This paper presents the results of spectral optical measurements of hydrochemical characteristics in the Angara/Yenisei river system (AYRS) extending from Lake Baikal to the estuary of the Yenisei River. For the first time, such large-scale observations were made as part of a joint American–Russian expedition in July and August of 1995, when concentrations of radionuclides, heavy metals, and oil hydrocarbons were assessed. The results of this study were obtained as part of the Russian hydrochemical expedition in July and August, 2019. For in situ measurements and sampling at 14 sampling sites, three optical spectral instruments and appropriate software were used, including big data processing algorithms and an AYRS simulation model. The results show that the water quality in AYRS has improved slightly due to the reasonably reduced anthropogenic industrial impact. Chemical concentrations in water have been found to vary along the Angara River depending on the location of the dams. The results of in situ measurements and modeling evaluations are given. To overcome the uncertainties in the data caused by the large monitoring area, it is recommended to use the combined AYRS simulation model and the universal 8-channel spectrophotometer installed on a fixed platform for continuous monitoring.

中文翻译：

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用于诊断水介质质量的光学光谱工具：以西伯利亚地区的安加拉河/耶尼西河系统为例

本文介绍了从贝加尔湖到叶尼塞河河口的安加拉/耶尼塞河系统（AYRS）水化学特征的光谱光学测量结果。作为1995年7月和8月美俄联合考察的一部分，首次进行了这种大规模观测，当时评估了放射性核素，重金属和石油碳氢化合物的浓度。这项研究的结果是2019年7月和8月在俄罗斯进行的水化学考察的一部分。在14个采样点进行现场测量和采样时，使用了三种光谱仪器和适当的软件，包括大数据处理算法和AYRS模拟模型。结果表明，由于合理减少了人为的工业影响，AYRS的水质略有改善。已发现安加拉河沿岸的水中化学物质浓度随水坝的位置而变化。给出了现场测量和建模评估的结果。为了克服由较大的监视区域引起的数据不确定性，建议使用组合的AYRS仿真模型和安装在固定平台上的通用8通道分光光度计进行连续监视。