Time Trends of Methylmercury in Walleye in Northern Wisconsin: A Hierarchical Bayesian Analysis

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• 作者：Eric R. Madsen ; Hal S. Stern
• 刊名：Environmental Science & Technology
• 出版年：2007
• 出版时间：July 1, 2007
• 年：2007
• 卷：41
• 期：13
• 页码：4568 - 4573
• 全文大小：223K
• 年卷期：v.41,no.13(July 1, 2007)
• ISSN：1520-5851

文摘

Methylmercury data from walleye fillets collected bymultiple agencies from northern Wisconsin lakes from1982 to 2005 were examined for regional time trends.Hierarchical Bayesian methods were used to modeldependencies and provide probability statements forparameters pertaining to individual lakes and the regionas a whole. A missing data mechanism allowed the sex ofthe fish to be included as a predictor since the sexesgrow at different rates. A slight regional decreasein methylmercury of 0.60% annually was found, consistentwith declining atmospheric mercury deposition. Methylmercury was estimated to have decreased in 77% of the420 lakes from which walleye were sampled, althoughuncertainty regarding time trends was greater for mostindividual lakes than for the region as a whole. Methylmercuryin walleye varied widely from lake to lake, but generallyaccumulated in the fish at similar rates by length afteraccounting for differences in sex. Slower-growing malewalleye had higher methylmercury concentrationsthan females for a given length, and skin-on fillets were16% lower in methylmercury than skin-off fillets.