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Characteristics of sediment affecting monomethylmercury accumulation in benthic fish of the Mekong Delta
Author(s) -
Choi Hyojung,
Jeong Eunji,
Nguyen Viet Huu,
Hanh Dang Vu Bich,
Dan Nguyen Phuoc,
Shin KyungHoon,
Han Seunghee
Publication year - 2019
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 - 10.1002/etc.4327
Subject(s) - sediment , bioaccumulation , delta , total organic carbon , benthic zone , tributary , environmental science , environmental chemistry , mercury (programming language) , hydrology (agriculture) , geology , chemistry , oceanography , geography , paleontology , cartography , geotechnical engineering , aerospace engineering , computer science , engineering , programming language
The Mekong River Delta (Vietnam) is a flat, low‐lying area formed by a dense network of main tributaries of the Tien and Hau Rivers, providing a nourishing habitat for aquatic organisms. A sediment survey of the total mercury (Hg), monomethylmercury (MMHg), and geochemical variables was carried out from the coast to 131 km upriver to establish an overview of the environmental factors affecting the bioaccumulation of Hg and MMHg in delta fish. The survey results revealed that the total Hg (12–90 ng g –1 ) and MMHg (0.014–1.5 ng g –1 ) concentrations were in the range of uncontaminated sediment. Statistical analysis using various geochemical factors demonstrated that sediment MMHg concentrations and fractions of MMHg over total Hg in sediment were higher at sites with higher total organic carbon (TOC) and total nitrogen sites. The current levels of TOC in Mekong Delta sediment are relatively low (0.2–1.5%); however, expanding dam constructions and aquacultures related to salinity intrusion are reinforcing the carbon burial rate by increasing the fine fractions. Based on the positive relationship found between MMHg and TOC in sediment, proper management efforts are necessary to reduce MMHg production in the Mekong River Delta sediment. Environ Toxicol Chem 2019;38:503–510. © 2018 SETAC