College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Tianjin, 300350, China.
College of Environmental Science and Engineering, State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, Nankai University, Tianjin, 300350, China.
Environ Pollut. 2019 Nov;254(Pt B):113113. doi: 10.1016/j.envpol.2019.113113. Epub 2019 Aug 26.
Rapid industrialization and urbanization have resulted in widespread pollution of airborne particulate matter (PM) containing various heavy metals with adverse human-health effects. Health risk assessment of PM calls for accurate evaluation of the bioaccessibility, instead of the total content, of heavy metals in PM. Here, we demonstrated that the leachable fraction of particle-bound As, Pb, Cr, Mn, Cd, Cu, Ni and Zn in lung fluid within the typical retention duration of particles in human lungs varied drastically among particles originated from different air pollution sources, including coal combustion, biomass combustion, fugitive dust, road dust, construction dust, cement and soil. Moreover, bioaccessibility of heavy metals, particularly in biomass combustion, cement and soil particles, was strongly dependent on pollution sources, and the particulate Cu, Ni, Pb and Cd appeared to be the primary indicators of the source dependence of heavy metal bioaccessibility. Using total rather than bioaccessible concentrations of particle-bound heavy metals not only led to overestimation of the health risk of source particles, but more importantly, inaccurate identification of the high-risk pollution sources and the priority metal pollutants in the source particles. When considering bioaccessibility of particle-bound heavy metals examined in this study, coal combustion products exhibited the highest carcinogenic and noncarcinogenic risks among all source particles, whereas cement particles would be the source with highest risk based on total metal content. As and Mn appeared to be the main drivers for the noncarcinogenic risks of source particles, while As, Ni and Cr were the major contributors to the carcinogenic risks of source particles, significantly different from those based on total contents. This research underlines the importance of incorporating bioaccessibility into health risk indexes of frequently occurring particle-bound heavy metals from specific air pollution sources, which will facilitate risk-based assessment of source contribution and hence effective source regulation of airborne PM.
快速的工业化和城市化导致空气中的颗粒物（PM）广泛受到污染，其中含有各种重金属，对人类健康产生不利影响。PM 的健康风险评估需要准确评估重金属在 PM 中的生物可利用性，而不是总含量。在这里，我们证明了在人体肺部颗粒典型保留时间内，肺液中颗粒结合态砷、铅、铬、锰、镉、铜、镍和锌的可浸提分数在来源不同的颗粒物（包括煤燃烧、生物质燃烧、扬尘、道路尘、建筑尘、水泥和土壤）之间存在显著差异。此外，重金属的生物可利用性，特别是在生物质燃烧、水泥和土壤颗粒中，强烈依赖于污染源，并且颗粒态铜、镍、铅和镉似乎是重金属生物可利用性来源依赖性的主要指标。使用颗粒结合态重金属的总浓度而不是生物可利用浓度不仅导致对源颗粒健康风险的高估，而且更重要的是，无法准确识别重金属生物可利用性的高风险污染源和源颗粒中的优先金属污染物。当考虑本研究中检测到的颗粒结合态重金属的生物可利用性时，煤燃烧产物在所有源颗粒中表现出最高的致癌和非致癌风险，而基于总金属含量，水泥颗粒则是风险最高的污染源。砷和锰似乎是源颗粒非致癌风险的主要驱动因素，而砷、镍和铬是源颗粒致癌风险的主要贡献者，这与基于总含量的结果显著不同。这项研究强调了将生物可利用性纳入特定空气污染来源的常见颗粒结合态重金属健康风险指数中的重要性，这将有助于基于风险的污染源贡献评估，从而有效地对空气中的 PM 进行源头调控。
