Search

Understanding the current water quality dynamics is necessary to ensure that ecological and sociocultural services are provided to the population and the natural environment. Water quality monitoring of lakes is usually performed with in situ measurements; however, these are costly, time consuming, laborious, and can have limited spatial coverage. Nowadays, remote sensing offers an alternative source of data to be used in water quality monitoring; by applying appropriate algorithms to satellite imagery, it is possible to retrieve water quality parameters. The use of global remote sensing water quality products increased in the last decade, and there are a multitude of products available from various databases. However, in Latin America, studies on the inter-comparison of the applicability of these products for water quality monitoring is rather scarce. Therefore, in this study, global remote sensing products estimating various water quality parameters were explored on Lake Titicaca and compared with each other and sources of data. Two products, the Copernicus Global Land Service (CGLS) and the European Space Agency Lakes Climate Change Initiative (ESA-CCI), were evaluated through a comparison with in situ measurements and with each other for analysis of the spatiotemporal variability of lake surface water temperature (LSWT), turbidity, and chlorophyll-a. The results of this study showed that the two products had limited accuracy when compared to in situ data; however, remarkable performance was observed in terms of exhibiting spatiotemporal variability of the WQ parameters. The ESA-CCI LSWT product performed better than the CGLS product in estimating LSWT, while the two products were on par with each other in terms of demonstrating the spatiotemporal patterns of the WQ parameters. Overall, these two global remote sensing water quality products can be used to monitor Lake Titicaca, currently with limited accuracy, but they can be improved with precise pixel identification, accurate optical water type definition, and better algorithms for atmospheric correction and retrieval. This highlights the need for the improvement of global WQ products to fit local conditions and make the products more useful for decision-making at the appropriate scale. [ABSTRACT FROM AUTHOR]

Human health and sustainable socio-economic growth are closely linked to water quality. Due to increasingly intense human activity, pollutants, and in particular trace elements, are entering the aquatic system and harming humans. The main objective of this study is to analyse and compare the impact of the trace elements on the water quality of natural springs. The concentrations of ten trace elements in 12 spring water samples collected in 2022 were analyzed using ICP-MS to determine the spatial variability of natural water quality in the Ouislane watershed. Nine major trace elements (boron, cobalt, chromium, copper, manganese, nickel, lead, zinc, and vanadium) were measured using the inductively coupled plasma mass spectrometry (ICP-MS) technique. The average values of these elements followed the descending trend: B > Ni > Cr > Co > Zn > Mn > V > Cu > Pb in spring water samples. Some trace elements measured in certain water samples exceed the upper limits set by Moroccan drinking water quality standards (NM) and the World Health Organization (WHO). From the principal components analysis (PCA), 83% of the variation is explained by the first three main components. B, Co, Cr and Ni have a strongly impact on water quality explain by their strong correlation with CP1 (R2 > 0.70). The calculated water quality index (WQI) values ranged from 61.18 to 95.11, with an average of 78.47. Approximately 17% of the water samples were categorized as excellent quality water (WQI < 50), with the remaining 83% classified as good quality water (50 < WQI < 100). According to the WQI index, all the natural spring waters investigated are deemed suitable for human consumption.

Africa depends on its water resources for hydroelectricity, inland fisheries and water supply for domestic, industrial and agricultural operations. Anthropogenic climate change (CC) has changed the state of these water resources. Land use and land cover have also undergone significant changes due to the need to provide resources to a growing population. Yet, the impact of the land-use and land cover change (LULCC) in addition to CC on the water resources of Africa is underexplored. Here we investigate how precipitation, evapotranspiration (ET) and river flow respond to both CC and LULCC scenarios across the entire African continent. We set up a Soil and Water Assessment Tool (SWAT +) model for Africa and calibrated it using the hydrological mass balance calibration (HMBC) methodology detailed in Chawanda et al. (2020a). The model was subsequently driven by an ensemble of bias-adjusted global climate models to simulate the hydrological cycle under a range of CC and LULCC scenarios. The results indicate that the Zambezi and the Congo River basins are likely to experience reduced river flows under CC with an up to 7 % decrease, while the Limpopo River will likely have higher river flows. The Niger River basin is likely to experience the largest decrease in river flows in all of Africa due to CC. The Congo River basin has the largest difference in river flows between scenarios with (over 18 % increase) and without LULCC (over 20 % decrease). The projected changes have implications for the agriculture and energy sectors and hence the livelihood of people on the continent. Our results highlight the need to adopt policies to halt global greenhouse gas emissions and to combat the current trend of deforestation to avoid the high combined impact of CC and LULCC on water resources in Africa. [ABSTRACT FROM AUTHOR]