Change of the groundwater chemical composition in a pig breeding enterprise

This paper presents data on the groundwater chemical composition in the boreholes installed in moraine loam, sandy loam and sand fields, watered with slurry from a pig breeding enterprise (annual watering rate - 460 m3 ha-1). The investigations aim to determine the influence of the fields, watered with slurry from a pig breeding enterprise, on the groundwater quality. In the observed boreholes samples of the groundwater were taken and water level was measured twice a year: in spring, before the fertilization, and in autumn, at the end of the fertilization period. The following indices were determined in the water samples: NH4 +, NO3 -, NO2 -, PO4 2-, K+, Na+, Ca2+, Mg2+, HCO3 -, SO4 2-, Cl-. The unified water quality investigation methods, approved by the ministry of Environment, were used to conduct chemical analysis of the water samples. As the groundwater was mowing towards southeast, south and southwest from the fertilized field, the boreholes in the lowest place of relief (borehole 1 and borehole 4) had the highest water mineralization and irregularly distributed concentration of the most important anions: HCO3 ->Cl- >SO4 2->NO3 -. Besides, the highest groundwater mineralization was determined in the borehole 4, which was installed in the soil with a peat layer. No influence of water level fluctuations and the amount of the nutrients comming with slurry on the concentrations of chemical elements was determined, as the obtained results of correlation analysis were not statistically significant. At the increasing total water hardness, mineralization also increased, while the increasing mineralization gave rise to the amount of chlorides and sulphates in the water. According to the investigation data, in the period of observation the areas watered with slurry had an insignificant influence on the groundwater quality: formation of hydrocarbonate, slightly mineralized and hard waterVytauto Didžiojo universitetasŽemės ūkio akademij