Water contaminated with nitrates is extremely dangerous for children, especially for children in the first months of life. Nitrates themselves are low-toxic, but in the body under the influence of intestinal microflora they are reduced to nitrites, which are even more toxic. One of the main mechanisms of their toxic effect is the conversion of hemoglobin into methemoglobin.
Nitrates are a permanent component of natural waters. According to state and European standards, the concentration of nitrates in drinking water should not exceed:
- Ukraine: tap and well water – ≤ 50.0 mg/dm3, packaged – ≤ 10 (50) mg/dm3;
- EU: 45 mg/l.
The concentration of nitrates (nitrogen compounds) is influenced by many factors. They enter the water with runoff from fields treated with nitrate fertilizers or through discharges of waste water. Currently, the water quality is affected by the situation associated with military operations. In the post-war period, especially in liberated territories, the situation may still be unsatisfactory.
Consequences of high nitrate concentrations in water
Methemoglobin in the blood normally amounts to 2% of total hemoglobin. Depending on the level of methemoglobin, mild (10%), moderate (up to 40%), and severe (up to 60%) poisoning is distinguished. In children, a methemoglobin level of 5% can cause mild poisoning, and 40-45% can cause fatal consequences.
In Ukraine, there are also groundwaters where the Maximum Permissible Concentration (MPC) of nitrates can exceed the regulatory values by about 20 times, such as in certain areas of the Odessa region, Poltava region, etc. Epidemiological studies have revealed a direct relationship between the concentration of nitrates in drinking water and the incidence of atrophic gastritis and stomach cancer. Because nitrates in the stomach, under the influence of microorganisms, are reduced to nitrites, carcinogenic substances - nitrosamines, especially with reduced acidity.
Who is at risk?
The severity of nitrate poisoning depends on age. Children under 6 months are most sensitive to the effects of nitrates and nitrites, because the risk of developing methemoglobinemia in children of the first year of life is associated with the imperfection of the body's enzyme systems and biochemical processes. Such children consume 10 times more fluid per unit of body weight than adults.
Children under 3-6 years of age and pregnant women are also at risk. Elderly people, people suffering from anemia, people with diseases of the respiratory and cardiovascular systems, those with weakened bodies, metabolic and hormonal disorders, etc., are also sensitive to nitrates after consuming water with a high nitrate content.
Reasons for the presence of nitrates in water
One of the reasons for the presence of nitrates in wells and catchments is that their owners do not comply with the requirements of sanitary legislation when installing and maintaining wells, which leads to contamination of drinking water and makes it unsuitable for human consumption.
According to the requirements DSanPiN 2.2.4-171-10 «Hygienic requirements for drinking water intended for human consumption»", the Law of Ukraine "«About drinking water and drinking water supply», «On ensuring sanitary and epidemiological well-being» Responsibility for water quality and the condition of centralized and decentralized water supply sources in settlements lies with local governments and well owners.
Follow these rules to reduce the risk of nitrate exposure to your body:
- Do not drink water from wells and wells where the nitrate content exceeds the regulatory limit (50 mg/l). This is especially true for children and pregnant women;
- to prepare food or give it to a child under 3 years old to drink, use drinking water that is free of nitrates;
- The location of pump rooms, wells or springs should be located in an uncontaminated and protected area. This location should be located upstream of the groundwater at a distance of at least 30 m from highways with intensive traffic and at least 50 m (for individual wells - at least 20 m) from toilets, cesspools, sewage structures and networks, fertilizer and pesticide warehouses, livestock holding areas and other places of soil and groundwater contamination;
- Wells must be cleaned at least once a year: pump out the water, clean the walls with metal brushes from plaque and the bottom from sediment, unnecessary things that could accidentally get into the well, with subsequent disinfection. After that, the water must be pumped out again and the well must be used only after the next filling and laboratory testing of drinking water;
- The area near the well, spring catchment or pump room must be kept clean and surface runoff must be drained; within a radius of 50 m from pump rooms, wells and spring catchments, it is not allowed to wash cars, arrange animal watering places, water bodies for waterfowl, place devices for preparing pesticides and carry out other activities that may lead to soil and water pollution.
- It is also prohibited to arrange pump rooms, wells and spring catchments in places that are flooded, subject to erosion, landslides and other deformations, in low-lying and swampy areas.
- To insulate and protect wells and spring catchments from freezing, foam concrete, mats made of clean straw, hay, shavings, etc. can be used, but the specified material must not enter the water intake. It is forbidden to use manure, humus, etc. for this purpose.