Department of Environmental Science and Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China.
Environ Sci Pollut Res Int. 2019 Nov;26(33):34357-34367. doi: 10.1007/s11356-019-06366-6. Epub 2019 Nov 13.
To investigate the acid-extractable heavy metals in fine particulate matter (PM) over Xi'an, China, 24-h PM samples were collected every 3 days from December 2015 through November 2016. The bioavailable fraction, termed here the bioavailability index (BI), of PM-bound metal (As, Ba, Cd, Co, Cu, Mn, Ni, Pb, Ti, V, and Zn) and potential influencing factors, including relative humidity, temperature, air pressure, wind speed, visibility, PM, and SO concentrations, were assessed in this study. The annual average PM concentration was 50.6 ± 35.6 μg m, 1.5 times higher than the Chinese national secondary standard. Zn, Ti, and As were the most abundant elements of those analyzed in the PM samples, accounting for 72.1% of total quantity. The seasonal variations and enrichment factor analysis of heavy metals revealed that coal combustion in winter was a crucial source of Pb, Co, Cu, and Zn; and dust resuspension in spring contributed considerable Mn, Ti, and V. The acid-extractable fractions of the measured metals varied. Pb, Cu, Mn, and Zn exhibited relatively high acid-extractable concentrations and BI values. Pb was mostly in the acid-extractable fraction in PM, with a mean BI value of 66.7%, the highest in summer (69.8%) and lowest in winter (63.7%). Moreover, the BIs of PM-bound heavy metals were inversely related to temperature and wind speed, whereas positively correlated with relative humidity, SO, and PM concentration in this study. This study assessed the seasonal distribution and meteorological influence of acid-extractable heavy metals, providing a deeper understanding of atmospheric heavy metal pollution in Xi'an, China.
为了研究中国西安细颗粒物（PM）中可酸提取的重金属，本研究于 2015 年 12 月至 2016 年 11 月间，每隔 3 天采集了 24 小时 PM 样本。本研究评估了 PM 结合金属（As、Ba、Cd、Co、Cu、Mn、Ni、Pb、Ti、V 和 Zn）的生物可利用部分，即生物有效性指数（BI），以及潜在影响因素，包括相对湿度、温度、气压、风速、能见度、PM 和 SO 浓度。研究结果表明，年平均 PM 浓度为 50.6±35.6μg/m，是中国国家二级标准的 1.5 倍。在所分析的 PM 样本中，Zn、Ti 和 As 是最丰富的元素，占总量的 72.1%。重金属的季节性变化和富集因子分析表明，冬季的煤炭燃烧是 Pb、Co、Cu 和 Zn 的主要来源；而春季的扬尘则对 Mn、Ti 和 V 的贡献较大。测量金属的可酸提取部分差异较大。Pb、Cu、Mn 和 Zn 表现出相对较高的可酸提取浓度和 BI 值。Pb 主要存在于 PM 的可酸提取部分，平均 BI 值为 66.7%，夏季最高（69.8%），冬季最低（63.7%）。此外，本研究中 PM 结合重金属的 BI 值与温度和风速呈负相关，而与相对湿度、SO 和 PM 浓度呈正相关。本研究评估了可酸提取重金属的季节性分布和气象影响，为深入了解中国西安大气重金属污染提供了依据。
