极地雪冰中高氯酸盐的研究进展

REVIEW OF PERCHLORATE RESEARCH IN POLAR SNOW AND ICE

环境中普遍存在着自然条件下产生的高氯酸盐(ClO_(4)^(–)),其同位素组成的显著特征(如17O异常和/或36Cl正值)表明这些ClO_(4)^(–)很可能来自于大气平流层且臭氧(O3)参与了其形成过程。极地冰盖是保存大气来源ClO_(4)^(–)的天然档案,能够提供大气来源ClO_(4)^(–)的含量、空间分布、长时间尺度内的变化序列及不同历史时期的来源等信息。这些信息对于明确人类活动对大气来源ClO_(4)^(–)的影响,大气中产生ClO_(4)^(–)的机理,以及大气中ClO_(4)^(–)的产量与大气化学、环境条件之间的关系具有重要意义。在总结了极地雪冰中ClO_(4)^(–)的来源、含量水平、时间变化序列及大气中产生ClO_(4)^(–)的机理等方面的研究进展之后,提出今后应利用极地雪冰样品研究不同区域ClO_(4)^(–)的大气圈层(平流层、对流层)主要来源,并开展雪冰中ClO_(4)^(–)的沉积后过程研究,从而能够更好地理解ClO_(4)^(–)的大气化学过程,并获取大气中ClO_(4)^(–)的产量及其变化的真实信息。

Natural perchlorate(ClO_(4)^(−))is widespread in the natural environment.Its isotopic composition(e.g.,17O anomaly and/or positive 36Cl value)indicates that it probably comes from the stratosphere,and ozone(O_(3))is likely involved in its formation process.Polar ice sheets provide unique samples for the study of natural perchlorate.Snow and ice can provide chronological records indicating past perchlorate levels and spatial variability,and past and present primary perchlorate sources.This is important for understanding the influence of human activities on atmospheric perchlorate production and the relationships between atmospheric perchlorate production,atmospheric chemistry and environmental conditions.In this study,we reviewed the most recent findings in perchlorate research in polar snow,including findings on perchlorate sources,levels,trends,and production mechanism.We identified areas for future research.They include the dominant atmospheric(stratospheric or tropospheric)sources of perchlorate at different locations and the post-depositional processes of perchlorate in snow.Research results will contribute towards improving our understanding of the atmospheric chemistry of perchlorate and atmospheric perchlorate production and variability.