Résumé :
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The continuous increase in the amounts of treated and untreated industrial and municipal effluents discharged into rivers, especially in the densely populated and highly industrialized parts of Europe, has led to a corresponding increase of micropolluants on river sediments. The Working Group concentrated on the three metals, cadmium, lead and mercury, and on polycyclic aromatic hydrocarbons. Significant human exposure to these micropollutants can results as a consequence of their concentration on sediments. Such exposure mmay occur via agricultural products contaminated with micropullutants as a consequence of irrigation or the application to land of sediments from dredging or flooding by rivers. In view of its mobility in soil, its uptake by plants, its toxicity and its long half-time in man, cadmium poses the greatest risk. Serious problems arise from the contamination of the aquatic environment. Fish accumulate micropollutants such as arsenic and mercury, while in the estuarine environment it is well know that filter-feeders have an outstanding ability to accumulate heavy metals. Measurements of metals and PAH in sediments is an important monitoring tool in assessing the degree of pollution of the aquatic environment and the temporal and spatial trends. CAre must be taken to ensure that the data are comparable with respect to the effect of sediment particle size. Altough analytical methods are available for the measurement of total metals and PAH, there are serious deficiences with respect to knowledge needed in connection with determinations of biological availability and partitionning.
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