Wu Yanwen, Cho Yeo-Myoung, Luthy Richard G, Kim Kibeum, Jung Jihyeun, Gala William R, Choi Yongju
Department of Civil and Environmental Engineering, Stanford University, Stanford, CA 94305-4020, USA.
Department of Civil and Environmental Engineering, Seoul National University, Seoul 08826, Republic of Korea.
Environ Pollut. 2017 Dec;231(Pt 2):1380-1387. doi: 10.1016/j.envpol.2017.08.117. Epub 2017 Sep 21.
Sorbents amended to sediments in situ for sequestration of hydrophobic organic contaminants (HOCs) may be swept away from the treated sites due to hydrodynamic forces applied to the sediment surface. The purpose of this study is to examine the possibility of recovery of HOC availability in sorbent-amended sediment after complete removal of the sorbent. Sediment contact with an easily separable model sorbent Tenax beads for 28 days in a slurry phase resulted in 74-98% reduction in polycyclic aromatic hydrocarbon and polychlorinated biphenyl availability compared to the untreated controls. HOC availability in the sorbent-treated sediment slightly increased by sorbent removal and after one month of mixing in a slurry phase because the slowly-desorbing HOC fraction was released and repartitioned back to the sediment, partially replenishing the rapidly-desorbing HOC fraction. However, HOC availability did not further increase during an extended mixing period of 12 months suggesting that the repartitioning process was not an infinite source. HOC availability after the 12-month post-treatment mixing for the sorbent-treated sediment was 53-97% lower than that of the untreated sediment because of the combined effect of HOC mass removal from sediment (with the sorbent) and incomplete recovery of available HOC fraction in the sorbent-treated sediment.
原位添加到沉积物中用于封存疏水性有机污染物（HOCs）的吸附剂，可能会因施加在沉积物表面的水动力而被从处理地点冲走。本研究的目的是检验在完全去除吸附剂后，吸附剂改性沉积物中HOC有效性恢复的可能性。在水相悬浮液中，沉积物与易于分离的模型吸附剂Tenax珠粒接触28天，与未处理的对照相比，多环芳烃和多氯联苯的有效性降低了74-98%。吸附剂处理过的沉积物中HOC的有效性在去除吸附剂后以及在水相悬浮液中混合一个月后略有增加，因为缓慢解吸的HOC部分被释放并重新分配回沉积物中，部分补充了快速解吸的HOC部分。然而，在长达12个月的延长混合期内，HOC的有效性没有进一步增加，这表明重新分配过程不是一个无限的来源。由于从沉积物中（与吸附剂一起）去除HOC质量以及吸附剂处理过的沉积物中可用HOC部分的不完全恢复的综合作用，吸附剂处理过的沉积物在处理后12个月混合后的HOC有效性比未处理的沉积物低53-97%。
