Non-Lethal Assessment of Land Use Change Effects in Water and Soil of Algerian Riparian Areas along the Medjerda River through the Biosentinel Bufo spinosus Daudin

The land use change can negatively impact ecosystems, enriching water and soil with heavy metals (HMs). The fragile riparian areas along the Medjerda River of Northern Algeria are particularly affected by this phenomenon, and biological tools able to combine information about both matrices can be preferred in their monitoring. This research aimed to evaluate the suitability of the spiny toad (Bufo spinosus D.) as a biomonitor for assessing the impact of three different land uses (agricultural (AGR), urban (URB), and industrial (IND) managements) on soil and water for Cu, Fe, Pb, and Zn by using the non-lethal skin biopsy. The IND land use, followed by URB, mostly impacted soils for Cu and Pb, whereas management was not able to influence water differently despite worrying Pb levels. The cluster analysis allows to show that toad responds like soil in terms of land use and like water for HMs, as it is possibly related to the metal–chemical affinity. Although the single skin analyses do not display any difference among the managements, the bioaccumulation factor (BF > 1) shows that B. spinosus absorbs more HMs from water; skin accumulates Fe and Zn regardless of the land use, probably for both natural and anthropogenic assimilation and Pb and Cu for URB and IND, as it is related to their ionic forms and human impact.