Trace Element Contamination in Water and Associated Health Risks: Rara and Ghodaghodi Ramsar Lakes, Nepal

This study investigates the concentrations of trace elements and assesses associated health risks in two Ramsar sites of western Nepal: Lakes Rara and Ghodaghodi. Water samples were collected during the 2019 pre-monsoon and post-monsoon seasons from sites selected according to land use patterns, potential stressors, and accessibility. The concentrations of 12 trace elements (Al, V, Cr, Mn, Fe Co, Ni, Cu, Zn, Cd, Pb, and As) were determined using Inductively Coupled Plasma-Mass Spectrometry. The enrichment factor (EF) was computed to evaluate anthropogenic influences. Additionally, we calculated the metal index (MI), potential ecological risk index (RI), and health risks, encompassing both non-carcinogenic and carcinogenic effects. Iron was the most prevalent trace element across both lakes, followed by aluminium. Water from Ghodaghodi exhibited significant enrichment of Cr, Ni, Zn, As, and Cd, while only As and Cd were highly enriched in Rara. The metal index (MI) values of all the trace elements except Fe and Mn are less than unity in both the lakes. This study further indicates that there are no ecological and non-carcinogenic health risks from both lake waters. However, the carcinogenic risk for As, Cd, Pb, and Cr was "very low" via dermal contact, whereas the risk from ingestion ranged from "very low" to "medium" in both lakes.