1970’s: Cockburn Sound – Owen Anchorage. Pesticides detected: Dieldrin, Dichlorvos

Pesticide Residue Level in Cockburn Sound (Chegwidden 1979)

A number of specific studies were carried out in the mid 1970’s, leading to the production of the Cockburn Sound Environmental Study, 1976-1979 published by the then Department of Conservation and Environment (Report No 2). One of these studies investigated the presence of pesticide residues in water, sediment and mussels of several localities in Cockburn Sound.

Levels of total organochlorine insecticides found in sediments and mussels of Cockburn Sound were less than 0.001 ug/kg. Sediments from one sampling station in Owen Anchorage contained 4 ug/kg of dieldrin while the effluent from Anchorage Butchers contained 15 ug/kg of dichlorvos insecticide. No pesticide residues (in fact, no chlorinated hydrocarbons of any sort) were found in samples of the common mussel Mytilus edulis taken from the Sound. The study concluded that the extent of pesticide contamination could not be inferred from one sample, and recommended that “a survey be taken to quantify the extent of sediment and biota contamination by pesticides, particularly in Owen Anchorage”.

P42 Monitoring Pesticides – A Review. A Report to the Environmental Protection Authority by Peter A Rutherford. December 1989