The influence of inputs to the Firth of Forth on the concentrations of trace metals in coastal waters

The distribution of copper, lead and cadmium in dissolved and particulate phases has been investigated in the Firth of Forth, Scotland, an embayment of the North Sea. The effect of riverine and anthropogenic trace metal inputs on concentrations in the Firth of Forth and adjacent North Sea is examined. For the dissolved phase the effect of such inputs is confined to the immediate area of discharge. Concentrations in the outer Firth are indistinguishable from those in coastal waters of the North Sea, ca. Cu, 0·2 μgdm −3 ( 3·1 n m ); Pb, 0·025 μgdm −3 ( 0·12 n m ) and Cd, 0·020 μgdm −3 ( 0·18 n m ). There is evidence that particulates enhanced in trace metals, relative to bottom sediments, are leaving the Forth and entering the North Sea. Predictions of the total metal concentrations in the waters of the inner Firth, based on riverine, industrial and sewage associated inputs, show reasonable agreement with observed values.