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 timbe r 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 resul ting from the incident. Water-column concentrations in the River Bourn e South ranged from below detection limits to 5200 mu g/l and 3700 mu g/l for tributyltin and lindane respectively, with contamination exten ding 80 km into the Thames estuary. The high concentration of pollutan ts caused extensive fish mortality and virtually eradicted the inverte brate population in the immediate vicinity of the spill. Although sedi ment monitoring revealed initially high surficial sediment concentrati ons of tributyltin (3300 ng/g) and lindane (490 ng/g), loadings declin ed over a period 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.