1,323 research outputs found
The global arsenic crisis - a short introduction
No full textIn order to understand the worldwide importance of the problem of high arsenic (As) concentrations in waters used for drinking water supplies, and the corresponding mitigation strategies, it is useful to analyze the history of the detection of As in water resources, starting at the end of the 19th century to the situation today. Characterizing the conditions under which As releasing aquifers occur or how As is released into surface water, is the starting point for the formulation of sustainable mitigation solutions, such as As removal from drinking water or zero-treatment options. This historical perspective can have relevance to emerging water resource issues related to As. As well as the biogeochemical factors that give rise to elevated As in water resources, political, social and economic reasons are also relevant.
For example, in Bangladesh the acceptance of many remediation projects by the local population has not been sufficiently considered resulting in the failure of efforts to mitigate arsenic exposure
Arsenic contamination in groundwaters in Bangladesh and options of sustainable drinking water supplies
No full textGroundwater sources used for drinking in many parts of the world contain geogenic arsenic (As) with levels of concentrations above the drinking water guideline value of the World Health Organisation (WHO, 10 iJg L-1). Occurrence of arsenic in groundwater has been known a century ago from Argentina, where the toxic effects on public health were described already in the year 1917. However, it was not before half a century later, that the As problem achieved world interest. This was the consequence of a UNICEF program to provide the rural population of Bangladesh with microbe-free drinking water by changing the drinking
water resource from surface- and rainwater to groundwater exploited from shallow aquifers. However, the quality of the groundwater was not tested for As and caused, after 10 years of exposure of large parts of the population, toxicological effects. This became the beginning
of extended international aid efforts to mitigate the As problem in Bangladesh and adjacent West-Bengal, India, where many treatment methods have been developed and tested, and brought the groundwater As topic to wide scientific and public interest.
Since several decades, the contamination of groundwater and to less extent of surface water by geogenic As is well known from countries such as Mexico, Chile, Peru, Taiwan and some small regions in European countries such as Hungary. Until recently, it was thought that the problem is limited to these countries. However, there were many new discoveries all over the world such as in several regions of the People's Republic of China (1993- 1996), Nicaragua
(1996), Chhattisgarh, India (1999), Nepal (2000), Bolivia (2001) , Thailand (2001), Vietnam (2001), Australia (2001); Bihar, India (2002), Uttar Pradesh, India (2003), Jharkhand,
India (2004), Assam, India (2004) , Myanmar (2004), Cambodia (2004), Pakistan (2005), El Salvador (2005), Ecuador (2005), Honduras (2006), Baja California State, Mexico (2006), Lao People's Democratic Republic (2006), Cambodia (2007), Manipur, India (2007), and more recently in Sumatra, Indonesia (2009) and Izmir province, Turkey (2009) (Fig. 1.1 in chapter 1 of this book)
Targeting arsenic-safe aquifers for drinking water supplies
No full textAt present, 70 countries worldwide are affected by groundwater contamination by arsenic (As) released from predominantly geogenic sources. Consequently, the As problem is becoming a global issue. The option to target As-safe aquifers, which uses geological, geochemical, hydrogeological, morphological and climatic similarities to delimit As-safe aquifers, appears as a sustainable mitigation option. Two pilot areas, Meghna Flood Plain in Matlab Upazila, representative of Bengal Delta in Bangladesh, and Río Dulce Alluvial Cone, representing a typical aquifer setting in the Chaco-Pampean Plain in Argentina groundwater As occurrence, were compared. In rural Bangladesh, As removal techniques have been provided to the population, but with low social acceptance. In contrast, targeting As-safe aquifers was socially accepted in Bangladesh, where sediment color could be used to identify As-safe aquifer zones and to install safe wells. The investigation in Argentina is more complex because of very different conditions and sources of As. Targeting As-safe aquifers could be a sustainable option for many rural areas and isolated peri-urban areas.Fil: Bundschuh, Jochen. Royal Institute of Technology; SueciaFil: Litter, Marta Irene. Universidad Nacional de San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bhattacharya, Prosun. Royal Institute of Technology; Sueci
32nd International Geological Congress
No full textNatural occurrences of arsenic has been documented in groundwater of the shallow aquifers of the Chaco-Pampean Plain, Argentina. The distribution of arsenic and mechanisms of its mobilization in the shallow alluvial aquifers was investigated around the city of Santiago del Estero in Northwestern Argentina in order to provide an insight into the complex hydrological and geochemical conditions that yields high As concentrations in groundwater. Significant spatial variations of total arsenic (Astot) concentrations were observed with an average value of 743g/L. Arsenate was a dominant species in most samples. Average concentrations of Al, Mn, and Fe were 360g/L, 574g/L, and 459g/L, respectively. The 7M HNO3 extraction of sediments and volcanic ash-layer indicated AsNO3 concentrations ranging between 2.5-7.1 mg/kg. AsNO3 indicated a significant positive correlation with MnNO3, AlNO3, and FeNO3. Oxalate extractions revealed significant fractions of As (Asox) in the sediments (0.4-1.4 mg/kg) and a dominance of oxalate extractable Al-and Mn. Speciation calculations indicate that Al oxide and hydroxides have the potential to precipitate in the groundwater, suggesting that As adsorption processes may be to some extent controlled by Al oxides and hydroxides. Mobility of As at local scale seems to depend on high pH values, related to the dissolution of carbonates driven by cation exchange, and dissolution of silicates. There is a clear relationship of As with F, V, B and Si, suggesting their common origin in volcanic ash layer. Preliminary conceptual model of arsenic input includes release of As and Al from dissolution of volcanic ash layer, precipitation of Al oxides and hydroxides followed by adsorption of As on Al and Fe phases in sediments, and release of As under high pH conditions
Inlist files for "Detectability of axisymmetric magnetic fields from the core to the surface of oscillating post-main sequence stars"
No full text<p>Concerned article: "Detectability of axisymmetric magnetic fields from the core to the surface of oscillating post-main sequence stars" by Bhattacharya et al. (submitted).<br>Corresponding author: Shatanik Bhattacharya</p>
<p>Inlists for the proof-of-concept stellar models used in this project have been provided here for reproducibility.</p>
<p>For the red-giant model, the inlist was executed with MESA version r22.05.1 and MESA-SDK version x86 64-linux-22.6.1. Model 500 (age 4.056 Gyr) was used as the RG in this project.</p>
<p>For the sub-giant models, the inlist was executed with MESA version r23.05.1 and MESA-SDK version x86 64-linux-22.6.1. Models 345 (age 3.624 Gyr) and 350 (age 3.702 Gyr) were used as the MSG and LSG models respectively.</p>
Arsenic in the environment: Biology and Chemistry
No full textCrown copyright © 2007 Published by Elsevier B.V.Arsenic (As) distribution and toxicology in the environment is a serious issue, with millions of individuals worldwide being affected by As toxicosis. Sources of As contamination are both natural and anthropogenic and the scale of contamination ranges from local to regional. There are many areas of research that are being actively pursued to address the As contamination problem. These include new methods of screening for As in the field, determining the epidemiology of As in humans, and identifying the risk of As uptake in agriculture. Remediation of As-affected water supplies is important and research includes assessing natural remediation potential as well as phytoremediation. Another area of active research is on the microbially mediated biogeochemical interactions of As in the environment. In 2005, a conference was convened to bring together scientists involved in many of the different areas of As research. In this paper, we present a synthesis of the As issues in the light of long-standing research and with regards to the new findings presented at this conference. This contribution provides a backdrop to the issues raised at the conference together with an overview of contemporary and historical issues of As contamination and health impacts.Prosun Bhattacharya, Alan H. Welch, Kenneth G. Stollenwerk, Mike J. McLaughlin, Jochen Bundschuh and G. Panaullahhttp://www.elsevier.com/wps/find/journaldescription.cws_home/503360/description#descriptio
The Unique Altiplano-Puna Plateau: Environmental Perspectives
No full textThe Altiplano-Puna is a distinctive plateau and pristine environment to study geochemical, ecological, and climatic phenomena. It is the second highest plateau on Earth after Tibet and contains the largest endorheic system of South America. Nevertheless, water is a vital resource in the region, and surface water and groundwater are essential sources of drinking water for inhabitants. Environmental characterizations in the Altiplano-Puna plateau are fairly new and increasingly important due to climate change, the sustained decrease of surface water bodies (e.g. Lake Poopó), as well as anthropogenic and natural contaminants (e.g. arsenic) which can pollute the scarce water resources. Despite extreme and unique climatic, hydrologic, and geochemical conditions of the Altiplano-Puna plateau, some indigenous populations and biota have adapted. This Special Issue presents seven original research papers covering a wide range of topics in the Altiplano-Puna related to hydrogeochemical, climatic, and anthropogenic processes on the origin and mobility of economically important elements and contaminants, as well as environmental issues and bioindicators of ecological conditions in surface waters. Its aim is to present new and comprehensive analyses with interpretations in this extreme, yet pristine area which has been scarcely characterized from an environmental perspective, and also inspire future studies in the region.Fil: Tapia, Joseline. Universidad Católica del Norte; ChileFil: Murray, Jesica María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta-Jujuy. Instituto de Bio y Geociencias del Noroeste Argentino. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto de Bio y Geociencias del Noroeste Argentino; ArgentinaFil: Ormachea Muñoz, Mauricio. Universidad Mayor de San Andrés; BoliviaFil: Bhattacharya, Prosun. Royal Institute of Technology; Sueci
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