Chelation therapy can be administered orally, intravenously, or intramuscularly, depending on the type and severity of the poisoning. Common chelating agents include EDTA (ethylenediaminetetraacetic acid), DMSA (dimercaptosuccinic acid), and DMPS (dimercaptopropane sulfonate). The choice of agent and route of administration will depend on various factors, including the specific heavy metal involved, age, and overall health of the child.