Novel Uses for Environmental Sensors: Towards a Mode of Action Sensor Array for Arsenic

The research group NUES (Novel Uses for Environmental Sensors) at Virginia Tech is working to develop novel mode of action sensor arrays that are capable of continuous monitoring of soluble species in water, the bioavailable fraction of the species, as well as the geochemical conditions that influence the species' mobility and its effects on biological communities.

We are currently assembling four individual sensors, including a Corbicula fluminea (Asian clam) sensor, a bacterial potassium efflux assay sensor, a fluorescent E. coli sensor, and an electrochemical sensor array (Hydrolab DataSonde) to create this mode of action sensor array for arsenic (As) in natural waters. The Corbicula sensor determines the amount of As within the system that can be bioaccumulated into tissue. This sensor has been laboratory tested for As tolerance, bioaccumulation, and viability in various aquatic environments. The potassium efflux assay monitors the adverse biological (oxidative) stress elicited by As. Although it has not been used before with As, previous work shows that an oxidative stress can be elicited via exposure to cadmium. The fluorescent E. coli sensor, developed at the University of Lausanne, determines the total amount of bioavailable As present in the water. We are currently applying this sensor to a microfluidics chip, which would allow for field deployment. The Hydrolab DataSonde collects data on field parameters including pH, dissolved oxygen, temperature, conductivity, and water level, which will yield a geochemical “fingerprint” for the environment in which As occurs.

Some of the insights we wish to glean from this research include how changes in geochemical conditions can affect arsenic bioavailability, whether arsenic bioavailability differs in soil water, groundwater, hyporheic water, and stream water, and if arsenic bioavailability varies depending upon arsenic source or land use type.