Newsletter—October 2009

Arsenic in seafood may pose a health risk

New research suggests that certain forms of organic arsenic, which appear in seafood and are thought to be harmless, might actually be toxic or break down in to toxic components in the body. The small study of just 6 subjects, which used synthetic forms of organic arsenic, also found that while arsenic passes quickly through some people, it seems to linger inside others for an extended period. Researchers have yet to establish that arsenic breakdown products pose a health risk to humans or that naturally occurring organic arsenic breaks down in the same way as the synthetic form used in the study. Arsenic levels in seafood are not currently regulated in most places, although the European Food Safety Authority is considering regulating.

Source: Discovery News, 9/4/2009.

EPA rule limits 3 pesticides near salmon waters

The Environmental Protection Agency (EPA) announced new limits on the use of chlorpyrifos, diazinon and malathion near salmon waters in Washington, California, Oregon and Idaho. These chemicals have been found by the U.S. Geological Survey to interfere with salmon's sense of smell, making it harder for them to find food, avoid predators and return to native waters to spawn. The new rules prohibit the use of these pesticides within 100 to 1,000 feet of salmon waters, depending on size of the river or stream, application rate and other criteria.

Source: Associated Press, 9/12/2009.

Protective effects of selenium in Inuit exposed to PCBs

The authors collected blood samples from 83 adult Inuit from Salluit, Northern Canada who are exposed to high levels of polychlorinated biphenyls (PCBs) and selenium in their traditional foods (including blubber from sea mammals and fatty fish). The authors also measured DNA adducts as biomarkers of carcinogenesis in the study subjects. Analysis of the results suggests that increasing selenium has a mitigating effect in reducing DNA adducts and therefore, possible negative effects of PCBs were not seen.

Ravoori, S., C. Srinivasan, et al. (2009). "Protective effects of selenium against DNA adduct formation in Inuit environmentally exposed to PCBs." Environ Int Sep 5. [Epub ahead of print].

A new and cost-effective method for methyl mercury analysis in saltwater fish

The authors describe a new cost-effective method for the analysis of methyl mercury (MeHg) in seawater fish muscle. This method uses microwave-assisted extraction with acidic solution (HCl), addition of toluene, and subsequent extraction with cysteine acetate solution where only MeHg is present because of its affinity for cysteine groups. Validation, precision, and accuracy of the method were evaluated and monitored with a tuna fish certified reference material (CRM 463) containing MeHg.

Carbonell, G., J. C. Bravo, et al. (2009). "A New Method for Total Mercury and Methyl Mercury Analysis in Muscle of Seawater Fish." Bulletin of Environmental Contamination and Toxicology [Bull. Environ. Contam. Toxicol.]. 83(2): 210-213.

A review of aquaculture: toxicological issues

This review covers the toxicological, environmental, and health concerns of aquaculture practices. The authors found that although the public often perceives that farmed fish are 'cleaner' than comparable wild fish, some farmed fish have much higher body burdens of natural and man-made toxic substances, including pesticides and persistent organic pollutants, than do wild fish.

Cole, D. W., R. Cole, et al. (2009). "Aquaculture: Environmental, toxicological, and health issues." International Journal of Hygiene and Environmental Health [Int. J. Hyg. Environ. Health]. 212(4): 369-377.

Eat fish or take a fish oil supplement?

Many researchers are now in agreement that the consumption of long-chain omega-3 polyunsaturated fatty acids (LCn-3PUFAs) in fish is important for the prevention of cardiovascular disease. The author reviews the epidemiology of fish or LCn-3PUFAs with major cardiovascular disease risk factors, and also discusses the possible difference between whole fish as a nutrient package and fish oil supplements as a source of LCn-3PUFAs with respect to prevention of cardiovascular disease.

He, K. (2009). "Fish, long-chain omega-3 polyunsaturated fatty acids and prevention of cardiovascular disease--eat fish or take fish oil supplement?" Prog Cardiovasc Dis 52(2): 95-114.

PCBs in chinook salmon migrating through a contaminated urban estuary

The authors examined bioaccumulation of PCBs for hatchery-raised and wild ocean-type juvenile chinook salmon outmigrating through the Lower Duwamish Waterway (LDW), a contaminated urban estuary in Seattle, WA, USA. The salmon on the east side of the LDW accumulated three to five times more PCBs than fish on the west side, which is supported by an almost identical difference in mean sediment PCB concentrations. These data support the authors’ hypothesis that for most of the spring and early summer, juvenile chinook were likely segregated between the east and west side of the LDW, but may have crossed the channel later in the year as larger fish.

Meador, J. P., G. M. Ylitalo, et al. (2009). "Bioaccumulation of polychlorinated biphenyls in juvenile chinook salmon (Oncorhynchus tshawytscha) outmigrating through a contaminated urban estuary: dynamics and application." Ecotoxicology Aug 14. [Epub ahead of print].

Spatial trends of mercury in sport fish in the Sacramento-San Joaquin Delta watershed

The authors surveyed more than 4,000 fish (from 31 different species) in the Sacramento-San Joaquin Delta watershed for total mercury in individual muscle filets. Largemouth bass and striped bass were the most contaminated, averaging 0.40 parts per million (ppm), while redear sunfish, bluegill and rainbow trout exhibited the lowest (<0.15 ppm) concentrations. The authors found significant regional differences in mercury among largemouth bass, with concentrations on the Cosumnes and Mokelumne rivers significantly higher than the central and western Delta, perhaps due to spatially variable predator-prey relationships.

Melwani, A. R., S. N. Bezalel, et al. (2009). "Spatial trends and impairment assessment of mercury in sport fish in the Sacramento-San Joaquin Delta watershed." Environmental Pollution [Environ. Pollut.]. 157(11): 3137-3149.

Health impacts in the immediate aftermath of the coal ash spill in Kingston, Tennessee

The authors discuss the potential environmental and health impacts of the coal ash spills at the Tennessee Valley Authority (TVA) Kingston (Tennessee) coal-burning power plant. Mercury and arsenic present in the coal ash may accumulate in the river sediments and lead to formation of methylmercury.

Ruhl, L., A. Vengosh, et al. (2009). "Survey of the potential environmental and health impacts in the immediate aftermath of the coal ash spill in Kingston, Tennessee." Environ Sci Technol 43(16): 6326-33.

Trends in dioxin levels in human blood 1987-2002

This study assessed temporal trends for human levels of polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) between 1987 and 2002 among 26 men from Sweden. Nine of the men did not eat fatty fish from the Baltic Sea, eight had a moderate intake, and nine were high consumers. The authors found that, while concentrations of total PCDD and total PCDF in blood samples did not significantly change over the 15-year period, some specific congeners did change.

Rylander, L., L. Hagmar, et al. (1557). "Intra-individual variations and temporal trends in dioxin levels in human blood 1987-2002." Chemosphere [Chemosphere] 76(11): 1557-1562.

2009 National Forum on Contaminants in Fish

November 2–5, 2009, Portland, Oregon. For more information, please visit:
http://www.epa.gov/waterscience/fish/forum/2009/

SETAC North America 30th Annual Meeting

Human-Environment Interactions: Understanding Change in Dynamic Systems

November 19–23, 2009, New Orleans, Louisiana. For more information, please visit:
http://neworleans.setac.org/

December 2009

Society for Risk Analysis Annual Meeting

December 6–9, 2009, Baltimore, Maryland. For more information, please visit:
http://www.sra.org/events_2009_meeting.php

March 2010

Society of Toxicology Annual Meeting

March 7–11, 2010, Salt Lake City, Utah. For more information, please visit:
http://www.toxicology.org/AI/MEET/AM2010