ANALYSIS OF NITRATES AND NITRITES IN SUBSOIL AND GROUND WATER SAMPLES IN SWAZILAND

Abstract

The concentrations of nitrate as nitrogen (NO₃–N) in mg/L and nitrite as nitrogen (NO₂–N) in µg/L were determined in water samples from 60 boreholes, 21 shallow wells and 7 springs located in the four regions of the country. For all the 88 sampling points nitrate levels vary within 0.05 ± 0.00 – 28.44 ± 0.80 mg/L NO₃–N, out of which 10.22% have mg/L NO₃–N ≥ MCL (maximum contaminant level) of 10 mg/L NO₃–N. Shallow wells recorded the highest NO₃–N% ≥ MCL of 20.0% followed by boreholes with NO₃–N % ≥ MCL of 8.33% while for springs, the NO₃–N % ≥ MCL was zero. On the other hand, NO₂–N (µg/L) from all the sampling points vary within (ND/0.30 ± 0.00 – 297.0 ± 0.50) µg/L NO₂–N, which were far below the recommended MCL of 1 mg/L (= 1000 µg/L).



KEY WORDS: Shallow wells, Boreholes, Springs, Nitrate fertilizers, Microbial conversion of nitrate, Methemoglobinemia, Maximum contaminant level (MCL)


Bull. Chem. Soc. Ethiop. 2005, 19(1), 45-54.