 

Remaining In-Region Atmospheric Deposition Reductions Necessary to Meet Phase II Target 20 kg/yr Remaining In-Region Atmospheric Deposition Reductions Necessary to Meet Final TMDL 896 976 kg/yr Out-of-Region Portion of ANPSL 2,787 kg/yr 

NESCAUM, based on Inventory 

Out-of-Region Reduction Target (75% from baseline) 697 kg/yr Necessary Out-of-Region Atmospheric Deposition Reductions to Meet Phase II Target 2,090 kg/yr Additional Out-of-Region Atmospheric Deposition Reductions to Meet Final TMDL 1,194 1,300 kg/yr 
Northeast Regional Mercury TMDL – October 2007 

TMDL Implementation Phase III The Phase III timeline and goal will be set following re-evaluation of mercury emissions, deposition, and fish tissue concentrations in 

remaining reductions will be addressed as follows: Major air point sources will be addressed through the application of more stringent 

and/or emission limits, economically and technically feasible/achievable, taking into account advances in the state of air pollution con

transferable technologies used by other sources, to achieve maximum emission reductions. Emissions from area sources will be contr

feasible using Best Management Practices and Pollution Prevention approaches. It should be noted that the goal of this TMDL is to uachieve a target of 0.3 ppm for Massachusetts, New Hampshire, New York, Rhode Island, and Vermont; 0.2 ppm for Maine, and 0.1 papproach will allow all of the Northeast states to meet or exceed their designated uses. 
Northeast Regional Mercury TMDL – October 2007 66 

Appendix C: Mean Mercury Concentrations at NPDES-Permitted Facilities Used in 

Calculating the Baseline Point Source Load1

State NPDES ID Facility Name Hg Concentration (ng/l) 

ME ME Vassalboro 4.53 

ME ME0000159 Fraser Paper 2.72 

ME ME0000167 Katahdin Paper Millinocket 1.70 

ME ME0000175 Katahdin Paper (GNP) East 1.60 

ME ME0000256 CMP FLA Mason Sta 019 7.81 

ME ME0000272 CMP FLP Wyman Sta 004 25.60 

ME ME0000639 Holtrachem 16.20 

ME ME0000736 Togus 11.90 

ME ME0001635 MDI Biological 40.40 

ME ME0001830 General Alum 001 13.52 

ME ME0001856 National Starch 0.87 

ME ME0001872 Domtar (GP) 9.9 

ME ME0001937 International Paper 7.07 

ME ME0002003 Lincoln Pulp & Paper 001 10.6 

ME ME0002020 GP Old Town (Ft James) 8.09 

ME ME0002054 Mead Paper Company 13.26 

ME ME0002097 Naval Security Group 12.93 

ME ME0002160 International Paper - Bucksport <2.0 

ME ME0002216 Staley 10.93 

ME ME0002224 American Tissue (Tree Free) 2.20 

ME ME0002321 SD Warren 1.67 

ME ME0002399 First Technology/Control Devices 1.21 

ME ME0002526 Robinson Manufacturing 8.42 

ME ME0020541 Riverwood Health Care 21.90 

ME ME0021521 SD Warren (K) 12.55 

ME ME0022055 Champion (Costigan Stud Mill) 5.76 

ME ME0022519 Gardiner Water District 9.60 

ME ME0022861 Pratt & Whitney 0.72 

ME ME0023043 Penobscot Frozen Foods 11.48 

ME ME0023230 Penobscot Energy Rec. Co. 8.23 

ME ME0023302 University of New England 5.98 

ME ME0023329 Aroostook Valley Electric Co. 67.07 

ME ME0023361 Sunday River Skiway 2.66 

ME ME0023710 Beaverwood 35.92 

ME ME0036218 McCain Processing Inc. 1.97 

ME ME0090000 Downeast Corr. Ctr (Bucks Hbr.) 30.40 

ME ME0090026 U.S. Naval Comm. Sta. (Cutler) 10.80 

ME ME0090051 Winter Harbor Naval Group Act. 15.20 

ME ME0090174 Loring 6.62 

 

1

 The Maine DEP is presently undertaking a review of the mercury effluent data submitted by facilities under its rule 

on Interim Effluent Limitations and Controls for the Discharge of Mercury, 06-096 CMR 519 (effective 

February 5, 2000). This review is validating the submitted data and reviewing the performance trends of particular 

facilities. As such, some of these data may change based on the validation. These changes are not expected to 

affect the overall average concentrations for Maine or the region significantly. 
Northeast Regional Mercury TMDL – October 2007 67 

State NPDES ID Facility Name Hg Concentrations (ng/l) 

ME ME0100013 Augusta 7.66 

ME ME0100021 Bath 10.18 

ME ME0100048 Biddeford 10.01 

ME ME0100056 Bingham 4.47 

ME ME0100064 Boothbay Harbor 33.43 

ME ME0100072 Brewer 1.96 

ME ME0100102 Brunswick 38.81 

ME ME0100111 Bucksport 23.00 

ME ME0100129 Calais 5.86 

ME ME0100137 Camden 14.80 

ME ME0100145 Caribou 10.96 

ME ME0100153 Corinna 6.37 

ME ME0100161 Danforth 8.61 

ME ME0100200 Eastport Main Plant 77.72 

ME ME0100218 Falmouth 8.93 

ME ME0100226 Fort Fairfield 21.03 

ME ME0100242 PWD Gorham (Little Falls) 4.57 

ME ME0100269 Islesboro 1.88 

ME ME0100285 Kittery 5.40 

ME ME0100307 Lisbon 12.82 

ME ME0100315 Livermore Falls 13.41 

ME ME0100323 Machias 7.88 

ME ME0100391 Mechanic Falls 3.34 

ME ME0100404 Milbridge 8.94 

ME ME0100439 Milo 9.02 

ME ME0100447 Newport 3.85 

ME ME0100455 Norway 8.83 

ME ME0100463 Oakland 1.90 

ME ME0100471 Old Town 9.53 

ME ME0100498 Orono 4.52 

ME ME0100501 Dover-Foxcroft 5.28 

ME ME0100528 Pittsfield 3.15 

ME ME0100552 Rumford/Mexico 9.24 

ME ME0100561 Presque Isle 6.01 

ME ME0100587 Richmond 8.00 

ME ME0100595 Rockland 4.31 

ME ME0100609 St. Agatha 3.61 

ME ME0100617 Sanford 1.82 

ME ME0100625 Skowhegan 3.71 

ME ME0100633 South Portland 8.05 

ME ME0100641 Southwest Harbor 15.96 

ME ME0100668 Thomaston 11.17 

ME ME0100684 Van Buren 4.41 

ME ME0100692 Vassalboro (E. Vassalboro) 4.56 

ME ME0100706 Veazie 4.08 

ME ME0100731 Winter Harbor 4.05 

ME ME0100749 Winterport 19.33 
Northeast Regional Mercury TMDL – October 2007 68 

Name NPDES ID Facility Name Hg Concentration (ng/l) 

ME ME0100757 Wiscaset 3.48 

ME ME0100765 Yarmouth 20.91 

ME ME0100781 Bangor 6.90 

ME ME0100790 Wells 10.29 

ME ME0100803 Millinocket 6.70 

ME ME0100820 South Berwick 4.74 

ME ME0100846 Westbrook 6.48 

ME ME0100854 KSTD 5.42 

ME ME0100871 Limerick 8.87 

ME ME0100889 Ellsworth 17.63 

ME ME0100901 Northport Village Corp. 9.68 

ME ME0100935 Kennebunk 11.23 

ME ME0100951 Paris 7.20 

ME ME0100978 Jackman 2.65 

ME ME0100986 Ogunquit 6.06 

ME ME0101028 Washburn 4.83 

ME ME0101036 Freeport 10.02 

ME ME0101061 North Jay 2.13 

ME ME0101079 Mars Hill 3.31 

ME ME0101087 Ashland SD (WOO2697) 5.33 

ME ME0101095 Limestone 6.59 

ME ME0101117 Saco 5.38 

ME ME0101150 Unity 1.52 

ME ME0101176 Bethel 3.38 

ME ME0101184 Kennebunkport 7.23 

ME ME0101192 Castine 7.01 

ME ME0101214 Bar Harbor (Main Plant) 10.62 

ME ME0101222 York 4.91 

ME ME0101231 Blue Hill 7.11 

ME ME0101249 Farmington 35.14 

ME ME0101290 Houlton 2.04 

ME ME0101320 Baileyville 8.64 

ME ME0101338 Mt. Desert Otter Creek 8.33 

ME ME0101346 Mt. Desert Northeast Harbor 6.96 

ME ME0101389 Anson-Madison 3.57 

ME ME0101397 Berwick 2.38 

ME ME0101443 Hartland 4.08 

ME ME0101478 Lewiston/Auburn 6.38 

ME ME0101486 Rumford/Mexico (Rumford Point) 4.05 

ME ME0101516 Great Salt Bay Sanitary District 39.36 

ME ME0101524 Old Orchard Beach 4.32 

ME ME0101532 Belfast 10.84 

ME ME0101621 Farmington MSAD #9 85.60 

ME ME0101664 Bayville Village Corp. 26.14 

ME ME0101681 Madawaska 4.73 

ME ME0101699 Clinton 1.74 

ME ME0101702 Gardner 8.40 
Northeast Regional Mercury TMDL – October 2007 69 

State NPDES ID Facility Name Hg Concentration (ng/l) 

ME ME0101729 Maine Correctional Center 1.54 

ME ME0101788 Howland 2.83 

ME ME0101796 Lincoln 4.62 

ME ME0101800 Telstar High School MSAD #44 49.20 

ME ME0101826 Bonney Eagle MSAD #6 117.00 

ME ME0101842 Sabattus 2.70 

ME ME0101851 Stonington 33.36 

ME ME0101885 North Berwick 4.27 

ME ME0101915 Wilton 16.32 

ME ME0101966 Searsport 18.33 

ME ME0101982 Frenchville 3.64 

ME ME0102016 Lubec 27.29 

ME ME0102032 Guilford/Sangerville 10.21 

ME ME0102059 Scarborough 23.13 

ME ME0102067 Canton 2.57 

ME ME0102075 PWD Portland 10.43 

ME ME0102113 Brunswick Public Works Landfill 5.32 

ME ME0102121 Cape Elizabeth 12.03 

ME ME0102130 Sorrento 8.34 

ME ME0102148 Eastport Quoddy 13.06 

ME ME0102156 East Machais 3.29 

ME ME0102181 Whitneyville 3.40 

ME ME0102237 PWD Peaks Island 16.62 

ME ME0102245 Mattawamkeag 15.90 

ME ME0102253 Warren 13.53 

ME ME0102318 Grand Isle 2.19 

ME ME0102334 Norridgewock 2.08 

ME ME0102351 Skowhegan (River Road) 6.50 

ME ME0102369 Fort Kent 8.56 

ME ME0102377 Sea Meadows 5.53 

ME ME0102431 GSBSD, Damariscotta Mills 7.13 

ME ME0102466 Bar Habor (Hulls Cove) 6.53 

ME ME0102474 Bar Harbor (Degregoire) 8.98 

ME ME0102547 Mt. Desert Somesville 12.19 

ME ME0102555 Mt. Desert Seal Harbor 5.23 

ME ME0102581 Loring Water Treatment Plan 1.60 

ME ME0102652 Vassalboro (N. Main Street) 4.40 

ME ME0102661 Vassalboro (Cemetary Road) 5.45 

ME ME0102741 Biddeford Pool 7.35 

ME MEU500830 Dexter Utility District 10.81 

ME MEU501007 Seal Harbor Sand Filter (MDI) 11.56 

ME MEU501492 St. Andre Health Care 2.48 

ME MEU502345 Skowhegan (River Road) 14.74 

ME MEU503801 Ellsworth (Shore Road) 20.85 

ME MEU506634 Maine Central Railroad 6.34 

ME MEU507044 GSBSD, Damariscotta Mills 9.03 

ME MEU507581 Biddeford Pool 6.42 
Northeast Regional Mercury TMDL – October 2007 70 

State NPDES ID Facility Name Hg Concentration (ng/l) 

ME MEU508101 Vassalboro (N. Main Street) 5.62 

ME MEU508102 Vassalboro (Cemetary Road) 6.39 

MA MA0003905 General Electric Aircraft Eng. 0.20 

MA MA0004341 Wyman-Gordon Company 0.00 

MA MA0004731 Exelon New Boston LLC 3.81 

MA MA0100994 Gardiner WPCF 22.94 

MA MA0103284 MWRA - Deer Island POTW 19.55 

NY NY0021342 Huntington SD 39.00 

NY NY0029351 Kingston 4.00 

NY NY0022403 Little Falls 5.80 

NY NY0030546 LeRoy 2.28 

NY NY0020125 Lowville 0.50 

NY NY0026336 Niagara Falls 32.00 

NY NY0026212 NYC 26th Ward 19.00 

NY NY0026158 NYC Bowery Bay 11.00 

NY NY0026182 NYC Coney Island 9.30 

NY NY0026191 NYC Hunts Point 9.30 

NY NY0026115 NYC Jamaica 46.00 

NY NY0026204 NYC Newtown Creek 34.00 

NY NY0026174 NYC Oakwood Beach 2.70 

NY NY0026166 NYC Owls Head 18.00 

NY NY0026107 NYC Port Richmond 11.00 

NY NY0027073 NYC Red Hook 8.60 

NY NY0026221 NYC Rockaway 14.00 

NY NY0026239 NYC Tallman Island 9.60 

NY NY0026131 NYC Wards Island 7.90 

NY NY0029831 Ogdensburg 1.60 

NY NY0025780 Oneida County SD 1.00 

NY NY0027901 Orange County SD#1 3.70 

NY NY0026255 Poughkeepsie City 41.00 

NY NY0087971 Rensselaer County SD#1 16.00 

NY NY0031895 Rockland County SD#1 64.00 

NY NY0031208 Saugerties 24.00 

NY NY0022748 Suffern 9.80 

NY NY0021750 Suffolk County SD#1 9.40 

NY NY0023311 Suffolk County SD#6 41.00 

NY NY0206644 Suffolk County SD#21 11.00 

NY NY0025984 Watertown 8.70 

NY NY0021610 Webster 2.20 

NY NY0024929 Whitehall 11.60 

NY NY0026689 Yonkers 42.00 

NY NY0068225 Arkema Chemical 37.00 

NY NY0200484 Clean Water Of NY 0.54 

NY NY0072061 CWM 67.13 

NY NY0002275 Honeywell International Inc. 98.00 

NY NY0006670 Nepera 26.93 

NY NY0200867 NYC Staten Island Landfill 37.00 
Northeast Regional Mercury TMDL – October 2007 71 

State NPDES ID Facility Name Hg Concentration (ng/l) 

NY NY0110043 PVS Chemical Solutions, Inc 7.47 

NY NY0000132 Reynolds Metals Company 1.46 

NY NY0005801 Schenectady International - RJ 0.67 

NY NY0000973 West Valley Demonstration Project 12.00 

NY NY0007170 Wyeth Research 0.60 

NY NY0036706 Ticonderoga Village 1.68 

NY NY0004413 Ticond I.P. Mill 11.40 

NY NY0020222 Westport 2.14 

NY Port Henry A 9.37 

NY Port Henry D 9.06 

RI RI0100315 Fields Point 21.00 

RI RI0100072 Bucklin Point 13.00 

VT Shelburne 1 0.96 

VT Shelburne 2 0.51 

VT VT0100358 South Burlington 0.88 

VT VT0100153 Burlington Main 2.06 

VT VT0100226 Burlington N 2.19 

VT VT0100501 Swanton 0.66 

VT St. Albans A 1.77 

VT St. Albans D 1.72 

VT VT0101117 St. Albans Corr 0.32 

VT VT0100404 Vergennes 1.71 

 

Mean 16.64 

Median 7.90 

 

Concentrations shown for each facility are the average of all concentration data available for that facility. 
Northeast Regional Mercury TMDL – October 2007 72 

Appendix D: State Mercury Reduction Plans

All of the Northeast states are committed to mercury reduction and there are a number of written 

documents that describe these efforts. Below is a list of these documents with the web addresses where 

they can be obtained. 

Connecticut

Toward the Virtual Elimination of Mercury from the Solid Waste Stream

http://ct.gov/dep/lib/dep/mercury/gen_info/mercury.pdf 

Maine

Mercury in Maine – A Status Report

http://www.maine.gov/dep/mercury/mercury_in_maine.pdf 

Massachusetts

Massachusetts Zero Mercury Strategy 

http://www.mass.gov/envir/Sustainable/resources/pdf/Resources_Hg_Strategy.pdf 

New Hampshire

New Hampshire Mercury Reduction Strategy 

http://www.des.state.nh.us/NHPPP/merc20.pdf 

New York

New York State Department of Environmental Conservation Mercury Work Group Recommendations to 

Meet the Mercury Challenge 

http://www.dec.ny.gov/docs/permits_ej_operations_pdf/meetmercurychallenge.pdf 

Rhode Island

Final Report of the Rhode Island Commission on Mercury Reduction and Education

http://www.dem.ri.gov/topics/pdf/hgcomrep.pdf 

Vermont

Advisory Committee on Mercury Pollution 2007 Annual Report 

http://www.mercvt.org/acmp/reports/2007_report.pdf 
Northeast Regional Mercury TMDL – October 2007 73 

Appendix E: Response to Comments 

Draft Northeast Regional Mercury TMDL Response to Comments

Prepared by NEIWPCC, CT DEP, ME DEP, MA DEP, NH DES, NYS DEC, RI DEM, VT DEC 

The Northeast States and NEIWPCC received comments from 14 different groups on the draft Northeast 

Regional Mercury TMDL. The draft TMDL was released for public comment on April 11, 2007 with a 

public comment period ending June 8, 2007. The comments received and their responses have been 

organized in accordance with the sections of the draft TMDL. The number at the end of each comment 

corresponds to the list of commenters, which can be found at the end of the document. 

In addition to a number of specific comments on the TMDL, the states and NEIWPCC received many 

comments that were generally supportive of the TMDL effort. The states and NEIWPCC are appreciative 

of the support for this effort. Comments of general support are grouped together and listed at the 

beginning of the document. Supportive comments that pertain to a particular section of the TMDL are 

listed under that section with no response given. All questions and recommendations are listed under the 

corresponding TMDL section with the response below. In some cases, comments are grouped together 

and one response is provided for this group. 

General Support for TMDL

Comments: 

 We hope that EPA views the Northeast Regional TMDL as a unique collaborative effort which 

eliminates the duplication of resources that would have been necessary if each state drafted, and EPA 

reviewed, individual TMDLs. This truly groundbreaking effort should be used as a model of 

cooperation for future similar endeavors1

. 

 The Adirondack Council fully supports the proposed TMDL as presented by the Department of 

Environmental Conservation1

. 

 CCE applauds New York State, as well as the other participating states and the NEIWPCC for 

drafting a plan to reduce mercury in the waters of New York State and New England to eliminate fish 

consumption advisories caused by mercury air deposition2

. 

 The Northeast Environmental Organizations therefore strongly endorse the States’ ultimate goal to 

control all sources of mercury by implementing existing reduction control technologies on upwind 

out-of-region sources3

. 

 I would like to applaud your efforts in taking a concerted approach with other Northeastern States4

. 

 Overall, the Onondaga Nation strongly supports the recommendations of the draft TMDL5

. 

 The Fish and Game department is in support of the regional TMDL approach in reducing mercury in 

the environment6

. 

 The MWRA supports this TMDL, which addresses the most significant source of mercury to 

Massachusetts lakes and ponds: atmospheric deposition. MWRA supports the efforts of the Northeast 
Northeast Regional Mercury TMDL – October 2007 74 

states to require more stringent levels of mercury control in power plants emissions than is achievable 

by CAMR7

. 

 The Northeast Environmental Organizations agree the States have made "nationally significant 

reductions to in-state sources of mercury as a result of their regional action plan." The Mercury 

TMDL is therefore the most effective strategy to reduce the ongoing wide spread mercury 

contamination across the Northeast, and is legally mandated by section 303(d) of the Clean Water 

Act3

. 

 As described in our letter of May 31, we support the efforts of NEIWPCC and the northeast states to 

coordinate in developing an innovative TMDL approach for mercury-impaired waters. With a large 

number of mercury-impaired waters in the region, an approach which can most efficiently address 

those impairments appears to be most appropriate.8

 We look forward to working with NEIWPCC and the northeast states regarding how best to address 

our comments in order to strengthen the TMDL. We would be happy to provide technical advice or 

assistance where appropriate.8

Comments and Responses Organized by Draft TMDL Section

2 Background 

Comment: 

 Multi-state or regional TMDLs are clearly contemplated by EPA under section 303(d) of the Clean 

Water Act to address atmospheric deposition. The need to address the widespread impairment of the 

States’ waters by mercury from upwind out-of-region sources calls for such a multi-state, regional 

approach. The States have undertaken substantial efforts to control mercury loadings from in-state 

sources; the Mercury TMDL demonstrates unequivocally that waters will continue to be impaired for 

mercury, however, as a result of upwind out-of-region emissions. The Clean Water Act provides for 

a regional approach to address precisely this situation; indeed, the States are obligated to submit 

proposed loadings that require reductions from such upwind out-of-region sources3

. 

Comment: 

 Include Connecticut River Fish Tissue Contaminant Study in list of TMDL references9

. 

Response: 

Information from this report will be added to the background information in the TMDL document and

a reference to the study will be added to the list of references. However, it should be noted that the 

data collected as part of the Connecticut River study were not included in the fish tissue dataset used 

for developing the TMDL. The Connecticut River data lacked sufficient georeferencing to be 

included in the NERC dataset that was used for TMDL development. The fish tissue concentrations 

for smallmouth bass and yellow perch measured as part of the Connecticut River study aligned with 

the concentrations found in the NERC dataset. Inclusion of these data in the calculations of the 80th

to 90th percentile existing fish concentration would not have resulted in an appreciable difference in 

the TMDL baseline or targets. 
Northeast Regional Mercury TMDL – October 2007 75 

2.3 Massachusetts TMDL Alternative and EPA Justification for Disapproval 

Comment: 

 EPA's June 21, 2006, response to the TMDL Alternative proposed by Massachusetts in 2004 is 

significant in the context of the Mercury TMDL for the following reasons. First, EPA confirms that 

atmospheric deposition causes a significant portion of the mercury impairment in Massachusetts 

waters. Second, EPA concludes that the fact that Massachusetts has in place an effective and 

comprehensive management plan to address in-state sources of mercury does not remove 

Massachusetts's obligation to submit draft TMDL loadings that address sources beyond its borders. 

Third, EPA acknowledges that other pollution control requirements required under either state or 

federal authority are insufficient to achieve applicable water standards for mercury in Massachusetts. 

As a result, in order to fulfill its TMDL obligations relating to mercury impaired waters, 

Massachusetts must undertake a broader assessment and propose loadings for out-of-state sources. 

As these same obligations apply to the other New England states and New York, EPA's statements 

confirm the validity of the approach taken by the Mercury TMDL3

. 

2.6 Control of In-State Sources not Sufficient to Meet Water Quality Standards 

Comments: 

 We commend New York State, the six New England states, and the New England Interstate Water 

Pollution Control Commission for developing a regional approach to reducing mercury emissions. 

We also commend these states for their efforts to significantly reduce their own mercury emissions - 

beyond what is required by federal law. However, we also recognize that even the crucial planned 

regional actions will not be enough to address the problem of mercury deposition and toxicity in the 

region. The TMDL strategy, in setting targets for reduction both within the region and outside the 

region, demonstrates the need for more aggressive action at the national level - a position that we 

fully endorse10. 

 Agree with the statement and assessment in Section 2.6 that control of in-state sources is not 

sufficient. Northeast states have made very significant mercury reductions in the last decade and 

EPA should be actively supporting our efforts through grants and technical assistance9

. 

3 Applicable Water Quality Standards and Fish Tissue Criteria

Comment: 

 Water quality standards: The TMDL currently does not clearly describe the individual water quality 

standards for mercury for each of the states, except for MA and ME, and whether the states have 

water column criteria. As one of the key elements of a TMDL, it is important that the regional 

TMDL describe for each state its mercury criteria, both water column and fish tissue. Where 

appropriate, the TMDL should indicate that a state is using narrative criteria to select a fish tissue 

criterion based on consumption advisories, and provide the state’s rationale for such an interpretation. 

In addition, the TMDL should demonstrate that meeting the fish tissue criterion also assures that the 

water column criterion is met in each state8

. 

Response: 

Table 3-1 of the TMDL will be revised to include each state’s water column criteria for mercury. 

Calculations will also be shown to demonstrate that meeting fish tissue criteria will ensure that water 

column criteria are met. Because fish tissue criteria account for bioaccumulation, they are more 

protective than using water column concentrations. In Connecticut, the fish tissue concentration is 
Northeast Regional Mercury TMDL – October 2007 76 

not a criterion that is part of the state water quality standards, but the water quality standards 

contain a narrative standard for protection of human health that relies on the Department of Public 

Health’s fish tissue guidance value and fish consumption advisories. The language of the narrative 

criteria is provided in Appendix B of the TMDL. 

4.1 Fish Tissue Monitoring Dataset 

Comment: 

 We support the use of the NERC dataset as appropriate for the development of the draft TMDL3

. 

Comment: 

 Fish Tissue Data: We recommend that the TMDL provide additional information on the rationale for 

using smallmouth bass to calculate the necessary reductions in mercury loadings for the region. The

TMDL indicates in Table 4-1 that there is data showing that the concentrations in smallmouth bass 

are highest. The TMDL should describe what data is available on each species, numbers of samples, 

and how that data is distributed geographically across the states. The purpose of such information is 

to demonstrate that there is sufficient fish tissue data coverage for the entire region, such that it is 

reasonable to use the 80th-90th smallmouth bass fish tissue concentration as representative of all seven 

states8

. 

Response: 

 The regional fish tissue dataset that was used in the TMDL analysis contained 867 datapoints for 

 largemouth bass, 342 datapoints for smallmouth bass, 71 datapoints for walleye, and 2,527 

 datapoints for yellow perch. Smallmouth bass was selected as the target species because it was the 

 species with the highest mercury concentration for which there were a reasonable number of 

 datapoints available. We did not feel that there was a sufficient number of walleye datapoints and use 

 of largemouth bass or yellow perch would have resulted in a less protective TMDL. 

4.2 Areas of Elevated Concentration 

Comments: 

 We recommend that the plan explicitly recognize that areas of elevated concentration can result from 

a combination of greater sensitivity, due to local and upstream factors such as acidification and the 

presence of conditions that promote the formation of methylmercury, and greater local or upstream 

deposition. We also strongly recommend that the plan call for appropriate, and spatially specific 

reductions in mercury deposition to address these specific problematic conditions, not only locally but 

upstream within the watersheds of these areas of elevated concentration10. 

 Plans to meet the TMDL goals should take into account the varying susceptibility of different 

locations to mercury deposition and the varying vulnerability of different species and ecosystems to 

the formation and biological accumulation of methlymercury. We recommend that the plan develop 

stringent goals for reducing exposure of mercury among these most vulnerable species and 

ecosystems10. 

Response: 

Because some areas and species are more sensitive to mercury pollution, these areas and species may 

also be more sensitive to reductions in mercury emissions and deposition. Therefore, these areas and 

species may actually respond more quickly to decreases in mercury deposition. However, the exact 
Northeast Regional Mercury TMDL – October 2007 77 

response of these areas and species is not known. Therefore, these areas are targeted to be more 

closely monitored during the TMDL implementation period. If monitoring results indicate that more 

specific reduction strategies are necessary for these areas and species, they will be implemented at 

that time. The adaptive implementation approach will allow for changes in the approach to 

addressing sensitive areas if necessary. Although the necessary reductions are not known for nonfish species, implementation of the TMDL should result in significant reductions for these species. In 

addition, for this TMDL a high trophic level predator was chosen as the target species and use of 80th

– 90th percentile size adjusted values provides a margin of safety. So, while exact calculations for 

these species are outside the scope of this TMDL, implementation of the TMDL will have beneficial 

effects for these species. 

Some areas that have been identified to have high local deposition, such as Southeast New 

Hampshire/Northeast Massachusetts are already being addressed through strict reductions targets on 

nearby coal-fired power plants, municipal waste combustors, and medical waste incinerators. It is 

expected that these existing controls, in conjunction with more stringent controls on out-of-region 

sources, will result in these areas meeting the fish tissue target concentration. Re-evaluation of the 

TMDL at the end of Phase II will allow for further reductions to be implemented if necessary. 

Comment: 

 The states need to consider the potential for confounding variables that shift the reduction burdens 

assigned in the Regional TMDL11. 

Response: 

There are a number of factors that contribute to mercury accumulation in waterbodies in addition to 

the actual mercury deposition. However, many of these factors cannot be controlled. Some 

watersheds are naturally more sensitive due to geology and prevalence of wetlands. 

Nutrients are another factor which generally affect mercury accumulation, and higher nutrient levels 

are normally associated with lower fish mercury levels. While there is potential to control nutrient 

levels, states are generally working toward achieving lower nutrient levels to improve dissolved 

oxygen for aquatic life and reduce the risk of algal blooms. This enhances the need for meaningful 

mercury controls to meet the multiple uses of waters that need to meet recreational, aquatic life, and 

fish consumption uses. 

Because specific areas have been identified as more sensitive to mercury pollution, including 

impoundments subject to hydropower modification, these areas will be more closely monitored 

during the implementation of the TMDL. The adaptive implementation approach of the TMDL, as 

well as existing licenses for hydropower storage impoundments that require monitoring for mercury 

impacts on wildlife, will allow for changes in the approach to addressing sensitive areas if necessary 

and will allow for refinements as scientific data and understanding evolve. 

Comment: 

 In particular, Section 4.2 indicates that there are areas of elevated fish tissue mercury concentrations, 

and that these areas will respond differently than other areas. However, only one area in MA is 

excluded from the TMDL. The TMDL should indicate whether these areas of higher sensitivity will 

attain the TMDL target; if not, we recommend that the states consider addressing these areas 

separately from the rest of the TMDL (e.g., a separate TMDL calculation) or excluded from the 

TMDL, similar to the areas in MA8

. 
Northeast Regional Mercury TMDL – October 2007 78 

Response:

Because some areas are more sensitive to mercury pollution due to factors such as water chemistry, 

presence of wetlands, and water level fluctuations, these areas may also be more sensitive to 

reductions in mercury emissions and deposition. Therefore, these areas may actually respond more 

quickly to decreases in mercury deposition. However, the exact response of these areas is not known. 

Therefore, these areas are targeted to be more closely monitored during the TMDL implementation 

period. If monitoring results indicate that more specific reduction strategies are necessary for these 

areas, they will be implemented at that time. The adaptive implementation approach will allow for 

changes in the approach to addressing sensitive areas if necessary. 

5 Northeast Regional Approach

Comment: 

 At the same time, the TMDL should provide further information regarding the basis for a single 

TMDL encompassing waterbodies in seven states, and how the TMDL will achieve water quality 

standards in each of the states. The TMDL mentions air deposition of mercury as the reason for 

taking a regional approach. The TMDL would be strengthened if it described why all of the 

waterbodies identified in the draft TMDL can be treated similarly for the purposes of a TMDL. 

Specifically, the TMDL should provide further details on factors in support of the regional approach, 

including the geographic distribution of sources, both point sources and nonpoint sources (air 

deposition), land use, and fish mercury levels, and identify any geographic variation in these factors. 

If there isn't adequate justification for the single region approach, we recommend breaking the TMDL 

into appropriate sub-regions, or separating out any waters/areas that may be unlikely to achieve the 

fish tissue target with the reductions called for in the proposed regional TMDL8

. 

Response: 

Because the entire region is impacted by local, regional, and global mercury deposition sources, the 

Northeast states and NEIWPCC feel that it is appropriate to keep the TMDL at the scale of the entire 

region. By targeting fish tissue concentrations, the TMDL ensures that water quality standards for 

mercury in the water column will be met. Calculations in the revised TMDL will demonstrate the 

relationship between water column concentrations and fish tissue concentrations and that the fish 

tissue concentration is more protective. For Connecticut, meeting the 0.1 ppm guidance value used 

by the Department of Public Health ensures the state’s narrative criteria for protection of human 

health are met. 

Kamman, et al. (2005) provides that although there are differences in fish tissue concentrations 

across states, differences in fish tissue concentrations are more strongly influenced by individual fish 

length than they are by jurisdiction. In the case of smallmouth bass, once the effect of length is 

accounted for, there is very little variation in fish concentrations among the states. This relationship 

can be seen in a graph that has been added to the revised TMDL. 

5.1 Impaired Waters

Comments: 

 Waterbodies Covered by the TMDL: It is important to identify each waterbody as it appears on the 

state’s 303(d) list or Integrated Report. This could be done by providing a link between the 

waterbodies addressed by the TMDL and the category 5 listings, i.e., which 303(d) list/integrated 

report year is being addressed (e.g., 2006) and which impairments are being addressed. The TMDL 

should also indicate the priority ranking for waterbodies being addressed in the TMDL8

. 
Northeast Regional Mercury TMDL – October 2007 79 

 In addition, if the TMDL covers some but not all the waters on a state’s 303(d) list or integrated 

report, we recommend that the waters be described so it is clear which waters are covered. In 

particular, it would be helpful if the TMDL clarified both in Table 5-1 and Appendix A for CT, ME, 

and NH how the excluded waters are designated in each state’s integrated list. For example, in 

Maine, are the waters in the category “estuarine and marine” waters excluded, and in CT, are the 

waters designated “E” excluded from the TMDL8

? 

 Pollutant Sources – Air Deposition: The TMDL indicates that it applies only to waterbodies impaired 

for mercury primarily from air deposition. We recommend the TMDL explain the process for 

determining that the waters covered by the TMDL are waters impaired primarily by air deposition, 

especially for the three states for which all waters are included in the TMDL8

. 

Response: 

For Massachusetts, New York, Rhode Island, and Vermont, the waters listed in Appendix A of the 

TMDL were taken directly from the states’ most recently approved 303(d) or Integrated List. The 

revised TMDL will explicitly state the year of the report that is being referenced. For Connecticut, 

Maine and New Hampshire, the TMDL applies to all fresh waterbodies with the exception of a small 

number of waterbodies that will be listed in the revised TMDL. These are waterbodies where 

atmospheric deposition is not the primary source of mercury pollution. In Connecticut, this means all 

waterbodies that are not designated with an “E” (for estuary). For New Hampshire, this means any 

waterbodies that are designated as RIV (river), LAK (lake), or IMP (impoundment). Waterbodies 

designated EST (estuary) and OCN (ocean) are not included. For Maine, waterbodies designated as 

rivers, streams, and lakes are included. Those designated as marine and estuarine are not included. 

Connecticut’s Integrated List provides the following language: 

“In addition to those waters included on the list, all waterbodies where statewide fish 

consumption advisories have been established due to atmospheric deposition of mercury from sources 

outside of state jurisdictional borders are implicitly included in EPA Category 5 ("303(d) listed"). 

Specific fish consumption advisories established as a result of local pollution sources (i.e. releases of 

polychlorinated biphenyls - PCBs or chlordane) are individually listed in Appendix C-4.” 

Maine DEP lists waters impaired by atmospheric deposition of mercury in Category 5C: 

“Category 5-C: Waters Impaired by Atmospheric Deposition of Mercury. Regional or National 

TMDL may be Required. 

5-C: Impairment caused by atmospheric deposition of mercury and a regional scale TMDL is 

required. Maine has a fish consumption advisory for fish taken from all freshwaters due to mercury. 

Many waters, and many fish from any given water, do not exceed the action level for mercury. 

However, because it is impossible for someone consuming a fish to know whether the mercury level 

exceeds the action level, the Maine Department of Human Services decided to establish a statewide 

advisory for all freshwater fish that recommends limits on consumption. Maine has already instituted 

statewide programs for removal and reduction of mercury sources. The State of Maine is 

participating in the development of regional scale TMDLs for the control of mercury.” 

The New Hampshire 303(d) list states: 

“..it is important to note that all surface waters are impaired due to statewide fish/shellfish 

consumption advisories issued because of elevated levels of mercury in fish and shellfish tissue. 

Since mercury is a pollutant that requires a TMDL, all 5000+ surface waters in New Hampshire are 

included on the Section 303(d) List. However, in order to keep the length of the 303(d) List in 

Appendix A to manageable size, surface waters impaired solely by atmospheric mercury deposition 

were not included.” 
Northeast Regional Mercury TMDL – October 2007 80 

Therefore, all fresh waterbodies in Connecticut, Maine, and New Hampshire with the exception of 

those listed in Appendix B of the revised TMDL are included in the Northeast Regional TMDL. 

Comment: 

 Future listings: The draft TMDL indicates that future mercury listings would be covered by the 

TMDL. It would be helpful if the TMDL clarified how such future listings would be covered through 

the listing process, and how the states would provide for adequate public comment8

.

Response: 

This TMDL applies to the impaired waterbodies that are listed in Appendix A of the TMDL document. 

This TMDL may, in appropriate circumstances, also apply to waterbodies that are listed for mercury 

impairment in subsequent state CWA § 303(d) Integrated List of Waters. For such waterbodies, this 

TMDL may apply if, after listing the waters for mercury impairment and taking into account all 

relevant comments submitted on the CWA § 303(d) list, the state determines with EPA approval of the 

CWA § 303(d) list that this TMDL should apply to future mercury impaired waterbodies. 

5.2 Selection of Existing Fish Mercury Concentration Based on Standard Size Fish 

Comment: 

 Agree with choice of basing TMDL analysis on 80th and 90th percentile of distribution of standard 

length fish because it is more protective9

. 

Comment: 

 We also recommend that the TMDL describe how using a range of 80th-90th percentile fish tissue 

concentrations is adequately protective. Would waters where fish tissue levels are above the 90th

percentile meet the TMDL target, or, if not, how will they be addressed (would they potentially need 

to be excluded and addressed separately)? What is the rationale for providing a range, rather than just 

the 90th (or 80th) percentile8

? 

Response: 

The figure below shows the cumulative distribution of length-standardized smallmouth bass mercury 

concentrations based on data within the NERC dataset, in comparison to those for all fish species. 

Smallmouth bass was selected as the standard indicator target species for this TMDL because its use 

balances the competing needs of having a sufficient quantity of fish-mercury datapoints and a 

sufficiently high-mercury fish to provide a strongly protective TMDL. The 80th percentile value of 

0.86 ppm mercury for smallmouth bass corresponds to the 90th percentile concentration for all fish 

species, while the 90th percentile value of 1.14 ppm mercury for smallmouth bass corresponds to the

96th percentile concentration for all fish species. As such, by targeting the range of smallmouth bass 

concentrations shown in the TMDL calculations, we are ensuring that fully 96 percent of fish should 

ultimately come into compliance with water quality standards. The graph shown below will be added 

to the revised TMDL.
Northeast Regional Mercury TMDL – October 2007 81 

Cumulative Distribution of Mercury Concentrations in Northeast Fish 

Total mercury in fillets (ppm wet weight)

0.1 1

Cumulative % of observations

0

20

40

60

80

100

All species 80th %ile = 0.68, 90th %ile = 0.91

Smallmouth bass 80th %ile = 0.86, 90th %ile = 1.12 

5.3 Target Fish Mercury Concentration 

Comment: 

 The draft TMDL's adoption of EPA's methylmercury fish tissue criterion of 0.3 ppm as the common 

endpoint is reasonable. Four of the States have adopted a fish tissue concentration 0.3 ppm as the 

basis for fish consumption advisories, and others have stricter requirements. Given the well 

documented human health impacts of mercury consumption, the Northeast Environmental 

Organizations encourage each state to adopt the most stringent standard practicable when evaluating 

the endpoint TMDL levels in 2010, as called for in the Mercury TMDL3

. 

Comment: 

 The Northeast Regional Mercury TMDL should use a more stringent mercury fish tissue target of 0.1 

ppm. CCE recommends that the more protective standard of 0.1 ppm which is already being utilized 

in Connecticut, be used in New York and the other Northeast states2

. 

Response: 

States consider a number of factors and sources of data when determining a target fish tissue 

concentration and do not base fish consumption advisory decisions solely on guidance 

concentrations. There is currently no risk-assessment basis for regionwide adoption of a 0.1 ppm 

criterion. A region-wide target of 0.3 ppm is viewed as a reasonable initial goal. 

Comment: 

 The TMDL should be revised to expressly state that NY will change its guidance values from 1.0 

ppm to 0.3 ppm5

. 
Northeast Regional Mercury TMDL – October 2007 82 

Response: 

New York cannot commit to changing its guidance value at this time. There are a number of 

factors in addition to the guidance value that states consider when making decisions about fish 

consumption advisories, so New York’s use of 1.0 ppm does not mean that fish consumption 

advisories are not issued unless this value is exceeded. 

Comment: 

 We believe that a more technically sound approach [for setting the fish tissue target] would be to 

consider the data from all of the relevant fish species. This would be consistent with the approach 

outlined in EPA's "Draft Guidance for Implementing the January 2001 Methlymercury Water Quality 

Criterion." That document states that "[if target populations consume fish from different trophic 

levels, the state or authorized tribe should consider factoring the consumption by trophic levels when 

computing the average methylmercury concentration in fish tissue." The agencies should revise the 

TMDL to implement that recommendation. By taking into account what fish people actually 

consume, the agencies would be developing a TMDL that is more grounded in facts and is more 

likely to focus on preventing real risks12. 

Response: 

Not all of the states have the data available to show which types of fish their residents are 

consuming. These are very likely to differ across the region, by population and with time. By using a 

high trophic level species with a high concentration, a conservative approach is being used that will 

protect both general and sensitive populations. This ensures that the highest level consumers will be 

protected and allows for a margin of safety to be built into the TMDL. Moreover, fish that feed high 

on the food web, such as smallmouth bass, are more reflective of other obligate apex predators such 

as loons and eagles. By targeting the TMDL to 80th to 90th percentile smallmouth bass(which is the 

equivalent of 90th to 96th percentile of all fish), ecological health as well as human health are 

protected by ensuring that the prey upon which obligate piscivores feed will have low enough 

mercury concentrations to preclude risk to the most mercury-sensitive aquatic biota. 

Comment: 

 The states cannot develop and apply an ad hoc water quality criterion without the procedural 

safeguards of notice-and-comment rulemaking followed by EPA review and approval11. 

Response: 

TMDLs are not only based on failure to meet water quality criteria, but also on impairment of a 

designated use. Because the necessity of fish consumption advisories indicates that the affected 

waterbodies are impaired for their designated use of fish consumption, a TMDL is necessary for these 

waters. In the case of mercury, the concentrations used to make decisions about fish consumption 

advisories are the appropriate criteria for deciding if a TMDL is necessary and as a goal for 

restoring the waterbodies to the point where the designated use is met. 

While not all of the states have adopted fish tissue criteria, all of the states have adopted either fish 

tissue criteria or water column criteria. Because the fish tissue criterion accounts for 

bioaccumulation, it is actually more protective than the water column concentration and meeting the 

fish tissue concentration ensures that the water column concentration will be met. 

Comment: 

 TMDL target: The draft TMDL states that the target of 0.3 mg/kg was chosen because it is EPA’s 

recommended criterion. Nonetheless, the TMDL should describe why this target is appropriate for 

the entire region, and how the target assures that each state’s water quality standards will be attained. 
Northeast Regional Mercury TMDL – October 2007 83 

In addition, the TMDL also recognizes that this target is not appropriate for CT and ME, and that the 

proposed TMDL would not attain water quality standards in those states. Appendix B generally 

describes the reductions that would be needed in CT and ME. EPA suggests that it may be more 

appropriate for CT and ME to adopt a TMDL based on Appendix B, rather than the regional TMDL. 

If so, we recommend that the final TMDL submission indicate specifically what TMDL elements, 

including the wasteload and load allocation, are being adopted for these two states8

.

Response:

To more clearly document that the final goal of this TMDL is for Maine and Connecticut criteria to 

 be met, the document will highlight the necessary reductions to meet water quality standards in Maine 

 and Connecticut. In both of those states, calculations require reductions in anthropogenic mercury 

 deposition greater than 100 percent. The calculation of needed reductions is affected by a number of 

 variables, including the percentage of deposition due to anthropogenic sources, and there is a range 

 of accepted values associated with this parameter. Various studies have found this percentage to be 

 between 75 and 85 percent. Use of a lower percentage results in a greater percent reduction from 

 anthropogenic sources, whereas a higher percentage has the opposite effect. Because of these ranges 

 and other reasonable and prudent assumptions made about values for a number of parameters, 

 adaptive management will be used when implementing the reductions necessary to meet the TMDL. At 

 the end of Phase III, the states will re-evaluate progress made toward the 0.2 and 0.1 goals and will 

 determine if adjustments need to be made in the ultimate goals that have been set, or how they can be 

 achieved. 

As is discussed in greater detail in Section 7.6 below, because the entire region is impacted by local, 

regional, and global mercury deposition sources, the Northeast states and NEIWPCC feel that it 

is appropriate to keep the TMDL at the scale of the entire region. 

5.4 Proportionality of Mercury Reductions 

Comment: 

 There is broad support for the assumption set forth in the Mercury TMDL that a decrease in 

atmospheric mercury emissions will result in a proportional decrease in mercury deposition in the 

Northeast, and corresponding decrease in mercury concentrations in fish living in the States’ 

waterbodies. No less an authority than EPA has confirmed the accuracy of this assumption in its 

Mercury Maps model3

. 

Comment: 

 The states' assumption of proportionality is not borne out by the data11. 

Response: 

The assumption of proportionality is based on the results of two models that were presented in the 

U.S. EPA Mercury Maps report. The Mercury Cycling Model and the IEM-2M Watershed Model 

assumed linear relationships between atmospheric deposition and fish tissue mercury concentrations, 

which support the assumption of proportionality. Reductions in fish tissue may not be proportional to 

deposition reductions in the short term, but it is expected that over the long term, when the system 

reaches steady state, a proportional relationship will be observed. Because the relationship may not 

be perfectly linear, the states have chosen to use an adaptive implementation method that will include 

monitoring of mercury emissions, deposition, and fish tissue data, and allow for revising of goals if 

the relationship between reductions in emissions, deposition, and fish tissue concentrations does not 

follow that of the assumptions made in the TMDL. 
Northeast Regional Mercury TMDL – October 2007 84 

Comment: 

 Loading capacity and critical conditions: The TMDL should provide additional information on its 

key assumptions in determining the loading capacity, as well as any other assumptions used in 

developing the TMDL. For example, what assumptions were made regarding how much of the air 

deposition load to land is ultimately delivered to waterbodies? We also recommend that the TMDL 

include an additional justification for using the principle of proportionality to determine the necessary 

reductions in mercury loading. Although assumptions such as proportionality have been used in other 

mercury TMDLs, the northeast TMDL should provide its own support for the assumptions8

. 

Response: 

 At this time, there is no precise modeling of the link between emissions and mercury 

 bioaccumulation or the effect of a given emissions reduction on fish tissue concentrations. 

 Therefore it is reasonable to rely on certain assumptions regarding the relationships between 

 mercury emissions, deposition, and fish tissue concentrations. There is sufficient empirical evidence 

 to show that emissions reductions cause reductions in fish tissue concentrations, which validates the 

 assumptions used in this TMDL. 

 Steady state in environmental systems means that concentrations may vary season to season or even 

 year to year, but that long term averages are constant. The steady state formulation of the Mercury 

 Cycling Model (MCM) shows a linear relationship between concentration in fish and atmospheric 

 deposition rate. The steady state formulation of the IEM-2M model shows that given a decrease in 

 mercury air deposition loading rate, the same decrease is seen in total soil mercury concentration, 

 total water column mercury concentration, and predatory fish mercury concentration. Based on the 

 steady state formulations of the MCM and IEM-2M models, a simplified model can be derived to 

 relate percent reductions in air deposition load to percent reductions in fish tissue concentrations at 

 steady state. 

 The standard steady state bioaccumulation equation is: 

C Cwater

BAF fish t t1 1

= •

 where Cfisht1 and Cwatert1 are methylmercury contaminant levels in fish and water at time t1, 

 respectively and BAF is the site specific bioaccumulation factor, which is constant for a given 

 age/length and species of fish in a specific waterbody 

 For a future time, t2, when mercury concentrations have changed but all other parameters remain 

 constant, the equation can be written as: 

C Cwater

BAF fish t t 2 2

= •

 where Cfisht2 and Cwatert2 are methylmercury contaminant levels in fish and water at time t2, 

 respectively and Cfisht2 is for a fish that is the same age, length, and species as for Cfisht1. 

 Combining the equations produces: 

C

C

C

C

water

water

fish

fish

t

t

t

t

2

1

2

1 =
Northeast Regional Mercury TMDL – October 2007 85 

 Because methylmercury water column concentrations are proportional to mercury air deposition load 

 to a watershed, this equation can be rewritten as: 

L

L

C

C

air

air

fish

fish

t

t

t

t

2

1

2

1 =

 where L airt1 and Lairt2 are the air deposition mercury loads to a waterbody at time t1 and t2, 

 respectively. 

 Based on this relationship, mercury fish concentrations will be reduced from current levels in 

 proportion to load reductions for the watershed. For waterbodies in which air deposition is the only 

 significant source, fish tissue mercury concentration reductions will be directly proportional to air 

 deposition reductions. 

 Because these relationships are based on steady states, we do not expect that a proportional 

 relationship between atmospheric deposition reductions and fish tissue reductions will be observed 

 immediately. However, it is expected this response will be seen over the long term, once systems have 

 reached steady state. While it is acknowledged that there is a time lag between mercury being 

 deposited on land and that mercury reaching waterbodies, it is assumed that the terrestrial system 

 will eventually reach a new steady state with atmospheric deposition, and total loading of mercury to 

 surface water will be proportional to atmospheric deposition. 

6.1 Northeast States Emissions Inventory 

Comment: 

 The Mercury TMDL properly relies on the studies prepared by NESCAUM to inventory mercury 

emissions in the northeastern states3

. 

6.2 Atmospheric Deposition Modeling 

Comment: 

 The Mercury TMDL correctly analyzes the approximate relative contributions from in-state sources 

and upwind out-of-region sources to atmospheric mercury deposition in the States, relying on 

modeling by NESCAUM3

. 

Comment: 

 In Section 6.2, considering adding a graph similar to Figure 6-1 that incorporates data from Table 1 of 

the Mercury Matters report9

. 

Response: 

A graph showing the contributions of different sources to national mercury emissions will be added to 

the revised TMDL. 
Northeast Regional Mercury TMDL – October 2007 86 

6.3 Point Sources to Water 

Comments: 

 Pollutant Sources – Point Sources: We recommend that the TMDL identify the specific NPDESpermitted point sources covered by the TMDL, including NPDES-permitted stormwater sources. 

The TMDL generally mentions categories of sources: POTWs, pulp and paper mills, lighting 

manufacturing, chemical and metal industries as the sources within the region and provides a list of 

categories of mercury sources in the New England Region. In particular, the regional approach would 

be better supported by showing the geographic distribution of sources within the region, and whether 

there are any state or local differences in sources that should be given special consideration or treated 

separately from other areas of the region. For example, Table 6-3 shows much higher mean and 

median concentrations for facilities in Rhode Island than in other states. We recommend that the 

TMDL explain the higher loadings from these facilities, and if appropriate, take such higher loadings 

into account in calculating the total source load, or consider treating these facilities separately8

. 

 We also note that using a median concentration in wastewater treatment plants doesn’t seem to fully 

account for other types of sources that may have much higher mercury concentrations in their 

discharges. If available, we recommend using facility-specific data, or estimates for source 

categories other than wastewater treatment plants, to better characterize the total loadings from point 

sources8

. 

 Baseline total source load: The TMDL establishes a 1998 total source load based on loadings from 

wastewater treatment facilities. It would strengthen the TMDL if it were further explained why 1998 

is an appropriate baseline. We also suggest that the states consider other types of facilities (e.g., pulp 

and paper mills, chloralkali facilities, MS4s) that may have a different mercury concentration in their 

effluent from POTWs. If appropriate, the TMDL should indicate how loadings from sources other 

than wastewater treatment plants are accounted for in the baseline loading estimate8

. 

 The average concentration of mercury in point sources has an enormous variance among states. An 

explanation of the sources of this variance would be helpful and would bolster the credibility of the 

analysis. An explanation of how non-detects were handled in the calculation of average concentration 

would also be helpful7

. 

Response: 

The median wastewater concentration used in the development of the point source load was based on 

data from both wastewater treatment facilities and various types of industrial dischargers. This may 

not be clearly discussed in the draft TMDL, so it will be better described in the revised TMDL. 

It has been determined that data from Rhode Island were collected using EPA Method 245.1 and 

many samples were actually below the detection limit, but reported as the detection limit. The 

detection limit for this method is much higher than the newer EPA Method 1631. The states decided 

that it was not appropriate to use data collected with the older method and therefore these data will 

be excluded and the point source load revised. Rhode Island has a small amount of data that was 

collected under the older method, but the facilities were able to achieve a method detection limit 

much lower than the typical limit for this method. These data will be included in the calculation of 

the point source load. It was also determined that Connecticut’s data were collected using EPA 

Method 245.1, so these data will be excluded and the point source load revised. 
Northeast Regional Mercury TMDL – October 2007 87 

7.5 Wasteload Allocation 

Comments: 

 MWRA agrees that "implementation of mercury minimization plans will help assure that discharges 

have no reasonable potential to cause or contribute to an exceedance of water quality standards7

." 

 MWRA believes that aerial deposition is the largest remaining source of its mercury loadings, both 

within its collection system, and in its receiving waters. MWRA is therefore strongly in favor of the 

goals of the proposed TMDL7

. 

 We agree that an MMP is an appropriate mechanism for addressing point source mercury discharges, 

and we support use of that regulatory tool in the TMDL instead of source-specific allocations or 

numeric permit limits12. 

 We agree with the conclusions in the draft regional TMDL that classify in-state point source 

contributions to waterways as de minimis, and the necessity of controlling sources of atmospheric 

deposition of mercury to waterbodies of the States3

. 

Comment: 

 Definition of de minimis: The TMDL establishes the WLA at 1.2% and indicates this is “de 

minimis.” Using “de minimis” in this context may imply incorrectly that the point sources are not 

subject to any reductions. Thus, we recommend that the term “de minimis” not be used to describe 

the WLA. Alternatively, the TMDL should explain that the term does not imply that point sources 

are not subject to reductions under the wasteload allocation. It would also be helpful if the TMDL 

further explained why 1.2% was selected as the WLA, especially as this is higher than the WLA in 

other approved mercury TMDLs8

. 

Response: 

Upon re-evaluation of the point source load and wasteload allocation, a units error was discovered, 

resulting in the point source load increasing from 1.2 percent to 2.1 percent of the total load. 

However, the states still feel that 2.1 percent is insignificant, and therefore can be considered de 

minimis. As such, we feel that if the point source load is to remain de minimis in the final TMDL, it is 

appropriate to keep it as the same percentage of the TMDL as the percentage of the baseline 

loadings. 

Comment: 

 Implementation of WLA in permits: The TMDL indicates that the WLA will not be allocated among 

sources, but rather through mercury minimization plans and region-wide mercury reduction efforts. 

We recommend that the TMDL clarify how individual permits will be written on the basis of a single 

regional WLA, and how will the allocations be made among the states? We also recommend that the 

TMDL further describe how will it be determined that the WLA will not be exceeded, and how it will 

be determined that there will not be localized exceedance of the water quality standards (e.g., the 

TMDL could indicate that reasonable potential determinations would be made at the time of permit 

issuance)8

Response:

 This TMDL places much emphasis on the fact that the States have agreed to a goal of virtual 

 elimination of mercury. As is stated in Section 2.5 of the TMDL, as of 2006, all of the Northeast states 

 have passed legislation to address mercury in products and require installation of dental amalgam 

 separators. Individual laws and requirements vary by state, but legislation addresses bans on 

 disposal of mercury-added products, bans on sale or distribution of mercury-added novelties and 
Northeast Regional Mercury TMDL – October 2007 88 

 measuring devices, requirements for labeling of mercury-added products, prohibition of primary and 

 secondary schools purchasing or using mercury, removal of mercury switches from automobiles, and 

 requirements on recycling of mercury-added products. Connecticut, Massachusetts, Maine, New 

 Hampshire, and New York have all passed legislation to reduce mercury emissions limits from 

 coal-fired utilities. The end result of all these mercury minimization efforts is that a smaller quantity 

 of mercury makes its way into the waste stream and less mercury is discharged from wastewater 

 treatment facilities. These efforts undoubtedly increase the likelihood of successfully implementing the 

 wasteload allocation. Because these reduction efforts are on-going the states feel there is little

 else that could be done through the NPDES program that could further ensure that the WLA will not 

 be exceeded. Evaluation of progress at the Phase II milestone will determine if mercury minimization 

 plans and additional monitoring at point sources should be prescribed for dischargers that do 

 not already have those programs in place. 

Comment: 

 Stormwater: Because NPDES-regulated stormwater discharges are point sources that must be 

included in the WLA, the TMDL should indicate that any NPDES-regulated stormwater sources are 

subject to the wasteload allocation, regardless of whether the mercury in stormwater originally came 

from atmospheric deposition. In addition, if the WLA is determined by using the same percentage as 

the percentage of point source discharges in the TSL, this approach could result in inaccurate 

computations of the WLA. Thus, we recommend that mercury loadings from NPDES-regulated 

stormwater discharges be included in the estimates of point source mercury loadings in the point 

source portion of the TSL, and that these sources be added to the point source list8

. 

Response: 

The Northeast Regional TMDL for Mercury has been calculated and prepared based on the 

understanding of the states that the primary source of mercury to the waters covered by this TMDL is 

atmospheric deposition. Although the contribution of stormwater to mercury loading is unknown, the vast 

majority of mercury from stormwater that contributes to the impairment of these waters originates from 

air sources and should be controlled accordingly. Regulated stormwater is considered to be part of the de 

minimis WLA, but will be addressed through the controls on atmospheric deposition sources that are 

required to meet the load allocation. The states anticipate that once atmospheric deposition reductions 

are met, the only remaining regulated stormwater contributions would be solely attributed to natural 

sources and run-off from localized non-atmospheric sources. This residual stormwater contribution is 

considered to be a minute part of the WLA. 

The states are already engaged in controlling stormwater pollution using best management practices 

(BMPs) in accordance with Clean Water Act §402(p) and 40 CFR 122.44(k) and any residual mercury in 

stormwater that originates from non-atmospheric sources can be addressed by these programs. The six 

minimum measures associated with permits for municipal separate storm sewer systems (MS4s) will 

contribute toward reducing mercury loading by reducing stormwater volume and sediment loading. 

Comment: 

 Future Growth: The TMDL does not identify an allocation for future growth. The TMDL should 

clarify whether all new or increased discharges would need to stay below the regional WLA8

. 

Response: 

All new or increased discharges will be required to stay below the regional WLA. This statement will 

be added to the revised TMDL. 
Northeast Regional Mercury TMDL – October 2007 89 

7.6 Load Allocation

Comment: 

 We recommend that the TMDL describe whether there are any geographic differences in sources or 

other factors that may affect fish mercury levels. In particular, the TMDL should provide a rationale 

for using a single estimate of deposition for the entire region, and whether there are any geographic 

differences in deposition within the region, e.g., near urban areas or specific sources. If appropriate, 

the TMDL should identify any areas of high local deposition that should be treated separately from 

the rest of the region, in addition to the area in Massachusetts8

. 

Response: 

Because the entire region is impacted by local, regional, and global mercury deposition sources, the 

Northeast states and NEIWPCC feel that it is appropriate to keep the TMDL at the scale of the entire 

region. Any regional differences in deposition are the result of local deposition sources that have 

already been addressed or are in the process of being addressed. Therefore, the entire region is in 

the same position of being primarily impacted by out-of-region sources and therefore feels it is 

appropriate to do the TMDL on a regional basis. 

Kamman, et al. (2005) provides that although there are differences in fish tissue concentrations 

across states, differences in fish tissue concentrations are more strongly influenced by individual fish 

length than they are by jurisdiction. In the case of smallmouth bass, once the effect of length is 

accounted for, there is very little variation in fish concentrations among the states. This relationship 

can be seen in a graph that has been added to the revised TMDL. 

7.7 Margin of Safety 

Comments: 

 In general, we recommend that the margin of safety be more fully justified. The TMDL uses an 

implicit MOS based on two conservative assumptions: use of the fish species with the highest 

mercury concentrations; and use of a midpoint (25%) estimate for contributions from natural sources 

(estimated to range from 15-35%). The description of how sediment cores from rural sites makes the 

natural source estimate conservative should be further explained. For example, use of the midpoint 

would be conservative for the lower end of the range, but not be conservative if the true contribution 

were at the higher end. In addition, use of a top fish species with higher mercury levels would 

typically be more conservative than using data from a lower trophic level fish such as smallmouth 

bass8

. 

 We also suggest you look into whether there are other conservative assumptions in the TMDL that 

may provide an MOS. For example, if the TMDL does not account for reductions in the 

transformation of mercury to methylmercury due to reduced sulfur deposition, this may contribute to 

the MOS8

. 

Response: 

Smallmouth bass is not a lower trophic level fish – it is a high trophic level predator, and therefore 

an appropriate target fish. Additional information will be added to the margin of safety in the revised 

TMDL. The states agree that reduced sulfur deposition (which is occurring through federal and state 

actions) will lead to reduced mercury methylation. This reduction in methylation could potentially 

allow for the necessary reductions in mercury load to be less than proposed in the TMDL, meaning 

that the proposed loads allow for additional protection. 
Northeast Regional Mercury TMDL – October 2007 90 

The states feel that it is more likely that the contribution from natural sources of mercury has been 

overestimated and therefore is more likely to be less than 25 percent instead of greater. The sediment 

cores were taken from rural locations where contributions from natural sources may be greater than 

the region as a whole, which has many urbanized areas. 

An additional piece to add to the margin of safety is that EPA’s fish tissue criterion is for 

methylmercury and the states are actually measuring total mercury in fish. It is estimated that about 

90 percent of total mercury in fish is methylmercury. As states monitor for meeting TMDL goals, 

when fish have met the target of 0.3, 0.2, or 0.1 ppm total mercury, the methylmercury concentration 

will actually be lower, and therefore more protective. 

7.8 Seasonal Variation and Critical Conditions

Comment: 

 Although the TMDL mentions water chemistry and water level fluctuations as affecting mercury 

accumulation over the long term, the TMDL should describe how the critical conditions are being 

addressed or accounted for in the TMDL8

. 

Response:

Because some areas are more sensitive to mercury pollution due to factors such as water chemistry, 

presence of wetlands, and water level fluctuations, these areas may also be more sensitive to 

reductions in mercury emissions and deposition. Therefore, these areas may actually respond more 

quickly to decreases in mercury deposition. However, the exact response of these areas is not known. 

Therefore, these areas are targeted to be more closely monitored during the TMDL implementation 

period. If monitoring results indicate that more specific reduction strategies are necessary for these 

areas, they will be implemented at that time. The adaptive implementation approach will allow for 

changes in the approach to addressing sensitive areas if necessary. 

7.9 Daily Load 

Comments: 

 We believe that daily loading levels of mercury are essentially irrelevant to the goal of the TMDL, 

which should be to prevent mercury from building up in fish tissue over long periods of time. In 

addressing a mercury impairment based on protecting the fish consumption designated use, a daily 

load is not "technically defensible." Therefore, such a loading calculation should not be included in 

the TMDL12. 

 The daily load should not be calculated by simply dividing the annual load by 365. A daily load 

equal to 1/365th of the annual load has no relevance whatsoever to a daily impact on fish 

bioaccumulation of mercury. A more technically reasonable way to develop a meaningful daily load, 

as EPA has recommended in its recently-developed draft "daily load" guidance, is to apply 

recognized statistical techniques to the annual load numbers12. 

 The TMDL should state clearly that the daily load calculation has been done only to implement the 

recommendation in EPA's recent guidance, and is not intended to be implemented in permits12. 

 A daily wasteload allocation for mercury is inappropriate; even if it were appropriate, the proposed 

allocation is technically infirm11. 
Northeast Regional Mercury TMDL – October 2007 91 

Response: 

In a memorandum issued on November 15, 2006 by Ben Grumbles, Assistant Administrator, Water, 

US EPA, provided guidance related to a court decision in the U.S. Court of Appeals, for the D.C. 

Circuit in the Friends of the Earth, Inc. v. EPA, et al., (D.C. Cir. 2006). The purpose of that 

memorandum was to relay EPA’s recommendation that all future TMDLs and associated load 

allocations and wasteload allocations be expressed in terms of daily time increments. The 

memorandum goes on to explain that TMDL submissions can also include alternate non-daily 

expressions for the purposes of implementation of applicable water quality standards. The Northeast 

Regional TMDL does provide an alternate non-daily expression for the mercury load, as well as the 

daily load in order to comply with the EPA recommendation. The approach used in the Northeast 

Regional Mercury TMDL is consistent with the approach used in the Statewide Minnesota Mercury 

TMDL that was approved by EPA in March, 2007. 

9 Implementation 

Comments: 

 It may be useful to at least mention that mercury levels in fish may have effects on aquatic biota as 

well as fish-eating wildlife such as loons, eagles, otters, and minks. At the Phase III review stage, the 

states may want to discuss whether or not whole fish mercury levels are sufficient to also protect fish 

and wildlife9

. 

 Mercury reductions should aim to address the threat not only to human health but also to the health of 

natural ecosystems and to wildlife, especially the State's Species of Greatest Conservation Need. We 

also recommend that, as the TMDL is implemented, the states support research to determine whether 

the steps taken to reduce mercury in fish tissue to consistently safe levels also reduce mercury levels 

sufficiently to achieve ecosystem health and recovery, including among the most vulnerable species 

and ecosystems, and adjust the plan accordingly to achieve both goals10. 

Response: 

Text will be added to the TMDL to briefly describe the concerns associated with mercury and 

wildlife. While the states agree that protection of wildlife is also important, the main goal of the 

TMDL is to protect human health. As resources are limited, the states cannot commit at this time to 

monitoring of mercury levels in wildlife, but some fish monitoring that is carried out for the purposes 

of fish consumption advisories can be used to assess the risk to wildlife. 

Comments: 

 Is there enough being done to make everyone aware of methods to safely dispose of compact 

fluorescent bulbs? What if it ends up in garbage, like most things we use does, and gets into our 

drinking water supply? Are manufacturers putting safeguards in place to “take back” used bulbs and 

dispose of them properly? Is legislation being enacted in New York State and surrounding states to 

this effect? Are stores asked to run such take-back programs? I would like your good offices to 

spearhead this effort. As a state government body that has the interest of safe drinking water for its 

citizens in mind, your office is best positioned to carry out this effort, in collaboration with other state 

governmental agencies4

. 

 NYIPL recommends that NYSDEC come up with a recycling process for CFLs that works. We 

recommend that NYS provide the funding necessary for the towns within the state to recycle these 

mercury wastes as part of their normal recycling programs13. 
Northeast Regional Mercury TMDL – October 2007 92 

Response: 

Effective public education and recycling programs for compact fluorescent lights are issues that 

all of the states are working on addressing at this time. The states acknowledge that more work 

needs to be done in this area and will continue to address this issue. 

Comments: 

 Angler survey data from New Hampshire indicate that smallmouth (and largemouth) bass have a high 

catch-and-release rate and are likely not the most-consumed freshwater fish. It is likely that perch 

(yellow and white) and trout are consumed at higher rates than bass. We believe that perch 

populations should continue to be sampled for mercury in addition to the smallmouth bass6

. 

 The TMDL should not rely solely on mercury concentration in smallmouth bass as indicators of water 

quality. While seemingly ubiquitous, smallmouth bass are invasive species in many traditional 

coldwater fisheries. While brook trout do not bioaccumulate mercury at the same rate as smallmouth 

bass, length-standardized mercury concentrations corresponding to concentrations in smallmouth bass 

should also be calculated for brook trout to allow for monitoring in waterways where smallmouth 

bass are not present5

. 

Response: 

While smallmouth bass is the target species for the TMDL, it is not the only species that states 

will be monitoring. States will continue monitoring other species of fish, such as perch and trout, 

as they have done in the past. Smallmouth bass will be used as indicator for judging if TMDL goals 

are being met, but other species of fish will be monitored as part of normal monitoring program, 

provided that funding is available. Moreover, the calculation method and baseline results for lengthadjusted brook trout and yellow perch are given in Kamman, et al. (2005). 

Comments: 

 The number of impaired waterbodies varies dramatically among states because of different listing 

policies. Does this affect how the TMDL would be implemented in different states7

? 

 Does the list of waterbodies in Appendix A impaired primarily by atmospheric deposition of mercury 

mean that the TMDL will in any way be implemented toward restoring those listed waterbodies vs. all 

water bodies9

? 

Response: 

The Northeast Regional Mercury TMDL covers all of the waterbodies that are listed in Appendix A, 

which for some states includes all of their freshwaters. However, all waterbodies in the Northeast, 

whether they are listed or not, will benefit from the mercury reductions. Implementation of the TMDL 

will result in mercury reductions across the Northeast and not target specific locations within the 

region. 

Comment: 

 We support the "staged implementation" approach as proposed, provided the proposed loading 

reductions for upwind out-of-region sources are applied as described further below3

. 

Comment: 

 Given the difficulty of meeting these goals through the actions of the Northeast states, we encourage 

NEIWPCC to coordinate with other regions to undertake similarly stringent goals for the reduction of 

mercury through the TMDL process. In addition, the states and NEIWPCC should encourage action 
Northeast Regional Mercury TMDL – October 2007 93 

at the federal level to ensure that there is a uniform approach to mercury reductions to protect public 

and environmental health10. 

Response: 

The New England States and New York were able to come together on this TMDL because the seven 

states are similarly impacted by mercury pollution. Further the states have shared data sets as they 

relate to fish tissue and atmospheric deposition and to extrapolate this information to other regions of 

the country would jeopardize the integrity of the data. However, should this approach prove to be 

successful, the states encourage other states and regions to use this TMDL as a model. 

As the comment relates to encouraging action on the federal level, the Northeast states have argued in 

the Opening Brief of Government Petitioners dated January 11, 2006 in the matter of State of New 

Jersey, et al. vs. United States Environmental Protection Agency, the implementation of a strict plantspecific MACT for mercury under section 112(d) of the CAA would result in at least 90 percent 

control of mercury emissions by cost-effective and available technologies. Further, enacting a MACT 

standard under section 112(d) would require compliance within three years of the effective date of the 

standard. This TMDL adds a second dimension to the legal arguments presented by the Northeast 

states in the lawsuit mentioned above by calculating for the first time the extent of reductions needed 

to meet water quality standards in the region’s listed waters and remove fish consumption advisories 

and certainly illustrates the need for federal action. 

Comment: 

 The draft TMDL should take into consideration the adequacy of monitoring practices used by 

municipal waste combustors5

. 

Response: 

The mercury emissions inventory is based on use of emissions factors and/or emissions monitoring 

data for each of the sectors for which emissions are reported. Emissions factors are revised 

periodically, which results in revision to the emissions inventory. The inventory values for MSWC are 

based on considerable stack test data and are viewed as being good quality. Emissions monitoring 

data is collected on an ongoing basis and results will be updated as appropriate. 

Comment: 

 The Clean Water Act does not confer additional authority on EPA or states to regulate air emissions 

sources11. 

Response: 

The intent of the Northeast Regional Mercury TMDL is consistent with the requirements of the Clean 

Water Act in that it sets to establish a pollutant load for mercury – a level at which water quality 

impairments and fish consumption advisories could be eliminated. The calculations provided in the 

TMDL illustrate how much mercury, which is identified as coming primarily from atmospheric 

deposition, must be reduced in order for water quality goals to be achieved. Achieving the loading 

goals set forth in the TMDL can only happen if more stringent controls on air emissions are put into 

place. 

The Northeast Regional Mercury TMDL does not infer that additional statutory authority to regulate 

air emissions is provided by the Clean Water Act. However, that statutory authority already exists 

under the Clean Air Act and can be implemented through state and federal regulatory programs. The 

TMDL simply identifies loading goals and the existing tools states and EPA have to achieve them. 40 

CFR 130.7(b)(1)(iii) specifically states that “Each State shall identify those water quality-limited 

segments still requiring TMDLs within its boundaries for which...Other pollution control 
Northeast Regional Mercury TMDL – October 2007 94 

requirements (e.g. best management practices) required by local, State, or Federal authority are not 

stringent enough to implement any water quality standards (WQS)applicable to such waters.” 

9.1 State and Regional Implementation 

Comment: 

 The states should commit to a more detailed step-wise adaptive implementation method11. 

Response: 

The states feel that the Northeast Regional TMDL already includes a detailed adaptive 

implementation plan. However, there are more details available in state mercury reduction plans 

and status reports. Web addresses for these reports will be provided in the appendices of the revised 

TMDL. 

Comments: 

 Very supportive of Northeast states' decisions to not participate in interstate trading allowed under 

CAMR9

. 

 The Mercury TMDL states that none of the Northeast states will participate in the interstate trading of 

mercury emission credits as allowed under CAMR. The Northeast Environmental Organizations fully 

support this commitment by the States3

. 

Comment: 

 Recommend that states and EPA commit to repeating the Connecticut River Fish Tissue Contaminant 

Study in 20109

. 

Response: 

The states agree that it may be beneficial to repeat the Connecticut River Fish Tissue Contaminant 

Study in 2010, but due to limited resources, cannot commit to it at this time. 

9.1.2 Adaptive Implementation of Load Allocation 

Comment: 

 If fish tissue concentrations decline to levels that meet the 0.3 ppm water quality standards before the 

recommended 86.6 to 98.2 percent reduction in anthropogenic loadings is achieved, the target 

readjustment should be deferred until after the fish tissue concentrations meet the stricter (0.1 ppm) 

water quality standards utilized by Connecticut5

. 

Response: 

The TMDL will continue to be implemented until Connecticut’s 0.1 ppm standard is met. This will be 

more clearly articulated in the revised TMDL. 

9.2 Adaptive National Implementation 

Comment: 

 EPA should include not selling U.S. stockpiles of mercury as part of the strategy to reach Phase II 

goals by 20109

. 
Northeast Regional Mercury TMDL – October 2007 95 

Response: 

The Northeast states agree that not selling U.S. stockpiles of mercury is one strategy that should 

be used to work toward meeting out-of-region reduction goals. This may help to reduce mercury 

emissions from global sources. 

Comments: 

 We further concur with the draft TMDL that the current federal CAMR is insufficient to meet the 

requirements of the TMDL1

. 

 We strongly support New York and the other states that are suing the EPA for not implementing a 

strict MACT standard for power plant mercury emissions1

. 

 It is important that EPA approves the Northeast Regional Mercury TMDL which calls for at least 90 

percent control on out-of-region coal-fired power plants in addition to in-region controls to achieve its 

goals of reducing mercury contamination in Northeast waterbodies14. 

 The Northeast Regional TMDL would help prevent serious human health impacts as well as 

benefiting wildlife and sensitive ecosystems such as the Adirondacks and Catskills. Mercury's health 

and environmental effects are too devastating to leave to market dynamics. Furthermore, cuts must 

be made deeper and quicker than those proposed in the federal CAMR. We feel this plan is a step in 

the right direction for clean water for the future of not only New York but the entire Northeast 

region14. 

 ADK supports the strategy set forth in the Northeast Regional TMDL demonstrating that New York 

and other Northeastern states have taken all possible actions to reduce mercury emissions and 

discharges, providing a basis for EPA to abandon its cap and trade approach to controlling mercury 

emissions and instead include a strict mercury emission standard in Clean Air Act Title V permits for 

Midwestern coal-fired power plants and other industrial facilities14. 

 CCE supports the plan's assertion that more stringent, comprehensive national and international 

mercury control programs are necessary to make fish safe to eat in our region. In order to make fish 

safer to eat in New York, the U.S. EPA should develop a more protective mercury pollution reduction 

program2

. 

 The Northeast Environmental Organizations support and commend the States' efforts to work 

cooperatively to target the primary sources—out-of-region power plants—of the mercury threat to the 

Northeast region by calling for immediate implementation of existing economically and technically 

feasible reduction control technologies on these sources3

. 

 Very supportive of Northeast states in matter of State of New Jersey et al. vs. United States 

Environmental Protection Agency. EPA should start enforcing higher stands at municipal waste 

incinerators, coal plants, and other point sources of mercury throughout the country, using a 

timeframe that will lead to more immediate results9

. 

10 Reasonable Assurances 

Comment: 

 Enhanced pollution controls at municipal waste combustors are the best way to ensure TMDL goals 

are met9

. 
Northeast Regional Mercury TMDL – October 2007 96 

Response: 

The states are currently addressing further reductions of mercury emissions from municipal waste 

combustors through pollution prevention efforts, including legislation regarding management and 

disposal of mercury-containing products. At this time, the states feel that this is the most cost effective 

strategy for reducing emissions from this sector. However, based on developments in technology, the 

states will consider further pollution controls on municipal waste combustors as appropriate. 

Comment: 

 Mercury emissions from residential heating increased between 1998 and 2002. What is this category 

increasing and what can be done about it? The Northeast states should address this issue as a 

significant contributor to in-region emissions9

. 

Response: 

Within the Northeast Mercury Emissions inventory, estimates of emissions from residential heating 

are considered to be the most uncertain. The Northeast States for Coordinated Air Use Management 

is currently conducting a study to improve the confidence in the emissions factor used for this sector. 

The results of this study may show that mercury emissions from this sector were previously 

overestimated. The Northeast states will determine how to address emissions from this sector once 

this study is complete. In addition, NESCAUM is part of an initiative to look at the feasibility of 

using low-sulfur and/or low sulfur biodiesel blend home heating oil that would have co-benefits of 

reduced mercury. 

Comment: 

 The Mercury TMDL clearly establishes that the mandated reductions in mercury loading to the waters 

of the States cannot be met by in-state reductions alone. The Reasonable Assurances section must 

therefore: (i) state that CAMR will be insufficient to achieve the necessary reductions, (ii) require that 

significant reductions be made by upwind out-of-region sources, primarily coal-fired power plants, 

(iii) require that the MACT provisions of section 112(d) of the CAA be adopted as the mechanism for 

implementing these reductions, (iv) state that EPA is obligated under both section 112 of the CAA 

and the loading reduction requirements of the TMDL provisions in section 303(d) of the Clean Water 

Act to act to immediately to reduce the emission of mercury from these sources, and (v) specify that 

the timeframe for implementation shall be as set forth in section 9 of the Mercury TMDL3

. 

Response: 

 The implementation section of the draft TMDL currently addresses the recommended language 

 regarding CAMR and section 112(d) of the CAA. The states go on to recommend adaptive 

 implementation of this TMDL and that a strict 90 percent MACT standard be enacted under section 

 112(d) to meet the national implementation requirements of the TMDL for Phase II (2003-2010). 

 Upon consideration and review of the above comment, the States have modified the TMDL to include 

 this discussion in Section 10: Reasonable Assurances. In addition, in order to better explain goals 

 associated with both the load and waste load allocations, the TMDL has been modified to include 

 clarifying language in those and other appropriate sections of the TMDL. 
Northeast Regional Mercury TMDL – October 2007 97 

Authors of Comments Provided Above: 

1. The Adirondack Council, 342 Hamilton Street, Albany, NY 12210 

2. Citizens Campaign for the Environment, 735 Delaware Road, Box 140, Buffalo, NY 14223 

3. Conservation Law Foundation on behalf of Clean Water Fund, National Wildlife Federation, Mercury 

 Policy Project, Vermont PIRG, New York PIRG, Environmental Advocates of New York, Lake 

 Champlain Waterkeeper, Hudson Riverkeeper, Casco Baykeeper, Saranac Waterkeeper, Upper St. 

 Lawrence Riverkeeper, Soundkeeper, Inc., Environment New Hampshire 

 27 North Main Street, Concord, New Hampshire 03301 

4. Sridhar Venkatesan, 1 Anton Court, Stony Point, NY 10980 

5. Joseph J. Heath, Attorney at Law on behalf of the Onondaga Nation, 716 East Washington Street, 

 Suite 104, Syracuse, NY 13210 

6. New Hampshire Fish and Game Department, 11 Hazen Drive, Concord, NH 03301 

7. Massachusetts Water Resources Authority, Charlestown Navy Yard, 100 First Avenue, Building 39, 

 Boston, MA 02129 

8. U.S. Environmental Protection Agency, Office of Water 

9. Connecticut River Watershed Council, 15 Bank Row, Greenfield, MA 01301 

10. Nature Conservancy, 195 New Karner Rd, Suite 200, Albany, NY 12205 

11. Hunton & Williams LLP on behalf of The Utility Water Act Group, Riverfront Plaza, East Tower, 

 951 East Byrd Street, Richmond, VA 23219 

12. Barnes & Thornburg LLP on behalf of the Federal Water Quality Coalition, One North Wacker 

 Drive, Suite 4400, Chicago, IL 60606 

13. New York Interfaith Power & Light, 401 Parsons Drive, Syracuse, NY 13219 

14. Adirondack Mountain Club, 301 Hamilton Street, Albany, NY 12210