by Dan Falk
There’s an old saying that what goes up must come down – and in the case of dangerous chemical pollutants, knowing exactly where they come down, and in what concentration, is crucial.
Frank Wania, an environmental chemist at the University of Toronto Scarborough (UTSC), has made a career of studying these pollutants – where they come from, where they end up, and how they impact our environment and our health. And his research has received a major boost with funding for a new $1 million “clean lab” – virtually unique in Canada – scheduled to open at UTSC this coming fall.
Wania and his research team specialize in tracking “persistent organic pollutants,” compounds typically created in industrial processes or used as pesticides. Examples include PCBs (polychlorinated biphenyls) and brominated flame-retardants – a class of retardants added to many plastics and electronics such as computers and televisions.
Because these compounds resist degradation, they can build up in the environment and in organisms, which allows them to work their way through the food chain, a process known as “bio-accumulation.”
Once these pollutants start to bio-accumulate, Wania explains, they can pose a significant risk to human health. “Once they’re in the air, they go into the lakes; once they’re in the lakes, they accumulate in the food chain,” says Wania, a researcher in the Department of Physical and Environmental Sciences at UTSC.
Remarkably, the populations that face the greatest danger may live thousands of kilometres from where the chemicals originate. The pollutants can spread far and wide once they’re swept up in the atmosphere, absorbed into soil, or washed out into rivers and lakes. Wania and his team are particularly interested in the effects on remote areas: They’ve recently worked in mountainous areas in Central America, Africa, and Asia, as well as British Columbia. “It’s intriguing that some of these places, considered among the cleanest in the world, actually have contamination issues,” Wania says.
It turns out that many of these remote areas have remarkably “efficient” food chains – in other words, the more links in the food chain, the higher the potential for bioaccumulation. One example is the Canadian Arctic, home to the nation’s Inuit. What is special about the Inuit diet is that it comes at the end of a particularly long food chain (water; zooplankton; small fish; big fish; seal; human) compared to a typical southern diet: (air; grass; cow; human). The Inuit diet is rich in meat and fish; those animals, in turn, are exposed to whatever chemicals may be present in the smaller fish that they consume. As the pollutants work their way up the food chain, the concentrations increase, and the potential health risk to the Inuit can be profound.
“It’s really counter-intuitive that the Inuit, living in remote areas, might be exposed to higher levels of contamination than we would be, in downtown Toronto,” Wania says. “So that makes it all the more important to understand how the chemicals get from where they’re being used to where they’re accumulating in the food chain.”
Wania has learned a great deal through his extensive field work, which has taken him from the rainforests of Costa Rica to the wetlands of the Okavango Delta in Botswana. Together with his graduate students, he collects air samples over many months, or even years, and brings them back to Toronto for analysis. Although this travel to exotic locations may sound appealing, Wania cautions that it can also be grueling, exhausting work. The trips can begin by automobile, but they sometimes end with the team journeying on foot, hiking up mountains or traveling on horseback to reach elusive research locations. “The logistics of these trips can be brutal,” he admits.
Just as important as the field work are the sophisticated computer models that Wania develops in an effort to understand the way these organic pollutants become dispersed around the globe. The models focus primarily on the atmospheric transport of the chemicals – the crucial first step in the chemical’s entry into the food chain.
This dispersion can be complicated by numerous factors. Because many chemical processes are temperature-dependent, certain chemicals enter the atmosphere – and are deposited into soil and water – at rates that vary depending on the climate.
Contaminant levels can also vary across a particular landscape. In mountainous areas, Wania found that the higher the elevation, the higher the concentration of certain compounds. He saw this effect first hand in Costa Rica: Pesticides containing persistent organic pollutants are used on the country’s banana plantations, which lie close to sea level. But the pesticide actually turns up in higher concentrations on the tops of mountains, many miles away. Wania believes he knows why this happens: It’s warmer in the valleys, where some of the chemicals are in the gaseous phase. As they get lifted up the mountain by air currents, they cool. At these lower temperatures, they attach themselves to water droplets, and can be more readily distributed when it rains, ending up in the soil, and in the food chain.
The effect may explain the decline in certain amphibian populations in the mountains of Central America – with animals that live at higher altitudes more severely affected. For instance, the Golden Toad of Costa Rica “sort of disappeared from one year to the next, and people are trying to find out why. The current understanding is that the cause is a pathogen, in combination with climate change. Some of these amphibian extinctions tend to occur at high altitudes, further removed from human activities, which is the opposite of what you might expect.” Wania’s team found pesticides inside the water collected in bromeliads -- a family of flowering plants in which some amphibians breed -- in a remote mountain location in Costa Rica.
Closer to home, Wania and his team are striving to reach a more complete understanding of the chemicals themselves – a venture that will take advantage of the new UTSC clean lab opening in September. The lab is called ALFONSE – a somewhat clunky acronym for “Advanced Laboratory for Fluorinated and Other New Substances in the Environment” and will be located in SW-436 in the Science Wing. The lab will be the only one of its kind in the country, Wania says, for although there is a similar facility in Burlington, ALFONSE will feature a series of filters that block out possible trace gases and particles to an extreme degree, ensuring quality results by removing even the smallest contamination that might in any way taint the specimens inside the lab. Reserachers from Environment Canada and the Ministry of Natural Resources will also be using the lab.
Professor Scott Mabury, an environmental chemist on the St. George campus and the University of Toronto’s vice-provost (academic operations), is the principal investigator on the $1.7 million grant, which is supporting $1 million for the construction of the ALFONSE lab with the remainder directed to equipment purchase at both the UTSC and St. George campuses. Wania’s research is also supported by funds from the United Nations Environmental Program (UNEP), the Natural Sciences and Engineering Council of Canada (NSERC), the Canadian Foundation for Climate and Atmospheric Sciences (CFCAS), and CEFIC, the European Chemical Industry Council. Funding for the new lab comes primarily from the Canadian Foundation for Innovation, with matching funds from the province and from the university.
Pinning down the precise properties of different organic pollutants is a critical step in the effort to monitor their dispersion and their impact. Chemicals with certain properties are more likely to reach, say, the Canadian Arctic, and possibly accumulate there. Research to be centered in the new lab will help pinpoint those compounds that pose the greatest risk. Industry can then adapt by instituting new practices to restrict the use of certain compounds. As well, regulatory agreements, such as the Stockholm Convention on Persistent Organic Pollutants, can be amended to reflect newly-recognized dangers. (The Convention took effect in 2004, with the first amendments added last year.)
Currently the Canadian government is required to assess the human and environmental risk of tens of thousands of commercial chemicals, and one way to make that task easier would be to compare the properties of those chemicals with the properties revealed to be problematic by Wania’s research. “We need to find out which, of a very large number of compounds, we need to worry about,” says Wania. “Which ones are likely to be the most troublesome? This research could help to determine sooner and more efficiently which chemicals need additional attention by regulators and to help prioritize that list.”
Professor Don Cormack, chair of the department of physical and environmental sciences, says these studies work have many implications. “The research being conducted by Frank Wania and his team at the University of Toronto Scarborough is answering important environmental questions that are influencing government policies worldwide. This important research on the transport and fate of environmental pollutants is of concern to everyone on the planet as we continue to grapple with issues related to the impact of human activities on the environment and on human health.”
The possibility that his work might make a difference in the way chemicals are regulated around the world gives Wania great satisfaction. “Of course,” he adds, “there is also a real thrill in scientific discovery.”