Nitrate and nitrite contamination of water sources and fruit juices marketed in South-Eastern Nigeria

The nitrate and nitrite contents of eight brands of fruit juices, 12 brands of sachet water (pure water) purchased at retail outlets from some parts of South-Eastern Nigeria, and water samples collected from 15 wells, 12 bore-holes, 10 streams/rivers, six taps (municipal water supply) and two samples from central sewage effluents between the months of August-November (4 months) from Umuahia, Abia State, Nigeria were estimated. Nitrite was estimated spectrophotometrically and nitrate after reduction to nitrite with cadmium column. All the samples analysed contained detectable levels of nitrate and nitrite. For nitrate, the mean values in mg/L ranged from 0.46+/-0.10-7.64+/-2.20, 9.74+/-2.02-20.06+/-1.32, 3.12+/-1.17, 1.07+/-0.5, 11.18+/-10.48, 3.05+/-1.22 and 120.12+/-15.48, for sachet water, fruit juices, bore-holes, streams/rivers, wells, taps and central sewage effluents, respectively. The mean concentration of nitrite in mg/L in those samples ranged from 0.19+/-0.01-4.78+/-1.30, 3.10+/-0.23-9.65+/-2.21, 0.68+/-0.47, 0.32+/-0.18, 0.73+/-0.44, 0.63+/-0.42 and 18.88+/-1.20 following the order above. The levels of nitrite detected in all the brands of fruit juices and three brands of sachet water (Brands B, E and J) exceeded the acceptable daily intake (ADI) recommended by WHO's for children less than 10 kg body weight, while the levels of nitrate in all the samples fall below WHO's, ADI for nitrate. The results are discussed from toxicological, industrial and agricultural points of view. (C) 2003 Elsevier Science Ltd. All rights reserved.