If you add the valences of each atom in the molecular formula for arsenious acid, H 3 AsO 3, you can see that the molecule, which is uncharged, has a total valence state of 0 (3x(+1) for the hydrogen atoms; 1x(+3) for the arsenic(III) atom; 3x(-2) for the oxygen atoms = 3+3-6 = 0).
Eighty percent of sewage in India is untreated and flows directly into the nation's rivers, polluting the main sources of drinking water, a study by an environment watchdog showed Tuesday.
Sources of Drinking Water. In most cases, drinking water comes from two sources: surface water or ground water. Surface water sources are bodies of water on the earth's surface, such as rivers, lakes, and reservoirs. Ground water sources are underground aquifers which are geologic formations containing water underground.