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UDC 574.632/635

Chesnokova S. M., Savel'ev O. V.

Study of the antibiotics effect on self-purification processes
of hydroecosystems

Summary

Based on literature data the role of hydrobionts of various ecologic groups in self-purification processes of aquatic ecosystems is considered alongside with the possible effect of antibiotics getting into surface water on hydrobionts. The results of studies of antibiotics effect on small crustaceans-filterers Daphnia magna Sr. by biotesting method and on nitrobacteria by laboratory modeling method with the use of river water are given. It is stated that the toxicity and hazard of the studied antibiotics for small crustaceans-filterers depend on the origin of antibiotics, their concentration in water and capacity to accumulate in small crustaceans’ organisms. Out of the stu­died antibiotics cefazolin was most toxic for daphnia, whereas ampicillin and ceftriaxon were less toxic. However these antibiotics are characterized by obvious capacity to accumulate in daphnia’s organism and can further cause downsizing of the population of these hydrobionts, distortion of self-purification from suspended solids and trophic structure of hydrobiocoenosis. In order to study the effect of antibiotics on nitrification process cefazolin and cefotaxime antibiotics were used at the concentrations of 1·10^–9–1·10^–8 mg/dm³. It is stated that the effect of these antibiotics depends on the concentration and origin of antibiotics. Cefazolin at the studied concentrations inhibits nitrification process. Cefotaxime at the concentration of 1·10^–8 mg/dm³ slightly inhibits and at the concentration of 1·10^–9 mg/dm³ inhibits nitrification process. The highest inhibiting effect of the studied antibiotics is observed on the 15th day of exposure; nitrification process enhancement with cefotaxime at the concentration of 1·10^–8 mg/dm³ was registered within the interval of 6–12 days of exposure.

Key words

nitrification , biotesting , antibiotics , self-purification of a water body , hydrobionts-filterers , laboratory modeling

DOI 10.35776/VST.2022.04.03
UDC 502.51(282):504.5

Trifonova Tat’iana, Chesnokova S. M., Savel'ev O. V.

Estimating the effect of synthetic surfactants on the ecosystem
of a small watercourse

Summary

The results of studying the impact of anionic surfactants on the physicochemical and biochemical processes in the ecosystem of a small eutrophic watercourse by laboratory modeling are presented. It has been established that anionic surfactants inhibit nitrification processes in proportion to their concentration in water; migration of phosphates from bottom deposits occurs intensively in the concentration range of 0.02–0.1 mg/dm³, which is equivalent of the level of the studied watercourse pollution. At the concentration of anionic surfactants from 1.2 to 4 mg/dm³ in the model solution, the migration of phosphate ions from the bottom deposits deceased. Correlation analysis was used to study the effect of the composition of water and bottom deposits on the mobility degree of phosphate ions in the watercourse ecosystem.

Key words

phosphates , laboratory modeling , minor stream , anionic surfactants , mobility degree , correlation