Sure, Peggy, the 2006 NRC Committee recommended that the current MCL for fluoride should be lowered.  The sole reasons cited for this were risk of severe dental fluorosis, bone fracture, and skeletal fluorosis, with chronic ingestion of fluoride at a level of 4.0 ppm or greater.  It made no recommendation to lower the secondary MCL of 2.0 ppm.

a.  Severe dental fluorosis is rare in the US and, as noted by this same committee, does not occur in communities with a water fluoride content of 2.0 ppm, or less.  

b.  Risk of bone fracture is a U shaped curve with the greatest chance at too little or too much fluoride.  The least risk is at the optimal level.  

c.  Skeletal fluorosis is so rare in the US as to be nearly non-existent.  

As nearly 75% of the US is fluoridated at 0.7 ppm, lowering the MCL to a level between 2.0 and 4.0 ppm is a moot point.

FSA does not exist at the tap in fluoridated water. It is not ingested.  There is no need to test it for safety.

Steven D. Slott, DDS