Human activity causes a serious increase in the variability and concentrations of chemical compounds present in bottom sediments and sorptive properties of sediments, and intensifies the deposition of hard-todecompose and toxic substances, including heavy metals, radionuclides, and hydrophobic organic compounds. Those substances may cause elimination of ecologically important groups of benthic organisms, and disrupt the function of the water ecosystem.
A significant development of methods of ecotoxicological studies in aqueous environments has been seen during the last two decades. Monitoring concentrations of selected metals and organic compounds has been supplemented by bioindicative methods. Routine use of batteries of ecotoxicological tests allows for complex hazard and risk assessment of sediment pollution. According to the law, it is necessary to evaluate the toxic effects of newly developed and existing compounds on bottom biocenoses. The presented study describes problems of ecotoxicological sediment quality assessment and toxic substances, and is mainly focused on selecting proper test methods and a clear and compact classification of sediments.