State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, Xiamen 361102, China; Guangxi Colleges and Universities Key Laboratory of Environmental Protection, School of Environment, Guangxi University, Nanning 530004, China.
State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, Xiamen 361102, China.
Environ Pollut. 2016 Jul;214:822-830. doi: 10.1016/j.envpol.2016.04.059. Epub 2016 May 5.
Seawater flue gas desulfurization (SFGD) systems are commonly used to remove acidic SO2 from the flue gas with alkaline seawater in many coastal coal-fired power plants in China. However, large amount of mercury (Hg) originated from coal is also transferred into seawater during the desulfurization (De-SO2) process. This research investigated Hg isotopes in seawater discharged from a coastal plant equipped with a SFGD system for the first time. Suspended particles of inorganic minerals, carbon residuals and sulfides are enriched in heavy Hg isotopes during the De-SO2 process. δ(202)Hg of particulate mercury (PHg) gradually decreased from -0.30‰ to -1.53‰ in study sea area as the distance from the point of discharge increased. The results revealed that physical mixing of contaminated De-SO2 seawater and uncontaminated fresh seawater caused a change in isotopic composition of PHg isotopes in the discharging area; and suggested that both De-SO2 seawater and local background contributed to PHg. The impacted sea area predicted with isotopic tracing technique was much larger than that resulted from a simple comparison of pollutant concentration. It was the first attempt to apply mercury isotopic composition signatures with two-component mixing model to trace the mercury pollution and its influence in seawater. The results could be beneficial to the coal-fired plants with SFGD systems to assess and control Hg pollution in sea area.
海水烟气脱硫（SFGD）系统在中国许多沿海燃煤电厂中被广泛用于用碱性海水去除烟道气中的酸性 SO2。然而，大量来自煤炭的汞（Hg）也在脱硫（De-SO2）过程中转移到海水中。本研究首次调查了沿海工厂配备的 SFGD 系统排放的海水中的汞同位素。在 De-SO2 过程中，无机矿物质、碳残留物和硫化物的悬浮颗粒富含重汞同位素。研究海域中，随着与排放点距离的增加，颗粒态汞（PHg）的 δ(202)Hg 逐渐从-0.30‰降低至-1.53‰。结果表明，受污染的 De-SO2 海水与未受污染的新鲜海水的物理混合导致排放区 PHg 同位素同位素组成发生变化；表明 De-SO2 海水和当地背景都对 PHg 有贡献。同位素示踪技术预测的受影响海域比简单比较污染物浓度所得到的结果要大得多。这是首次应用汞同位素组成特征和双组分混合模型来追踪海水中的汞污染及其影响。研究结果有助于配备 SFGD 系统的燃煤电厂评估和控制海域中的汞污染。
