Here are direct links to the primary sources mentioned. Four scientific studies, an EPA health advisory, and a report from a non-profit organization.

[1] https://doi.org/10.1186/s12940-023-00997-6

[2] https://doi.org/10.1080/1547691X.2023.2176953

[3] https://doi.org/10.1021/acs.est.2c02765

[4] https://doi.org/10.5334/aogh.4013

[5] https://www.epa.gov/sdwa/drinking-water-health-advisories-pf...

[6] https://chemsec.org/reports/the-top-12-pfas-producers-in-the...