In the past, the Mayo Kébbi served as the outlet of the
paleolake Mega-Chad.[3] The presence of
African manatees in the inflows of
Lake Chad is evidence of this, since the manatee is otherwise only in rivers connected to the
Atlantic Ocean (i.e. it is not possible that it evolved separately in an enclosed Chad Basin).[4] The grand scale of the Mayo Kébbi river course, is also evidence of earlier overflow from Mega-Chad; the upstream catchment of today is far too small to have dug such a large channel.[5]
Pollution
According to research carried out in 2017, the Mayo Kébbi river is being polluted by heavy metals such as: Cu, Cd, Pb, Fe, Mn, As, Zn, Ni and Cr and some sediments are being dropped in the river of which some are very toxic to the lives of the acquatic animals.[6]
^Leblanc et al. (2006). "Reconstruction of megalake Chad using shuttle radar topographic mission data". Palaeogeography, palaeoclimatology, palaeoecology 239, pp. 16–27
ISSN0031-0182 1872-616X