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Title: Ecotoxocological impact of ferric sulphate on chironomid cultures and profundal reservoir communities
Author: N.P. Radford
Document Type: Monograph
Eutrophication has escalated in recent years, principally due to the use of fertilisers in modern farming methods and the discharge of sewage works effluent. The usual response to enhanced nutrient levels in lotic ecosystems is elevated phytoplankton growth which can lead to shading out of aquatic plants, oxygen depletion of hypolimnia and severe problems for the treatment of water for supply. It is generally recognised that long term control of eutrophication requires the limitation of nutrient supply. Phosphorus, rather than nitrogen, is deemed easier to limit and so most schemes for eutrophication control aim to reduce phosphate input from external sources or remove internal phosphorus loadings. The former are necessary as an initial step but recovery of the system can be delayed by recycling of phosphates previously accumulated. Sediments are of particular importance in this respect. Chemical treatment to remove available phosphates from the water column and or to prevent internal loading from the sediment is the basis of most schemes. Iron salts are most commonly used for this purpose. The study has concentrated on changes in chironomid community structure and on laboratory toxicity tests exposing Chironomus riparius to iron precipitates. The environmental impact of iron precipitate deposition is clear from this study but the potential impact of toxic impurities should also be investigated before the use of in reservoir ferric sulphate dosing is considered for other eutrophic reservoirs.
Publisher: National Rivers Authority
Publication Date: 1994
Publication Place: Peterborough
Subject Keywords: EutrophicationSulphatesIronToxicityWater reservoirs
Geographic Keywords: RutlandLeicestershire
Extent: 30
Total file downloads: 260

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