Evaluation of the agricultural soils pollution along the Orava river using pollution indices

Agricultural soil pollution by potentially toxic elements (PTEs) is a major concern nowadays. We selected 11 Fluvisols used as arable land along the river Orava, and two study sites located outside the alluvium (1 Cambisol used as a permanent grassland, 1 Technosol classified as an environmental burden). We determined basic soil properties, total PTEs content and the mobile fraction using inductive coupled plasma mass spectroscopy. Pollution level of selected PTEs was assessed by single contamination factor (Cf) and pollution load index (PLI). The total PTEs content indicated their increased concentrations at many study sites. But the mobile form content of PTEs didn´t exceed the Slovak threshold limits in agricultural soils. Nevertheless, pollution indices reached increased values also in agricultural soils. According to the Cf, the Technosol was very high polluted by Pb (12.89), Sb (11.94), Cd (11.82), Zn (9.19); considerable polluted by As (5.75), Cu (5.70), Mo (4.86); moderate polluted by Cr (2.47), Co (1.92), Ni (1.48). For Fluvisols was confirmed moderate level of pollution, with the exception of Cr (3.24) which confirmed considerable level of pollution. Average Cf for Fluvisols ranged from 1.02 to 9.00 for Cr, from 0.87 to 1.87 for As, from 0.76 to 2.37 for Pb, from 0.61 to 3.48 from Cd. In Cambisol we recorded low level of contamination for Zn (0.87), Cu (0.99), and Pb (0.94), and a moderate level of contamination for the others PTEs. The PLI reached in Technosol 6.02, in Fluvisols 1.46 (range from 1.08 to 2.09), and in Cambisol the lowest value (1.15).