10.  In Situ Biotransformation of Contaminants in Sediments

Challenges to sediment remediation include not only the sheer scope of contamination but also technical limitations and escalating costs associated with cleanup. The development of in situ sediment remediation technologies, mirroring the development of successful in situ groundwater remediation approaches, has recently been identified as a priority research need (SERDP and ESTCP, 2004) and could result in treatments that are more effective compared to traditional methods. Implementation of technically feasible and cost-efficient in situ remediation approaches, such as in situ biotransformation, provides numerous potential advantages which could contribute to successful contaminated sediment management. Most notably, in situ biotransformation can directly reduce contaminant concentrations and/or toxicity. When occurring naturally, in situ biotransformations could serve as a key component for management strategies based on monitored natural recovery (MNR) and could potentially be incorporated into capping and combined remedy designs. In other scenarios, engineering may be required to stimulate particular microbial populations and/or manipulate environmental conditions to optimize biotransformation (and biodegradation) activity.