Do you mean a different article than that one? I couldn't find that reference to 2.7 anywhere (I even used search for 2.7 in case I missed it).
The article referenced above actually gives the previous article even less credibility as it was published in 1983 (so Cuba hotel swimmer was NOT the only case so far) and it also clearly states:
"Tooth enamel does not decalcify in acidic solutions unless the pH is below 6.0 (6). Even at a pH between 5 and 6, hours of cumulative exposure are required for clinically evident decalcification to occur (6)."
Cuba swimming lady swam for a couple weeks, a few hours a day and as she swam she got water in her mouth and spit it out. This says she would have had to soak her teeth in the pool water for hours on end to get clinically evident decalcification. Her teeth degraded a lot for the amount of time she swam in the untested pool. It was well beyond "clinically evident".
What's interesting about the second paper is that they at least went back and asked at the pool for records to try to figure out what happened. There were none really, and no one tested ph after the daily test showed "lower than 6.8" to verify that their additions had actually raised ph properly. There is no way to know what the ph of that pool's water actually was during the time of the tooth enamel issues (1982). There ARE a high number of cases reported from that same pool so it's evident that something was going wrong and that the ph was regularly found to be low when they opened and tested the pool for the day.
Edit: oops, the 2.7 reference was from the second link, not the first. But it still didn't reference a tested pool of 2.7, it just stated that pool water between ph of 2.7 and 7 that tooth enamel erosion is probable. The Thailand pools however... DID have low ph of 3.2something and 2.97 or something like that. How the heck does someone swim in that and not have skin irritation too?
Not arguing with the possibilities..., obviously low ph can cause enamel loss. I just didn't like the first paper. They didn't write a paper that had much basis, and that I could believe. That always makes me discount a paper's results. Studies should be based on facts, that one had very few actual facts.
