New assessment of organic mercury formation of highly polluted sediments in the Lenga estuary, Chile

YAÑEZ, J.; GUAJARDO, M.; MIRANDA, C.; SOTO, C.; MANSILLA, H.; RUSSELL, A.
Marine Pollution Bulletin 73:1 (2013) 16-23.

DOI: 10.1016/j.marpolbul.2013.06.015

Abstract

Anomalously high levels of mercury in sediment in the Lenga estuary, Chile are comparable to the mostcontaminated sites previously reported elsewhere. Total mercury (Hgtotal) concentrations range from 0.5to 129 mg kg-1 and organic mercury (Hgorg) from 11 to 53 μg kg-1. The highest levels are in areas nearthe previous wastewater outfall of a chlo-alkali plant. The results show that the proportion of Hgorg/Hgtotal in the sediment varies by more than two orders of magnitude (0.02–5.7%) according to the concen-tration of Hgtotal. No correlation between the concentration of Hgorg and Hgtotal was found. The lack of cor-relation does contrast with the findings of other authors in culture media. Our results indicate that evenat very high concentrations of Hgtotal and organic matter do not influence organic mercury formation inestuary sediments. The disparity in Hgtotal and Hgorg concentrations also attests to environmental differ-ences in the formation.

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