Fish and Wildlife Advisory News - October 2002

Recent Advisory News

• Brominated flame retardants in Arctic animals - A story reported by the BBC states that brominated flame retardants (BFRs) are being found in polar bears, seabird eggs, and other animals from the Norwegian Arctic. People in these areas are being warned not to eat the seabird eggs because of the high concentrations of BFRs. Geir Wing Gabrielsen, who has been conducting research in this area for 20 years, said that levels of BFRs are three times higher in Canadian seals than they were 10 years ago. Also, he has noticed that the polar bear cub survival rate In the Norwegian Arctic is much lower than in the North American Arctic areas. Gabrielson has extended his research this year from colonies in northern Norway to Svalbard, Russia's Kola peninsula, and the Faeroe islands. He said he has found high levels of PCBs, dioxins and BFRs in seabird eggs. Says Gabrielson, "Some people in mainland Norway are very fond of the eggs. But eating a single one can increase your body burden of these organic pollutants by 10%. We're advising children and women of child-bearing age not to eat any." Although the health effects of BFRs have not been extensively studied, a source told the BBC “They've been shown to affect behaviour in laboratory animals, particularly brain development, and that sort of effect on learning seems to get worse as the animal ages.”

  Source: Kirby, A. 2002. Chemicals spark Arctic alert. BBC News Online 26 September 2002. news.bbc.co.uk

• Mercury, other toxins threaten peoples, wildlife of the Arctic, report says - A report on Arctic pollution was released in early October by the Norway-based Arctic Monitoring and Assessment Program (AMAP), reported the Associated Press (AP). The report, entitled Arctic Pollution 2002, says that mercury and other toxins in the food chain are threatening humans and wildlife in the Northern Hemisphere, leading to high blood pressure in newborn babies and causing polar bears to lose cubs at birth. Lars-Otto Reiersen, one of the compilers of the report, told the AP "We were really surprised by the mercury problem. The amount of mercury transported into the area seems to be much higher than anyone believed before." Indigenous peoples, especially the Inuit in Greenland and Canada, are particularly vulnerable because they depend on whale blubber and seal meat containing high concentrations of toxins. The effects of the toxins are also felt in the Faeroe Islands, according to the AMAP report. Reiersen also said polar bears are giving birth to fewer cubs, and many more are dying at birth because of the toxins. The AP reports that in a separate study, female polar bears with both male and female sexual organs were discovered in 1997 on Norway's Svalbard Archipelago. Researchers believe the deformity could be due to PCBs and other toxins.

  Source: Huuhtanen, Matti. 2002. Mercury, other toxins threaten peoples, wildlife of the Arctic, report says. October 02, 2002, The Associated Press. Reported on the Environmental News Network

  The AMAP report is available online via the World Wildlife Fund website

Current Events, News and Journal Articles

• Mercury concentrations in fish from Lake Mead - For this study, total mercury concentrations were determined in the muscle fish collected from Lake Mead, and the results were analyzed with respect to fish size, condition, trophic level, and location. Mercury concentration generally increased with trophic level and fish size. Median Hg concentrations (ng/g wet mass) were 277 in striped bass, 168 in channel catfish, 160 in largemouth bass, 75 in bluegill, and 8 in blue tilapia. Researchers also found that concentrations of mercury in striped bass were inversely correlated with a fish nutritional-status factor. This is consistent with starvation-concentration, whereby mercury in fish muscle is lost at a slower rate than the muscle mass. For striped bass, based on the results the researchers recommend a risk-based consumption limit of three 8-oz. meals per month for a 70-kg adult.

  Source: Cizdziel, J V, Hinners, T A, Pollard, J E, Heithmar, E M, Cross, C L. 2002. Mercury concentrations in fish from lake mead, USA, related to fish size, condition, trophic level, location, and consumption risk. Arch Environ Contam Toxicol 2002 Oct; 43(3):309-17.

• Atmospheric transport of toxaphene to the Great Lakes - The authors set out to study the atmospheric transport of toxaphene from the southern United States (where it was historically used as an insecticide on cotton fields) by implemented a sampling network to measure the gas-phase concentrations of toxaphene near Lake Michigan, MI; Bloomington, IN; Lubbock, TX; and Rohwer, AR. The toxaphene concentration data were combined with a nonparametric, backward trajectory, multiple regression model. The model results indicated that the sources of toxaphene are located south of the sampling sites. The authors also compared the chemical behavior of toxaphene in the atmosphere and found that the congener ratios were similar at the different sampling sites but slightly different from various toxaphene standards.

  Source: James RR, Hites RA. 2002. Atmospheric transport of toxaphene from the southern United States to the Great Lakes Region. Environ Sci Technol 15; 36(16):3474-81.

• A dynamic mass budget for toxaphene in North America - The authors present a continental-scale dynamic mass budget for toxaphene in North America, based on available information on physicochemical properties, usage patterns, and reported environmental concentrations. The Berkeley-Trent North American mass balance contaminant fate model (BETR North America) was used to describe contaminant fate in 24 ecological regions of North America, including advective transport between regions in the atmosphere, freshwater, and near-shore coastal water. The dynamic mass budget accounts for environmental partitioning, transport, and degradation of the estimated 534 million kg of toxaphene that were used in North America as an insecticide and piscicide between 1945 and 2000. Based on the results, an estimated 15 million kg of toxaphene are believed to remain in active circulation in the North American environment in the year 2000, with the majority in soils in the southern United States and Mexico, where historic usage was highest. Approximately 70% of total toxaphene deposition from the atmosphere to the Great Lakes is attributed to sources outside the Great Lakes Basin, and an estimated total of 3.9 million kg of toxaphene have been transported to this region from other parts of the continent.

  Source: MacLeod M, Woodfine D, Brimacombe J, Toose L, Mackay D. 2002. A dynamic mass budget for toxaphene in North America. Environ Toxicol Chem 21(8):1628-37.

• Dietary fish oil and risk of colon cancer in rats - The authors examined the effect of different dietary fiber and fat sources on an azoxymethane (AOM)-induced colon cancer in rats. Abnormalities in colon tissues (quantified as aberrant crypt foci, or ACF) were studied among rats fed on different diets. ACF counts were higher in rats fed sunflower seed oil and resistant starch than those fed fish oil and alpha-cellulose. Rats fed fish oil had 19% fewer ACFs than those fed sunflower seed oil. These results show that the greatest protection from ACFs was associated with alpha-cellulose as the fiber source and fish oil as the fat source.

  Source: Coleman LJ, Landstrom EK, Royle PJ, Bird AR. McIntosh GH. 2002. A diet containing alpha-cellulose and fish oil reduces aberrant crypt foci formation and modulates other possible markers for colon cancer risk in azoxymethane-treated rats. J Nutr 132(8):2312-8.

• Contaminants in fish from the Mississippi River basin - Common carp and black bass collected in 1995 from 34 National Contaminant Biomonitoring Program (NCBP) stations and 13 National Water Quality Assessment Program (NAWQA) stations in the Mississippi River basin, and from a reference site in West Virginia, were analyzed for organochlorine chemicals. At the NCBP stations, which are located on relatively large rivers, concentrations of organochlorine chemical residues were generally lower than when last sampled in the mid-1980s. DDE was detected at all sites, including the reference, although only traces of DDT were present, which indicates continued weathering of residual DDT from past use. Nevertheless, researchers found that concentrations of DDE in fish from the Mississippi River basin were great enough to constitute a hazard to fish-eating wildlife and were especially high at the NAWQA sites on the lower-order rivers and streams of the Mississippi embayment. Mirex was detected at only two sites, both in Louisiana, and toxaphene was found exclusively in the lower Mississippi River basin. Most cyclodiene pesticides (dieldrin, chlordane, and heptachlor generally lower than in the 1980s. PCB concentrations generally declined, and residues were detected at only 35% of the stations, mostly in the more industrialized parts of the Mississippi River basin.

  Source: Schmitt, C J. 2002. Organochlorine chemical residues in fish from the Mississippi River basin, 1995. Arch Environ Contam Toxicol 43(1):81-97.

• Bioaccumulation within the sanddab guild, southern California - This study tests the hypothesis that the use of ecologically similar species (a guild) might provide better assessments of fish contamination across different sites and depths in the coastal waters of southern California. To test this, samples of four sanddab guild species were analyzed for total DDT concentrations. Log-transformed DDT concentrations were highly correlated among all species pairs within this guild. The variability in response among species was about four times the variability encountered among replicates within species, but 15 times smaller than the variability among sites. Based on these results, the authors suggest that the sanddab guild can be used as a "superspecies" in bathymetrically diverse regional assessments of fish tissue contamination.

  Source: Allen, M J, Moore, S L, Weisberg, S B, Groce, A K., Leecaster, M K. 2002. Mar Pollut Bull 44(6):452-8. Comparability of bioaccumulation within the sanddab guild in coastal Southern California.

• Modeling the radionuclide dose from consumption of Hong Kong fish - This paper discusses the results of a compartmental model for estimating the ingestion dose of 137Cs (a radionuclide released in routine liquid effluents from a nearby nuclear power station) from the consumption of marine fish in Hong Kong. Assuming the discharge of this radionuclide is maintained at a constant rate, the model shows that the predicted annual dose to an average local individual in Hong Kong is low, and it is dominated by the contribution from fish cultured in Hong Kong waters. The annual dose to members of the critical group of local fish farmers does not exceed 3.0 x 10(-3) microSv. All of the estimated doses are small compared to the dose received from naturally occurring radionuclides found in marine fish. The authors also discuss difficulties encountered in model validation.

  Source: Poon, C B, Au, S M. 2002. Modeling the 137Cs ingestion dose from consumption of marine fish in Hong Kong. Radiat Prot Dosimetry 98(2):199-209.

• Fast, simple total mercury determination method for fish tissue - This study evaluated a fast, simple procedure for measuring total mercury in fish tissues. Wet weight fish tissues were analyzed directly for mercury (without acid digestion) using an automated instrument incorporating combustion, preconcentration by amalgamation with gold, and atomic absorption spectrometry (AAS). Seven tissue types (skeletal muscle, liver, blood, gonad, brain, gill, and heart) from five species (340 fish) were analyzed. Comparisons to conventional cold-vapor AAS (CV-AAS) and isotope dilution inductively coupled plasma mass spectrometry found that the methods give statistically equivalent results. Because the combustion-AAS method is faster than conventional CV-AAS and produces no waste reagents, the authors suggest that it should be particularly useful for laboratories that analyze large numbers of fish for mercury. The method detection limit for fish-muscle homogenate was estimated at 0.9 ng/g super.

  Source: Cizdziel, JV; Hinners, TA; Heithmar, EM. 2002. Determination of Total Mercury in Fish Tissues using Combustion Atomic Absorption Spectrometry with Gold Amalgamation. Water, Air, & Soil Pollution Vol. 135, no. 1-4, pp. 355-370.

• Mercury in fish and other foods in Saudi Arabia - Locally-bred fish samples were collected from the Kingdom of Saudi Arabia (KSA) and analyzed for the presence of Cd, Pb and Hg using atomic absorption spectrometry. The levels of Pb and Cd were lower than the reported values while the level of Hg in most samples was higher than the reported values. The daily intake of Cd, Pb and Hg was calculated by using the FAO food balance sheet of Saudi Arabia and questionnaires distributed to 200 families in Jeddah. This information, combined with the metal concentration values in fish, showed that the daily intake of Cd and Pb was much lower than the permissible value given by World Health Organization. However, the daily intake of Hg was higher than the permissible value according to the FAO source.

  Source: Mofida, W. A. E. 2002. Determination of some toxic elements in local foodstuff of Saudi Arabia Kingdom using atomic absorption spectroscopy. Journal of the Saudi Chemical Society 6(1):p.7-13

• Mercury in tuna from the Mediterranean - This study examined the current levels of total mercury and methylmercury in albacore and bluefin tuna caught in the Mediterranean. Total mercury concentrations ranged from 0.84 to 1.45 ppm wet weight (mean 1.17 ppm) and from 0.16 to 2.59 ppm (mean 1.18 ppm) in the muscle of albacore and bluefin tuna, respectively. In 78.6% of albacore and in 61.1% of bluefin tuna, total mercury concentrations exceeded the maximum level fixed by the European Commission Decision (1 ppm wet wt). The estimated weekly intake was far above the established Provisional Tolerable Weekly Intake for both species.

  Source: Storelli, M M, Stuffler, R G, Marcotrigiano, G O. 2002. Total and methylmercury residues in tuna-fish from the Mediterranean sea. Food Addit Contam 19(8):715-20.

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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.