PROBLEM OF ANTIBIOTICS IN NATURAL WATER: A REVIEW

The paper is devoted for influence of antibiotics contamination of natural water on environment, aquatic biosystems and public health and possible solutions of this problem. Untreated or ineffectively treated wastewater is a source of different pathogenic microorganisms and toxic chemicals, including organic and inorganic compounds. A lot of organic contaminants are genotoxic, provoke endocrine disruption and have immune toxicity. In modern world people use a lot of diverse antibiotics for the treatment of various bacterial infections, but antibiotic overuse and insufficient removal by wastewater treatment plants are resulted in accumulation and biotransformation of these compounds in aquatic environment. Antibiotics are pollutants which are very harmful for environment. They cause reduction in microbial biodiversity, including bacterial communities with important ecological functions. It provokes changes in water and soil properties, including pH, nutrients content, soil moisture and many others. Low concentrations of antibiotics cause an occurrence of pathogenic microorganisms which are resistant to antibiotics. It has very negative influence on public health due to increasing of health risk and complication of a medication. Antibiotic type, water and sediment compositions, pH, organic matter, specific surface area and temperature and insolation level have very big influence on distribution and behavior of antibiotics in natural water-sediment systems. Many antibiotics are biodegradable; they are transformed in human organism or by aquatic ecosystem (various plants, algae, bacteria, fungi, etc.). But some antibiotics, including ciprofloxacin, are very stable. These persistent organics are dramatically more harmful for ecosystem stability. In case of ciprofloxacin antibiotics in surface water direct photolysis causes formation of organic compounds, which are more toxic and less photolabile than initial antibiotics. So, the toxicity of pollutants increases synergistically and it cannot be ignored. Nowadays antibiotics removal is very important in drinking water and wastewater treatment due to significant environment and health effects of these pollutants. There are a lot of approaches in antibiotic removal from water, including adsorption, nanofiltration, advanced oxidation processes, etc. All these methods have some advantages and disadvantages. Catalytic photodegradation is one of the most popular methods of antibiotic removal. This process is simple, highly effective and makes possible transformation of antibiotics into components with lower toxicity and environmental impact. Also photocatalysis do not produce a lot of wastes unlike coagulation (sludge) or nanofiltration (concentrate).