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MONITORING WASTE IN GROUNDWATER (WITHOUT ALL THE WASTE)Harth, R. University of Arizona Biodesign Institute News Release, Mar 2011
Under a new 3-year, $1.15 million grant from DoD, Rolf Halden, assistant
director at Arizona State University's Swette Center for Environmental
Biotechnology, is pursuing a novel method to conduct groundwater sampling and
monitoring. His team's efforts are part of a quest to provide more accurate
results at lower cost and produce fewer by-products during the sampling
process. Conventional monitoring typically accounts for at least 20% of total
cleanup costs incurred during site remediation. To minimize the waste-handling
and associated costs associated with conventional sampling, Halden's sampling
technique involves acquiring groundwater as it remains in place in the
subsurface using a device known as the in situ sampler, or IS2. Custom fitted
to the groundwater monitoring well, the IS2 is deployed downhole, where its
integrated pumps draw up ambient groundwater at milliliter-per-day rates.
Analytes of interest are concentrated onto solid adsorption media for
analysis. One of the advantages of the in situ approach is that effluent from
the device remains in the subsurface. Only the device itself with the
extracted analytes is removed from the well. In this way, monitoring can be
conducted without the use of purge water or the liberation of wastewater at
the surface. Once the device has been removed from the well, the
contaminant-charged media are shipped to the laboratory, where they undergo
automated analysis assisted by robotics, as well as standard methods including
mass spectrometry and ion chromatography. The new technology boasts extremely
low detection limits--in the ng/L to pg/L range. Further, it produces no
wastewater and can be carried out at a low cost per sample, thanks to the use
of automation. The IS2 sentinel will be applied on a pilot basis at DoD sites
and used in multiple deployments to examine a range of groundwater
contaminants, such as VOCs (PCE and TCE), water-soluble fuel components
(benzene and toluene), explosives constituents (RDX and TNT), semivolatiles
(phenol), PAHs (naphthalene and phenanthrene), inorganics (perchlorate), and
heavy metals (arsenic and lead). Each of these analytes will be captured in
situ, using a pair of customized IS2 devices. Results will be compared to
those obtained with conventional water monitoring approaches. The project
seeks to demonstrate improved detection limits 10 to 100 times lower than
those achieved through current EPA methods. The accuracy, reproducibility, and
precision of results could also exceed EPA methods, providing detailed
analyses of a broad spectrum of compounds at considerably lower costs. While
initial efforts focus on monitoring at DoD hazardous waste sites, the
technology ultimately should find broad applicability for groundwater
oversight.
http://www.biodesign.asu.edu/news/monitoring-waste-in-groundwater-without-all -
the-waste
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