Screening and determination of mobility for mercury in marine sediment

Cavoura, Olga and Keenan, Helen and Davidson, Christine and Katsiris, Nicholas (2011) Screening and determination of mobility for mercury in marine sediment. In: 10th International Conference on Mercury as a Global Pollutant, 2011-07-24 - 2011-07-29. (Unpublished)

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Abstract

Implementation of a screening method for mercury in the marine environment for the identification of contaminated sediment followed by classification of mobility has been carried out in the Bay of Elefsis, one of the most industrialized areas in the Attica Region of Greece. With releases of mercury being both natural and anthropogenic, and sediment contamination resulting from surface water run off, discharge of industrial effluent, atmospheric deposition and from the aquatic environment itself, the extent of sediment mercury pollution is difficult to assess. Screening involving sample digestion, reduction of inorganic mercury to elemental mercury, and the trapping of elemental mercury on detecting papers with a copper iodide coating, to produce a colour the intensity of which is related to the mercury concentration in the sample has been implemented previously in soil and fresh water sediment [1]. This method was implemented in the marine environment. Marine sediment samples were obtained from the Gulf of Elefsis, both coastal and from the centre of the bay. Industrial discharges in the bay arise mainly from shipyards, steelworks and oil refineries. Coastal sampling points were selected in the region of two shipyards, two in the region of refineries, one from a ship disassembly unit, and one sampling point from an outlet that receives effluent from several industries such as asphalt and paper production. Three samples were also collected from the centre of the bay. Previous determinations of metal concentrations have indicated higher results for coastal regions, consistent with pollution directly as a result of main land industrial activity. Screening results indicate that total mercury concentrations in the majority of the samples exceed 0.1 mg/kg, the method detection limit. There is no agreed international limit value for mercury in sediment. However, subsequent quantification of the mercury concentration in the samples indicated that some exceed the Canadian sediment quality guideline value of 0.13 mg/kg for marine sediment. Determination of the mobility of mercury in the samples was carried out using sequential extraction, identifying mobile, semi mobile and non mobile species concentrations. The mobile fraction was further separated into organic and inorganic forms of mercury using solid phase extraction with sulphydryl cotton fibres [2].

ORCID iDs

Cavoura, Olga, Keenan, Helen ORCID logoORCID: https://orcid.org/0000-0003-0970-5392, Davidson, Christine ORCID logoORCID: https://orcid.org/0000-0002-8045-3530 and Katsiris, Nicholas;
CORE (COnnecting REpositories)