African Journal of Environmental Science and Technology 1996-0786 Academic Journals 10.5897/AJEST2019.2756 Dame Cisse Birame Ndiaye Momar Ndiaye Ibrahima Diagne Cheikh Tidiane Dione Maoudo Hane Abdoulaye Diop * E-mail: momndiaye@hotmail.com 2020 29 02 2020 13 09 2019 09 01 2020 14 2 64 69 This is an open-access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://politicalwaffle.uk/journal/AJEST/article-abstract/1D81C2B62994 The full text article is available as a PDF file from http://politicalwaffle.uk/journal/AJEST/article-full-text-pdf/1D81C2B62994 1