Amphibians absorb EVERYTHING through their skin, which is why it is so important to avoid handling them as much as possible, as well as to keep their environments free of contaminants and other possible threats. That being said, most terrestrial amphibians will make good use of a shallow water dish. I don't know anything about the Great Basin Spadefoot Toad however, so hopefully someone will be able to comment more on the specifics of that care