Pollution in the river team and invetigations of zinc toxicity to elected algal species

Abstract

The River Team is a 26.8 km tributary of the River Tyne; it enters the Tyne at Newcastle. Aspects of pollution were studied in the River Team over a five month period from April to August 1979. Sources of pollution included sewage effluents, mining and industrial discharges. Nine sampling sites were chosen above and below various sources of input in order to obtain a representative profile of the river. Water and sediment samples were collected for analysis from the nine sites throughout the five month period. Particular attention was given to zinc as this was one of the pollutants in the river. Levels up to 28.60 mg 1(^-1) total Zn were recorded below one industrial drain which discharges effluent from Durham Chemicals. This firm produces a variety of zinc-based products which are used by other industries. A Survey was conducted below the major sources of mining and industrial input to determine the discharge variations occurring throughout a 24 h period. Organisms found at the nine sites were identified. Laboratory experiments were conducted to determine the toxicity of various zinc concentrations on selected species of algae collected at the sites. Experiments conducted on Stigeoclonium tenue Kutz, revealed that zinc-sensitive strains occurred in the upper stretch of the river which was relatively uncontaminated in comparison with the highly polluted lower stretch where zinc-tolerant strains of S.tenue survived. A species of Ulothrix collected from the mouth showed relatively poor resistance to zinc. This result was very unusual as the tolerance index concentration (T.I.C.) was much lower than the field concentration of zinc at this site. Various explanations are suggested to account for this unusual phenomenon.