Zota Ami R, Willis Robert, Jim Rebecca, Norris Gary A, Shine James P, Duvall Rachelle M, Schaider Laurel A, Spengler John D
Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA.
J Air Waste Manag Assoc. 2009 Nov;59(11):1347-57. doi: 10.3155/1047-3289.59.11.1347.
Atmospheric dispersion of particles from mine waste is potentially an important route of human exposure to metals in communities close to active and abandoned mining areas. This study assessed sources of mass and metal concentrations in two size fractions of respirable particles using positive matrix factorization (U.S. Environmental Protection Agency [EPA] PMF 3.0). Weekly integrated samples of particulate matter (PM) 10 microm in aerodynamic diameter or less (PM10) and fine PM (PM2.5, or PM <2.5 microm in aerodynamic diameter) were collected at three monitoring sites, varying distances (0.5-20 km) from mine waste piles, for 58 consecutive weeks in a former lead (Pb) and zinc (Zn) mining region. Mean mass concentrations varied significantly across sites for coarse PM (PM10-PM2.5) but not PM2.5 particles. Concentrations of Pb and Zn significantly decreased with increasing distance from the mine waste piles in PM10-PM2.5 (P < 0.0001) and PM2.5 (P < 0.0005) fractions. Source apportionment analyses deduced five sources contributing to PM2.5 (mobile source combustion, secondary sulfates, mine waste, crustal/soil, and a source rich in calcium [Ca]) and three sources for the coarse fraction (mine waste, crustal/soil, and a Ca-rich source). In the PM2.5 fraction, mine waste contributed 1-6% of the overall mass, 40% of Pb, and 63% of Zn. Mine waste impacts were more apparent in the PM10-PM2.5 fraction and contributed 4-39% of total mass, 88% of Pb, and 97% of Zn. Percent contribution of mine waste varied significantly across sites (P < 0.0001) for both size fractions, with highest contributions in the site closest to the mine waste piles. Seasonality, wind direction, and concentrations of the Ca-rich source were also associated with levels of ambient aerosols from the mine waste source. Scanning electron microscopy results indicated that the PMF-identified mine waste source is mainly composed of Zn-Pb agglomerates on crustal particles in the PM10-PM2.5 fraction. In conclusion, the differential impacts of mine waste on respirable particles by size fraction and location should be considered in future exposure evaluations.
来自矿山废弃物的颗粒物在大气中的扩散，可能是活跃和废弃矿区附近社区居民接触金属的一条重要途径。本研究使用正矩阵因子分解法（美国环境保护局[EPA] PMF 3.0）评估了可吸入颗粒物两个粒径级分中质量和金属浓度的来源。在一个 former铅（Pb）和锌（Zn）矿区，在距矿山废弃物堆不同距离（0.5 - 20千米）的三个监测点，连续58周每周采集一次空气动力学直径小于或等于10微米的颗粒物（PM10）和细颗粒物（PM2.5，即空气动力学直径小于2.5微米的颗粒物）的综合样本。粗颗粒物（PM10 - PM2.5）的平均质量浓度在各监测点间差异显著，但PM2.5颗粒物的平均质量浓度无显著差异。在PM10 - PM2.5（P < 0.0001）和PM2.5（P < 0.0005）级分中，Pb和Zn的浓度随距矿山废弃物堆距离的增加而显著降低。源解析分析推断出对PM2.5有贡献的五个来源（移动源燃烧、二次硫酸盐、矿山废弃物、地壳/土壤以及富含钙[Ca]的来源）和对粗粒径级分有贡献的三个来源（矿山废弃物、地壳/土壤以及富含Ca的来源）。在PM2.5级分中，矿山废弃物占总质量的1 - 6%、Pb的40%和Zn的63%。矿山废弃物的影响在PM10 - PM2.5级分中更为明显，占总质量的4 - 39%、Pb的88%和Zn的97%。对于两个粒径级分，矿山废弃物的贡献率在各监测点间差异显著（P < 0.0001），在距离矿山废弃物堆最近的监测点贡献率最高。季节性、风向以及富含Ca来源的浓度也与来自矿山废弃物源的环境气溶胶水平相关。扫描电子显微镜结果表明，PMF识别出的矿山废弃物源在PM10 - PM2.5级分中主要由地壳颗粒上的Zn - Pb团聚体组成。总之，在未来的暴露评估中应考虑矿山废弃物对不同粒径级分和不同位置的可吸入颗粒物的不同影响。
