Groundwater Arsenic Contamination, Its Health Impact and Mitigation Program in Nepal

Shrestha, Roshan Raj; Shrestha, Marina Vaidya; Upadhyay, Narayan P; Pradhan, Riddhi; Khadka, Rosha; Maskey, Arinita; Maharjan, Makhan; Tuladhar, Sabita; Dahal, Binod M.; Shrestha, Kabita

doi:10.1081/ese-120016888

Cited by 139 publications

(57 citation statements)

References 2 publications

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“…3 Primary potable water supplies are contaminated in many rural areas and developing countries like Bangladesh, India, and Nepal, where the arsenic level has remained at 50 μg/L. 4,5 Bangladesh is in a severe situation, with 35−77 million of its citizens potentially exposed to water with arsenic levels above the recommended limit of the World Health Organization (WHO), which is 10 μg/L. 6,7 Facing the technical and economic challenges associated with achieving this standard, the development of novel technologies to remove arsenic contaminants from water in a sustainable and economical way is of great importance.…”

Section: ■ Introductionmentioning

confidence: 99%

Removal of Arsenic and Phosphate from Aqueous Solution by Metal (Hydr-)oxide Coated Sand

Huang

Yang

Keller

2014

ACS Sustainable Chem. Eng.

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Arsenic contamination is a major concern in many drinking water supplies around the world. One low-cost approach for removing arsenic and other oxyanions such as phosphate is to use metal (hydro-)oxide coated sands. In this study, solution pH, sand grain size, coating efficiency, and mineral type for iron-coated sand (ICS), manganese-coated sand (MCS), and iron-and manganese-coated sand (IMCS) were evaluated. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis were used to investigate the surface properties of the coated layer. The mineral type of ICS prepared at different solution pH was identified as a mixture of FeOOH and Fe 2 O 3 . The mineral type of MCS prepared at pH 4 and 7 was identified as MnO 2 and changed to ramsdellite (γ-MnO 2 , a mixture of α-MnO 2 and β-MnO 2 ) at pH 10. ICS exhibited a greater phosphate removal capacity, and phosphate removal increased with increasing iron oxide on the sand. ICS was also shown to have a greater removal capacity for phosphate than chemical precipitation methods by FeCl 3 , especially below neutral pH. In contrast, IMCS(Fe:Mn = 7:3) was better for removing As(III), which occurs through oxidation to As(V) and adsorption of As(III) and As(V) and can reach >98% removal rate (residual concentration <0.02 mg/L) at neutral pH. IMCS(7:3) is an efficient adsorbent for arsenic, as >50% can be removed within 60 min; 66% adsorption was reached after 24 h. Removal of arsenic and phosphate by these metal (hydro-)oxide coated sand adsorbents followed a pseudo-second-order rate and Langmuir as well as Freundlich adsorption isotherms. Removal under different conditions (e.g., pH, ionic strength) was also evaluated to provide information to optimize the process.

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Section: ■ Introductionmentioning

confidence: 99%

Removal of Arsenic and Phosphate from Aqueous Solution by Metal (Hydr-)oxide Coated Sand

Huang

Yang

Keller

2014

ACS Sustainable Chem. Eng.

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“…3 India, 11 New Zealand, 12 Taiwan 13 and Vietnam 14 have the same 10 ppb level of arsenic as a maximum permissible limit for the drinking water. Bangladesh, 15 Nepal, 16 Argentina, 17 China, 18 Chile 19 and Mexico 20 have regulated 50 ppb of arsenic as a maximum level of contamination in the drinking water. These new regulations make water facilities face challenging financial burdens or even incapable of reaching the newly proposed MCL for arsenic, unless affordable methods of arsenic removal are developed.…”

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confidence: 99%

Magnetic Graphene Nanoplatelet Composites toward Arsenic Removal

Zhu

Sadu

Wei

et al. 2012

ECS J. Solid State Sci. Technol.

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Magnetic graphene nanoplatelet composites (MGNCs) decorated with core-shell Fe-Fe 2 O 3 nanoparticles (NPs) have been synthesized using a facile one-pot thermal decomposition method. The graphene nanoplatelets (GNPs) decorated with uniformly dispersed NPs are observed to exhibit a strong magnetization and can be magnetically separated from the liquid mixture by a permanent magnet. These MGNCs demonstrate an effective and efficient adsorption of arsenic(III) in the polluted water due to the increased adsorption sites in the presence of magnetic NPs. The adsorption behavior is well fitted with both Langmuir and Freundlich models, which show a significantly higher adsorption capacity (11.34 mg/g) than the other adsorption values reported on the conventional iron oxide based adsorbents (∼1 mg/g). The results show a nearly complete As(III) removal within 1 ppb. © 2012 The Electrochemical Society. [DOI: 10.1149/2.010201jss] All rights reserved.Manuscript received March 8, 2012. Published July 17, 2012 Arsenic is known for its toxicity and carcinogenicity to human beings, 1-3 the contaminated water with arsenic is becoming a significantly increasing issue in drinking water throughout the world. Longterm exposure to arsenic can cause cancers of the bladder, lungs, skin, kidney, liver and prostate. 4 Arsenic contaminates include both natural and anthropogenic sources. Anthropogenic arsenic pollutants originate from mining and smelting of non-ferrous metals, burning of fossil fuels, usage of arsenic-containing pesticides in the agriculture 5 and arsenic-containing chemicals in the preservation of timber.6 Arsenic can exit in both inorganic and organic forms. In general, inorganic arsenic compounds are more toxic than organic arsenic compounds, and arsenite [As(III)] is considerably more mobile and toxic than arsenate [As(V)].7 Arsenate (i.e., HAsO 4 2− ) is the primary anion in the aerobic surface water and arsenite (i.e., H 3 AsO 3 or H 2 AsO 3 − ) is the primary species in the ground water. The actual valence states and chemical form, however, depend on the redox environments in the water systems including pH, oxidation-reduction potential, and the presence of complexing ions. There are several requirements that need to be met for arsenic removal such as safe and easy operation, high efficiency and low cost.7 Compared to the conventional water treatment techniques including oxidation/precipitation, 21 membrane/reverse osmosis, coagulation/coprecipitation, 22 and ion exchange, 7 adsorption has the following advantages. For example, it does not need a large volume or additional chemicals for treatment and it is easier to be deployed * Electrochemical Society Active Member.z E-mail: suying.wei@lamar.edu; zhanhu.guo@lamar.edu as a Point of Entry/Point of Use (POE/POU) arsenic removal process. Moreover, adsorption processes produce no sludge as met in the coagulation approach 7 and it does not need a strict control of pH values as met in the oxidation process.23 Adsorption can be dealt with low cost medium, low-tech operatio...

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“…The Ministry of Environment of Nepal has done a survey regarding presence of phenylarsenic oxide (PAO) in soil and water in Terai (Southern) belt region of Nepal. 6 However, similar studies concerning PAO have not been conducted in the Siwalik/Chure (mountainous) region of Nepal. Moreover, we could not find other patients with BD in Ramechap district.…”

Section: Discussionmentioning

confidence: 99%

“…Usually organic arsenic is a highly stable chemical but in the environment it can oxidize and dissolve in water and thence pollute ground water. 5 Water from wells have high percentage of arsenic.…”

Section: Discussionmentioning

confidence: 99%