Trace metal levels in fish from the manukau harbour, auckland, new zealand, related to a water pollution incident (note)

Abstract

Concentrations of As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sn, and Zn in the heads, gut, and flesh of fish, and in oysters, which apparently died because of a pollution incident in Auckland's Manukau Harbour, were compared with concentrations in fish caught in the same area several days later. Most elements were present only at low levels; however, Cu in the gut of both sets of samples was 33–94 mg kg‐1 (fresh weight), Zn 35–104 mg kg‐1, Mn 12–83 mg kg‐1, and Ni up to 34 mg kg‐1. Oyster analyses were within normal ranges. Because of the small number of samples, detailed statistical analysis was not possible but results suggested that variations in metal levels between different parts of the fish and between species were greater than those between affected and control fish, making it unlikely that the fish were killed by a spillage of any of these metals. The cause of the deaths is now thought to have been oxygen deprivation. © Crown copyright 1988.