Distribution pattern and the risks of OPCs, PHAs and PCBs in aged refuses from landfill

Persistent organic pollutants (POPs) are the urgent risk for landfill, and should be considered before the landfill reclamation and resource. In this work, the distribution pattern of selected POPs in landfill and their ecological risks were investigated and assessed. The Σ20OCPs, Σ16PAHs and Σ19PCBs were around 157.4–329.2, 4103–19,190, and 79.1–340.3 μg kg−1 in aged refuses, with the mean value of 206.6, 8645.4, and 155.1 μg kg−1. While those in soil covers were only 6.3–75.4, 125.5–515.3 and 2.6–43.4 μg kg−1, with the mean value of 33.7, 257.7, and 24.0 μg kg−1, respectively. The maximum OPCs, PHAs and PCBs were in aged refuse with 13, 7, 10 disposal years. Whereas, the corresponding top content in soil covers were in 10, 13 and 16 years, meaning that aged refuses were not the direct source for soil covers. Among 20 OCPs measured, α-HCH, δ-HCH, Dieldrin, and Endrin were presented in all aged refuses, with the mean concentration of 93.6, 52.1, 3.9 and 4.7 μg kg−1, respectively. For PAHs, PHE, FLU and PYR were the main composition, and reached to 1535, 1224, 1187 μg kg−1. The Σ7CarPAHs occupied around 33.3–49.9% of total Σ16PAHs tested, and could be used as the indictor for PAHs pollutant in landfill. PCB-5 content was around 40.7–263.3 μg kg−1 in aged refuses, and occupied around 51.5–81.8% of Σ19PCBs measured. The HCHs and DDTs in aged refuses were below the national standard GB15618-1995, and the corresponding Σ19PCBs concentrations met the standard of GB 13015-91, suggesting that aged refuse are accepted for the further utilization process.