I don't know of any specific risks of using sand in your substrate, however, I will say this. If you are going to use a commercially available product labeled "PLAY SAND" rinse the hell out of it. By that I mean, when you are done, rinse it several more times. Several years ago we were setting up an aquarium with some rare Tropheus. We used a commercial play sand. We rinsed it in the tank, but only enough that it ran clear. The fish all promptly died overnight after having been doing well in our quarantine system for several weeks. It turns out the sand had something added to it, I forget the name, that was a mold, bacterial, fungus inhibitor. This was to retard said organism's growth in a sandbox.
Personally I wouldn't do it. Search this site or google ABG (Atlanta Botanical Gardens) Soil mix. This stuff works great. As long as it is well drained, ie over a false bottom or hydroton, it shouldn't smell like anything other than good soil.