Assessment of flood-induced changes in soil heavy metal and nutrient status in Rajanpur, Pakistan

Flood events around the globe have severely impaired the soil functioning resulting in compromised food security in several parts of the world. The current study was aimed to explore the impacts of floods on soil heavy metals and nutrients status at three locations; Tibbi Solgi (TS), Vinri Khosa (VK), and Noshehra West (NW-control) in the district Rajanpur of Punjab, Pakistan. TS and VK sites were under regular influence of flooding over the last many years, but no flood event was reported on NW site during the same tenure; hence, it served as control. Sampling was carried out before and after flooding on the experimental sites. Vegetation cover was monitored through remote sensing techniques. Results revealed varying effects of floods on soil heavy metals; Cd, Cr, Pb, and soil phosphorous and nitrates. Flood events increased the Cd while lowered Pb concentration at VK site; however, flooding did not influence the status of Cr in soil. Similar to the trend observed in case of Cd, soil phosphorous and nitrates were reduced after flood events. Correlation analyses of soil physicochemical properties with soil heavy metals and nutrients indicated that after flood events, soil texture and organic carbon content seem to be the major factors driving the shift in soil heavy metals and nutrient concentrations. Although pollution indices indicated a marginally low contamination levels, but as projected in empirical studies, regular flood events in the studied sites may contaminate the whole ecosystem rendering it unfit for agricultural productivity.