Search

The presence of microplastics in different environmental matrices has raised many concerns about potential effects of microplastics on humans and freshwater ecosystems. In Pakistan, rivers potentially receive microplastics from anthropogenic activities in their catchments. However, research studies regarding microplastics' presence, distribution, and risks are scarce in Pakistan. To bridge the gap, the present study was conducted to evaluate microplastic pollution in the Chenab River. Surface water samples were collected from selected sites on the Chenab River using a manta trawl in the low‐flow season during postmonsoon (October) 2019 and 2020 and in the high‐flow season during monsoon (July) 2020 and 2021. Samples were digested, followed by density separation and filtration. Identification and polymer characterization of microplastics were completed using stereomicroscopy and attenuated total reflection Fourier transform infrared spectroscopy, respectively. Microplastics were found in all samples with significant spatiotemporal variation in microplastic concentration, with an average of 45.98 ± 10.45 microplastics/m3 in the low‐flow season and 34.66 ± 16.15 microplastics/m3 in the high‐flow season. Among microplastic shapes, fibers were the most dominant shape, whereas polyethylene terephthalate (38.2%) and polypropylene (19%) were the most abundant polymers. Polymer risk index analysis and pollution load index demonstrated that most of the sites ranked as safe. The potential ecological risks from single polymers and combined polymers showed minor risks posed by microplastics. The present study is the first step to focus on microplastic pollution in the Chenab River; it will help river managers to mitigate the microplastic pollution without compromising the ecological integrity of the river. Environ Toxicol Chem 2023;42:727–739. © 2023 SETAC [ABSTRACT FROM AUTHOR]

A glacial lake outburst flood (GLOF) is a phenomenon that is widely known by researchers because such an event can wreak havoc on the natural environment as well as on manmade infrastructure. Therefore, a GLOF risk assessment is necessary, especially within river basins with hydropower plants, and may lead to a tremendous amount of socioeconomic loss if not done. However, due to the subjective and objective limitations of the available GLOF risk assessment methods, we have proposed a new and easily applied method with a wider application and without the need for adaptation changes in accordance with the subject area, which also allows for the repeated use of this model. In this study, we focused our efforts on the Upper Arun Hydroelectric Project (UAHEP) in the Arun River Basin, and we (1) identified 49 glacial lakes with areas greater than 0.1 km2; (2) geographically represented and analyzed these 49 glacial lakes for the period of 1990–2018; (3) analyzed the correlation between the temperature and precipitation trends and the occurrence of recorded GLOF events in the region; (4) proposed a new method based on the documented affected lengths and volumes derived from historical GLOF events to identify 4 potentially critical lakes; and (5) evaluated the discharge profiles using widely used empirical methods and further discussed the physical properties, triggering factors, and outburst probability of the critical lakes. To achieve these objectives, a series of intensive and integrated desk studies, data collections, and GLOF simulations and analyses were performed. [ABSTRACT FROM AUTHOR]