Mercury Contamination in the Seine Estuary, France: An Overview

摘要

As mercury in the Seine estuary is mainly associated with suspended particulate matter (> 90%), its dynamics is governed by sediment erosion-deposition cycles which are strongly developed in this macrotidal estuary. However, it can be mobilized by two reactions, methylation and reduction. The former favors bioaccumulation through the production of methylmercury, and the latter is conducive to atmospheric recycling through the formation of volatile elemental mercury. Freshwater inputs into the Seine estuary reflect anthropogenic influences; the average concentrations for the last five years are 2.9 +- 2.1 ng L~(-1) for the dissolved and 1.7 +- 0.7 μg g~(-1) for the particulate phase. Contamination of sediments is especially high in the upper estuary (> 1 μg g~(-1)), but decreases downstream (down to 0.2 μg g~(-1)). Yet the levels measured in animals are rarely higher than in the European guideline for human consumption. Temporal trends have shown a general decrease in concentrations.