Fish and Wildlife Advisory News - February 2003

Recent Advisory News

Current Events, News and Journal Articles

• California Sues Supermarkets for Failure to Warn Public of Mercury in Fish - Lawyers for California filed a lawsuit January 17, 2003 against five supermarket stores, alleging that they failed to properly warn consumers that fresh and frozen fish they sell exposes consumers to mercury. The state’s lawsuit seeks to force these supermarkets to post warnings about mercury in fresh tuna, shark and swordfish (canned tuna was not included). State officials indicated that they were not trying to scare consumers or advise them not to eat fish, but the state wants the FDA federal advice posted at the fish counter so consumers understand there are certain fish species that may be high in mercury. The lawsuit contends that the supermarkets’ failure to provide a warning to consumers violates Proposition 65, a ballot initiative approved in 1986.

  Sources:

  Leslie Earnest. The State of California Sues Supermarkets, Alleging Failure to Warn Public of Health Risks of Mercury in Fish. Los Angeles Times, Jan 18, 2003 pB-10.

  Bob Egelko. State sues 5 grocery giants over toxic in fish - Warning labels sought for mercury levels in packages of swordfish, tuna, shark. San Francisco Chronicle, January 18 2003. Link to the article.

• The Dish on Fish - The January 2003 Harvard Health Letter contains an article discussing the benefits and risks of fish consumption. The article includes an overview of nutritional issues, the debate over farmed vs. wild fish, levels of omega-3 fatty acids, and levels of mercury contamination in different fish based on data from the FDA.

  Source: Harvard Health Letter, January 2, 2003.

• Fish Tissue Quality in the Lower Mississippi River - Between 1990 and 1994, the Louisiana Department of Environmental Quality (LDEQ), in coordination with the US EPA, collected samples of 3 shellfish and 16 fish species at 6 sites along the lower Mississippi River. Organic compound and heavy metal concentrations were measured in 161 composite fish tissue samples where each composite included 3 to 10 individual fish. Nineteen chemicals, found at measurable concentrations in the sample tissues, were used in calculations of cancer and non-cancer risks due to fish consumption. LDEQ calculated: 574 chemical-specific cancer risks; 41 total cancer risks; and 697 margins of exposure based on a fish consumption rate of one 8-ounce meal per week, a body weight of 70 kg, and reported cancer potency factors and reference doses. LDEQ found 9 fish species of concern based on total cancer risk greater than 10(-4) or a margin of exposure greater than 1. These species included the blue catfish, carp, channel catfish, cobia, crayfish, flathead catfish, red drum, spotted gar and striped bass. Chemical contaminants responsible for the elevated cancer risks were aldrin, dieldrin, alpha-benzene hexachloride, gamma-benzene hexachloride, heptachlor epoxide, arsenic, and mercury.

  Source: Watanabe KH, FW Desimone, A Thiyagarajah, WR Hartley and AE Hindrichs. 2003. Fish tissue quality in the lower Mississippi River and health risks from fish consumption. Sci Total Environ. 302(1-3):109-26.

• Neurotoxic Risk Caused by Stable and Variable Exposure to Methylmercury - The objective of this study was to determine whether the dose-effect relationship for developmental mercury neurotoxicity is affected by variable mercury exposure during pregnancy. The study population was a birth cohort of 1,022 children born in the Faroe Islands between March 1986 and December 1987. At age 7, the neurobehavioral performance of 917 children (90%) was evaluated. Intrauterine methylmercury exposure was determined from mercury concentrations in cord blood and 2 sets of maternal hair. The authors found that in children with complete exposure data, 50% of the neuropsychological tests showed deficits significantly associated with the cord-blood mercury concentration. Variable intrauterine exposure was suggested by variability in mercury concentrations in the 2 maternal hair samples. Removing the data results for 61 children (10%) with the greatest degree of variable exposure had a minimal effect on most exposure-effect relationships. However, the effect of the cord-blood mercury concentration on verbal learning and memory was greater after this the exclusion of these data. The authors believe that the study supports previous findings from this cohort study that maternal mercury exposure during pregnancy is associated with neuropsychological deficits detectable at age 7 years and that this association is evident in only in women with stable exposures throughout pregnancy rather than variable exposure.

  Source: Grandjean P, RF White, P Weihe, and PJ Jorgensen. 2003. Neurotoxic risk caused by stable and variable exposure to methylmercury from seafood. Ambul Pediatr 3(1):18-23.

• Assessment of PCB Congener Analytical Methods: Do They Meet Risk Assessment Needs? - Congener-specific PCB analysis permits use of toxic equivalency (TEQ) TCDD-based risk assessment approaches when analytical methods are sufficiently sensitive. Many studies to quantify PCB congeners in fish tissues report the majority of samples as non-detects. These nondetect data are of little use for performing human health risk assessment if the limits of analytical detection exceed concentrations of potential human health concern. Increasing analytical sensitivity is both technically difficult and costly. The authors present an approach to assess analytical sensitivity needs for risk assessments by defining toxicological endpoints of concern and acceptable risk levels. Their framework was used to assess potential PCB TEQ cancer risks to the general population and tribal consumers of Columbia River fish, but is adaptable to other populations. The authors used a probabilistic model to calculate the required analytical sensitivity for PCB TEQ cancer risk assessment using the EPA's new draft cancer risk slope factor for TCDD and fish consumption data. Levels of analytical sensitivity were estimated for the congener (PCB 126) expected to contribute the most to PCB TEQ, and were compared to detection limits for various analytical proceduresThe financial and health value of methods with different levels of analytical sensitivity were compared using a value of information approach. These included analytical cost and cost of potential health outcomes. The authors’ analyses indicated that the average consumption rate, cancer risk slope factor selection, and knowledge of existing PCB contamination are all important factors to consider when planning PCB congener analysis.

  Source: Judd, N L, WC, Griffith, DA Kalman, and EM Faustman. 2003. Assessment of PCB Congener Analytical Methods: Do They Meet Risk Assessment Needs? Arch Environ Contam Toxicol. 44(1):132-9.

• The Relationships Between Heavy Metal Levels and Fish Size - Six heavy metals (cadmium, chromium, copper, iron, lead, and zinc) were measured in the muscle, gill, and liver of six fish species from the northeastern Mediterranean Sea. The relationships between fish size (length and weight) and metal concentrations in the various tissues were investigated by linear regression analysis. Metal tissue concentrations (as mg/g dry weight) generally were highest in the liver and lowest in the muscle of all fish species tested. The highest concentrations of cadmium (4.5 ppm), chromium (17.1 ppm) and lead (41.2 ppm) were measured in liver tissues of T. cuculus, Sardina pilchardus and A. hepsetus, respectively. Liver tissue of M. cephalus exhibited high copper concentrations (202.8 ppm). Gill tissue of Scomberesox saurus was the only tissue that showed the highest iron concentration (885.5 ppm). The analysis showed that with few exceptions, significant relationships (P<0.001) between metal concentrations and fish size were negatively correlated.

  Source: Canli, M. and G Atli. 2003. The relationships between heavy metal (Cd, Cr, Cu, Fe, Pb, Zn) levels and the size of six Mediterranean fish species. Environmental Pollution 121(1):129-36.

• Mercury Levels in Some New Zealand Marine Fish - Two groups of fish tissue samples (spanning 16 years) were analyzed for methylmercury and total mercury content. All samples were collected from commercial catches and represent 33 different commercially important New Zealand marine fish species. Results of the analysis show that the New Zealand fish species sampled have mean total mercury concentrations ranging between 0.02 and 2.48 ppm and mean methylmercury concentrations ranging from less than 0.04 to 1.97 ppm.

  Source: Love JL, GM Rush, and H McGrath. 2003. Total mercury and methylmercury levels in some New Zealand commercial marine fish species. Food Addit Contam 2003. 20(1):37-43.

• DDT and HCH Residues in Fish from the the Taihu Lake Region, China - The use of the organochlorine pesticides DDT and hexachlorocyclohexane (HCH) has been banned in China for more than two decades. A field survey was conducted from 1999-2000 in the Taihu Lake Region of China. Pesticide residues were analyzed in soil, water, fish, and sediment samples. DDT was detected in 50% of soil samples at concentrations ranging from 0.3 to 5.3 ppb in the surface (0-15 cm) layer, 60% of samples ranging from 0.5 to 4.0 ppb in the subsoil layer (16-30 cm), and in 40% of samples ranging from 0 to 2.7 ppb in the deep soil layer (31-50 cm). Similar results were obtained for HCH. These findings suggest DDT and HCH residues in the 0-50 cm profile had been leached or degraded to safe levels. DDT was detected in 77% of river water samples at concentrations ranging from 0.2 to 9.3 ppb, with an average of 1.0 ppb. HCH was detected in 92% of samples at concentrations ranging from 0.02 to 36.1 ppb, with an average 5.6 ppb. DDT sediment residues ranged from 0.1 to 8.8 ppb, while HCH residues ranged from 0.3 to 66.5 ppb. DDT and HCH residues in fish tissue ranged from 3.7 to 23.5 ppb and 3.7 to 132 ppb, respectively. Study results show accumulation of these contaminants through food chain, and that HCH residues are generally more persistent than DDT residues.

  Source: Feng K, Y B Yu, DM Ge, MH Wong, XC Wang, and ZH Cao. 2003. Organo-chlorine pesticide (DDT and HCH) residues in the Taihu Lake Region and its movement in soil-water system I. Field survey of DDT and HCH residues in ecosystem of the region. Chemosphere 50 (6):683-687

• Horizontal and Vertical Distribution of Organic Contaminants in Deep Sea Fish - The authors investigated the distribution of selected PCBs and pesticides with depth and longitude in various deep-sea fish from the waters off Madeira, Sesimbra, and the Meriadzec, Terrace, and Rockall Trough in the North Eastern Atlantic at depths of 1000 and 2000 meters. Generally, male finfish exhibited higher levels of contamination than females of the same species. This pattern may have resulted from the females eliminating contaminants through egg production. Roundnose grenadier exhibited higher p,p'-DDE, PCB 153, 138, 180, and p,p'-DDT concentrations in fish caught at 2000 m than at the shallower 1000 m depth. Some species showed much higher concentrations of PCBs and pesticides than other species.

  Source: Mormede S and I M Davies. 2003. Horizontal and vertical distribution of organic contaminants in deep-sea fish species. Chemosphere 50 (4): 563-574.

• Concentrations and Hazard Assessment of Contaminants in Fish Species from the Upper Thames - Contamination levels of organochlorine pesticides, PCBs, and heavy metals in the Upper Thames catchment area, UK were analyzed in fish muscle analysis (ppb, wet weight), and their effects on top fishing predators were evaluated. Contaminant levels of lead, cadmium, DDT and its metabolites were found to be low (undetectable) in the area. However, mean mercury concentrations varied between 55 and 342 ppb, dieldrin ranged from < 0.09 to 36.8 ppb, lindane ranged from <0.08 to 4.94 ppb, and PCBs ranged from <0.77 to 3.32 ppb. Eels exhibited much higher concentrations of OCPs than other fishes from the same monitoring stations. PCB contamination levels were likely associated with industrial and human activities, but no such associations for mercury were found. The hazard indices (HI) of both dieldrin and PCBs were below 1 for mink. However, the HI of mercury in all fish species from all monitoring sites were above 1 for mink. Mercury levels may be less harmful to polecats, but more harmful to otters as their diets are dominated by aquatic fish.

  Source: Yamaguchi, N., D Gazzard, G Scholey, and DW Macdonald. 2003. Concentrations and hazard assessment of PCBs, organochlorine pesticides and mercury in fish species from the upper Thames: River pollution and its potential effects on top predators CHEMOSPHERE 50 (3): 265-273.

• Tributyltin Causes Masculinization in Fish - The effect of tributyltin (TBT) on the sex differentiation process in genetically female Japanese flounder were examined. Fish were fed artificial diet containing tributyltin oxide (TBTO) at concentrations of 0.1 and 1.0 mg/g diet from Day 35 to 100 post-hatching, which includes the sex differentiation period. The ratio of sex-reversed males significantly increased to 26% of the flounder fed the 0.1 ppm diet and to 31% of those fed the 1.0 ppm diet compared with 2% in the control. This study is the first reported of TBT - induced sex reversal in vertebrates.

  Source: Shimasaki Y, T Kitano , Y Oshima, S Inoue, N Imada, and T Honjo. 2003. Tributyltin causes masculinization in fish. Environ Toxicol Chem. 22(1):141-4.

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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.