Concentrations, Source Characteristics, and Health Risk Assessment of Toxic Heavy Metals in PM2.5 in a Plateau City (Kunming) in Southwest China

Abstract

To explore the mass concentration levels and health risks of heavy metals in the air in dense traffic environments, PM2.5 samples were collected at three sites in the city of Kunming in April and October 2013, and January and May 2014. Ten heavy metals––V, Cr, Mn, Co, Ni, Cu, Zn, As, Cd and Pb––were analyzed by ICP–MS, and the results showed PM2.5 concentrations significantly higher in spring and winter than in summer and autumn, especially for Zn and Pb. The concentration of heavy metals on working days is significantly higher, indicating that vehicle emissions are significant contributors. An enrichment factor analysis showed that Cr, Mn, Ni, Cu, Zn, As, Cd and Pb come mainly from anthropogenic sources, while V and Co may be both anthropogenic and natural. The correlation and principal component analysis (PCA) showed that Ni, Cu, Zn, Cd and Pb mainly come from vehicles emissions and metallurgical industries; Cr and Mn, from vehicles emissions and road dust; and As, mainly from coal combustion. The health risk assessment shows that the non-carcinogenic risk thresholds of the heavy metals in PM2.5 to children and adult men and women are all less than 1. The carcinogenic risk of Cr for men and women in traffic-intensive areas exceeds 10−4, reaching 1.64 × 10−4 and 1.4 × 10−4, respectively.

Epidemiological Study on Health Risk Assessment of Exposure to PM2.5-Bound Toxic Metals in the Industrial Metropolitan of Rayong, Thailand

“…Aside from that, the daily PM2.5 concentrations (4.9-52.3 µg/m 3 ) found in this study were lower than those found in ambient air in the industrial zone in Khon Kaen province, Thailand (35.1-56.4 µg/m 3 ) [7]. Previous studies of ambient PM2.5 concentrations in urban industrial areas [5,15,32,33] revealed that the ambient PM2.5 concentrations of urban industrial areas in China were 2-7 times higher than the daily values in this study. These areas were Taiyuan (147 µg/m 3 ), Jiangjin (97.1 µg/m 3 ), Xi'an (50.6 µg/m 3 ), and near steel and glass industries at Kunming (130 µg/m 3 ).…”

“…According to the CR inh categories, an CR inh value <10 −6 is considered negligible, whereas a CR inh level >10 −4 is high risk. An acceptable or tolerable risk is represented by CR inh 10 −6 to 10 −4 [5,24].…”

“…CR age groups = CR inh × ADAFs × ED 70 years (5) The total lung cancer risk (TCR ic ) (for a population with an average life expectancy of 70 years) was combined across all the age groups (Equation ( 6)).…”

“…This finding is consistent with the findings of Hsu et al [13], who found high concentrations of K, Fe, Zn, and Pb in industrial estates in Taiwan that included steel making, oil refining, freight transport, and shipbuilding, the same types of industry found in Rayong. Zn, Cu, Ni, Mn, and Pb are the most common metals found in industrial zones [5,15,17,32,33]. To preserve the ambient air quality, the WHO has set limits on toxic metal concentrations (Table 1).…”

“…The International Agency for Research on Cancer (IRAC) has classified particulate matter in group 1 of human carcinogens [2]. PM2.5 is released during the combustion of fossil fuels and biomass, and their size is affected by their organic and inorganic composition, which then affects their potential for toxicity [3][4][5][6]. According to Sakunkoo et al [7], exposure to PM2.5-bound heavy metals in residential and industrial zones of Khon Kean, Thailand, has been linked to an increased risk of cancer in children.…”