Nitrate and Nitrite
Overview
Nitrate and nitrite are water-soluble forms of nitrogen commonly found in the environment. Nitrate is naturally produced through the decomposition of organic matter and is also introduced through fertilizers, sewage, and animal waste. It can enter both surface water and groundwater through runoff and leaching.
Health Implications
High nitrate levels in drinking water pose a health risk, especially to infants. In the body, nitrate can convert to nitrite, which interferes with oxygen transport in the blood, potentially causing methemoglobinemia (blue baby syndrome). Regulatory limits are:
• Nitrate: 50 mg/L
• Nitrite: 0.5 mg/L
Anyone concerned about these compounds in the drinking water should contact their local authority or health board for further advice.
Treatment Methods
• Reverse Osmosis (RO): Uses a semi-permeable membrane to remove nitrates; suitable for household use.
• Ion Exchange: Swaps nitrate ions with chloride or sulphate; requires regular maintenance.
• Distillation: Effective but energy-intensive and less practical for home use.
• Electrodialysis: Uses electrical currents to separate nitrates from water.
Important Considerations
• Boiling: Increases nitrate concentration and should be avoided.
• Infant Safety: Use ready-diluted formula and consider bottled or mains water for babies under 6 months.
• Testing: Regular testing is essential to detect nitrate levels and identify contamination sources.