Micro-fluidic spectrometer for measuring groundwater contamination

Past industrial practices have resulted in groundwater that is contaminated by heavy metals. Long-term monitoring and maintenance is one of the largest costs of environmental management. This project is developing a compact analyzer for measuring chromium ions in ground water that should significantly reduce the cost of monitoring the presence of this metal. The Phase I project investigated a novel detection strategy that allows sensitive measurement using a micro-cavity. The sensitivity demonstrated in Phase I was comparable to the levels found in drinking water, fully demonstrating the analytical precision of this approach. The Phase II research will address ways to minimize interference from other chemical species, build the optical, electronic, and sample-handling subsystems, assemble a hand-held analyzer, and characterize it in the laboratory and in the field. Measurements at the well head will be compared to results from the existing approach, which is to send sample bottles to a lab for analysis. Ultimately an automated version of the system will be placed in the well itself, so that the labor cost of going to the well also is eliminated. Measurements at the well head should eliminate the ongoing cost of mailing and analyzing samples, and should improve decision making and measurement quality by eliminating the four to five day wait between sampling and measurement results. Commercial Applications and Other Benefits: A compact sensor for chromium pollution would have applications in waste water treatment, groundwater monitoring, and in public water works. The sensing concept could be extended to measure other compounds.