The use of permeable reactive barriers to control contaminant dispersal during site remediation in Antarctica

When used as part of an integrated contaminated sites remediation program, permeable reactive barriers are a valuable technological application that c an remove, retain or treat contaminated waters in seasonally frozen ground in remote areas. The main advantages of permeable reactive barriers for app lication in remote cold regions are that they are passive low-technology sy stems that do not require power to operate; they can be left at short notic e during extreme weather events; and most importantly, they have a minimal impact on the environment as they can be completely removed at the end of s ite operations. However, barrier technology was originally developed for us e in temperate regions and site-specific adaptations are required to ensure effective deployment and recovery from seasonally frozen around. Experienc e gained from testing a variety of fill materials on site at Casey Station, Antarctica, indicates that fine-grained reactive materials are less suitab le than coarse-grained (free-draining) materials. Preliminary results from simple field trials using granular activated carbon indicate that a signifi cant improvement in water quality is possible for waters that contain high concentrations of petroleum hydrocarbons and heavy metals. For remote area deployments barriers are best pre-assembled in modular form to allow rapid emplacement in frozen ground before seasonal melting begins. Future develop ments that are needed for efficient application in cold regions include the need to quantify reaction/adsorption rates at low temperatures for fill me dia and to establish breakthrough curves for promising materials. (C) 2001 Elsevier Science B.V. All rights reserved.