Project Summary (2011-2017)

Remediation of highly contaminated Superfund sites requires monitoring and evaluation of the contaminants themselves and their byproducts. Superfund sites have diverse and complex toxic species that contaminate soils, water and the surrounding air. Determining what is there, and then determining the extent and effectiveness of remediation continue to present challenges. The rapid development of nanotechnology has offered significant opportunities to produce new sensors for the characterization and monitoring needs of Superfund, not only in the gas phase, but in the different environments where toxic and/or hazardous materials are produced or where they accumulate.

Drs. Yang and Koshland are taking advantage of the unique properties of nanoscale materials to detect and measure species such as heavy metals. They are developing a collection of sensing protocols for the detection of arsenic, mercury and flame retardant compounds with high sensitivity and specificity. The researchers are developing and applying small-molecule chemical indicators for fluorescence detection of mercury, lead, cadmium, and other toxic heavy metals in environmental laboratory and field samples, with specific interest in seafood and soil specimens. Parallel with this effort, plasmon absorption spectroscopies based on metal nanocrystals are being used for low-cost, rapid detection of mercury in air and aqueous environmental samples. The researchers are continuing to develop silver nanocrystal based substrates for ultra-sensitive arsenic detection using surface enhanced Raman spectroscopy. They are extending this sensing platform towards detecting chemical fingerprint for the analytes, distinguishing between the two most common oxidation states of arsenic: arsenate (As^V) and arsenite (As^III), both in ground water and some other complex media. Similarly this sensing scheme is being applied towards detection of methylated arsenic species with high sensitivity using small sample volumes. In addition, the researchers also are developing a sensitive and selective miniaturized electronic sensor for environmental toxicants molecules such as polybrominated diphenylethers (PBDE) using specific molecular recognition elements. These studies should provide new methods to detect and measure chemical and biological species at Superfund sites. The new methods will be useful for assessing remediation efforts and the reduction of hazardous species at known sources.