You say you live in an apartment....so I take it that you rent? I'd take this to the landlord, because it sounds like you really need to get it replaced. It could be mold, or who knows what. If he refuses, you can contact the EPA and find out who locally can look into environmental health issues. The not knowing is not good, and I'd be especially afraid of having my child on such an odd thing. This is the landlord's responsibility for carpet and pad replacement, and possibly even remediation of the flooring underneath.