Polycyclic aromatic hydrocarbons content in shoots and leaves of willow (Salix viminalis) cultivated on the sewage sludge-amended soil

The aim of the present study was to investigate the uptake of 16 PAHs by willow (Salix viminalis) from soil amended with contaminated sewage sludge. Uptake experiments were conducted on field plots using sludge applications of 0, 30, 75, 150, 300, and 600 Mg ha(-1). The total PAH content of control soil and sludge were 49.6 mu g kg(-1) and 5713 mu g kg(-1), respectively. The concentrations for the 16 PAHs listed as priority pollutants were measured for soil and plant tissue samples obtained at 0.5, 1.5, 2.5, and 3.5 years. Soil total PAH content decreased significantly within the first half year, followed by minimal changes over the subsequent three years of treatment. PAH analysis was carried out on a HPLC-UV. Total PAH content in control plants was 3.6-7.3 mu g kg(-1) for shoots and 13-27 mu g kg(-1) for leaves. Treated plant tissue content was higher with shoots and leaves containing similar to 5.5-17.6 and 13.5-33.8 mu g kg(-1), respectively. Plant total PAH content did not show a significant trend relative to controls with respect to time. However, uptake did increase in relation to an increased sludge application. Bioconcentration factors (BCF), adjusted by control values, were calculated for total PAH content. BCF values were highest for the initial sampling (6 months) and did not show a significant temporal relationship. BCF values did decrease with increasing sludge application. With respect to individual PAHs, elevated plant tissue concentrations were measured for "light" PAH (e.g. naphthalene, phenanthrene, acenaphthalene) with leaf BCF values correlated with solubility and organic partitioning coefficients.