State Key Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
State Key Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; Collaborative Innovation Centre for Regional Environmental Quality, Tsinghua University, Beijing 100084, China.
Chemosphere. 2015 Sep;134:113-9. doi: 10.1016/j.chemosphere.2015.03.081. Epub 2015 May 15.
As one of the most important natural mercury (Hg) sources, soil release (emission to the atmosphere or leaching to soil water) depends on various factors, some of which can be affected by atmospheric deposition. We studied the effect of flue gas desulfurization gypsum (FGDG) addition on soil Hg release in a Masson pine (Pinus massoniana) forest in southwestern China. FGDG addition simulated atmospheric deposition of Ca(2+), SO4(2-) and Hg, which are commonly high in China. Results showed that Hg concentration in soil water decreased with the gypsum treatment, suggesting that the mobility of Hg in mineral soil was reduced. Moreover, the application of gypsum also seems to have decreased Hg emission from the soil, shown by the lower Hg contents in leaf tissues of ground vegetation in the treated plots than in the reference. Both Hg mobility in the soil and Hg emission to the atmosphere were decreased despite the additional Hg input from FGDG. The decreased DOC concentration in soil water and the elevated organic sulfur content in the soil Oe & Oa horizons were speculated to result in an enhanced capacity of surface soil to bind Hg, and thus to reduce Hg release from the soil. However, with the increasingly stringent control of particulate matter (PM) and sulfur dioxide (SO2) emissions in China, the deposition of Ca(2+) and SO4(2-) is expected to decrease, and their ability to inhibit soil Hg release is likely to decline in the future.
作为最重要的自然汞（Hg）源之一，土壤释放（向大气排放或淋滤到土壤水中）取决于多种因素，其中一些因素可能受大气沉降的影响。我们研究了烟气脱硫石膏（FGDG）添加对中国西南马尾松（Pinus massoniana）林土壤 Hg 释放的影响。FGDG 添加模拟了中国普遍存在的 Ca(2+)、SO4(2-)和 Hg 的大气沉降。结果表明，土壤水中 Hg 浓度随石膏处理而降低，表明矿物土壤中 Hg 的迁移性降低。此外，石膏的应用似乎也减少了土壤中 Hg 的排放，因为处理区的地面植被叶片组织中的 Hg 含量低于对照区。尽管 FGDG 增加了 Hg 的输入，但 Hg 在土壤中的迁移性和向大气中的排放都减少了。土壤水中 DOC 浓度降低，土壤 Oe 和 Oa 层中有机硫含量升高，推测这增强了表层土壤结合 Hg 的能力，从而减少了土壤中 Hg 的释放。然而，随着中国对颗粒物（PM）和二氧化硫（SO2）排放的控制日益严格，预计 Ca(2+)和 SO4(2-)的沉降量将减少，它们抑制土壤 Hg 释放的能力在未来可能会下降。
