2000~2018年我国大气重金属沉降通量时空变化特征

大气沉降物中的重金属对土壤环境的影响不容忽视.为研究我国大气重金属（As、Cd、Cr、Cu、Hg、Ni、Pb和Zn）沉降通量现状及时空变化特征，基于中国知网和Web of Science数据库收集了2001~2021年公开发表的大气重金属沉降通量文献99篇，各重金属元素监测点718~1672个.采用Meta-analysis方法计算中国大气重金属沉降通量加权均值，运用亚组分析法研究了2000~2018年不同时期大气沉降通量时空变化，对比分析了农业农村区、城市区和工业区等不同类型区的组间差异.结果表明，我国大气重金属年沉降通量［mg·（m²·a）^-1］为：Zn （96.75）>Pb （23.37）>Cu （12.77）>Cr （11.04）>Ni （6.61）>As （2.97）>Cd （0.48）>Hg （0.05），2000~2018年沉降通量总体估计值高于1995~1998年英国乡村地区；工业区和城市区的沉降通量显著高于农业农村区，工业区大气重金属污染较为严重；长株潭地区As和Cd的沉降通量较高，东北地区、珠三角和华北平原大气重金属沉降通量较其它区域严重；近20年来Cd的年沉降通量均值在总体均值附近波动，无明显下降趋势；其中，城市区和农业农村区的Cd沉降通量呈增加趋势.本文建议结合区域产业结构特征建立分级分类分区的大气排放精准治理和风险管控措施，针对当前大气Cd沉降通量较大的问题实行更加严格的限制性措施.

Temporal and Spatial Variation Characteristics of Heavy Metal in Atmospheric Deposition in China from 2000 to 2018

Owing to the significant impact of heavy metals in atmospheric deposition on soil, clear knowledge on the present situation and temporal and spatial variation in fluxes of heavy metals in atmospheric deposition all around China is urgently needed. In this study, we collected 99 published papers on deposition fluxes of heavy metals from 2001 to 2021 based on the CNKI and Web of Science database and extracted 718 to 1672 monitoring points from these papers. The Meta-analysis method was used to calculate the weighted average of deposition fluxes of heavy metals, and the spatial-temporal characteristics in different periods from 2000 to 2018 were studied by subgroup analysis, which compared the differences between different types of areas, such as agricultural and rural areas and urban and industrial areas. The results showed that the annual fluxes of heavy metals in atmospheric depositionmg·(m²·a)^-1] in China were as follows:Zn (96.75)>Pb (23.37)>Cu (12.77)>Cr (11.04)>Ni (6.61)>As (2.97)>Cd (0.48)>Hg (0.05). Overall, the estimated value of deposition fluxes in China from 2000 to 2018 was higher than that of rural areas in England from 1995 to 1998. The deposition fluxes in industrial areas and urban areas were much higher than those in the agricultural and rural areas, especially the industrial areas where the heavy metal pollution was more serious. The deposition fluxes of As and Cd in the Changsha-Zhuzhou-Xiangtan area were relatively high, whereas the atmospheric deposition of heavy metals in Northeast China, the Pearl River Delta, and North China Plain was more serious than that in the other areas. In the past 20 years, the annual deposition fluxes of Cd fluctuated around the overall average, without an obviously declining trend, whereas the deposition fluxes of Cd in the urban, agricultural, and rural areas showed a trend of growth. These results suggested that precise and risk control measures of atmospheric emissions should be established based on the characteristics of regional industrial structure, which should cover all levels, all types, and all regions. In addition, more restrictive measures should be taken to solve the current problem caused by the higher deposition flux of Cd in atmospheric deposition.