Bioaccumulation of heavy metals by aquatic macrophytes around Wrocław, Poland.

Studies were made of heavy metal accumulation in aquatic macrophytes growing in streams and ponds around Wroclaw, Poland, partly affected by atmospheric pollution, effluents of chemical factories, and groundwater contaminated by slagdumps from a smelter and power station. The highest concentrations of Cd, Co, Cr, Cu, Hg, Ni, Pb, and Zn in surface water and aquatic macrophytes surpass the average values established for background reference sites. Significant positive correlations were found between Cu contents in water and Cu, Cd, and Zn contents in plants, between Cu and Cd in plants, between Co and Ni in plants, between Ni contents in water and Ni and Cu contents in plants, between Zn in water and Cu in plants, and between Cd and Ni in plants. Negative correlations were found between Cd contents in water and Zn contents in plants, between Co in water and Cd in plants, and between Zn in water and Co in plants. Experiments with the liverwort Scapania undulata originating from a clean, forested, mountain stream and cultivated in solutions containing 70-100% sewage from a chemical factory demonstrated an increase in lead content (85 times in 100% sewage and 58 times in 70% sewage) and in mercury content (40 times in 100% sewage and 20 times in 70% sewage), and also an increase in contents of Cd, Cr, Cu, and Ni. Exposure to 70% sewage concentration during the 14 days of the experiment may be recognized as harmless for S. undulata, so this liverwort could be used in biotechnical purification of water.