1) The concentration of fluoride, lead, nitrate, and iron in a water sample from an underground lake was found to be 1000 ppb, 40 ppb, 100 ppm, and 0.2 ppm, respectively. This water is unsuitable for drinking due to the high concentration of A) lead B) nitrate C) iron D) fluroide Answer: Option BExplanation: This water is unsuitable for drinking due to the high concentration of nitrate. In drinking water. the maximum permissible concentration of $lead \simeq 50 ppb$ $nitrate\simeq 50ppb$ $iron \simeq 0.2ppm$ $fluroide\simeq 1 ppm$
