PAHs accumulation in soil-plant system of Phragmites australis Cav. in soil under long-term chemical contamination

Abstract

Distribution and level of 16 individual and total polycyclic aromatic hydrocarbons (∑PAHs) were assessed in soils, roots and above-ground tissues of reed (Phragmites australis) on monitoring plots in the city of Kamensk-Shakhtinskyi (Southern Russia, Rostov Region). The total concentration of the 16 PAHs in soil samples ranged between 499.0 to 7177.9 µg kg-1. Samples from the plot no. 4 had the highest PAHs concentrations of 7177.9 µg kg-1. The mean concentration of ∑16PAHs in plot no. 3 was noticeably higher than those in other monitoring sites for both root (363.0 µg kg-1) and above-ground tissues (239.8 µg kg-1). The distribution of PAHs ring size was in the order of 5-6˃4˃3˃2 in soil samples and HMW PAHs fractions represent 57.3% of the total PAHs. The concentrations of 3-4 ring PAHs were higher than HMW PAHs with 5–6 aromatic rings in all P. australis tissues. Diagnostic ratios of PAHs indicated that anthropogenic activities were probably major sources of PAHs. Accordingly, the maximum accumulation was found for phenanthrene among the 16 priority PAHs in the most of the soil and plants samples. More PAHs were accumulated in roots, as reflected by its higher mean concentration of PAHs in each plot. In addition, the BCF and TF values of LMW PAHs with 2- and 3-rings were higher than those of HMW PAHs. Taken together, our results indicated that there were an intensive accumulation of PAHs in the zone of industrial sewage tanks and sludge reservoirs as well as an obvious translocations of PAHs from the polluted soils to plant tissues, therefore, more attention is required to be paid to the PAH contamination in this area.