Quebec's public health institute (INSPQ) is proposing arsenic emissions in the air of Rouyn-Noranda be capped at an annual average of 15 nanograms per cubic metre (ng/m3), which is five times the provincial standard of 3 ng/m3.

A current agreement with the government allows Glencore's Horne smelter emissions to reach an annual average of 100 ng/m3 -- 33 times higher than the Quebec standard.

The new threshold would "solidly protect the health of unborn babies and young children," and reduce lung cancer risks for the population as a whole, said Quebec Public Health Director Dr. Luc Boileau.

"Achieving 15 ng/ m3 is an intermediate step towards reaching the standard," said an INSPQ scientific advisor at a technical briefing Wednesday, adding that "this value should be reached as soon as possible."

Speaking in Rouyn-Noranda Wednesday, Boileau did not comment on a possible timetable.

He said reaching this standard would require "substantial efforts that cannot be done in a few weeks or months."

Boileau said the 15 ng/m3 threshold "is a formal recommendation to the government," which must soon provide an updated arsenic emissions limit for the Horne smelter.

A MAXIMUM DAILY THRESHOLD

The INSPQ is also proposing a maximum daily arsenic threshold of 200 ng/m3.

A few weeks ago, an INSPQ report revealed that, over 70 years, an excess number of Rouyn-Noranda citizens -- between one and 14 -- would develop cancer if the smelter did not reduce the concentration of arsenic in the air.

With the new threshold proposed Wednesday, the risk of cancer would be "three cases per 100,000 inhabitants over 70 years" if the standard is respected for nickel and cadmium emissions. According to the INSPQ, the "unacceptable risk" corresponds to "10 cases per 100,000 inhabitants."

As there are about 40,000 inhabitants in Rouyn-Noranda, three cancers per 100,000 inhabitants represent 1.2 cancers over a 70-year exposure period.

In its conclusion of this new report, the INSPQ indicated that an annual average of 15 ng/m3 "will reduce the risk of lung cancer for future generations in the Notre-Dame district by a factor of about four compared to the current situation, a level considered acceptable in similar North American contexts."

The current exposure to arsenic and lead found in soils also poses a risk for young children. The INSPQ recommends "the addition of a maximum daily concentration of lead of 350 ng/m3," "the addition of a maximum daily concentration of cadmium of 30 ng/m3," and "the respect of annual standards for lead (100 ng/m3), cadmium (3.6 ng/m3) and nickel (20 ng/m3)."

On Monday evening, the Rouyn-Noranda municipal council unanimously adopted a resolution requesting that "the activities of the Horne smelter aim to achieve the environmental standards in force for all heavy metals and fine particles released into the air."

Teh resolution addressed to the Quebec government was in addition to another on June 13, which called for an interministerial action plan focused on the health of Rouyn-Noranda citizens.

The municipal council had also requested that the next ministerial authorization issued to Glencore by the Environment Ministry include daily emission ceilings.

TWO RECENT VISITS

This is Boileau's second visit to Rouyn-Noranda this summer. He held his first press briefing in the Abitibi-Témiscamingue city on July 6 as part of the presentation of another INSPQ study.

Both the smelter and the government agree that arsenic emissions must be reduced in the next agreement, but no exact threshold has been confirmed to date.

-- This report was first published in French by The Canadian Press on Aug. 10, 2022.