Benthic diatoms in polluted river sections of Central Poland

Water quality was investigated in the most polluted sections of three rivers in Central Poland: the Rawka, Jeziorka and Bzura. The estimate was carried out using the Lange-Bertalot indicatory method, which is based on various diatom tolerances to pollution, and by calculating the saprobity index of Pantle & Buck. In the investigated rivers, Cocconeis pediculus, C. placentula, Fragilaria construens, F. pinnata, Gomphonema olivaceum, Melosira varians, Meridion circulare, Navicula lanceolata were the most frequent dominants of species sensitive to pollution. The most frequent tolerant species were Achnanthese lanceolata ssp. frequentissima, Cymbella silesiaca, Fragilaria capucina var. vaucheriae, F. ulna, Navicula capitata var. capitata, N. gregaria, N. pupula, and Nitzschia amphibia. The dominants of the resistant group were Gomphonema parvulum, Navicula saprophila, N. veneta, and Nitzschia palea. On the basis of the methods mentioned above, the water of the Rawka River was assigned to water quality class II/II-III, that of the Jeziorka to class II-III/III and that of the Bzura (at both study sites) to class II-III.