Chloroform contamination of potable water as a result of its disinfection

Abstract

Practically all water supplies of Ukraine use a chlorine or connections that contain chlorine for water treatment. In the process of water preparation organic substances that are included in its composition co-operate with disinfectants, and as a result a few types of trihalomethanes (ТHМ) appear, and chloroform prevails among them. Sufficiently long time the underestimation of the most meaningful sides of their biological action took place — remote consequences, in particular mutagenic and carcinogenic action. Although in experiments on higher animals, data about the chloroform cancerogenicity for organisms were got and after classification of IARC (France) it was attributed to the group 2 (factors that are probably carcinogenic for a human), the increase of morbidity from cancer among people who used the chlorinated drinking-water in epidemiology researches didn’t confirm clearly in the half of cases during observation. It was determined later that chlorinated drinking-water influences elasticity of blood vessels. They become harder, and that is why functioning of the cardiovascular system is violated. And, as known, the lost elasticity of blood vessels causes atherosclerosis, disease of heart. In opinion of several authors, risk of development of cancer for people and animals that use the chlorinated water, grows substantially. The presence of organic substances in water supplies causes chloroform formation in drinking water. Frequently «water-blooming», which is caused by growth of phytoplankton in consequence of coming of biogenic substances into the water, determines the appearance of organic compounds. Article writes above determining actuality of problem of danger of chloroform contamination of drinking-water for a human and animals as a result of its disinfection and bleaching with liquid chlorine during water treatment. Some indices of drinking water quality which influence the chloroform formation in it are analyzed. It is noted that oxygen concentration and turbidity here have to be examined as the most essential indices that testify the level of water contamination and determine the necessary terms of its bleaching and disinfestation. Reproduction intensity of diatomaceous, blue-green and green algae is investigated in the water intake «Vidsichne» of the Teteriv river in 2014 and it is shown that an active development of planktonic algae causes the necessity to increase the doses of reagents, that are added to water during its preparation. The features of different departments’ coexistence of phytoplankton in a water intake and their influence on the changes of turbidity indices and size of oxygen are also educed.