Application of gamma-irradiation for decomposition of some organic pollutants in waters

Application of gamma-irradiation for decomposition of some organic pollutants in waters

Poster

Gergana Mineva, Galya Valcheva, Petya Kovacheva
Faculty of chemistry and pharmacy, University of Sofia “St. Kliment Ohridski”, Bulgaria

Controlling the content of organic pollutants in water is important because it has a bearing on human health. In the Bulgarian legislation, the requirements for the quality of water intended for drinking and household purposes and the relevant norms are laid down in Ordinance No. 9 of 16.03.2001, amended. SG. No. 6 of 16.01.2018. Organic pollutants such as halogenated hydrocarbons can be obtained as by-products in the chlorination of water if it contains organic compounds. They are dangerous to health because they may have carcinogenic effects. This study aims to evaluate the effect of gamma-radiation exposure on the degradation of organic pollutants in water. The experiment includes contamination of deionized water with chloroform, bromodichloromethane, bromoform, dibromochloromethane, trichloroethane, tetrachloroethane and 1,2 dichloroethane at concentrations between 75 and 750 ppb, irradiation of aliquots of the mixture with gamma-irradiation and subsequent analysis of concentrations of organic pollutants. Gamma-irradiation was performed with industrial gamma-irradiator BULGAMMA based on JS-850 60Co type gamma-irradiator at Sopharma AD. Doses, applied to the irradiated samples were determined using ethanol-chlorobenzene dosimeters. Analysis was carried out by gas chromatograph "GC System 6890N" with a mass-detector, according to BDS EN ISO 10301: 1997. The obtained results showed that the radiation exposure with a dose of 5.8 kGy leads to a significant degradation of the organic pollutants chloroform, bromodichloromethane, bromoform, dibromochloromethane, trichloroethane and tetrachloroethane and reaching their limit values determined according to the Bulgarian legislation. Dose of 20 kGy was needed to destroy 1,2 dichloroethane to the permissible concentration level.
Key words: organic pollutants, water, gamma-irradiation, gas-mass chromatography