Global and local ecological impacts of chloride-based road deicing salts

Abstract

Chloride-based road deicers are commonly used for winter road maintenance but can be detrimental in both terrestrial and aquatic environments. The objective of this thesis was to investigate the impacts of road salting both globally and locally in Halifax, Nova Scotia. A metaanalysis of the impacts of road salting across individual, community, and ecosystem levels found that road salt can have significant negative effects across ecological scales. Locally, fifteen wetlands across Halifax were tested to determine whether direct stormwater outflows impacted salinity and soil mineral concentrations more than runoff and identify whether these sites were salinized above recommended thresholds. Although all fifteen wetlands were above the threshold, direct stormwater outflows were not found to significantly impact wetland soil salinity, suggesting that other factors (such as urbanization) may be affecting the salinization of these wetlands. This thesis highlights the need for further research on road salting impacts in understudied ecosystems.