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.
Pollution of the Ganges, the largest river in India, poses significant threats to human health and the larger environment. Severely polluted with human waste and industrial contaminants, the river provides water to about 40% of India's population across 11 states, serving an estimated population of 500 million people or more, more than any other river in the world. Today, Ganges is considered to be the fifth most polluted river in the world. Raghubir Singh has noted that no one in India spoke of the Ganges as polluted until the late 1970s.