Contamination of Agricultural Soil — As Evaluated on the Basis of Metals, Sulphur and Polycyclic Aromatic Hydrocarbons Content

Abstract

Key words: contaminated soil, environmental risks, guide levels, heavy metals, human health risk, P AH (polycyclic aromatic hydrocarbons), quality of the soil, risk assessment , soil protection, sulphur. Food quality-one of the most important factors in human health risk assessment-depends on the quality of agricultural ecosystems. Soil contamination plays a key role in these evaluations. The aim of the study was to assess the level of contamination of agricultural soils in highly industrialised region of Poland. Three groups of inorganic and organic pollutants exhibiting different impact on the environment were taken into consideration: metals (Zn, Pb, Cd), sulphur (SO.J and polycyclic aromatic hydrocarbons (PAll). For the two first groups soil classification systems based on the contaminant concentration in soil and on the most important soil characteristic (Qrganic matter content-OM, fraction ~<0,02 mm content and pH) were applied l. The classes of soil contamination with PAHs (sum of 16 compounds) were distinguished according to the content of these hydrocarbons related to "average Polish soil" OM content (2 % weight)2. Soil samples (n=65) have been taken from 0-20 cm layer from 3850 ha area (71 % of arable soils and 29% of pastures)3. For metals determination the samples were digested with HCI0 4 and HF mixture, evaporated to dryness and dissolved in HCl; Zn, Cd an Pb content was determined by flame atomic absorption spectroscopy4. PAHs analysis was performed by means of HPLC method; 16 compounds (according US EPA) were determined in soil extracts (cleaned-up on Florisil micro-columns)5. For sulphur (sulphate ions) determination nephelometric analysis was applied following soil extraction with ~P04 6. Statistical evaluation of the results suggested log-normal distribution of all groups of contaminants in soil samples population (Tab. 1). While Zn, Pb and Cd concentrations in soil samples were correlated rather highly (R within the range 0,78+0,91), the correlation coefficients between metals and PAH content were low (R=0,41+0,55 with the highest value corresponding to PAH+Pb relation). Sulphur content in soil samples was markedly different from any other pollutant distribution. 517 W. J. van den Brink, R. Bosman and F. Arendt (eds.), Contaminated Soil '95,517-518.