"There has been evidence for a few years that levels in the Great Lakes and St. Lawrence were higher than the national average, but not high enough to cause immediate alarm.
But what is considered safe is evolving, as research increasingly links forever chemicals to an array of potential health risks, such as cancer and reproductive issues.
Health Canada recently lowered the recommended drinking water limit for forever chemicals to a total sum of 30 nanograms per litre. A nanogram is one billionth of a gram.
The previous limits applied to just two types of the chemicals, allowing up to 600 ng/l of perfluorooctane sulfonate (PFOS) and up to 200 ng/l of perfluorooctanoic acid (PFOA).
That change has prompted calls for more oversight of forever chemicals in the Great Lakes, which supply drinking water to one-fifth of the Canadian population."
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