| Chengdu Plain is the most important grain production area and high-speed economic development area in Southwest China.With the development of urbanization and agricultural intensification,the region has formed a more orderly transition structure of population and industry circle,and heavy metal deposition in the atmosphere is intense,but its intensity and temporal and spatial variation law are not clear.Therefore,this study takes the transition zone of urban and rural areas in the west of Chengdu Plain as the research area,and carries out a one-year continuous monitoring of heavy metal deposition in the air from June 2018 to may 2019,which clarifies the intensity,temporal and spatial variation characteristics and influencing factors of heavy metal deposition in the West of Chengdu Plain,so as to provide theoretical basis for the prevention and control of heavy metal pollution in the water,soil and air in the agricultural and economic tourism development area The results are as follows:（1）The annual fluxes of soluble precipitation of Cr,Cu,Zn,Cd,and Pb in the study area are 1.943,1.972,36.603,0.653,and 1.196 mg m-2 yr-1,respectively;the annual fluxes in the particulate state are 12.197,6.670,90.571,0.810,12.117 mg m-2 yr-1;the total annual deposition fluxes are 14.140,8.642,127.174,1.463,13.312 mg m-2 yr-1.All samples in the study area are mainly granular deposition,accounting for 55.38%～91.02%of the total deposition.（2）The precipitation of heavy metals in the atmosphere in the study area shows a certain difference in time.Soluble sedimentation flux basically showed the highest trend in summer,followed by autumn and winter,and the lowest trend in spring（P<0.05）;granular sedimentation flux showed the highest trend in winter,followed by autumn,and the lowest trend in summer and spring（P<0.05）;The total settlement showed the highest trend of Cr and Zn in winter,followed by autumn,and the lowest in summer and spring（P<0.05）;Cd and Pb showed the highest in summer,followed by winter and autumn,and the lowest trend in spring（P<0.05）;Cu The trend was highest in winter,followed by summer and autumn,and lowest in spring（P<0.05）.Due to policy-related emission reduction measures,spring was significantly lower than other seasons.（3）The spatial variation of heavy metal deposition in the atmosphere in the study area shows some differences.The fluxes of forest areas（Jiguanshan,Huaiyuan）in soluble sedimentation are higher than those in other areas,where Cr and Zn are greater than forest areas,greater than agricultural areas,greater than comprehensive areas,and urban areas（P<0.05）.The forest area is larger than the comprehensive area,and the urban area is larger than the agricultural area（P<0.05）.The integrated area（Yuantong）and urban area（Mingzhu）are the areas with the highest fluxes in the granular settlement,and Cr,Cd,and Pb are all integrated areas.The urban area is larger than the forest area and larger than the agricultural area（P<0.05）,Cu and Zn all show comprehensive areas,and the urban area is larger than the agricultural area and larger than the forest area（P<0.05）.In general,the total settlement flux of the study area gradually decreased along the transition zone of urban area,comprehensive area-forest area-agricultural area.（4）The annual flux of total heavy metal deposition in different atmospheres is ranked as:Zn>Cr>Pb>Cu>Cd.Among them,the deposition of Zn,Cd,and Pb elements is relatively high compared to other similar regions,which needs to be paid attention to in related fields. |
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