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.
Figure 1: Tap water supply, Nigeria Figure 2: Hand dug well water supply, Nigeria. Domestic Water Pollution among Local Communities in Nigeria ----Causes and Consequences 595 Figure 3: River water supply during dry season, Nigeria. 2. Causes of Water Pollution in Nigerian Communities 2.1.