Fluorite in recent sediments as a trap of trace metal contaminants in an estuarine environment

The trace metal contamination of estuarine sediments of the Kishon river, running through a large industrial zone of Israel, was studied. The sediments were analysed for trace metal (copper, cadmium, iron, lead, mercury and zinc) contents, organic matter content, mineralogical composition and carbonate content. Significant intercorrelations between cadmium, copper, zinc, iron, carbonate content and fluorite (CaF 2) content were observed for Kishon river sediments. It was shown that the Kishon river estuary acts as an efficient trap for anthropogenic trace metals, propably through fluorite precipitation. The important processes for the movement of trace metals from the Kishon river to Haifa Bay appear to be the horizontal transport of contaminated fine grained particles along the river bottom, and transport of trace metals in soluble forms. The trace metal content in Kishon river sediments has considerably increased during the last 14 years.