Pentachlorophenol (PCP), PCDD,PCDF and pesticide concentrations in a freshwater lake catchment

The concentrations of pentachlorophenol (PCP), polychlorinated dibenzo-p-dioxins (PCDDs) polychlorinated dibensofurans (PCDFs) and organochlorine and organophosphorus pesticides in water, sediments and biota from the Lake Rotorua catchment were determined to evaluate the relative significance of various contaminants and their potential sources. PCP was found in water, sediments and biota (fish and freshwater mussels) and the highest concentrations in water (3.62 μ g.L⁻¹) and in sediments (400 ng.g⁻¹ dry weight (DW) were found in and near a stream that had been affected by PCP contamination from a sawmill. PCDD and PCDF concentrations in all cases, except for the waters and sediments of the stream near to the sawmill, were relatively low compared to values reported in the literature for similar sites. Negligible pesticide contamination was found in the Lake Rotorua catchment. Pesticides found included low concentrations of p.p′-DDE, p.p-TDE and dieldrin in rainbow trout from the lake.