BATTLING ARSENIC HAZARD THROUGH SUSTAINABLE TECHNOLOGIES FOR AQUATIC ECOSYSTEM RESTORATION

Geogenic arsenic (As) contamination of groundwater in South and Southeast Asian countries including Pakistan has become the environmental and public health issue due to its highly toxic effects. Several groundwater wells were tested to evaluate As contamination level, species and hydrogeochemical behaviour of As in aquifers along various flood plain of Pakistan. Results revealed that 68% of the wells contained As concentration above the World Health Organization safe limit for As in drinking water (WHO; 10 µg L⁻¹), and 38% wells exceeded the Pakistan EPA’s quality standard (50 µg L⁻¹). Arsenic content of wells at shallow depths (9–35 m) was below the WHO limit, indicating a safe zone for pumping of drinking water. Hydrogeochemistry of the aquifers was saline with dominance of Na-SO₄ and Na-Ca-HCO3 type water, low Fe content and alkaline pH. Various biochars and natural or modified biosorbents were evaluated for filtration of As from drinking water. We found that water melon rind-based filtration media, after mild modification, was the most potent product to remove As from drinking water of Punjab in Pakistan.