Canadian Soil Quality Guidelines for the Protection of Environmental and Human Health - Propylene Glycol

his fact sheet provides a summary of a review by the CCME Soil Quality Guidelines Task Group (SQGTG) of the implications of propylene glycol (PG) releases to Canadian soil environments. Following a review of the releases, fate and effects of PG in soils, the SQGTG opted not to develop Canadian soil quality guidelines at this time. Nonetheless, releases of PG to the environment can pose serious risks for groundwater supplies and aquatic life in surface water bodies, due to the high biochemical oxygen demand (BOD) associated with rapid microbial breakdown of PG. This high BOD in turn may result in depressed oxygen concentrations and low redox conditions in surface and groundwater, with a large number of secondary effects on geochemistry, microbial productivity, and the viability of aquatic life. PG releases may be managed in part through the use of propylene glycol Canadian Water Quality Guidelines for the protection of aquatic life (CCME 1999). Use of aircraft de-icing fluid represents one of the largest sources of PG release to the environment. In addition to issues associated with PG release, managers of de-icing activities should be aware of the environmental risks associated with other possible additives in commercial deicing solutions; in particular triazoles added as corrosion inhibitors, and alkylphenol ethoxylates (including nonylphenol ethoxylates) that may be added as surfactants.