Evaluation of Mercury Exposure Reduction through a Fish Consumption Advisory Program for Anishinaabe Tribal Members in Northern Wisconsin, Michigan, and Minnesota

The Great Lakes Indian Fish and Wildlife Commission has an extensive program to inform Anishinaabe tribal members from northern Wisconsin, Michigan, and Minnesota who harvest and consume walleye about the health risks of consuming these fish, and to encourage harvest and consumption practices that reduce exposure to MeHg. We report here the results of a probabilistic analysis of exposure to methyl mercury (MeHg) among tribal members who consume walleye. The model predicts that the potential for greatest exposures to MeHg occur among women of child-bearing age and children who consume large walleye from lakes that contain heavily contaminated (MeHg concentration >0.5 mg/kg) fish. The analysis allows GLIFWC to evaluate, focus, and fine-tune its initiatives to protect the health of tribal members in ways that result in exposure and risk reduction for tribal harvesters, women of child-bearing age, and children, while maintaining important tribal lifeways, which include the harvest and consumption of walleye

Risk-Based Consumption Advice for Farmed Atlantic and Wild Pacific Salmon Contaminated with Dioxins and Dioxin-like Compounds

We reported recently that several organic contaminants occurred at elevated concentrations in farmed Atlantic salmon compared with concentrations of the same contaminants in wild Pacific salmon [Hites et al. Science 303:226–229 (2004)]. We also found that polychlorinated biphenyls (PCBs), toxaphene, dieldrin, dioxins, and polybrominated diphenyl ethers occurred at higher concentrations in European farm-raised salmon than in farmed salmon from North and South America. Health risks (based on a quantitative cancer risk assessment) associated with consumption of farmed salmon contaminated with PCBs, toxaphene, and dieldrin were higher than risks associated with exposure to the same contaminants in wild salmon. Here we present information on cancer and noncancer health risks of exposure to dioxins in farmed and wild salmon. The analysis is based on a tolerable intake level for dioxin-like compounds established by the World Health Organization and on risk estimates for human exposure to dioxins developed by the U.S. Environmental Protection Agency. Consumption of farmed salmon at relatively low frequencies results in elevated exposure to dioxins and dioxin-like compounds with commensurate elevation in estimates of health risk

Bond length contraction in Au nanocrystals formed by ion implantation into thin SiO[sub 2]

Au nanocrystals (NCs) fabricated by ion implantation into thin SiO₂ and annealing were investigated by means of extended x-rayabsorption fine structure (EXAFS)spectroscopy and transmission electron microscopy. A bond length contraction was observed and can be explained by surface tension effects in a simple liquid-drop model. Such results are consistent with previous reports on nonembedded NCs implying a negligible influence of the SiO₂ matrix. Cumulant analysis of the EXAFS data suggests surface reconstruction or relaxation involving a further shortened bond length. A deviation from the octahedral closed shell structure is apparent for NCs of size 25Å.P. K. is grateful to the Humboldt Foundation in Germany for support. P.K., B.J., A.C., C.J.G., G.d.M.A., G.J.F., and M.C.R. were supported by the Australian Synchrotron Research Program