黄河三角洲潜在碳封存区域二氧化碳环境背景基线特征分析

Characteristics analysis of CO_(2)environmental background baseline for potential carbon sequestration sites in Yellow River Delta

大规模封存CO_(2)可能会发生泄漏并侵入浅地表造成环境影响。由于自然过程复杂变化,准确地掌握基线数值和分布对于近地表泄漏监测控制至关重要。采用移动设备沿预定路径进行流动现场监测和采样实验室测试分析结合的方法,对黄河三角洲潜在碳封存区域的大气、土壤气体组分、CO_(2)浓度进行监测分析,以确定基线值和分布。研究结果表明:①流动监测方法的CO_(2)浓度在3个不同层位的监测图中均显示出与固定监测点连续监测数据的一致性,呈现了监测区域CO_(2)浓度周期性波动的特征,同时,δ^(13)C_(CO_(2))与CO_(2)和O_(2)含量之间的关系显著,验证了流动监测方法的有效性;②查明了2条环境背景基线,第一条是δ^(13)C_(CO_(2))和δ^(13)C OC基线值,土壤δ^(13)C_(CO_(2))值为-14.35‰~-20.95‰,大气δ^(13)C_(CO_(2))值为-16.92‰~-19.89‰,土壤δ^(13)C OC值为-20.59‰~-24.79‰,这些数据反映了温带气候下土壤生物活动产生的C同位素值范围,第二条是大气与土壤CO_(2)浓度基线,大气CO_(2)浓度范围为219.20~416.4 ppm,土壤30 cm深度的CO_(2)浓度范围为1002.793~14808.13 ppm,土壤50 cm深度的CO_(2)浓度范围为1497.26~19658.59 ppm。研究通过确定黄河三角洲潜在封存场所浅地表环境CO_(2)浓度和同位素基线值,为未来实施大规模CO_(2)封存后的地面监测提供了对照基准和监测方案参考。

The large-scale sequestration of CO_(2)may result in leakage,which could intrude into the shallow subsurface and cause environmental impacts.Due to the complex changes of natural processes,accurately determining baseline values and distributions is crucial for monitoring and controlling near-surface leakage.This study utilized portable devices along scheduled path to conduct mobile and field monitoring and sampling laboratory test,and monitored and analyzed atmospheric and soil gas components and CO_(2)concentrations at potential sequestration sites in Yellow River Delta to determine baseline values and distributions.The results indicate that:①in the monitoring maps of three different layers,CO_(2)concentration data from the portable monitoring method are consistent with the continuous monitoring data from the fixed monitoring points,indicating the periodic fluctuation characteristics of the monitored CO_(2)concentration.Additionally,the statistically significant relationship betweenδ^(13)C_(CO_(2))and CO_(2)and O_(2)content confirms the reliability of the portable monitoring method.②Two environmental background baseline values are established.The first isδ^(13)C_(CO_(2))andδ^(13)C OC baseline,with the soilδ^(13)C_(CO_(2))isotope values of-14.35‰~-20.95‰,atmosphericδ^(13)C_(CO_(2))values of-16.92‰~-19.89‰,and soilδ^(13)C OC values of-20.59‰~-24.79‰.These values revealed the range of carbon isotope values produced by biological activity in temperate climates.The second is atmospheric and soil CO_(2)concentration baseline,with the atmospheric CO_(2)concentration of 219.20~416.4 ppm,soil CO_(2)concentrations at 30 cm depth of 1002.793~14808.13 ppm,and soil CO_(2)concentrations at 50 cm depth of 1497.26~19658.59 ppm.The environmental CO_(2)concentration and isotope baseline of shallow surface in potential carbon sequestration sites of Yellow River Delta were confirmed in this research,providing reference benchmarks and monitoring scheme recommendations for future surface monitoring after large-scale CO_(2)sequestration.