Health risk assessment of lead-zinc mine tailing in Angoran, Zanjan, Iran

Comprehending the characteristics of heavy metal contamination within mine tailings and its ramifications on ecological and human well-being holds paramount importance in formulating effective preventive and ameliorative strategies. This investigation evaluates the health hazards posed by the tailings originating from the Angoran lead-zinc mine situated in Zanjan province, Iran. The mine generates two distinct types of tailings: hot filter cake (referred to as cobalt cake or S2) and cold filter cake (nickel cake or S1). Twenty subsamples were procured from each type of tailing and subjected to analysis at the pollution research laboratory of University of Zanjan. The quantification of lead (Pb), zinc (Zn), arsenic (As), cadmium (Cd), nickel (Ni), copper (Cu), chromium (Cr), mercury (Hg), manganese (Mn), and antimony (Sb) concentrations was accomplished through the utilization of inductively coupled plasma mass spectrometry (ICP-MS). Carcinogenic and non-carcinogenic risk assessment indices were computed. Moreover, the limits of detection (LOD) and quantification (LOQ) for the measurements were established using blank solutions prepared as samples for assessment. The Hazard Index (HI) surpassed unity for Pb, Zn, Cd, As, Hg, and Mn in both types of tailings, signifying non-carcinogenic risk exposure for both children and adults. Furthermore, the HI for Pb and As also exceeded unity for adults. Consequently, both age groups were subject to non-carcinogenic hazards, with children encountering notably elevated risks. The chief pathways for exposure to heavy metals and the ensuing non-carcinogenic risks encompassed ingestion, inhalation, and dermal contact. The cumulative risk threshold for carcinogenic outcomes, in accordance with USEPA standards, ranged between 1.00E-04 and 1.00E-06. In this inquiry, the overall risk for children associated with tailing S1 and S2 amounted to 2.39E-03 and 5.00E-03, respectively, markedly surpassing the acceptable threshold. Furthermore, the cumulative risk for adults pertaining to tailing S1 and S2 stood at 1.27E-03 and 4.68E-03, respectively, indicating the presence of carcinogenic perils in the adult demographic. image