Phosphate and ammonia concentrations in waters from a meadow complex located on peat soils in various range of groundwater level

The aim of the study was to assess the P-PO4 and N-NH4 pollution of water in grasslands located on peat soils and to identify the impact of groundwater level on this pollution formation. The research was conducted in 2000-2010 on grounds of ITP-PIB in Biebrza village (Poland). Within lowland fen a total of 18 monitoring points of groundwater and watercourses were established in 6 separate test stands. The subject of the research was water collected from drainage ditches/channels and groundwater, which was taken from wells installed in organic-soil layer and wells whose bottom was 15-20 cm below this layer. Water samples were collected several times a year, and in the case of groundwater, its level was also measured. It was found that: 1) due to concentration level of P-PO4 and N-NH4, about 46 and 39% of water samples from organic-soil layer and more than 40 and 37% of water samples from mineral-organic-soil layer respectively, were characterized by poor chemical status; 2) due to the exceeding of the limit values of P-PO4 and N-NH4 concentration, water samples from watercourses in over 30 and 27% respectively were not within 1st and 2nd class of surface water quality; 3) P-PO4 and N-NH4 concentrations in each water type were statistically significant and positively correlated with each other; 4) in organic-soil layer the groundwater level changing every 10 cm was a statistically significant factor differentiating the average P-PO4 concentration in roundwater associated with mineral-organic layer of peat soil and average N-NH4 concentration in each type of water.