Concentrations of heavy metals and polycyclic aromatic hydrocarbons in needles of Masson pine (Pinus massoniana L.) growing nearby different industrial sources

Emissions from industrial activities pose a serious threat to human health and impose the need for monitoring both inorganic and organic pollutants in industrial areas. We selected Masson pine （Pinus massoniana L.） as potential biomonitor and collected the current （C） and previous year （C＋ 1） needles from three industrial sites dominated by petrochemical, ceramics manufacturing, and iron and steel smelting plants and one remote site to determine heavy metals （Cu, Cd, Pb, Zn, Cr, Ni and Co） and polycyclic aromatic hydrocarbons （PAHs） in unwashed and water-washed needles. Both unwashed and washed C＋ 1 needles showed generally higher concentrations of heavy metals and PAHs than C needles, although the washed needles more clearly spotlighted the accumulation effect of PAHs over exposure time. Water-washing resulted in a significant decrease in needle PAH concentrations with more significant effects shown in C needles. By contrast, needle heavy metal concentrations were much less affected by washing. Although heavy metals and PAHs might differ in adsorption and uptake strategies, their higher concentrations in the needles at the industrial sites indicated conspicuous contamination due to industrial emissions there. The PAH distribution patterns in pine needles accorded with the real types of energy consumption in the study sites and were efficiently used for pinpointing local pollutant sources.