[Contamination of waters by formaldehyde].

The high toxicity of formaldehyde and its relatively high number of release sources called for extensive studies for elucidating its sources and the degree of contamination of waters in Poland with this compound. In the study formaldehyde was determined in community sewage, industrial sewage and precipitations in the street, as well as in surface waters, waters taken for supplying networks and drinking waters. It was tried also to establish the possible influence of meteorological factors on formaldehyde presence in surface waters. Formaldehyde was determined by the colorimetric method with chromotropic acid after previous distillation of the analysed samples of waters and sewage. It was found in these studies that the main source of contamination of surface waters with formaldehyde are community sewage and industrial sewage. In summer the concentration of formaldehyde in these waters was higher than in winter. It is stressed that the maximal values of these concentrations in studied waters were above the acceptable value, even several times. Despite this unfavourable situation it was found that in tap water obtained from rivers this contamination was negligible, and after treatment it contained practically no formaldehyde. Thus formaldehyde in drinking water is not a health risk for the population.