Fish and Wildlife Advisory News - October 2003

Current Events, News and Journal Articles

• Spawning salmon deliver pollutants- A new study reported some of Alaska's pristine and remote lakes are becoming polluted with industrial PCBs through migrating fish: sockeye salmon. Salmon accumulate the PCBs in the northern Pacific Ocean and then return to the lakes to spawn. When the salmon die, their bodies release the pollutant, thereby increasing PCB levels in the lake sediment more than sevenfold in some lakes. This research is reported in the September issue of the journal Nature.

  The researchers do not know whether the pollution is affecting the wildlife in the lakes by weakening their resistance to disease or causing other effects. The lakes studied are too far from human populations to pose any health hazards to people, and the PCB levels in the lake sediments are too low to justify cleanup projects. The salmon themselves do not contain enough PCBs to be hazardous if eaten. The study shows what can happen if enormous numbers of the fish concentrate in small lakes that are not representative of all Alaskan lakes or rivers. PCBs concentrate in food chains, and killer whales off British Columbia have accumulated high levels, apparently by eating contaminated salmon and seals. The study included eight lakes on Kodiak Island and the nearby Alaskan mainland that have a wide range of densities of spawning salmon. The samples of lake sediments were collected during 1995, 1997, 1998 and 2002. In general, the authors found that the higher the concentration of spawning salmon in a lake, the higher the PCB concentration in its sediment. That suggests the salmon were responsible for the variation in PCB levels.

  Source: Ritter, M. 2003. Spawning salmon deliver pollutants. Associated Press. Posted on Wednesday, September 17, 2003.




• Eating tropical fruit reduces mercury exposure from fish consumption in the Brazilian Amazon- The authors examined the influence of consumption of traditional foods on the relationship between fish consumption and mercury (Hg) exposure. A 12-month prospective dietary survey was conducted with 26 adult women from a fish-eating community in the Brazilian Amazon. Food consumption was determined using a daily food diary, and total hair Hg levels were assessed for each month through sequential analyses. Simple and multiple regression analyses revealed there was a strong relationship between fish consumption and mercury exposure, and that mercury exposure was significantly modified by fruit consumption. Of the women who ate the same number of fish meals, those who ate more tropical fruits in their diet had lower mercury hair levels than those who ate less fruit. The findings indicate there may be different ways of maintaining fish consumption while reducing Hg exposure in the Amazon. Several phytochemicals and nutritional fibers present in tropical fruits might be interacting with the Hg in several ways, including via absorption and excretion, transport, binding to target proteins, metabolism, and sequestration. Addition studies are needed on larger populations to further elucidate the extent and public health implications of the use of fruits to counteract the toxic effects of methylmercury.

  Source: Passos, C., D. Mergler, E. Gaspar, S. Morais, M. Lucotte, F. Larribe, R. Davidson, and S. Grosbois. 2003. Eating tropical fruit reduces mercury exposure from fish consumption in the Brazilian Amazon. Environmental Research, 93 (2): 123-30.




• A review and comparison of models for predicting dynamic chemical bioconcentration in fish - Over the last 20 years, a variety of models have been developed to simulate the bioconcentration of hydrophobic organic chemicals by fish. These models differ not only in the processes addressed, but in the way a given process is described. The processes described by these models include: chemical diffusion through the gill's interlamellar water, epithelium, and lamellar blood plasma; advective chemical transport to and from the gill by ventilation and perfusion, and internal chemical deposition by thermodynamic partitioning to lipids and other organic phases. The author reviews the construction and associated assumptions of 10 of the most widely cited fish bioconcentration models. Models are compared with respect to their ability to predict observed uptake and elimination rates using a common database for those model parameters that they have in common. Statistical analyses of observed and predicted exchange rates show that rates predicted by these models can be calibrated almost equally well to actual data. The importance of gill exchange models and how to improve them are also discussed.

  Source: Barber, M. 2003. A review and comparison of models for predicting dynamic chemical bioconcentration in fish. Environmental Toxicolology and Chemistry 22 (9): 1963-92.




• Temporal changes in mercury bioaccumulation by predatory fishes of boreal lakes following the invasion of an exotic forage fish - The authors evaluated the prediction that mercury concentrations in predatory fishes in boreal lakes would increase following the invasion of an exotic forage fish (rainbow smelt, Osmerus mordax) that was believed to feed at a higher trophic position than native forage fishes. Comparison of temporal trends (postinvasion minus preinvasion values) in fish mercury bioaccumulation were studied between lakes experiencing recent smelt invasions and reference lakes of central Canada. Piscivore mercury levels in this region have remained stable or decreased during the last 20 years. These trends were not strongly influenced by the smelt invasion, despite the fact that smelt are a major prey species for all piscivore species examined. The effect of the smelt invasion on bioaccumulation of mercury in the predator species reflected the importance of smelt in their respective diets (lake trout, walleye, northern pike). The observed effects, however, were not statistically significant for any piscivore species. Effects of rainbow smelt invasion on mercury bioaccumulation in native piscivores have been much smaller than previous food-web studies in this region have predicted.

  Source: Johnston, T., W. Leggett, R. Bodaly, and H. Swanson. 2003. Temporal changes in mercury bioaccumulation by predatory fishes of boreal lakes following the invasion of an exotic forage fish. Environmental Toxicology and Chemistry 22 (9): 2057-62.




• Mercury in UK imported fish and shellfish and UK-farmed fish and their products - The authors measured the total mercury levels in fish and shellfish and their products imported into the UK and also in UK-farmed salmon and trout. The authors collected 336 samples and sampling was weighted to reflect consumption, but with some bias towards fish that might accumulate higher levels of mercury (large predatory fish). The highest concentrations of total mercury were measured in billfish (swordfish and marlin) and shark. Mercury levels in the 5 samples of fresh/frozen shark ranged from 1.006 to 2.200 ppm, and all samples were above the European Commission limit for mercury. Mercury concentrations in 20 samples of fresh/frozen billfish ranged from 0.153 to 2.706 ppm and 13 samples exceeded the 1.0 ppm limit. One sample of fresh/frozen tuna out of the 20 collected had a mercury concentration above the limit of 1.0 ppm, but all other fresh tuna samples were below the regulatory limit. Mercury levels in canned tuna were lower, with concentrations on average half that measured in fresh/frozen tuna. Mercury concentrations in UK-farmed salmon and trout were relatively low. In 46 samples of fresh/frozen or smoked trout and salmon, the maximum concentration detected was 0.103 ppm.

  Source: Knowles, T., D. Farrington, and S. Kestin. 2003. Mercury in UK imported fish and shellfish and UK-farmed fish and their products. Food Additives and Contamination 20 (9): 813-8.




• Developing risk-based target concentrations for carcinogenic polycyclic aromatic hydrocarbons (PAHs) assuming human consumption of aquatic biota - Target groundwater concentrations were developed as goals for the planned cleanup efforts as part of a remediation process at a former creosote facility in Washington State. State regulatory requirements and site-specific conditions determined the concentrations established to protect surface water in the lake adjacent to the site. These risk-based values were calculated assuming that the chemical will (1) leach into groundwater, (2) be discharged into the lake, and (3) be bioaccumulated by aquatic organisms that may be consumed by humans. Among the primary chemicals driving remediation decisions at this site are carcinogenic PAHs, which have limited environmental mobility and are metabolized by many edible fish. The authors assessed the validity for PAHs of the required default regulatory assumptions and derived alternative risk-based concentrations. Their analyses focused on factors that would modify the generic assumption regarding bioconcentration of PAHs in aquatic biota and influence bioavailability of PAHs to humans consuming fish or shellfish. Modifications based on these factors and the use of toxicity equivalency factors resulted in alternative risk-based concentrations for individual PAHs that ranged from approximately 7 to 700 times higher than the default value of 0.03 ppb.

  Source: Petito, B., and M. Garry. 2003. Developing risk-based target concentrations for carcinogenic polycyclic aromatic hydrocarbons (PAHs) assuming human consumption of aquatic biota. J Toxicol Environ Health B Crit Rev 6 (5): 497-520.




• The chemical form of mercury in fish - The primary dietary source of mercury in the human diet is via ingestion of methylmercury accumulated in fish. Despite its importance, a complete understanding of the chemical identity of mercury in animal tissue remains unknown. Toxicity properties of any metal are dependant on molecular form; for example, dialkylmercury derivatives are toxic at such low concentrations that they are considered supertoxic, whereas mercuric selenide has a relatively low toxicity and accumulates in marine mammals as an apparently benign detoxification product. Mercury is very flexible in its coordination of nonmetallic elements, with structurally characterized species exhibiting coordination numbers between two and eight. Although not often applied to molecular toxicology, X-ray absorption spectroscopy (XAS) is ideally suited to identification of chemical forms in situ.

  Source: Harris, H., I. Pickering, and G. George. 2003. The chemical form of mercury in fish. Science 301 (5637): 1203.




• Sub-clinical neurobehavioral abnormalities associated with low levels of mercury exposure through fish consumption - The authors assess early neurotoxic effects associated with relatively low levels of mercury absorbed through fish consumption by two groups of 22 adult male subjects. One group included habitual consumers of tuna fish, and the other 22 were controls. Both groups were examined using a cross-sectional field study. The study assessed neurobehavioral tests of vigilance and psychomotor function, hand tremor measurements, and serum prolactin. Mercury in urine (U-Hg) and serum prolactin (sPRL) were measured in all exposed subjects and controls, while measurements of the organic component of mercury in blood (O-Hg) were available for only 10 exposed and 6 controls. U-Hg was significantly higher among exposed subjects (median 6.5 microg/g of creatinine) than controls (median 1.5 microg/g of creatinine). The median values of O-Hg were 41.5 microg/l among the tuna fish eaters and 2.6 microg/l in the controls. Both forms of mercury, U-Hg and O-Hg were significantly correlated with the amount of fish consumption per week. Neurobehavioral performance of subjects who consumed tuna fish regularly was significantly worse on color word reaction time, digit symbol reaction time, and finger tapping speed than on the controls. After considering the education level and other covariates, the multiple stepwise regression analysis indicated that O-Hg level was most significantly associated with individual performance on these tests, accounting for about 65% test score variance.

  Source: Carta, P., C. Flore, R. Alinovi, A. Ibba, M. Tocco, G. Aru, R. Carta, E. Girei, A. Mutti, R. Lucchini, F. Randaccio. 2003. Sub-clinical neurobehavioral abnormalities associated with low level of mercury exposure through fish consumption. Neurotoxicology 24 (4-5): 617-23.




• Polychlorinated biphenyls and organochlorine pesticides in edible fish species and dolphins from Guanabara Bay, Rio de Janeiro, Brazil - {No abstract available.}

  Source: da Silva, A., V. Lemes, H. Barretto, E. Oliveira, I. de Alleluia, and F. Paumgartten. 2003. Polychlorinated biphenyls and organochlorine pesticides in edible fish species and dolphins from Guanabara Bay, Rio de Janeiro, Brazil. Bull Environmental Contamination and Toxicololgy 2003 70 (6): 1151-7.




• Biomagnification factors (fish to osprey eggs from Willamette River, Oregon, U.S.A.) for PCDDs, PCDFs, PCBs and OC pesticides - In 1993, a migratory population of 78 pairs of osprey (Pandion haliaetus) nesting along the Willamette River in Oregon was studied. The goal was to determine contaminant concentrations in osprey eggs, in fish species predominant in the ospreys' diet, and Biomagnification Factors (BMFs) of contaminants from fish species to osprey eggs. Ten eggs and 25 composite samples of 3 species of fish were sampled to determine organochlorine pesticides, polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs). Mercury was also analyzed in fish. Geometric mean residues in osprey eggs were low (e.g., DDE 2.3 ppm wet weight, PCBs 0.69 ppm, 2,3,7,8-TCDD 2.3 pptr) and generally well below known threshold values for adverse effects on productivity. In addition, the osprey population is increasing. Osprey egg residue data revealed that higher PCDDs were generally found immediately downstream of paper mills and eggs from the Willamette River had significantly elevated PCBs and PCDDs compared to reference group eggs collected from the Cascade Mountains. At the nesting sites, prey remains indicated that the Largescale Sucker (Catostomus macrocheilus) and Northern Pikeminnow (Ptychocheilus oregonensis) accounted for 90.1% of the biomass in the bird’s diet. Composite samples of these fish species were collected from different sampling sites throughout the study area for contaminant analyses. The authors estimated a mean BMF from fish to osprey eggs for a large series of contaminants. BMFs ranged from no biomagnification (0.42) for 2,3,7,8-TCDF to 174 for OCDD. The authors' findings for the migratory osprey were compared to BMFs for the resident herring gull (Larus argentatus), and differences are discussed. The BMF approach provides some basic understanding of relationships between pollutant burdens in prey species of fish-eating birds and pollutants incorporated into their eggs, and this may prove useful in understanding sources of contaminants in migratory species.

  Source: Henny, C., J. Kaiser, R. Grove, V. Bentley, and J. Elliott. 2003. Biomagnification factors (fish to osprey eggs from Willamette River, Oregon, U.S.A.) for PCDDs, PCDFs, PCBs and OC pesticides. Environmental Monitoring and Assessment 84 (3): 75-315.




• Determination of cadmium, chromium, lead, and vanadium in six fish species from the Adriatic Sea - Cadmium, chromium, lead, and vanadium concentrations were determined in samples of 6 fish species collected along the Adriatic coast. The metal concentrations studied were generally low, often below the detection limits of the analytical methods. The highest values (ppb) fresh weight were observed, primarily, in the central area of the Adriatic Sea, for anchovy (Cd 20.2 ppb, Cr 82.9 ppb, Pb 45.9 ppb, V 89.9 ppb), red mullet (Cd 3.1 ppb, Cr 31.0 ppb, Pb 36.0 ppb, V 79.1 ppb) and mackerel (Cd 7.7 ppb, Cr 28.0 ppb, Pb 11.4 ppb, V 43.5 ppb). Cadmium and lead concentrations in all species examined were below the maximum levels indicated by the European Community for these two metals in seafood, and also would lead to exposure levels lower than the provisional tolerable daily intakes suggested by the FAO/WHO for cadmium (420 micrograms per week for a 60-kg person) and lead (1500 micrograms per week for a 60-kg person). Chromium levels were lower than the recommended daily limit (50-200 micrograms per day for a 60-kg person) indicated by the US National Research Council. For the population of the Adriatic coast, an 11-34% contribution to the daily vanadium ingestion with fish was calculated.

  Source: Sepe, A., L. Ciaralli, M. Ciprotti, R. Giordano, E. Funari, and S. Costantini. 2003. Determination of cadmium, chromium, lead and vanadium in six fish species from the Adriatic Sea. Food Additives and Contamination 20 (6): 543-52.




• Consumption of fish from polluted waters by WIC participants in East Harlem - The New York State Department of Health issues health advisories about consumption of certain fish and shellfish caught from polluted local waters to minimize exposure to neurotoxins such as mercury, polychlorinated biphenyls (PCBs), dioxins, and pesticide residues in fish. Fetal exposure results in cognitive developmental deficits in children exposed to these chemicals. Fish consumption was assessed in 220 WIC (Special Supplemental Nutrition Program for Women, Infants, and Children) participants. Of the surveyed participants, 10% ate fish and shellfish caught in local waters. Statistically significant factors associated with eating local, noncommercial fish included male gender and knowledge of the health advisory. Locally caught fish and crabs are consumed; thus, in utero and childhood exposure to these neurotoxins occurs. Interventions are needed to promote safer choices of fish.

  Source: Bienenfeld, L., A. Golden, and F. Garland. 2003. Consumption of fish from polluted waters by WIC participants in East Harlem. Journal of Urban Health 80 (2): 349-58.




• Estimation of daily mercury intake from seafood in Japanese women: Akita cross-sectional study - The authors estimated daily mercury intakes from seafood in 154 mothers residing in several cities and towns in Akita, Japan, to address the relationships between the reference dose (RfD of 0.1 microg/kg body weight per day, derived by US EPA) and daily mercury intakes, combined with hair mercury levels. The frequency and volume of seafood ingested by the subjects were examined using a food frequency questionnaire (FFQ) with 25 kinds of full-scale pictures including fish and shellfish items. Hair mercury concentrations in the mothers were also determined. The geometric means in the mothers were 15.3 (2.65-48.4) microg/day for daily mercury intakes from seafood, calculated on the basis of the references on mercury contents, and 1.73 (0.49-5.82) microg/g for hair mercury concentrations. The daily mercury intake was significantly correlated with hair mercury concentrations (Spearman rank correlation coefficient rs=0.335, p<0.001). No significant differences in mercury intakes were found either between mothers residing in fishing and non-fishing areas or between those in cities and towns (p>0.05). Assuming the methylmercury content rate of 75% in seafood and body weight of 55 kg, the mothers were estimated to ingest methylmercury of 0.21 microg/kg body weight per day. It is suggested that daily mercury intakes, calculated by the FFQ, reflect hair mercury levels, and there is no interregional difference in the daily mercury intake, unless special circumstances exist. Daily methylmercury intake in more than 90% of Japanese women may exceed the RfD.

  Source: Iwasaki, Y., M. Sakamoto, K. Nakai, T. Oka, M. Dakeishi, T. Iwata, H. Satoh, and K. Murata. 2003. Estimation of daily mercury intake from seafood in Japanese women: Akita cross-sectional study. Tohoku Journal of Experimental Medicine 200 (2): 67-73.




• Elements in fish of Malibu Creek and Malibu Lagoon near Los Angeles, California - This study was conducted to assess whether past discharges from a wastewater treatment plant increased metal pollutant loads in stream mobile species in a one-day baseline sampling study that included a coastal wetland. Mosquitofish (Gambusia affinis) of two sizes, black bullhead (Ameiurus melas), and crayfish (Pacifastacus leniusculus) were collected from Malibu Creek. California killifish (Fundulus parvipinnis) of three sizes, as well as arroyo chub (Gila orcutti) were sampled from Malibu Lagoon near Los Angeles, CA. Individual species at each locality were pooled by length, homogenized, digested by microwave wet ashing, and analyzed for 27 elements. Lagoon killifish 2.0-3.5 cm long contained levels of arsenic and lead above the levels for 95% of California fish, the EDL95. Black bullhead upstream of the discharge contained elevated levels of arsenic, chromium and selenium. Young mosquitofish (<3 cm in length) upstream of the discharge differed greatly in the order of abundance of their elements relative to larger mosquitofish and to other species collected. An additional sampling study is needed to determine if the wastewater treatment plant is a contrubuting source of pollution.

  Source: Moeller, A., S. MacNeil, R. Ambrose, and S. Que Hee. 2003. Elements in fish of Malibu Creek and Malibu Lagoon near Los Angeles, California. Marine Pollution Bulletin 46 (4): 424-429.




• Toxic metals in freshwater fish from the Zagreb area as indicators of environmental pollution - The authors’ study determined the levels of heavy metals and metalloids in freshwater fish from the Zagreb area. A total of 216 freshwater fish samples from five sites were examined, including the Sava river upstream from Zagreb, the Sava river at Zagreb, the Sava river downstream from Zagreb, Jarun Lake, and five "ecologic" fishponds from the Zagreb surroundings. Lead, cadmium, mercury and the metalloid arsenic were discovered in fish. Mean pooled levels of lead, cadmium and arsenic in all fish samples were 112.3 ppb, 8.5 ppob and 23.5 ppb, and samples did not exceed the allowed levels of 1,000 ppb, 100 ppb, and 200 ppb, respectively. In four fish samples, the levels of mercury exceeded the allowed limit of 500 micrograms/kg (509, 596, 605 and 788 ppb); however, the pooled mean level of mercury was 127.8 ppb. There were no major difference in the levels of heavy metals between the two fish families observed, although the levels of lead, cadmium and mercury were higher in the family Ictaluridae (144 vs. 107 ppb, 10.4 ppb vs. 8.2 ppb, and 153 ppb vs. 124 ppb, respectively). In contrast, the arsenic level was higher in the family Cyprinidae (23.8 ppb vs. 21.8 ppb). The Sava river at Zagreb is the main recipient of sewage and wastewater in the Republic of Croatia. Levels of heavy metals were within the allowed limits in all groups of freshwater fish samples, with the exception of 4 samples that contained moderately elevated levels of mercury. Study results suggest that only mercury could be considered a good indicator of environmental pollution, because higher levels of mercury were measured in the fish from the Sava river than in the fish from the Jarun Lake and fishponds from the Zagreb surroundings.

  Source: Bosnir, J., D. Puntaric, I. Skes, M. Klaric, S. Simic, I. Zoric, and R. Galic. 2003. Toxic metals in freshwater fish from the Zagreb area as indicators of environmental pollution. College Anthropology (27, Supplement 1): 31-39.




• PCBs in the karstic environment of Slovenia and Croatia as consequence of their accidental release - In two decades, there have been two serious incidents in the karstic area of Slovenia and Croatia which resulted in significant amount of polychlorinated biphenyls (PCBs) inflow into the bioecological cycle of the karstic environment. The first incident in Slovenia was at the beginning of the 1970s in the town of Semic, Bela Krajina. The second incident was due to the release of PCBs during war in Croatia. In 1996, waste oil and soil samples near damaged transformer stations were collected in the Delnice, Zadar, Sibenic, Split and Dubrovnik areas and were analyzed for PCBs. The authors provide a comparison of the PCB levels in various matrices (viz., water, sediment, fish, eggs, pork fat, pork meat, beef, chicken meat) of the Bela Krajina area from 1984-87 and in water, sediment, and fish for the Kupa river during 1985-87. Levels of PCBs in fish from Bela Krajina were the highest compared with other studied areas. The highest estimated PCB input into a critical population was also observed in Bela Krajina, although input of PCBs into the critical population in the area of the Kupa river and Zadar is not completely safe, because some part of population PCB intake level is above the recommended levels. Significant PCB levels were found in plasma of residents living in proximity to the Krupa River in Bela Krajina. The water bodies polluted most with PCBs in the karstic areas in Slovenia and Croatia are the rivers Krupa and Lahinja.

  Source: Picer, M. and I. Holoubek. 2003. PCBs in the karstic environment of Slovenia and Croatia as consequence of their accidental release. Special Issue: Recent Advances in the Environmental Toxicology and Health effects of PCBs. Part 1. 2nd PCB Workshop "Recent Advances in the Environmental Toxicology and Health Effects of PCBs". Brno, Czech Republic, 7-11 May, 2002. Vol. 12 (2): 86-93.




• The following five articles are from the 46th Conference on Great Lakes Research, held in conjunction with the 10th World Lake Conference on Global Threats to Large Lakes: Managing in an Environment of Instability and Unpredictability. June 22-26, 2003, Chicago, IL, USA. Vol. 43. {Abstracts Not Available}.
  

  McGraw, J., D. Waller, and J. Dellinger. 2003. Probabilistic risk assessment of PCB exposure to pregnant African American women through Great Lakes fish ingestion. Page 263.
  

  Chernyak, S., and J. Hickey. 2003. Trends of polybrominated flame retardants (PBDEs) and PCBs in fish collected from St. Clair/Detroit river ecosystem in 1980-2000. Page 248.
  

  Begnoche L., R. Quintal, S. Chernyak, and J. Hickey. 2003. Survey of chlorinated and brominated organic contaminants in Great Lakes lake sturgeon. Page 247.
  

  Powers, S. 2003. Modification of Index of Biotic Integrity for Russell Fork of Upper Big Sandy River System, Kentucky. Page 263.
  

  Button, D. 2003. Spatial co-occurrence of chemical "hotspots" in bed sediments and fish tissue in the Lake Erie basin based on multi-agency data from Canada and the United States, 1990-2001. Pages 191-192.

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