The Use of Biomarkers in the Toxicological Risk Assessment

Abstract

The risk assessment procedure made either for protection of ecosystem or human health is normally based on standardized toxicological test methods. Most of these tests are expensive and require in vivo animal experiments. On the other side, it is important to detect low concentrations of toxic substances in various mixtures that are present together with other non-toxic compounds, as early, as possible. For this early warning the traditional methods in toxicology cannot supply an adequate basis. Recently, some relatively inexpensive and simple methods suitable for classification of dangerous wastes and pollution of surface water have been developed. The practical implementation of such methods would have of high significance in the assessment of the state of surface waters (rivers and lakes), as well, as industrial effluents. In order to compare the performance of the various bioassays a series of examinations have been carried out with various methods. Microbio-test kits seem to be especially useful for the water quality assessment of rivers and lakes. Data are given on the monitoring of some important habitats in Hungary. The toxicity estimation with different bioindicators discussed in the presentation can give us a habitat-specific indication of the pollution. The results revealed that the alternative tests are sensitive to indicate the combined effect of various pollutants in aquatic ecosystems. It seems to be that the tests using crustacean species would give realistic results in well-defined point sources, but they can be accepted somewhat more sceptic when comparing samples taken form different habitats. Daphnia heart rate were specific for a number of compounds. Presently the luminescent bacterial systems are extensively used as standardized bioassays in the environmental impact assessment. An important conclusion of the results that there is no universal bioassay available for detection of all types of pollution. The best results can be obtained with employment of a battery of bioassays.