Depending on where you are located, "play sand" composition could vary widely. There is no assurance your play sand and Dustin's play sand come from the same source. One might be ok to use and the other not.
My favorite sand is pool filter sand which is silica sand. It's available from pool supply concerns.
The sterility of sand is not the issue. Sterllizing sand will not affect the mineral content. I rinse all my silica sand until the water runs crystal clear, which removes a lot of other powdered mineral contaminents, dust, etc that have accumulated in the silica. Rinsing sand with other mineral inclusions present other than silica quartz will not be effective, since the mineral present in the mixed sand can leach into the substrate, if they are present, over time.
Effects might not immediately show, but long term health problems could arise as the leaching process progresses over time. The high natural acidity of peat will result in the formation of salts as the acids react with the mineral inclusions which accumulate and concentrate in the mix through evaporation over time. What starts out good may not stay good.
On the other hand, it could all work out, your sand might be just fine: there really is no way to say for sure. Cautious experiment is recommended, but the better advise is to test your sand. The presence of carbonates (i.e. lime) is especially bad for most CP, and this mineral presence can be detected with a drop of strong acid which will make the sand fizz. It is possible some pharmacist would be willing to assist you in this if asked. Quartz will not fizz.
The safest quartz sand is uniformly white, and granular like sugar. Tan and multicolored sand are probably suspect, as is any sand with bits of shell in it, or sand which is in any way muddy or very dust laden.
That's my rationale. I hope this helps.