Fig. 3: Comparison of high 3H in groundwater versus various parameters.
From: Groundwater vulnerability to pollution in Africa’s Sahel region
a–d, Selected PDPs from among the (spatially continuous) predictor variables used in the RF model (Fig. 2): aridity (a), elevation (b), lithology (c) and aquifer porosity (d). The full set of PDPs is displayed in Supplementary Fig. 3. e–f, Two-sided Kendall rank correlations between the proportion of high 3H measurements in bins of the in situ parameters of depth (e) and nitrate (f). The full set of correlation plots is shown in Supplementary Figs. 1 and 2.
