Heavy-metal pollution in porirua harbour, New Zealand

Abstract

The <20 μm fractions of 72 sediment samples from Pauatahanui and Porirua Inlets of Porirua Harbour have been analysed for eight elements and the results compared between the two inlets. Co, Ni, Fe, and Mn occur in similar abundances in sediments from the two inlets and show no evidence of contamination. Cr concentration is somewhat higher in sediments from Pauatahanui Inlet and again shows no evidence of contamination. Cu concentration is significantly higher in sediments of Porirua Inlet and two samples taken in the vicinity of Porirua City are in the class uncontaminated to moderately contaminated. Pb and Zn show significantly higher concentrations in sediments from Porirua Inlet. Sediments in the vicinity of Porirua City attain the category moderately to strongly contaminated for Pb and moderately contaminated for Zn. No evidence of heavy-metal contamination is seen in sediments in the vicinity of State Highway 1. Heavy-metal pollution in Porirua Harbour therefore appears to be restricted to Pb, Zn, and, to a lesser extent, Cu, and occurs in Porirua Inlet in the vicinity of Porirua City. © Crown copyright 1990.