Sustainabilitylive! 2012 Seminar Programme - Early Site closeout using Biotraps and DNA analysis - a case study.

Molecular biological tools (MBTs) are a cost effective and expedient mechanism of understanding the likelihood of natural micro fauna in delivering a more expedient and sustainable clean up solution. Typically assessing the feasibility of natural attenuation focuses upon the assessment of decay products and often misleading environmental chemistry and plate counts. Field environmental chemistry suffers from reporting issues and is an indirect indicator only. Instead specialist sample gathering devices can cost effectively be deployed within boreholes for subsequent microbial testing. These can assist in facilitating a greater understanding of microbial populations in-situ and the effectiveness of microbial degradation in reducing the residual contaminant mass. By way of example WSP have recently delivered Light Non Aqueous Phase Liquid (LNAPL) recovery works from groundwaters beneath a site in Perthshire Scotland. Investigation identified elevated concentrations of petroleum hydrocarbons up to 10,000mg/kg within soils. Physical recovery works have since delivered significant betterment. MBTs have also been deployed so as to lend support and comfort that any residual mass is reducing and risk projections are negligible to surrounding surface waters. Specifically Quantitative Polymerase Chain Reaction (qPCR) has been employed in combination with Stable Isotope Probing (SIP). Using these MBTs then costs and delivery close out was reduced by 18 months to regulatory satisfaction. WSP will present an overview of MBT tools followed by way of example the advantages and lessons learned.