Levels and distribution of organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs) in topsoils from SE Romania

Abstract

The aim of this work was to determine the concentrations of organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs) in topsoils (n=17) at two sampling depths in Southeastern Romania, including industrial (Galati iron and steel plant) and agricultural sites in Galati and Braila counties, as well as nature reserves such as Lower Prut Meadow (Galati County) and Bugeac Lake (Constanta County), and to compare them with national guidelines and values reported for other regions. The total detectable OCP concentrations vary in the ranges 58-1662ngg(-1) dry weight (dw) for 0-5cm depth and 6-12,644ngg(-1) dw for 5-20cm depth. Of these, the concentrations of HCHs, DDTs, and heptachlor varied in the ranges 6-6818ngg(-1), 27-5826ngg(-1), and 108-873ngg(-1) dw, respectively, the highest values being registered near a cultivated area, located in the proximity of Siret River and Galati town, probably due to extensive use of pesticides in the past. Chlordane was detected only at one industrial site in Galati (53ngg(-1) dw), while the levels of aldrin, dieldrin, endrin and mirex were below the detection limits in all the locations and for both depths. The total PAH concentrations for 5-20cm depth range from 9ngg(-1) (Lower Prut Meadow) to 25,352ngg(-1) dw (cattle farm), being lower than those reported for the upper 5cm layer. The PAH distribution pattern in this study is in agreement with that previously obtained for surface soils from Lower Prut Meadow (prevalence of 3-ring PAHs), industrial area and farmland (prevalence of 4- and 5-ring PAHs), their sources being industrial activity, traffic and agricultural waste burning. Carcinogenic PAHs contribute 44.8-56.4% for 5-20cm and 43.7-55.8% for 0-5cm depth to total PAHs. In some locations the HCH, DDT and PAH amounts exceed the legal values.