AhR agonist and genotoxicant bioavailability in a PAH-contaminated soil undergoing biological treatment

Abstract

It has to be ensured that soft remediation methods like biodegradation or the natural remediation approach do not result in the mobilization of toxic compounds including more mobile degradation products. For PAH-contaminated sites this cannot be assured merely by monitoring the 16 target PAHs. The combined use of a battery of biotests for different types of PAH effects such as the CALUX and the Comet assay together with bioavailability extraction methods may be a useful screening tool of bioremediation processes of PAH-contaminated soil and contribute to a more accurate risk assessment. If the bioremediation causes a release of bound PAHs that are left undegraded in an easily extracted fraction, the soil may be more toxic to organisms living in the soil as a result of the treatment. A prolonged treatment time may be one way to reduce the risk of remaining mobile PAHs. In critical cases, the remediation concept might have to be changed to ex situ remediation methods.

Evaluation of hexachlorocyclohexane contamination from the last lindane production plant operating in India

“…Not only will the practical feasibility of these "soft" remediation methods need to be demonstrated but a thorough knowledge of degradation products and their toxicity is necessary (Weber et al 2008b;Andersson et al 2009). For example, the detection of several metabolites of HCH isomers (pentachlorocyclohexanols, pentachlorocyclohexenes and tetrachlorocyclohexane-diols) have been reported some of them with significantly higher water solubility and therefore mobility as compared to the parent HCHs (Raina et al 2007(Raina et al , 2008b.…”

Seasonal variation of HCH isomers in open soil and plant-rhizospheric soil system of a contaminated environment

“…It was recently demonstrated, e.g. for a PAH contaminated site, that the toxicity of the soil increased during bioremediation, although the target 16 EPA PAH had decreased (Andersson et al 2009). For HCHcontaminated sites, more water-soluble degradation products like chlorinated cyclohexenols and cyclohexenediols (Raina et al 2007(Raina et al , 2008 need to be taken into consideration.…”

Bioremediation of a Soil Industrially Contaminated by Wood Preservatives—Degradation of Polycyclic Aromatic Hydrocarbons and Monitoring of Coupled Arsenic Translocation

“…This suggests that the surfactant addition led to an overall increase in toxicity, either through the increased contaminant availability or through an inherent toxicity of the surfactant or a combination of both resulting in an interactive effect. Increased PAH availability as a result of bioremediation has been observed earlier (Andersson et al 2009). It is hypothesized that the degrading microorganisms utilize different methods to enhance the bioavailability in order to reach strongly sorbed compounds, but that the subsequent degradation has not taken place.…”