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This study aims to contribute to understanding the processes influencing the spatial distributions of trace metal elements in surface sediments of Brenne’s ponds (France) and assess potential pollution levels in the area. It was motivated by the lack of knowledge regarding the hydrogeochemical dynamics of limnic entities, which are ponds. To achieve this, 25 sediment samples were collected from Pond Thomas, considered as a ‘sentinel pond’, and underwent analysis for grain size, total organic carbon (TOC) concentrations, and trace metal elements (TMEs) (specifically Cu, Ni, Pb, As, Zn, Cr, and Cd). The results revealed that trace metal elements are primarily concentrated in two areas: the northwest section and the upstream region in the southern part of the pond. Applying various pollution indicators such as the enrichment factor (EF), geo-accumulation index (Igeo), and potential ecological risk index (RI), it was found that Pb and As are the most enriched elements, with respective EFs of 3.5 and 4.9. Their average concentrations exceed geochemical background values by 4 and 5.68 times in certain samples. The sediments in the southern part of the pond showed moderate contamination levels for As and Pb, with moderate to severe pollution (2 < Igeo < 3), reaching a maximum Igeo of 2.26 for As. Although the RI values across the pond are relatively low, Cd and As still pose moderate potential ecological risks. Additionally, principal component analysis and Pearson correlation analysis indicated two sources of TMEs in the area: Zn, As, Ni, Cd, Pb, and Cr are primarily from natural sources, while Cu appears to have a local anthropogenic origin. [ABSTRACT FROM AUTHOR]

In arid regions with increasing water needs due to growing populations and agriculture, heightened by climate change, groundwater arises as a crucial asset. This research evaluated climate change influence on groundwater potential zones (GPZs) during 2000 and 2014, within the Mostaganem plateau's alluvial aquifer in Algeria, using a methodology that integrates analytical hierarchy process (AHP), remote sensing (RS) and geographic information system (GIS). Forecasts for 2030 and 2050 were conducted using the QGIS MOLUSCE plugin. Findings reveal a (30.29%) decrease in zones of moderate potential, the vanishing of high potential sectors, alongside a (7.53%) and a (22.1%) rise in fair potential and low potential, respectively, from 2000 to 2014. Between 2014 and 2030, fair and moderate potential decrease by 6.62% and 0.48%, while low potential zones see a 7.47% increase. These shifts are linked to changes in rainfall distribution, and land use land cover (LULC), notably intensive agriculture of herbaceous crops. Slight changes are anticipated between 2030 and 2050, possibly due to the onset of a resilience equilibrium from 2030 onwards. These findings are crucial as a preliminary investigation, highlighting the necessity of optimal groundwater management. [ABSTRACT FROM AUTHOR]

The interactions between the normalised difference vegetation index (NDVI), the normalised difference built-up index (NDBI), and land surface temperature (LST) are complex. The assessment of land use/land cover (LULC) changes in the North-western region of Algeria between 1995 and 2021 confirms the direct influence of these factors on surface thermal processes. The use of new information technologies, particularly remote sensing coupled with GIS, favourably contributes to the processing of a large volume of data and to the use of specific methods aimed at confirming and/or disproving the hypotheses put forward. The application of LULC classification methods clearly highlights the magnitude of transformations, predominantly in favour of intensified urbanisation over the past two decades. Indeed, agricultural lands have experienced a reduction of 17.45%, while urbanised areas have nearly doubled. This phenomenon can, in part, be attributed to the mass migration of populations from inland areas to the coast, not only due to climate change: secondary for political problems between 1990 and 2001. Similarly, barren lands have increased by 10.45%. These changes have real implications for ecosystems (mainly loss of biodiversity) and the climate (pollution, GHG emissions, and rising ambient temperatures). The estimation of average LST from multiple satellite scenes reveals an increasing trend, rising from 36.6 °C in 1995 to 40.35 °C in 2021. The direct relationship between LST and NDVI and between LST and NDBI confirms the close association between land use change and increasing surface temperatures. The Pearson coefficient between LST and NDVI showed a negative correlation, ranging between -0.52 and -0.47, while it was positively correlated between LST and NDBI, with values around 0.66. The emergence of hotspots in the region, confirmed by the results of analysis employing the Getis-Ord G* method, is marked by clearly increasing spatial envelopes. This phenomenon is associated with a distinct reduction in vegetation cover density, coupled with an increased vulnerability to drought conditions. These initial results argue in favour of preserving green and blue networks and, more largely, ecosystems. [ABSTRACT FROM AUTHOR]