One of two failed tests of fly ash taken from the scrubbers at Metro Vancouver’s incinerator in July found leachable cadmium levels at nearly six times the allowed limit.
The numbers were provided by Cache Creek Landfill operator Wastech Services and confirmed by Metro Vancouver, which previously had only said some ash tested at more than double B.C.’s limit for dumping as municipal waste.
The July results of monthly composite ash samples found 2.92 mg/L of leachable cadmium in one test and 1.85 in the other, compared to a limit of 0.5 mg/L after which the fly ash is considered hazardous waste. August samples measured 0.89 and less than 0.1 mg.
Incinerator operator Covanta Energy has apologized for being slow to turn over the test results – it only did so after Wastech asked for them in late September and after 1,800 tonnes of the over-limit ash had already been trucked to the landfill.
Metro now says older samples of incinerator fly ash dumped at the Cache Creek landfill’s special monofill cell around November 2010 also exceed the limit, prompting more extensive testing of all of the 25,000 tonnes of fly ash dumped there since mid-2010.
“At this point we don’t know what it means,” Metro solid waste manager Paul Henderson said.
He said three ash samples tested from the older area all exceeded the limit – despite having previously passed two types of tests done on ash at the Burnaby waste-to-energy plant before it’s trucked out.
Environment Minister Terry Lake formally launched an investigation Oct. 30 into the concerns around the fly ash transfers.
Any ash found to be hazardous at Cache Creek will have to be removed and sent to another facility, he said, because the landfill isn’t authorized to take hazardous waste.
Metro is sending new fly ash to an industrial landfill in Alberta since the summer test failures came to light.
“There is currently nothing to indicate any risk whatsoever to human health or environmental safety,” Lake said, but added any case of permit non-compliance must be taken “very seriously.”
Fraser Valley Regional District board chair Sharon Gaetz accused Lake of downplaying the health hazards.
She wants the investigation to go further and probe whether cadmium, a carcinogen tied to lung cancer, may have affected workers at the incinerator or landfill, or been spread into the Lower Mainland’s air.
“It is completely unacceptable that Covanta held back this information,” Gaetz said. “We are gambling with public health.”
Wastech general manager Janet Tecklenborg said landfill staff who deal with fly ash wear organic respirators and tie-back suits and a review has confirmed their procedures are correct.
“Our concern is the environmental risk to the community,” she said.
“We want to ensure we’re doing everything we can to protect the community, the safety of our employees and the land in the area.”
Tecklenborg said Wastech is very concerned that its compliance with regulations and relationship with the community was jeopardized when it unknowingly dumped the ash.
The fly ash is collected in fabric bags that keep it from going up the incinerator’s stack as air pollution.
A process using phosphoric acid and water then chemically binds metals like cadmium in the ash so it’s unleachable and can’t later be washed by rain into the environment after it’s landfilled.
According to Metro, the total amount of cadmium in the fly ash hasn’t changed, so either the treatment process didn’t adequately bind the cadmium – making it more susceptible to leaching – or else faulty tests incorrectly showed high levels.
Stack tests were done in July and August showed “excellent results” for air emissions, Henderson said.
The separate cell at the landfill is lined to keep any leachate that does develop from escaping to streams or groundwater.
“Our position has been from the beginning that, based on the information we have, there’s no potential impact on either the environment or human health as a result of the levels of cadmium being above the threshold,” Henderson said.
The landfill can’t dig up ash samples older than mid-2010 because the fly ash in those years was mixed in with municipal garbage. Prior to 2000, incinerator fly ash went to the since-closed Coquitlam landfill.