Newsletter - July 2005
- Advisory News
- Current Events, News and Journal Articles
- Meetings and Conferences
- For More Information
Note: The following summaries are based on articles from the press and from peer-reviewed publications, and they represent the opinions of the original authors. The views of authors expressed herein do not necessarily state or reflect those of the United States Government, and shall not be used for advertising or product endorsement purposes. Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government.
Recent Advisory News
- Fish consumption advisory introduced by Parks Canada
Jasper, Alberta Canada -Parks Canada has just added a fish consumption advisory to this year’s Fishing Regulations Summary pamphlet. The advisory is due to elevated mercury (Hg) fish tissue concentrations in some waterbodies in mountain national parks. Researchers working in the Jasper, Banff, Mt. Robson, and Yoho areas in 2003 found Hg levels in some fish that exceeded guidelines for “acceptable mercury levels”. Researchers contacted Jasper National Park (JNP) managers of their findings, and JNP notified Health Canada’s Bureau of Chemical Safety to request that a health risk assessment be conducted. Completed in 2004, the assessment resulted in JNP being notified that there was a potential human health risk for women of reproductive age and children who may be consuming large portions of fish. Parks Canada is recommending that women of reproductive age eat no more than four servings (serving size of 4 oz.) of fish from the mountain national parks per month. For children, the recommendation is for no more than three servings (serving size of 2.5 oz.) of fish per month.
Source: Kevin Gill, Jasper Booster, May 04, 2005.
Current Events, News and Journal Articles
- Campaign Launched to Compel Safeway to Post Seafood Mercury Warnings San Francisco, CA –An environmental organization has launched a campaign aimed at the national grocery retail chain Safeway for its failure to warn consumers nationwide about mercury (Hg)-contaminated seafood. The Turtle Island Restoration Network (TIRN) launched the campaign after talks with Safeway management ended in a stalemate. TIRN is requesting that Safeway expand its mercury-in-seafood health warning signs to all of its 1,802 Safeway-owned stores in both the United States and Canada. Safeway stores have warning signs posted at fish counters in their California stores for fish high in Hg, such as swordfish, shark, and tuna; however, these posting are only displayed in California, where such public notice is required under the state’s Proposition 65. Safeway is not posting the warning signs at any of its stores outside of California; therefore, TIRN believes Safeway is not living up to its own “Ingredients for Life” marketing campaign. In 2004, TIRN collected and tested fish from Safeway stores and found that 78% of samples exceeded the U.S. Food and Drug Administration (FDA) action level (1 ppm Hg). Some samples were as high as 1.5 ppm, 50% higher the FDA action level. The FDA warns mothers and women of childbearing age not to eat any swordfish, shark, king mackerel, and tilefish. Safeway however, does not feel it is necessary to warn customers of the dangers of eating swordfish and other fish that are high in Hg.
Source: For more information contact the TIRN. All Rights Reserved.
- Review of evidence: Are endocrine-disrupting chemicals in the aquatic environment impacting fish populations? The authors of this journal article address the following questions from information in the current literature: 1) Can endocrine-disrupting chemicals (EDCs) in the aquatic environment have the ability to impact the reproductive health and survival of various fish species, and 2) Are EDCs actually impacting the reproductive health and sustainability of indigenous fish populations? The authors suggest that laboratory experiment data support the hypothesis that EDCs can impact the reproductive health of fish species, but that evidence that EDCs are impacting the reproductive health and sustainability of indigenous fish populations is less convincing. The scarcity of evidence linking impacts of environmental EDCs with changes in reproductive success of fish populations may reflect a critical need for a dependable method to assess reproduction of fish in situ. The authors believe more studies are needed to investigate whether fish populations routinely exposed to EDCs in situ are experiencing changes in population structure.
Source: Mills, L.J. , and C. Chichester. 2005. Science of the Total Environment 343(1-3): 1-34.
- Methylmercury, fish consumption, and the precautionary principle. Based on information from the recent literature and epidemiological studies of the health effects of methylmercury, the authors considered several issues associated with the probabilistic assessment of the benefits of reducing mercury (Hg) emissions from U.S. coal-fired power plants. Exposure of the U.S. general population is considered on the national scale because of recent questions arising from survey and experimental data about the relative importance of local deposition of airborne Hg. Epidemiological studies have provided useful data, although safe levels of Hg exposure remain uncertain, partly because of other dietary considerations in the populations studied. For example, much of the seafood consumed in one major study was also contaminated with polychlorinated biphenyls (PCBs), similar to fish taken from some fresh waters of the United States. The primary epidemiological approach included cross-study comparisons in relation to mean exposures, rather than critiques of individual effects reported in each study. National U.S. exposures are viewed as being below the levels at which adverse health effects are reported. The authors’ analysis supports the conclusion that unilateral reduction of Hg emissions from U.S. coal-fired power plants alone is unlikely to result in significant public health benefits.
Source: Lipfert, F., S. Morris, T. Sullivan, P. Moskowitz, and S. Renninger. 2005. Journal of the Air and Waste Management Association 55 (4): 388-98.
- Mercury in freshwater fish of northeast North America—A geographic perspective based on fish tissue monitoring databases. The authors analyzed a large data set comprised of 15,305 records of fish tissue mercury (Hg) data from 24 studies across northeastern North America, from New York to Newfoundland. These data were analyzed to determine mean Hg levels for 40 fish species and associated fish families. Detailed analyses were conducted using data for 13 fish species. The authors found that Hg in fish varied by geographic area, waterbody type, and waterbody. Fish species with the highest mean Hg concentrations were muskellunge, walleye, white perch, and northern pike. Several fish species showed elevated Hg levels in reservoirs, relative to lakes and rivers. Mean Hg tissue levels for yellow perch and brook trout were mapped, showing that Hg levels in these species varied across northeastern North America. Certain geographic regions exhibited either below or above-average Hg concentrations in fish, while significant heterogeneity also was observed. The proportion of waterbodies exhibiting exceedances of U.S. Environmental Protection Agency’s (EPA's) criterion for fish methylmercury ranged from 14% for standard-length brook trout fillets to 42% for standard-length yellow perch fillets. The authors’ preliminary analysis showed that fish mercury concentrations were correlated to waterbody acidity and watershed size.
Source: Kamman, N.C., N.M. Burgess, C.T. Driscoll, H.A. Simonin, W. Goodale, J. Linehan, R. Estabrook, M. Hutcheson, A. Major, A.M. Scheuhammer, and D.A. Scruton. 2005. Ecotoxicology 14 (1-2): 163-80.
- Mercury concentrations in fish from forest harvesting and fire-impacted Canadian Boreal lakes compared using stable isotopes of nitrogen. Total mercury (Hg) concentrations were determined in several piscivorous and nonpiscivorous fish species from 38 drainage lakes in the Canadian Boreal Shield with clear-cut, burnt, or undisturbed catchments. Mercury levels increased with increasing fish trophic position, as estimated using stable isotopes of nitrogen. Mercury biomagnification varied from 22% to 29% in the three lake groups. Availability of Hg to organisms at the base of the food chain in lakes with cut catchments was higher than that in reference lakes. In cut lakes, Hg fish tissue concentrations were significantly related to ratio of the clear-cut area to lake area (or lake volume). In addition, both impact ratios were correlated with dissolved organic carbon. The authors’ findings suggest that differential loading of organic matter-bound Hg to lakes can affect Hg cycling. In addition, tissue Hg concentrations exceeded the advisory limit for human consumption (0.5 ppm wet wt) from the World Health Organization in all top predatory species (northern pike, walleye, and burbot) found in cut and in two partially burnt lakes. Elevated Hg concentrations in fish from forest-harvested and partially-burnt lakes may reflect increased exposure to Hg relative to that in lakes not having these watershed disturbances.
Source: Garcia, E. and R. Carignan. 2005. Environmental Toxicology and Chemistry 24 (3): 685-93.
- Polybrominated diphenyl ethers (PBDEs) in freshwater mussels and fish from Flanders, Belgium. Concentrations and the distribution of PBDEs in zebra mussels and several freshwater fish species (eel, carp, and gibel carp) were studied for different sites in Flanders, Belgium. Other organohalogenated contaminants, such as PCBs, p, p-DDE, and hexachlorobenzene (HCB) were also analyzed, and their relationship with PBDEs was investigated. At most sites, individual PBDE congeners were present at detectable levels in mussel tissue, with the mean PBDE concentration ranging from 0.15 to 1.8 ppb wet weight (ww). PCB levels in mussels ranged from 6.2 to 102 ppb (ww). HCB and p, p-DDE could be detected in mussels from most sites, with mean values ranging from below the limit of quantification (LOQ) to 0.58 ppb (ww) and from 0.66 to 6.5 ppb (ww), respectively. Except for one site (Blokkersdijk, Antwerp), where PBDEs were below the LOQ in carp muscle, all fish samples contained detectable PBDE levels, with the highest concentrations (14 ppb ww) being detected in eel liver from Watersportbaan (Ghent). Sampled sites covered a broad concentration range of organohalogenated pollutants, with the highest values being consistently measured in eel liver. Correlations between PBDEs and organochlorine pollutants were low, and most were not significant. The results suggest that the exposure to contaminants arises from local sources with different signatures of PBDEs and organochlorine pollutants.
Source: Covaci, A., L. Bervoets, P. Hoff, S. Voorspoels, J. Voets, K. Van Campenhout, R. Blust, and P. Schepens. 2005. Journal of Environmental Monitoring 7 (2): 132-6.
- Reduction in organic contaminant exposure and resultant hepatic hydropic vacuolation in winter flounder (Pseudopleuronectes americanus) following improved effluent quality and relocation of the Boston sewage outfall into Massachusetts Bay, USA: 1987-2003. Effluent upgrades for metropolitan Boston have included toxicant reduction, primary and secondary sewage treatment, and outfall extension. Between 1992 and 2003, winter flounder at five stations were surveyed annually for liver and muscle chemical contaminant concentrations, chronic hepatic sub-lethal impacts of polynuclear and halogenated aromatic hydrocarbons, and metals. Trends in flounder availability and fin condition were also examined. In 1988, 12% of adult winter flounder in Boston Harbor exhibited hepatic neoplasms, and up to 80% had hepatic hydropic vacuolation (HV). Tumor prevalence and HV had dropped to 0-2% and <50%, respectively, by 1996. Although the prevalence of HV has remained consistent with lower hydrocarbon loading and tissue levels, tumors have been absent since the initial studies. Contaminant concentrations and HV also fell with distance from the Boston outfall. The outfall extension was activated in 2000, and there has been no significant change in flounder liver health at the new outfall site.
Source: Moore, M., L. Lefkovitz, M. Hall, R. Hillman, D. Mitchell, and J. Burnett. 2005. Marine Pollution Bulletin 50 (2): 156-66.
- Measurement of organochlorines in commercial, over-the-counter fish oil preparations: Implications for dietary and therapeutic recommendations for omega-3 fatty acids and a review of the literature. The American Heart Association (AHA) recommends consumption of fish high in omega-3 fatty acids to reduce the risk of coronary artery disease; however, some fish species contain environmental contaminants, such as mercury (Hg), PCBs, and organochlorine pesticides, which may negate the beneficial cardiovascular effects of fish meals. Contaminant levels are dependent on both the fish source and the specific contaminant, and neither farm-raised nor wild fish are contaminant free. Fish oil supplements also prevent the progression of coronary artery disease and reduce cardiovascular mortality. Very little data exist on the level of contaminants in fish oil. In a previous study, the authors reported that the amount of Hg in five over-the-counter brands of fish oil was negligible. To determine the levels of PCBs and other organochlorines in five over-the-counter fish oil preparations, the contents of five commercial fish oil brands were sent for analysis. Fish oil supplements are more healthful than the consumption of fish high in organochlorines because supplements provide the benefits of omega-3 fatty acids without the risk of some chemical contaminants.
Source: Melanson, S.F., E.L. Lewandrowski, J.G. Flood, and K.B. Lewandrowski. 2005. Archives of Pathology and Laboratory Medicine 129 (1): 74-7.
- Quantification and speciation of mercury and selenium in fish samples of high consumption in Spain and Portugal. Mercury (Hg) and selenium (Se) concentrations were analyzed to evaluate human exposure through the pathway of fish consumption in Spain and Portugal. Atomic fluorescence spectroscopy (AFS) was applied in a cold vapor mode for total Hg quantification and was also hyphenated to gas chromatography (GC) to achieve the speciation of organomercurial species. Results showed the highest concentrations of Hg in swordfish and tuna (0.47 and 0.31 ppm, respectively), and much lower levels in sardine, mackerel shad, and octopus (0.048, 0.033, and 0.024 ppm, respectively). Approximately 93-98% of Hg in the fish samples was in the organic form. Methylmercury (MeHg) was the only contaminant found in the three fish species with high mercury content. Total Se levels were high in sardine, swordfish, and tuna (0.43, 0.47, and 0.92 ppm, respectively), but low in mackerel shad and octopus (0.26 and 0.13 ppm, respectively). Speciation of Se compounds was done by high-performance liquid chromatography (HPLC) in association with inductively coupled plasma mass spectrometry (LC-ICP-MS). The only Se compound found was selenomethionine (SeMet), which was identified in the fish samples with higher Se content. Of the fish surveyed, sardines had the most favorable Se: Hg and SeMet: MeHg molar ratios; thus, its consumption seems to be preferable.
Source: Cabanero, A.I., C. Carvalho, Y. Madrid, C. Batoreu, and C.Camara. 2005. Biological Trace Element Research 103 (1): 17-35.
- Practical applications of fish oil (omega-3 fatty acids) in primary care. Fish oil (omega-3 fatty acids) has been studied for more than three decades; however, recent concerns about mercury (Hg) and environmental toxicants have clouded fish oil's potential beneficial health effects. The author’s aim was to review practical applications of fish oil for the primary care physician. The author searched PubMed search using the key words “fish oil,” “docosahexaenoic,” and “eicosapentaenoic” in title/abstract, and limited the search to human clinical trials. Publications were scanned for relevant sources. For secondary prevention of cardiovascular disease, 1 g of fish oil has been shown to reduce overall and cardiovascular mortality, myocardial infarctions, and sudden cardiac death. Higher doses of fish oil may be used for its potent triglyceride-lowering effects and for patients with rheumatoid arthritis to reduce nonsteroidal anti-inflammatory use. In infant formulas, omega-3 fatty acids have shown benefits in infant neural growth and development. Because of the potential health benefits of fish, women of childbearing age should be encouraged to eat 1 to 2 low-mercury fish meals per week. For the primary care physician, fish oil has numerous practical applications. Understanding the diverse clinical research of omega-3 fatty acids and fish oil is important in determining its role in primary care practices.
Source: Oh, R. 2005. Journal of the American Board of Family Practitioners 18 (1): 28-36.
- Effect of concomitant consumption of fish oil and vitamin E on production of inflammatory cytokines in healthy elderly humans. It has been suggested that some of the beneficial effects of fish oil include reducing inflammatory and cardiovascular diseases, which occur through fish oil's inhibition of synthesis of pro-inflammatory cytokines. Epidemiological studies have revealed a relationship between increased intake of vitamin E in diet and reduced risk of cardiovascular disease. Because pro-inflammatory cytokines have been indicated in pathogenesis of cardiovascular diseases, the current study was designed to determine the effect of concomitant consumption of fish oil and vitamin E on interleukin, as well as tumor necrosis factor alpha production by peripheral blood mononuclear cells. Healthy elderly patients consumed fish oil, plus varied doses of vitamin E, for 3 months. In general, results indicated that fish oil inhibited production of pro-inflammatory cytokines, and that vitamin E did not interfere with this effect of fish oil. Vitamin E supplementation at a 200-mg/day dose might further add to the fish oil-induced inhibition of cytokines.
Source: Wu, D., S.N. Han, M. Meydani, and S.N. Meydani. 2004. Annuals of the New York Academy of Science 1031: 422-4.
- Determination of inorganic and total mercury in biological samples treated with tetramethylammonium hydroxide by cold vapor atomic absorption spectrometry using different temperatures in the quartz cell. The authors proposed a very simple procedure for the determination of total and inorganic mercury (Hg) in biological materials. The concentration of organic mercury (methylmercury) was obtained from the difference between the total and inorganic Hg values. Samples were treated at room temperature with tetramethylammonium hydroxide (TMAH). Inorganic Hg was analyzed by cold vapor atomic absorption spectrometry (CV-AAS), keeping the quartz cell at room temperature; total Hg was analyzed using the same technique, but heating the quartz cell in an air–acetylene flame. By analyzing several biologically certified reference materials, it was evident to the authors that the difference between total and inorganic Hg corresponded to methylmercury. Cold vapor graphite furnace atomic absorption spectrometry (CV-GF-AAS), with retention of the vapor in a heated Au-treated graphite tube, was used to optimize the vapor generation conditions and to determine total Hg. The concentrations obtained by both techniques were in agreement with the certified reference values or with differences of the certified values for total, Hg2+ and CH3Hg+. The detection limits in the sample were: 0.13 ppm for total Hg and 0.025 ppm for Hg2+ by CV-AAS. The detection limit for total Hg by CV-GF-AAS was 0.001 ppm. This method provided important information on Hg speciation.
Source: Torres, D.P., M.A. Vieira, A.S. Ribeiro and A.J. Curtius. 2005. Journal of Analytical Atomic Spectrometry 20 (4), 289–294.
- Screening of fish tissue for methylmercury using the enzyme invertase in a solvent interface. The authors detail a rapid screening system for extracting and determining methylmercury concentrations in fish tissue samples. A novel clean-up procedure was developed that has two immiscible phases: an organic phase containing methylmercury and an aqueous phase containing invertase. Methylmercury was selectively extracted from the organic into the aqueous phase by an irreversible reaction with thiol groups of invertase. The resulting inhibition of enzyme activity serves as a measure of methylmercury concentration. Enzyme activity was measured using a spectrophotometric method. After optimization, including pH, substrate concentration, and enzyme reaction time, methylmercury can be analyzed in the ppb range. Concentrations of 10 ppb methylmercury in the extract corresponded to 0.2 ppm of methylmercury in fish.
Source: Mohammadi, H., A. Amine, A. Ouarzane, and M. El Rhazi. 2005. Microchemica Acta 149 (3-4): 251-257.
Meetings and Conferences
- American Fisheries Society 135th Annual Meeting. The 135th Annual Meeting of the AFS will be held at the Egan Convention Center and Performing Arts Center in Anchorage, Alaska September 11-15, 2005. The meeting’s theme will be “Creating A Fisheries Mosaic: Connections Across Jurisdictions, Disciplines, and Cultures.” Get more information and register here: http://www.wdafs.org/Anchorage2005/index.htm
- EPA Forum on Chemical Contaminants in Fish. The 8th Annual Forum on Chemical Contaminants in Fish will be held at the Marriott Baltimore Inner Harbor at Camden Yards in Baltimore, Maryland September 18-21, 2005. Get more information, submit a poster, and register here: http://epa.gov/ost/fish/forum/2005/
- Society of Environmental Toxicology and Chemistry (SETAC). November 13-17, 2005, Baltimore, MD. Get more information here: http://www.setac.org/baltimore/baltimore.html
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