PAHs and trace elements in volcanic urban and natural soils

Surface volcanic soils (0–5 cm) were analysed for 8 trace elements (Cd, Cr, Cu, Fe, Mn, Pb, V, Zn) and 27 PAHs. Soils were collected every four months at five urban sites in Naples and at a control site in the Vesuvius National Park from May 2001 to May 2002. Cr, V and Fe were more abundant in the control soils while Pb, Zn and ΣPAH were higher in the urban soils. Pb was 2–4 and ΣPAH 2–20 fold higher in urban than in control soil, whereas V was 2 fold higher in the control than in urban soils. Among the urban soils, both trace element and PAH accumulations also differed. Atmospheric deposition is responsible for trace element and PAH accumulation in urban soils. Phenanthrene, fluoranthene, pyrene, benzo[a]pyrene, benzo[b+k+j]fluoranthene and benzo[g,h,i]perylene were the most abundant PAHs both in control and urban soils. Naphthalene was also high in the control soil. Coronene was the most abundant at the urban site near the highway. The accumulation of PAHs in soils appeared to be affected by soil organic matter and microbial metabolism.