Assessment of forest soil contamination by heavy metals in the Polish National Park near Warsaw.

The forest ecosystems are essential for human well-being development and reduction of the risk of natural disasters. Maintaining forest growth and ecosystem services is dependent on soil sustainability. The content of heavy metals is the main parameter determining the degree of soil contamination and degradation. The objective of the study was to assess the extent of soil contamination and identify the sources of potential anomalies. The content of the cadmium, lead, manganese and chromium (using atomic emission spectroscopy with induction-coupled plasma), as well as granulometric composition, pH value and nitrogen and total carbon content, were conducted on soil samples taken from the surface layer (0-10 cm) in the protected area of the Kampinos National Park in Poland. The soil quality assessment was conducted by calculating indicators of contamination including the geo-accumulation index, contamination factor, degree of contamination, ecological risk of individual heavy metals and potential ecological risk index. The results exhibited that the tested soils were very acidic or acidic sands. The content of the determined elements did not exceed the permissible limits as outlined in Polish standards, which are 2 mg/kg, 100 mg/kg and 150 mg/kg for cadmium, lead and chromium, respectively. The indicators show differences in the degree of contamination of the surface soil layer in the studied area, which is predominantly uncontaminated by heavy metals. However, the geochemical index values equal 0.42, 0.71 and 0.98 for certain samples suggesting the anthropogenic impact on the soils of the Kampinos National Park. The pollution appears to have been generated by the metallurgical industry, heating and power plants in the Warsaw agglomeration and transport.