A community residing in a flood-prone district uses contaminated groundwater containing high levels of fluoride (7 ppm). The permissible limit of fluoride in drinking water as per BIS/Indian standards is 1.0 mg/L (1 ppm), and the maximum permissible in absence of alternative is 1.5 mg/L. Long-term consumption above 3–6 ppm causes skeletal fluorosis. Which other element in Indian groundwater, especially in Indo-Gangetic plains, co-occurs geochemically with fluoride and also causes chronic toxicity?
- A Chloride
- B Selenium
- C Copper
- D Arsenic ✓
Explanation
Arsenic contamination of groundwater is a major problem in the Indo-Gangetic plains of India (particularly West Bengal, Bihar, Assam, Uttar Pradesh) where geogenic arsenic is leached from alluvial sediments under reducing conditions. Fluoride contamination co-occurs in parts of Rajasthan, Gujarat, Telangana, and other arid belt states, while arsenic predominates in the Gangetic belt. India's permissible arsenic limit in drinking water is 0.01 mg/L (WHO guideline), though many groundwater sources in affected districts far exceed this. Chronic arsenic exposure causes arsenicosis — including Mees' lines, keratosis, Bowen's disease, and cancers of skin, lung, and bladder.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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