The Chemical Composition of the River Aire and Anthropogenic Impacts on the River from its Source to Leeds.

Abstract

Water samples were collected from the Aire River (flowed from its source at Malham towards Leeds)  and its tributaries (Earby Beck, Glusburn, and Eller Beck), in the summer of 2013.  Chemical analysis was carried out on the samples to assess the natural and anthropogenic control and impact on the river’s composition. The major cations were analysed by ICP-AES and anions by IC and HCl titration. The chemistry of the water for all samples were dominated by calcium and bicarbonate. The results indicated that calcium ions accounted for 89% of the total cation charge budget of the Aire at its source at Malham, but decreased whilst the contribution  of  sodium, potassium and magnesium ions to the cation budget increased as the flow of the river approached  Leeds from source . Sodium ion recorded the highest cation concentration of 61 mgL^-1 at Calverly Lane Bridge and 39% contribution to the  cation charge budget. The anions were dominated by alkalinity for all the samples, however alkalinity decreased in anion charge budget component  of 92% from Malham to 37% at Calverly Lane Bridge. The anion budget had increased percentages for chloride, nitrates and sulphate ions as the river approached Leeds. Contributing to 34%, 7% and 22% respectively to the anion budget. The increased concentrations of sodium, potassium, chloride, nitrate and sulphate changed the chemical composition of the river considerably. The reason for the chemical change was attributed to the effects of heavy point source discharges of communal sewage, industrial effluent and agricultural fertilizers input on the improved grasslands of the catchment into the river. The conclusion was that, anthropogenic activity has a considerable effect on the River Aire as it flowed through the urban areas of Bradford and   Leeds.

Keywords: Concentration, charge budget, anthropogenic, effluent, fertilisers, point source discharge, River Aire