Source apportionment of benzo(a)pyrene in Taranto and carcinogenic risk estimate in general population]

In 2009 the limit value of benzo(a)pyrene (BaP) in ambient air of 1.0 ng/m3 has been exceeded in the urban district of Taranto near to the industrial area, where a several large plants are located, including an integrated cycle steel plant.To identify emission sources and quantify relative contribution to the PAHs levels; to estimate health impact associated to PAHs exposure in general population.Multivariate receptor models have been used. Concentration of PAHs measured in 4 location in Taranto in 2008-2009 have been analyzed. 5 different models estimated profiles of unknown sources and identified significant chemical species. To compute the lung cancer risk the WHO unit risk estimate for BaP (8.7 x 10(5) ng/m3) has been adopted.Models employed identify 3 to 4 emission sources. Estimated profiles have been compared with measured ones. Based on the average annual BaP level measured (1.3 ng/m3), 2 attributable cancer cases in the district Taranto population are estimated to result from a life-time exposure.Among different emissive sources, the analysis identifies theoretical sources whose profiles, compared with observed data, allow to identify dominant contributions to PAHs pollution and to design corrective actions to reduce environmental and health impact.