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.
Oil spills are also another source of water pollution, even on land since it can contaminate water via run off or by seeping into the ground, polluting ground water. Soil Pollution: Like air and water, the soil itself can also become polluted from dangerous materials such as heavy metals, pesticides, and landfills.