Risk simulation of soil contamination by polycyclic aromatic hydrocarbons from sewage sludge used as fertilizers

Abstract

This work investigated the presence of PAH in sewage sludge and in soil with sewage sludge applied as agricultural fertilizer and simulated a long-term risk of soil contamination by PAH. The samples were extracted using dichloromethane and then with n-hexane in ultrasonic bath. The clean-up of the extract was done on a column containing alumina. The residual PAH were obtained using a gas chromatograph coupled to a mass spectrometer (ion trap GC-MS/MS). The results evidenced that PAH concentration levels found in sewage sludge might raise potential contamination risks to the soil. Simulations of the concentrations of PAHs in soil, by mathematical modeling, allowed to indicate a priority order for monitoring soil quality in terms of these contaminants: phenanthrene > chrysene > benzo(k)fuoranthene > benzo(a)pyrene > pyrene > benzo(b)fluoranthene > benzo(g,h,i)perylene > indeno(1,2,3-c,d)pyrene > fluoranthene > benzo(a)-anthracene > dibenzo(a,h)anthracene > fluorene > anthracene > naphthalene > acenaphthene > acenaphthylene. © 2011 Sociedade Brasileira de Química.