Chemical Changes in the Sediments of Loch Eil Arising from the Input of Cellulose Fibre

Studies of the effect of a particulate cellulose effluent from a pulp and paper mill on the sediments of Loch Eil have shown that redox measurements taken at a series of stations can be used to map those areas of sediment exhibiting high reducing activity. The extent and variations in these areas is closely related to the input levels of waste cellulose fibre and provides a useful indicator of the ‘health’ of the sediment. Some of the changes in sediment chemistry resulting from increased input of fibre give rise to an increase in sediment sulphide levels. Changes also occur in the nature and amount of the low molecular weight acids formed in the sediment during cellulose degradation. In the area of highest deposition both acetate and succinate are found, but the highest levels of acetate are present in areas of intermediate deposition. The measurements made on the above parameters are discussed in relation to their use in assessing the short term changes in sediments subject to variable inputs of organic pollutants.