Seasonal profile of nitrate and nitrite in potable water sources in Onitsha, Nigeria

✍ Scribed by Ezeonu, F. C. ;Okaka, A. N. C.

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 388 KB
• Volume: 11
• Category: Article
• ISSN: 1053-4725
• DOI: 10.1002/(sici)1098-2256(1996)11:2<99::aid-tox4>3.0.co;2-3

✦ Synopsis

A general steadiness in the seasonal changes of nitrate and nitrite concentrations in potable surface and ground waters in the Onitsha metropolis was observed. Spectrophotometric analysis revealed that nitrate concentration values for the months of May 1990, August 1990, November 1990 and February 1991 showed a consistent decrease of the magnitude 26.50 k 0.71, 14.20 ? 1.33, 3.80 k 0.40, and 3.40 k 0.7 ppm correspondingly for well water; 7.02 ? 1.2, 2.17 k 0.61, 1.29 k 0.50, and 1.56 ? 0.91 ppm for borehole water: and 2.28 k 0.60, 1.22 k 1.30,0.62 ? 0.20, and 0 ppm for surface streams. The nitrate concentration in all cases attained a slight equilibrium between November and February, the peak periods of the dry season.

Nitrite concentrations of these water samples showed an inverse relationship to nitrate concentrations. Nitrite concentration values of 5.40 ? 0.70, 5.03 k 0.90, 7.50 k 0.30, and 10.60 r 0.80 ppm were observed in the well water; and 0.76 k 0.70, 1.20 t-0.90, 2.00 ? 0.33, and 3.50 k 1.00 ppm for borehole water for the corresponding months. Nitrite was at no time detected in the surface streams.