NITRATE CONTAMINATION OF GROUND WATER IN THE NEEPAWA-LANGRUTH AREA OF MANITOBA

Abstract

Reports of methemoglobinemia of bottle-fed infants and nitrate poisoning of ruminants prompted an investigation of the cause and distribution of high levels of nitrate in ground water. The problem was found to be of common occurrence in areas where surface deposits consist of about 2 to 4 m of sandy-textured material overlying less permeable lacustrine clay or clay loam till. Although appreciable amounts of nitrate move to the ground water in fallow fields, a very high nitrate concentration occurs only in and around farmsteads or in the vicinity of towns and villages where human and animal wastes are concentrated. Ground water in the sites investigated moved laterally in a northeasterly direction, and a dilution of nitrate was observed in the slowly moving ground water to a level of less than 10 ppm within about 1/10 km in that direction. In contrast, ground water closely adjacent to the western and southern boundaries of the farmsteads, being up-grade from the source of contamination, was found to be free from toxic quantities of nitrate.