Boron (B) concentrations and isotopic compositions were measured in the precipitations of Guiyang, China for one year. Most precipitation samples have boron concentrations of from 2.1 to 4.8 ng ml−1, and δ11B values of from +2.0‰ to +30.0‰. Boron concentrations and δ11B values of heavy rain samples are generally higher than those of light rain and snow samples. Anthropogenic inputs provided most of the SO42− and NO3−, which were predominant ions in the precipitation. The major cation Ca2+ in the precipitation was mainly originated from local dust.
The total boron in precipitation from Guiyang is explained by the mixing model of three boron sources. Assuming a δ11B value of +45‰ for the seawater component, contributions of marine source, organic matter and biomass combustion, and coal combustion were estimated to be 32%, 49%, and 19%, respectively to the total boron in Guiyang precipitations. The coal combustion and biomass (and/or organic matter) combustion showed different contributions of boron to the rainwaters in different seasons, the former in cold season while the latter in summer season had a more marked influence on the chemical and isotopic composition of the rainwater. The largest contribution of seawater-originated boron was observed for the heavy rain samples, which was up to 68%.
This study indicates that the atmospheric environment of Guiyang city was strongly influenced by human activities, and boron isotopic composition is of great sensitivity to anthropogenic sources and can be a powerful technique to trace various sources of atmospheric emissions and even their origins.
| Publication name |
Atmospheric Environment, Volume 44, Issue 34, November 2010, Pages 4165-4171 |
| Author(s) |
Zhao, Zhi-Qi; Liu, Cong-Qiang |
| Corresponding author |
LIU Congqiang
liucongqiang@vip.skleg.cn Chinese Acad Sci, Inst Geochem, State Key Lab Environm Geochem, Guanshui Rd 46, Guiyang 550002, Peoples R China |
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