Comparative Health Risk Assessment of Heavy Metal Contamination in Indoor Dust From University Dormitories in Erbil, Iraq.

Abstract

This investigation aimed to evaluate the possible health hazards linked to heavy metal exposure in indoor dust samples gathered from two university dormitories at Salahaddin University: the 18 Shobat dormitory for females and the Shahid Shawkat dormitory for males. A total of 100 dust samples (50 per dormitory) were collected in May 2025 and analyzed for iron (Fe), manganese (Mn), copper (Cu), arsenic (As), lead (Pb), and cadmium (Cd) using energy-dispersive X-ray fluorescence. Results revealed substantially higher mean concentrations of most metals in Shahid Shawkat, located near a high-traffic road, compared to 18 Shubat. The average concentration of As at Shahid Shawkat dormitory was 9.53 ppm, more than double the 3.70 ppm recorded at 18 Shubat (p = 2.9 × 10^-15). Pb levels exhibited a similar trend, with mean values of 85.1 ppm and 49.0 ppm, respectively (p = 2.5 × 10^-13). Mn concentrations were likewise markedly elevated in Shahid Shawkat, reaching 187 ppm versus 72.9 ppm at 18 Shubat (p = 2 × 10^-16). This suggests that proximity to major traffic routes substantially influences indoor dust compared to the 18 Shubat dormitory. Principal component analysis demonstrates that heavy metal accumulation in the dormitories is affected by external environmental pollution, particularly for Fe, Mn, As, Pb, and Zn, as well as internal sources, especially for Cd and Cu. Non-carcinogenic risk assessment showed all hazard index (HI) values below 1, with As posing the highest risk in Shahid Shawkat (HI = 1.18 × 10^-1) and Mn in 18 Shubat (HI = 3 × 10^-2). The findings indicate that proximity to major roads contributes to indoor dust contamination, emphasizing the importance of targeted measures to reduce chronic exposure among students.