Liang Jian, Jiang Tao, WeiI Shi-Qiang, Lu Song, Yan Jin-Long, Wang Qi-Lei, Gao Jie
Huan Jing Ke Xue. 2015 Mar;36(3):888-97.
This study aimed at evaluating the variability of the optical properties including UV-Vis and fluorescence characteristics of dissolved organic matter (DOM) from rainwater in summer and winter seasons. UV-Vis and fluorescence spectroscopy, together with Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model and fire events map, were conducted to characterize DOM and investigate its sources and contributions. The results showed that as compared with aquatic and soil DOM, rainwater DOM showed similar spectral characteristics, suggesting DOM in precipitation was also an important contributor to DOM pool in terrestrial and aquatic systems. The concentrations of DOC in rainwater were 0.88-12.80 mg x L(-1), and the CDOM concentrations were 3.17-21.11 mg x L(-1). Differences of DOM samples between summer and winter were significant (P < 0.05). In comparison to summer, DOM samples in winter had lower molecular weight and aromaticity, and also lower humification. Input of DOM in winter was predominantly derived from local and short-distance distances, while non-special scattering sources were identified as the main contributors in summer. Although absorption and fluorescence spectroscopy could be used to identify DOM composition and sources, there were obvious differences in spectra and sources analysis between rainwater DOM and the others from other sources. Thus, the classic differentiation method by "allochthonous (terrigenous) and autochthonous (authigenic)" is possibly too simple and arbitrary for characterization of DOM in rainwater.
本研究旨在评估夏季和冬季雨水中溶解有机物（DOM）的光学特性（包括紫外-可见和荧光特性）的变异性。采用紫外-可见和荧光光谱法，结合混合单粒子拉格朗日积分轨迹（HYSPLIT）模型和火灾事件地图，对DOM进行表征，并研究其来源和贡献。结果表明，与水生和土壤DOM相比，雨水中的DOM具有相似的光谱特征，这表明降水中的DOM也是陆地和水生系统中DOM库的重要贡献者。雨水中溶解有机碳（DOC）的浓度为0.88 - 12.80 mg·L⁻¹，有色溶解有机物（CDOM）的浓度为3.17 - 21.11 mg·L⁻¹。夏季和冬季DOM样本之间的差异显著（P < 0.05）。与夏季相比，冬季的DOM样本分子量和芳香性较低，腐殖化程度也较低。冬季DOM的输入主要来自本地和短距离，而夏季的主要贡献者则是非特定散射源。尽管吸收和荧光光谱可用于识别DOM的组成和来源，但雨水中的DOM与其他来源的DOM在光谱和来源分析上存在明显差异。因此，用“外源（陆源）和内源（自生）”进行经典区分的方法，可能过于简单和随意，无法用于表征雨水中的DOM。
