Chemosphere 73 (2008) 1284–1291 0045-6535/$ - see front matter © 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.chemosphere.2008.07.009 Contents lists available at ScienceDirect Chemosphere journal homepage: www.elsevier.com/locate/chemosphere 1. Introduction One of the main threats to the soil ecosystem, as specified in the EU document Thematic Strategy for Soil Protection (COM (2006)231 final), is soil contamination which can generate direct and indirect risk for most soil functions (habitat, retention and production). The contaminants of special concern include, between others, persis- tent organic pollutants (POPs). Polycyclic aromatic hydrocarbons (PAHs), belong to the “potential POPs” group (Cai et al., 2008), that exhibit strong toxic, carcinogenic, and mutagenic properties (Mal- iszewska-Kordybach, 1999; Ravindra et al., 2008), thus create a risk towards the soils organisms as well as to humans. They are produced in most of the natural and anthropogenic processes of incomplete combustion of wood, fossil fuels, petroleum products, and other organic materials (Maliszewska-Kordybach, 1999; Wil- cke, 2000; Ravindra et al., 2008). Agricultural land is under the pressure of PAHs contamina- tion mainly from atmospheric depositions (directly or via vege- tation), as well as from organic substances and biowastes applied as fertilisers (Jones et al., 1989; Johnsen and Karlson, 2007; Cai et al., 2008). Due to its high hydrophobic properties, PAHs can be sorbed on atmospheric particles and thus transported over a long distance, being a source of diffuse pollution (Maliszewska- Kordybach, 1999; Wilcke, 2007; Ravindra et al., 2008). Point pollu- tion derives usually from local industrial activities and transport, industrial wastewaters, waste materials, road runoffs and acci- dental fuel spills (Jones et al., 1989; Wilcke, 2000; Johnsen and Karlson, 2007). Although soil profile data indicate that PAHs may extend into deeper layers, it is estimated that about 90% of the total burden of PAHs resides in surface soil (Wild and Jones, 1995). This regards also to the arable layer of agricultural soils used for crop production. Contamination of those soils with PAHs may affect their habitat function (Maliszewska-Kordybach et al., 2007; Jensen and Mesman, 2007), while an accumulation of PAHs from the environment in agricultural crops appears to be important for human exposure (Kobayashi et al., 2008). A better understanding of relative problems is necessary to avoid risks linked to the con- tamination of agricultural soils. Although significant reduction of PAHs emission has been observed in recent decades (Ravindra et al., 2008), it will take time before this positive trend is reflected in the soil environment. Con- centrations of PAHs in soils from agricultural regions of Europe are relatively low and vary by orders of magnitude from those in polluted soils, however, it does not exclude the risk of a negative Monitoring of the total content of polycyclic aromatic hydrocarbons (PAHs) in arable soils in Poland Barbara Maliszewska-Kordybach * , Bozena Smreczak, Agnieszka Klimkowicz-Pawlas, Henryk Terelak Institute of Soil Science and Plant Cultivation-State Research Institute, Czartoryskich 8, 24-100 Pulawy, Poland article info abstract Article history: Received 6 Feburary 2008 Received in revised form 4 July 2008 Accepted 8 July 2008 Available online 20 August 2008 The paper provides comprehensive information on the level of contamination of arable soils in Poland with polycyclic aromatic hydrocarbons (PAHs). Extensive monitoring studies were carried out to deter- mine the content of the 16 priority PAHs in 216 soil samples collected in 2005 throughout arable lands (0–20 cm layer) in Poland. Locations of sampling points reflected the differences in regional industriali- sation and urbanisation as well as in the characteristics of soils. The content of R16PAHs ranged from 80 to 7264 lg kg ¡1 with a median of 395 lg kg ¡1 and with a dominance of 4–6 rings hydrocarbons (74% of total PAHs). Soil properties affected the PAHs content to a limited extend. The organic matter content was the only parameter correlated significantly (although weakly) with the concentrations of R16PAHs; the strength of this relationship was more pronounced in soils with elevated OM content. The various molec- ular markers pointed to a prevailing pyrogenic origin of the PAHs in Polish arable soils, with minor contri- bution from liquid fuels combustion and traffic emissions. Two different Polish systems for classification of agricultural soils (providing for the content of R9PAHs and R13PAHs) indicate that the percentage of contaminated arable soils in Poland does not exceed 10%. Multivariate methods enabled an evaluation of spatial trends in R16PAHs concentrations, an identification of regions with very low PAHs content (East part of the country), and a recognition of small industrial/urbanised areas of higher risk. © 2008 Elsevier Ltd. All rights reserved. Keywords: Soil contamination Organic pollutants PAHs Monitoring Arable soils Polish soils * Corresponding author. Tel.: +48 81 886 3421; fax: +48 81 886 4547. E-mail address: bkord@iung.pulawy.pl (B. Maliszewska-Kordybach).