PERSISTENT ORGANIC POLLUTANTS: SOURCES, MIGRATION IN ECOSYSTEMS, REMOVAL METHODS IN WASTEWATER TREATMENT AND REMEDIATION OF SOILS AND NATURAL WATER

Persistent organic pollutants are among the most dangerous pollutants due to their resistance to destruction in natural conditions, the ability to migrate in ecosystems, bioaccumulation, biomagnification and significant harmful effects on health. Persistent organic pollutants include organochlorine pesticides, polychlorinated naphthalenes, polychlorinated biphenyls, polybrominated diphenyl ethers, polycyclic aromatic hydrocarbons, etc. Even in small amounts, these compounds can cause endocrine disorders and have a carcinogenic effect. Most of these compounds are exclusively of anthropogenic origin. Although the Stockholm Convention has severely restricted the production and use of persistent organic pollutants, many soils and water bodies are already contaminated with these compounds, and some banned substances continue to be produced as byproducts of industrial processes. Also, although the lists of substances prohibited for production are periodically updated, a large number of compounds, which by their properties are persistent organic pollutants, have not yet entered these lists. There are many methods for removing persistent organic pollutants from water, but most of them are insufficiently effective or lead to the generation of large quantities of contaminated waste that need to be disposed of. Photocatalysis is the most promising method of wastewater treatment that contains persistent organic pollutants. Unlike coagulation, adsorption, biological treatment and nanofiltration/reverse osmosis, this method avoids the generation of solid and liquid waste contaminated with these pollutants. In the case of remediation of polluted waters and soils, the main methods are bioremediation and adsorption, since these methods can immobilize persistent organic pollutants directly in the ecosystem without taking soil or water for treatment.