Why Boiling alone does not make water fully safe for drinking?

Boiling kills bacteria and viruses but does not remove harmful dissolved impurities such as Pesticides, Rust, Heavy Metals, Arsenic, Fluoride etc. Just as we cannot remove dissolved salts from water by boiling, similarly we cannot remove dissolved impurities from water by boiling.

Presence of such impurities in water may cause serious diseases such as cholera, hepatitis A & B, jaundice, typhoid and even cancer.