Toxic elements and persistent organic pollutants derived from industrial emissions in agricultural soils of the Northern Czech Republic

Abstract

This study reports on the surface distribution of toxic elements (TEs; As, Be, and Cd) and persistent organic pollutants [POPs; e.g., polycyclic aromatic hydrocarbons (PAHs)] in agricultural soils affected by mining and heavy industry from the industrial regions of North Bohemia and North Moravia. In this study, these regions are considered as test regions to study the impacts of heavy industry emissions on agricultural soils. From 2000 to 2010, agricultural soils were sampled and their physicochemical properties and contamination levels of TEs (As, Be, and Cd) and POPs (PAHs) determined. The pseudototal content (from Aqua regia extracts) and plant available fraction (from 1 M NH4NO3 extracts) of TEs, as well as the total PAH content in humic horizons of arable soils and grasslands, were analyzed. The surface spatial variability of these contaminants was evaluated using the kriging method. Threshold values for the probability estimation were adapted from the limit values provided by newly proposed Czech legislation. We show that the soil environments of the study area are polluted by anthropogenic material directly connected to historical mining and industrial activities, including lignite mining in North Bohemia and hard coal mining and heavy industry in North Moravia. The increased As contents in the soils contribute to the most important environmental problems in North Bohemia, where anthropogenic and geogenic sources of As interact. In North Moravia, anthropogenic pollution linked to coal combustion and metallurgy has increased Cd and PAH contents in agricultural soils. However, concentrations of these pollutants do not exceed limits for food safety in soils from these regions. This study shows that agriculture can coexist in regions impacted by heavy industry emissions, like the study regions documented here. Such activity requires that a suitable methodology is implemented to evaluate soil contamination and a risk assessment is carried out. In addition, suitable precautions should be undertaken in areas close to industry, such as grassing over contaminated arable lands to reduce wind erosion.