Fish and Wildlife Advisory News - March 2003

Recent Advisory News

• Pennsylvania Fish Consumption Advisory Updated - On February 24th, officials from the Commonwealth of Pennsylvania released the update of their 2003 sport fish consumption advisories. The update advises consumers that all sport fish in Pennsylvania should be consumed no more frequently than one-meal-per-week. In addition to the statewide advisory, Pennsylvania also has issued four other types of consumption advisories: two meals per month; one meal per month; one meal every two months; or do not eat. The state considers one meal to be equivalent to one-half pound of fish for a 150-pound person. The fish advisories do not apply to fish raised in commercial fish hatcheries or purchased in supermarkets, fish markets or restaurants. Pennsylvania is the only state to annually test its state hatchery-reared trout and to provide consumption advice using the Great Lakes Consumption Advisory Protocols. For this year (2003), trout stocked from state fish hatcheries are subject to the statewide one-meal-per-week consumption advisory. A complete listing of the 2003 advisories on the state’s Fish and Boat Commission's website.

  Source: Pennsylvania Fish Consumption Advisory Updated; No Special Advisories Warranted for State-Stocked Trout. PR Newswire, Feb 24, 2003.

Current Events, News and Journal Articles

• Grocers Post Mercury Warnings on Fish - Several of California's largest grocery chains (e.g., Safeway, Whole Foods, Albertson's, Kroger Company, Bell Market, and Trader Joe's) have started to post signs in their seafood departments warning consumers about the levels of mercury in fresh tuna, shark, and swordfish. The postings are in response to a lawsuit filed in January by the California Attorney General pursuant to the state's strict anti-toxics law (Proposition 65) passed in November 1986. In filing the lawsuit, the state cited results of studies that found high concentrations of mercury in the blood of Bay Area residents who ate large amounts of fish, and that mercury blood levels decreased rapidly when people stopped eating fish. In addition, the state cited sampling results showing that supermarket chains are selling fresh or frozen tuna, shark, and swordfish containing mercury at levels that exceed the state's health standards. The state does not require a warning on canned tuna, but has requested that labeling offer some consumer guidance. The supermarket chains are still negotiating the wording of the final warning. Language suggested by the California Grocer’s Association for posting in stores can be seen on the organization’s website. The grocery chains said they have no plans to post warnings in stores in other states.

  Source: Jay Kay. Grocers post mercury warnings on fish; Safeway and others respond to state suit. The San Francisco Chronicle, February 21, 2003.

• Comparison of Mercury and Methylmercury in Northern Pike and Arctic Grayling from Alaska - In western Alaska, mercury can be a potential health risk to people whose diet is heavily fish-based. In 2000, total Hg (THg) and methylmercury (MeHg) were examined in northern pike (Esox lucius) and Arctic grayling (Thymallus arcticus) from two watersheds in western Alaska, the Yukon and Kuskokwim Rivers. Whitefish (Coregonus sp.) were also examined from the Kuskokwim River. Pike from the Yukon and Kuskokwim Rivers had mean concentrations of THg in muscle of 1.506 and 0.628 ppm (wet wt), respectively. The mean concentrations of THg in grayling muscle from these rivers were 0.264 and 0.078 ppm, respectfully. Whitefish had a mean THg concentration in muscle of 0.032 ppm. In pike and grayling, MeHg constituted nearly 100% of the THg concentrations; the ratio of MeHg/THg was less in whitefish. A significant positive correlation between Hg tissue concentrations and fish body length was also found. Over the last several years, there were no changes in Hg concentrations in pike or grayling. Only pike from the Yukon River had THg concentrations exceeding the USFDA action level for human consumption (1 ppm). To determine the environmental and human health impacts associated with Hg concentrations in western Alaska, further studies are needed to determine potential health risks from increased consumption of resident fishes when anadromous salmon catches are reduced.

  Source: Jewett, S. C., X. Zhang, S.A. Naidu , J.J. Kelley, D Dasher and L.K. Duffy. 2003. Comparison of mercury and methylmercury in northern pike and Arctic grayling from western Alaska rivers. Chemosphere 50 (3):383-392.

• Total Mercury and Methylmercury Content in Mediterranean Fish - The study objectives were to determine current levels of total mercury and methylmercury in muscle tissue of different Mediterranean fish species and whether the levels of mercury exceeded the maximum concentration recommended by the European Commission Decision (ECD). Total mercury levels in muscle tissue of skates ranged from 0.18 to 1.85 ppm (wet weight) (mean, 1.00 ppm), while levels ranged from of 0.11 to 1.92 ppm (wet weight) (mean, 0.70 ppm) for blue whiting, and 0.21 to 1.74 ppm (wet weight) (mean, 0.70 ppm) for red mullet. Total mercury concentrations exceeded the legal limit (1.0 ppm wet weight) for 66.7% of the samples for long nose skates, 61.4% for thornback rays, 42.8% for winter skates, and 38% for starry rays. Mercury concentrations in 63.6% and 40% of blue whiting and striped mullet samples, respectively, exceeded the maximum total mercury level recommended by the ECD (0.5 ppm). Concentrations of methylmercury ranged from 55 to 100% of total mercury in the species tested.

  Source: Storelli, M M., S.R. Giacominelli , A. Storelli, and G.O. Marcotrigiano. 2003. Total mercury and methylmercury content in edible fish from the Mediterranean Sea. J Food Prot 66 (2): 300-303.

• EPA Issues Second Report on Trends in Protecting Children’s Health - EPA Administrator Christie Whitman has announced the release of “America’s Children and the Environment: Measures of Contaminants, Body Burdens, and Illnesses,” the Agency’s second report on trends in environmental factors related to the health and well-being of children in the United States. Drawing on information from various sources, the report shows trends in environmental contaminant levels in air, water, food, and soil; concentrations of contaminants measured in the bodies of children and women; and childhood illnesses which may be influenced by exposure to environmental contaminants. One section of the report discusses exposure to mercury by consumption of contaminated fish.

  Source: www.epa.gov/envirohealth/children

• Factors Influencing the Design of Bioaccumulation Factor and Biota-Sediment Accumulation Factor Field Studies - The author used a series of modeling simulations to evaluate underlying factors that produce uncertainty in measured bioaccumulation factors (BAFs) and biota-sediment accumulation factors (BSAFs) for fish, and to determine sampling designs that minimize the uncertainties. Dominant factors that influenced the field sampling design included temporal variability of chemical concentrations in the water column and the metabolism rate and n-octanol-water partition coefficient (Kow) for the chemical. Of lesser importance were the spatial variability of the chemical concentrations, food chain structure, and the sediment-water concentration quotient. Results of the simulations showed that use of composite water samples in comparison to grab water samples led to reductions in the uncertainties associated with measured BAFs. Some illustrative sampling designs provided a sense of how the number and spacing over time of sampling events might be influenced by differences in temporal variability, metabolism rates, and Kow. Poor spatial coordination of organism, water, or sediment samples can yield BAF and BSAF values with large and unknown biases.

  Source: Burkhard, L.P. 2003. Factors influencing the design of bioaccumulation factor and biota-sediment accumulation factor field studies. Environ Toxicol Chem 22 (2):351-60.

• Concentrations of Metals in Foods and Daily Intake by Children and Adults of Catalonia, Spain - The purpose of this study was to estimate dietary intake of arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) by the general population of Catalonia, Spain. Elemental concentrations were determined in food samples collected randomly in seven Catalonian cities from June to August 2000. Eleven food groups were evaluated. Dietary intake of the trace elements was estimated using a total diet study using recent consumption data on the selected food items. Trace element intake was calculated for five separate population groups: children, adolescents, male and female adults, and senior citizens. The highest dietary intakes of As (223.6 mg/day), Cd (15.7 mg/day), Hg (21.2 mg/day), and Pb (28.4 mg/day) were consumed by male adults. For all four trace elements, fish and shellfish was the food group showing the highest contribution to the dietary intakes. Based on previous studies, a general decrease in As, Cd, Hg, and Pb intake was observed.

  Source: Llobet, J. M., G. Falco, C. Casas, A. Teixido, and J.L. Domingo. 2003. Concentrations of arsenic, cadmium, mercury, and lead in common foods and estimated daily intake by children, adolescents, adults, and seniors of Catalonia, Spain. J Agric Food Chem 51(3): 838-42.

• Determination of PCB Congeners and Pesticides in a Fish Tissue Standard Reference Material - Concentrations of a large number of polychlorinated biphenyl (PCBs) congeners and chlorinated pesticides were determined in a fish tissue Standard Reference Material (SRM) using multiple analytical methods. The reference material, SRM 1946, Lake Superior Fish Tissue, was recently issued by the National Institute of Standards and Technology (NIST) and complements a suite of other marine environmental natural-matrix SRMs that are currently available from NIST for the determination of organic pollutants such as PCBs, polycyclic aromatic hydrocarbons (PAHs), aliphatic hydrocarbons, and organochlorine pesticides. This SRM is a fresh tissue homogenate (frozen) prepared from filleted adult lake trout (Salvelinus namaycush) collected from Lake Superior. SRM 1946 has certified concentrations available for 30 PCB congeners and 15 chlorinated pesticides and reference concentrations available for 12 PCB congeners and 2 chlorinated pesticides. In addition, SRM 1946 is characterized for additional chemical contaminants and properties such as fatty acids, extractable fat, caloric content, total mercury, methylmercury, and selected trace elements. The paper describes the characterization of the chlorinated compounds including the approach used for the certification of PCB congener and chlorinated pesticide concentrations.

  Source: Poster, D.L., J.R. Kucklick, M.M. Schantz, B.J. Porter, S.D. Leigh, and S.A. Wise. 2003. Determination of polychlorinated biphenyl congeners and chlorinated pesticides in a fish tissue standard reference material. Anal Bioanal Chem 375 (2): 223-41.

• Amalgam Restorations and Mercury Levels in Dentists - This study had several objectives; (1) to compare mercury levels in general dentists with levels in other health professionals using toenail clippings as a biomarker, (2) to identify risk factors associated with high mercury concentrations, and (3) to compare dental practices of dentists with both high and low mercury levels. A sample of 579 men was randomly selected from the 33,737 men participating in the Health Professionals Follow-up Study for whom toenail samples were collected in 1987. The subject population was sent a questionnaire in 1991 to obtain information on fish consumption habits, frequency of tooth brushing, number of teeth, number of amalgam restorations, general practice or specialty status, number of amalgam restorations placed and removed per week, mercury storage and handling procedures, and incidents of mercury spillage. The toenail samples provided a long-term assessment of mercury exposure for 410 respondents (71% response rate). The 90th percentile toenail mercury level (0.88 ppm) was selected as the threshold for elevated toenail mercury level. No correlation was found between the number of dental amalgams and toenail mercury concentrations among general dentists, dental specialists, and nondental health professionals. General dentists had more than twice the level of mercury in toenails than nondental health professionals (mean level = 0.94 vs 0.45 ppm) and 60 percent higher than dental specialists (mean = 0.59 ppm). Regardless of their professional status, tuna and saltwater fish consumption were the primary exposure factors that were positively correlated with toenail mercury concentrations.

  Source: Joshi, A., C.W. Douglass, H.D. Kim, K.J Joshipura, M.C. Park, E.B. Rimm, M.J. Carino, R.I. Garcia, J. S. Morris, W. C. Willett. 2003. The relationship between amalgam restorations and mercury levels in male dentists and nondental health professionals. J Public Health Dent 63 (1): 52-60.

• Heavy Metals Near a Chlor-alkali Factory, Argentina - Heavy metal content was determined for sediments and biota of the Upper Negro River, Northern Patagonia, Argentina. The irrigation network of the Neuquen and Negro Rivers parallels these rivers for 150 km, supporting intensive agricultural and economic activities, primarily associated with fruit production. Between 1951 and 1995, a mercury cell chlor-alkali factory operated next to the main irrigation channel, and a drainage channel received plant's effluents between 1951 and 1979. After 1979 until its closure, plant effluents were pumped to a series of evaporation pools. Mercury and other heavy metals (Ag, As, Ba, Co, Cr, Cs, Ni, Sb, Se, U and Zn) were measured in bottom sediments of the river and in the irrigation and drainage channels. Mercury and other metal levels were also measured in two species of aquatic macrophytes, and in liver and muscle tissues of a native fish. No evidence of heavy metal accumulation was shown for river sediments, however, biota indicated that contaminants are entering the rivers. Mercury was the only element accumulated in the main irrigation channel sediments, the highest contents occurring in proximity to the closed chlor-alkali plant, and returning to background value approximately 40 km downstream of the plant. At the plant site, sediments from the channel showed a decrease in Hg content in the upper 10 cm layer, ranging from 0.8 to 3.4 ppm, and from 2.8 to 13.7 ppm in the 10 cm lower layer. Conversely, the drainage channel sediments showed mercury levels of 2-4 ppm, distributed uniformly at various depths and along the channel. Mercury levels in macrophytes downstream of the chlor-alkali plant were higher than the area baseline, and macrophytes and fish liver from the drainage channel exhibited the highest mercury concentration.

  Source: Arribere, M A., G.S. Ribeiro, R.S. Sanchez, M.I. Gil, R.G. Roman, L. E. Daurade, V. Fajon, M. Horvat, R. Alcalde, and A.J. Kestelman. 2003. Heavy metals in the vicinity of a chlor-alkali factory in the Upper Negro River ecosystem, Northern Patagonia, Argentina. Sci Total Environ 301(1-3): 187-203.

• Effect of Lake Nutrient Enrichment on Mercury Concentration in Yellow Perch - The authors evaluated the effect of whole-lake nutrient enrichment on mercury levels in age-1 yellow perch (Perca flavescens). The authors also assessed whether reduced mercury concentrations in fish tissues from enriched lakes were associated solely with enhanced fish growth (i.e., growth dilution). Yellow perch surveyed in eight reference lakes and two experimentally enriched lakes indicated that fish tissue mercury concentration was highly correlated with nutrient enrichment and lake pH. In enriched lakes, age-1 perch were 4 to 5 times larger and had 50% lower mercury tissue levels than perch in reference lakes of equivalent pH (reference lakes=0.24 mug Hg/g wet mass; enriched lakes=0.11 mug Hg/g). Mercury dynamics calculated using a mass balance model indicate that growth dilution can only account for 30-40% of the reduction in yellow perch mercury tissue levels, suggesting that lake enrichment produce effects on fish mercury levels that are not explained by growth rate differences. The remaining difference in yellow perch mercury levels between reference and enriched lakes may be explained by changes in yellow perch diet.

  Source: Essington, T. E. and J.N. Houser. 2003. The effect of whole-lake nutrient enrichment on mercury concentration in age-1 yellow perch. Transactions of the American Fisheries Society 132(1): 57-68.

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For More Information

For more information on EPA's Fish and Wildlife Contamination Program, contact: Jeffrey Bigler at US EPA, 1200 Pennsylvania Ave., NW (4305), Washington, DC 20460; email: bigler.jeff@epa.gov.