Application of factor analysis in the assessment of toxicity formation in sediments ofrivers of Rivne oblast
National University of Water Management and Nature Resources Use
11, Soborna St., Rivne 33028, Ukraine
The author revealed that it is the substances of peat, saprobic and toxicological units lead to the worst category of surface waterquality of the rivers in Rivne Oblast. Those substances are able to accumulate in sediments. The researcher analysed the samples of undisturbed sediments and their water extracts which were taken from the rivers with different anthropogenic load during the autumn-winter and spring-summer low waters by bioassay in chronic experiments. The author also considered the test reactions of indicator organisms of different systematic groups in order to assess the toxicity index of sediments between 7.6 and 72.6% at the same time, the research rated toxicity from I (“excellent” condition) to V (“extremely bad”). The research also evaluated variability of toxicity indicators that indicated chronic toxicity of sediments in the rivers with high anthropogenic load. Nevertheless, the water extracts had higher toxicity levels in autumn-winter period, while the undisturbed sediments showed greater toxicity indicators in spring-summer period. This results in the necessity of their separate analysis during the toxicology assessment of hydro-ecosystem. The author discovered the direct correlation connection of sediments’ toxicity with such hydro-chemical parameters as dissolved oxygen (correlation and determination coefficients are 0.62 and 0.39 accordingly) and chlorides (0.62 and 0.39). The research also determined the inverse relationship with the content of iron (-0.54 and 0.29) and manganese (-0.67 and 0,45).
Keywords: hydro-ecosystem, toxicity, test objects, factor analysis