METAALICUS Project: Some of the questions on the rates and factors governing Hg methylation may be answered by the Mercury Experiment to Assess Atmospheric Loading in Canada and the U. S. ( METAALICUS) project currently underway at the Experimental Lakes Area ( ELA) in western Ontario, Canada ( Harris et. al., 2001). METAALICUS is a multidisciplinary whole ecosystem experiment in which a different isotope of Hg in the inorganic form ( Hg( II)) is added to the upland, the wetland, and the lake surface to determine the relationship between atmospheric Hg loading and fish Hg concentrations. One of the goals is to determine how much of the newly deposited atmospheric Hg becomes bioavailable for methylation and biological uptake. 9 209 Implications of Knowledge Gaps Any efforts to reduce MeHg concentration in fish tissue require a clear understanding of the processes that produce MeHg and factors that promote demethylation. Methylmercury production in aquatic systems is not a simple function of total Hg concentration in the system. Rather, as discussed above, it is affected by a number of complex, interrelated factors, which may result in a nonlinear relationship between total Hg and MeHg. Since any or all of these ( or other) parameters can control methylation, either alone or in a complex interrelated process, ecosystems respond differently to changes in these parameters and, at present, there is no simple way to predict methylation rates in natural environments. In the Florida Everglades, for example, contrary to conventional wisdom, the percentage MeHg increases from north to south, opposite the gradients in nutrient, sulfate, and sulfide concentrations ( Gilmour et. al., 1998). Regulatory measures, such as reducing Hg loading rates from atmospheric or point sources, will be less successful in reducing Hg levels in fish without greater understanding of these complex processes.

Marine and Farm Raised Species Because MMaps is designed to simulate natural freshwater systems, EPA does not have an appropriate method for assessing how a change in Hg deposition relates to a change in MeHg in fish tissue found in marine environments or farm raised species.

Time Lag In the NODA, EPA points out that MMaps does not account for the time lag between reducing Hg deposition and reducing MeHg concentrations in fish. In METAALICUS, newly deposited Hg appeared to be more available to bacteria to convert to MeHg than Hg that was in the system for longer periods of time ( historically deposited Hg). EPA also observes that systems that receive most of their Hg input directly from the atmosphere may respond more rapidly to changes in emissions than those receiving significant inputs of Hg from the catchment area. EPA asks for information that can be used to extend or extrapolate the results of the METAALICUS experiment to other freshwater systems and information on Hg cycling and bioavailability in coastal and marine ecosystems.

The findings of the METAALICUS study, as reported in the scientific literature, are valuable because they provide empirical information on the relative importance of Hg sources to Hg cycling in the study lake ( UIF). It should be noted, however, that the principal researchers have acknowledged that caution be used when extrapolating the METAALICUS results to other watersheds. Hintelmann et. al. ( 2002) state that:

This conclusion [ importance of newly deposited mercury to lake cycling and little runoff from the catchment area] is so far limited to terrestrial upland systems such as U1F. Further METAALICUS studies are underway investigating similar processes in wetlands and aquatic ( lake) systems, keeping in mind that lakes receive mercury via direct atmospheric deposition as well as runoff. . . the overall 9 210 contributions of old versus new mercury to mercury in runoff and the overall response time of watersheds to changes in atmospheric mercury deposition will most likely depend on the balance of wet and dry deposition as well as the fraction of rain events that are large enough to cause significant immediate runoff of newly deposited mercury.

While the METAALICUS study suggests a relatively short time lag between rates of Hg addition and lake compartment assimilation, the time lag of such a response will likely be unique to each watershed, and each water body within a watershed. This is because the factors that control the mass loading and mobilization of Hg to water bodies are unique.

Also, the quick response time observed in METAALICUS was observed only for the Hg isotope directly applied to the lake surface. EPA's screening model presently assumes that the same quick and linear response occurs with Hg deposition to uplands as well as water surfaces. The Florida, METAALICUS, Scandinavian, and all other field observations demonstrated quick responses ( and then nonlinear or sub linear) only for directly applied Hg.

EPRI modeled the changes in fish Hg concentrations for four lakes ( two in Wisconsin, one in Ontario, one in Florida) following a hypothetical reduction in inorganic Hg loading to the lakes, using an updated version of D MCM. Different modeling scenarios of varying sediment depth ( 1 3 cm) and exchangeability of inorganic Hg to MeHg ( availability of inorganic Hg for methylation) were performed. The following table indicates the time required for fish Hg concentrations to reach 90 percent of the long term steady state concentration:

Modeling assumptions ( variables) Lake response ( time required for fish tissue Hg at 90 percent equilibrium concentration)

Sediment layer = 3 cm, 100 percent inorganic Hg available for methylation 40 160 yrs Sediment layer = 1 cm, 100 percent inorganic Hg available for methylation ( Pallette Lake) 39 122 yrs Sediment layer = 1 cm, 10 percent inorganic Hg available for methylation 23 yrs The modeling analysis indicates two important results: first, the response time between reductions in extemalloads and stable changed fish tissue concentration is NOT instantaneous ( within 10 years). Secondly, key assumptions of within lake processes ( in this study, two variables affecting Hg availability in sediments) can have a pronounced effect on the predicted timing of long term fish concentration change. This study provides important insights regarding EPA's expectations and assumptions of ecosystem response. In short, a relatively rapid response ( as appears to be indicated by the METAALICUS study) would only be applicable to those types of lakes that the study was conducted at ( northern temperate, oligotrophic). As indicated above, the technical literature is replete with examples showing that non atmospheric load factors are largely responsible for the mobility and bioavailability of Hg. 9 211 Response:

EPA appreciates the commenter's input to the record. Please see the RIA.

4. Step 4: Fish Consumption and Human Exposure. EPA plans to address the relationship between reductions in methylmercury concentrations in fish tissue and reductions in human exposure through consumption. EPA plans on using the National Listing of Fish Advisories, supplemented b the National Fish Tissue Study, for information on methylmercury concentrations in fish and consumption data ( including women of childbearing age, children, subsistence farmers and high end consumers) to determine the relationship between reductions in concentrations in fish tissue and reductions in human exposure. EPA requested comment on whether the methylmercury fish concentration or fish consumption rates used in the Water Quality Criterion could be used for local, regional, or national assessments. EPA also requested data on the usefulness of the fish consumption data provided by the Clean Air Task Force et al ( OAR 2002 0056 3460), Edison Electric Institute ( OAR 2002 0056 2929), Electric Power Research Institute ( OAR 2002 0056 2578), Forest County Potawatomi Community ( OAR 2002 0056 2173), Minnesota Conservation Foundation et. al. ( OAR 2002 0056 2415), and Southern Environmental Law Center ( OAR 2002 0056 4222).

Comment:

One commenter ( OAR 2002 0056 5422) said that EPA should consider the loss of health benefits associated with reduced fish consumption due to an overly conservative reference dose ( RfD) for Hg blood levels in determining net health benefits due to the CAMR. The vast majority of health studies have concluded that the benefits of fish consumption by all segments of the general population far outweigh any effects due to blood Hg levels greater than EPA's RfD and at levels approaching the World Health Organization ( WHO) level of concern. The use of the RfD as the basis for calculating fish warning Hg levels has resulted in a reduction in fish consumption and the related loss of health benefits to the public. The commenter supported the comments of the Center for Science and Public Policy in this regard ( see OAR 2002 0056 5423).

Response:

Although EPA considers inclusion of the NFTS data extremely valuable in providing additional coverage for the study area, it is important to note that the majority of measured fish tissue concentrations were contributed by the NLFA and not by the NFTS. This fact partially addresses the commentor's concerns ( i. e., the benefits analysis primarily reflects NLFA data with a smaller relative contribution from the NFTS dataset). However, several points can be made in response to concerns raised by the commentor regarding the NFTS data. Although NFTS composites do reduce variability ( primarily related to fish size), because size information is available for many of the entries in NLFA, standardization using the NDMMFT model did have access to variability data related to size through the NLFA. The Great Lakes are not being 9 212 included in the primary benefits analysis because of greater uncertainty in linking mercury deposition changes from power plants to fish tissue concentrations relative to lakes and rivers. The relatively small NFTS dataset is offset to some extent by inclusion of the larger NLFA dataset, although concerns of fish tissue sampling coverage ( both spatially and temporally) do persist. For additional information on fish tissue datasets used in the benefits analysis, see Sections 10 and 14.

EPA agrees with the commentor that NLFA data ( when reflecting areas of increased fishing activity) would be preferable to randomly collected data for purposes of supporting a benefits analysis. However, given the patchy nature of the NLFA and the variety of sampling protocols used by different states in collecting data included in the NLFA, EPA considers the NFTS data to be very useful in filling in gaps in coverages and in providing a consistent randomly sampled dataset to augment the purposively sampled data contained in the NLFA.

As described in other responses, the Agency has high confidence in the RfD for methylmercury. EPA encourages the public to vary the species and sources of fish in order to obtain the benefits of fish consumption while avoiding elevated exposures to methylmercury. The fish advisory developed jointly with the Food and Drug Administration emphasizes the benefits of including fish in a healthy diet while informing the public on ways to reduce methylmercury exposure ( http:// www. epa. gov/ waterscience/ fishadvice/ advice. html).

Comment:

Commenter OAR 2002 0056 5475 stated that the EPA defines Hg ` hot spot' as " a mercury deposition point dominated by utility plant contributions whose removal would result in fish tissue levels dropping from above to below the Fish Tissue Criterion of 0.3 ppm." The commenter found this definition to be self limiting, implying no significant Hg impact on the environment when, in fact, the emitting facility may cause a Hg problem without including background Hg emissions. This is an absurd notion since it would allow for any increment of Hg emissions from a specific facility providing the background fish tissue Hg concentration is not below 0.3 ppm. For example, if the Hg fish tissue level for fish found near a utility plant is 1.0 ppm, yet the fish tissue Hg content from background emission sources would still be 0.35 ppm after removal of the Hg from the nearby utility plant, this area would not be considered a ` hotspot' since the fish would still remain over the 0.3 ppm concentration. This commenter stated that besides arbitrarily limiting the identification of local Hg impacts, this type of definition fails to take into account the substantial risk that could be posed by designating significantly elevated Hg concentrations as acceptable.

Response:

EPA has addressed the hot spots issue in the revision Federal Register notice and in the Technical Support Document: Methodology Used to Generate Deposition, Fish Tissue Methylmercury Concentrations, and Exposure for Determining Effectiveness of Utility Emission Controls in the docket. 9 213 Comment:

One commenter ( OAR 2002 0056 5475) stated that the inability to quantify a facility's Hg speciation percentages on an on going basis supports its concern that a cap and trade approach may be inappropriate compared to the standard MACT approach. The actual ` hot spots' that could be allowed to continue to exist as a result of a cap and trade approach may present unacceptable health risks to some of the citizens of Pennsylvania.

Response:

EPA appreciates the commenters concerns. Please see EPA ' s Office of Research and Development white paper ( see Control of Emissions from Coal Fired Electric Utility Boilers: An Update, EPA/ Office of Research and Development, March 2005) for a discussion of the importance of speciation for mercury capture. Also, please see Chapter 7 of the Regulatory Impact Analysis for a discussion of how we took speciation into account in our power sector modeling and see Chapter 8 for a discussion of how we took speciation into account in our air quality and deposition modeling. EPA has addressed the hot spots issue in the revision Federal Register notice and in the Technical Support Document: Methodology Used to Generate Deposition, Fish Tissue Methylmercury Concentrations, and Exposure for Determining Effectiveness of Utility Emission Controls in the docket.

Comment:

One commenter ( OAR 2002 0056 5476) responded specifically to Step 4 of EPA's Proposed Revised Benefits Methodology: Fish Consumption and Human Exposure. This commenter believes that EPA's assumed consumption levels of 142.4 grams/ day underestimates actual levels of fish consumed. The 1993 Survey of Tribal Spearers conducted by the Great Lakes Indian Fish and Wildlife Commission ( GLIFWC ) indicates that Ojibwe tribal members across Minnesota, Wisconsin and Michigan consume anywhere from 155.8 to 240.7 grams/ day in conjunction with fall spearing. The spring spearing season can lead to consumption rates anywhere from 189.6 393.8 grams/ day. The Leech Lake Band of Ojibwe Federally recognized Tribe with MCT membership has reported that they had determined that a fish consumption rate of 227 grams/ day is possible under its treaty protected fish harvesting right. The GLIFWC study also showed that 95 percent tribal respondents consumed at least one meal per week of the walleye caught during spearing and over 12 percent ate more than 7 meals per week. This consumption is very seasonal in nature, with consumption rate varying by as much as 150 grams/ day between the fall and the spring but also has started to show more year round harvest and consumption, as well as extended food storage through freezing. However, GLIFWC's survey is only a minimum threshold since the results are based solely on the those who have participated in the survey for some for traditional gatherers, these numbers may be higher since more traditional gatherers might not respond in a survey but are likely to consume more than the highest numbers the survey participants have reported in this survey.

The 1993 survey reveals that the average meal size may differ widely among groups. EPA 9 214 assumes an average meal size of 6 ounces, or about 170 grams. However, GLIFWC finds that Tribal members responding to the survey and exercising their Fishing rights tend to eat an average meal ranging from 13 27 ounces, or about 369 766 grams; this range being only a minimum.

Mercury levels in fish caught and eaten locally may exceed levels found in commercially available fish or shellfish. U. S. Health and Human Services and EPA data show the commercially important fish like tuna, shrimp, salmon, and catfish can range in concentrations from 0.01 0.35 ppm. But recent EPA data for freshwater fish show that concentrations for important species like walleye, bass, trout, pike, and perch can vary from 0.25 1.03 ppm. This study further shows that, in a representative sampling of fish from U. S. lakes, 80 percent of predator fish levels exceeded US EPA's safe limit of 0.13 ppm for women. Fifty five percent of all freshwater fish ( predatory and non predatory) sampled exceeded this level and 66 percent of all fish sampled exceeded US EPA's safe limit for children under three. By contrast, MCT used a 0.05 ppm trigger level for a 1 meal/ week consumption advisory for sensitive populations.

In all instances, the numbers given above exceed EPA's assumed levels of consumption and Hg content, sometimes by large amounts. In further support of the commenter's viewpoint, EPA's document Fish Consumption and Environmental Justice: A Report Developed from the National Environmental Justice Advisory Committee Meeting of December 3 6, 2001 ( 2002 revised) states that although EPA's numbers are an improvement over previous figures, they do not address consumption at the highest potential rates. The commenter urges EPA to take this new information into account when reviewing data about human exposure.

Both the EPA and the FDA have addressed Hg in fish tissue, but neither has done anything to address Hg in other food sources such as wild rice, moose, and wild birds. According to this commenter, Hg levels in some wild ducks occur at the same levels as in fish tissue. Although these results are from only a limited number of ducks and follow up studies are needed, this is disturbing information that EPA may not be aware of. Because moose, ducks, and other animals eat primarily water plants, they are vulnerable to the effects of Hg poisoning. EPA does not attempt to address cumulative effects of toxic exposures in people who consume large quantities of other natural resources ( e. g., venison, moose, bear, waterfowl, wild rice, blueberries). An analysis of local fish tissue samples typical of those consumed by the commenter were sampled, and commenter consumption advisories were set accordingly. For other MCT component Bands such as the Mille Lacs Band of Ojibwe Indians, the commenter has had to rely on those advisories set by MCT and those set by the State of Minnesota. Sensitive populations are advised to eat no more than one meal per month of most fish species, even if care is taken to eat only the smaller fish of the species. For those fishing for subsistence or cultural practice, this is a ridiculously small amount of fish. It is clear that most Band members are eating amounts in excess of this recommended level of consumption. The commenter does not believe this issue and the issue of persistence of toxic hazards created in the environment due to past weak or neglected resource protection were addressed in EPA's analysis.

The stationary source industries, such as the electric utility and steam generating units, should not have the role to tell the commenter ( via the IPM model) at what level standards should 9 215 be set so they can deliver electricity to the commenter while fulfilling regulations at the least cost to themselves. It is up to EPA to determine how much Hg can be allowed in the environment and for utilities to use their business ingenuity to determine how they can best meet the standards EPA has set. Likewise, EPA should not tell the commenter how many and what type of fish can be consumed. Instead, the commenter should be able to tell EPA what its consumption levels are and EPA should make the fish safe for the commenter at those levels, preferably safe at any level. If this precedence is set, soon EPA will be calling upon the commenter to limit the amount of air it can breath and water it can drink. Limiting consumption of an otherwise healthy food source is not the answer.

The newspaper article " Mercury's Dangers Persist" ( Milwaukee Journal Sentinel, Section G1: April 12, 2004) reported that even when people are aware of the dangers of eating fish from local waters, they often ignore the warnings. Likewise, the commenter believes that many indigenous peoples are unlikely to stop a subsistence based, culturally rich tradition even though concentrations and number of toxic contaminants continue to increase. Despite warnings, some of these people will continue to fish and assume the risk of possibly suffering from ill health effect from toxins or else go hungry. Since Hg can be neither tasted nor smelled in fish meat, this may embolden some consumers to eat more than what is recommended as being safe.

Comments submitted by Electric Public Research Institute ( EPRI) ( Electric Public Research Institute, US EPA Document ID No. OAR 2002 0056 2578, June 26, 2004) addressing fish consumption rates of tribal people do not appear to be accurate. Since EPRI favors less stringent control options than the commenter does, it is highly inappropriate for EPRI to offer information about this subject. EPRI can have no information on this subject that is better than information that comes directly from the tribes. Although EPRI used NHANES and EPA data, it would be far more appropriate to let tribes describe their own consumption patterns, as these vary widely around the nation. EPRI comments that maternal cord blood results showing higher levels of Hg than originally protected have already been accounted for by including a single uncertainly factor for inter individual uncertainty into the derived Reference Dose. EPRI's model assumed a mean consumption rate of 3.7 gram/ day and a maximum of 200 grams/ day. Elsewhere, EPRI used EPA's mean consumption estimate of 14.3 and a 95th percentile rate of 61.63 grams/ day ( comparable to the NHANES numbers of 14 and 68.75 grams/ day). The tribally specific data found by GLIFWC indicate that the actual numbers used should be much higher.

EPRI also made assumptions for the NHANES data about whether fish sampled were freshwater, marine, or farm raised. The commenter prefers the use of locally generated data, rather than NHANES data; through GLIFWC and research conducted by MCT and by the commenter, the commenter has highly localized data that gives real answers about what tribal members eat. The commenter also prefers the use of local data to NHANES data as lake acidity varies widely from region to region and the lakes in Minnesota are of an acidity that readily promotes methylation of Hg. In order to get a truly accurate picture, why not use the best data that is available? EPRI estimated freshwater fraction versus marine fraction for Minnesota is also not indicative of what tribal members eat. The estimate of only 36.55 percent freshwater fish being eaten is far too low. 9 216 Comments submitted by Edison Electric Institute ( EEI) ( Edison Electric Institute, USEPA Document ID No. OAR 2002 0056 2929: June 29, 2004) state that fish consumption is not a problem in the U. S. because only a small portion of fish consumed by U. S. residents is affected by Hg deposition. The commenter strongly disagrees with this statement provided by EEI and instead would say a large portion of the population is consuming fish regardless of their actual Hg levels. The real question should be what is industry doing to ensure all our food sources ( and not just fish) are free of Hg and other toxins such that they will continue to have consumers in the future for their product.

First, if we examine the population numbers, the National Center for Health Statistics states that in the U. S. alone, 4.03 million babies were born in 2001. The 2000 Census shows that there were nearly 62 million women between the ages of 15 and 44. The Center for Disease Control states that in 2003, 70.9 percent of new mothers nursed in the hospital. Out of 4.03 million babies, that means that 2.86 million were breast fed within their first few days of life. This totals up to 68.89 million sensitive humans being exposed to Hg on a daily basis. Breast fed infants were counted twice, as they were exposed both in utero and while breast feeding. Thus, 23 percent of the total U. S. population of 297.3 million is potentially at risk from eating fish.

Second, local fish have been tested and found to contain Hg. Advisories have been issued for local fish consumption, not just by the commenter but by 44 states in the Union. Locally caught fish probably comprise 95 percent of all fish eaten by Band members. If EEI can include such egregiously incorrect statements as these, the rest of its comments are suspect.

EEI further states that most Americans, however, eat little fish. Half of all U. S. citizens eat no fish whatsoever and, of those who do, the weekly average consumption is about one quarter pound. Nearly all this fish is store bought ocean fish, which is unlikely to much Hg emitted from U. S. sources. EEI's comments, at least in this subject, are totally erroneous and unprofessionally naive. Catherine O'Neill's article Mercury, Risk, and Justice ( 34 ELR 11070, 12 2004) refutes this statement with data from NHANES III, which asserts that roughly 88 percent of all adults consume fish and shellfish at least once a month; and 1 percent consume fish daily. This study also shows that the population who eats fish frequently differs greatly from the population who eats fish less often. In short, Americans of color consume fish far more often than white respondents do, which puts these groups at special risks.

The EEI comments also assert that since a recent University of Rochester study has concluded that children in the Seychelles Islands appear to be unaffected by Hg exposure, that the utility industry should be let off the hook. The commenter believes that if the positions were reversed, EEI would also feel also the results of one study cannot totally refute the findings of many other studies. Although the results of the Seychelle study are surprising and show the need for further research, the whole of Hg study and regulation cannot be abandoned over it. In fact, the National Research Council of the U. S. National Academy of Sciences has concluded that the Faroe Islands study is more appropriate for use than the Seychelles study for deriving the Reference Dose ( Clean Air Task Force, Natural Resources Defense Council, U. S. EPA Document ID No. OAR 2002 0056 3460: June 29, 2004). The commenter urges EPA to follow this advice. 9 217 The EEI supports the statement by the American Medical Association that because of the wide variations in the concentrations of Hg in fish and shellfish, it is possible to have the nutritional benefits of moderate fish consumption and avoid fish high in Hg ( cit. Edison Electric Institute, US EPA Document ID No. OAR 2002 0056 2929: June 29, 2004). While this may be true of the typical consumer, subsistence level people do not have the option of spending money on store bought fish or restaurant meals. The fish available to them are native species that come from local waters.

Response:

EPA appreciates the commenter's input to the record. Please see the RIA for a detailed description of EPA's modeling. Please also see EPA's discussion of hot spots in the revision Federal Register notice and in the Technical Support Document: Methodology Used to Generate Deposition, Fish Tissue Methylmercury Concentrations, and Exposure for Determining Effectiveness of Utility Emission Controls in the docket.

Comment:

One commenter ( OAR 2002 0056 5447) noted that a significant reduction in Hg emissions from coal fueled power plants will result in very little change in human exposures in the U. S. A reduction of 7 percent would result in a reduction in MeHg exposure for women of childbearing age by 0.5 to 0.75 percent. 13 While Peabody supports EPA's goal of improving its science related to Hg deposition and bio accumulation of Hg in fish, even a significant improvement in EPA's simplistic modeling will not change the basic conclusion that there will be little overall impact on either Hg deposition in the U. S. or on Hg levels in fish if Hg emissions are decreased from U. S. coal fueled power plants. In contrast, as stated above, the high cost of compliance with these regulations will result in increased electrical costs to consumers and therefore increased mortality.

Response:

EPA appreciates the commenters input. Please see Chapter 11 of the Regulatory Impact Analysis for a description of the benefits of the CAMR.

Comment:

One commenter ( OAR 2002 0056 5458) referred to the EPA and EPRI comment that existing freshwater fish data collected by the States may be biased because it is collected in areas of suspected contamination is misguided. The commenter has a fish sampling program that was developed to protect public health and has been collecting samples in areas where the only known Hg contribution is from atmospheric deposition. To suggest that the National Study of Chemical Residues of Lake Fish Tissue Study is superior for use in a Hg benefits determination over data collected by the State fish surveys is a serious error in judgement by the EPA. The EPA must 9 218 analyze and integrate the existing fish concentration data collected by the States in any assessment of fish consumption. Contrary to the statement in the NODA that this data will overestimate exposure to anglers and their families, the commenter believes this data could be used to get a realistic estimate of exposure to anglers and their families, especially if the anglers are female and of child bearing age.

The commenter is concerned about the use of the National Listing of Fish Advisories. If this database is to be used, it is acknowledged that a bias toward overestimation of Hg concentrations will occur on a national scale. However, other information is available within the states for other waters and/ or species which could reduce or eliminate this bias. The data would be difficult, at best, to accumulate within the time frame necessary for consideration within this rule making. A further confounding factor is a lack of uniformity among the states in the criterion used to cause placement of a health advisory on a fishery containing excessive Hg concentrations. For example, many states use the EPA Hg criterion of 0.3 mg/ kg, whereas some states, including New York, use the US Food and Drug Administration criterion of 1.0 mg/ kg for the establishment of health advice for Hg in fish. Further, for states with a large number of waters ( such as New York with over 7800 lakes, ponds and reservoirs, over 52,000 miles of streams, and 1.1 million acres of marine waters), it is physically and fiscally impossible to examine fish from all waters for Hg concentrations. Therefore, it is a certainty that the National Listing of Fish Advisories will significantly underestimate the numbers and acreage of waters containing fish with Hg in excess of the EPA criterion. Also, upon review of EPA's National Listing of Fish Advisories web page, the commenter found the data presented for individual fish from New York waters are for the years 1990 1997 only, thus, it is somewhat dated, limited and incomplete. The listing of health advisories is current through 2003, but of little value for EPA's purposes ( i. e., to estimate MeHg concentrations in fish and consumption rates of such fish) because actual Hg concentrations are not given and only species with Hg concentrations above the advisory criterion are listed.

The National Study of Chemical Residues in Lake Fish Tissue was designed to provide a statistical representation ( with stratified random sampling by size of lakes) of the relative distribution of Hg in fish throughout the US, although it excludes the Great Lakes. The study was designed to select one composite of a bottom dwelling fish species and one composite of a predator fish species. Recommended bottom dwelling species included brown bullhead or similar catfish species, carp, or white sucker. All these bottom dwelling species are not good accumulators of Hg since they represent lower trophic levels, typically are not predatory, and often do not show substantial accumulations of Hg even when concentrations may be elevated in other species. The predatory species recommended in the project design include largemouth and smallmouth bass and walleye, among others, which represent top level predator species that are good indicators of Hg concentrations within a waterbody, provided they are present within the water. Not all waters sampled will contain one or more of these predator species. Other predator species included in the study ( several species of trout plus northern pike and black or white crappie) provide indications of Hg concentrations that are intermediate between the bottom dwelling fish and the top predators. 9 219 Use of the National Study of Chemical Residues in Lake Fish Tissue results could present bias based on how the data is presented. First, the five Great Lakes are excluded, and each of the Great Lakes are known to contain species of fish which exceed the EPA Hg criterion of 0.3 mg/ kg, therefore, millions of acres of water may be excluded from consideration, i. e., 2.65 million acres in New York alone. Second, the relative proportion of lakes adversely affected by Hg could be characterized as either numbers of waters or surface acreage. Characterization by both methods should be incorporated into an evaluation to give a more accurate description of impact and potential benefits to be derived. Other concerns that the commenter has about the utility of this study as it relates to EPA's goals include: 1) measurements of variability in the data will be limited because samples are composites ( i. e., only one data record for each species per lake); 2) sample composites limit assessments to one size class of fish per lake, restricting the chance to examine fish size Hg concentration relationships; 3) this study will only provide a very generic regional assessment of fish Hg concentrations because less than 0.5 percent ( n= 25) of the lakes in the state were sampled and the distribution of those lakes selected do not reflect the distribution of lakes within the state ( lakes in the Adirondacks, a six million acre area known to have Hg issues, represent over 60 percent of lakes in New York while only 36 percent of the national study lakes in New York were from the Adirondacks); 4) the analysis of only two species per lake is restrictive and the data are further diluted because species selection varied by lake; and 5) overall this was a screening level study with limited application for determining important regional and size/ species related Hg concentration patterns in a variety of popular and edible fish species.

The commenter is concerned with some of the potential assumptions that can be used to determine human exposure and requests that the EPA adhere to the maximum individual risk ( MIR) concept as discussed in the Residual Risk Report to Congress. In the case of MeHg exposure, the MIR represents the highest estimated risk to an exposed individual based on realistic high end consumption and fish Hg concentration inputs. The use of the average Hg concentration for the average fish combined with the average fish consumption rate will result in an average benefit determination that will underestimate the benefits of reducing Hg emissions. The EPA exposure handbook has fish consumption rate for the 95th percentile at 25 grams per day for non subsistence people and 170 grams per day for subsistence fish eaters. The EPA Methyl Mercury Water Quality Criterion uses freshwater fish consumption rates of 156.3 grams/ day for children, 165.5 grams / day for women of child bearing age and 17.5 grams/ day for adults in the general population. The benefits analysis should reflect the MIR concept and use the high end consumption parameters for fish consumption for women of childbearing age and children to insure a proper accounting of the benefits of reducing Hg emissions for this sector of the population.

Response:

Please see Chapter 5 of the RIA for a discussion of concentrations of mercury in fish. Please also see the Revision of December 2000 Regulatory Finding on the Emissions of Hazardous Air Pollutants from Electric Utility Steam Generating Units and the Removal of Coal and Oil fired Electric Utility Steam Generating Units from the Section 112( c) List for a discussion of the Agency's rationale for not proceeding under Section 112 Notice and in the 9 220 Technical Support Document: Methodology Used to Generate Deposition, Fish Tissue Methylmercury Concentrations, and Exposure for Determining Effectiveness of Utility Emission Controls in the docket.

Comment:

One commenter ( OAR 2002 0056 5535) presented below, several specific issues that would benefit from such careful peer review. The commenter did not intend this list to be comprehensive, but merely included it to illustrate that the agency must address critical scientific issues prior to making changes to its deposition and watershed models or conducting other components of the proposed analyses. This overview serves to demonstrate that it would be foolish to hold up final Hg regulations while EPA further investigates certain technical issues concerning the emissions, fate, and toxicity of Hg from power plants.

Hg deposition and estuarine and marine species. Although EPRI has conducted an assessment of the impact of Hg deposition on marine and estuarine fish species, this is a particular area where EPA needs to consult the broader scientific community.

The commenter urged the agency to give additional weight to the findings of the METAALICUS project as the researchers on this team are internationally recognized Hg experts conducting unbiased scientific research. The commenter noted that EPA was quick to emphasize that results from METAALICUS were ongoing and still being refined while offering no such caution when describing PERI's conclusions on numerous scientific issues ( e. g., plume transformation, global inventories, global transport of Hg, marine impacts, human exposure, etc.)

The Mercury Report to Congress contains a large amount of data on high end fish consumers. EPA should augment this information with more recent regional studies on fish consumption patterns such as have been conducted in New England.

The commenter continued to take issue with the current EPA definition of hot spots which is limited to levels of Hg in fish tissue that would cause the human population to exceed the RfD. Given the human and ecological health risks associated with Hg exposure, the definition of hot spots should be recast to include local, regional and national hot spots as identified by ( 1) hot spots in deposition, ( 2) hot spots in water, and ( 3) hot spots in biota.

New research regarding the extent of Hg in water, fish and wildlife and the occurrence of hot spots in the Northeast U. S. is forthcoming in the journal Ecotoxicology. EPA should incorporate these findings is any new assessments of the impacts of Hg emissions.

The commenter stated that despite the scientific uncertainties of the broad assessment that EPA has described, the agency can still improve the benefits assessment in the short term for the purpose of preparing a Regulatory Impacts Analysis for the final rule. Specifically, an assessment and monetization of cardiovascular effects in children and adults and the loss of IQ points in children can be accomplished with the data at hand concerning Hg blood levels in the U. S. 9 221 Response:

Please see Chapter 3 of the CAMR Regulatory Impact Analysis for a detailed discussion of mercury in the environment, including an assessment of the response time for systems after a change in mercury deposition. Please also see Section 8 for a discussion of the change in mercury deposition based on air quality modeling and Chapters 11 for a benefits analysis of the CAMR. Please also see the Revision of December 2000 Regulatory Finding on the Emissions of Hazardous Air Pollutants from Electric Utility Steam Generating Units and the Removal of Coal and Oil fired Electric Utility Steam Generating Units from the Section 112( c) List for a discussion of the Agency's rationale for not proceeding under Section 112 Notice and in the Technical Support Document: Methodology Used to Generate Deposition, Fish Tissue Methylmercury Concentrations, and Exposure for Determining Effectiveness of Utility Emission Controls in the docket.

Comment:

The commenter ( OAR 2002 0056 5465) stated that additionally, they would like to address Part II of the NODA, " Step 4 of EPA's Revised Benefits Methodology: Fish Consumption and Human Exposure." Again, note that by focusing its comments, the commenter does not mean to suggest that this is the only step in EPA's proposed method that warrants critique.

As EPA noted, consumption of fish was the primary pathway for human exposure to MeHg. As such, two sets of factors became important to determining human exposure: those describing the concentration of MeHg in fish tissue and those describing fish consumption practices for humans.

Methylmercury Concentration In the NODA, EPA indicated that it is considering looking to the National Study of Chemical Residues in Lake Fish Tissue ( also referred to as the National Fish Tissue Study ( NFTS)), given its concern that data from the EPA's National Listing of Fish Advisories ( NLFA), which is collected by state agencies, may be " biased." Specifically, EPA argued that the fact that states generally collect fish tissue Hg data from ( a) " areas of increased angling activity," and ( b) " areas of suspected contamination" means that this data may " overestimate exposure to anglers and their families." This concern is largely misplaced. First, from a public health perspective, it is entirely appropriate to sample from areas likely to be fished, i. e., " areas of increased angling activity," in order to determine the MeHg concentration in species likely to be consumed by humans. To prefer a random sampling method ( as undertaken in the NFTS) is to misfocus the relevant inquiry. If the waterbodies sampled are not fished by humans, then humans are not going to be exposed via fish in those waterbodies. The effect, of course, is to dilute the relevant value for mean MeHg concentration in fish tissue, resulting in an estimate of exposure that is inaccurate and thus scientifically unsound. On a related note, it makes sense to consider, additionally, the concentration in the tissue of fish caught in areas once favored by humans but no longer fished 9 222 due to advisories warning of contamination. Because humans would fish in these areas but for unaddressed contamination, it is reasonable to set environmental standards at levels protective of consumption here. Second, although some states and tribes initially began their data collection efforts with waterbodies that they believed to be contaminated, it should be kept in mind that many states and tribes have been gathering this data for some time, and have now sampled broadly and extensively from the waterbodies within their respective jurisdictions. In fact, the commenter urged the EPA to consult with the Great Lakes Indian Fish and Wildlife Commission ( GLIFWC) about data they have gathered that documents MeHg concentration in the tissue of locally consumed species at levels greater than suggested by state or federal data.

Fish Consumption Rates and Practices EPA stated in the NODA that it is seeking information on fish consumption rates by different affected populations, particularly in the eastern half of the U. S. The commenter referred EPA to the analysis of various groups' fish consumption practices conducted by Professor O'Neill ( in the attached article, see OAR 2002 0056 5465) and to the fish consumption rates for the various Ojibwe and other Great Lakes tribes cited therein. The commenter also referred EPA to the discussion and studies in the report of the National Environmental Justice Advisory Committee, Fish Consumption and Environmental Justice.

EPA asked specifically whether the fish consumption rates used in the Water Quality Criterionx or produced in the Peterson, et al., study are appropriate for assessing the effects on, inter alia, tribal populations. In the first place, the commenter emphasized that the only ones with the knowledge to respond to this question are the affected tribes themselves. Thus, if EPA is to produce an accurate and defensible assessment, it must pose this question directly to the various tribes. Moreover, EPA should honor its commitment to consult with tribes on a government to government basis on issues, such as this, that affect tribal rights and resources.

Although the commenter deferred to tribes' individual responses to the above question, it nevertheless noted that the fish consumption rates used by the Water Quality Criterion ( produced by the national CSFII study) and produced by the local Peterson, et. al., study are markedly lower   more than an order of magnitude lower  than the fish consumption rate produced by a 1993 GLIFWC survey of tribal spearers ( 189.6 to 393.8 grams/ day in the spring) and the fish consumption rate adopted by the Leech Lake Band, one of the Minnesota Chippewa Tribe members ( 227 grams/ day). These differences and their implications are elaborated in the attached article by Professor O'Neill. Further ( see OAR 2002 0056 5465) , a host of other aspects of tribal members' different fish consumption practices ( e. g., " acute" consumption in accordance with seasonal or cultural practices; different average meal size; different species consumed) are relevant to an assessment of exposure and must be considered by EPA. Several of these aspects are discussed in the attached article by Professor O'Neill ( see e docket OAR 2002 0056 5465); in addition, CPR refers EPA to discussions by tribal commenters such as the Fond du Lac Tribe. xii As a general matter, in assessing the effects on tribal populations, EPA should eschew data from studies that are national in focus ( such as the CFSII study) and/ or are non tribally conducted ( such as the Peterson, et al., study), in favor of studies of the relevant tribal population conducted 9 223 by the tribe/ the relevant intertribal association ( or at least suggested by the tribe in consultation). Such a preference would produce more accurate and therefore scientifically defensible results. In this vein, the commenter found EPRI's suggested fish consumption rates particularly ill conceived. PERI purports to construct " local" fish consumption rates, but does so by weaving together a host of assumptions that simply do not comport with actual local practice, that serve chiefly to underestimate exposure ( e. g., PERI assumes a fish MeHg concentration of 0.12 mg/ kg MeHg), and that work backward from NHANES data on blood Hg levels to fabricate likely consumption rates for each state  a highly questionable method in the face of numerous empirical studies documenting actual local consumption rates.

Finally, the commenter noted that EPA needed to account for the fact that the tribal consumption rates described in the Peterson, et al., study may reflect current consumption levels that are artificially low. As the Peterson study itself notes, some tribal members may have already altered their fishing and fish consumption practices to some degree in view of the fish consumption advisories issued by the states and the tribes. To the extent this is the case, the fish consumption rate that is generated by a survey such as that conducted by Peterson does not reflect what tribal members would consume, were the fish not contaminated with Hg. Patrick West, et al., termed this the " suppression effect:" that is, the fish consumption rate revealed by surveys in these instances reflects a " suppressed" rate of consumption. This point applies with particular force to tribes, who have treaty guarantees to a certain level of consumption. Even if tribal members have had to forego fish recently because fish have been allowed to become contaminated, they are entitled not to do so; thus environmental standards should be set to protect consumption at the higher, treaty guaranteed level of consumption, not the lower, suppressed level of consumption. Again, tribes will be uniquely positioned to be able to identify and account for suppression effects for their populations; as such, tribally conducted studies or tribally interpreted data are to be preferred.

Response:

EPA agrees that for some situations ( e. g., commenter examples) the value 142.4 may be an underestimate of fish consumption. This is the value that the Agency recommends in its water quality standards program to States with high consuming sub populations, in lieu of site specific data when those states are faced with developing a water quality standard for methylmercury that is protective of the fish consumption use of state waters demonstrated by those subpopulations Where a state has local information indicating higher rates of fish consumption than 142.4, it is recommended that they use it. In the benefits analyses performed for this rule, several consumption scenarios were considered based on the available data pertinent to the population modeled ( recreational anglers), but the value of 142.4 g/ day was not used.

The EPA has included four potentially high risk populations in the RIA, including: ( a) high end recreational fisher anglers ( with consumption rates at or above the 95th percentile for this group), ( b) economically disadvantaged high end consumers with poverty status income and fish consumption rates at or above the 95th percentile for freshwater anglers, ( c) Hmong in Minnesota and Wisconsin and ( d) Chippewa in Minnesota, Wisconsin and Michigan. These 9 224 special population are intended to provide coverage for groups of individuals who through choice, necessity or socio cultural practices consume relatively high levels of self caught freshwater fish. Inclusion of these four special populations is also intended to support consideration of distributional equity in relation to EGU based environmental regulation ( i. e., would a subset of the US population benefit disproportionately from regulations to reduce mercury emissions from EGUs)?

Fish consumption rates for all four special populations have been developed based on peer reviewed survey data that are representative of the particular group of interest. In the case of the Chippewas, EPA has used a mean value obtained from the literature ( see RIA Chapter 10 for additional details). However, it was not possible to identify a high end percentile consumption rate based on peer reviewed literature and consequently, the mean consumption rate was used in the benefits analysis without consideration for variability in fish consumption rates across individuals. However, in response to information provided in NODA comments ( including that provided by this commentor), EPA has conducted a sensitivity analysis for highend fish consumption by the Chippewa population using ( a) the maximum delta fish tissue concentration ( for Walleye) modeled in states where Chippewa are located for the RIA for Option 1 and Option 2 ( i. e., the maximum change in MeHg fish tissue concentrations modeled in Michigan, Wisconsin or Minnesota under CAMR Options 1 and 2) and ( b) the maximum seasonal fish consumption rate provided in the NODA comments ( i. e., 393.8 g/ day). The results suggest that total IQ reductions under Option 1 and 2, even under these conservative assumptions ( i. e., highest change in mercury fish tissue concentrations under Option 1 and Option 2 and the highest seasonal fish consumption rate), are relatively low at 0.32 IQ points per child. This relatively low IQ benefit for this conservative scenario reflects the fact that, while states where the Chippewa are located may have relatively high absolute ( total) MeHg concentrations in target fish species, modeled EGU deposition over these areas is relatively low and consequently, CAMR is likely to produce relatively small changes in mercury fish tissue concentrations compared with other areas where EGU deposition is higher ( e. g., the Ohio river valley). These findings argue against a distributional equity concern for the Chippewa in this portion of the study area ( although this conclusion needs to be considered in the context of the overall precision and specificity of the benefits model used in this RIA which is not intended for site specific analysis and was developed for application at the regional level).

EPA acknowledges that states contributing data to the NLFA may use different protocols that result in mercury fish tissue concentrations having different degrees of bias ( e. g., focus on most impacted waterbodies versus waterbodies most heavily fished). The degree of uncertainty and potential relevance in adversely impacting the RIA will depend on the specific protocol being considered. If a state focuses fish sampling on areas experiencing heavy fishing activity, then this will actually benefit the economic analysis by contributing fish tissue measurements from waterbodies experiencing fishing activity. Conversely, states that focus on areas believed to have a mercury contamination problem, could bias the NLFA dataset in a conservative direction if those waterbodies are not fished relative to other less impacted waterbodies. Given potential concerns over the NLFA and potential bias resulting from the individual state's sampling protocols, EPA completed a statistical comparison of the NLFA and the NFTS datasets ( the 9 225 NFTS uses a rigorous statistical sampling procedure to provide unbiased coverage for waterbodies). This statistical comparison showed that the NLFA and NFTS datasets were indistinguishable statistically except at the extreme high end, where there was some conservative bias identified in the NFTS. These findings support the use of the NLFA ( along with the NFTS) in conducting national or regional benefits analyses, since these analyses focus on generalized trends in mercury fish contamination. However, EPA acknowedges that assessments of extreme high end exposure and risk could be biased somewhat high if the NLFA data are used. However, it is important to reiterate that, if the NLFA bias reflects waterbodies where fishing activity is likely, then this identified high end bias may not be problematic and indeed, could be preferred ( i. e., it would not represent true bias).

Although EPA considers inclusion of the NFTS data extremely valuable in providing additional coverage for the study area, it is important to note that the majority of measured fish tissue concentrations were contributed by the NLFA and not by the NFTS. This fact partially addresses the commentor's concerns ( i. e., the benefits analysis primarily reflects NLFA data with a smaller relative contribution from the NFTS dataset). However, several points can be made in response to concerns raised by the commentor regarding the NFTS data. Although NFTS composites do reduce variability ( primarily related to fish size), because size information is available for many of the entries in NLFA, standardization using the NDMMFT model did have access to variability data related to size through the NLFA. The Great Lakes are not being included in the primary benefits analysis because of greater uncertainty in linking mercury deposition changes from power plants to fish tissue concentrations relative to lakes and rivers. The relatively small NFTS dataset is offset to some extent by inclusion of the larger NLFA dataset, although concerns of fish tissue sampling coverage ( both spatially and temporally) do persist. For additional information on fish tissue datasets used in the benefits analysis, see Sections 10 and 14.

Comment:

One commenter ( OAR 2002 0056 5455), in reference to fish consumption and human exposure, responded specifically to Step 4 of EPA's Proposed Revised Benefits Methodology: Fish Consumption and Human Exposure. The commenter believed that EPA's assumed consumption level of 142.4 grams/ day underestimates actual levels consumed by the commenters. A survey by the Great Lakes Indian Fish and Wildlife Commission ( GLIFWC) indicated that members of Ojibwe Great Lakes tribes consumed anywhere from 155.8 240.7 grams/ day in conjunction with fall spearing. The spring spearing season can lead to consumption rates anywhere from 189.6 393.8 g/ day. The Leech Lake Band, one of the Minnesota Chippewa Tribe member bands, has determined that a fish consumption rate of 227 g/ day is possible under its treaty protected fish harvesting right. The GLIFWC study also showed that 95 percent tribal respondents consumed at least one meal per week of the walleye caught during spearing and over 12 percent ate more than 7 meals per week. This consumption is very seasonal in nature, with consumption rates varying by as much as 150 g/ day between the fall and the spring. The survey also reveals that the average meal size may differ widely among groups. EPA assumes an " average" meal size of 6 ounces, or about 170 grams. However, GLIFWC finds that tribal fishers 9 226 tend to eat an " average" meal ranging from 13 27 ounces, about 369 766 grams. EPA should adjust their analysis accordingly.

Mercury levels in fish caught and eaten locally may exceed levels found in commercially available fish or shellfish. U. S. Health and Human Services and EPA data show that commercially important fish like tuna, shrimp, salmon, and catfish can range in MeHg concentrations from 0.01 0.35 parts per million ( ppm). But recent EPA data for freshwater fish show that MeHg concentrations for important species like walleye, bass, trout, pike, and perch can vary from 0.25 1.03 ppm. This study further shows that, in a representative sampling of fish from U. S. lakes, 80 percent of predator fish levels exceeded EPA's safe limit of 0.13 ppm for women. Fifty five percent of all freshwater fish ( predatory and non predatory) sampled exceeded this level and 76 percent of all fish sampled exceeded EPA's safe limit for children under three. By contrast, the commenter used a 0.05 ppm trigger level for a " 1 meal/ week" consumption advisory for sensitive populations.

In all instances, the numbers given above exceed EPA's assumed levels of consumption and Hg content, sometimes by large amounts. In further support of our viewpoint, EPA's document Fish Consumption and Environmental Justice: A Report Developed from the National Environmental Justice Advisory Committee Meeting of December 3 6, 2001 ( 2002 revised), states that although EPA's numbers are an improvement over previous figures, they do not address consumption at the highest potential rates. Please take this new information into account when reviewing your data about human exposure.

EPA made no attempt to address cumulative effects of toxic exposures in people who consume large quantities of other natural resources ( i. e., venison, moose, bear, waterfowl, wild rice, blueberries), although this would be a scientifically sound idea if EPA truly wants to protect sensitive members of the population. An analysis of local fish tissue samples typical of those consumed by the commenters were analyzed and Reservation consumption advisories set accordingly. Sensitive populations are advised to eat no more than one meal per month of most fish species, even if care is taken to eat only the smaller fish of the species. For those fishing for subsistence or cultural practice, this is a ridiculously small amount of fish. It is likely that most commenters were eating amounts in excess of this recommendation. Also, because the fish are harvested with nets, it is impossible to target " safe" sizes. This issue was also not addressed in EPA's analysis.

As alluded to in the previous paragraph, EPA has addressed Hg in fish tissue but has done nothing to address Hg in other food sources such as wild rice, moose, and waterfowl. The commenter had found that Hg levels in some wild ducks occur at the same levels as in fish tissue. Although these results are from only a limited number of ducks and follow up studies are needed, this is disturbing information that EPA may not be aware of. Because moose, ducks, and other animals eat primarily water plants, they are vulnerable to the effects of Hg poisoning.

It should not be utility's role to tell the public ( via the IPM model) at what level standards should be set so they can deliver electricity to us while fulfilling regulations at the least cost to 9 227 themselves. It is up to EPA to determine how much Hg can be allowed in the environment and for utilities to use their business acumen to determine how they can best meet the standards EPA has set. Likewise, EPA should not tell tribes how many and what type of fish they can consume. Instead, the tribes should be able to tell EPA what their consumption levels are and EPA should make the fish safe for them to consume at those levels. If this precedence is set, soon EPA will be calling upon us to limit the amount of air we can breathe and water we can drink. Limiting consumption of an otherwise healthy food source is not the answer.

Studies showed that even when people were aware of the dangers of eating fish from local waters, they often ignored the warnings. Likewise, the commenter believed that many tribal people are unlikely to give up a subsistence based, culturally rich tradition even though warnings have been issued. Some of these people will either continue to fish or go hungry. Since Hg can be neither tasted nor smelled in fish meat, this may embolden some consumers to eat more than is safe. Furthermore, most people are unaware of recent findings indicating that consumption of Hg contaminated fish can lead to heart disease. Both men and those women not of childbearing age may be over consuming based on their ignorance of this information.

Comments submitted by PERI addressing fish consumption rates of tribal people are not accurate. Since PERI favors less stringent control options than the tribes do, it is highly inappropriate for PERI to offer information about this subject. PERI can have no information on this topic that is better than information that comes directly from the tribes. Although PERI used NHANES and EPA data, it would be far more appropriate to let tribes describe their own consumption patterns, as these vary widely around the nation. PERI comments that maternal cord blood results showing higher levels of Hg than originally thought have already been accounted for " by including a single uncertainly factor for inter individual uncertainty into the derived Reference Dose." The commenter wonders why Reference Doses got only one factor of uncertainty while the MACT standard calculated by EPA contains several factors to correct for variability in MACT floor calculations, compliance methods, fuel types, etc.. EPRI's model assumed a mean consumption rate of 3.7 g/ day and a maximum of 200 g/ day. Elsewhere, PERI used EPA's mean consumption estimate of 14.3 and a 95th percentile rate of 61.63 g/ day ( comparable to the NHANES numbers of 14 and 68.75 g/ day). The tribally specific data given earlier in this letter indicated that the actual numbers used should be much higher to account for seasonal variation. While the commenter assumed a daily consumption rate of 60 g/ day in setting its water quality standards, this rate of consumption is believed to be far more common than what would occur at the 95th percentile."

PERI also made assumptions for the NHANES data about whether fish sampled were freshwater, marine, or farm raised. Again, the commenter preferred the use of locally generated data, rather than NHANES data, because such localized data gives real answers about what tribal members eat, which are better than projections from non tribal people. In addition, local data helps capture lake acidity variability that occurs from region to region. As lakes in northern Minnesota are of an acidity that readily promotes methylation of Hg, the commenter believed it is essential that local data be used as much as possible. In order to get a truly accurate picture, why not use the best data that is available? EPRI's estimated " freshwater fraction versus marine 9 228 fraction" for Minnesota is also not indicative of what tribal members eat. The estimate of only 36.55 percent freshwater fish ( of total fish consumed) is far too low.

Comments submitted by Edison Electric Institute ( EEI) stated that fish consumption is not a problem in the U. S. because only a small portion of fish consumed by U. S. residents is affected by Hg deposition. A large portion of the population is consuming fish, and those fish are contaminated with Hg. First, let's look at population numbers. The National Center for Health Statistics states that, in the U. S., 4.03 million babies were born in 2001. The 2000 Census shows that there were nearly 62 million women between the ages of 15 and 44. The Center for Disease Control states that in 2003, 70.9 percent of new mothers nursed in the hospital. Out of 4.03 million babies, that means that 2.86 million were breast fed within their first few days of life. This totals up to 68.89 million sensitive humans being exposed to Hg on a daily basis. Breast fed infants were counted twice, as they were exposed both in utero and while breast feeding. Thus, 23 percent of the total U. S. population of 297.3 million is potentially at risk from eating fish. Second, local fish have been tested and found to contain Hg in levels that exceed EPA recommendations. Advisories have been issued for local fish consumption, not just by the commenter but also by 44 states in the Union. Locally caught fish probably comprise 95 percent of all fish eaten by Band members. If EEI can include such egregiously incorrect statements as these, the rest of its comments are suspect.

EEI further claims, " Most Americans, however, eat little fish. Half of all Americans eat no fish whatsoever and, of those who do, the weekly average consumption is about one quarter pound. Nearly all this fish is store bought ocean fish, which is unlikely to contain much Hg emitted from U. S. sources". This statement is totally erroneous and downright bizarre. Catherine O'Neill's article refutes this statement with data from NHANES III, which asserts " roughly 88 percent of all adults consume fish and shellfish at least once a month; and 1 percent consume fish daily." This study also shows that composition of the group who eats fish frequently differs greatly from the group who eats fish less often. In short, Americans in minority groups consume fish far more often than white respondents do, putting these groups at higher risk.

The EEI comments also assert that since a recent University of Rochester study has concluded that children in the Seychelles Islands appear to be unaffected by Hg exposure, the utility industry should be let off the hook. As I'm sure EEI would feel if the positions were reversed, the results of one study cannot totally refute the contradictory findings of many other studies. Although the results of the Seychelles study are surprising and show the need for further research, the whole of Hg study and regulation can't be abandoned over it. In fact, the National Research Council of the U. S. National Academy of Sciences has concluded that the Faroe Islands study is more appropriate for use than the Seychelles study for deriving the Reference Dose. The commenter urged EPA to follow this advice rather than the biased comments from EEI.

The EEI supports the statement by the American Medical Association that " because of the wide variations in the concentrations of Hg in fish and shellfish, it is possible to have the nutritional benefits of moderate fish consumption and avoid fish high in Hg." While this may be true of the typical consumer, subsistence level people do not have the option of spending money 9 229 on store bought fish or restaurant meals. The fish available to them are native species that come from local waters.

So, in summary, the commenter did not agree with the fish consumption rates used in this rulemaking. The Water Quality Criterion uses a consumption rate of 17.5 g/ day ( or lower), which has been shown to be too low for tribal people. The commenter also was suspicious of the consumption rates given in Peterson, et. al., because they do not agree with data obtained from GLIFWC and the Leech Lake Band. The commenter had not had sufficient time to thoroughly review the Peterson study, the commenter are simply wary of its results. It could be that the people surveyed have already changed their consumption habits to account for Hg contamination. If so, it is an example of an indirect curtailing of treaty rights and is unacceptable. The relatively low consumption patterns evidenced by the study may also be a function of efforts made by the Wisconsin Department of Natural Resources and by the specific tribal governments to inform people of consumption advisories. As an Environmental Justice aside, let me point out the Peterson study's finding that Hg levels were highest among the unemployed.

The NODA also seeks comment on EPA's plan to use National Fish Tissue Study ( NFTS) values for methylHg concentrations in fish. EPA favors the use of NFTS data over National Listing of Fish Advisories ( NLFA) data because the former were gathered by random sample while the NLFA data are gathered from areas of increased angling activity and from areas of suspected contamination ( as explained in the NODA). The commenter believed this reasoning is exactly backward. If one wants to protect the most sensitive members of the population, worst case scenarios must be considered. That means looking at those who eat the highest quantities of fish and those who eat the most heavily contaminated fish. The commenter believed this is highly appropriate based on a public health perspective. Second, GLIFWC data suggests levels of contamination higher than those put forth by EPA.

Response:

EPA agrees that for some situations ( e. g., commenter examples) the value 142.4 may be an underestimate of fish consumption. This is the value that the Agency recommends in its water quality standards program to States with high consuming sub populations, in lieu of site specific data when those states are faced with developing a water quality standard for methylmercury that is protective of the fish consumption use of state waters demonstrated by those subpopulations Where a state has local information indicating higher rates of fish consumption than 142.4, it is recommended that they use it. In the benefits analyses performed for this rule, several consumption scenarios were considered based on the available data pertinent to the population modeled ( recreational anglers), but the value of 142.4 g/ day was not used.

EPA has included four potentially high risk populations in the RIA, including: ( a) highend recreational fisher anglers ( with consumption rates at or above the 95th percentile for this group), ( b) economically disadvantaged high end consumers with poverty status income and fish consumption rates at or above the 95th percentile for freshwater anglers, ( c) Hmong in Minnesota and Wisconsin and ( d) Chippewa in Minnesota, Wisconsin, and Michigan. These 9 230 special population are intended to provide coverage for groups of individuals who through choice, necessity or socio cultural practices consume relatively high levels of self caught freshwater fish. Inclusion of these four special populations is also intended to support consideration of distributional equity in relation to EGU based environmental regulation ( i. e., would a subset of the US population benefit disproportionately from regulations to reduce mercury emissions from EGUs)?

Fish consumption rates for all four special populations have been developed based on peer reviewed survey data that are representative of the particular group of interest. In the case of the Chippewa, EPA has used a mean value obtained from the literature ( see RIA Chapter 10 for additional details). However, it was not possible to identify a high end percentile consumption rate based on peer reviewed literature and consequently, the mean consumption rate was used in the benefits analysis without consideration for variability in fish consumption rates across individuals. However, in response to information provided in NODA comments ( including that provided by this commenter), EPA has conducted a sensitivity analysis for highend fish consumption by the Chippewa population using ( a) the maximum delta fish tissue concentration ( for Walleye) modeled in states where Chippewa are located for the RIA for Option 1 and Option 2 ( i. e., the maximum change in MeHg fish tissue concentrations modeled in Michigan, Wisconsin or Minnesota under CAMR Options 1 and 2) and ( b) the maximum seasonal fish consumption rate provided in the NODA comments ( i. e., 393.8 g/ day). The results suggest that total IQ reductions under Option 1 and 2, even under these conservative assumptions ( i. e., highest change in mercury fish tissue concentrations under Option 1 and Option 2 and the highest seasonal fish consumption rate), are relatively low at 0.32 IQ points per child. This relatively low IQ benefit for this conservative scenario reflects the fact that, while states where the Chippewa are located may have relatively high absolute ( total) MeHg concentrations in target fish species, modeled EGU deposition over these areas is relatively low and consequently, CAMR is likely to produce relatively small changes in mercury fish tissue concentrations compared with other areas where EGU deposition is higher ( e. g., the Ohio river valley). These findings argue against a distributional equity concern for the Chippewa in this portion of the study area ( although this conclusion needs to be considered in the context of the overall precision and specificity of the benefits model used in this RIA which is not intended for site specific analysis and was developed for application at the regional level).

The National Research Council has identified fish consumption as the primary pathway of concern for exposure to methylmercury in the United States and consequently, the RIA has focused on this exposure pathway and has not considered other dietary categories such as nonfish meat and vegetables. EPA does recognize that additional dietary pathways may contribute to overall methylmercury exposure, however these pathways are likely to be overshadowed by the fish consumption pathway. Even in the case of subsistence sub populations who may obtain a significant amount of their protein and/ or calories from self produced food stuffs, fish is expected to represent the dominant methyl mercury source. In the case of ducks, although they may have methlymercury concentrations that match fish concentrations ( although as the commentor noted, these studies have limitations), because ducks are not likely to consume upper trophic level fish, their mercury levels are likely to be low compared with upper trophic 9 231 level ( predator) fish. For these reasons, EPA does not believe that significant uncertainty is introduced into either the primary benefits analysis, or consideration of distributional/ equity issues through exclusion of these non fish dietary pathways.

The RIA used measured mercury fish tissue data collected by both states ( National Listing of Fish Advisories) and the EPA ( National Fish Tissue Survey) and was not based on generalized data on mercury concentrations in commercial fish. While not providing complete coverage for all areas potentially fished by modeled populations including Native American populations such as the Chippewa, this fish tissue data set, does provide a reasonable degree of coverage for mercury fish tissue contamination in the context of conducting a benefits analysis. In the case of the Native American case study modeled for the RIA ( the Chippewa), exposure modeling was based on ( a) fish tissue concentrations for waterbodies in the potential fishing activity zone of the Chippewa in Michigan and Minnesota and ( b) fishing activity modeling that reflects reasonable assumptions regarding trip travel distances associated with fishing activity by the Chippewa. In other words, the benefits analysis was not based on generalized assumption regarding mercury contamination in commercial fish, but rather on measured mercury fish tissue concentrations measured in waterbodies likely accessed by this population.

Although EPA considers inclusion of the NFTS data extremely valuable in providing additional coverage for the study area, it is important to note that the majority of measured fish tissue concentrations were contributed by the NLFA and not by the NFTS. This fact partially addresses the commentor's concerns ( i. e., the benefits analysis primarily reflects NLFA data with a smaller relative contribution from the NFTS dataset). EPA agrees with the commentor that NLFA data ( when reflecting areas of increased fishing activity) would be preferable to randomly collected data for purposes of supporting a benefits analysis. However, given the patchy nature of the NLFA and the variety of sampling protocols used by different states in collecting data included in the NLFA, EPA considers the NFTS data to be very useful in filling in gaps in coverages and in providing a consistent randomly sampled dataset to augment the purposively sampled data contained in the NLFA.

Comment:

One commenter ( OAR 2002 0056 5423) presents an important source of information. Figure K1 shows the distribution of hair Hg values of 56 pregnant women sampled from 12 different native communities across Alaska. This 2002 survey by the State of Alaska Epidemiology Office confirms that on average Alaskan native pregnant women ( with a mean hair Hg value of 0.6 ppm) consumed more fish than other average U. S. women ( who have a mean hair Hg value of about 0.2 ppm based on the ongoing CDC's NHANES database). It is also clear from Figure K1 ( see e docket OAR 2002 0056 5423), based on the examination of 8 Aleutian mummies dated to about 550 years ago, that the native Alaskans had long been naturally exposed to significantly large levels of MeHg through fish and marine mammals in their traditional diets without any plausible " contamination" by power plant Hg emissions.

Exposure to MeHg in Alaska: Today Versus 550 Years Ago. Today's distribution with a 9 232 mean of 0.6 ppm. Compare 0.6 ppm to the mean level of MeHg in 550 year old with one mummy with MeHg as high as 4.6 ppm. Aleutian mummies: 1.2 ppm ( mean of 4 adults) 1.44 ppm ( mean of 4 infants). State of Alaska Epidemiology Bulletin No. 29( December 11, 2002).

Regarding other native populations in Eastern North America, field records from Nunavik, Quebec ( Figure K2, see e docket OAR 2002 0056 5423) suggest that the prenatal exposure level of MeHg, lead and persistent organic pollutants ( or POPs) in Inuit infants born between 1994 and 2001 has declined significantly. The authors of this new research paper concluded that " A significant reduction of lead and Hg concentrations was found, but there was no clear linear or exponential trend. The decreases observed could be explained by a decrease in food contamination, by changes in dietary habits, or, most likely by a combination of both. Although questions remain as to the exact causes of decline, it is encouraging to observe such an improvement in prenatal exposure for this highly exposed population."

Concentrations of Hg, lead and persistent organic pollutants in umbilical cord blood of Inuit infants born in Nunavik, Quebec have been decreasing from 1994 to 2001 " A significant reduction of lead and Hg concentrations was found, but there was no clear linear or exponential trend. The decreases observed could be explained by a decrease in food contamination, by changes in dietary habits, or, most likely by a combination of both. Although questions remain as to the exact causes of decline, it is encouraging to observe such an improvement in prenatal exposure for this highly exposed population."

Equally important are explanations and cautions from this team of Laval University Medical Center researchers in an earlier publication ( Dewailly et. al., 2001, Archives of Environmental Health, vol. 56, 350 357):

" According to recommendations formulated by the World Health Organization ( WHO), no more than 5 percent of individuals in a population should display a methylmercury concentration that exceeds 1000 nmol/ L [ or converted to 200

g/ L MeHg in blood]. Concentrations of total mercury noted in present study did not exceed 560 nmol/ L [ 112

g/ L]. WHO issued more stringent recommendations for pregnant women, stating that not more than 5 percent of this subgroup should exhibit methylmercury concentration above 400 nmol/ L [ 80

g/ L]. In our survey, no women of childbearing age exhibited concentrations of this magnitude. Recent data from Faroe Island suggest that the neurologic status of children can be affected by low level prenatal exposure to mercury. There are, however, major differences between the diet of Faroese and the diet of Inuits, and care must be exerted before one concludes that Inuit children are at risk. [ I] n view of the high selenium intake [ in the diets of the Inuit population from consumption of mattak ( beluga whale skin) which is about 2.4 times higher than that measured in the Farose], which may counteract methylmercury induced toxicity, local public health authorities did not recommend reducing seafood consumption."

If EPA has serious concerns for native populations, it should focus on the fact that instead of advancing health and safety for these peoples, Hg warnings are already causing harm. John 9 233 Middaugh, State Epidemiologist of Alaska, recently warned FDA:

" Advisories based upon risk assessment without consideration of well established public health benefits of fish consumption have great potential to harm public health if reductions in fish consumption occur."

Middaugh reported that many native Alaskan communities abandoned traditional fish diets since the FDA's 2001 Hg advisory, with a subsequent increase in diabetes, heart disease, and vitamin A and D deficiencies.

Response:

As described in other responses, the Agency has high confidence in the RfD for methylmercury. EPA encourages the public to vary the species and sources of fish in order to obtain the benefits of fish consumption while avoiding elevated exposures to methylmercury. The fish advisory developed jointly with the Food and Drug Administration emphasizes the benefits of including fish in a healthy diet while informing the public on ways to reduce methylmercury exposure ( http:// www. epa. gov/ waterscience/ fishadvice/ advice. html).

Comment:

One commenter ( OAR 2002 0056 5423) supports EPA's intention to properly apply information from the ongoing CDC's NHANES database ( which some at EPA have not done), but must stress that no women ( Figure L1, see e docket OAR 2002 0056 5423) or children ( Figure L2, see e docket OAR 2002 0056 5423) in the current NHANES survey are actually harmed by the levels of Hg in their blood from fish consumption.

The commenter will delay comments on the ultra conservative nature of the MeHg RfD value set by EPA, as shown in Figures L1 and L2, to comment ( O) ( see e docket OAR 2002 0056 5423). The commenter will also confirm in comment ( O) that EPA's MeHg RfD was derived from the Faroe Islands Children Study that was plagued by contaminants like PCBs and DDT through consumption of pilot whale products and hence is widely recognized in professional circles as incompatible with or irrelevant to the U. S. consumption profile of a wide variety of fish ( i. e., excluding whale products).

Response:

In deriving the reference dose for methylmercury, EPA relied on an integrated analysis involving three studies. These longitudinal, developmental studies were conducted in the Seychelles Islands, the Faroe Islands, and New Zealand. The Seychelles study yielded scant evidence of impairment related to in utero methylmercury exposure, whereas the other two studies found dose related effects on a number of neuropsychological endpoints. In the assessment developed for the RfD, emphasis is placed on the results of the Faroe Islands study, the larger of the two studies that identified methylmercury related developmental neurotoxicity. 9 234 Supporting evidence from the New Zealand study provides assurance that choosing this focus is the appropriate strategy for protecting public health. Conclusions from the National Research Council review of methylmercury support this use of the Faroes Island study and disagree with the suggestion of a role for PCBs in the neurological effects observed ( NRC. 2000. Toxicological Effects of Methylmercury. National Academy Press.), saying that " The committee concludes that there do not appear to be any serious flaws in the design and conduct of the Seychelles Islands, Faroe Islands, and New Zealand studies that would preclude their use in a risk assessment."

The Agency's derivation of the RfD also followed the National Research Council recommendation for an overall composite uncertainty factor of no less than 10.

In summary, the Agency's overall confidence in this RfD assessment is high. Three high quality epidemiological studies published since the last derivation of the oral RfD in 1995, have been included in the analysis. Two of the studies ( Faroe Islands, New Zealand) reported effects on a number of neuropsychological endpoints, whereas the third ( Seychelles Islands) reported no effects related to in utero exposure to methylmercury. Benchmark dose analysis of a number of endpoints from both the New Zealand and Faroe Islands study converged on an RfD of 0.1 µ g/ kg day, as did the integrative analysis combining all three studies. Although there was coexposure to PCBs in the Faroe Islands study, statistical analysis indicated that the effects of PCBs and methylmercury were independent. Moreover, benchmark dose analysis of the endpoints that were significantly associated with methylmercury yielded RfDs that were approximately the same when corrected for PCBs. The same was true when the analysis was or based on the subset of the cohort in the lowest tertile with respect to PCB levels, as compared with the full cohort. These findings provide further evidence that the identified effects are in fact the result of methylmercury exposure.

Comment:

The commenter ( OAR 2002 0056 5460) stated that with regard to step four of the proposed revised benefits assessment methodology, EPA has not adequately explained how it intends to supplement data from the National Listing of Fish Advisories with data from the National Study of Chemical Residues in Lake Fish Tissue, let alone why such supplementation is necessary. The commenter added that EPA has likewise failed to explain why it is appropriate to develop, in the context of the CAMR, national estimates of the mean concentrations of 268 chemicals in fish tissue from lakes and reservoirs across the U. S. The commenter stated that EPA should not use national estimates to underestimate Hg concentrations, or Hg exposure, in any particular region or area of the country.

Response:

The benefits analysis completed for the RIA is not intended to model local scale changes in fish tissue concentrations and exposures in support of site specific risk analysis. Instead, 9 235 modeling conducted for the RIA is intended to capture generalized regional changes in methlmercury exposure resulting from reductions in power plant mercury emissions in order to support a national scale benefits assessment focusing on the 37 State eastern US study area. For additional details on the benefits analysis modeling framework see Section 10 of the RIA.

Although EPA is not conducting local scale modeling of mercury fish tissue concentration changes resulting from decreased mercury deposition, the modeling framework used in this RIA is believed to have sufficient precision to generate reasonably accurate benefits estimates. Specifically, 36km2 CMAQ grid cell air modeling results are used to project deposition changes over individual fish tissue sampling locations for purposes of predicting changes in fish tissue concentrations related to emissions reductions from power plants. In addition, recreational anglers and additional potential high exposure populations ( e. g., highend consumers and Chippewa) are modeled using relatively spatially differentiated behavioral and exposure models which consider both the distribution of fishers across the study area ( at the US Census block group, or 8 digit HUC level) and the potential behavior of fishers in accessing different areas or zones for fishing. This modeling framework is believed to provide sufficient spatial resolution in characterizing regional patterns of population level exposure to mercury through fishing activity ( and consumption) to support the benefits analysis. For additional detail on the benefits modeling framework, see Section 10 of the RIA.

Although EPA considers inclusion of the NFTS data extremely valuable in providing additional coverage for the study area, it is important to note that the majority of measured fish tissue concentrations were contributed by the NLFA and not by the NFTS. This fact partially addresses the commentor's concerns ( i. e., the benefits analysis primarily reflects NLFA data with a smaller relative contribution from the NFTS dataset). EPA agrees with the commentor that NLFA data ( when reflecting areas of increased fishing activity) would be preferable to randomly collected data for purposes of supporting a benefits analysis. However, given the patchy nature of the NLFA and the variety of sampling protocols used by different states in collecting data included in the NLFA, EPA considers the NFTS data to be very useful in filling in gaps in coverages and in providing a consistent randomly sampled dataset to augment the purposively sampled data contained in the NLFA.

The procedure used to generate a single standardized fish tissue dataset for use in supporting the benefits analysis using data from both the NLFA and NFTS datasets is described in the CAMR RIA. Regarding the rationale for combining the two datasets, EPA believes that the NLFA provides a large number of fish tissue samples with some bias for areas likely fished ( which is advantageous in supporting the benefits analysis), while the NFTS, with its statistically random sampling strategy, provides consistent spatial coverage for waterbodies across the study area and in that way, can fill in gaps left by the NLFA.

Comment:

One commenter ( OAR 2002 0056 5497) stated that the development of an assessment protocol that melds regional fish consumption patterns with the distribution of MeHg 9 236 concentrations in fish is an immensely challenging and complex undertaking. Existing fish tissue samples must be normalized to account for differences in fish age, length, etc. Fish consumption data must be developed at the regional level to reflect differences in the types of species consumed, the source of those fish ( including whether they come from highly productive waterbodies or not)" and the amount of fish consumed. The commenter does not see how the analyses described in Step 4 could be completed, in any scientifically valid way, by March 15, 2005.

EPA's request for comments on the incorporation of the National Listing of Fish Advisories' ( NLF A) and National Fish Tissue Study's ( NFTS) fish tissue data into the National Descriptive Model of Mercury and Fish Tissue ( NDMMFT) suffers from EPA's failure to make the pertinent material available in the docket. EPA's promise to place these materials in the docket " when available" makes it difficult, if not impossible, to respond to EPA's questions in a detailed manner. EPA should not use NDMMFT in a benefits analysis without further public comment.

As for the fish consumption rates incorporated into EPA's MeHg fish tissue criterion, they are conservative. The default consumption rate of 17.5 grams/ day is based on a value representing the 90th percentile of the value for freshwater and estuarine fish from a 1995 96 study conducted by the Department of Agriculture. Default fish intake rates for recreational and subsistence fishers of 17.5 grams/ day and 142.4 grams/ day respectively are based on values representative of the 90th and 99th percentiles of the general population. The fish tissue criterion is designed to be highly protective, not to accurately predict fish consumption rates in a way that would be realistic for a benefits analysis.

Response:

EPA has implemented a methodology for the RIA that accomplishes most of the technical tasks noted by the commenter. For the RIA, EPA has used the NDMMFT statistical model to effective standardize the measured fish tissue concentrations with regard to size ( length) and species. This produces a standardized ( diet relevant) set of fish species and lengths for use in the benefits analysis and avoids the inclusion of non diet relevant sizes/ species in exposure modeling. Regarding fish consumption rates, EPA acknowledges that regional differences are likely to exist both for recreational anglers as well as high consumption ( subsistence) populations. However, with regard to recreational anglers, EPA could not identify regional or local scale studies in the literature with sufficient collective coverage to allow comprehensive modeling of the 37 State study area without leaving large gaps in geographic coverage ( i. e., individual studies covering smaller geographic areas or watersheds were identified, but they could not be combined to provide a cohesive coverage for the study area). Ultimately, the consumption rates for the recreational angler that were used in the RIA were obtained from peer reviewed studies and are representative of general trends in behavior for this group. For special populations ( i. e., the Chippewa and Hmong), consumption rates based on peer reviewed studies focusing on these specific ethnic groups were used. The RIA contains an expanded description of our application of the NDMMF. More information about the model itself can be 9 237 found at http:// pubs. water. usgs. gov/ sir20045199/.

5. Step 5: Assessing the relationship between reductions in human exposure and improvements in public health. EPA sought comment on all aspects of its proposed revised methodology for estimating the relationship between reductions in methylmercury exposure and improvements in health. In particular, EPA sought comment on: ( 1) the focus on neurodevelopment health of children; ( 2) the selection of IQ as an endpoint for quantification of neurodevelopmental effects and whether it is an appropriate endpoint for benefits analysis; ( 3) whether other neurodevelopmental effects can be quantified and are amendable to economic valuation; ( 4) whether, and if so how, data from the Faroe Islands, New Zealand, and Seychelles Islands studies can be integrated for the benefits analysis; the choice of the K= 1 model for estimating the relationship between exposure and IQ and practical alternatives to that approach; and the appropriateness of using a linear dose response model given the EPA's reference dose, which assumes a threshold does below which there is not likely to be an appreciable risk of deleterious effects during a lifetime.

Comment:

The commenter ( OAR 2002 0056 5542) has historically been united in its advocacy that federal regulatory agencies such as the EPA must use sound science and risk prioritization. The commenter has supported " scientifically sound risk analysis; risk based prioritization; benefit cost analysis; flexible, efficient, cost effective risk management; and public participation in all phases of the process." The commenters stated that their policy also expressly supports a conclusion made by EPA in its document, " Reducing Risk: Setting Priorities and Strategies for Environmental Protection, 2 September 1990," which states:

There are heavy costs involved if society fails to set environmental priorities based on risk. If finite resources are expended on lower priority problems, at the expense of higher priority risks, then society will face needlessly high risks. If the priorities are established based on the greatest opportunities to reduce risk, total risk will be reduced in a more efficient way, lessening threats to both public health and local and global ecosystems.

The commenter was concerned that the EPA is chasing a Hg emissions reduction goal that is a low priority problem that represents little or no risk, but would nevertheless be squandering finite economic resources that are needed for economic growth and for meeting higher priority risks. Since the EPA's Hg decisions could have the effect of dramatically reducing coal use in the U. S., generators trying to fulfill the nation's growing need for electricity would then be forced from abundant coal to either scarce natural gas or future nuclear power.

The commenter noted that the current EPA has access to almost a decade more research regarding both the real science of public health exposure to U. S. power plant emissions of 9 238 elemental Hg and to the net public health benefits of eating fish, the primary source of Hg accumulation in the body. The commenter believed that the EPA must correct the refuted science that was the foundation of the Agency's reference dose, and therefore the foundation of the agency's proposed Hg rule.

Under the sound science category, the commenter believed the central issues for the agency are whether any level of MeHg consumption by humans was acceptable; and whether reducing elemental Hg emissions from U. S. power plants will have any measurable impact on the MeHg levels in fish broadly consumed by the American public. Many epidemiological studies have been undertaken since the EPA first picked its reference dose level that show almost uniformly that some levels of MeHg in humans are acceptable. Further, natural levels of MeHg, as well as the deposition of elemental Hg from sources outside the U. S., ensure that even closing U. S. coal fired power plants will not affect the quantities of MeHg in fish that the U. S. population ingests.

As carefully documented in the comments filed by the Utility Air Regulatory Group ( URAG) on June 29, 2004, the EPA made a number of serious procedural mistakes and deviations from its customary and or appropriate processes in order to conclude that Hg emissions from coal fired power plants were adversely affecting public health. The nation is facing many real risks of terrorism and natural events, such as infectious diseases, hurricanes, volcanoes or tsunamis. Manufacturers in particular are facing intense and sometimes unfair international competition and escalating structural costs at home from an out of control legal system, skyrocketing pensions and health benefit costs, high corporate taxation, high energy costs and over zealous regulation. The nation, and certainly the manufacturing sector ( which still accounts for 13 percent of the U. S. economy), can ill afford expensive regulations promulgated in order to chase minor or negative net risks to public health.

The EPA itself has stated that there is a reference dose level of MeHg in the body " below which there is no danger to human health." Other entities, including the World Health Organization, the U. S. Federal Food and Drug Administration ( FDA), the Agency for Toxic Substances and Disease Registry ( ATSDR), Health Canada ( Canada's FDA) and the U. K. Committee on Toxicity in Chemicals in Food have all picked levels at which MeHg in the body is not harmful, and the threshold levels set by each organization are well above the EPA's recommended level. In other words, the EPA has not only picked an unnecessarily low level of human exposure compared to five other U. S. and international organizations, but it now appears that the agency is suggesting that there is no dose of MeHg that is safe. If that is what the EPA is now concluding, it is not only contrary to all existing scientific evidence, including the on going analysis of the value of selenium in countering MeHg exposure, it constitutes a tragic application of the easily abused precautionary principle. Moreover, how is the EPA proposing to measure the positive health impact of the Hg reductions it is proposing? If the EPA discovers that there is no measurable positive impact from its new rules, would the EPA then rescind its regulations?

Only by declaring that there is no safe dose of MeHg can the EPA justify reducing emissions from U. S. power plants. This is because there is ample evidence to show that elemental 9 239 Hg emissions from U. S. power plants are a very small percentage of the elemental Hg falling onto U. S. soil and waters. Further, there is ample evidence, submitted in detailed comments by the Center for Science and Public Policy and others to this NODA, that MeHg levels in fish and humans who eat them have remained constant since before the industrial revolution and subsequent abundant coal use. In defending its position that reducing Hg emissions from power plants will result in lower MeHg levels in fish, the EPA has given some weight to the Florida Mercury Report of Nov. 6, 2002, regarding MeHg changes in fish in the Everglades during the 1990' s after Hg emission controls were placed on waste incinerators in the area. However, the assumptions of this study have been challenged. ( See " A Framework for Assessing the Cost Effectiveness of Electric Power Sector Mercury Control Policies", PERI, May 2003. [ In a press release issued on November 13, 2003, PERI observed that the Everglades study is flawed in several material ways, including by not recognizing substantial differences between incinerator and power plant emissions.)

If the EPA determines that there is no safe Hg level, then the agency must either order a ban on all fish or eliminate all sources   natural and anthropogenic   of elemental Hg into the environment. Of course, it is impossible to eliminate Hg that is transported in the air from Asia, that naturally exists in the soil and oceans, and that is emitted from forest fires and volcanoes. Merely regulating one very small part of the Hg cycle U. S. power plants   would do little if anything to protect human health from exposure to MeHg from fish. Accordingly, a ban on eating fish would be the only logical outcome of a policy driven by a belief that there is no safe Hg level.

The EPA has an opportunity to correct the health science record before the agency puts its full reputation as the protector of public health behind staff opinions that are now based on refuted, discredited, decade old studies, including the Faroe Island study. It is now clear that the Faroe Island study was discredited after the original EPA analysis and after the National Research Council study of 2000, both of which the EPA is currently relying on to justify its proposed reference dose.

The commenter either supported the fishing industry or were in the fish processing industry. These companies are severely affected by any scare mongering that frightens Americans away from eating fish as part of their diet. For a detailed analysis of the net harm of scaring people away from eating fish, including the loss of net pregnancy and net cardiovascular benefits, see the comments being submitted on this NODA by the Center for Science and Public Policy. The Center for Science and Public Policy also provides analysis of the deficiencies and failings of several studies that find negative cardiovascular effects from consuming MeHg from fish. The EPA also should recognize that The Institute of Medicine is going to do a two year study of the benefits of fish consumption, which could embarrass any EPA actions that have resulted in driving people away from fish consumption for no measurable health benefit.

The commenter added that any EPA analysis must consider other risks to public health that occur when electricity and natural gas prices skyrocket as a consequence of excessive EPA regulation of coal fired electric generation. Clearly, additional costs on manufactures will continue to erode the manufacturing employment base in this country as they struggle to compete 9 240 with low cost foreign manufacturers. However, not only are manufacturing jobs at risk   and the higher compensation, better health care and pension plans that manufacturing workers enjoy compared to the rest of the economy   but so are risks associated with a lower tax bases that is the result of having a weak manufacturing sector, which would lead to lower public services, including health clinics. A weak manufacturing sector and high electricity costs will sap the investment markets upon which millions of current and potential retirees depend. Finally, dramatically increasing the costs of electricity and natural gas prices paid by homeowners must be recognized as harming many economically disadvantaged people, who have the least capacity to absorb these additional costs.

Thus, the EPA's actions to regulate Hg emissions have the significant  and so far unaccounted for by the EPA  potential for harming public health that must be weighed against the minuscule benefits of regulating elemental Hg emissions from U. S. coal based power plants.

Response:

Please see the RIA as well as the Revision of December 2000 Regulatory Finding on the Emissions of Hazardous Air Pollutants from Electric Utility Steam Generating Units and the Removal of Coal and Oil fired Electric Utility Steam Generating Units from the Section 112( c) List for a discussion of the Agency's rationale for not proceeding under Section 112 Notice and in the Technical Support Document: Methodology Used to Generate Deposition, Fish Tissue Methylmercury Concentrations, and Exposure for Determining Effectiveness of Utility Emission Controls in the docket.

Comment:

One commenter ( OAR 2002 0056 5556) noted that the EPA need not limit its benefits analysis to any single quantifiable health benefit but rather should consider all pertinent anticipated benefits to human health. It may be especially important to include a discussion on the benefits to adult cardiovascular health as this effect has been correlated with MeHg exposures at or below levels associated with neurodevelopmental effects ( Toxicological Effects of Methylmercury, National Academy of Sciences, 2003). This commenter stated that it is also important to include any expected improvements in water quality and subsequent reductions of MeHg in fish tissue, realizing that a reduction in Hg emissions of at least 75 percent may be required before measurable environmental impacts can be detected.

Response:

EPA recognizes that research is ongoing in a number of areas related to both mortality and morbidity in relation to methylmercury exposure. However, at the time of this regulation, existing peer reviewed evidence was not considered sufficiently conclusive to include these additional health endpoints in the primary benefits analysis and EPA has focused on reductions in IQ resulting from prenatal exposure in estimating health related benefits. See Appendix B for a detailed discussion of the current status of research involving the mortality endpoint for 9 241 methylmercury exposure.

Comment:

One commenter ( OAR 2002 0056 5471) referenced comments on the Proposed Rule that supports the control of Hg from coal fired EUSGUs through a cap and trade program. However, for the ultimate rule to establish a regulatory program that reflects a reasonable estimate of benefits from Hg emission reductions, this commenter believes that EPA must assign to EUSGU Hg emissions only those health risks that can be traced to those emissions.

In the preamble to the Proposed Rule, the Agency claimed that substantial benefits would result from the proposed CAMR. But the claimed benefits are based almost entirely on the value of estimated health benefits from the decline in ambient PM 2.5 caused by the SO 2 and NOx reductions resulting from the control measures required to reduce Hg emissions ( primarily SO 2 scrubbers and selective catalytic reduction ( SCR)). Because the Proposed Rule relied almost exclusively on these co benefits of the proposed regulatory control of Hg, this commenter stated that no health benefits were directly associated with reductions in Hg emissions. The Agency's intention in the NODA, at least in part, appears to be to develop a methodology to better quantify benefits attributable to the proposed CAMR by isolating the benefits of Hg emissions reductions from those benefits associated with SO 2 and NOx emission reductions. While this commenter supports the Agency's undertaking of the additional analysis, EPA's proposed approach to assessing the benefits of Hg emissions reductions creates a danger of overestimation of those benefits.

Response:

EPA has developed a benefits analysis methodology for this RIA that is designed to provide unbiased estimates of health related benefits resulting from regulatory options considered under CAMR. In keeping with convention, efforts have been made to use peerreviewed methods and data sets when available and to avoid introducing conservative assumptions at all stages in the benefits modeling process. EPA's emphasis on representativeness has meant that a number of health endpoints, that may ultimately be supported by research findings ( e. g., cardiovascular related mortality and immunologic related morbidity), have been excluded from the primary analysis in order to include only those endpoints in the formal benefits analysis for which there is strong peer reviewed support. For additional details on the modeling framework including all key assumptions and input datasets, please review Chapter 10 in the RIA.

Comment:

One commenter ( OAR 2002 0056 5471) noted that in the NODA, EPA requests general comments on analytical approaches to translating estimates of reductions in Hg emissions from EUSGUs into approximate health outcomes in humans. It has been suggested that one guide for this analysis is the Agency's regulation of lead. In the late 1970s, EPA initiated a successful 9 242 program designed to eliminate all lead emissions into the environment primarily through the phase out of leaded gasoline. Since airborne lead emissions are linked to blood lead levels in children and related neurological impacts, it may appear reasonable to utilize the lead elimination model for dealing with Hg.

However, this commenter believes there are significant differences between the nature of lead emissions and EUSGU Hg emissions and the health benefits reasonably associated with reducing those emissions. If these differences are not taken into account, the commenter believes that blindly making assumptions for Hg emissions reductions based on the Agency's experience with lead will cause EPA to overestimate the benefits of Hg emissions reductions. First, virtually all airborne lead is attributed to anthropogenic sources while a large percentage of airborne Hg ( greater than 50 percent) is due to natural sources. Thus, while the Agency acted reasonably in targeting all lead emissions, it is impossible to eliminate all airborne Hg emissions. Second, lead emissions and ambient lead concentrations are primarily associated with urban areas while Hg emissions and ambient Hg concentration are widespread on a global scale. Third, while there appears to be no lower limit for neurological impacts for lead blood levels, Hg blood levels have a clear threshold below which there are no neurological impacts. Fourth, while neurological impacts were clearly shown at blood lead levels present in children in U. S. urban areas in the 1970s, no such neurological impacts have been noted or documented at Hg blood levels currently found in child bearing age women or children in the U. S.

Comment:

One commenter ( OAR 2002 0056 5471) noted that in explaining Step 5 of its revised benefits analysis, EPA seeks comment on its proposed use of three studies, including a study from the Faroe Islands, to estimate the relationship between reductions in MeHg exposure and improvements in health and its proposed use of intelligence quotient ( IQ) decrements associated with prenatal MeHg exposure to quantify and value the health benefits of reduced exposure to MeHg.

EPA has selected a reference dose ( RID) for Hg in maternal blood ( 5.8 ppb) that serves as a de facto threshold. This number, which is 10 times below the threshold number developed from the Faroe Islands study and 14 times lower than the World Health Organization's level of concern, is very conservative. This commenter believes that if an unrealistically low threshold for Hg blood levels were used to estimate benefits, reductions in blood levels between the true threshold and the unrealistically low one would create the appearance of a benefit where there is none.

The commenter stated that the danger of using the RID as the benchmark for assuming benefits is revealed by EPA's proposal to develop a relationship between Hg emissions and general population IQ. There is no evidence of IQ impact at blood Hg levels greater than the RID but below the Faroe Island threshold level. Yet, if this relationship were then coupled with an imputed value for increased IQ for the general population, large estimated benefits could be generated that would not exist. Likewise, if EPA's proposed assumption of a linear response 9 243 between blood Hg levels and IQ would lead to an imputed benefit for reducing blood Hg below the threshold level, the Agency would be creating benefits that do not exist.

While the commenter does not support all the findings of the Faroe Islands study, the study provides a minimum threshold for blood Hg levels. This commenter recommends that the Agency use at least the threshold level established in that study ( if not a higher one, such as the WHO level of concern), and not the RID, as the benchmark for measuring health benefits.

Response:

Please see Chapters 10 and 11 of the RIA for a discussion of the CAMR benefits.

Comment:

One commenter ( OAR 2002 0056 5476) commented on Step 5 of the NODA addressing cost/ benefit analyses and how reduction will improve human health. The commenter finds that EPA's benefits analysis does nothing to address the importance of fishing as a cultural practice. There is no way to place a dollar amount on the benefit to spiritual well being as a result of practicing a centuries old tradition and passing it on to our children. In a more concrete measurement, EPA does nothing to address replacing a subsistence food source that provides a significant amount of nutrition for our Band members. In making a local, easily obtainable food source inedible due to poisoning, EPA should calculate the costs that will be incurred in cleaning up these toxins to improve the health and physical well being of the people and the health of the environment for today's and future generations. The commenter was also unaware of any attempts EPA has made to quantify the costs of the learning and educational problems that exposed children may experience. For example, the loss in lifetime earnings resulting from retardation of mental aptitude in the generalized population as a result of Hg poisoning has been estimated at $ 2.3 billion per year. By refusing to set adequate MACT standards, EPA is shifting this economic burden onto the heads of indigenous people and their communities as a whole. Another error in the EPA's cost/ benefit analysis comes from the projection of $ 15 billion in savings due to health related benefits from its proposed rule when forecasted against the do nothing option. These are simply health benefits that accrue from EPA's very substandard proposal. The commenter believes that if the more stringent MACT standard were set in place, additional billions of dollars could be saved.

This commenter believes that EPA has also failed to assess tourism related impacts. Tourism in $ 9.8 billion annually in Minnesota alone. Of this total, sport enthusiasts spend $ 1.58 billion, or 16 percent. Locally, Lake Mille Lacs universally recognized as a premier trophy fishing lake and its Lake related tourism adds an estimated $ 150 million into the local economy annually. Although it is unknown to what level fish advisories impact these number, fishing and tourism bring in income that the State of Minnesota cannot afford to lose. The other Great Lakes states of Wisconsin, Michigan, Illinois, Indiana, and Ohio face similar situations. Together, these States, along with Minnesota, attract 7.8 million anglers annually who spend $ 5 billion in fishing related dollars. Although these are not directly health related issues, they certainly need to be addressed 9 244 in EPA's economic considerations.

The commenter also takes issue with the modeling performed in the analysis. The commenter does not believe the science of modeling is at a state where it can accurately be used for Hg due to the lack of understanding about dry deposition. Currently among many ambient air monitoring personnel, there is a strong opinion that there are too few dry deposition monitors in the North American continent and barely adequate network of wet deposition monitors in the eastern half of the U. S., with very little of either monitors existing on Anishinaabewaki ( Indian Country) so it is very hard to say how much wet or dry deposition of Hg is occurring in these areas. Based on this concern, the commenter believes it is not in the Band's interest to propose a cap and trade program relying on the results of EPA's models. In turn, the commenter asks the EPA to uphold its Trust responsibility obligations by erring on the side of caution rather than be wrong in such an important matter. To account for the lack of confidence in the models, EPA should abandon its idea of cap and trade and cleave to a MACT standard.

The commenter believes that the National Emissions Inventories used in EPA's analysis probably underestimated the amount of Hg emitted from some sources, especially in the western and central regions of the U. S., such as miscellaneous product disposal. EPA has used the best information it has available, but it should leave a margin of safety to account for inaccuracies.

The commenter believes there is a MACT calculation problem. The EPA seems to have followed a methodology recommended by a utility trade group, using a short term worst case analysis to develop a long term average standard. This method used only the 2.5 percent worst emissions from relevant sources, ignoring the 97.5 percent best emission reductions.

The commenter would like to reference the excellent comment letter by the Forest County Potawatomi Community ( FCPC ) to EPA on the Mercury Utility Rule ( US EPA Document ID No. OAR 2002 0056 2173, April 27, 2004). The experts retained by the FCPC stated in attachments to that letter why EPA's proposed MACT standards are unacceptable and why EPA improperly failed to consider alternate methods of removal, such as activated carbon injection. The commenter is unable to make specific comments on these issues as time is running short. The commenter also believes that it cannot add anything to the discussion that has not already been said in the FCPC letter.

In studying Table 1 of the Notice of Data Availability, it appears that it really is not much more expensive to control emissions of 7.5 tons per year rather than of 15 tons per year. A two phase cap of 15 tons is projected to cost $ 3.3 billion by 2010 and $ 6.7 billion by 2020. But a two phase cap of 7.5 tons is expected to cost $ 4.6 billion by 2010 and $ 7.1 billion by 2020. The difference by 2020 is only 6 percent! Even with all of EPA's incomplete assumptions that lead to faulty calculations and failure to carry out a proper MACT determination, it only makes a 6 percent difference in cost.

Though most of the Band members are oblivious to any of EPA's calculations or rule making, among those of us in Tribal Government who are entrusted and statutally obligated 9 245 to protect the health of our Band members and the health of the natural resources available to the Band members, or to our Band members who actively seek to information, it would be hard to over state the level of utter disbelief expressed across Anishinaabewaki over the way EPA has handled this rule making.

Response:

EPA has used a cost of illness function based on lost earnings resulting from methylmercury exposure as the basis for its primary benefits estimate in the RIA ( i. e., prenatal methylmercury exposure through maternal consumption producing IQ decrements in children which translate into lost earnings later in life). This valuation function, which is based on the approach used in past EPA regulations concerning lead exposure, also considers the impact of lowered IQ on years of education achieved. EPA acknowledges that because this function is based on cost of illness and not willingness to pay ( WTP), it likely represents a lower bound for valuation of the IQ decrements and that a more comprehensive WTP based function would capture other factors such as those listed by the commentor above. Note, EPA did not use a WTP based function in the benefits analysis because peer reviewed literature does not support derivation of such a function at this time.

Comment:

One commenter ( OAR 2002 0056 5517) notes that the NODA fails to provide a scientifically sound reason as to why EPA adds a factor of ten safety factor in calculating what is an acceptable daily intake of MeHg from eating fish. Adding such a safety factor is usually done to account for how sensitive populations, such as children, who are believed to be more sensitive to MeHg than adults, differ in response to the general population.

This commenter points out that the reason the additional safety factor, as used by EPA, is questionable is that the available studies of the health effects of MeHg exposures focus both on healthy and sensitive subpopulations inclusively, thus their particular susceptibilities are already accounted for, obviating the need for any added safety factor. EPA has provided no information in this NODA that would justify the inclusion of the factor of ten safety factor used by the agency; as such its use is clearly arbitrary and capricious. Moreover, there is no explicit statutory authority in the Clean Air Act that mandates the use of such a safety factor.

In their comments to EPA concerning the agency's proposed rule to control emissions of Hg from coal fired power plants, other national trade associations have also addressed the questionable safety factor used by EPA in establishing what is an acceptable daily intake of MeHg from eating fish. These organizations also find that the use of the factor of ten safety factor is not justified. The commenter believes that its observations have merit and must be given careful consideration.

Response: 9 246 In deriving the reference dose for methylmercury, EPA relied on an integrated analysis involving three studies. These longitudinal, developmental studies were conducted in the Seychelles Islands, the Faroe Islands, and New Zealand. The Seychelles study yielded scant evidence of impairment related to in utero methylmercury exposure, whereas the other two studies found dose related effects on a number of neuropsychological endpoints. In the assessment developed for the RfD, emphasis is placed on the results of the Faroe Islands study, the larger of the two studies that identified methylmercury related developmental neurotoxicity. Supporting evidence from the New Zealand study provides assurance that choosing this focus is the appropriate strategy for protecting public health. Conclusions from the National Research Council review of methylmercury support this use of the Faroes Island study and disagree with the suggestion of a role for PCBs in the neurological effects observed ( NRC. 2000. Toxicological Effects of Methylmercury. National Academy Press.), saying that " The committee concludes that there do not appear to be any serious flaws in the design and conduct of the Seychelles Islands, Faroe Islands, and New Zealand studies that would preclude their use in a risk assessment."

The Agency's derivation of the RfD also followed the National Research Council recommendation for an overall composite uncertainty factor of no less than 10.

In summary, the Agency's overall confidence in this RfD assessment is high. Three high quality epidemiological studies published since the last derivation of the oral RfD in 1995, have been included in the analysis. Two of the studies ( Faroe Islands, New Zealand) reported effects on a number of neuropsychological endpoints, whereas the third ( Seychelles Islands) reported no effects related to in utero exposure to methylmercury. Benchmark dose analysis of a number of endpoints from both the New Zealand and Faroe Islands study converged on an RfD of 0.1 µ g/ kg day, as did the integrative analysis combining all three studies. Although there was coexposure to PCBs in the Faroe Islands study, statistical analysis indicated that the effects of PCBs and methylmercury were independent. Moreover, benchmark dose analysis of the endpoints that were significantly associated with methylmercury yielded RfDs that were approximately the same when corrected for PCBs. The same was true when the analysis was or based on the subset of the cohort in the lowest tertile with respect to PCB levels, as compared with the full cohort. These findings provide further evidence that the identified effects are in fact the result of methylmercury exposure.

Comment: