The "travellers" are of no concern. 

EPA mandated  Standard 60 requires that no contaminant be present in water at the tap in excess of 10% of the EPA MCL for that contaminant.  In order to even detect any contaminants, whatsoever, in water fluoridated with HFA requires 10 times the normal amount of HFA.  Under stringent NSF testing of this water, arsenic is detected in less than 50% of random samples.  In these samples, the maximum amount of arsenic detected is only 0.6 ppb.  The EPA MCL for arsenic is 10 ppb.  Thus the maximum allowable under Standard 60 is 1.0 ppb. 

Lead is detected in less than 1% of random samples, with the maximum detected being 0.088 ppb.  The maximum allowable under Std 60 is 1.5 ppb.  

Obviously, neither arsenic nor lead is  of any concern in fluoridated water. Any other detected contaminants are in even more negligible amounts than arsenic and lead.

Steven D. Slott, DDS