Trace metal fronts in Scottish coastal waters

Abstract

Dissolved cadmium and copper concentrations have been determined in 76 surface water samples in coastal and ocean waters around Scotland by anodic stripping voltammetry (ASV). A trace metal/salinity ‘front’ is observed to the west, north and north-east of Scotland separating high salinity ocean water (>35 × 10 −3) with low concentrations of dissolved Cd and Cu from lower salinity (<35 × 10 −3) coastal water containing higher concentrations of Cd and Cu. Mean Cd concentrations in ocean and coastal waters are 7 ng dm −3 (0·06 n m) and 11 ng dm −3 (0·10 n m) respectively; for Cu the respective levels are 60 ng dm −3 (0·95 n m) and 170 ng dm −3 (2·68 n m). The observed distribution is attributed principally to freshwater runoff and the advection of contaminated Irish Sea water into the study area.