Case study: Inorganic pollutants associated with particulate matter from an area near a petrochemical plant

The area of Gela (Sicily, Italy) contains one of the largest petroleum refineries in Europe and also has several oil fields both on land and offshore. This paper discusses how the oil refinery and traffic-related air pollution affect the chemical composition of airborne particulate matter over the town of Gela, using pine needles and urban road dust as the means of survey. Forty-one samples of pine needles from Pinus halepensis (Mill.) and two composite samples of roadway dust, each subdivided into six size fractions, were analyzed for major and trace elements. Information on the natural or anthropogenic origin of the observed heavy metals was deduced from factor analysis and element distribution maps. Factor analysis was applied to a data set of 20 element concentrations in pine needles and identified three main sources of metals: soil, vehicle traffic, and industrial emissions. The petrochemical plant appears to be associated with raised levels of As, Mo, Ni, S, Se, V, and Zn. Similarly, enhanced Cu, Pb, Pt, Pd, Sb, and partly Zn concentrations are closely associated with traffic. High correlations between Ni and V, As and Se, and Pb and Sb were observed. Element distribution maps, showing a decrease in heavy metal contents immediately farther inland, confirm that local sources play a considerable role in heavy metal pollution. Morphological alterations and accumulation of phenols were observed in sections of Pinus halepensis needles collected from sites with high traffic density and industrial emissions.