PAHs and metals in the soils of inner-city and suburban New Orleans, Louisiana, USA.

Representative soil samples of an inner-city and suburban community (n = 19 each) are evaluated for 16 polycyclic aromatic hydrocarbons-PAHs (naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz(a)anthracene, chrysene, benzo[k]fluoranthene, benzo[j]fluoranthene, benzo(a)pyrene, indeno[1,2,3-cd]pyrene, dibenz[a,h]anthracene and benzo[g,h,i]perylene) and nine metals (Pb, Zn, Cd, Mn, Ni, Cu, Cr, Co and V). Surface (2.5cm deep) samples were air-dried and sieved (2mm USGS #10). Accelerated solvent extraction was used for PAH preparation prior to analysis with gas chromatography-mass spectrometry. Metals were extracted at a 5:1 ratio of 1mol nitric acid to soil, shaken at room temperature, centrifuged, filtered and analyzed by inductively coupled plasma-atomic emission spectrometry (ICP-AES). Total PAHs (median 2927ngg(-1) versus 731ngg(-1)) and the total metals (median 1323μgg(-1) versus 183μgg(-1)) summarize differences (P < 0.0001) between the inner-city and suburb, respectively. A strong association exists between PAHs and metals for all 38 soil samples (correlation coefficient = 0.831, P < 0.00001). In terms of the specific sites of accumulation, both PAHs and metals show the same pattern: busy streets > foundations > residential streets > open areas. This study provides real-world data about various chemical mixtures which may be a factor of possible health disparities in sensitive populations, especially children, in different communities of New Orleans.