How Safe is Our Water? Part Two
Rudolph says he laments that groundwater continues to receive little attention in comparison to the more visible surface water sources despite efforts of the University-based Waterloo Centre for Groundwater Research.
"There's hardly a nation on the planet that wastes more water than Canada because we have always had such an ample supply," he says. "But looking after our water has not been given a high priority."
Resourceful InnovationsCertainly, researchers at Waterloo are doing their share of work in water testing, treatment and remediation. It was there that Robert Gillham developed his reactive iron wall, a technology that has the potential of halving the cost of reducing the chlorinated solvents notorious as major industrial groundwater contaminants. The wall is a layer of granular iron and sand between layers of gravel, set vertically in the ground across the path of a plume of contaminated water. As water seeps through the wall, the solvents react with the iron and break down into elements and compounds harmless at normal concentrations.
Gillham says there now are 50 of these walls installed around the world.
Meanwhile, another kind of wall, also developed at the university, is being lauded for its ability to contain contamination. Dubbed the Waterloo Barrier, this impermeable wall was developed by earth sciences professor John Cherry and technician Sam Vales.
The barrier, which prevents contamination from escaping to surrounding areas, is now used by many research groups, and by landfills and industrial sites across the continent. It is expected to play a major role in attempts to clean up the United States' industrial and military waste sites in the next 30 years.
The work of other Waterloo researchers is not going unnoticed. Janusz Pawliszyn, a professor in the chemistry department, has commercialized a sampling technology called solid-phase microextraction (SPME).
Traditionally, environmental monitoring has involved sending chemists or technicians into the field to collect samples, bottles of water from lakes or soil from the ground. Back in the lab, they undergo a time-consuming and expensive process in which costly, high-purity and highly toxic solvents are used to extract contaminants.
SPME, on the other hand, involves use of a simple, low-cost syringe that can be inserted into a lake or stream or exposed to the air. The needle part of the adapted syringe is a tiny steel rod enclosing a glass fiber coated with a polymer to which pollutants chemically bond. The field worker pushes the plunger to move the glass fiber out of the steel needle and the pollutants bond with the polymer. The result is an on-the-spot analysis that discloses existing pollutants and their concentrations.
In another promising research initiative, Susan Andrews is studying effects of ultraviolet (UV) irradiation in the treatment of drinking water.
Since the mid-1970s, scientists have had concerns about the effects of chlorination, particularly when it reacts with organic matter to produce trihalomethanes, chemicals that may contribute to certain cancers. As a result, much of Andrews' work has focused on determining links between trihalomethanes and various health problems and to find ways to change treatment processes to reduce concentrations of these chemicals.
Andrews explains, "We can't just stop chlorinating altogether, but perhaps we can reduce the levels of chlorination needed to reduce the number of negative byproducts."
She says that, in time, many towns will be able to replace chlorination with UV irradiation in the beginning stages of disinfection. Chlorination would then only be necessary at the end of the process, in much smaller amounts.
While such research will ultimately have a significant impact in the ongoing battle against water contamination, the real key to a reliable supply of safe drinking water is increased vigilance and improved management that places a heavy emphasis on prevention, experts maintain.
This is part two of a three-part article. Reprinted with permission from the University of Waterloo Magazine, Fall 2000.