Troubled Water

When it comes to cleaning up America’s waterways, Dominic Di Toro likes to point out, most of the obvious fixes already have been implemented. Constructing wastewater treatment plants and installing more stringent industrial emission controls, for example, have proved effective ways to enhance water quality.

“The bad news is that, now that the easy things have been done, attacking the remaining problems requires more difficult and more expensive solutions,” Di Toro says.

The Edward C. Davis Professor of Civil and Environmental Engineering is internationally known for his leading-edge work in the development of methods to establish water quality criteria and the development of water quality models. His work has been recognized by the prestigious National Academy of Engineering, which recently named him one of its 74 new U.S. members.           

Academy membership honors those who have made outstanding contributions to engineering research, practice or education. It recognizes scientists who have been pioneers in new and developing fields of technology, made major advancements in traditional fields of engineering or developed innovative approaches to engineering education.

Di Toro was selected because of his leadership in the development and application of mathematical models for establishing water quality criteria and making management decisions.

Di Toro describes himself as both “flattered and gratified” by his election to the academy. “I am pleased to have the respect and appreciation of my peers,” he says.

Di Toro has managed or directed water quality studies of some of America’s most important bodies of water, including New York, Boston and Milwaukee harbors, the Delaware, Ohio, Sacramento and Potomac rivers and the Chesapeake and San Francisco bays.

He has developed mathematical models of chemicals that are discharged into bodies of water, tracking where the chemicals go and how they behave, and has done important work in developing water and sediment quality criteria to determine how much of a given chemical would impair the aquatic health of a water body.

Di Toro says his work is done collaboratively, which he adds is characteristic of modern environmental engineering. “The problems we are dealing with are too complicated for one person or one discipline,” he says. “Water quality problems must be attacked using multiple disciplines—biology, toxicology and chemistry, as well as engineering—to create successful and useful models.”

In a new interdisciplinary project at UD, Di Toro is collaborating with Timothy Targett, professor of marine biology and biochemistry in the College of Marine Studies, to research how fish react to reduced oxygen levels in water. Such drops in dissolved oxygen can occur when nutrients are discharged into a body of water, leading to algae growth and low oxygen, or hypoxia. Targett has studied the effects of hypoxia on various species of fish.

With the joint project, Di Toro says, the researchers hope to quantify the problem of hypoxia by establishing criteria for dangerous levels. “How much is too much? How little is too little? Those are some of the hardest questions to answer in dealing with environmental issues,” Di Toro says.

In general, he says, researchers try to answer those questions by studying the organisms that are most sensitive to pollutants and setting water-quality criteria to protect them. If those creatures are protected, the reasoning goes, then almost all other organisms will be safe as well.

Over the years, information based on Di Toro’s work has been the basis of governmental regulations and in some cases now is standard practice in the water quality industry. Models he developed were used to set the standards in a treaty between the United States and Canada regulating phosphorous discharges in Lake Erie and Lake Ontario. 

Lake Erie, which by the late 1960s was so polluted by industrial discharge and poorly treated sewage that many of its important fish species had died out, is considered a key environmental success story. With clean water regulations and advances in fighting pollution, the lake and its fish have made a well-publicized turnaround.

Today, Di Toro says, the Chesapeake Bay is facing some of the same types of problems that once plagued Lake Erie.

Di Toro, who joined the UD faculty in 2003, is the author of the well-received book Sediment Flux Modeling.

At UD, he says, the Department of Civil and Environmental Engineering faculty is marked by an atmosphere of professional collegiality and encompasses the disciplines necessary to address present and future areas of research and environmental practice.

“That’s important because environmental engineering is a broad and relatively young discipline,” Di Toro says. “We’re a field that’s still evolving, and there is plenty of opportunity for important and interesting work to be done.”