Main Sources of Arsenic are given below:
1. Natural rocks and soils
2. Agricultural industry (chemicals like As203, lead arsenate, etc.)
3. Fungicides, pesticides and herbicides
4. Mining and extraction
5. Glass industry
In the earth's crust, the level of arsenic is 2 ppm (the main one being sulphide). The main sources of arsenic pollution are agricultural chemicals. Arsenic can exist in two forms-trivalent and pentavalent. Trivalent arsenic is the most toxic one.
The toxic action of arsenic is due to its affinity towards sulphur. It thus, attacks the sulphydryl (-SH) group of an enzyme, inhibiting its enzyme activity essential for the generation of cellular energy in the citric acid cycle.
Thus, pyruvate-oxidase system becomes less effective in generation of main energy source, i.e., adenosine triphosphate (ATP) due to its complexation with arsenic.
Some biochemical processes involving phosphorous are also hampered due to the interference of arsenic because of its chemical similarity to phosphorous, preventing ATP generation. Arsenic (III) compounds coagulate protein at higher concentration levels.
One of the major contributions of arsenic pollution is contamination of ground water. Contamination of ground water has become a global phenomenon.
If arsenic polluted water is used for drinking and cooking purposes for a prolonged time, a person may suffer from anaemia, melanosis, keratosis and conjunctivitis.