Central Department of Environmental Science, Institute of Science and Technology, Tribhuvan University, Nepal.
Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
J Environ Manage. 2021 Jul 1;289:112522. doi: 10.1016/j.jenvman.2021.112522. Epub 2021 Apr 10.
COVID-19 pandemic has caused profound impacts on human life and the environment including freshwater ecosystems globally. Despite the various impacts, the pandemic has improved the quality of the environment and thereby creating an opportunity to restore the degraded ecosystems. This study presents the imprints of COVID-19 lockdown on the surface water quality and chemical characteristics of the urban-based Bagmati River Basin (BRB), Nepal. A total of 50 water samples were collected from 25 sites of BRB during the monsoon season, in 2019 and 2020. The water temperature, pH, electrical conductivity, total dissolved solids, dissolved oxygen (DO), and turbidity were measured in-situ, while the major ions, total hardness, biological oxygen demand (BOD), and chemical oxygen demand (COD) were analyzed in the laboratory. The results revealed neutral to mildly alkaline waters with relatively moderate mineralization and dissolved chemical constituents in the BRB. The average ionic abundance followed the order of Ca > Na > Mg > K > NH for cations and HCO> Cl > SO > NO > PO for anions. Comparing to the pre-lockdown, the level of DO was increased by 1.5 times, whereas the BOD and COD were decreased by 1.5 and 1.9 times, respectively during the post-lockdown indicating the improvement of the quality water which was also supported by the results of multivariate statistical analyses. This study confirms that the remarkable recovery of degraded aquatic ecosystems is possible with limiting anthropic activities.
新冠疫情大流行对人类生活和全球淡水生态系统等环境造成了深远影响。尽管疫情带来了各种影响，但它也改善了环境质量，为恢复退化的生态系统创造了机会。本研究展示了新冠疫情封锁对尼泊尔城市巴格马蒂河流域（BRB）地表水质量和化学特征的影响。在 2019 年和 2020 年季风季节，从 BRB 的 25 个地点共采集了 50 个水样。现场测量了水温、pH 值、电导率、总溶解固体、溶解氧（DO）和浊度，实验室分析了主要离子、总硬度、生物需氧量（BOD）和化学需氧量（COD）。结果表明，BRB 的水呈中性至微碱性，矿化度和溶解化学成分适中。平均离子丰度顺序为阳离子 Ca>Na>Mg>K>NH，阴离子 HCO>Cl>SO>NO>PO。与封锁前相比，封锁后 DO 增加了 1.5 倍，BOD 和 COD 分别降低了 1.5 和 1.9 倍，这表明水质得到了改善，多元统计分析的结果也支持了这一结果。本研究证实，限制人为活动可以实现退化水生生态系统的显著恢复。
