The Environmental Impact of a Chemical Spill from a Timber‐Treatment Works on a Lowland River System

A major timber‐preservative spillage, resulting from a fire at a timber yard, released substantial quantities of tributyltin and lindane (g hexachlorocyclohexane) into the River Bourne ‐ a tributary of the River Thames. This paper describes the chemical and biological effects resulting from the incident. Water‐column concentrations in the River Bourne South ranged from below detection limits to 5200 μg/l and 3700 μg/l for tributyltin and lindane respectively, with contamination extending 80 km into the Thames estuary. The high concentration of pollutants caused extensive fish mortality and virtually eradicated the invertebrate population in the immediate vicinity of the spill. Although sediment monitoring revealed initially high surficial sediment concentrations of tributyltin (3300 ng/g) and lindane (490 ng/g), loadings declined over a period of time, but it is perceived that contaminated sediments may pose a longer‐term threat to benthic communities, particularly in the proximity of the spill site.