Nitrate compounds (water dissociable; reportable only when in aqueous solution)

Agricultural fertilizers and manure, septic/wastewater leaks, and certain industrial discharges; nitrate forms in water when these salts dissolve [1][2].

Mainly through drinking water (especially private wells); also some foods. Risk is highest when infant formula is mixed with high‑nitrate water [2][3].

High levels can reduce blood’s ability to carry oxygen (methemoglobinemia), especially in infants; long‑term intake under conditions that form nitrosamines has been linked to some cancers [2][5].

Infants under 6 months, pregnant people, people with certain enzyme or red‑blood cell conditions, and households using private wells in farm areas [2][3].

Test private wells yearly; treat water with reverse osmosis or ion exchange; use low‑nitrate or bottled water for infant formula if levels exceed 10 mg/L as nitrogen (EPA standard); do not boil water (it concentrates nitrate); maintain wells, septic systems, and careful fertilizer use [3][4].