École de technologie supérieure, University of Quebec, 1100 Notre-Dame Street West, Montreal QC H3C 1K3, Canada.
École de technologie supérieure, University of Quebec, 1100 Notre-Dame Street West, Montreal QC H3C 1K3, Canada.
Environ Pollut. 2020 Oct;265(Pt A):115052. doi: 10.1016/j.envpol.2020.115052. Epub 2020 Jun 22.
Dissolved organic matter (DOM) is recognized as a good indicator of water quality as its concentration is influenced by land use, rainwater, windborne material and anthropogenic activities. Recent technological advances make it possible to characterize fluorescent dissolved organic matter (FDOM), the fraction of DOM that fluoresces. Among these advances, portable fluorometers and benchtop fluorescence excitation and emission spectroscopy coupled with a parallel factor analysis (EEM-PARAFAC) have shown to be reliable. Despite their rising popularity, there is still a need to evaluate the extent to which these techniques can assess DOM dynamics at the watershed scale. We compare the performance of in-situ measurements of FDOM with laboratory measurements of fluorescence spectroscopy within the context of two distinct glacierized watersheds in Peru. Glacierized watersheds represent unique testing environments with contrasting DOM conditions, flowing from pristine, vegetation-free headwaters through locations with obvious anthropogenic influences. We used an in-situ fluorometer and a portable multimeter to take 38 measurements of FDOM, pH and turbidity throughout the two catchments. Additionally, samples were analyzed in the laboratory using the EEM-PARAFAC method. Results were compared to dissolved organic carbon (DOC) measurements using standard high-temperature catalytic oxidation. Our results show that the three techniques together were able to capture the DOM dynamics for both studied watersheds. Taken individually, all three methods allowed detection of the watershed DOM main points of sources but in a more limited way. Due to the narrow bandwidth of the portable fluorometer used in the study, FDOM measurements were almost non-detectable to protein-like substances. Indeed, the more demanding EEM-PARAFAC was able to both differentiate between potential sources of DOM and provide an estimate of relative concentrations of different organic components. Finally, similar to FDOM but to a lesser extent, the DOC measurements showed some limits where protein-like substances make up most of the DOM composition.
溶解有机物（DOM）被认为是水质的良好指标，因为其浓度受土地利用、雨水、风载物质和人为活动的影响。最近的技术进步使得对荧光溶解有机物（FDOM）进行特征描述成为可能，FDOM 是 DOM 中具有荧光的部分。在这些进步中，便携式荧光计和台式荧光激发和发射光谱学与平行因子分析（EEM-PARAFAC）的结合已被证明是可靠的。尽管它们越来越受欢迎，但仍需要评估这些技术在多大程度上可以评估流域范围内的 DOM 动态。我们比较了在秘鲁两个不同冰川流域的背景下，FDOM 的现场测量与荧光光谱实验室测量的性能。冰川流域具有独特的测试环境，具有不同的 DOM 条件，从原始的、无植被的源头流到明显有人为影响的位置。我们使用现场荧光计和便携式多用表在两个流域内进行了 38 次 FDOM、pH 和浊度的测量。此外，还使用 EEM-PARAFAC 方法在实验室中对样品进行了分析。结果与使用标准高温催化氧化法测量的溶解有机碳（DOC）进行了比较。我们的结果表明，这三种技术能够捕捉到两个研究流域的 DOM 动态。单独来看，所有三种方法都能够检测到流域 DOM 的主要来源，但方式更为有限。由于本研究中使用的便携式荧光计带宽较窄，因此对蛋白质类物质的 FDOM 测量几乎无法检测到。实际上，要求更高的 EEM-PARAFAC 不仅能够区分 DOM 的潜在来源，还能够提供不同有机成分的相对浓度估计。最后，与 FDOM 类似，但程度较轻，DOC 测量也显示出一些限制，其中蛋白质类物质构成了 DOM 组成的大部分。
