Evaluation of the genotoxic potential of surface water of anthropogenically loaded areas using eukaryotic test objects (on the Zubra River example, Lviv, Ukraine)

Background. Rivers are important water objects in many cities in Ukraine and around the world, and their hydroecological state causes concern. One of them is the Zubra River (Lviv, Ukraine), a right tributary of the Dniester which is subject to long-term anthropogenic load from sewage and household waste, and its hydroecological state is assessed as unsatisfactory (Ivanov et al., 2023). The aim of the study was to evaluate the genotoxic potential of surface water in anthropogenically loaded areas on the example the Zubra River using Allium cepa and Drosophila melanogaster as eukaryotic test objects. Materials and Methods. Surface water samples of the Zubra River were taken in different seasons of 2023 and their chemical composition was analyzed by standard methods. The impact of the water samples on the survival of Drosophila melanogaster laboratory strain Oregon R was assessed using the larval feeding method, while their genotoxic potential was evaluated through the dominant lethal mutation test. The phyto- and cytotoxicity of water samples were assessed using the Allium cepa test based on the growth and mitotic activity of onion roots of the Stuttgarter Riesen variety. The genotoxic potential was determined using the ana-telophase method by analyzing the frequency of chromosomal aberrations. Results and Discussions. The chemical analysis revealed an increased concentrations of ammonium, nitrite and phosphate ions in surface water samples from the Zubra River indicating its Vth quality class (very poor) and an unsatisfactory hydro-ecological state. Treatment of D. melanogaster with river water samples reduced their survival rate by up to 77.66–78.97 % compared to the control, and significantly increased the frequency of the dominant lethal mutations by 1.54–3.44 times. Water samples significantly decreased the growth and mitotic activity of the Allium cepa roots as test objects, however no genotoxic effect was detected: the frequency of chromosomal mutations in the apical meristem was not statistically different from the control. Conclusion. For an objective assessment of the genotoxic potential of surface water of rivers in anthropogenically loaded areas, it is recommended to apply plant and animal objects that differ in their test reactions. The study based on the example of the Zubra River showed that surface water samples with an elevated concentrations of ammonium ions, nitrites and phosphates do not cause a genotoxic effect in A. cepa as a plant object but show a weak genotoxic potential in D. melanogaster by inducing a significant increase in the frequency of dominant lethal mutations and a decrease in individual survival rates.