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