Formulation of the problem. Regulation of hazardous chemicals admission to surface water is carried out by means of appropriate water quality standards. Researching the systems of surface water quality regulation in different countries, it has been determined that there is a tendency to use standards for the protection of the aquatic ecosystem and for meeting the needs of society and industries - environmental quality standards. Such standards are based on obtaining ecotoxicological information of a dangerous chemical substance on the representatives of the aquatic ecosystem. Among them, some of the most sensitive test organisms are crustaceans from the Daphniidae family. They are used to establish water quality standards for chemicals, to assess the quality of wastewater and surface water using a toxicological indicator. It is recommended to use a standardized international methodology to assess effects of chemicals on Daphnia magna Straus (OECD No. 202) to establish environmental water quality standards in EU countries. However, in Ukraine, in water protection practice, the most popular test organism is Ceriodaphnia affinis Lilljeborg (Daphnia sp.).
The purpose of the article. In order to set ecological standards for water quality of chemicals in Ukraine, the authors proposed to test the OECD No. 202 methodology using Ceriodaphnia affinis test organisms and to establish metrological characteristics for it.
Presentation of the main research material. The authors tested the OECD methodology No. 202 [21] on the crustacean culture Ceriodaphnia affinis from the culture collection of the Laboratory of Ecological and Toxicological Research, the V. N. Karazin KhNU. The coefficient of variation of EC50-24 and EC50-48 K2Cr2O7 was 16,8 % and 15,9 % respectively. Based on the data obtained, the metrological characteristics of the tested method were established: the response range of the test organisms Ceriodaphnia affinis is the following – 1,45<EC50-24 <2,91 (mg/dm3); reproducibility of the results of determining the toxicity of a chemical substance – 0,18 mg/dm3 (16,1%); the error in the results of determining the toxicity of a chemical substance – 0,34 mg/dm3 (31.6 %); standard of operational control – 0,49 mg/dm3.
Scientific novelty and practical significance. The findings confirm the possibility of using Ceriodaphnia affinis in a short-term test in setting environmental water quality standards in Ukraine.
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