Natural and anthropogenic impacts on the geochemical composition and metal speciation of fine sediment in a glacier-fed Canadian river basin

Author(s):  
M. Stone ◽  
A. L. Collins ◽  
J. P. Laceby
1993 ◽  
Vol 28 (1) ◽  
pp. 83-110 ◽  
Author(s):  
Richard E. Farrell ◽  
Jae E. Yang ◽  
P. Ming Huang ◽  
Wen K. Liaw

Abstract Porewater samples from the upper Qu’Appelle River basin in Saskatchewan, Canada, were analyzed to obtain metal, inorganic ligand and amino add profiles. These data were used to compute the aqueous speciation of the metals in each porewater using the computer program GEOCHEM-PC. The porewaters were classified as slightly to moderately saline. Metal concentrations reflected both the geology of the drainage basin and the impact of anthropogenic activities. Whereas K and Na were present almost entirely as the free aquo ions, carbonate equilibria dominated the speciation of Ca. Mg and Mn (the predominant metal ligand species were of the type MCO3 (s). MCO30. and MHCO3+). Trace metal concentrations were generally within the ranges reported for non-polluted freshwater systems. Whereas the speciation of the trace metals Cr(III) and Co(II) was dominated by carbonate equilibria, Hg(II)-, Zn(II)- and Fe(II)-speciation was dominated by hydroxy-metal complexes of the type M(OH)+ and M(OH)2°. The speciation of Fe(III) was dominated by Fe(OH)3 (s). In porewaters with high chloride concentrations (> 2 mM), however, significant amounts of Hg(II) were bound as HgCl20 and HgClOH0. The aqueous speciation of Al was dominated by Al(OH)4− and Al2Si2O4(OH)6 (s). Total concentrations of dissolved free amino acids varied from 15.21 to 25.17 umole L−1. The most important metal scavenging amino acids were histidine (due to high stability constants for the metal-histidine complexes) and tryptophan (due to its relatively high concentration in the porewaters. i.e., 5.96 to 7.73 umole L−1). Secondary concentrations of various trace metal-amino add complexes were computed for all the porewaters, but metal-amino acid complexes dominated the speciation of Cu(II) in all the porewaters and Ni(II) in two of the porewaters.


2005 ◽  
Vol 62 (12) ◽  
pp. 2740-2751 ◽  
Author(s):  
Jeff J Opperman ◽  
Kathleen A Lohse ◽  
Colin Brooks ◽  
N Maggi Kelly ◽  
Adina M Merenlender

Relationships between land use or land cover and embeddedness, a measure of fine sediment in spawning gravels, were examined at multiple scales across 54 streams in the Russian River Basin, California. The results suggest that coarse-scale measures of watershed land use can explain a large proportion of the variability in embeddedness and that the explanatory power of this relationship increases with watershed size. Agricultural and urban land uses and road density were positively associated with embeddedness, while the opposite was true for forest cover. The ability of land use and land cover to predict embeddedness varied among five zones of influence, with the greatest explanatory power occurring at the entire-watershed scale. Land use within a more restricted riparian corridor generally did not relate to embeddedness, suggesting that reach-scale riparian protection or restoration will have little influence on levels of fine sediment. The explanatory power of these models was greater when conducted among a subset of the largest watersheds (maximum r2 = 0.73) than among the smallest watersheds (maximum r2 = 0.46).


2010 ◽  
Vol 10 (2) ◽  
pp. 253-260 ◽  
Author(s):  
Karina Ocampo Righi-Cavallaro ◽  
Marcia Regina Spies ◽  
Ana Emilia Siegloch

The knowledge on the Ephemeroptera, Plecoptera and Trichoptera (EPT) assemblages in running waters of Mato Grosso do Sul State is still deficient. As a contribution to improve this situation, this study presents an inventory of immature EPT assemblages in Miranda River basin. The samples were collected between January and September 2006 from 4th to 7th orders river reaches. A total of 3069 larvae were collected, belonging to 49 genera and 17 families. The caddisflies presented the greatest abundance while the mayflies presented the greatest richness. Of the larvae collected, 22 genera of Ephemeroptera and 20 of Trichoptera are new occurrences for the State. The high genera richness observed in this study, with sites subjected to moderate to high human impacts, as well as the high genera richness indicated by non-parametric estimators and by the genera accumulation curve, indicate that the EPT richness of Miranda River basin is high. This result seems to be related to the environmental heterogeneity of the basin catchment (Cerrado and Pantanal biomes; carbonate, sedimentary and basaltic rocks). Additionally, these results should incentive future ecological and environmental integrity studies in the region, which are urgent in a landscape under fast anthropogenic impacts.


2020 ◽  
Vol 12 (20) ◽  
pp. 3329
Author(s):  
Sajad Khoshnoodmotlagh ◽  
Jochem Verrelst ◽  
Alireza Daneshi ◽  
Mohsen Mirzaei ◽  
Hossein Azadi ◽  
...  

Changes in land cover (LC) can alter the basin hydrology by affecting the evaporation, infiltration, and surface and subsurface flow processes, and ultimately affect river water quantity and quality. This study aimed to monitor and predict the LC composition of a major, transboundary basin contributing to the Caspian Sea, the Aras River Basin (ARB). To this end, four LC maps of ARB corresponding to the years 1984, 2000, 2010, and 2017 were generated using Landsat satellite imagery from Armenia and the Nakhchivan Autonomous Republic. The LC gains and losses, net changes, exchanges, and the spatial trend of changes over 33 years (1984–2017) were investigated. The most important drivers of these changes and the most accurate LC transformation scenarios were identified, and a land change modeler (LCM) was applied to predict the LC change for the years 2027 and 2037. Validation results showed that LCM, with a Kappa index higher than 81%, is appropriate for predicting LC changes in the study area. The LC changes observed in the past indicate significant anthropogenic impacts on the basin, mainly by constructing new reservoir dams and expanding agriculture and urban areas, which are the major water-consuming sectors. Results show that over the past 33 years, agricultural areas have grown by more than 57% from 1984 to 2017 in the study area. Results also indicate that the given similar anthropogenic activities will keep on continuing in the ARB, and agricultural areas will increase by 2% from 2017 to 2027, and by another 1% from 2027 to 2037. Results of this study can support transboundary decision-making processes to analyze potential adverse impacts following past policies with neighboring countries that share the same water resources.


2021 ◽  
Author(s):  
Isabela Martins ◽  
Diego M. P. Castro ◽  
Diego R. Macedo ◽  
Robert M. Hughes ◽  
Marcos Callisto

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