Many elements and compounds naturally reside in the ground that are harmful to humans when ingested at elevated concentrations. Under certain situations, these contaminants can become suspended in water and can contaminate the groundwater that is often pumped to the surface for human consumption. Drinking water sources can also become contaminated from discharges from factories and other polluters. Lastly, water resources can become contaminated with bacterias, viruses, and pathogens from sources like human and animal waste if they are not adequately protected. These three issues pose environmental challenges in every country, but in the developing world, the financial and technical resources may not be available to readily deal with them.