Natural Hydrogeochemical Background Levels in the Carste Lagoa Santa Protection Unit, Minas Gerais, Brazil

Aragão, Frederico; Velásquez, Leila Nunes Menegasse; Galvão, Paulo; Vieira, Luisa Costa Martins

doi:10.1016/j.jsames.2020.102985

Cited by 3 publications

(2 citation statements)

References 18 publications

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“…Among these, the alteration of granites and metamorphic rocks whose dissolution of potassium feldspars (orthoses) and plagioclases would be the origin of major cations (K + and Na + , Ca 2+ and Mg 2+ ) [36,69,77]. The alteration of schists, specifically the oxidation of sulfide ores (pyrite) contained in the gold-bearing veins to which fluorine is generally associated, is at the origin of SO 4 2− and F − [78]. The strong correlation between TSS and Hg in the low-water period could reflect the importance of the mercury adsorption phenomenon on the surface of very fine TSS, which present larger specific surfaces.…”

Section: Correlation Testsmentioning

confidence: 99%

Hydrogeochemistry and Mercury Contamination of Surface Water in the Lom Gold Basin (East Cameroon): Water Quality Index, Multivariate Statistical Analysis and Spatial Interpolation

Bella Atangana,

Ndam Ngoupayou,

Deliege

2023

Water

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Artisanal and small-scale gold mining activities have an impact on natural resources and human health. This study addresses the assessment of surface water quality in the Lom gold basin. A combined approach of water quality index calculation, multivariate statistical analysis and spatial interpolation was used. Sampling was performed at 15 stations during low- and high-water periods in 2021 for classical physicochemical parameters and total mercury measurements. The results show that the physicochemical parameters were below drinking water standards for both periods, except for pH, total suspended solids and total mercury. These waters show a large cation deficit as well as an anion deficit. The water chemistry is controlled by precipitations and silicate dissolutions in rock that convert the water into the Ca-HCO3 and Ca-Mg-HCO3 types. The level of mercury contamination varied from acceptable to high due to high flow rates during high water that cause a dilution effect for the mercury concentration upstream and its accumulation downstream. The water quality varied from excellent to very poor with better quality during the high-water period. The Lom watershed is locally affected by physical and chemical pollution due to the abundance of suspended solids and mercury resulting from the different gold mining activities.

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Section: Correlation Testsmentioning

confidence: 99%

Hydrogeochemistry and Mercury Contamination of Surface Water in the Lom Gold Basin (East Cameroon): Water Quality Index, Multivariate Statistical Analysis and Spatial Interpolation

Bella Atangana,

Ndam Ngoupayou,

Deliege

2023

Water

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“…The PAN San Francisco Caves Project, by Velásquez et al (2018), also resulted in many studies on this area, including the research of Ribeiro et al (2016), Vieira (2015), Lima et al (2016), Andrade and Amorim (2018), Magalhães and Silva (2018), Vieira (2018), Amaral (2018), Aragão (2019), Ribeiro (2020), De Paula (2019), De Souza (2020), Silva (2022) and Dantas (2023).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of recharge estimation methods applied to fissure and karst aquifers of the Lagoa Santa Karst Environmental Protection Area, Brazil

Teixeira,

de Paula,

Velasquez

et al. 2023

Hydrological Processes

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The Lagoa Santa Karst Environmental Protection Area is known worldwide as the place where the oldest human fossil in the Americas was found. Beyond its archaeological richness is speleological, faunistic and floristic richness across this remarkable karstic landscape. It is also a region with important aquifers for public and private water supply. Located in the state of Minas Gerais, Brazil, despite its environmental relevance, the area is characterized by increased anthropic environmental impacts. Regarding the relationship between surface water and groundwater, in order to investigate the annual input of water into the aquifers, this study aimed to estimate the annual recharge rate in the hydrological years 2017 to 2021 using three methods: the recession curve displacement method of Rorabaugh (International Association of Scientific Hydrology, 1964, 63:432–441), the recursive digital filter method by Lyne and Hollick (Institute of Engineers Australia National Conference, 1979, pp. 89–93), and the method based on water‐table fluctuation in tubular wells proposed by Healy and Cook (Hydrogeology Journal, 2002, 10(1):91–109). The average percentage of rainfall that is recharged into the aquifer, considering the overall period studied from 2017 to 2021, found with the three methods was 13%, 9% and 9%, respectively, which indicates that recharge rates within the study area are low and that higher values are observed within karst basins in comparison with basins located in pelitic zones. Overall, the methods yielded coherent values among each other and were compared with previous studies in the area. In relation to the automatized recursive digital filter method, the automatized recession curve displacement method was more adherent because it considers daily streamflow measurements. The WTF method was handy for the local recharge rate analysis and enabled an evaluation of recharge rates in each aquifer unit. Despite the similarity of the values obtained in the methods, they are likely underestimated due to the high pumping rates of groundwater. Furthermore, it is recommended to deepen the correlation between lithotype, karst geomorphology, and its dissolution processes to improve the understanding of recharge processes.

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Validation of the intrinsic vulnerability to pollution of fractured siliciclastic aquifers using natural background levels

Casadiegos-Agudelo,

Cetina-Tarazona,

Dominguez-Rivera

et al. 2024

Groundwater for Sustainable Development

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Natural Hydrogeochemical Background Levels in the Carste Lagoa Santa Protection Unit, Minas Gerais, Brazil

Cited by 3 publications

References 18 publications

Hydrogeochemistry and Mercury Contamination of Surface Water in the Lom Gold Basin (East Cameroon): Water Quality Index, Multivariate Statistical Analysis and Spatial Interpolation

Hydrogeochemistry and Mercury Contamination of Surface Water in the Lom Gold Basin (East Cameroon): Water Quality Index, Multivariate Statistical Analysis and Spatial Interpolation

Evaluation of recharge estimation methods applied to fissure and karst aquifers of the Lagoa Santa Karst Environmental Protection Area, Brazil

Validation of the intrinsic vulnerability to pollution of fractured siliciclastic aquifers using natural background levels

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