Arsenic distribution along different hydrogeomorphic zones in parts of the Brahmaputra River Valley, Assam (India)

The spatial distribution of arsenic (As) concentrations along three classified hydrogeomorphological zones in the Brahmaputra River Valley in Assam (India) have been investigated: zone I, comprising the piedmont and alluvial fans; zone II, comprising the runoff areas; and zone III, comprising the discharge zones. Groundwater (150 samples) from shallow hand-pumped and public water supply wells (2–60 m in depth) was analysed for chemical composition to examine the geochemical processes controlling As mobilization. As concentrations up to 0.134 mg/L were recorded, with concentrations below the World Health Organization and the Bureau of Indian Standards drinking-water limits of 0.01 mg/L being found mainly in the proximal recharge areas. Eh and other redox indicators (i.e., dissolved oxygen, Fe, Mn and As) indicate that, except for samples taken in the recharge zone, groundwater is reducing and exhibits a systematic decrease in redox conditions along the runoff and discharge zones. Hydrogeochemical evaluation indicated that zone I, located along the proximal recharge areas, is characterized by low As concentration, while zones II and III are areas with high and moderate concentrations, respectively. Systematic changes in As concentrations along the three zones support the view that areas of active recharge with high hydraulic gradient are potential areas hosting low-As aquifers

Investigation of a cholera outbreak in a tea garden of Sivasagar district of Assam

Background: In late May 2012, Bagjan division of Borbam tea estate, of Sivasagar district of Assam was affected by an outbreak of acute watery diarrhea, subsequently confirmed as Vibrio cholerae O1. Objectives: Our objective is to investigate and control the acute diarrheal disease outbreak in Sivasagar district of Assam. Materials and Methods: A physician-epidemiologist-led team did rapid outbreak investigation to confirm the outbreak and instituted treatment and control measures. Quantitative data collection was done using standard schedule and qualitative data by using key informant interview schedule. Results: Spot mapping of cases was done along the garden residential lines. About 120 suspected cases were line listed; with 1:1.23 male: female ratio. Ages ranged from 3 to 70 years (median - 40.5 years). Attack rate was 4.79% with one death; case fatality rate was 0.83%. Open air defecation was practiced by 94.6%. Rectal swabs were positive for V. cholerae O1 (Ogawa). All the piped water samples were class IV unsatisfactory for domestic use. Conclusions: There is a need to improve water and sanitation facility in the tea garden lines along with implementation of a strengthened disease surveillance system through integrated disease surveillance project covering all tea estates

Solute chemistry and groundwater arsenic enrichment in southern part of Brahmaputra River Basin, India, adjacent to Indo-Burmese ranges

© 2016 Taylor & Francis Group, London. The present study examines the groundwater chemistry, hydrogeochemical evolution and Arsenic (As) enrichment in shallow aquifers in the southern Brahmaputra river basin situated close to Naga-thrust belt. The major-ion composition dominated by a Na?Ca?HCO3 and Ca?Na?HCO3 hydro-chemical facies. Groundwater composition influenced by silicates weathering in S-region of Brahmaputra basin aquifers. The aquifers of S-region are severely contaminated with As (max 0.45 mg/L), nearly 92% collected groundwater sample are enriched with As. As show poor and negative correlation with various redox—sensitive solutes. It suggests that not a single process is controlling factor, although multiple biogeochemical mechanisms might influence As liberation and fate in groundwater of S-region. The geologic explanation for high arsenic in the southern region of Brahmaputra basin (upper Assam) is probably the crustal recycling of arsenic as an incompatible element during tectonic activity

Microwave assisted and in-situ generated palladium nanoparticles catalysed desulfitative synthesis of cross-biphenyls from arylsulfonyl chlorides and phenylboronic acids

A microwave assisted reaction protocol for Suzuki–Miyaura cross-coupling has been developed. Substituted arylboronic acids and arylsulfonyl chlorides coupled under microwave irradiation (MWI) to produce cross-biphenyls in high yields under aerobic condition. The principal advantage of this protocol is that formation of cross-biphenyls was achieved within shorter time along with desulfurization of arylsulfonyl chloride. In-situ generated Pd nanoparticles (NPs) act as catalyst in the reaction. Substituents like methyl, halogens, cyano, amino and t-butyl groups in arylboronic acids tolerate the reaction condition. Pd NPs could be reused several times under chosen reaction conditions without losing its activity significantly. The product formation and the role of the catalyst for the cross-coupling reaction has been rationalised with the help of a proposed mechanism. This reaction is one of the examples of In-situ generated Nanoparticles-catalyzed Organic Synthesis Enhancement (i-NOSE) approach. The approach derives its importance in terms of catalyst’s (i) simple preparation method, (ii) stability under the chosen reaction condition, (iii) substrate specificity, (iv) simple filtration to recover the catalyst and (v) easy regeneracy which clearly indicate that the approach could be applicable for various types of catalytic transformations.Bio4Energ

Contrasting controls on hydrogeochemistry of arsenic-enriched groundwater in the homologous tectonic settings of Andean and Himalayan basin aquifers, Latin America and South Asia

High groundwater arsenic (As) across the globe has been one of the most well researched environmental concerns during the last two decades. Consequently, a large scientific knowledge-base has been developed on As distributions from local to global scales. However, differences in bulk sediment As concentrations cannot account for the As concentration variability in groundwater. Instead, in general, only aquifers in sedimentary basins adjacent to mountain chains (orogenic foreland basins) along continental convergent tectonic margins are found to be As-enriched. We illustrate this association by integrating observations from long-term studies of two of the largest orogenic systems (i.e., As sources) and the aquifers in their associated foreland basins (As sinks), which are located in opposite hemispheres and experience distinct differences in climate and land-use patterns. The Andean orogenic system of South America (AB), an active continental margin, is in principle a modern analogue of the Himalayan orogenic system associated with the Indus-Ganges-Brahmaputra river systems in South Asia (HB). In general, the differences in hydrogeochemistry between AB and HB groundwaters are conspicuous. Major-solute composition of the arid, oxic AB groundwater exhibits a mixed-ion hydrochemical facies dominated by Na-Ca-Cl-SO4-HCO3. Molar calculations and thermodynamic modeling show that although groundwater of AB is influenced by cation exchange, its hydrochemical evolution is predominated by feldspar dissolution and relationships with secondary clays. In contrast, humid, strongly reducing groundwater of HB is dominated by Ca-HCO3 facies, suggestive of calcite dissolution, along with some weathering of silicates (monosiallitization). This work demonstrates that although hydrogeochemical evolutionary trends may vary with local climate and lithology, the fundamental similarities in global tectonic settings can still lead to the elevated concentrations of groundwater As

Contemporary groundwater pollution studies in India

This review contains a summary of the work done on arsenic and flouride pollution of the surface and groundwater in parts of the Indian peninsula and Ganga-Brahmaputra Alluvial and Delta Plains. Results of the investigation have been be categorized institutions wise with identification of the principal worker in the research group. © Printed in India

Influence of geology on groundwater–sediment interactions in arsenic enriched tectono-morphic aquifers of the Himalayan Brahmaputra river basin

The present study interprets the groundwater solute chemistry, hydrogeochemical evolution, arsenic (As) enrichment and aquifer characterization in Brahmaputra River Basin (BRB) involving three geologically and tectono-morphically distinct regions located in northeastern India. These study regions consist of the northwestern (NW) and the northern (N) region, both located along the western and eastern parts of Eastern Himalayas and the southern (S) region (near Indo–Burmese Range and Naga hills) of the Brahmaputra basin which show distinct tectonic settings and sediment provenances in the Himalayan orogenic belt. Stable isotopic composition (d2H and d18O) in groundwater suggests that some evaporation may have taken place through recharging of ground water in the study areas. The major-ion composition shows that groundwater composition of the NW and N parts are between [Formula presented]3 and [Formula presented]3 while the S-region is dominated by [Formula presented]3 hydrochemical facies. The major mineralogical composition of aquifer sediments indicates the dominant presence of iron(Fe)-oxide and oxyhydroxides, mica (muscovite and biotite), feldspar, pyroxene, amphibole, abundance of quartz and clay minerals whereas clay is predominantly present in sediments of S-aquifers. These mafic minerals, aluminosilicates and clay minerals might offer available reactive surface for As-adsorption and co-precipitatation with amorphous Fe. These associated adsorbed and co-precipitated As might be released due to reductive dissolution of Fe-oxide and oxyhydroxides in groundwater. These minerals are assumed to be possible sources of As in groundwater. The stability diagrams of groundwater data suggest that solute might have been introduced into groundwater from weathering of K-feldspar, plagioclase, pyroxene of Himalayan rocks, the Siwalik Group and Eastern Syntaxes in NW and N-regions. However, basic cations might be derived from weathering of K-feldspar, plagioclase, pyroxene and olivine those being major constituents in a gabbroic complex (ophiolite) and basalt terrain in S-region. The aquifers of S-region are severely contaminated with dissolved As compared to NW and N regions. Almost more than 92% of groundwater samples in the southern part (maximum 5.53 µM or 415 µg/L) are enriched with As, which draws a distinct difference from the NW and N parts of BRB aquifers. The redox-sensitive solutes (i.e., Fe, Mn, HCO3- and TOC) are positively correlated with As in NW and N-parts; whereas EH shows negative to very weak positive correlation which suggests that a redox-dependent mobilization plays important role in As liberation in NW and N parts of the basin. However, As in southern aquifers is not showing any correlation or weak negative correlation with redox-sensitive solutes; suggesting that multiple reactions and hydrogeochemical processes and their interaction control As mobilization and fate in the S-region of BRB. The occurrence of high concentrations of arsenic in groundwater of Brahmaputra basin is described through a crustal recycling model and tectonic movement between the Indian–Eurasian plates and Burmese micro-continents. As-enriched groundwater in Himalayan foreland basin in the BRB is probably a result of crustal evolution through which As is subsequently mobilized from aquifer matrix to solution in groundwater by water–sediment reaction under favorable biogeochemical conditions. The results of the study indicate geological control (i.e. change in lithofacies, tectonic set-up) on groundwater chemistry and distribution of redox-sensitive solutes such as As

National noncommunicable disease monitoring survey (NNMS) in India: Estimating risk factor prevalence in adult population.

BackgroundThe primary objective of National NCD monitoring survey (NNMS) was to generate national-level estimates of key NCD indicators identified in the national NCD monitoring framework. This paper describes survey study protocol and prevalence of risk factors among adults (18-69 years).Materials and methodsNNMS was a national level cross-sectional survey conducted during 2017-18. The estimated sample size was 12,000 households from 600 primary sampling units. One adult (18-69 years) per household was selected using the World Health Organization-KISH grid. The study tools were adapted from WHO-STEPwise approach to NCD risk factor surveillance, IDSP-NCD risk factor survey and WHO-Global adult tobacco survey. Total of 8/10 indicators of adult NCD risk factors according to national NCD disease monitoring framework was studied. This survey for the first time estimated dietary intake of salt intake of population at a national level from spot urine samples.ResultsTotal of 11139 households and 10659 adults completed the survey. Prevalence of tobacco and alcohol use was 32.8% (95% CI: 30.8-35.0) and 15.9% (95% CI: 14.2-17.7) respectively. More than one-third adults were physically inactive [41.3% (95% CI: 39.4-43.3)], majority [98.4% (95% CI: 97.8-98.8)] consumed less than 5 servings of fruits and / or vegetables per day and mean salt intake was 8 g/day (95% CI: 7.8-8.2). Proportion with raised blood pressure and raised blood glucose were 28.5% (95% CI: 27.0-30.1) and 9.3% (95% CI: 8.3-10.5) respectively. 12.8% (95% CI: 11.2-14.5) of adults (40-69 years) had ten-year CVD risk of ≥30% or with existing CVD.ConclusionNNMS was the first comprehensive national survey providing relevant data to assess India's progress towards targets in National NCD monitoring framework and NCD Action Plan. Established methodology and findings from survey would contribute to plan future state-based surveys and also frame policies for prevention and control of NCDs