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Sustainable Development

Soils study predicts limited risks to community

The following is an interview with Chris Wren, director of the Sudbury Area Risk Assessment (SARA) Group, an affiliation of companies and experts contracted to carry out the Sudbury Soils Study, a seven-year $12 million study to determine if the level of metals in the study area environment pose a risk to humans, plants or animals.SMSJ: What is the background of the Sudbury Soils Study?

Chris Wren: The Ontario Ministry of the Environment (MOE) undertook a review of information on metal levels in the soil in Sudbury and, not surprisingly, the concentration of metals was higher than the generic soil quality guidelines. The MOE issued a report in 2001 and made two recommendations. First, they recommended a more detailed survey to fill in data gaps for metal distribution in the Sudbury area and, secondly, that a human health and ecological risk assessment should be conducted. Inco and Falconbridge agreed to the recommendations and put together a partnership to oversee the studies. That evolved into a technical committee that included Inco, Falconbridge, the Ministry of the Environment, the Sudbury and District Health Unit, the City and a representative from Health Canada.

In 2001 and 2002, soil samples were collected from thousands of locations around the Sudbury area. The samples were analyzed and the risk assessment began in 2003.

SMSJ: How does this study compare with similar studies that have been done? How unique was it?

CW: It’s a very unique study. It’s one of the largest studies of its kind ever conducted in Canada and I think it will be viewed as a real landmark, even worldwide.

SMSJ: What was the objective of the Human Health Risk Assessment?

CW: For the Human Health Risk Assessment, we set out to determine if there is a potential risk to human health as a result of the metals in the environment in Sudbury. We collected samples of drinking water. We had a one-year air monitoring program. We collected vegetables from more than 70 gardens. We collected indoor dust from homes and schools. We put all of the resulting data into a very detailed exposure model and calculated the dose for a person living in Sudbury.

SMSJ: What results did you come up with?

CW: Overall, the results were very promising. There were six chemicals of concern: arsenic, cobalt, copper, nickel, lead and selenium. For four of these chemicals of concern, we predicted no risk. For two – lead and nickel – we predicted some limited risk. We concluded there was a potential risk to toddlers and children aged six months to five years from lead in the soil in specific locations. That doesn’t mean people should go out and remove the soil from their yards. That’s one option if they really want to, but there are other means to mitigate or reduce exposure.

Soil is only a relatively small component of the exposure to lead in Sudbury. Probably over half of the lead that people are exposed to comes from supermarket foods, so whether you live in Sudbury or Toronto, you’re getting the same exposures. Some of the lead comes from the smelters, but a lot of it comes from other sources, including old paint. Lead levels in the soil in Sudbury are not alarmingly high – no higher than what you’d find in older neighbourhoods in other cities in Ontario.

SMSJ: What about nickel?

CW: For nickel, there are two exposure routes. For ingestion, we predicted no risk. However, for inhalation, there are some forms of nickel that are carcinogenic and there were elevated levels of these forms of nickel in a couple of the air monitors around Sudbury. These were related to the Inco facilities in Copper Cliff, so when we add up the exposure over a lifetime, there could be a potential risk for lung and throat inflammation and respiratory cancers. Having said that, the Medical Officer of Health says that the incidence of lung cancer in Sudbury is no different than it is in the rest of northeastern Ontario.

SMSJ: Apparently there is a higher incidence of lung cancer in Northern Ontario, but it’s usually attributable to a higher incidence of smoking.

CW: That’s correct, but the risk assessment is very conservative, so we flag it as a potential risk and that allows Vale Inco to do something about it. It’s interesting to note that the nickel is not coming out of the Superstack itself. It’s nickel in dust form low-level sources – dust off roads or waste rock piles. It’s what we call fugitive emissions.

SMSJ: What did the ecological risk assessment focus on?

CW: We went out into the ecosystem and we looked at vegetation types and vegetation communities. We did soil toxicity testing to determine if the soil was allowing or inhibiting recovery. The Sudbury area has been impacted by historical exposure. Since the 1970s, the city has undertaken an extensive regreening program. They’ve done amazing work, but there are still a lot of areas that need attention – areas where trees have been planted and they’re growing, but maybe not as well as they could be, or it’s not a diverse ecosystem.

We attempted to determine what may be inhibiting recovery and what treatment methods could be pursued to promote the regreening of the landscape.

We also looked at wildlife. We picked valued ecosystem components like moose, fox and different bird species. We looked at the concentration of metals in the environment where these animals are living. Generally, the levels are much lower than in the city. For most animals, we predicted no risk.

SMSJ: Looking at some of the statistics published comparing metal concentrations in Sudbury and other Ontario communities, it appears that metal concentrations are significantly higher in Sudbury.

CW: Yes, but elevated concentrations don’t translate into risks. Just because the metals are in the soil doesn’t mean that they’re getting into people’s bodies.

SMSJ: What about arsenic?

CW: In 2004, the Medical Officer of Health issued an advisory, warning people in Falconbridge to take precautions against elevated arsenic levels. The people in the community were alarmed, so to address their concerns, we did an arsenic exposure study. We measured the arsenic levels in people’s urine in Falconbrdige and Hanmer. We sampled 350 people in each community, so it was a huge study. Arsenic levels in the soil in Falconbridge are about 20 times higher than in Hanmer (a Sudbury area community at a greater distance from the smelter), but the arsenic levels in people’s urine in both communities were virtually identical.

SMSJ: The process established for the study was quite unique, wasn’t it?

CW: We had a technical committee and an independent process observer. There was some skepticism within the community and the unions because the companies were at the table and funding the work. People thought they would control the results. Scientists rely on scientific information and results, but we understand how people can be skeptical, so we had a lot of checks and balances. The Ministry of the Environment and the Health Unit were at the table, so they looked at all of the data and a toxicologist hired by the technical committee reviewed all of our work.
The process observer was invited to all of our meetings, so he could sit there and see how decisions were made. Then, we had external peer reviewers in the U.S., including some scientists affiliated with the Environmental Protection Agency, who reviewed our work, so it was a very rigourous process. We also had a public advisory committee and public meetings to keep the public informed about the study.

SMSJ: Was it an effective process?

CW: On paper it works. In reality, it was quite frustrating because it’s like getting everyone in the family to agree on what to have for dinner.

SMSJ: If a study such as this were conducted again, what changes would you recommend?

CW: There are different aspects of the process model that could be examined – funding, for one. If some of the other stakeholders had a commitment for some of the funding, they might be a little less flippant about requesting certain studies or doing additional work.

SMSJ: The study didn’t focus on occupational risks, did it?

CW: No, and that’s been a source of controversy for a segment of the population. The unions and some ex-union members are disappointed that the study didn’t address occupational exposure, but the study never set out to address occupational exposure. It’s covered and addressed by each of the companies, along with the Ministry of Labour and the unions. We think we’ve done a more stringent study. No one has ever looked at the risk to the average resident or the toddler, so we think we’ve done the community a great service by focusing on the health of people living in the Sudbury area.

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