Temporal pollution by nitrate (NO3), and ... - Academic Journals

Vol. 7(5), pp. 175-191, May 2013 DOI: 10.5897/AJEST2013.1421 ISSN 1996-0786 ©2013 Academic Journals http://www.academicjournals.org/AJEST

African Journal of Environmental Science and Technology

Full Length Research Paper

Temporal pollution by nitrate (NO3), and discharge of springs in shallow crystalline aquifers: Case of Akok Ndoue catchment, Yaounde (Cameroon) Wilson Y. Fantong1*, Alain T. Fouépé1, Issa1,2, Serges L. B. Djomou1, Hycinth S. Banseka3, Katsuro Anazawa4, Adelana SMA5, Jude W. Mendjo2, Festus T. Aka1, Takeshi Ohba2 , Joseph V. Hell1 and George E. Nkeng6 1

Institute of Geological and Mining Research (IRGM), Box 4110, Yaounde, Cameroon. 2 Department of Chemistry, Tokai University, Japan. 3 Global Water Partnership, Yaounde, Cameroon. 4 Department of Frontier Science, The University of Tokyo, Japan. 5 Department of Geology, University of Ilorin, Ilorin, Nigeria. 6 National Advanced School of Public Works, Yaounde, Cameroon. Accepted 11 May, 2013

Less than 30% of households in Yaounde have direct access to pipe-borne water. It is important to generate a time series on quality and quantity of spring water, which is an alternative source of water. Accordingly, temporal variation of NO3 and dissolved oxygen (DO), lag time of springs recharge by rainfall, discharge of springs and annual discharge of water from the Akok-Ndoue catchment was evaluated. Eleven springs, 3 wells and 1 rain gauge were investigated for 24 months. Flow rate, electrical conductivity, water temperature, DO, pH, water level in wells, rainfall amount and major ions were measured monthly. Temporally, the months of March, April, September and October are when the springs and shallow wells are polluted by NO3. Spatially, springs at lower altitudes are also susceptible to NO3 pollution. Rainfall depths from 125 to 275 and >275 mm/month recharge springs after 1 to 2 months, and less than 1 month, respectively. Moreover, when rainfall amount is