Changes in water quality and macrozoobenthos in the River Elbe since 1989
Guhr, H.; Dreyer, U.; Spott, D.
German unification caused a structural change in industry and land use. Many obsolete factories without wastewater purification systems were closed, the number of livestock in agriculture was reduced and new sewage treatment plants were and are being built. The impact of these changes on water quality and the biocoenosis is tremendous. Organic pollution of the River Elbe decreased by more than 50%, and now the oxygen content is always more than 4 mg/l. Total phosphorous content decreased by 60%, but the concentration of inorganic nitrogen remains at about the same level as in 1989. Due to improved transparency, intensive growth of algae can be observed in summer. Many species of the macrozoobenthos have recolonized the substratum. This tendency is further enhanced by the still-existing great structural variety of the Elbe, which is worth protecting.