Natural asbestos in Sumas River could be a health concern
There are fears asbestos-laced sediment deposited on the banks of the Sumas River could be stirred up by the wind or human activity and be inhaled.
Updated: January 13, 2019
A landslide in Washington state is causing elevated asbestos levels in an Abbotsford river that winds through some of B.C.’s best farmland.
Abbotsford Mayor Henry Braun said the Sumas River is used to irrigate large parts of the Sumas Prairie, where crops range from food and flowers to forage for dairy cows.
There are fears the asbestos-laced sediment deposited on the river’s banks could be stirred up by the wind or human activity and become airborne. Inhalation of asbestos fibres can cause cancer and chronic respiratory diseases.
“It’s an issue that keeps me awake at night,” said the mayor. “You can’t tell me that (the sediment) isn’t travelling. It could be drifting into the subdivisions on Sumas Mountain for all we know.”
The city plans to dredge the river in the coming year, something it does periodically to prevent flooding. The sediment is classified as hazardous waste and must be safely handled and disposed. In 2010 and 2011, the city spent $177,000 on cleanup and buried the material beneath heavy clay to prevent it from blowing away.
But the river also leaves sediment behind every time the water rises and falls.
After flooding in January 2009, American scientists found high levels of asbestos in soil along the Sumas River in the United States. Sampling done by the City of Abbotsford in 2009, and again in 2010, “confirmed contamination concerns,” according to an information bulletin released by the city the following year.
“These concerns go back three mayors,” said Braun, who wants the provincial and federal governments to find a solution.
But the source of the problem, like the source of the river, lies across the United States border.
In 1970s, a slow-moving landslide on Sumas Mountain in north Whatcom County began clogging Swift Creek with about 6,000 dump-truck loads, or 60,000 to 130,000 cubic yards, of sediment each year. After a particularly bad storm in December 2016, a Bellingham Herald story likened the flow to “a milkshake” that was “creamy-green in color.”
The sediment contains naturally-occurring asbestos, as well as heavy metals. Swift Creek flows into the Sumas River, which then follows a sinuous course for 24.8 river kilometres before crossing into Canada near Whatcom Road in Abbotsford.
From there, the river loops through the Sumas Prairie, where high-tech pumps move the water into a network of irrigation ditches used by farmers to water their fields, before crossing Highway 1. There are at least two popular dog-walking parks along the river, which is also used by kayakers and the Fraser Valley Water Ski Club in warmer months. It eventually flows through the Sumas First Nationbefore draining into the Fraser River.
Last year, after several attempts to address the problem, Whatcom County received funding from the state legislature to develop a plan to trap the sediment at the source, said Roland Middleton, a manager with the Whatcom County public works department. The project is expected to take six or seven years to complete.
“There’s actually not much asbestos in the landslide itself, but it concentrates in the water,” he explained. “The heavy materials settle, but the asbestos tends to float along.”
When asked if the sediment poses a significant health hazard, Middleton said a study conducted by the Washington state health department did not find an increased incidence of cancer among people living near Swift Creek. It did, however, determine there were unsafe asbestos levels in the air when the material was disturbed.
“We’ve tried to educate people who live along the flood plain so they’re not working in it, or breathing it in,” said Middleton. “Since people don’t do that, we haven’t seen a problem.”
In the past, the county has sent out flyers telling people to keep sediment wet or bury it, and to “not let your kids play out in the dust.”
At McDonald Park Friday, dogwalkers approached by Postmedia were surprised to hear the river contains asbestos and asked if they should prevent their dogs from swimming in it or rolling in the sandy areas along the shore.
Nearby resident Dorothy Balzer said she was aware the river contained asbestos and recalled when the city changed its dredging practices. From her living room, she can watch otters playing in the water and water-skiers practicing their barefoot skiing.
Abbotsford farmer Roy Schurmann said he’d heard the river sediment could contain asbestos, but he’s never thought much about it.
“I don’t really know the levels and what level would be harmful,” he said. “I’m a farmer, and I guess we don’t tend to worry about things like that.”
Before the city began disposing of the sediment as hazardous waste, Schurmann recalled spreading some on a low spot in his field. He also irrigates from the river.
Braun said Abbotsford has been asking the Ministry of Environment for assistance on the issue for almost 10 years, but has been told there is “insufficient” evidence of health risks.
The mayor said he was aware of the U.S. study that showed no rise in cancer rates, but he worried about the 20-to-50-year average latency period for asbestos-related cancer.
“Are we going to see farmers in that area developing cancer in the future?” he said.
The B.C. Ministry of Labour identified the naturally-occurring asbestos in the Sumas River as an issue in need of study in a recent report on asbestos.
The draft report noted “there are gaps in provincial and federal approaches to (naturally occurring asbestos) in the Sumas River, namely in identifying whether local workers and residents in the City of Abbotsford and Sumas First Nation are exposed. Activity-based sampling would provide valuable information to understand the potential inhalation exposure to (naturally-occurring asbestos) released from soil into the air through common activities.”
When asked if the provincial government had a plan to assess the health risks, the Ministry of Environment responded with a statement saying the province anticipates engaging with “U.S. state and federal agencies, Canadian federal government and City of Abbotsford to develop a path forward.”
Postmedia also asked if people who lived near the river had been made aware of the possible risk associated with disturbing sediment. In response, the ministry provided links to the City of Abbotsford information bulletin posted online in 2011, as well as an Abbotsford News article from the same year.
The Ministry of Environment also provided a copy of a 2010 report done during dredging of the river, which showed that air samples at that time were well within safe limits. However, the report noted some of the samples were taken on rainy days when moisture might prevent dust from becoming airborne. There was also no wind on several of the testing days.
Meanwhile, testing of the sediment itself showed unsafe levels of asbestos.
UBC land and food systems professor Hans Schreier said the health risks associated with the sediment are a “grey area.”
Scientists have shown the fibres change when they are submerged in water, but it is not clear if they remain carcinogenic. It’s also unclear how much exposure is hazardous.
“The United States Environmental Protection Agency has been trying to do an epidemiological study, but we don’t have the answers yet,” he said.