State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, 100084 Beijing, China.
School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 310000 Hangzhou China.
Environ Sci Technol. 2023 Mar 28;57(12):4775-4783. doi: 10.1021/acs.est.3c00926. Epub 2023 Mar 16.
As the Third Pole of the world, the Tibetan Plateau (TP) is sensitive to anthropogenic influences. Biomass combustion is one of the most important anthropogenic sources of mercury (Hg) emissions in the TP. However, due to the lack of knowledge about Hg emission characteristics and activity levels in the plateau, atmospheric Hg emissions from biomass combustion in the TP are under large uncertainties. Here, based on pilot-scale experiments, we found that particle-bound mercury (PBM; mean of 83.1-87.7 ng/m) occupied 17.93-49.31% of the total emitted Hg and the PBM δHg values (average -1.65‰ to -0.77‰) were significantly higher than those of the corresponding feeding biomass. The ΔHg values of total gaseous mercury and PBM were more negative (-0.08‰ to -0.05‰) than other anthropogenic emissions, providing unique isotopic fingerprints for this sector. Together with the investigated local activity levels, Hg emissions from biomass combustion reached 402 ± 74 kg/a, which were dozens of times higher than previous estimates. The emissions were characterized by conspicuous spatial heterogeneity, concentrated in the northern and central TP. Specialized Hg emissions and the Hg isotope fingerprint of local biomass combustion can aid in evaluating the influence of this sector on the fragile ecosystems of the TP.
作为世界第三极，青藏高原（TP）对人为影响很敏感。生物质燃烧是青藏高原人为汞（Hg）排放的最重要来源之一。然而，由于对高原上生物质燃烧 Hg 排放特征和活性水平缺乏了解，青藏高原生物质燃烧的大气 Hg 排放存在很大的不确定性。在这里，基于中试实验，我们发现颗粒态汞（PBM；均值为 83.1-87.7ng/m）占总排放 Hg 的 17.93-49.31%，并且 PBM δHg 值（平均-1.65‰至-0.77‰）明显高于相应的给料生物质。总气态汞和 PBM 的 ΔHg 值比其他人为排放更负（-0.08‰至-0.05‰），为该部门提供了独特的同位素特征。再加上调查到的当地活性水平，生物质燃烧的 Hg 排放量达到了 402±74kg/a，是之前估计值的数十倍。排放具有明显的空间异质性，集中在青藏高原的北部和中部。当地生物质燃烧的专门化 Hg 排放和 Hg 同位素特征有助于评估该部门对青藏高原脆弱生态系统的影响。
