Mississauga is hiring a forensic consultant to track down more than a dozen sites across southern Ontario that may have received arsenic- and lead-contaminated dirt swept from the city’s streets.

Ontario’s Ministry of the Environment has accused the city of inadequate testing before sending its street sweepings as free sandy fill to an estimated 47 sites, including a campground and several farms.

The province ordered the city in November to test or even dig up thousands of tonnes of street grit. Mississauga, however, is appealing that directive, arguing that the material does not pose a risk and removing it could cost tens of millions of taxpayers’ dollars.

At one property in Cayuga, Ont., that received roughly 1,000 tonnes of Mississauga’s street sweepings, multiple test samples contained lead or arsenic, “all of which were at levels which could present an unacceptable risk to human health due to direct contact exposures,” a Ministry of the Environment report said.

Meanwhile, the province said it does not even know the address for 15 of the sites where the material was sent. City records provided to the province show only that hundreds of loads of street sweepings were delivered to recipients such as “Private Landowner,” “Newfie” or somewhere in Acton.

The consultant’s forensic audit will “identify and gather information in relation to (these) previously unassessed sites,” a ministry spokesman said, adding that the two sides agreed to a “revised timeline” for the work to be done during a conference call last Wednesday with Ontario’s Environmental Review Tribunal.

The audit’s findings must be shared with the ministry and public health officials.

Neither Mississauga nor the province said specifically when the forensic report will be complete.

The city says the landowners were told of the origin of the street sweepings and provided with the results of its testing.

“There is no risk to human health or the environment from the materials delivered” to the Cayuga site, Mississauga’s lawyer said in a 2016 corporate report.

“With respect to the remaining sites, based on a preliminary risk evaluation, the city expert’s opinion is that the risk to human health or the environment from the materials is unlikely.”

In its ongoing appeal, Mississauga also argued that the ministry’s order against the city could irreparably harm its reputation for environmental excellence.

Mississauga used to ship the dirt its road sweepers collected to be used as landfill cover. But in 2004, the city started storing the sweepings — a blend of sand, gravel and grit — in its Mavis Rd. work yard, where it would be screened for debris and chemically tested by an external consultant.

At a landowner’s request, the city would deliver the material free to be used in private construction projects. From 2004 to 2011, Mississauga shipped hundreds of loads across southern Ontario.

That stopped in 2012 after the ministry raised concerns. According to a 2016 report by the ministry, tests were then done at two “sensitive” sites: the one in Cayuga and a property in Selkirk, off Lake Erie. Samples found electrical conductivity “measured at levels that could present an unacceptable risk to plants and soil organisms,” the report said.

A woman reached at the Cayuga location on Saturday said “no comment” before hanging up the phone.

Provincial inspectors visited other sites and found seven landowners who said they didn’t understand the material was street sweepings, the ministry report said. Two residents claimed that they found debris in the fill.

Paul Galvin, whose Olympia Village RV Park and Campground in Waterdown received numerous loads of fill from Mississauga, said the material he got was like topsoil and is “all clean.”

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“(The ministry) took their own samples and I have a letter from them giving me a clean bill of health,” he said, adding that his own monitoring wells for his on-site sewage system have not detected any problems.

“If anything was going to show up, it would have shown up a long time ago,” he said.

For now, none of the controversial fill will be dug up. The ministry said it has taken mitigation measures to protect the health of property owners while it continues its investigations.

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