Sediment trace metal contamination in the Ivory Coast, West Africa

A report outlines concentrations of iron, copper, mercury, manganese, nickel, lead and zinc found in sediments from the Ebrie lagoon on the Ivory Coast. The lagoon exchanged water with the Atlantic Ocean via the man-made Vridi Canal which was 300 m wide and 20 m deep. No trace metal studies had previously been carried out, although it was known that the BOD in the lagoon was 330 mg per litre where city wastewater was discharged, compared with only 1.8 mg per litre in the non-polluted forested areas of the lagoon. Excess loadings of especially mercury (2250 ng per g), lead (250 ug per g) and zinc (560 ug per g) were found and attributed to untreated sewage and industrial wastes being discharged to the lagoon.