EN
The presented research aimed to assess the influence of illegal dumping sites on changes in the phosphorus, nickel and lead content and the phosphatases activity in 0−20 cm top soil−layer. The samples were taken in the Bydgoska Forest (northern Poland) from four points. At plots W1 (debris and ceramic waste, glass, plastics, metals, textiles and used electrotechnical equipment), W2 (electrotechnical equipment, tyres and textiles) and W3 (wastes of organic origin from households as well as cut grass and residue from garden) samples were collected directly under illegally deposited landfill sites. The control plot (K) was located far from the determined waste landfill sites and beyond the range of their effect. We determined: organic carbon (Corg), total and available phosphorus as well as the content of total and available lead and nickel and the activity of alkaline and acid phosphatase. Uncontrolled landfill sites significantly influenced soil properties, which may lead to changes in the phosphomonoesterases activity of soil and the nutrient content. The study concluded that the composition of waste at W3 site had a less negative impact on the soils than at W1 and W2 sites. In the soil from landfills W3 we observed high phosphorus availability (AF 14.9%). The lowest resistance (RS) for alkaline and acid phosphatases was found in soils from the area of dumping sites W1 and W2, while the highest RS was determined for W3. The content of nickel and lead in the soil samples qualifies them into the category of soils with natural content of these compounds. Simple correlation showed clearly that organic matter was particularly implicated in the activity of phosphomonoesterases and the content of lead or nickel. Based on the clustering with Ward's method it was stated that cluster 2 includes two soil samples (W1 and W2) due to its lower phosphatase activity and organic carbon, available phosphorus and total lead content. A high variation in the activity phosphatase under study in soil W2 confirms a high coefficient of variation (>36%).