Organoclay adsorption of wood‐preserving waste from groundwater: Analytical and toxicological evaluations

Wood‐preserving waste is a complex mixture composed primarily of polycyclic aromatic hydrocarbons (PAHs) and pentachlorophenol (PCP), with trace concentrations of other halogenated aromatic hydrocarbons (HAHs). Although many of these compounds are slightly soluble in water, these substances have been detected in groundwater at high levels. Samples from the aquifers beneath a Superfund site in the northwestern United States were used to determine the efficacy of an organically modified clay adsorbent (CP/LPHM) for PAHs and PCP in the presence of background organics. Groundwater samples were treated with 0.5% (w/w) of CP/LPHM, and compared to samples which were not treated. Determination of the concentrations of the various PAHs was done by GC/MS. Naphthalene concentration, most abundant of all PAHs detected, was reduced by approximately 88% from 261 to 31 ug/ml of the extract. Other PAHs, many of which are known to be genotoxic such as benzo [a]pyrene, were also substantially reduced following treatment wi...