Mercury levels in road dust and household TSP/PM2.5 related to concentrations in hair in Guangzhou, China

Road dust, household total suspended particulate matters (TSP) and PM2.5 were collected in urban area of Guangzhou, south of China, to investigate the concentrations of total mercury (THg) and methyl mercury (MeHg). The household PM2.5 concentrations varied between 16.2 and 623 μg/m3. The average PM2.5 level (174 μg/m3) from all of the locations exceeded 24-h concentration from WHO air quality guideline The average concentrations of THg and MeHg were: 235 μg/kg and 0.392 μg/kg in road dust, 600 μg/kg and 1.49 μg/kg in TSP; 1006 μg/kg (104 pg/m3) and 1.40 μg/kg (0.134 pg/m3) in PM2.5. Risk assessment showed that the Hazardous quotients (HQs) of exposure to Hg and MeHg via road dust and TSP were less than 1, indicating that no adverse risk was manifested. Ingestion of dust was found to constitute a relatively minor pathway of Guangzhou residents′ exposure to Hg. Furthermore, human hair samples from 88 Guangzhou citizens were also analyzed to investigate the mercury accumulation in human body in Guangzhou. The average concentrations of THg and MeHg in human hair samples were 869±831 μg/kg and 104±108 μg/kg respectively. However, no significant correlations of the mercury species were noted between human hair and road dust, TSP and PM2.5.

► The indoor PM2.5 levels were much higher than international air quality guidelines.
► Hg level of road dust was distinctly higher than other countries.
► THg and MeHg tend to be enriched in household particles other than road dust.
► Hg loadings in human hair were correlated to age and duration in Guangzhou.
► No significant correlations of Hg and MeHg between hair and particles were noted.