Toxic wells. After listening to all the animals that can kill on the beach in Australia, I understand that quiea not go to the beach. Some people may think that a hole or lake, pond. Anyway, swimming is a safe alternative. Freshwater wells are often toxic and are infested with parasites and diseases. One of the most popular diseases is amoebic meningitis. It is lethal with a survival rate of less than 3 percent.