Nitrate nitrogen status in drinking water according to WHO is

Answer: Option A

Nitrate nitrogen status in drinking water according to WHO is 10mg/L.
The term “nitrate nitrogen” is used to refer to the nitrogen present which is combined in the nitrate ion.
Nitrates are essential to plant nutrients, but in excess amounts they can cause significant water quality problems, it can accelerate eutrophication and increases the risk of colon cancer. Drinking water with a nitrate level above 10 mg/L is unsafe.