AUTHORS’ CONTRIBUTION
S.F. is the project leader. S.F., D.S., A.B., G.L. and S.M. were responsible for experimental and project design. S.M. was responsible for samples collection. A.S. performed some of the experiments. A.B. and S.M. performed most of the experiments and calculations. S.M. prepared, sorted and packaged the samples for shipment from Nigeria to France. S.F., D.S., G.L., A.B. and S.M. made conceptual contributions.