利用石生苔藓中硫同位素示踪大气硫源的变化规律

Sulfur Isotope of Epilithic Mosses to Trace Variation of Atmospheric Sulfur Sources

为探讨石生苔藓硫同位素组成特征对区域性大气硫源的指示作用,连续两年采集鄱阳湖生态经济区内的石生苔藓样品,测定δ34S值;并结合已有的雨水、煤的硫同位素值等相关研究数据进行对比分析。样品δ34S值均偏正,平均为+4.9‰,取值范围为+1.9‰^+9.6‰;石生苔藓δ34S值与空气中SO2浓度呈负相关关系;南昌、抚州两市苔藓δ34S值的取值范围与其对应城市大气降水δ34 S值的变化区间相接近;研究区内土壤相对富集重硫,且土壤中可溶性硫主要受大气硫沉降影响。结果表明,石生苔藓的硫同位素组成对区域性大气硫源具有指示意义,鄱阳湖生态经济区大气硫沉降的硫源主要来自人为成因硫和生物成因硫,可能还有远距离传输硫等其他硫源的影响。

The variation of atmospheric sulfur sources in Poyang Lake Eco-economic Region was explored by sulfur isotopes in epilithic mosses which collected from the research area during 2012 to 2013,and then compared it with the existing researchδ34S values of rain and coal.The results showed that all of theδ34S values of epilithic mosses performed as positive value at a range of 1.9‰to 9.6‰,the average was 4.9‰.It was found a significant negative correlation existed between theδ34S values of epilithic mos-ses（x）and atmospheric SO2concentration（y）（y=-82.61x＋7.63,R2=0.85）.Theδ34S values of epilithic mosses in Nanchang and Fuzhou were close to theδ34S values of its corresponding city＇s atmospheric precipitation.Theδ34 S values of soil total sulfur were higher than that of epilithic mosses,while the latter was closer to theδ34S values of soil soluble sulfur,showing that the soil enriched more heavy sulfur sources and soluble sulfur in the rhizosphere soil may be mainly derived from atmospheric sulfur deposition.The results indicated that the atmospheric sulfur source in Poyang Lake Ecoeconomic Region were mainly affected by coal burning and other human activities as well as biogenic sulfur,besides,long-distance transmission sulfur from northerly air masses may be another sulfur source of atmospheric sulfur deposition in this area.