Hygienic assessment of polyurethane coatings in the practice of drinking water supply

Abstract

Introduction. For many years, two-component polyurethane coatings have been used as suitable systems for the protection and reconstruction of pipes in the practice of domestic drinking water supply. However, polyurethane can be a source of pollutants entering drinking water. Special attention in the hygienic assessment is paid to the main components of plastic, the released solvents and film-forming agents used in the formulation of the material. However, the definition of only priority components (taking into account Uniform sanitary requirements) does not provide complete information about the chemical stability of polymer materials during the hygienic assessment. Materials and methods. Eight different two-component polyurethane coatings of various manufacturers and manufacturers offered for use in drinking water supply are investigated in the work. The evaluation of these samples was carried out taking into account Uniform requirements (2010). Indicators that are not mandatory for the evaluation of polymer materials used in drinking water supply were also investigated. Results. Conducting a hygienic assessment of two-component polyurethane coatings shows fundamentally different chemicals to migrate into the model environment even from materials with the same type of components. When analyzing water extracts, from 9 to 40 organic compounds were identified at different temperatures. Most of them do not have the maximum permissible levels of their content in drinking water and there are no fully conducted toxicological studies of these chemicals to assess their safety for humans. There also were found three samples, from which inorganic components of cadmium and nickel migrated into distilled water above their maximum permissible values. Limitations. This study was conducted on the example of polyurethane coatings, as a particular example of the use of polymer materials in drinking water supply. It is necessary to conduct similar studies on other groups of polymers. Conclusion. At the moment, there are certain contradictions in the methodology and approaches to assessing the migration of chemicals from polymer coatings to drinking water. Therefore, their refinement and standardization is relevant, taking into account the increasing share of the use of polymer materials in human life.