Ecological and health risk assessment of heavy metal in dust from various medical centers

Indoor dust in healthcare facilities represents an important reservoir for toxic heavy metals and a potential exposure pathway for patients, healthcare workers, and visitors. This study investigated heavy metal concentrations , contamination sources , ecological and human health risks in indoor dust collected from 70 healthcare facilities in Yazd City, Iran. Contamination status was assessed using geochemical indices, while deterministic and probabilistic health risk assessments were performed following the USEPA framework. Potential metal sources were investigated using compositional data analysis (CoDA). CoDA distinguished lithogenic (Al, Cr, Fe, and Mn) from anthropogenic (Zn, Cu, Ni, Co, and Pb) metal assemblages, indicating distinct geochemical origins. Pollution Load Index (PLI) and Contamination Factor (CF) varied among healthcare facility types, suggesting differences in operational activities and waste management practices. Ecological risk assessment identified Pb, Cu, and Al as the principal contributors to ecological risk, with the highest values observed in maternal and child health units. Although the overall ecological risk was low, Cu and Pb exhibited comparatively elevated ecological risks, indicating potential input from medical waste, metal-containing pharmaceuticals, and discarded medical equipment. Health risk assessment identified ingestion as the dominant exposure pathway, followed by dermal contact and inhalation. Children exhibited higher non-carcinogenic and carcinogenic risks than adults owing to greater dust ingestion rates and lower body weight. In children, Ni and Cr were the predominant contributors to carcinogenic risk, with mean total cancer risks of 8.4 × 10⁻⁴ and 5.5 × 10⁻⁴, reperesting four to nine fold higher than adults. Monte Carlo simulation supported the deterministic risk estimates, while sensitivity analysis identified dust ingestion rate and metal concentrations as the primary sources of variability in risk estimate. These findings underscore the need for routine indoor dust monitoring, improved housekeeping, effective ventilation, and enhanced waste management to reduce heavy metal exposure in healthcare environments, particulary in maternal and child health units.