Previous Year Question

Groundwater Pollution occurs when the concentration of harmful chemical substances, microorganisms, or other contaminants increases in groundwater, affecting its quality. Water pollutants are generally classified into Biological and Abiotic/Inorganic categories. Arsenic (As) is a toxic Metalloid that occurs in groundwater as an inorganic chemical pollutant. It is naturally present in the Earth's crust and can dissolve into groundwater from rocks and minerals.

Arsenic in groundwater primarily occurs in the forms of Arsenite (As III) and Arsenate (As V). Arsenic present in rocks and sediments may be released into groundwater through Geochemical Processes. Additionally, certain industrial activities, mining, and the use of arsenic-containing chemicals can contribute to contamination. In India, arsenic contamination of groundwater has been reported in parts of several states, including West Bengal, Bihar, Uttar Pradesh, Assam, and Jharkhand.

Long-term consumption of arsenic-contaminated water can cause chronic arsenic poisoning known as Arsenicosis. Major health effects include dark patches on the skin (Hyperpigmentation), thickening of the skin on the palms and soles (Hyperkeratosis), and an increased risk of cancers of the skin, lungs, and urinary bladder. The World Health Organization (WHO) has established a provisional guideline value of 0.01 milligrams per litre (10 micrograms per litre) for arsenic in drinking water. Treatment methods for contaminated water include Sorption, Chemical Precipitation, and appropriate Filtration Technologies.

Among the other options, Bacteria, Algae, and Viruses are associated with pollutants of biological origin. Bacteria are unicellular microorganisms, some species of which cause waterborne diseases. Algae are photosynthetic organisms whose excessive growth can affect water quality. Viruses are acellular infectious agents capable of transmitting various diseases through contaminated water. In contrast, arsenic is neither an organism nor an infectious agent but a chemical element. Therefore, among the given options, arsenic is an inorganic pollutant.