Comment submitted by Tennessee Department of Environment and Conservation (TDEC) and Tennessee Department of Health (TDH)

Summary: The Tennessee Department of Environment and Conservation (TDEC) and the Tennessee Department of Health (TDH) support the retention of the current Maximum Contaminant Level (MCL) and Maximum Contaminant Level Goal (MCLG) of 10.0 ppt for PFHxS. They argue that recent sampling data shows detections exceeding this level in some Tennessee water systems and emphasize that PFHxS poses significant health risks due to its biopersistence and toxicity.