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Inorganic mercury binding with different sulfur species in anoxic sediments and their gut juice extractions
Author(s) -
Zhong Huan,
Wang WenXiong
Publication year - 2009
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/08-539.1
Subject(s) - bioavailability , anoxic waters , chemistry , environmental chemistry , sulfide , mercury (programming language) , sulfur , sorption , sediment , extraction (chemistry) , pyrite , chromatography , mineralogy , geology , biology , paleontology , bioinformatics , organic chemistry , adsorption , computer science , programming language
Abstract A Abstract—To investigate the roles of different sulfur (S) species in controlling the partitioning and bioavailability of inorganic mercury (Hg) in anoxic sediments, we examined the differential binding of Hg with three key S species in anoxic sediment (mackinawite [FeS], pyrite [FeS 2 ], and S 2− ) and then quantified their extraction by the gut juice of deposit‐feeding sipunculans Sipunculus nudus. A sequential extraction method was simultaneously used to distinguish Hg sorption with different sediment components. All three Scontaining sediment components could lead to a high binding of Hg in sediments, but most Hg was sorbed with FeS or FeS 2 instead of formation of Hg sulfide despite the presence of S 2− or humic acid. The gut juice extraction was relatively low and constant whenever FeS and FeS 2 were in the sediment, indicating that both FeS and FeS 2 controlled the Hg gut juice extraction and thus bioavailability. Mercury sorbed with FeS 2 had higher gut juice extraction than that with FeS, while Hg sulfide was not extracted, strongly suggesting that Hg sorbed with FeS 2 was more bioavailable than that with other S species. Mercury sorbed with FeS had very low bioavailability to sipunculans at a low Hg:S ratio in the sediment but was more bioavailable with increasing Hg:S ratio up to a maximum (∼1:10, mole based). The present study showed that different S species (FeS, FeS 2 ) and Hg:S ratios significantly affected the binding and bioavailability of Hg in anoxic sediments.