HEAVY-METALS IN RIVER TEES ESTUARY SEDIMENTS

A detailed survey of the River Tees estuary in the north east of England has been carried out to determine the levels of total heavy metal concentrations in its bed sediments. Samples were collected at 31 locations, 0.5 km apart between the upper dredging limit and the river mouth. Three samples of the surface sediments were taken at each location; from the north and south banks and at mid-channel. The mean total metal concentrations after acid digestion were found to decrease in the order Zn > Mn, Pb > Cu > Cr > Ni > Cd for the sample locations. Along some locations of the estuary, the maximum and other peak metal concentrations were similar to those found in strongly polluted industrialised rivers.