PAH Repartitioning in Field-Contaminated Sediment Following Removal of the Labile Chemical Fraction
PAH Repartitioning in Field-Contaminated Sediment Following Removal of the Labile Chemical Fraction
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DOI：
10.1021/es9016798
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发表时间：
2009-11-01
影响因子：
11.4
通讯作者：
Thibodeaux, Louis J.
中科院分区：
文献类型：
--
作者：
Birdwell, Justin E.;Thibodeaux, Louis J.
在现场污染的沉积物中考察了去除与沉积物颗粒相关的不稳定化学部分，然后进行内部化学再分配的效果。利用解吸平衡(有机碳-水分配系数，K-OC)和动力学(释放速率)实验数据，估算了不稳定和非不稳定化学组分或有机质隔层的多环芳烃两相分配和解吸速率。去除不稳定的化学成分后，沉积物的K-OC值增加了50%到150%。在解吸实验中耗尽不稳定的化学部分后，将沉淀物储存30和90天，以允许在不稳定和不稳定的隔室之间进行化学再分配。随后的解吸数据表明，随着不稳定的化学部分重新进入不稳定的隔室，发生了重新分配。这些结果提供了证据，证明有机质隔间之间的化学转移，无论是通过颗粒间孔隙水还是通过直接的颗粒内隔间交换，是一种真实的现象，发生的时间相对较短(几周到几个月)。这对以下观点提出了质疑：非活性化学部分中的疏水有机污染物长期被隔离或生物可利用性较低，并对受污染沉积物再悬浮事件期间的水质影响、受污染场地的风险评估和沉积物修复策略的选择产生影响。
The effect of removing the labile chemical fraction associated with sediment particles followed by internal chemical redistribution was examined in a field-contaminated sediment. Using data from desorption equilibrium (organic carbon-water partition coefficients, K-OC) and kinetic (rate of release) experiments, estimates of polynuclear aromatic hydrocarbon biphasic partitioning and desorption rates for both the labile and nonlabile chemical fractions or organic matter compartments were obtained. Sediment K-OC values increased between 50 and 150% after removal of the labile chemical fraction. Following depletion of the labile chemical fraction during desorption experiments, sediment was stored 30 and 90 days to allow for chemical redistribution between the labile and nonlabile compartments. The subsequent desorption data indicated repartitioning had occurred with the nonlabile chemical fraction recharging the labile compartment. The results provide evidence that chemical transfer between organic matter compartments, either through interparticle porewater or via direct intraparticle compartmental exchange, is a real phenomenon that occurs over relatively short times (weeks to months). This calls into question the idea that hydrophobic organic pollutants in the nonlabile chemical fraction are sequestered or less bioavailable over the long-term and has implications for water quality impacts during contaminated sediment resuspension events, risk assessment of polluted sites, and selection of sediment remediation strategies.