福建省兴化湾大气重金属的干湿沉降

在兴化湾周围采集1年的大气颗粒物及降雨样品,测定分析了Cd,Pb,Zn和Cu 4种重金属的含量及其大气干湿沉降通量随季节的变化规律,并利用Pb同位素对大气颗粒物的来源进行了解析.结果表明:大气重金属的干沉降通量随季节变化不大,而湿沉降通量随季节变化明显.大气干沉降通量中,Cd,Cu随季节变化很小,而Pb,Zn有一定的季节变化,主要是因为降雨对大气颗粒物的去除作用.大气湿沉降通量中,所有重金属元素受降雨量影响显著,另外还与季节和风速有关.除Pb外,Cd,Zn和Cu的湿沉降通量均大于干沉降通量,说明湿沉降在大气对兴化湾重金属的输入过程中起主导作用.而Pb的输入则以颗粒态为主.根据Pb稳定同位素分析,兴化湾大气颗粒物中的重金属主要来源于工业活动. 

Atmospheric Deposition of Heavy Metals to Xinghua Bay, Fujian Province

Atmospheric dry and wet deposition samples were collected around Xinghua Bay in one year, and deposition fluxes of Cd, Pb, Zn and Ca in these samples were estimated. Season variations of Cd, Pb, Zn and Ca deposition fluxes were anaiyzed, and lead isotope was used to trace atmospheric particles source. The results show that seasonal variations of heavy metals dry deposition fluxes are small, but that of heavy metals wet deposition fluxes are obvious. Cd and Cu dry deposition fluxes hardly vary in different seasons, while Pb and Zn dry deposition fluxes vary with seasons because rainfall gets rid of some atmospheric particles. Atmospheric wet deposition fluxes of Cd, Pb, Zn and Cu are all influenced by rainfall, and they are related with season and wind speed. Atmospheric wet deposition fluxes of Cd, Zn and Cu are more than dry deposition fluxes of them, so atmospheric wet deposition of heavy metals to Xinghua Bay is more important. However, Pb deposition to Xinghua Bay is mainly particle-associated. According to the analysis-of stable lead isotope, particle-associated heavy metals in Xinghua Bay mainly come from industrial activity.