The sickening reality behind the Nitrates Directive
In Ireland, potable surface water is the main raw water source for drinking waters. Moreover, the quality of many of Ireland's amenity waters used for water abstraction and fishing has significantly deteriorated due to runoff from agriculture-related activities such as indiscriminate manure spreading on farm land.
Consuming small amounts of nitrate is not harmful. The problem arises in the case of infants of six months and younger (and also pregnant and nursing women) as they become susceptible to nitrate poisoning, because their undeveloped digestive tracts possess bacteria that convert nitrate into nitrite which is toxic.