Experimental Evidence of a Linear Relationship between Inorganic Mercury Loading and Methylmercury Accumulation by Aquatic Biota

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• 作者：Diane M. Orihel ; Michael J. Paterson ; Paul J. Blanchfield ; R. A (Drew) Bodaly ; Holger Hintelmann
• 刊名：Environmental Science & Technology
• 出版年：2007
• 出版时间：July 15, 2007
• 年：2007
• 卷：41
• 期：14
• 页码：4952 - 4958
• 全文大小：171K
• 年卷期：v.41,no.14(July 15, 2007)
• ISSN：1520-5851

文摘

Developing effective regulations on mercury (Hg) emissionsrequires a better understanding of how atmospheric Hgdeposition affects methylmercury (MeHg) levels in aquaticbiota. This study tested the hypothesis that MeHgaccumulation in aquatic food webs is related to atmosphericHg deposition. We simulated a range of inorganic Hgdeposition rates by adding isotopically enriched Hg(II) (90.9%²⁰²Hg) to 10-m diameter mesocosms in a boreal lake.Concentrations of experimentally added ("spike") Hg weremonitored in zooplankton, benthic invertebrates, andfish. Some Hg(II) added to the mesocosms was methylatedand incorporated into the food web within weeks,demonstrating that Hg(II) deposited directly to aquaticecosystems can become quickly available to biota.Relationships between Hg(II) loading rates and spikeMeHg concentrations in zooplankton, benthic invertebrates,and fish were linear and significant. Furthermore, spikeMeHg concentrations in the food web were directlyproportional to Hg(II) loading rates (i.e., a percent changein Hg(II) loading rate resulted in, statistically, the samepercent change in MeHg concentration). This is the firstexperimental determination of the relationship between Hg(II) loading and MeHg bioaccumulation in aquatic biota.We conclude that changes in atmospheric Hg depositioncaused by increases or decreases in Hg emissions willultimately affect MeHg levels in aquatic food webs.