Water toxicity of the Don River mouth area by bioassay battery data
At present, toxicity is one of the most important characteristics of surface water quality. The Don River mouth area is characterized by the change in surface water quality due to influence of the dissolved substances of anthropogenic and natural origin, incoming with the waters of the Lower Don River tributaries and diffused runoff from the water catchment basin. The research is aimed to assess water toxicity in the Don River mouth area from Aksay to Azov in the summer months by means of a bioassay battery. Water samples were collected using a vessel at the Roshydromet (Federal Service for Hydrometeorology and Environmental Monitoring of Russia) section line. Bioassay was carried out in accordance with the Federal Environmental Instruments of Russia and Roshydromet Regulations. Autotrophic (microalgae Chlorella vulgaris, Tetradesmus obliquus, higher plant Raphanus sativus) and heterotrophic (Daphnia magna) test organisms were used. The number of toxic samples in July and August was almost the same. For both months, the areas, where water toxicity was detected, coincided with the places of water intake and sewage discharge of Rostov-on-Don city. Water samples, taken below the second discharge outlet of Rostov-on-Don, were most toxic and retained their inhibiting effect even after dilution. In July, toxicity was also detected above the confluence of the Aksay River branch with the Don River and below the discharge outlet of the city of Azov. In August, the effect of undiluted water samples changed to the inverse and became stimulating, as opposed to the July bioassay data. An increase in the inhibiting but non-toxic effect of water downstream and with depth was noted. Deep water layers were characterized by acute toxic effects. The water at individual sampling sites had diverse (inhibiting or stimulating) effects on different test subjects. By optical density endpoint, the most sensitive test subject was Chlorella vulgaris; by mortality endpoint, the least sensitive ones were Daphnia magna crustaceans. The study of water toxicity in the mouth area of the Don River is necessary to carry out using bioassay battery with endpoints more sensitive than mortality. Water toxicity at the mouth area of the Don River in 2016 decreased compared with the water toxicity data based on bioassay from the previous twenty-year period.
| Main Authors: | , , , |
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| Other Authors: | |
| Format: | Journal Contribution biblioteca |
| Language: | Russian |
| Published: |
2019
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| Subjects: | Toxicity, Surface layers, Bioassay, Chlorella vulgaris, Water sampling, Tetradesmus obliquus, Raphanus sativus, Test objects, Anthropogenic effects, Токсичность, Пробы воды, Водосбор, Стимулирующее действие, Тест-показатели, |
| Online Access: | http://hdl.handle.net/1834/15953 |
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