Nitrates in borehole water are almost always the result of farming on the land near the borehole.
There are both natural and man-made sources of nitrates in groundwater. The main source of nitrate contamination is invariably from agricultural operations, farm runoff and fertilizer usage.
Nitrates have no detectable color, taste or smell at the concentrations involved in drinking water supplies, and they do not cause discoloration of plumbing fixtures, so they remain undetectable to our senses.
Nitrates are converted by bacteria in the stomach of infants to toxic nitrites. At levels that would not cause harm to adults, nitrates can cause methemoglobinemia in infants, a condition also known as "blue baby" syndrome.
The EEC allowed maximum for nitrates is 50mg/l with an advised maximum of 25mg/l.
Nitrate dissolved within water will not be removed by simple filtration. It can only be reduced by either regenerative or throw-away cartridge type ion exchange techniques, or eliminated by Reverse Osmosis.
Is efficient, but will only work if the water is free of solid contaminants which can clog up the reverse osmosis membranes. Therefore before reverse osmosis can be used, the water must be cleared of all solids and particles.
Requires that chloride, i.e. brine solution be available to provide the chloride ions to be exchanged for the nitrate ions. In practical terms this means that the system must be regenerated by flushing with a brine solution at timed intervals and therefore, must be kept topped up with salt at regular intervals.