Assessing the Environmental Risks of De-icing Materials Used in Winter Operations (A case of Study of the Hydrochemical Quality of Hamedan-Bahar Basin)

Despite the wide application of de-icing substances to the roadways, the sewage produced can have negative impacts on local ecosystems. Hence, the present study was conducted for assessing the effects of road salt use throughout the winter in Hamedan on the hydro-chemical quality of Hamedan-Bahar basin. Hamedan is one of the major tourist destinations and one of the main agricultural poles in Iran, and thus, its water resources contamination may pose serious risk to the health of the whole country.

The modeling of under-ground water flow paths in the study area revealed that the flow of rain and snow water in the city is mainly towards Hamedan-Bahar basin (as one of the main drinking water and agricultural water supplies in the region). Therefore, the 24 wells in the study area were sampled and the hydro-chemical characteristics of the obtained water samples as well as their changing trends over the past 10 years were determined and analyzed.   

The results indicated a gradual increase in the minerals and solid materials in the water of the basin. This, considering the meaningful correlation values obtained (R2≥0.89) between the salt contents and Cl- and Na+ concentrations, could be attributed to the use of de-icing materials. The rate of pollutants in some of the samples was found to be 10 times as much as the permissible national standard and international values. Moreover, based on the Wilcox diagram, the water in most stations could be classified as C3S1 (decreasing the soil fertility and resulting in ecophysiological abnormalities in crops) and even as C4S1 (completely harmful for irrigation). A similar distribution of de-icing compounds and arsenic were observed in the under-ground water of the basin. 

The increase in the pollution and the decline in hydro-chemical properties of the basin due to the accumulation of de-icing materials, not only pose direct hazardous effects to human health and agricultural lands but can also intensify the mobility of the heavy metals in soil-water profiles of the region. Therefore, it is suggested that winter operations in the city be planned and carried out using modern methods and facilities (such as anti-icing program, eco-friendly deicers, asphalt mixture with anti-icing additives, hydronic heating pavement), so that the negative environmental impacts can be controlled as much as possible.