Biotesting of Surface Waters of the Vorskla River Using Three Test Organisms as Indicators

Abstract

Introduction. In accordance with the Water Framework Directive 2000/60/EC of the European Parliament and of the Council establishing a framework for Community action in the field of water policy, standards for monitoring, surveying, sampling, and laboratory analysis of water bodies have been developed.
Problem Statement. In Ukraine, a significant problem has remained the insufficient development of protection technologies and control methods capable of predicting the ecological state of water bodies based on toxicological parameters. Conventional approaches have not fully ensured reliable assessment of the integrated toxic effects of pollutants. The application of biotesting has enabled determination of wastewater impacts using biological responses, thereby providing conclusions regarding the toxicological state of aquatic ecosystems.
Purpose. This study has aimed to assess the quality of surface waters using biotesting methods and to determine the impact of wastewater on aquatic biocenoses involved in self-purification processes, based on toxicological parameters.
Materials and Methods. The Bioindication Water Test method has been applied, involving staged laboratory tests using a laboratory culture of Daphnia and natural populations of the rotifer Rotaria rotatoria as test organisms collected from the studied water bodies. Laboratory, microscopic, biotesting, and statistical methods have been employed.
Results. Biotesting on crustaceans has demonstrated that water from the Vorskla River has exerted an acute toxic effect on Daphnia and Rotaria rotatoria. A 50% decrease in the survival rate has been recorded over 96 hours of exposure, indicating that water quality has not met established standards for toxicological indicators. Toxicological analysis of surface waters has shown that the highest toxicity has been observed in samples collected from the sewage discharge zone near the Poltava stormwater collector.
Conclusions. Biotesting as an integral method for assessing aquatic toxicity has been shown to be a necessary
complement to physicochemical analysis. It has provided direct evidence of organismal responses to pollution and has enabled effective control of wastewater discharges that contribute to ecosystem degradation. The implementation of biotesting has supported compliance with the requirements of Water Framework Directive 2000/60/EC aimed at improving the ecological status of water bodies in Ukraine.