Development of ADOT Application Rate Guidelines for Winter Storm Management of Chemical Additives through anAmbient Monitoring System.

摘要

The Arizona Department of Transportation (ADOT) is responsible for keeping state and federallyowned/operated transportation corridors safe and operational during winter months when snow and iceaccumulate on these roads. A common practice is the application of anti?icing and deicing chemicals, primarilysodium chloride (salt). ADOT’s Winter Storm Management Operations Manual (WSMOM) presents guidelinesfor the application of anti?icing and deicing chemical based on specific storm events and roadway conditions.Sodium and chloride can be dispersed to areas adjacent to roadways though melting snow and ice and byvehicle splash and spray. Upon reaching vegetation and soil, these compounds can negatively impact theenvironment. To evaluate the relationship between salt applications and potential impacts to soil andvegetation, data from winter storm management activities (frequency of application, quantity of salt applied,and adherence to ADOT WSMOM guidelines) were compared to sodium and chloride concentrations in soil andvegetation samples collected at varying distances from the roadway. Data collection and review included 16sites along State Route 260 and U.S. Routes 180 and 191, all in ADOT’s Globe District. Analyses of soil andvegetation samples show that sodium concentrations are greatest nearest the roadway and decrease withincreasing distance from the roadway. There is no evidence that sodium concentrations in the soil exceed levelsconsidered tolerable for vegetation, nor is there a significant seasonal difference between fall readings andspring readings of sodium and chloride concentrations in soil and vegetation. Additionally, sodiumconcentrations in soil samples did not appear to have a statistically significant impact on the level of sodium invegetation samples. Therefore, it cannot be concluded that sodium concentrations in soil are directly impactingsodium concentration in vegetation near the roadway. There is no evidence to support that ADOT shoulddeviate from its current chemical application rate guidelines.