Changes in phosphorus content, phosphatase activity and some physicochemical and microbiological parameters of soil within the range of impact of illegal dumping sites in Bydgoszcz (Poland)

The present research aimed to assess the influence of illegal dumping on changes in the content of phosphorus and its relationship with selected chemical properties. Soil was sampled from two horizons: 0-20 and 20-40 cm. Samples from points W1, W2 and W3 (waste 1, 2 and 3) were collected directly from under illegally deposited landfill sites that differed in the morphological composition. At a distance of 30 m from landfill W3 there were agricultural lands where maize was cultivated (arable soil, AS). The control point (C) was located far from the waste landfill sites determined and beyond the range of their effect. In soil the following were determined: total organic carbon, phosphorus (total, organic, mineral, available, active), the microbiological activity, the content of heavy metals and the activity of alkaline and acid phosphatase. The study concluded that the composition of treatments W1 and W2 had a more negative impact on the soils than landfill site W3. The results show that the changes depended on the type of the waste deposited. In AS and landfills W3 there was observed a high P availability and count of bacteria. The results have shown that an addition of organic residues to soil has a variety of effects on microbial and phosphatase activities. The lowest resistance (RS) for alkaline and acid phosphatases was found in soil from the area of dumping sites W1 and W2; the highest RS was determined in AS. Statistical analyses of simple correlations showed clearly that microbiological populations were also particularly implicated in the activity of phosphomonoesterases.