Potential ecological risk assessment of heavy metals (Cr, Ni, and Co) in serpentine soil at Ginigalpelessa in Sri Lanka

Soil contamination by heavy metals creates adverse impacts on human health, agricultural production, and ecological functions in the local ecosystem. In this context, serpentinite weathering is an event that can produce heavy metal (Cr, Ni, and Co) anomalies in the local soil profiles. Therefore, weathered rock (WR), soil, and plant samples were analyzed to evaluate the soil contamination and its probable risk to the plants and human health in Ginigalpelessa serpentinite outcrop in Sri Lanka. The results revealed that soil is severely contaminated with Cr, Ni, and Co, which was confirmed by corresponding high index of geoaccumulation (Igeo), enrichment factor (EF), contamination factor (CF), and degree of contamination (Cdeg) values. According to the individual potential ecological risk factor (Er) values and calculated potential ecological risk index (PERI) value, Cr, Ni, and Co showed a very high degree of ecological risk to biological communities in the area. According to the human health assessment on non-carcinogenic scenarios, total exposure hazard index (HIt) values for adults implied that both residential and agricultural scenarios (2>HIt>1) possess obvious non-carcinogenic effects for adults. Similarly, HIt values for children were calculated as 7.36 and 7.08 for residential and recreational scenarios, respectively. These values suggested that children were highly vulnerable to possess obvious non-carcinogenic effects than adults. Moreover, a questionnaire survey was carried out to evaluate the health problems in the area. The results showed that skin rashes and kidney disease contribute to 82% and 12% of the total health issues, respectively. In this regard, children were identified as the main victims (contribute for 54% of patients), and people above the age of 45 were the second victimized age category (contribute for 38% of patients). Based on the above results, present study also provided useful insights to execute a phytoremediation approach via colonization of heavy metal hyperaccumulators in identified risk-prone critical areas as a solution to the people in this area who have suffered through no fault of their own.