Mercury distribution, speciation and bioavailability in sediments from the Pearl River Estuary, Southern China

• Published in: Marine pollution bulletin Vol. 64; no. 8; pp. 1699 - 1704
• Main Authors: Yu, Xiujuan, Li, Hengxiang, Pan, Ke, Yan, Yan, Wang, Wen-Xiong
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-08-2012
• Subjects: Bioavailability; Brackish; Carbon; China; Environmental Monitoring; Estuaries; Extraction; Freshwater; Geologic Sediments - chemistry; Gut juice; Marine; Mercury; Mercury - analysis; organic matter; Pearl River Estuary; Rivers; Rivers - chemistry; Sediment; Sediments; Sequential extraction; Speciation; Water Pollutants, Chemical - analysis; water pollution; Water Pollution, Chemical - statistics & numerical data; China; China, People's Rep., Zhu R; China, People's Rep; Gut juice; Sequential extraction; Sediment; Mercury; Pearl River Estuary
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2012.03.018

► Total Hg in the Pearl River Estuary surface sediments displayed large spatial variations. ► There was accelerating input of Hg into the Pearl River Estuary in the past decades. ► The organo-chelated and strong-complexed Hg were the dominant Hg species. ► The low extraction of Hg from sediments indicated the low bioavailability of Hg. ► Organic matter strongly influenced the concentration, distribution, and extractability of Hg.
Surface sediments and sediment cores collected from the Pearl River Estuary (PRE) were analyzed for total mercury (THg) concentrations and speciation using a sequential extraction method. The mobility of Hg in sediments was also assessed using a series of single extraction methods. The surface sediments from the PRE showed slightly elevated levels of Hg, with concentrations ranging from 109 to 453ng/g. The vertical profile of THg in sediment cores indicated an accelerated input of Hg over the past decades. The organo-chelated and strong-complexed Hg species were the dominant Hg species in the sediments, while the more mobile phases of Hg made up less than 0.5% of THg. Less than 10% of the Hg in the sediments was extracted by single extraction, depending on the extractant employed. Significant relationships were found between the total organic carbon and THg, geochemical speciation, and extractability, indicating the important role of organic matter in controlling the distribution, mobility, and bioavailability of Hg in sediments.