Natural remediation-bioavailability processes

Figure 1.14. Bioavailability processes in soils. Note the delineation of the entire scheme into natural remediation (left) and bioavailability (right). (Modified from the National Research Council, 2003 Adriano et al., 2004.)...

U.S. EPA defines MNA as the reliance on natural processes, within the context of a carefully controlled and monitored site cleanup approach, to achieve site-specific remediation objectives within a time frame that is reasonable compared to that offered by other more active methods. The natural processes include biodegradation, dispersion, dilution, sorption, volatilization, stabilization, and transformation. These processes reduce site risk by transforming contaminants to less toxic forms, reducing contaminant concentrations, and reducing contaminant mobility and bioavailability. Other terms for natural attenuation in the literature include intrinsic remediation, intrinsic bio-remediation, passive bioremediation natural recovery, and natural assimilation. 30... 

The ecotoxicological data reviewed in this section show that TNT contamination of soil can disrupt the ecological functioning of a soil system and inhibit natural attenuation processes. This occurs because TNT can destroy a portion of the soil microbial community involved in OM decomposition and reduces the amount of soil Corg produced by this community. Consequently, the amount of bioavailable TNT is relatively high and it interferes with colonization of impacted areas by plants, resulting in toxicity of TNT to soil invertebrates and adversely affecting site remediation and... 

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