ColFeroX offers a solution to mitigate spreading of contaminations (especially toxic heavy metals such as Zn, Pb, Cu, As) in groundwater. An adsorptive in-situ barrier is created underground using Iron-oxide particles, which filters out the contaminations while allowing groundwater to flow through the barrier. ColFeroX offers a safe, fast, cost-effective, one-time application to remove contaminations from groundwater instead of current pump&treat method, which requires infrastructure, high costs, and continuous maintenance.