Pollution characteristics and related health risk of heavy metals in PM_2.5 in Shenyang city of Liaoning province

  Objective  To investigate the concentration of particulate matter less than 2.5 μm in aerodynamic diameter (PM_2.5) and the pollution characteristic of heavy metals in the PM_2.5 in Shenyang city of Liaoning province.

  Methods  PM_2.5 samples were collected in Shenyang city from February 2014 through October 2017．Chromium (Cr), manganese (Mn), nickel (Ni), arsenic (As), selenium (Se), cadmium (Cd), antimony (Sb), lead (Pb), and mercury (Hg) were extracted from the samples with 10% nitric acid (HNO₃) solution at 60℃ with ultrasound bath, then determined with inductively coupled plasma mass spectrometry (ICP-MS). The pollution characteristics and health risk of heavy metals in PM2.5 were analyzed.

  Results  The average daily mass concentration of PM_2.5 was 68.4 μg/m³ during the period, which was under the national secondary standard for ambient air quality (75 μg/m³). The descending order for average concentrations of metal elements detected in the PM_2.5 samples was Pb, Mn, As, Cr, Sb, Ni, Se, Hg, and Cd. The concentration of As was above the reference limit concentration of the national ambient air quality standard. The non-carcinogenic hazard quotient (HQ) for the 9 non-carcinogenic heavy metals were all less than 1. For the 4 carcinogenic heavy metals, the carcinogenic risk of Ni was lower than the acceptable risk level (10^–6), but that of Cr, As, and Cd were higher than 10^–6.

  Conclusion  The non-carcinogenic risk associated with the heavy metals in PM_2.5 is not significant but carcinogenic risk related to the heavy metals in PM_2.5 exists in some content in Shenyang city.