Grain Size Distribution and Health Risk Assessment of Metals in Outdoor Dust in Chengdu, Southwestern China

Abstract

A total of 27 outdoor dust samples from roads, parks, and high spots were collected and analyzed to investigate the contamination of 11 metals (Cr, Mn, Co, Ni, Cu, Zn, As, Sr, Cd, Sb, and Pb) in Chengdu, China. The results showed that the samples from the high spots exhibited the highest heavy metal level compared with those from the roads and the parks, except for Ni, Cu, and Pb. The dust was classified into five grain size fractions. The mean loads of each grain size fraction of 11 determined metals displayed similar distribution, and the contribution of median size (63-125, 125-250, 250-500 μm) fractions accounted for more than 70% of overall heavy metal loads. The health risk posed by the determined metals to human via dust ingestion, dermal contact, and inhalation was investigated. Oral and respiratory bioaccessible parts of the metals in dust were extracted using simulated stomach solution and composite lung serum. The mean bioaccessibilities of 11 investigated metals in the gastric solution were much higher than those in the composite lung serum, especially Zn, Cd, and Pb. Ingestion was the most important exposure pathway with percentage greater than 70% for both children and adults. Risk evaluation results illustrated that children in Chengdu might suffer noncarcinogenic risk when exposed to outdoor dust. Given that the cancer risk values of Pb and Cr larger than 1 × 10(-4), potential carcinogenic risk might occur for Chengdu residents through outdoor dust intake.

Heavy Metal Pollution in Settled Dust Associated with Different Urban Functional Areas in a Heavily Air-Polluted City in North China

“…Compared to dust from other representative cities in China (Table 1), the average concentrations of Mn, Co, Ni, Cd, and V in the settled dust from Shijiazhuang are close to that from the other cities; that of Cr is close to that from Xi’an [29], Wuhan [12], and Chengdu [30], but higher than that from Beijing [15] and Changchun [28]; that of Cu is close to that from Beijing [15] , Wuhan [12], and Chengdu [30], but higher than that from Changchun [28] and Xi’an [29]; that of Zn is close to that from Changchun [28] and Xi’an [29], but lower than that from Beijing [15], Wuhan [12], and Chengdu [30]; that of Pb is close to that from Beijing [15] and Xi’an [29], lower than that from Wuhan [12], but higher than that from Changchun [28] and Chengdu [30]. This comparison suggests a moderate pollution level of heavy metals in the urban dust from Shijiazhuang among representative cities in China, in agreement with the developing economic status of Shijiazhuang.…”

“…Additionally, concentrations of these metals in the local natural soil from Hebei Province [23], the Upper Continental Crust (UCC) [27], and dust from representative cities in China [12,15,28,29,30] are also given in the table. The average concentrations of Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb, and V in the settled dust are 141.4 ± 41.2, 562.3 ± 102.2, 43,348 ± 10,692, 14.9 ± 3.3, 42.1 ± 13.7, 107.3 ± 47.9, 514.5 ± 216.6, 2.84 ± 1.55, 177.0 ± 99.9, and 65.9 ± 14.9 mg·kg −1 , respectively.…”

Health risk of heavy metals in street dust

“…However, this is not consistent in the bibliography: depending on the heavy metals, the highest concentrations are identified in different particle sizes. For example, Chen et al (20) report that the highest concentrations for Co, Zn, As, Sr, Cd and Sb were effectively found in the less than 63 micrometers fraction, but for Ni and Cu the highest concentrations occurred in the median sizes (125-500 micrometers), and the mean Pb level is relatively higher in the coarsest fraction (500-1000 micrometers) (20). In addition to these different results, it is recommended that the smallest particle size is analyzed.…”

Characterization and preliminary risk assessment of road dust collected in Venice airport (Italy)

“…Several works utilized the more complex site specific modeling approach to evaluate the exposure pathways of RD matrix and the respective potential health risks (e.g. : Li et al, 2015;Chen et al, 2016;Wan et al, 2016;Yekeen et al, 2016). Instead, due to the different characteristics of RD and soil matrices, and the peculiarities of the monitored area, we preferred to apply the generic SSLs which are more stringent because they are calculated by EPA by using conservative assumptions about site conditions.…”

“…Indeed, most of the researches focused on this topic use the approaches provided by US Environmental Protection Agency which allow to estimate the soil contamination of superfund sites (USEPA, 1996(USEPA, , 2002, to evaluate the exposure pathways of RD matrix and the respective potential health risks (e.g. : Li et al, 2015;Chen et al, 2016;Wan et al, 2016;Yekeen et al, 2016).…”