Impact of heavy metals on benthic oligochaete communities in the river Ill and its tributaries
Impact des métaux lourds sur les communautés benthiques d'oligochètes dans l'Ill et ses affluents
Résumé
The influence of heavy metals in sediments on oligochaetes was investigated at 15 sites in the Ill river, France, and its tributaries. Metals, TOC and Kjeldahl nitrogen were analysed in sediments passing a 0.02 mm sieve. Metal concentrations were expressed as ratios to natural background values. Benthic oligochaetes were collected by net or corer, examined microscopically and determined to species level : 51 taxa were identified. The data were evaluated by principal component analysis. Some sediments at sites subject to industrial influence were high in mercury, copper, chromium, lead and zinc. Five oligachaete species which were either pollution-tolerant or opportunist dominated the communities. Tubificidae without hair setae were positively related to heavy metal sediment contents ; Tubificidae with hair setae were negatively related.
Le but de l'analyse de l'étude est de décrire l'impact de la pollution des sédiments par des métaux lourds sur les communautés d'oligochètes. Des analyses ont été effectuées sur des sédiments, prélevés sur l'Ill (Bassin du Rhin).