BHC residues of domestic origin: A significant factor in pollution of freshwater in Northern Ireland

Abstract

The concentration of BHC residues in the water of rivers discharging into Lough Neagh shows a high correlation with urban population density in the catchment area of the rivers. Investigations demonstrate that this correlation arises as a result of the discharge of sewage effluents containing BHC into the watercourses. BHC in such effluent appears to have a domestic—rather than an agricultural or industrial—origin, probably arising from the use of wood preservatives in the home. Studies on the effect of various concentrations of BHC on species of mayfly larvae indicate major reductions in survival time at γ-BHC levels as low as 100 ng. 1 −1. Thus, even the relatively low concentrations of BHC observed in Northern Ireland river waters—and indeed in surface waters throughout the United Kingdom—may well pose a threat to aquatic ecosystems, particularly in the vicinity of sewage outfalls.