Arsenic associations in sediments from the loess aquifer of La Pampa, Argentina

Smedley, Pauline; Kinniburgh, D.G.; Macdonald, David; Nicolli, Hugo; Barros, Aldre Jorge Morais; Tullio, J.O.; Pearce, Jonathan; Alonso, María Susana

doi:10.1016/j.apgeochem.2004.10.005

Cited by 210 publications

(144 citation statements)

References 36 publications

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“…The community is predominantly set upon Quaternary continental deposits of sand and loess (Lloret and Suvires 2006;DNGM, 1964). The geological composition of the sampling area may lead us to expect similar arsenic concentrations to those found in La Pampa (3 -1326 μg l -1 As), due to the environmental development of both regions during the Quaternary age (Smedley et al 2005;Bundschuh et al 2004;DNGM, 1964). However, the apparent variation in total arsenic between the two regions may be ascribed to differences in the natural environment.…”

Section: Discussionmentioning

confidence: 99%

“…The shallow groundwater aquifers in the Chaco-Pampean Plain of Argentina are a good example (Gomez et al 2009;Mukherjee et al 2008;Bundschuh et al 2004). High concentrations of total arsenic and other trace elements (B, F, Mo, V, U) have been reported to cause water-quality problems in aquifers from the provinces of Córdoba, Santa Fe and Buenos Aires, as well as La Pampa (Gomez et al 2009;Smedley et al 2005). …”

Section: Introductionmentioning

confidence: 99%

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Arsenic contamination of natural waters in San Juan and La Pampa, Argentina

O'Reilly

Watts

Shaw

et al. 2010

Environ Geochem Health

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Arsenic (As) speciation in surface and groundwater from two provinces in Argentina (San Juan and La Pampa) was investigated using solid phase extraction (SPE) cartridge methodology with comparison to total arsenic concentrations. A third province, Río Negro, was used as a control to the study. Strong cation exchange (SCX) and strong anion exchange (SAX) cartridges were utilised in series for the separation and preservation of arsenite (As ). Samples were collected from a range of water outlets (rivers/streams, wells, untreated domestic taps, well water treatment works) to assess the relationship between total arsenic and arsenic species, water type and water parameters (pH, conductivity and total dissolved solids, TDS). Analysis of the waters for arsenic (total and species) was performed by inductively coupled plasma mass spectrometry (ICP-MS) in collision cell mode. Total arsenic concentrations in the surface and groundwater from Encon and the San José de Jáchal region of San Juan (north-west Argentina within the Cuyo region) ranged from 9 -357 μg l -1As. Groundwater from Eduardo Castex (EC) and Ingeniero Luiggi (LU) in La Pampa (central Argentina within the Chaco-Pampean Plain) ranged from 3 -1326 μg l -1As. The pH range for the provinces of San Juan (7.2 -9.7) and La Pampa (7.0 -9.9) are in agreement with other published literature. The highest total arsenic concentrations were found in La Pampa well waters (both rural farms and pre-treated urban sources), particularly where there was high pH (typically > 8.2), conductivity (> 2600 μS cm As. Arsenic species for both provinces were predominantly As for groundwater, respectively. This translates to a relative As III abundance of 69 -100 % of the total arsenic in surface waters and 32 -100 % in groundwater. This is unexpected because it is typically thought that in oxidising conditions (surface waters), the dominant arsenic species is As V . However, data from the SPE methodology suggests that As III is the prevalent species in San Juan, indicating a greater influence from reductive processes. La Pampa groundwater had As (equating to up to 33 % of the total arsenic). Previously published literature has focused primarily on the inorganic arsenic species, however this study highlights the potentially significant concentrations of organoarsenicals present in natural waters. The potential for separating and preserving individual arsenic species in the field to avoid transformation during transport to the laboratory, enabling an accurate assessment of in-situ arsenic speciation in water supplies is discussed.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Arsenic contamination of natural waters in San Juan and La Pampa, Argentina

O'Reilly

Watts

Shaw

et al. 2010

Environ Geochem Health

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“…In addition, according to the fitting results, the influence of SDBS on As(V) adsorption was greater, while Triton X-100 showed greater effects on the adsorption of As(III) onto FH. Under the experimental pH conditions, As(V) existed mainly as anionic HAsO 4 2− , while As(III) existed as neutral H 3 AsO 3 (Smedley et al, 2005). According to the Zeta potential analysis, when the pH was approximately 7.0, the adsorption of SDBS caused a FH surface charge decrease from −1.49 mV to −39.6 mV, indicating that there could be electrostatic repulsion between SDBS and the negatively charged As(V).…”

Section: Adsorption Isotherm Of Arsenic In the Presence Of Surfactantsmentioning

confidence: 97%

Arsenic retention and transport behavior in the presence of typical anionic and nonionic surfactants

Liang

Wang

Peng

2016

Journal of Environmental Sciences

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The massive production and wide use of surfactants have resulted in a large amount of surfactant residuals being discharged into the environment, which could have an impact on arsenic behavior. In the present study, the influence of the anionic surfactant sodium dodecyl benzene sulfonate (SDBS) and nonionic surfactant polyethylene glycol octylphenyl ether (Triton X-100) on arsenic behavior was investigated in batch and column tests. The presence of SDBS and Triton X-100 reduced arsenic retention onto ferrihydrite (FH), enhanced arsenic transport through FH coated sand (FH-sand) columns and promoted arsenic release from the FH surface. With coexisting surfactants in solution, the equilibrium adsorbed amount of arsenic on FH decreased by up to 29.7% and the adsorption rate decreased by up to 52.3%.Pre-coating with surfactants caused a decrease in the adsorbed amount and adsorption rate of arsenic by up to 15.1% and 58.3%, respectively. Because of the adsorption attenuation caused by surfactants, breakthrough of As(V) and As(III) with SDBS in columns packed with FH-sand was 23.8% and 14.3% faster than that in those without SDBS, respectively. In columns packed with SDBS-coated FH-sand, transport of arsenic was enhanced to a greater extent.Breakthrough of As(V) and As(III) was 52.4% and 43.8% faster and the cumulative retention amount was 44.5% and 57.3% less than that in pure FH-sand column systems, respectively.Mobilization of arsenic by surfactants increased with the increase of the initial adsorbed amount of arsenic. The cumulative release amount of As(V) and As(III) from the packed column reached 10.8% and 36.0%, respectively.

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“…A population of more than 1.2 million in rural Argentina depends on groundwater where As concentration exceeds the WHO guideline as well as the national drinking water standard of 10 μg/L [77,78]. The most affected regions are extensive areas of the Pampean Plain, some parts of the Chaco Plain, and some small areas of the Andean range, where drinking water wells contain 50 to 15, 000 μg/L of As [30,46,70,[76][77][78][79][80][81][82][83]. The sedimentary aquifers in this region comprise Tertiary aeolian loess-type sediments in the Pampean Plain and predominantly fluvial sediments of Tertiary and Quaternary age in the Chaco region.…”

Section: Latin Americamentioning

confidence: 99%

“…The sedimentary aquifers in this region comprise Tertiary aeolian loess-type sediments in the Pampean Plain and predominantly fluvial sediments of Tertiary and Quaternary age in the Chaco region. Drinking water for the rural populations is supplied by the shallow aquifers and contains around 200 μg/L of As (nearly 30 % as As) as well as high concentrations of fluoride (2.1 mg/L) [30,46,70,[76][77][78][79][80][81][82][83].…”

Section: Latin Americamentioning

confidence: 99%

Natural Arsenic in Global Groundwaters: Distribution and Geochemical Triggers for Mobilization

et al. 2016

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The elevated concentration of arsenic (As) in the groundwaters of many countries worldwide has received much attention during recent decades. This article presents an overview of the natural geochemical processes that mobilize As from aquifer sediments into groundwater and provides a concise description of the distribution of As in different global groundwater systems, with an emphasis on the highly vulnerable regions of Southeast Asia, the USA, Latin America, and Europe. Natural biogeochemical processes and anthropogenic activities may lead to the contamination of groundwaters by increased As concentrations. The primary source of As in groundwater is predominantly natural (geogenic) and mobilized through complex biogeochemical interactions within various aquifer solids and water. Sulfide minerals such as arsenopyrite and As-substituted pyrite, as well as other sulfide minerals, are susceptible to oxidation in the near-surface environment and quantitatively release significant quantities of As in the sediments. The geochemistry of As generally is a function of its multiple oxidation states, speciation, and redox transformation. The reductive dissolution of As-bearing Fe(III) oxides and sulfide oxidation are the most common and significant geochemical triggers that release As from aquifer sediments into groundwaters. The mobilization of As in groundwater is controlled by adsorption onto metal oxyhydroxides and clay minerals. According to recent estimates, more than 130 million people worldwide potentially are exposed to As in drinking water at levels above the World Health Organization's (WHO's) guideline value of 10 μg/L. Hence, community education to strengthen public awareness, the involvement and capacity building of local stakeholders in targeting As-safe aquifers, and direct action and implementation of best practices in identifying safe groundwater sources for the installation of safe drinking water wells through action and enforcement by local governments and international water sector professionals are urgent necessities for sustainable As mitigation on a global scale.

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Arsenic associations in sediments from the loess aquifer of La Pampa, Argentina

Cited by 210 publications

References 36 publications

Arsenic contamination of natural waters in San Juan and La Pampa, Argentina

Arsenic contamination of natural waters in San Juan and La Pampa, Argentina

Arsenic retention and transport behavior in the presence of typical anionic and nonionic surfactants

Natural Arsenic in Global Groundwaters: Distribution and Geochemical Triggers for Mobilization

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