Establishment of Location-Specific Application Rate Guidelines for Anti-icing and De-icing Chemicals through an Ambient Monitoring System
Construction and Maintenance Practices
Environmental Process, Natural Resources
Research Idea Scope
Departments of Transportation (DOTs) throughout the United States are responsible for keeping state and federally owned/operated transportation corridors safe and operational during winter months when snow and ice can accumulate on highways. The application of anti-icing and de-icing chemicals by DOTs has become one of their most effective practices in their winter storm management efforts. It is widely known that chemical additives related to winter storm management activities can impact water quality and soil salinity. Chemical additives have the potential to migrate through the soil into groundwater or by runoff and drainage directly into surface water; as well as accumulate in the soil profile and impact the survivability of vegetation along the corridor. The primary factors in determining environmental impacts resulting from the use of chemical additives are the type and amount of chemicals used. An increase in the amount of chemical additive applied to a transportation corridor equates to an increased potential for additives in pavement runoff and snowmelt. Yet, the total amount of chemicals used will depend largely on the number and severity of winter storms being managed. Unfortunately, the over-application of the chemical additives can often result in environmental impacts. In order to evaluate winter storm management operations to mitigate potential environmental impacts, it is necessary to create a mechanism for reviewing the effectiveness and effects of chemical additive application rates. It is herein being proposed that this be accomplished by correlating the type and quantity of chemicals applied, the winter storm events and roadway conditions, and soil samples (and plant tissue samples where applicable) from monitoring sites adjacent to the target roadway both before and after the winter season. For the research project, each DOT operator performing anti-icing and de-icing activities will be required to accurately record their chemical usage through the use of manual or automated logging methods. These logs will be used to record the types of and application rates of additives, the locations where these are applied, and the general effectiveness of the applications. By measuring and recording the quantity of chemicals applied and observing the effectiveness of the application, it should be possible to optimize the amount of chemical applied to the road (i.e., apply the least amount of chemical to achieve the desired effect). The effects of the type and amounts of chemical additives applied are then evaluated by correlating changes in soil chemical and plant tissue concentrations (i.e., calcium, magnesium, etc.) alongside the road.
Urgency and Payoff
One of the key approaches to minimizing environmental impacts is the consistent use of best management practices (BMPs) such as the use of application rate guidelines, recordkeeping of chemical usage, and subsequent evaluation of those application rates. The desired outcome of this research is to recommend initial application rate guidelines, implement a winter storm management recordkeeping system of chemical usage along transportation corridors, and define how best to evaluate that information to minimize potential environmental impacts. The focus of the research will be to identify trends indicating the accumulation of chemicals along transportation corridors and observed or potential impacts to natural resources associated with these accumulations.
Emily L. Christ, MEP, JD, Arizona Department of Transportation