Organochlorine pesticides and hexachlorobenzene along the central coast of New South Wales: multi-scale distributions using the territorial damselfish Parma microlepis as an indicator

Concentrations of 10 organochlorine pesticides and hexachlorobenzene (HCB) were determined in the territorial damselfish Parma microlepis at three urban locations and three reference locations centred on the Sydney region. Dieldrin, HCB and DDE were the most frequently detected organochlorines, occurring in 70–100% of samples collected. Alpha and gamma chlordane were also reasonably common and occurred in more than 30% of the samples. Each organochlorine compound investigated had a distinct spatial pattern of distribution. Related chemicals such as alpha and gamma chlordane, and DDT, DDE and DDD tended to have similar patterns of distribution. There were clear differences in patterns of distribution in organochlorines between urban and reference locations shown using non-parametric multivariate techniques. Relative variability of samples from urban locations was higher than at reference locations in 1993, but there was no consistent pattern of differences in the dispersions of samples among urban and reference locations in 1994. Age and condition indices (K) showed no association with total concentrations of organochlorine residues in fish. Significant, but weak associations were found between organochlorine residues and size, gonad somatic and liver somatic indices.