EEOS Professor Refines High-Tech Tools to Study Coastal Pollutants
By Peter Grennen of The University Reporter (March 2007)
Almost daily, there are reports of new concerns about the impact of human activity on our natural environment. UMass Boston professor Gordon Wallace was recently awarded a $300,000 grant from the Cooperative Institute for Coastal and Estuarine Environmental Technology (CICEET) to improve how researchers evaluate the effect of metal pollutants that wash into estuaries and other coastal bodies of water, particularly those in urban and industrial locations.
A partnership of the National Oceanic and Atmospheric Administration and the University of New Hampshire, the institute promotes the health of coastal regions nationwide by developing high-tech tools that can test the contaminant levels of water systems. Wallace's research, which began in the fall, has seen him work in close cooperation with investigators from the National Estuarine Research Reserve (NERR) facilities located in Waquoit Bay, Massachusetts, and Wells, Maine. UMass Boston doctoral student Franco Pala has also conducted key research in the technology's development.
The project addresses a major concern of environmentalists: the impact of human activity in littoral areas--in particular, the continual washing of metal pollutants into estuaries and other coastal bodies of water. "Habitat quality and ecosystem functioning are subject to change by a wide variety of natural and anthropogenic perturbations, the latter of which are particularly prevalent in coastal regimes adjacent to major population centers," said Wallace, a professor in the Environmental, Earth and Ocean Sciences Department.
The mere presence of metals in these waters is not necessarily cause for concern, Wallace pointed out. Rather, the toxicity of the metals depends on their "bioavailability": Dissolved metals that bind to organic matter are much less bioavailable--and therefore less toxic--than those that exist as free ions. "Free ions are the key to understanding many of the reactions of metals in the environment--where the metal goes, what form it's in, and how much is available to interact with the activity of organisms," Wallace explains.
Determining the physical state of metal contaminants is therefore a prerequisite to designing a strategy for remedying the problem--but current methods for making such determinations are far from ideal. "Because of the importance of metal-free ion activities to chemical and biological processes that affect biological activity, the ability to quickly make sensitive and precise measurements in these environments is needed," says Wallace. "However, measurement of free-ion activities is currently limited to time-consuming, technically difficult procedures, many of which suffer from uncertainties in their interpretation."
Still, Wallace and his research team believe there is no need to develop from scratch a technology that avoids these pitfalls. They are hoping to further refine an existing CICEET project probe called VIPER (Vibrating Ion Probe Equilibrium Recorder), which measures free-ion concentrations of copper and lead in marine environments. Their focus will be on improving the instrument's sensitivity and accuracy, reducing analysis time, and developing a trace metal-free prototype for use in a variety of aquatic environments.
Thus far the researchers' results have been nothing short of spectacular. "This is the quickest and simplest way at this time to make low-level measurements of copper and lead," said Wallace. The new probe is so sensitive it can detect about one-tenth of a trillionth of a gram in one liter of water.
Wallace said that over time such precision will gain his sensor a central, permanent role--and greatly expand usefulness--in the scientific monitoring of water systems. "Eventually, such a probe may be capable of integration into in situ instrumentation in coastal observatories with results provided remotely to shore-based stations," he said.