WHAT ARE THEY?
Nitrates are inorganic chemical compounds derived from nitrogen, (NO3-) that are found naturally in small concentrations in soil, food, and surface and groundwater.
HOW DOES NITRATE POLLUTION OCCUR IN WATER?
The increased concentration of this compound in water occurs primarily in areas of high agricultural production due to the massive use of nitrogen fertilizers, historically applied in greater quantities than crops can absorb.
It should also be noted that wastewater discharges and animal excrement in areas of intensive livestock farming can also constitute a source of nitrates in the water.
WHAT ARE THE LIMITS SET FOR THE PRESENCE OF NITRATES IN DRINKING WATER?
The WHO has determined, based on numerous scientific studies, that high concentrations of this compound in drinking water pose a danger to human health.
The regulations that establish the health quality criteria for drinking water in Spain are Royal Decree 140/2003, which sets the maximum permitted concentration of nitrates in drinking water at 50 mg/l.
HOW CAN HIGH CONCENTRATIONS OF NITRATES IN WATER BE PREVENTED?
Whenever possible, water sources used for supply are those that meet the concentration limits established by current legislation. However, there are areas where this is not possible due to the widespread presence of high nitrate concentrations in the groundwater and/or surface water. In these cases, secondary treatment, permitted by the health authority, is carried out to reduce the nitrate concentration in the water supply to below 50 mg/l.
