[Nitrate water pollution of drinking water in the Bydgoszcz district]

The study was undertaken to evaluate the degree of drinking water pollution in the towns and countryside of the Bydgoszcz District, supplied by various installations, on the basis of the results of investigations of sanitary-epidemiological stations. Evaluation was done according to the state in 1985 as compared with that of 1981 to establish the eventual dynamics of the changes. The data presented in the tables indicate that the water supplied by the big water lines (public and institutional) does not contain nitrate quantities exceeding the norm (above 10 mg N/dm3). Their presence at a 20 mg N level/dm3 was found only in four (1.5%) lines supplying large state farms. Small installations were much more frequently polluted with nitrates, especially public wells and those of local institutions, a total of 8.8% in towns and as many as 17% in the country, where a tendency to deterioration of this state is also visible in contrast to the towns. Among the plants and institutions supplied by these water sources the situation is most unfavourable in agriculture, schools, educational and food producing and distributing establishments. The nitrate concentration in the analysed water varied in general within the limits of 10-30 mg N/dm3, maximal amounts within 60-200 mg N/dm3, showing an about 50% decrease in the compared time periods. Nitrates occur most frequently and in highest concentrations in water of wells belonging to individual households which supply about 50% of the rural population and about 11% of town dwellers.(ABSTRACT TRUNCATED AT 250 WORDS)