Content of PAHs in soil of a hazel orchard depending on the method of weed control

PAHs belong to persistent organic pollutants (POPs) found in the natural environment. They eventually accumulate in the highest quantities in soil. The purpose of this study has been to determine quantities of PAHs in soil depending on the method applied to control weeds in rows of a 4-year plantation of hazel (mulch fabric, bark chips, sawdust, manure compost, bare fallow, chemical fallow, grass sward). The highest concentration of PAHs (16 PAHs) was found in soil kept as bare fallow. The second most abundant concentration of these compounds was determined in soil under grass sward, followed by soil under sawdust, chemical fallow, and fabric. Less of these compounds accumulated in soil mulched with bark chips. The best method for protection of orchard soil against the accumulation of unwanted and toxic PAHs was mulching with manure compost. In most cases, lower concentrations of PAHs (total 16) were found in the subsoil (30-60 cm) than in the topmost soil layer, except the soil covered with mulch fabric, where fourfold more PAHs accumulated.