Toronto zoos have a bad track record with keeping elephants well and alive for normal lifespan ever since I can remember.
Toronto has been fluoridated since the early 1960s. The outer suburbs started buying prefluoridated water supply from Toronto in the early seventies yet many suburban dentists still thought they were seeing patients who didn’t have access to fluoridated water, so thousands of kids were taking fluoride drops and tablets too. The rate of moderate fluorosis in the teeth of those kids is appalling.
The fluoride concentration was rarely below 1.2 mg/L and occasionally over 2 mg/L or even 3 mg/L until the late 1990s when Hardy Limeback and John Yiamouiyannis went before city council and blew the whistle on child overdose effects.
The zoo went through a series of elephant exhibits but of course the public never knew about the problems until the internet. Toronto started lowering the fluoride level below 1 ppm after Hardy went public and gave that landmark apology speech to his graduating class of dental students.
By 2006 or 2007 it was .6 ppm with fewer overfeeds.
The first Toronto zoo was downtown and elephants were basically in a concrete cage. Part of the problem may have been dry food diet – in the wild they get fresh live forage that would have provided a good part of their fluid intake depending on season. Also I cannot remember if the zoo had Indian or African elephants, and I know these are different species with differing abilities to tolerate cold, drought etc.
And OF COURSE you can’t find anything that indicates these zoo animals can’t tolerate 1 ppm! NO RESEARCH HAS BEEN DONE ON NORTH AMERICAN ZOO ANIMALS FOR IT!!!