Fish and Wildlife Advisory News - July 2003

Recent Advisory News

Current Events, News and Journal Articles

• State hopes to widen hunt for mercury - North Carolina public health officials concerned over human exposure to mercury in fish, water, and air are seeking grants that will enable them to test people who may have been exposed to the contaminant. If the Centers for Disease Control and Prevention approve the grant, thousands of people in North and South Carolina would be tested for mercury . A state toxicologist for North Carolina has estimated that 7,400 children born each year are already at risk from mercury. Each year, the North and South Carolina update fish consumption advisories for their respective states including information on what fish species and waterbodies should be avoided. In 1993, people living along the North Carolina portion of the Waccamaw River were tested to determine the level of mercury in their blood and the study found that people who were frequent fish consumers had blood mercury levels 10 times higher than non fish eaters. Some blood concentrations were among the highest reported in the U.S.

  Source: June 29, 2003. State hopes to widen hunt for mercury. The Associated Press. Appeared in the News and Observer




• Canned tuna is risky for moms-to-be - Mercury levels detected in canned albacore tuna may pose a risk to pregnant women and their babies, according to results of a study conducted by the Mercury Policy Project. Research has linked fetal exposure to mercury from fish to neurological damage that can harm babies' intelligence, coordination or memory. In April, the Centers for Disease Control and Prevention published findings that 8% of women of childbearing age had mercury blood concentrations higher than the dose considered safe by the EPA. The Mercury Policy Project indicated that women that eat just one six-ounce can of white tuna containing 0.5 ppm mercury could potentially receive a dose of mercury two times greater than the level deemed safe by the EPA.

  Source: Shogren, Elizabeth. June 19, 2003. Canned tuna is risky for moms-to-be. Los Angeles Times, pA-20.




• Effects of dietary habits and CYP1A1 polymorphisms on blood dioxin concentrations in Japanese men - In Japan, the major source of dioxin impurities historically was agrochemical formulations; more recently, it has been exhaust from waste incinerators. The authors studied the environmental and genetic factors that influence blood dioxin concentration, and investigated the relationship among dioxin concentrations, dietary habits and cytochorome P450 1A1 (CYP1A1) polymorphisms in Japanese fishermen and farmers, as compared to a group of office workers as controls. The mean dioxin concentrations in the fishermen, the farmers, and the controls were 161,369, 79,079 and 100,500 pg/g fat, respectively. Elevated dioxin concentration with dioxins, furans, and coplanar-PCBs found in the fishermen may be due to the frequent consumption of fish; no such relationship was found either in the farmers or the controls. The authors also found that the levels of congeners found as impurities in certain agricultural chemicals showed no significant differences among the three groups. It is likely that the primary route of dioxin exposure in the Japanese population is through the food chain via fish consumption, regardless of occupation.

  Source: Tsuchiya, Y., S. Nakai, K. Nakamura, K. Hayashi, J. Nakanishi, and M. Yamamoto. 2003. Effects of dietary habits and CYP1A1 polymorphisms on blood dioxin concentrations in Japanese men. Chemosphere 52(1):213-9.




• Fish are central in the diet of Amazonian riparians: should we worry about their mercury concentrations? - The Amazon rain forest harbors a diverse human population distributed in dense cities and isolated communities. Amazonian forest people, either city dweller or frontier riparians living in isolated areas, share the same environment for survival and nutritional status. Feeding strategies depend heavily on cassava products and fish. These two primary foods carry toxic substances such as linamarin (naturally present in cassava) and methylmercury (MeHg) bioconcentrated in fish tissues that cause neurotoxic diseases in other parts of the world, but not in Amazonia. Neurotoxic cases of food origin are rare and not related to these staples. While cassava detoxification processes may partly explain its safe consumption, the MeHg concentrations in Amazonian fish are within safe limits for this population and contribute to an important metabolic interaction with cassava.

  Source: Dorea, J.G. 2003. Fish are central in the diet of Amazonian riparians: should we worry about their mercury concentrations? Environ Res 92(3): 232-44.




• Prenatal methylmercury exposure from ocean fish consumption in the Seychelles child development study - Exposure to methylmercury (MeHg) in utero can adversely affect a child’s neurodevelopment. The most common form of prenatal exposure is maternal fish consumption, but whether such exposure is harmful to the fetus is unknown. The authors research is directed at identifying adverse neurodevelopmental effects in a fish-consuming population. The study investigated 779 mother-infant pairs residing in the Republic of Seychelles. Mothers reported consuming fish on average 12 meals per week. Seychelles fish contain the same concentrations of MeHg as commercial ocean fish elsewhere. Prenatal exposure to MeHg was determined from maternal hair growing during pregnancy. The authors assessed neurocognitive, language, memory, motor, perceptual-motor, and behavioural functions in children at age 9 years. Correlation between prenatal MeHg exposure and the primary neurological endpoints was investigated with multiple linear regression analysis. The authors suggest that these data do not support the hypothesis that there is a neurodevelopmental risk from prenatal MeHg exposure that results solely from ocean fish consumption.

  Source: Myers, G.J., P.W. Davidson, C. Cox, C. F. Shamlaye, D. Palumbo, E. Cernichiari, J. Sloane-Reeves, G.E. Wilding, J. Kost, L. S. Huang, and T.W. Clakson. 2003. Prenatal methylmercury exposure from ocean fish consumption in the Seychelles child development study. Lancet 361(9370): 1686-92.




• Attenuated growth of breast-fed children exposed to increased concentrations of methylmercury and polychlorinated biphenyls - Breast-feeding has been linked to slowed postnatal growth. Although the basis for this link is unclear, environmental pollutants in human breast milk may be of relevance. The authors studied a Faroese birth cohort of 182 singleton children, born at term in 1994-95. Mercury concentrations in cord blood and PCBs levels in maternal milk were measured, and duration of breast-feeding was recorded. At 18 months, children who had been exclusively breast-fed for at least 6 months weighed 0.59 kg less and were 1.50 cm shorter than those not breast-fed. Calculated transfer of pollutants from human milk fully explained the attenuated growth. Irrespective of the duration of breast-feeding, a doubling of the mercury level in cord blood was associated with a decrease in weight at 18 months by 0.19 kg and in height by 0.26 cm. Weight and height at 42 months showed similar trends, but the main effect occurred before 18 months of age. In communities with increased pollutant exposures, risks associated with breast milk transfer of toxicants to the infant must be taken into consideration when judging the risks/benefits of prolonged breast-feeding.

  Source: Grandjean, P., E. Budtz-Jorgensen, U. Steuerwald, B. Heinzow, L.L. Needham, P.J. Jorgensen, and P. Weihe. 2003. Attenuated growth of breast-fed children exposed to increased concentrations of methylmercury and polychlorinated biphenyls. FASEB J. 17(6): 699-701.




• PCDD/Fs and PCBs in Baltic herring during the 1990s - Baltic herring samples collected from the Baltic Sea during spring periods of 1993-1994 and 1999 were analysed for PCDD, PCDF, and PCBs. For these analyses, 1570 individual herring were combined to 120 pools. Correlations between concentrations of congeners 1,2,3,7,8-PeCDD, 1,2,3,7,8-PeCDF, 2,3,4,7,8-PeCDF, and 2,3,4,6,7,8-HxCDF, and age of herring were the strongest (r>0.8) followed by correlations between PCB congeners PCB 105, 118, 126, 156, 169 and 180 r>0.7), and age of herring. Fat content in herring from the Gulf of Bothnia and concentrations of PCDD/Fs and PCBs on fresh weight fw) basis were higher than in herring in the Gulf of Finland. Concentrations of WHO(PCDD/F)-TEQs ranged from 1 to 27 pg/g fw, depending on the age and catchment area of herring, and concentrations of WHO(PCB)-TEQs reached 32 pg/g fw. No clear downward trend in concentrations was observed between the two studied time intervals.

  Source: Kiviranta, H., T. Aartiainen, R. Parmanne, A. Hallikainen, and J. Koistinen. 2003. PCDD/Fs and PCBs in Baltic herring during the 1990s. Chemosphere 50(9): 1201-16.




• Associations between dietary intake and serum polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) levels in Taiwanese - The authors conducted this study to determine the correlation between the consumption frequency of different food groups (milk, eggs, fish, and others) and the levels of serum dioxins and furans (PCDD/F) of residents living near a municipal waste incinerator in Taiwan. All subjects were between 18 and 65 years old and proportionally chosen from each age group based on population distribution. All subjects had lived within a 5-km radius of the incinerator for at least 5 years. Trained interviewers administered a dietary questionnaire. Higher serum PCDD/F levels were found in older rather than in younger subjects, and higher PCDD/F levels were also found in females more than in males. An analysis of consumption frequency of different foods and serum PCDD/F levels revealed that fish have likely contributed the highest quantity of measured serum PCDD/Fs. Frequency of fish consumption appears to be the most significant contributor to serum PCDD/F levels; however, further research is needed to quantify the association.

  Source: Chen, H.L. C.C. Lee, P.C. Liao, Y.L. Guo, C.H. Chen, and H.J. Su. 2003. Associations between dietary intake and serum polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) levels in Taiwanese. Environ Res 91(3):172-8.




• Mercury in fish from three rift valley lakes (Turkana, Naivasha and Baringo), Kenya, East Africa - Mercury concentrations in Kenyan fish from three Rift Valley lakes varied with trophic level, but in general, were not found to pose an unacceptable risk to human consumers or wildlife.

  Source: Campbell, L. M., O. Osano, R.E. Hecky, and D. G. Dixon. 2003. Mercury in fish from three rift valley lakes (Turkana, Naivasha and Baringo), Kenya, East Africa. Environ Pollut 125(2):281-6.




• Distribution of mercury in the aquatic environment at Almaden, Spain - Almaden, Spain is the site of the world's largest mercury mine. There is a lack of information about the environmental impact of these mining activities in the ecosystem surrounding the area. The aim of this study was to document the concentration of mercury in water, sediment, and bivalve mollusks of the aquatic system impacted by historic mine wastes. Samples were collected for the last few years. Mercury levels in water ranged from "not detectable" to 20 ppb. For the sediments study, samples were collected both from contaminated and non-contaminated sites within the basin. The regional background mercury concentration is higher than values typically cited for natural backgrounds. At exposed sites, mercury levels of between 5 and 1000 ppm were measured. These values are one to four orders of magnitude greater than regional background levels. Mercury levels in fresh water bivalves ranged from 1 and 4 ppm(d.w.), with around 30% as methylmercury.

  Source: Berzas Nevado, J.J., L.F. Garcia Bermejo, L. F., and R.C. Rodriguez Martin-Doimeadios. 2003. Distribution of mercury in the aquatic environment at Almaden, Spain. Environ Pollut 122(2):261-71.




• Bioaccumulation of (137)Cs in pelagic food webs in the Norwegian and Barents Seas - Levels of radioactive contamination in fish stocks important to Norwegian fisheries are of major importance to Norwegian consumers and the fish export industry. In this study, the bioaccumulation of caesium-137 has been investigated in marine food webs in the Barents and Norwegian Seas. The levels of (137)Cs in different organisms were generally low (<1 Bq kg(-1) wet weight), but a marked bioaccumulation was apparent. Concentrations of (137)Cs were about 10-fold higher in the harbor porpoise (Phocoena phocoena), representing the upper level of the food web, than in the amphipod (Themisto sp.), representing the lower level of the food web. The BCF increased from 103 for a mixed sample of krill and amphipods to 1655 for harbor porpoises.

  Source: Heldal H.E., Foyn, L., and P. Varskog. 2003. Bioaccumulation of (137)Cs in pelagic food webs in the Norwegian and Barents Seas. J Environ Radioact 65(2):177-85.




• Heavy metals in oysters, mussels and clams collected from coastal sites along the Pearl River Delta, South China - Concentrations of 8 heavy metals: cadmium (Cd), copper (Cu), zinc (Zn), lead (Pb), nickel (Ni), chromium (Cr), antimony (Sb) and tin (Sn) were analyzed in 3 species of bivalves (Perna viridis, Crassostrea rivularis and Ruditapes philippinarum) collected from 25 sites along the Pearl River Delta coastal waters in the South China Sea in 1996. Four metals (Cd, Cu, Zn, and Sn) collected in the three bivalves from the Estuarine Zone were significantly higher than those collected from the Western and Eastern Zones of the Pearl River Delta. These differences are related to the existence of various anthropogenic activities in the catchment of the Pearl River Delta. The Western Zone is mainly impacted by Cr, Ni and Cu contamination. In Victoria Harbor, heavy metal contamination is mainly due to Cu and Pb. Heavy metal levels in the three bivalves were compared with the maximum permissible levels in seafood regulated by the Public Health and Municipal Services Ordinance, Laws of Hong Kong, and it was found that Cd and Cr concentrations in the three bivalves exceeded the upper limits.

  Source: Fang, Z.Q., R. Y. Cheung, and M. H. Wong. 2003. Heavy metals in oysters, mussels and clams collected from coastal sites along the Pearl River Delta, South China. J Environ Sci (China) 15(1):9-24.




• Food safety: Contaminants and Toxins - This book explores recent developments in food safety with regard to toxins and contaminants that may have potential human health impacts. The book is written for students and researchers in food science, nutrition, dietetics, agriculture, and the medical and veterinary sciences. It is divided into 4 major sections including; Biotoxins, Anthropogenic contaminants, Case studies, and Conclusions. Biotoxins include: plant toxins and human health; bacterial pathogens and toxins in foodborne disease; Shellfish toxins; and Mycotoxins in cereal grains, nuts and other plant products. Anthropogenic contaminants includes a discussion of Pesticides; toxicology and residues in food; PCBs; Dioxins in milk, meat, eggs and fish; PAHs in diverse foods; Heavy metals; Dietary nitrates, nitrites and N-nitroso compounds and cancer risk with special emphasis on the epidemiological evidence; and residues and resistant pathogens. The Case studies include: Prion diseases: meat safety and human health implications; safety evaluation of genetically modified foods; genetically modified foods: potential human health effects; Radionuclides in foods: the post-Chernobyl evidence; and Radionuclides in foods: American perspectives. The Conclusions section discusses widespread and continuing concerns over food safety.

  Source: , J.P.F. [Editor]. 2003. Food safety: Contaminants and Toxins. CABI Publishing, CAB International, Wallingford, Oxon OX10 8DE, UK.




• Unsafe fish: The understanding and actions of families and clinicians - {No abstract available}

  Source: K. Moreno and A. Olson. 2003. Unsafe fish: The understanding and actions of families and clinicians. Pediatric-Research. 53 (4 Part 2): 159A.




• Residue depletion of oxytetracycline from fillet tissues of northern pike and walleye - Oxytetracycline (OTC) is a broad-spectrum antibacterial drug used in the U.S. to treat certain diseases in salmonids and catfish. This study was conducted to support an extension of the OTC label to include all cool-water fish species cultured at U.S. aquaculture facilities by satisfying human food safety requirements. Juvenile northern pike were fed OTC-medicated diets near the maximum treatment rate and near the lower limit of the water temperature range for most disease outbreaks in these two species. Two trials were conducted simultaneously with northern pike; one trial used commercially medicated feed and the other used on-site OTC top-coated feed. A third trial was performed with walleye using on-site OTC top-coated feed. Fillet tissues were collected and OTC free base (OTC-base) concentrations were determined. The maximum mean OTC-base concentrations in the fillet tissue were 319 ng/g in northern pike (skinless) and 721 ng/g in walleye (skin-on). These levels were both well below the current tolerance limit of 2000 ng/g OTC-base.

  Source: Bernardy,J. A. C. Vue, M.P. Gaikowski, G.R. Stehly, W.H. Gingerich, and A. Moore. 2003. Residue depletion of oxytetracycline from fillet tissues of northern pike and walleye. Aquaculture 221 (1-4): 657-665.

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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.