Salt is hatvested from salt lakes around the world. As far as any single lake goes, you would be best advised to ask local agencies about it. No way we have any information regarding unsafe things which have occurred on a single lake. The lake waters may have been diverted for agriculture, or local mines could have let runoff taint the water. Just too many possibilities to advise you properly. I mention only those two possibilities but there are others like bacteria and pollutants... local water testing agencies would probably know.