Afiliere: Universitatea de Vest “Vasile Goldiş” din Arad, Facultatea de Biologie
ANTROPIC POLLUTION INFLUENCE ON AQUATIC ECOSYSTEMS IN MAIN HIDROGRAPHIC POOLS FROM WESTERN ROMANIA. Four sites along the downstream part of River Mureş, Romania, were investigated by limnochemistry and community analysis (microorganisms, plankton, macrozoobenthos) in order to monitor pollution. Although larger pollutant-releasing accidents have decreased in frequency during the last decade, high concentrations of cadmium (up to 8.7 mg/kg) and copper (up to 49.2 mg/kg) were found in the sediment, predominantly at the most upstream sites likely being due to the mining and metallurgical activities along tributaries of the Mureş. In addition, at the same sites, high counts of faecal coliforms and streptococci (up to 1300 and 490 counts per 100 ml, respectively) indicated contamination by untreated sewage. Conventional limnochemistry on nitrogen and phosphorous compounds, oxygen concentration, pH, as well as chemical analysis on PAHs and PCBs did not reveal any exceptional data. Despite the presence of metal and faecal contamination, the number of species, numerical density and biomass of macrozoobenthos, phytoplankton and zooplankton communities did not differ considerably among the sites and, therefore, failed to indicate pollution. However, an exceptional situation for the most polluted site was revealed by a ~20% reduced diversity and evenness of the phytoplankton, and 30 to 70% increased Bray-Curtis indices of distance to the planktonic communities at the other sites.