Does wet precipitation represent local and regional atmospheric transportation by perfluorinated alkyl substances?
Does wet precipitation represent local and regional atmospheric transportation by perfluorinated alkyl substances?
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DOI：
10.1016/j.envint.2013.02.005
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发表时间：
2013-05
影响因子：
11.8
通讯作者：
S. Taniyasu;N. Yamashita;Hyo-Bang Moon;K. Kwok;P. Lam;Y. Horii;G. Petrick;K. Kannan
中科院分区：
文献类型：
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作者：
S. Taniyasu;N. Yamashita;Hyo-Bang Moon;K. Kwok;P. Lam;Y. Horii;G. Petrick;K. Kannan
全氟烷基物质(PFAS)广泛存在于环境中，包括偏远的海洋地区。将全氟辛烷磺酸运往偏远海洋地点的方式是一个具有相当大科学意义的主题。评估在覆盖大陆、沿海和开阔海洋的区域收集的湿降水样本(即降雨和雪)中全氟辛烷磺酸的分布，将使人们不仅能够了解全氟辛烷磺酸的全球迁移，而且能够了解其区域迁移。然而，必须审查湿降水矩阵的代表性和适宜性，以便就运输全氟辛烷磺酸得出结论。在这项研究中，我们收集了日本几个地点的湿降水样本，包括降雨量、地表积雪和雪核，以阐明这些矩阵是否适合描述PFASs的局部和区域输送。在一次降雨事件中，在不同时间间隔收集的雨水显示，在前1毫米的沉降量中，PFASs的通量很高。通过湿法沉积的PFAS的清除率随PFAS的碳链长度而不同。在大陆(日本筑波)和开阔海域(太平洋，距日本海岸1000公里)测得的全氟辛烷磺酸的沉积通量相似，约为每平方米几纳克。从同一地点采集的“新鲜”雪样和“陈化”雪样(在地面上存放几天)的全氟辛烷磺酸图谱差别很大。新沉积的雪代表了当前全氟辛烷磺酸的大气轮廓，而老化的雪样反映了大气中本地来源的全氟辛烷磺酸的封存。全氟辛烷磺酸剖面中的沉积后修饰很明显，表明全氟辛烷磺酸在冰雪表面发生了反应。在雪面上，前驱体化学物质，如含氟调聚物醇，明显地转化为全氟烷基羧酸盐。雪芯已被用来评估偏远环境中全氟辛烷磺酸污染的时间趋势。从一个深达7.7米的岩心收集的不同深度的雪，在山上。日本Tateyama(2450m)表层的全氟辛烷磺酸浓度最高，除全氟丁磺酸(PFBS)外，大多数全氟辛烷磺酸的浓度随着深度的增加而降低。对雪核的分析表明，在雪的融化和冻结循环之后，高水溶性全氟辛烷磺酸如全氟辛烷磺酸的下移是明显的。
Perfluorinated alkyl substances (PFASs) have been found widely in the environment including remote marine locations. The mode of transport of PFASs to remote marine locations is a subject of considerable scientific interest. Assessment of distribution of PFASs in wet precipitation samples (i.e., rainfall and snow) collected over an area covering continental, coastal, and open ocean will enable an understanding of not only the global transport but also the regional transport of PFASs. Nevertheless, it is imperative to examine the representativeness and suitability of wet precipitation matrixes to allow for drawing conclusions on the transport PFASs. In this study, we collected wet precipitation samples including rainfall, surface snow, and snow core from several locations in Japan to elucidate the suitability of these matrixes for describing local and regional transport of PFASs. Rain water collected at various time intervals within a single rainfall event showed high fluxes of PFASs in the first 1-mm deposition. The scavenging rate of PFASs by wet deposition varied depending on the fluorocarbon chain length of PFAS. The depositional fluxes of PFASs measured for continental (Tsukuba, Japan) and open ocean (Pacific Ocean, 1000km off Japanese coast) locations were similar, on the order of a few nanograms per square meter. The PFAS profiles in “freshly” deposited and “aged” (deposited on the ground for a few days) snow samples taken from the same location varied considerably. The freshly deposited snow represents current atmospheric profiles of PFASs, whereas the aged snow sample reflects sequestration of local sources of PFASs from the atmosphere. Post-depositional modifications in PFAS profiles were evident, suggesting reactions of PFASs on snow/ice surface. Transformation of precursor chemicals such as fluorotelomer alcohols into perfluoroalkylcarboxylates is evident on snow surface. Snow cores have been used to evaluate time trends of PFAS contamination in remote environments. Snow collected at various depths from a core of up to 7.7m deep, at Mt. Tateyama (2450m), Japan, showed the highest concentrations of PFASs in the surface layer and the concentrations decreased with increasing depth for most PFASs, except for perfluorobutanesulfonate (PFBS). Downward movement of highly water soluble PFASs such as PFBS, following melting and freezing cycles of snow, was evident from the analysis of snow core.