Sediment analysis for the assessment of risk from organic pollutants in lakes

: The ability of decomposers to process variable amounts of xenobiotics in the marine sediment is a useful aggregate indicator of their capacity to prevent their accumulation and eventual ecotoxic effects. Since decomposition processes depend on environmental factors at the sediment which are difficult to mimic in laboratory systems, in situ evaluations in undisturbed sediments are of great interest. A method and its results are presented to evaluate the decomposition rates of PAHs (polynuclear aromatic hydrocarbons) in coastal undisturbed marine sediments at different levels of pollution input. The method is based on the application of pulse chromatography concepts to interpret trap and bed sediment monitoring data obtained at regular time intervals, using models of the water column as an anisotropic carrying medium. The results are for a 14 month data series from moderately polluted sediments near an urban site and at a more distant nearly pristine site on the south Atlantic coast. QSAR (quantitative structure activity relations) indicate that decay rates increase with higher UV absorption and lipidic solubility. At low levels of total PAH input to the sediments (<0.05 μg day(-1) g(-1)), decomposition mechanisms effectively process these compounds within a few days. At higher input levels (up to 0.12 μg day(-1) g(-1)), decomposition lags behind the inputs by approximately 25% and PAHs accumulate in the sediment. In situ estimates of the PAH input/decay ratios provide reliable ecosystem indicators of a safe threshold for anthropogenic inputs of PAHs to the marine environment and a basis for receptor-based standards aimed at their regulation.

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Congener profiles of polychlorinated biphenyls in core sediments of Sunderban mangrove wetland (N.E. India) and their ecotoxicological significance

Binelli

Sarkar

Chatterjee

et al. 2008

Environ Monit Assess

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The paper presents the first comprehensive survey of congener profiles of polychlorinated biphenyls (PCBs) in core sediment samples (<63 microm particle size) covering seven sites in Sunderban mangrove Wetland, north-eastern part of the Bay of Bengal. Results pointed out a non-homogenous contamination of the wetland with Sigma23PCB values ranging from 0.5 to 26.9 ng g(-1) dry weight, reflecting very low to moderate contamination closely in conformity to other Asian coastal environment. The general decreasing order of the dominant congeners to the total load was: CB138 > 153 > 149 > 101, indicating the predominance of hexa-chlorinated congeners. The spatial distribution revealed significant differences in concentration related to local urbanization with industrial and land-based sources. No uniform temporal trend on PCB levels was recorded probably due to particular hydrological characteristics of the wetland and/or non-homogenous inputs from point sources. Strong positive correlations between the seven dominant congeners suggest their common sources and similar environmental behaviors. These results were also used for a risk assessment evaluation in the Sunderban wetland, showing that the present PCB levels were exceeding in few cases the lower limit of sediment quality guidelines of Environmental Protection Agency and Canadian Council of Ministers of the Environment.

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Sediment analysis for the assessment of risk from organic pollutants in lakes

Cited by 9 publications

References 15 publications

Congener Profiles of Polychlorinated Biphenyls (PCBs) in Sediment Cores from Sundarban Wetland

Congener Profiles of Polychlorinated Biphenyls (PCBs) in Sediment Cores from Sundarban Wetland

Assessment of polynuclear aromatic hydrocarbons ecotoxicity threshold in marine sediments through in situ input/decay measurements

Congener profiles of polychlorinated biphenyls in core sediments of Sunderban mangrove wetland (N.E. India) and their ecotoxicological significance

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