Ecological Risk Assessment of Some Heavy Metals in the Dust Emitted from Non-Metallic Industries of Ardakan County of Yazd in Summer 2018: A Descriptive Study

Implementation of industrial development programs, without considering environmental considerations has caused continuous entrance of pollutants to air. Therefore, the purpose of this study was assessing the ecological risk of some heavy metals in the dust of a number of non-metallic industries and determining the best indices in pollution assessment of Ardakan area.

This descriptive study was conducted in the summer season of 2018 by installing dust traps around a number of non-metallic industries. After collecting dust, concentrations of zinc, lead, arsenic, aluminum, cobalt, iron, beryllium and molybdenum were measured by inductively coupled plasma mass spectrometry apparatus. Then, heavy metals pollution level was evaluated based on the number of single and integrated ecological indices. Data were analyzed using descriptive tests.

The mean concentrations of zinc, lead, arsenic, aluminum, cobalt, iron, beryllium and molybdenum in all samples were measured 961, 62.08, 19.19, 13.32, 36527.91, 1.42 and 2.22 mg/kg, respectively. Based on the single pollution index,  lead, zinc and arsenic elements in the class of severe pollution and based on the single index of contamination factor, two zinc and aluminum elements were in the very high pollution class. The pollution class of the integrated indices of contamination degree and modified degree of contamination varied from significant to very high and medium to high, respectively. Based on the integrated index of pollution load, all samples were in the contaminated class.

The single ecological indices are the best indices in assessing the severity of dust pollution of the area and among the studied elements, zinc metal was introduced as a critical metal.