Determination of the Mercury Complexation Characteristics of Dissolved Organic Matter in Natural Waters with “Reducible Hg” Titrations

A new method for the determination of the concentration and conditional stability constant of dissolved organic matter that binds mercury (Hg) has been developed using an in vitro assay of reducible Hg. The technique is a wet chemical analogue to electrochemical approaches now in use for ligand stud...

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Bibliographic Details
Published in:Environmental science & technology 2003-08, Vol.37 (15), p.3316-3322
Main Authors: Lamborg, Carl H, Tseng, Chun-Mao, Fitzgerald, William F, Balcom, Prentiss H, Hammerschmidt, Chad R
Format: Article
Language:English
Subjects:
Applied sciences
Biological and physicochemical phenomena
Chelating Agents - chemistry
Dissolution
dissolved organic matter
Earth sciences
Earth, ocean, space
Edetic Acid - chemistry
Electrochemistry
Engineering and environment geology. Geothermics
Exact sciences and technology
Ions
Ligands
Mercury
Mercury - analysis
Mercury - chemistry
Models, Theoretical
Natural water pollution
Organic Chemicals
Pollution
Pollution, environment geology
Solubility
Titrimetry
Water Pollutants - analysis
Water pollution
Water treatment and pollution
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Summary:A new method for the determination of the concentration and conditional stability constant of dissolved organic matter that binds mercury (Hg) has been developed using an in vitro assay of reducible Hg. The technique is a wet chemical analogue to electrochemical approaches now in use for ligand studies of many other trace transition metals in natural waters. Ligand characteristics are obtained from additions of ionic Hg to buffered lake, river water, and seawater and determination of the wet chemically reducible fraction following equilibration of the spike. This approach is robust, as demonstrated by (i) analysis using three reducing agents of varying strengths, (ii) replicate analyses, (iii) comparison to well-characterized complexing species (chloride and EDTA) using a competitive ion-exchange resin, and (iv) kinetic studies. Results indicate that Hg-complexing equivalents are present in the dissolved phase (
ISSN:0013-936X
1520-5851
DOI:10.1021/es0264394