Ake C L, Wiles M C, Huebner H J, McDonald T J, Cosgriff D, Richardson M B, Donnelly K C, Phillips T D
Intercollegiate Faculty of Toxicology, Department of Veterinary Anatomy and Public Health, College of Veterinary Medicine, Texas A&M University, College Station 77843-4458, USA.
Chemosphere. 2003 Jun;51(9):835-44. doi: 10.1016/S0045-6535(03)00040-7.
Complex mixtures of hazardous chemicals such as polycyclic aromatic hydrocarbons (PAHs) in contaminated soil and groundwater can have severe and long-lasting effects on health. The evidence that these contaminants can cause adverse health effects in animals and humans is rapidly expanding. The frequent and wide-spread occurrence of PAHs in groundwater makes appropriate intervention strategies for their remediation highly desirable. The core objective of this research was to assess the ability of a clay-based composite to sorb and remove toxic contaminants from groundwater at a wood-preserving chemical waste site. Treatment efficiencies were evaluated using either effluent from an oil-water separator (OWS) or a bioreactor (B2). The effluent water from these units was passed through fixed bed columns containing either an organoclay composite or granular activated carbon. The sorbent columns were placed in-line using existing sampling ports at the effluent of the OWS or B2. Individual one-liter samples of treated and untreated effluent were collected in Kimax bottles over the course of 78 h (total of 50 samples). Subsequently each sample was extracted by solid phase extraction methodology, and pentachlorophenol (PCP) and PAH concentrations were quantitated via GC/MS. Columns containing porous organoclay composite, i.e. sand-immobilized cetylpyridinium-exchanged low-pH montmorillonite clay (CP/LPHM), were shown to reduce the contaminant load from the OWS effluent stream by 97%. The concentrations of benzo[a]pyrene (BaP) and PCP were considerably reduced (i.e. >99%). An effluent stream from the bioreactor was also filtered through columns packed with composite or an equivalent amount of GAC. Although the composite reduced the majority of contaminants (including BaP and PCP), it was less effective in diminishing the levels of lower ring versus higher ring PAHs. Conversely, GAC was more effective in removing the lower ring PAHs, except for naphthalene and PCP. The effectiveness of sorption of PCP from the OWS effluent by the composite was confirmed using a PCP-sensitive adult hydra bioassay previously described in our laboratory. The findings of this initial study have delineated differences between CP/LPHM and GAC for groundwater remediation, and suggest that GAC (instead of sand) as the solid support for organoclay may be more effective for the treatment of contaminated groundwater under field conditions than GAC or CP/LPHM alone. Further work is ongoing to confirm this conclusion.
污染土壤和地下水中的多环芳烃（PAHs）等有害化学物质的复杂混合物会对健康产生严重且持久的影响。这些污染物会对动物和人类造成不良健康影响的证据正在迅速增加。PAHs在地下水中频繁且广泛地出现，因此非常需要针对其修复的适当干预策略。本研究的核心目标是评估一种粘土基复合材料在一个木材防腐化学废物场地吸附和去除地下水中有毒污染物的能力。使用油水分离器（OWS）或生物反应器（B2）的流出物评估处理效率。这些装置的流出水通过装有有机粘土复合材料或颗粒活性炭的固定床柱。吸附剂柱利用OWS或B2流出物处现有的采样口串联放置。在78小时内（共50个样品），在Kimax瓶中收集处理过和未处理的流出物的单个一升样品。随后，每个样品通过固相萃取方法进行萃取，并通过气相色谱/质谱法对五氯苯酚（PCP）和PAH浓度进行定量。含有多孔有机粘土复合材料的柱，即沙子固定的十六烷基吡啶交换的低pH蒙脱石粘土（CP/LPHM），显示可将OWS流出物流中的污染物负荷降低97%。苯并[a]芘（BaP）和PCP的浓度大幅降低（即>99%）。生物反应器的流出物也通过装有复合材料或等量GAC的柱进行过滤。尽管该复合材料减少了大多数污染物（包括BaP和PCP），但在降低低环PAHs与高环PAHs的水平方面效果较差。相反，GAC在去除低环PAHs方面更有效，但萘和PCP除外。使用我们实验室先前描述的对PCP敏感的成年水螅生物测定法，证实了该复合材料对OWS流出物中PCP的吸附效果。这项初步研究的结果描述了CP/LPHM和GAC在地下水修复方面的差异，并表明作为有机粘土固体载体的GAC（而非沙子）在现场条件下处理受污染地下水可能比单独使用GAC或CP/LPHM更有效。正在进行进一步的工作以证实这一结论。
