Playground sand or silica (the type of sand that should be used), has a whole lot of problems, and most playgrounds using it as a safety surface are not properly informed about the maintenance required. We have a playground sand page that goes into more detailed information, with comparisons and useful links. 

Sure sand is in a lot of playgrounds, there are also a lot of problems with it, and within it. Playground sand has to be installed and maintained at a 12" depth in any publicly accessible (non-residential) play areas. 

Perhaps the biggest problem is why it's recommended that playground sand only be used indoors, unless it can be under constant adult supervision to prevent any local pets, birds or feral animals from accessing it. Yep, many, if not most playgrounds with sand are just giant litter boxes. It's an act of futility raking out animal waste to stop the spread of zoonotic pathogens, diseases and parasites, because it doesn't work. There's no way you're getting all of it, and the pathogens get blending throughout the entire playground sand area. 

If you really feel you must provide sand for children to play in, make it a smaller sandbox that effectively contains all the sand. Cover it when when not in use to minimize contact with anything that could potentially get into it, and try to avoid it getting moist and warm. Heat, air and moisture are what microbes love best for spreading throughout the area.