太原市干湿沉降中PAHs的特征来源及风险评价

发布时间：2019-06-27 15:25

【摘要】：大气干湿沉降是大气中污染物去除的主要方式。本研究采集了太原市2013年8月到2014年10月期间的干沉降和雨水样品,分析和报道了其中16种优控PAHs水平,探讨了干沉降和雨水中PAHs分布特征和影响因素,并进一步估算了太原市PAHs干沉降和雨水通量及生态风险,为了解太原市大气PAHs干沉降和雨水去除机制和环境地球化学效应提供基础数据。主要得出以下结论:(1)干沉降中PAHs水平为19.61~61.91μg/g,均值为33.85μg/g。2~3环、4环和5~6环PAHs所占百分比分别为54.56%、29.12%和16.32%。(2)湿沉降(雨水)中总PAHs(溶解态+颗粒态)水平为965.97~44393.80 ng/L,溶解性PAHs为350.90~10704.0 ng/L,颗粒态PAHs为332.45~35532.68 ng/L。颗粒态PAHs占总PAHs的67.28%。2~3环PAHs在总PAHs、溶解态PAHs、颗粒态PAHs中所占百分比分别为67.56%、70.97%、65.54%。(3)PAHs干湿沉降通量为6560.90~16289.60 ng/(m2·d),其中干沉降通量为4196.4~14769.8 ng/(m2·d),湿沉降沉降通量为319.98~10608.0 ng/(m2·d)。大气干沉降是太原市大气PAHs的主要去除方式。据此,2013年太原市大气PAHs干湿沉降总量为31.57t,其中干沉降为23.90 t,湿沉降为7.67 t。(4)BaP的毒性当量浓度分析显示,干沉降中16种PAHs的TEQ浓度范围为0.86~2.80μg/g,雨水中16种PAHs的TEQ浓度范围为26.94~2456.28 ng/L。值得注意的是,所有雨水样品中BaP毒性当量浓度均高于国家地表水相关标准限值,具有较高的生态风险。生态效应区间法对干沉降中PAHs进行风险评价发现处于中等或较高生态风险。(5)PAHs特征比值显示干湿沉降中PAHs主要来自燃煤和石油源。主成分分析显示燃煤、机动车尾气、炼焦是太原市干湿沉降中PAHs三个主要来源。
[Abstract]:Atmospheric dry and wet deposition is the main way to remove pollutants from the atmosphere. In this study, dry deposition and Rain Water samples from August 2013 to October 2014 in Taiyuan City were collected, 16 kinds of optimized PAHs levels were analyzed and reported, the distribution characteristics and influencing factors of PAHs in dry deposition and Rain Water were discussed, and the dry deposition and Rain Water flux and ecological risk of PAHs in Taiyuan were further estimated, which provided basic data for understanding the mechanism of atmospheric PAHs dry deposition and the removal mechanism of Rain Water and environmental geochemistry effects in Taiyuan. The main conclusions are as follows: (1) the level of PAHs in dry deposition is 19.61 ~ 61.91 渭 g / g, the mean value is 33.85 渭 g / g 路2, the percentages of PAHs in 4 rings and 5 鈮，

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