Université de Toulon, Aix Marseille Univ, CNRS, IRD, MIO - CS 60584, Toulon, 83041 CEDEX 9, France.
Department of Environmental and Earth Sciences, Faculty of Science, The Islamic University-Gaza, P.O Box 108, 00970, Gaza, Palestinian Territory.
Environ Sci Pollut Res Int. 2021 Jul;28(27):36707-36726. doi: 10.1007/s11356-021-13265-2. Epub 2021 Mar 11.
Organic matter has an important role in biogeochemistry in aquatic environments. This study investigated impact of suspended particulate organic matter (SPOM) on fluorescence signal of mixtures of three water types (river water RW, sea water SW, effluent wastewater WW) using fluorescence (excitation-emission matrix, EEM) spectroscopy and parallel factor analysis (PARAFAC) and multilinear regression. Four irradiation experiments (Expt-1, Expt-2, Expt-3, and Expt-4) were conducted during different times of the year ( two in autumn, one in winter, and one in spring season). Samples were exposed to natural sunlight on laboratory rooftop in University of Toulon, France, with another set of samples kept in dark as control samples. Three component (C1, C2, C3) model was validated by split-half and Concordia from the whole EEM dataset of all irradiation experiments. No protein-like fluorophores was found. The study revealed the effect of SPOM presence/absence on fluorescence signal of DOM and on resulting parameters of multilinear regression MLR model and kinetic constant of these MLR parameters. Kinetic constant (k) for all MLR coefficients was in order of greatness as Expt-1 (SPOM of WW only in mixtures) > Expt-3 (SPOM of SW only in mixtures) > Expt-2 (SPOM of RW only in mixtures)> Expt-4 (SPOM of RW + SW + WW in mixtures) indicating that SPOM of WW is the most resistant to photodegradation. For dark control samples, only relative standard deviation RSD could be calculated from dataset. RSD values for C3 were the highest indicating its chaotic variations, and the lowest RSD values were found for both C1 and C2 for all experiments. Statistical differences has been found between control and irradiated experiments. These models developed in this study can be used to predict fluorescence signal of anthropogenic effluent DOM during its transport in river systems to coastal zone.
有机物在水生环境的生物地球化学中具有重要作用。本研究使用荧光（激发-发射矩阵，EEM）光谱和平行因子分析（PARAFAC）和多线性回归，调查了悬浮颗粒有机物（SPOM）对三种水型（河水 RW、海水 SW、废水 WW）混合物荧光信号的影响。在一年中的不同时间进行了四个辐照实验（实验 1、实验 2、实验 3 和实验 4）（两个在秋季，一个在冬季，一个在春季）。样品在法国土伦大学的实验室屋顶上暴露在自然光下，另一组样品保存在黑暗中作为对照样品。通过分割半和协和从所有辐照实验的整个 EEM 数据集验证了三组分（C1、C2、C3）模型。未发现类蛋白荧光团。该研究揭示了 SPOM 的存在/不存在对 DOM 荧光信号以及由此产生的多线性回归（MLR）模型参数和这些 MLR 参数的动力学常数的影响。所有 MLR 系数的动力学常数（k）的大小顺序为实验 1（仅 WW 的 SPOM 存在于混合物中）>实验 3（仅 SW 的 SPOM 存在于混合物中）>实验 2（仅 RW 的 SPOM 存在于混合物中）>实验 4（RW+SW+WW 的 SPOM 存在于混合物中），表明 WW 的 SPOM 对光降解的抵抗力最强。对于黑暗对照样品，只能从数据集计算相对标准偏差（RSD）。C3 的 RSD 值最高，表明其变化混乱，所有实验中 C1 和 C2 的 RSD 值最低。在对照和辐照实验之间发现了统计学差异。本研究中开发的这些模型可用于预测河流系统向沿海区输送人为废水 DOM 的荧光信号。
