Health risk assessment of source-specific elemental carbon (using dual carbon isotopes) and heavy metals in the Tibetan Plateau

Abstract

We assessed the health risks associated with atmospheric heavy metals (HMs: Mn, Zn, Co, Cu, V, Ni, and metalloid As) and elemental carbon (EC) at three sampling sites across the Tibetan Plateau (TP). The highest annual concentrations of HMs (80.7 ng m-3) were observed in the northeastern TP (Qinghai Lake), while the highest annual concentration of EC (1.9 mu g m-3) was found in the southwestern TP (Ngari). Mn and As were major contributors to the Hazard Quotient (HQ) and the incremental lifetime cancer risk (ILCR). Peak HQ and ILCR values were observed during the winter seasons. The HI (Hazard Index) of HMs for children exceeded safety thresholds. Health risk assessments for EC indicated no significant non-carcinogenic risk (non-CR) but significant carcinogenic risk (CR) effects in the TP. Higher risks of HMs were found during the dust-rich period (DRP) compared to the normal period (NOP), while EC posed lower health risks during the DRP. Based on dual carbon isotope analyses, the source-specific contributions of EC to health risks were attributed to biomass burning (30.4 %), coal combustion (28.7 %), and liquid fossil fuel combustion (41.0 %), respectively. These findings improved our understanding of the health effects associated with dust exposure and the source-specific health risks of EC in the remote areas