ABSTRACT
Objective To analyze characteristics of heavy metals in metro station’s airborne PM2.5 and to evaluate its health risk in a South China city. Methods A metro stations were selected for the study. Sampling sites of metro station included ground control, station hall and platform. The PM2.5 sampling was conducted one time per day for three consecutive days. The concentrations of ten heavy metals (As、Cr、Cd、Ni、Hg、Pb、Mn、Sb、Se、Cu) were determined. Inhalation exposure to these heavy metals2.52.5 range from 0.06 ng/m3 to 49.22 ng/m3. The concentrations of Mn、Cr and Ni in metro station’s airborne PM2.5 were respectively 3.75 times, 2.23times and 2.12 times higher than those in ground control. Increased lifetime cancer risk of carcinogenic heavy metal Cr exposure outrange the acceptable level (10-6) when its exposure time exceed 5 hours per day for lifetime. Cancer risk of carcinogenic heavy metal As exposure outrange the acceptable level (10-6) when its exposure time for adult male population exceed 8 hours per day for lifetime. Non-carcinogenic hazards risks of heavy metal Mn、Cu、Pb、Se、Hg and Sb in metro station’s airborne PMPM2.5 were little. Conclusions Airborne particulate matter in metro station has become one of the important sources of heavy metal exposure. Further attention should be paid to the possible carcinogenic risk of heavy metals in metro station’s airborne PM2.5 for long-term exposure.
ABSTRACT
Objective @#To investigate the pollution of metal elements in PM2.5 at the metro station by monitoring, so as to provide evidence for health protection strategies.@*Methods@#The PM2.5 concentrations on the platforms, in the tunnels, and above the ground of two selected metro stations in some city were collected and measured by electronic balance. The concentrations of Fe, Al, Cu, Mn, Ni, Pb, Zn, Cr, Ba and Cd in PM2.5 were determined by inductively coupled plasma mass spectrometry (ICP-MS). The pollution index (PI) and enrichment factor (EF) of these elements were analyzed.@*Results@#The concentration of PM2.5 was (101.46±32.88) μg/m3 on the platforms, (104.42±32.95) μg/m3 in the tunnels and (74.25±13.29) μg/m3 above the ground. The highest Fe concentrations were (33.19±5.93) μg/m3 on the platforms and (39.95±11.56) μg/m3 in the tunnels, accounting for (33.73±9.40)% and (42.72±17.17)% of PM2.5. The average PI values of Fe, Mn and Ba in PM2.5 on the platforms were 29.67, 9.24 and 7.13, in the tunnels were 36.30, 11.23 and 8.30, respectively, with very high level of pollution; the average EF values of Fe, Mn and Ba in PM2.5 on the platforms were 20.15, 4.55 and 4.33, in the tunnels were 19.44, 4.16 and 4.07, with serious, medium and medium level of enrichment, respectively.@*Conclusion@#The main metal pollutants in PM2.5 at the metro station are Fe, Mn and Ba, which are enriched in the metro environment.