The presence of toxical, or ecotoxical xenobiotics is the basic criterion of the risk of ecosystem threatening. These materials may influence the quality of human environment significantly. The basic investigation of chemical materials penetrating into the environment either on purpose or by mistake (wastes) is not only exacting but also expensive. Methodology of toxicological and ecotoxicological investigations are at present (on the basic of different international agreements) on a such level that the results obtained may be accepted mutually and utilized in realization of counter measures. Chemical xenobiotics is important and it ought to be done not only by chemical or physical-chemical analysis but simultaneously also biologically. Biomonitoring on different level of toxicological testings more important because it brings concrete data of threatened working, and human environment and state of inhabitants´ health.