BORON CONCENTRATIONS IN GROUNDWATER INTENDED FOR CONSUMPTION FROM INTAKES LOCATED IN NORTHERN POLAND

The studies on boron concentrations were carried out on the samples collected from the groundwater intakes located in Northern Poland in the Lower Vistula Valley and in the Starogard Lakeland with diversified hydro-geological conditions and depths. The 57 samples of water for assays were collected from the following intakes: Tczew "Park" and Tczew "Motlawa", Gniew, Wielkie Walichnowy, Male Walichnowy, and Pelplin. The deepest drillings extended to 180 in (cretaceous stages), out of which 20% comprised quaternary formations up to 123 m deep. The analysis of water samples in these regions was performed from 2009-2011. The geological architecture of these areas was identified based on the legal documentation on water utilization submitted by the operators of the water intakes. The Polish sanitary regulations specify that the maximum content of boron in drinking water is 1.0 mg dm(-3). That it was found in the waters mesoregion Starogard Lakeland may be assumed to be good in the context of chemical status, because in all of the 24 water samples tested, the boron concentration did not exceed the threshold value. In the Lower Vistula Valley mesoregion in 17 samples out of 33 tested, the level of boron exceeded 1.0 mg dm(-3), which means that prior to consumption these waters require treatment to reduce the concentration of this element to the permissible limits. Slightly higher concentrations of boron (on average 1.63 mg dm(-3)) were detected in water deposited in the cretaceous formations situated in Wielkie Wachlinowy and Male Wachlinowy. It was also found that the content of boron in groundwater depended on the nature of geological layers from which the tested water samples were collected. The statistical analysis demonstrates that the aquifer stages exerted a significant impact on the content of boron in the tested water samples and the differences between them are significant.