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ESTCP DEMONSTRATION OF A BIOAVAILABLE FERRIC IRON TEST KIT
Citation:
Evans, P., C. Lebron, J T. Wilson*, R. Chappell, AND R. Olsen. ESTCP DEMONSTRATION OF A BIOAVAILABLE FERRIC IRON TEST KIT. SERDP/ESTCP The Partners In Environmental Technology Technical Symposium and Workshop, Washington, DC, November 30 - December 02, 2004. SERDP, Arlington, VA, 1, (2005).
Impact/Purpose:
xxxxxhttp://www.stormingmedia.us/61/6175/A617534.html The objective is to allow remedial project managers to determine whether sufficient assimilative capacity is available for continued contaminant transformation.
Description:
Bioavailable ferric iron (BAFeIII) is used by iron-reducing bacteria as an electron acceptor during the oxidation of various organic contaminants such as vinyl chloride and benzene. Quantification of BAFeIII is important with respect to characterizing candidate natural attenuation sites because it allows remedial project managers to determine whether sufficient assimilative capacity is available for continued contaminant transformation. Measurement of dissolved ferrous iron in groundwater samples gives no indication of this future assimilative capacity.
An off-the-shelf BAFeIII test kit demonstrated and validated at multiple sites under the Environmental Security Technology Certification Program. This test kit is a bioassay that uses iron-reducing bacteria and allows direct measurement of BAFeIII in soil samples. Soil samples from the multiple sites were analyzed using the test kit and results were compared to other analyses conducted on the samples. These analyses included selective chemical extraction for iron and sulfur species, microcosms for measurement of biological iron reduction, and electron microprobe analysis for mineral speciation.
Results indicated that the test kit is precise and more robust than other available methods for BAFeIII quantification. Additionally, the data showed positive associations between test kit results and factors that are known to affect iron bioavailability such as oxide crystallinity and surface area. These results will be presented along with practical implications and applications of the BAFeIII test.