Assessing river water quality by means of multifactorial methods using macroinvertebrates. A comparative study of main water courses of Biscay

Abstract

Ninety two taxa of benthic macroinvertebrate were used to ordinate 175 sites from main water courses of Biscay (Basque Country) by means of correspondence analysis (CA). On the plane of the first two axes from CA, changes in macroinvertebrate community structure were observed between rivers due to differences in natural eutrophication and also as a result of the combined effect of industrial and urban sewage. The groups of taxa observed could be interpreted in ecological terms and were representative of headwater reaches, moderately eutrophic waters and polluted waters, respectively. This method of ordination provides more information on differences in water quality among the non-polluted sites than does a biotic index (BMWP score). © 1990.