TRACE-METALS IN SEDIMENTS AT THE LOWER REACHES OF MEDITERRANEAN COASTAL RIVERS, ISRAEL

Concentrations of mercury, lead, copper, zinc, cadmium, iron acid part ially chromium, manganese, nickel and aluminium, were recorded in surf ace sediments al the lower reaches of 11 rivers from the Mediterranean coastal zone of Israel, during 1988-1993. Excluding the lower Kishon river, no major contamination was found at most of the stations when t race metal concentrations were normalized against iron concentrations (trace metal/iron ratios) and compared to levels recorded in stream se diments from the southern drainage basin of the Kishon river. Minor en richments found in part of the rivers are attributed to land-based poi nt sources of pollution. Variations in trace metal concentrations at t he estuaries are related to high influx of fine-grained sediments tran sported by heavy floods during rainy winters, which later are resuspen ded and transported seaward by bottom currents.