THE EFFECTS OF SNOW AND ICE ON THE ENVIRONMENTAL BEHAVIOR OF HYDROPHOBIC ORGANIC-CHEMICALS

A review is presented of the roles of snow and ice as they influence t he environmental fate of hydrophobic organic chemicals (HOCs). Measure ments of HOC concentrations in snow are reviewed and present informati on on the partitioning and depositional and post-depositional behaviou r of HOCs in snow is described and implications for environmental moni toring and assessment of fate are discussed. It is concluded that snow is an efficient scavenger of HOCs from the atmosphere both by adsorpt ion of gaseous HOCs to the ice interface, and by particle scavenging. The post-depositional fate of HOCs in ageing snow packs is poorly unde rstood. Suggested structures of quantitative models describing HOC int eractions with ice and snow are presented. Key parameters in these mod els include the interfacial area of snow and the extent of HOC sorptio n to the ice surface. Recent laboratory determinations of these parame ters are reviewed. Finally, research needs and gaps are identified wit h a view to compiling more accurate estimates of net atmospheric wet d eposition of HOCs, establishing their fate in snow packs, developing r eliable sampling protocols and assessing the usefulness of the glacial record as an indicator of past atmospheric compositions. (C) 1998 Els evier Science Ltd. All rights reserved.