Dissolved copper, lead and cadmium in Pingtan waters, East China Sea

Abstract

Dissolved Cu, Pb and Cd contents in the surface and bottom water samples collected from 36 stations in Pingtan waters (in Fujian Prov.), East China Sea, during two survey cruises in May and Oct. 1990 were determined for the first time by solvent extraction and atomic absorption spectrometry. Their content ranges (the mean values) in May were 0.32–2.02(0.81), 0.007–0.880(0.235) and 0.008–0.052(0.023) mg·m⁻³, respectively; those in Oct. were 0.52–1.79(0.88), 0.007–0.800(0.301) and 0.021–0.060(0.035) mg·m⁻³. The metals in May and Oct. had markedly different areal distributions characteristics mainly caused by mixing of various water systems. There were positive relationships between dissolved Cd and inorganic N in May, and between dissolved Cd and soluble phosphate in Oct. The obtained molar ratios, ΔCd:ΔN=1.1×10⁻⁵ and ΔCd:ΔP=5.8×10⁻⁴, were close to those in plankton reported, showing dissolved Cd’s biogeochemical behaviour and process.