Speciation and Cycling of Mercury in Lavaca Bay, Texas, Sediments

详细信息    查看全文

• 作者：Nicolas S Bloom ; Gary A. Gill ; Steven Cappellino ; Charles Dobbs ; Larry McShea ; Charles Driscoll ; Robert Mason ; and John Rudd
• 刊名：Environmental Science & Technology
• 出版年：1999
• 出版时间：January 1, 1999
• 年：1999
• 卷：33
• 期：1
• 页码：7 - 13
• 全文大小：322K
• 年卷期：v.33,no.1(January 1, 1999)
• ISSN：1520-5851

文摘

Sediment depth profiles of total mercury (THg) andmonomethylmercury (MMHg) were collected at 15 sites inan anthropogenically contaminated estuarine system(Lavaca Bay, TX). THg in the solid phase increased withdepth to a maximum located at 10-30 cm, which correspondsto historic industrial discharges to the bay. MMHg inthe solid phase was highest in the upper 0-3 cm of thecores, decreasing rapidly with depth. The MMHg contentof the surface sediment was a narrowly constrainedfraction of the total (0.65 ± 0.34%) over a range of sedimenttypes, while making up only 0.01-0.05% of THg at depth.Porewater concentrations exhibited trends similar to but moreexaggerated than in the solid phase. The distributioncoefficients (log K_d) for inorganic Hg (IHg = THg - MMHg)were similar in most samples, averaging 4.89 ± 0.43.The log K_d for MMHg averaged 2.70 ± 0.78 over all sitesand depths but exhibited a subsurface minimum of 2.29 ±0.67 at the point of maximum dissolved Fe. A timeseries showed a maximum in both solid phase and porewaterMMHg during the early spring, followed by a decreasethroughout the remainder of the year.