The "Are the intake limits correct?" section (and the whole report, really) is fascinating and worth a read, but just to provide a concrete example of why federal limits might not be sufficient:
3M began producing PFOA (the most infamous "forever chemical") in 1947. It has been widely used in industry, and many millions of pounds of the stuff have been dumped into waterways since then. PFOA manufacturers were aware of some of the negative health effects of the substance in lab animals in the 1960s. Researchers outside of corporate America began studying PFOA in the 1980s. In the early 2000s, PFOA exposure via drinking water began to get public attention due to a lawsuit against DuPont.
As far as I know, the US government had no recommended limit on PFOA exposure in drinking water between 1947 and 2009.
In 2009, EPA established provisional health advisories for PFOA at 400 ppt and for PFOS at 200 ppt.
In 2016, EPA set a lifetime health advisory of 70 ppt for PFOA and PFOS combined.
In 2022, EPA published interim lifetime health advisories of 0.004 ppt for PFOA and 0.02 ppt for PFOS.
In 2023, EPA proposed health-based maximum contaminant level goals (MCLGs) for PFOA and PFOS of 0 ppt.
A lot of these chemicals are newer and less well-studied than PFOA, and we may still be in the period where federal limits are hundreds or thousands of times higher than the true safe level.
3M began producing PFOA (the most infamous "forever chemical") in 1947. It has been widely used in industry, and many millions of pounds of the stuff have been dumped into waterways since then. PFOA manufacturers were aware of some of the negative health effects of the substance in lab animals in the 1960s. Researchers outside of corporate America began studying PFOA in the 1980s. In the early 2000s, PFOA exposure via drinking water began to get public attention due to a lawsuit against DuPont.
As far as I know, the US government had no recommended limit on PFOA exposure in drinking water between 1947 and 2009.
Since 2009, limits have become progressively stricter. (For the timeline below, I'm quoting https://www.nrdc.org/press-releases/epa-restricts-toxic-pfas... )
In 2009, EPA established provisional health advisories for PFOA at 400 ppt and for PFOS at 200 ppt.
In 2016, EPA set a lifetime health advisory of 70 ppt for PFOA and PFOS combined.
In 2022, EPA published interim lifetime health advisories of 0.004 ppt for PFOA and 0.02 ppt for PFOS.
In 2023, EPA proposed health-based maximum contaminant level goals (MCLGs) for PFOA and PFOS of 0 ppt.
A lot of these chemicals are newer and less well-studied than PFOA, and we may still be in the period where federal limits are hundreds or thousands of times higher than the true safe level.