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Journal of Chemistry
Volume 2013, Article ID 196516, 4 pages
Research Article

Impact of Nitrogen Fertilizer Applications on Surface Water Nitrate Levels within a Kenyan Tea Plantation

1Department of Chemistry and Biochemistry, Pwani University College, P.O. Box 195, Kilifi 80108, Kenya
2Department of Chemistry and Biochemistry, Chepkoilel University College, P.O. Box 1125, Eldoret 30100, Kenya
3Department of Soil Science, Chepkoilel University College, P.O. Box 1125, Eldoret 30100, Kenya

Received 22 June 2012; Revised 13 November 2012; Accepted 20 November 2012

Academic Editor: Isabel Seiquer

Copyright © 2013 J. K. Maghanga et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Tea production in the Kenyan Rift Valley uses high rates of nitrogenous fertilizer. Nitrates can be discharged to water bodies through leaching and surface run-off. Nitrate levels above 10 mg/L –N cause methemoglobinemia which is fatal. A study to monitor changes in surface water nitrate levels was carried out in ten rivers within a Kenyan tea plantation for three years. Water samples were obtained before and after fertilizer application in 2004, 2005, and 2006. Nitrate-nitrogen ( –N) was determined colorimetrically by the cadmium reduction method using HACH-DR 2400 dataloging spectrophotometer. For the three years, the highest nitrate-nitrogen levels were in river Temochewa in 2005 during the first fertilizer applications (4.9 mg/L to 8.2 mg/L). There was no established trend between surface water nitrate levels and the time of fertilizer applications; however, fertilizer application contributed to an increase in nitrate levels. The initial nitrate-nitrogen levels in most of the rivers were high, indicating that contamination could have been upstream; hence, further research is required to establish this. Nitrogen-nitrogen levels in the three years were below the maximum contaminant level of 10 mg/L –N; however, the rivers should be monitored frequently.