کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8910966 | 1637935 | 2018 | 41 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Mercury flux from salt marsh sediments: Insights from a comparison between 224Ra/228Th disequilibrium and core incubation methods
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موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
ژئوشیمی و پترولوژی
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![عکس صفحه اول مقاله: Mercury flux from salt marsh sediments: Insights from a comparison between 224Ra/228Th disequilibrium and core incubation methods Mercury flux from salt marsh sediments: Insights from a comparison between 224Ra/228Th disequilibrium and core incubation methods](/preview/png/8910966.png)
چکیده انگلیسی
In aquatic environments, sediments are the main location of mercury methylation. Thus, accurate quantification of methylmercury (MeHg) fluxes at the sediment-water interface is vital to understanding the biogeochemical cycling of mercury, especially the toxic MeHg species, and their bioaccumulation. Traditional approaches, such as core incubations, are difficult to maintain at in-situ conditions during assays, leading to over/underestimation of benthic fluxes. Alternatively, the 224Ra/228Th disequilibrium method for tracing the transfer of dissolved substances across the sediment-water interface, has proven to be a reliable approach for quantifying benthic fluxes. In this study, the 224Ra/228Th disequilibrium and core incubation methods were compared to examine the benthic fluxes of both 224Ra and MeHg in salt marsh sediments of Barn Island, Connecticut, USA from May to August, 2016. The two methods were comparable for 224Ra but contradictory for MeHg. The radiotracer approach indicated that sediments were always the dominant source of both total mercury (THg) and MeHg. The core incubation method for MeHg produced similar results in May and August, but an opposite pattern in June and July, which suggested sediments were a sink of MeHg, contrary to the evidence of significant MeHg gradients between overlying water and porewater at the sediment-water interface. The potential reasons for such differences are discussed. Overall, we conclude that the 224Ra/228Th disequilibrium approach is preferred for estimating the benthic flux of MeHg and that sediment is indeed an important MeHg source in this marshland, and likely in other shallow coastal waters.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Geochimica et Cosmochimica Acta - Volume 222, 1 February 2018, Pages 569-583
Journal: Geochimica et Cosmochimica Acta - Volume 222, 1 February 2018, Pages 569-583
نویسندگان
Xiangming Shi, Robert P. Mason, Matthew A. Charette, Nashaat M. Mazrui, Pinghe Cai,