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.
Water pollution is the contamination of water bodies (e.g. lakes, rivers, oceans, and groundwater). Water pollution is a major problem in the global context. It has been suggested that it is the leading worldwide cause of deaths and diseases and that it accounts for the deaths of more than 14,000 people daily.