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  • 1.
    Ormachea, Mauricio
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Blanco, E.
    Ramos, Oswaldo
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Garcia, M.
    IIQ, UMSA, La Paz, Bolivia.
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Arsenic occurrence in thermal springs of the Central Bolivian Altiplano2010In: Arsenic in the Environment—Proceedings / [ed] Jochen Bundschuh and Prosun Bhattacharya, 2010, p. 520-522Conference paper (Refereed)
  • 2.
    Ormachea Muñoz, Mauricio
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering. Instituto de Investigaciones Químicas-UMSA.
    Hydrogeochemistry of Naturally Occurring Arsenic and Other Trace Elements in the Central Bolivian Altiplano: Sources, mobility and drinking water quality2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The Bolivian Altiplano (BA) is a high plateau located in the western part of the country at an altitude of 3,600 to 3,900 meters above sea level and is bordered by the Eastern and Western Cordillera. Within the BA there is a large endorheic hydrologic system linking the Titicaca Lake in the north the Desaguadero River, lakes Uru-Uru and Poopó in the central part; and the Lacajahuira River and Coipasa and Uyuni salt pans in the south. Several mineralized areas, especially in the Eastern Cordillera, have been intensively exploited for centuries for the extraction of silver, gold, and tin from polymetallic sulfide ore deposits. Presently many urban centers are also contributing for an extensive contamination in localized areas; especially the Poopó Lake and some rivers are affected by high loads of wastewater and solid waste, in addition to the release of heavy metals and arsenic (As) due to acid mine drainage.

    The presence of As in the BA was known to be related to mining only, but recent studies revealed that As of geogenic origin also contributing to the elevated concentration of As in surface and groundwater. The Poopó Lake basin is characterized by a semiarid climate. Geologic formations predominantly are of volcanic origin and groundwater flow is sluggish in nature. These environmental settings have generated substantially elevated concen- trations of geogenic As and other trace elements in surface and groundwater. Both surface and groundwater used for drinking water have high concentrations of As that by far exceed the World Health Organization (WHO) guideline. The overall objective of the present study has been focused on the determination of the sources and principal mechanisms for mobilization of geogenic As into surface and groundwater of the Poopó Lake basin area. More specifically, this study has determined the spatial distribution and the extent of As contamination in surface and groundwater; chemical composition of surface and groundwater, rock and sediment; major geochemical mechanisms for As mobilization from solid phase to aqueous phases. This study also made an assessment of drinking water quality in rural areas within the Poopó Lake basin.

    Arsenic concentration exceeded the WHO guideline and national regulations for drinking water of 10 µg/L in 85% of the samples collected from the area around the Poopó Lake (n=27) and 90% of the samples from the southern part of the lake basin (n=42). Groundwater samples collected from drinking water wells had As concentrations up to 623 µg/L, while samples collected from piezometers had even higher up to 3,497 µg/L. Highest concentration in river water samples was observed 117 µg/L. Alkaline nature of water (median pH 8.3 for groundwater and 9.0 for surface water), predominance of Na-Cl-HCO3 water type and elevated Eh reflecting oxidized character has been revealed by As(V) as the major species in As speciation. Different rock types were analyzed for their As content and the highest concentration of 27 mg/kg was found in a coral limestone sample. In evaporate it was 13 mg and 11 mg As/kg was measured in calcareous sandstone. Elevated concentration of As was also observed in sediment cores collected from two drilling sites; 51 mg/kg in Condo K and 36 mg/kg in Quillacas. Physical and chemical weathering of volcanic rocks, limestone, carbonates and plagioclase minerals enhance the supply of Na+ and HCO3- into solution and as a consequence pH and alkalinity increase, which in turn, favor As desorption from solid mineral surfaces (especially Fe(III) oxyhydr- oxides) and therefore dissolved As in water is increased.

  • 3.
    Ormachea Muñoz, Mauricio
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering. Instituto de Investigaciones Quimicas-UMSA.
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Šráček, Ondra
    Ramos Ramos, Oswaldo Eduardo
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Quintanilla Aguirre, Jorge
    Bundschuh, Jochen
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Maity, Jyoti Prakash Rakash
    Arsenic and other trace elements in thermal springs and in cold waters from drinking water wells on the Bolivian Altiplano2015In: Journal of South American Earth Sciences, ISSN 0895-9811, E-ISSN 1873-0647, Vol. 60, p. 10-20Article in journal (Refereed)
    Abstract [en]

    Numerous hot springs and fumaroles occur along the Andes Mountains, in the Bolivian Altiplano, where people use thermal springs for recreational purposes as pools, baths and also for consumption as drinking water and irrigation once it is mixed with natural surface waters; most of these thermal springs emerge from earth surface and flow naturally into the rivers streams which drain further into the Poopo Lake. Physicochemical characteristics of the thermal water samples showed pH from 6.3 to 8.3 with an average of 7.0, redox potential from +106 to +204 mV with an average of +172 mV, temperatures from 40 to 75 °C with an average of 56 °C and high electrical conductivity ranging from 1.8 to 75 mS/cm and averaged 13 mS/cm. Predominant major ions are Naþ and Cl and the principal water types are 37.5% Na-Cl type and 37.5% Na-Cl-HCO3 type. Arsenic concentrations ranged from 7.8 to 65.3 μg/L and arsenic speciation indicate the predominance of As(III) species. Sediments collected from the outlets of thermal waters show high iron content, and ferric oxides and hydroxides are assumed to be principal mineral phases for arsenic attenuation by adsorption/co-precipitation processes. Arsenic concentrations in cold water samples from shallow aquifers are higher than those in thermal springs (range < 5.6-233.2 μg/L), it is likely that thermal water discharge is not the main source of high arsenic content in the shallow aquifer as they are very immature and may only have a small component corresponding to the deep geothermal reservoir. As people use both thermal waters and cold waters for consumption, there is a high risk for arsenic exposure in the area.

  • 4.
    Ormachea Muñoz, Mauricio
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Garcia Arostegui, Jose L.
    Garcia Moreno, Maria E.
    Kohfahl, Claus
    Quintanilla, Jorge
    Hornero Diaz, Jorge
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Geochemistry of naturally occurring arsenic in groundwater and surface-water in the southern part of the Poopó Lake basin, Bolivian Altiplano2016In: Groundwater for Sustainable Development, ISSN 2352-801X, Vol. 2-3, p. 104-116Article in journal (Refereed)
    Abstract [en]

    Groundwaters from shallow aquifers and surface water from rivers of the southern part of Poopó Lake basin within the Bolivian Altiplano have significant quality problems such as high salinity and high concentrations of arsenic (As). The extent of As contamination is observed in the studied groundwater over large parts of the study area. Surface-waters are generally alkaline (pH 8.2–8.7) and oxidizing with dissolved oxygen (DO) concentrations in a range of 2.5–6.6 mg/L The water chemistry is predominantly of Na–Cl–HCO3–type, with concentrations of dissolved As in the range of 8.6–117 µg/L with As(V) as the main aqueous species. The concentration of Li varies in the range of 1.1–4.4 mg/L, while other trace elements occur in low concentrations. Groundwaters have a very large range of chemical compositions and the spatial variability of As concentrations is considerable over distances of a few km; dissolved As in groundwater spans over 4 orders of magnitude (3–3497 µg/L), while concentrations of Li have a range of 0.05–31.6 mg/L. Among the investigated drinking-water wells, 90% exceed the WHO guideline value of 10 µg As/L. Electrical conductivity ranges between 295 and 20,900 µS/cm; high salinity is resulting from evaporation under ambient semi-arid climatic conditions. The pH values of the groundwaters are generally slightly alkaline (5.5–8.7) and universally oxidizing, under these conditions As(V) is the prevalent specie. Groundwater As correlates positively with pH, electrical conductivity, Cl, Na+, HCO3 , Ca2+ and SO4 2−. Weathering/dissolution of carbonates, evaporites, halite and plagioclase minerals incorporate Na+ and HCO3 in solution with consequent pH and alkalinity increase; these are favorable conditions for high mobility of As species. Stable isotopic signatures indicate recharge at the Altiplano with seasonal effects. All surface water and some groundwater samples are enriched due to evaporation, which probably increased concentration of dissolved As.

  • 5.
    Ormachea Muñoz, Mauricio
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering. Universidad Mayor de San Andrés, Bolivia .
    Huallpara, L.
    Blanco Coariti, E.
    García Aróstegui, J. L.
    Kohfahl, C.
    Hidalgo Estévez, M. C.
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Natural arsenic occurrence in drinking water and assessment of water quality in the southern part of the Poopó lake basin, Bolivian Altiplano2014In: One Century of the Discovery of Arsenicosis in Latin America (1914-2014): As 2014 - Proceedings of the 5th International Congress on Arsenic in the Environment, 2014, p. 154-156Conference paper (Refereed)
    Abstract [en]

    Drinking water quality and the presence of natural arsenic (As) were studied in a rural, less developed area of the southern part of the Poopó lake basin in the Central Bolivian Altiplano. People in this area use untreated surface- and ground-water directly as drinking water. Water is extracted from excavated wells and from few rivers occasionally present during the rainy season. Forty-one wells and seven different sites along four rivers were sampled as they are common sources for drinking water. The main characteristics of the sampled waters showed a slightly alkaline pH, high electrical conductivity and high salinity where the principal components were sodium, chloride and bicarbonate. Arsenic concentrations reached values up to 623 μg L -1 exceeding the current WHO guideline value (10 μg L -1) in all rivers and in ninety-five percent of the sampled wells. Heavy metals and other trace elements showed relatively low concentrations.

  • 6.
    Ormachea Muñoz, Mauricio
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Wern, Hannes
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Johnsson, Fredrick
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Sracek, O.
    Thunvik, Roger
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Quintanilla, J.
    Bundschuh, Jochen
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Geogenic arsenic and other trace elements in the shallow hydrogeologic system of Southern Poopó Basin, Bolivian Altiplano2013In: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336, Vol. 262, p. 924-940Article in journal (Refereed)
    Abstract [en]

    Environmental settings in the southern area of Lake Poopó in the Bolivian highlands, the Altiplano, have generated elevated amounts of arsenic (As) in the water. The area is characterised by a semiarid climate, slow hydrological flow and geologic formations of predominantly volcanic origin. The present study aimed at mapping the extent of the water contamination in the area and to investigate the geogenic sources and processes involved in the release of As to the groundwater.Ground- and surface-water samples were collected from 24 different sites, including drinking water wells and rivers, in the southern Poopó basin in two different field campaigns during the dry and rainy seasons. The results revealed variable levels of As in shallow drinking water wells and average concentration exceeding the WHO guidelines value. Arsenic concentrations range from below 5.2μg/L (the detection level) to 207μg/L and averages 72μg/L. Additionally, high boron (B) concentrations (average 1902μg/L), and high salinity are further serious concerns for deteriorating the groundwater quality and rendering it unsuitable for drinking. Groundwater is predominantly of the Na-Cl-HCO3 type or the Ca-Na-HCO3 type with neutral or slightly alkaline pH and oxidising character. While farmers are seriously concerned about the water scarcity, and on a few occasions about salinity, there are no concerns about As and B present at levels exceeding the WHO guidelines, and causing negative long term effects on human health.Sediment samples from two soil profiles and a river bed along with fourteen rock samples were also collected and analysed. Sequential extractions of the sediments together with the calculation of the mineral saturation indices indicate that iron oxides and hydroxides are the important secondary minerals phases which are important adsorbents for As. High pH values, and the competition of As with HCO3 and dissolved silica for the adsorption sites probably seems to be an important process for the mobilisation of As in the shallow groundwaters of the region. Continuous monitoring and expansion of monitoring systems are necessary prerequisites for better understanding of the pattern of As mobilisation in the Southern Poopó Basin.

  • 7. Quintanilla, J.
    et al.
    Ramos Ramos, O.E.
    Ormachea, Muñoz Mauricio
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Environmental Geochemistry and Ecotechnology.
    Garcia, M.E.
    Medina, H.
    Thunvik, Roger
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Environmental Management and Assessment.
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Environmental Geochemistry and Ecotechnology.
    Arsenic contamination, speciation and environmental consequences in the Bolivian plateau2009In: Natural Arsenic in Groundwater of Latin America: Occurrence, health impact and remediation, The Netherlands: CRC Press/Balkema , 2009, p. 91-100Chapter in book (Refereed)
  • 8.
    Ramos Ramos, Oswaldo Eduardo
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Cáceres, L.F.
    Ormachea Muñoz, Mauricio Rodolfo
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Quino, I.
    Quintanilla, J.
    Sracek, O.
    Thunvik, Roger
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Bundschuh, Jochen
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    García, M. E.
    Sources and behavior of arsenic and trace elements in groundwater and surface water in the Poopó Lake Basin, Bolivian Altiplano2012In: Environmental Earth Sciences, ISSN 1866-6280, Vol. 66, no 3, p. 793-807Article in journal (Refereed)
    Abstract [en]

    Water management in semiarid and arid catchments such as the Poopó Lake Basin requires improved understanding of the complex behavior of the various contaminants, which affect the drinking water quality and considered as crucial for sustainable development of the region. Mechanisms of arsenic (As) release in the surface and groundwater were studied. Hydrochemical data for surface water (4 samples) and groundwater (28 samples) were collected in a small watershed in the Poopó catchment at the highland of the Bolivian Andes (Altiplano). All of them show high electrical conductivity values and moderately oxidizing conditions. The surface water contains high concentration of sulfate and the trace elements As, Zn and Pb in the zone affected by acid mine drainage. There is a large variability of the concentration of As and of the trace elements in the groundwater in the five different regions within the Poopó catchment. The metal concentrations sensitive to changes of redox state and results of speciation modeling suggest that As (V) is a predominant aqueous species, which conforms to the prevailing oxidizing conditions in the shallow groundwater environment. Two generalized trends for As distribution were identified in groundwater: (a) high concentrations are found in the arid zone (100-250 Όg/L) in the southern (region III) and in the northwestern (region V) regions, and (b) low concentrations (< 50 Όg/L) are found in the remaining part of the basin (region I, II and IV). However, the spatial distribution within these regions needs to be investigated further. A conclusion from the present study is that there are multiple sources of As as well as other trace elements (such as Cd, Mn and Zn) in the Poopó Lake Basin. Among the sources and the processes which led to the mobility of As and other trace metals in the region are: (a) weathering of sulfide minerals, (b) oxidation of pyrite and/or arsenopyrite in mineralized areas and (c) desorption from hydrous ferric oxide (HFO) surfaces. In non-mining areas, volcanic ash is suggested to be a significant source of As.

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