Glyphosate (GPS) is an herbicide currently used on olive crops in Spain, and can be transported to the nearby reservoirs currently used for human consumption. The purpose of this work was to study ...the behaviour and environmental fate of GPS in water and sediments of the Vibora Reservoir, its tributary river, and the surrounding agricultural soils to assess the risk of water pollution of this reservoir. The adsorption of GPS by different matrices was as follows: heading of the reservoir sediment (Cabecera)>tail sediment (Cola)>soils>Vibora sediment. The highest amount of oxides (especially Fe oxides) was observed in sediments from Cabecera and Cola whereas the lowest values were recorded on Vibora sediment. Results indicate that the highest GPS adsorption is due to the amorphous oxides and the edge sites of the clay minerals. Glyphosate adsorption increased with decreasing pH from 8 to 7. The desorption percentage of GPS from the four soils studied ranged only from 0.40 to 1.22%. Desorption was almost irreversible for Cabecera and Cola sediments, with values between 0 and 1.1%. Conversely, Vibora sediment presented about 20% desorption, probably due to its coarse texture and lower levels of amorphous oxides. Hockey-stick first-order kinetics was the best descriptor for water glyphosate dissipation at the Cabecera and Cola locations, and simple first-order kinetic for the water from the tributary Vibora River. The half-lives (DT50) were between 6.3 and 11.0days. The rapid degradation of GPS in surface waters and its practically irreversible sorption on these soils and sediments implies that GPS use in similar agricultural areas is of very low environmental risk. This manuscript also outlines the importance of the presence of photo-sensitizers in waters in the degradation routes of GPS in reservoirs.
•High GPS adsorption to surrounding soils due to amorphous oxides and clay minerals•Extremely high adsorption capacity of reservoir sediments for GPS•GPS desorption from soils and sediments almost irreversible•High levels of amorphous oxides act as photosensitizers for GPS water dissipation.•High GPS sorption on sediments and dissipation in water reduce its environmental impact.
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Uranium (U) geochemistry and its isotopic compositions of reservoir sediments in U mine area were poorly understood. Herein, U and Th isotopic compositions were employed to investigate source ...apportionment and geochemical behavior of U in 41 reservoir sediments from a U mining area, Guangdong, China. The remarkably high contents of both total U (207.3–1117.7 mg/kg) and acid-leachable U (90.3–638.5 mg/kg) in the sediments exhibit a severe U contamination and mobilization-release risk. The U/Th activity ratios (ARs) indicate that all sediments have been contaminated apparently by U as a result of discharge of U containing wastewater, especially uranium mill tailings (UMT) leachate, while the variations of U/Th ARs are dominated by U geochemical behaviors (mainly redox process and adsorption). The U isotopic compositions (δ238U) showed a large variance through the sediment profile, varying from − 0.62 to − 0.04‰. The relation between δ238U and acid-leachable U fraction demonstrates that the U isotopic fractionation in sediments can be controlled by bedrock weathering (natural activity), UMT leachate (anthropogenic activity) and subsequent biogeochemical processes. The findings suggest that U-Th isotopes are a powerful tool to better understand U geochemical processes and enrichment mechanism in sediments that were affected by combined sources and driving forces.
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•Extremely U contamination and re-migration risk were observed in reservoir sediments.•U sources and geochemical behaviors were studied using U-Th isotopes.•U enrichment mechanisms (reduction/adsorption) were distinguished by isotopic perspective.•U6+ to U4+ is the dominant mechanism leading to the U enrichment and isotopic fractionation.
Two dated sediment cores from the Miyun Reservoir of Beijing in China were analyzed to reconstruct the pollution history of heavy metals including cadmium (Cd), chromium (Cr), iron (Fe), nickel (Ni), ...and zinc (Zn) as well as phosphorus (P). Enrichment factor (EF) and geoaccumulation index (Igeo) were applied to assess the enrichment status of heavy metals. Average EF and Igeo values indicated that the studied heavy metals in the sediments mainly originated from non-point source pollution and soil-water erosion, showing low ecological risks. In addition, correlation analysis and principal component analysis (PCA) identified that Cd, Zn, and P were mainly from agricultural diffusion pollution caused by utilization of the phosphate fertilizer; Zn, Ni, and Cr originated from soil erosion. PCA analysis was further conducted to investigate the relationships among meteorological factors, algae-dominant total organic carbon (TOC), and heavy metals. Results showed that algae-dominant TOC had strong positive correlation with temperature, which can be explained by that increased temperature accelerated the growth of algae. Meanwhile the opposite loadings between algae-dominant TOC and heavy metal suggested that primary production played an important role in migration and transformation of metals. Moreover, stepwise multiple regression models showed that Fe was sensitive to temperature, which accounted for approximately 39.0% and 40.1% of the variations in Fe of two sediment cores, respectively. Fe showed significant decreasing trends during the past 50years. Reductive environment of water-sediment interface caused by increasing temperature probably contributed to the restoration of ferric iron, resulting in the release of soluble Fe to overlying waters. Future climate change with elevated temperature and extreme weather events will aggravate the ecological risk of heavy metals in water environment due to the enhanced leaching effect and non-point source pollution as well as the release of heavy metals from sediments to water environment.
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•Enrichment factors showed most of heavy metals were from anthropogenic activities.•Cd, Zn, and P were mainly from the agricultural non-point source pollution.•Algae-dominant TOC was negatively correlated with heavy metals in the sediments.•Future climate change may have adverse impact on heavy metals in the aquatic environment.
Water reservoir sediments represent a distinct habitat that harbors diverse microbial resources crucial for nitrogen cycling processes. The discovery of resuscitation promoting factor (Rpf) has been ...recognized as a crucial development in understanding the potential of microbial populations. However, our understanding of the relationship between microorganisms containing rpf -like genes and nitrogen-cycling functional populations remains limited. The present study explored the distribution patterns of rpf -like genes and nitrogen-cycling genes in various water reservoir sediments, along with their correlation with environmental factors. Additionally, the co-occurrence of rpf -like genes with genes associated with the nitrogen cycle and viable but non-culturable (VBNC) formation was investigated. The findings indicated the ubiquitous occurrence of Rpf-like domains and their related genes in the examined reservoir sediments. Notably, rpf -like genes were predominantly associated with Bradyrhizobium , Nitrospira , and Anaeromyxobacter , with pH emerging as the primary influencing factor for their distribution. Genera such as Nitrospira , Bradyrhizobium , Anaeromyxobacter , and Dechloromonas harbor the majority of nitrogen-cycling functional genes, particularly denitrification genes. The distribution of nitrogen-cycling microbial communities in the reservoir sediments was mainly influenced by pH and NH 4 + . Notably, correlation network analysis revealed close connections between microorganisms containing rpf -like genes and nitrogen-cycling functional populations, as well as VBNC bacteria. These findings offer new insights into the prevalence of rpf -like genes in the water reservoir sediments and their correlation with nitrogen-cycling microbial communities, enhancing our understanding of the significant potential of microbial nitrogen cycling.
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•Magnetic parameters as proxies for element pollution in water reservoirs.•Element contamination is mainly associated with historical mining activities.•Iron oxides and iron sulfides ...are detected and characterized in water reservoir sediments.•Multivariate analysis for magnetic and enrichment variables shows differences between reservoir and basin sediments.
We assess the element pollution level of water reservoir sediments using environmental magnetism techniques as a novel approach. Although “La Purísima” Water Reservoir is an important source for multiple activities (e.g. recreational, fishing and agricultural) in Guanajuato state, it has been receiving for the last centuries a high load of pollutants by mining extraction, urbanization and land-use change from the Guanajuato Hydrological Basin. The analyses of environmental magnetism, geochemistry, X-ray energy dispersive spectroscopy, scanning electron microscopy and multivariate methods were applied to study sediments from the reservoir and basin. Accordingly, they indicate the presence of iron oxides (magnetite and hematite) and iron sulfides (pyrite and greigite), which evidences relevant differences in particle size and concentration within the water reservoir (median mass-specific magnetic susceptibility χ = 23.2 × 10−8 m3/kg), as well as with respect to the river basin sediments (median χ = 88.8 × 10−8 m3/kg). The highest enrichment factor EF values (median values of EF = 2–10 for As, Co, Ba, Cu, Cd, Ni and EF > 20 for S) are mainly associated with historical mining activities that have led to an enrichment of potentially toxic elements on these water reservoir sediments. We propose the use of concentration and grain size dependent magnetic parameters, i.e. χ, remanent magnetizations and anhysteretic ratios ARM/SIRM and χARM/χ, as proxies for Ba, Co, Cr, Ni, P and Pb pollution in these river and water reservoir sediments. Such parameters allow to evaluate this sedimentary environment, and similar ones, through useful and convenient proxies.
Pollutions of trace metals (TMs) in reservoirs are blooming due to TMs were trapped efficiently in reservoir sediments by dams. Despite the mobilization of TMs in sediments have been well-documented, ...the patterns of biogeochemical processes occurred in sediments remain poorly understanding. Herein, a deep reservoir was selected to investigate the patterns of TMs biogeochemical processes in sediments by using high-resolution ZrO-Chelex-AgI diffusive gradient in thin films technique (HR-ZCA DGT) and the laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). 2-dimension high-resolution (2D-HR) images showed significant differential spatial enrichment of TMs (V, Mn, Fe, Co, Zn and Sb) in sediments, indicating strong heterogeneity in sediments. Correlations of TMs within microniches (diameter < 1 mm) in horizontal were usually different even contrast with that in vertical profile, suggesting distinct biogeochemical process patterns occurred in vertical vs. in horizontal. Further analyses from 2D-HR images showed the distributions of TMs in microniches reflected their mobilization that was driven by microenvironmental conditions. In contrast, distributions in sediment vertical profile recorded the diagenesis in different deposition depth. The diagenesis in sediment vertical is continuously accumulated by the discrete, microniches mobilization of TMs in horizontal. Collectively, our findings evidenced that 2D-HR data is an update complement to 1-dimension data for better interpret the biogeochemical process patterns of TMs in sediments, that have implication for water management to metals pollution in reservoir ecosystems.
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•2D-HR distributions of TMs in sediments were determined by LA-ICP-MS.•Distributions within microniches in horizontal reflect mobilization of TMs.•Vertical distributions record the diagenesis of TMs in sedimentation.•2D-HR data broad the understanding to the biogeochemical processes of TMs.
The rising temperatures, increased evaporation, and altered precipitation patterns associated with global warming pose threats to aquatic ecosystems, especially the salinization of lake water and ...changes in the terrestrial carbon budget. We studied a series of samples of catchment soils, surface sediments, and sediment cores from 51 lakes and reservoirs covering an extensive climatic range in northeastern China. Measurements included salinity indices (electrical conductivity and pH) and other physicochemical parameters, including magnetic properties and color (chroma). The results indicate that the occurrence of salt minerals and the salinity of the lake sediments are dominated by the arid climatic conditions of the region. This enabled us to develop climatic transfer functions between salinity, precipitation and evaporation, with potential applications in paleoclimatic research. As carbonates are the dominant salts in most of the studied lakes and reservoirs, past salinity variations are likely reflected by changes in HCO3- and CO32- concentrations, which provides the opportunity to study the response of water-CO2-carbonate interactions to climate change. Our findings emphasize the important role of alkaline lakes in carbon burial and carbon neutralization, in the context of ongoing global warming.
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•Spatial and depth profiles of salinity in lake/reservoir sediments•A direct and rapid method for paleoclimate reconstruction•Carbon burial in saline and alkaline lakes under global warming
Chemical partitioning of heavy metals (Fe, Mn, Cu, Cr, Pb, Zn, Ni) were determined in surface sediments of three reservoirs at the Delta region of Cauvery River, India. The abundance of metals in ...sediments varied in the following descending order: Fe, Mn, Cr, Zn, Cu, Ni, and Pb. Higher concentrations of Zn, Pb, Fe, Mn and Cu in exchangeable and carbonate fraction indicated toxicity risk to the biota. Therefore, to understand the extent of bioaccumulation, six commercial fish species were collected from the same sites and analyzed for heavy metals distribution in different organs. Among the metals found in fish samples, iron was observed in the highest concentration, followed by Zn, Pb, Cr, Mn, Cu, and Ni. Concentrations of Pb, Cr and Zn in many fish samples exceeded the permissible limits of Food and Agriculture Organization. The concentrations of Pb (17.7–31.7%), Cr (6.2–15.1%), Cu (15.2-30.5%) and Zn (30–40%) associated with exchangeable and carbonate fractions had significant positive correlation with the respective metal concentrations in fish. Among the fish species, Catla catla and Etroplus suratensis showed the highest accumulation of metals suggesting risk for human consumption.
•Heavy metal partitioning in sediments was determined and it was related to bioaccumulation in fish.•Substantial proportion of Pb, Cu and Zn was observed in the exchangeable fraction of the sediments.•Pb, Cr and Zn level in most of the fish samples exceeded the permissible limits.•Positive correlation was observed between labile fraction of Cu and Pb in sediments and the corresponding concentrations in tissues.
Reservoirs can intercept upstream inputs and greatly alter their migration and transformation processes at a basin scale. Taking a typical reservoir basin in the Xiaoxing'an Mountains of Northeast ...China as an example, the organic phosphorus (Po) and organic matter (OM) compositions in the upstream soil, river and reservoir sediments were characterized by 31P NMR, stable carbon (δ13C) and nitrogen isotopes (δ15N), and the migration and transformation processes of Po from soil to reservoir sediments were explored. The compositional data indicated that both the OM and Po in the reservoir were mainly imported by C3 plants from the upper reaches. Higher monoester phosphorus (P) components in the upstream soils than in the reservoir sediments, which indicated the migration and degradation process of Po from the upstream soils to the river and then to the reservoir sediments. The degradation rate of monoester P was higher, approximately 30.6% and the phosphonate fraction had the lowest degradation rate, about 0.4%. Specifically, the degradation of monoester P including inositol P was higher than that of organic carbon. Thus, at the basin scale, more forest-derived organic carbon was likely intercepted by reservoirs and precipitated to sediments, while Po might degrade to a greater extent. Aggregative results showed that reservoirs may play an important role in the differentiated migration and transformation process of forest-derived OM and Po. And then, the highly degradable Po including inositol P poses a greater risk of eutrophication in the typical temperate forest reservoirs and their downstream, even the ocean, and is accompanied by possible algal blooms in the future. Information derived from this study provides a more scientific basis for the assessment of the ecological and environmental effects of reservoir and dam construction projects.
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•Organic matter (OM) and organic P (Po) are mainly from C3 plants in the basin.•Degradation rate of Po was greater than that of OM in a forest basin.•Approximately 30.6% of monoester P and 0.4% of phosphonate were degraded.•Reservoir building differentiated geochemical cycling of forest-derived OM and Po.•Reservoirs intercept a greater percentage of OM than Po from forest soils.
The inter-element relationships and the forms in which metals exist strongly influence their mobility and, in turn, have a signature on the environment and human health. Located in the northern ...Apennines within the Emilia-Romagna region, the Ridracoli artificial lake is one of Italy's most important reservoirs that provides drinking water for about one million people. This work characterized the reservoir sediments by ICP-MS after aqua regia digestion (ARD), comparing the limits by law to assess environmental compliance and XRF data from the same sample-set taken as total concentrations. The Degree of Extraction (DE) from pseudo-total concentrations of ARD analysis allows assessing elements mobility and the associated environmental risk. Principal Component Analysis (PCA) on the obtained data helped to investigate inter-element relationships better; for example, we observed carbonate-sourced sediments, many trace elements (e.g., Ni, Zn) linked to FeMn oxyhydroxides, the importance of the grain size in elements distribution, and the central role of the organic matter in element partitioning. In addition, a Sequential Extraction Procedure (SEP) was applied to the sediment samples to understand the partitioning of many analytes, including Potentially Harmful Elements (PHE) such as Fe, Mn, Cu, Cr, Ni, Pb, and Zn. The results indicated that the most easily mobilized forms were predominant in the area near the dam, in correspondence to sediments affected by the formation of a seasonal anoxic layer.
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•Water reservoirs require environmental assessment of bottom sediments quality.•Mostly carbonatic sediments with trace elements linked to FeMn oxyhydroxides.•PCA explored interelement and organic matter relationships, and grain-size effects.•SEP assessed elements partitioning and mobility as a function of seasonal condition.•Potentilly Harmful Elements (PHEs) concentration is likely low in the sediment.
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