title: Simultaneous determination of mercury and organic carbon in sediment and soils using a direct mercury analyzer based on thermal decomposition-atomic absorption spectrophotometry.
abstract: The purpose of this work was to study the feasibility of using a direct mercury analyzer (DMA) to simultaneously determine mercury (Hg) and organic matter content in sediment and soils. Organic carbon was estimated by re-weighing the sample boats post analysis to obtain loss-on-ignition (LOI) data. The DMA-LOI results were statistically similar (p<0.05) to the conventional muffle furnace approach. A regression equation was developed to convert DMA-LOI data to total organic carbon (TOC), which varied between 0.2% and 13.0%. Thus, mercury analyzers based on combustion can provide accurate estimates of organic carbon content in non-calcareous sediment and soils; however, weight gain from moisture (post-analysis), measurement uncertainty, and sample representativeness should all be taken into account. Sediment cores from seasonal wetland and open water areas from six oxbow lakes in the Mississippi River alluvial flood plain were analyzed. Wetland sediments generally had higher levels of Hg than open water areas owing to a greater fraction of fine particles and higher levels of organic matter. Annual loading of Hg in open water areas was estimated at 4.3, 13.4, 19.2, 20.7, 129, and 135 ng cm(-2) yr(-1) for Beasley, Roundaway, Hampton, Washington, Wolf and Sky Lakes, respectively. Generally, the interval with the highest Hg flux was dated to the 1960s and 1970s.
authors.affiliation: College of Chemical Engineering, Zhejiang University of Technology, No. 18 Chaowang Road, Hangzhou, Zhejiang 310032, China.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Chemistry and Biochemistry, University of Mississippi, University, MS 38677, USA.
authors.forename: Pragya
authors.initials: P
authors.lastname: Chakravarty
authors.affiliation: Department of Geology and Geological Engineering, University of Mississippi, University, MS 38677, USA.
authors.forename: Gregg R
authors.initials: GR
authors.lastname: Davidson
authors.affiliation: National Sedimentation Laboratory, United States Department of Agriculture, Agricultural Research Service, Oxford, MS 38655, USA.
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Wren
authors.affiliation: National Sedimentation Laboratory, United States Department of Agriculture, Agricultural Research Service, Oxford, MS 38655, USA.
authors.forename: Martin A
authors.initials: MA
authors.lastname: Locke
authors.affiliation: College of Chemical Engineering, Zhejiang University of Technology, No. 18 Chaowang Road, Hangzhou, Zhejiang 310032, China. Electronic address: yingzhou@zjut.edu.cn.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Department of Chemistry and Biochemistry, University of Mississippi, University, MS 38677, USA.
authors.forename: Garry
authors.initials: G
authors.lastname: Brown
authors.affiliation: Department of Chemistry and Biochemistry, University of Mississippi, University, MS 38677, USA. Electronic address: cizdziel@olemiss.edu.
authors.forename: James V
authors.initials: JV
authors.lastname: Cizdziel
keywords: Mercury; Mississippi River; Oxbow lake; Sediment; Total organic carbon; Wetland