Central-east India Research Articles

A Model of Transformational Learning for Early Childhood Community-based Workers: Sajag Training for Responsive Caregiving

A global goal for early childhood education and care is to ensure universal, “quality” provision that reaches all children. Achieving this goal requires a well-prepared workforce that is equipped to adapt to and deliver early childhood programs across the vastly diverse contexts and communities where children are growing up around the world. Yet currently there is a severe shortage of early childhood workers, particularly in “low resource” and complex communities. Evidence to support appropriate training for such workers is also lacking. In response, this paper presents findings from a case study of a large-scale training program for community-based early childhood workers in central-east India. A total of 650 community-based Village Communicators were trained to deliver a responsive caregiving package to parents of young children. Data collected over 3 months highlight how the unique contextually grounded, caring and reflexive approach to training resulted in profound personal and professional change among training participants. The findings are of significance in informing policy and practice associated with global goals for early childhood. First, they challenge the technical, programmatic approaches to training that are commonly adopted for preparing this workforce. Second, they evidence the potentially transformative, long-term impact of person-centered approaches to training that facilitate knowledge-sharing to understand local needs and attitudes. Third, they provide insight into ways in which training programs can support enhanced local relevance and effectiveness of early childhood services implemented for children and families across diverse contexts.

Tracing the Origin of the South Asian Summer Monsoon Precipitation and Its Variability Using a Novel Lagrangian Framework

AbstractThe water sources and their variability responsible for the South Asian summer monsoon precipitation were analyzed using Lagrangian atmospheric water-mass trajectories. The results indicated that evaporated waters from the central and south Indian Ocean are the major contributors to the South Asian summer monsoon rainfall, followed by the contribution from the local recycling (precipitated water that evapotranspirated from the South Asian landmass), the Arabian Sea, remote sources, and the Bay of Bengal. It was also found that although the direct contribution originating from the Bay of Bengal is small, it still provides a pathway for the atmospheric water that comes from other regions. This pathway is hence only crossing over the Bay of Bengal. The outcomes further revealed that the evaporated waters originating from the central and south Indian Ocean are responsible for the net precipitation over the coastal regions of the Ganges–Brahmaputra–Meghna Delta, northeast India, Myanmar, the foothills of the Himalayas, and central-east India. Evaporated waters from the Arabian Sea are mainly contributing to the rainfall over the western coast and west-central India. Summer monsoon precipitation due to the local recycling is primarily restricted to the Indo-Gangetic plain. No recycled precipitation was observed over the mountain chain along the west coast of India (Western Ghats). The month-to-month precipitation variation over South Asia was analyzed to be linked with the Somali low-level jet variability. The interannual variability of the South Asian summer monsoon precipitation was found to be mainly controlled by the atmospheric waters that were sourced and traveled from the central and south Indian Ocean.

Temporal variability of atmospheric particulate-bound polycyclic aromatic hydrocarbons (PAHs) over central east India: sources and carcinogenic risk assessment.

Atmospheric polycyclic aromatic hydrocarbons (PAHs) are of significant interest owing to their high potential health effects, including mutagenicity and carcinogenicity. We report 16 PAHs measured in ambient PM2.5 from June 2018 to May 2019 over three different sites located in central east India. The annual average PM2.5 mass concentrations of 97.3 ± 18.1 µg m−3, 101.9 ± 19.4 µg m−3, and 93.9 ± 20.3 µg m−3 were measured at RCI (Ranchi), GHY (Gamharia), and BKR (Bokaro), respectively. The mass concentrations at all sampling sites are relatively higher than the annual average concentration of the National Ambient Air Quality Standard. Total annual PAH concentrations (ng m−3) are found to be comparable at BKR (797.9 ± 39.1 ng m−3) and RCI (887.7 ± 38.8 ng m−3); however, a relatively higher average is observed over GHY (1015.1 ± 42.7 ng m−3). Using PAH diagnostic ratios and principal component analysis (PCA), their major sources were attributed to coal and wood combustion as well as vehicular emission of diesel and gasoline at all sampling sites. Significant seasonal variability is observed for PAH composition and mainly attributed to change in emission sources. Summer and winter compositions were found to be impacted by the transport from Indo-Gangetic Plains (IGP). However, ambient level PAHs during the post-monsoon season were impacted by mixed sources from Indo-Gangetic Plain and eastern India. These observations are supported by the analysis of back-trajectory and fire count data. The excess life time cancer risk (ELCR) values estimated for the study sites are within acceptable limits suggesting acceptable risk levels at BKR, GHY, and RCI. This study highlights the significance of ambient aerosol concentration for health risks in the pre-COVID-19 scenario.Graphical

Classical hydraulic ram pump performance in comparison with modern hydro-turbine pumps for low drive heads

We present a unique comparison of two types of renewable hydro pumping devices, namely the ram and turbine pump having different working principles. This comparison is based on experiments with these pumping devices at a field station in a village in central-east India. Our work identifies the major gaps in the study of large ram pumps, covering the hydraulic scaling conformance to creation of a unified platform for the investigation of such pumping devices with respect to operating parameters like head, flow, efficiency and, most importantly, size. The field tests of ram revealed that its non-dimensional performance parameters fit perfectly on the theoretical scaling curves. The investigations further showed that while rams had more efficiency (53–62%), they could not handle more than 40–50 l/s of discharge. In comparison, the turbine pumps, tested in laboratory conditions, were more compact for flows beyond 100 l/s, but they settled for overall efficiencies between 49% and 55%. The study recommends a limiting design flow line for rams to be 50 l/s because of the size-factor. It further finds that for absolute flows between 50 and 100 l/s within the low-head range of 3–5 meters, the design of geometrical shapes for turbine pumps could be a challenge for optimized efficiencies. The head-discharge-diameter (H-Q-D) chart developed here is a useful way of interpreting the technology with respect to boundary conditions and it creates a roadmap for future inventions in such renewable hydro-pumping devices. The paper makes a case for axial flow pumps as turbines. It concludes with a call for the propagation of research on such nature-friendly pumping technologies, where most (90–95%) of the water is returned to the stream, paving the way for a new era of sustainability.

Study of Parasitic Infection in Immunosuppressive Patients and its Association with the Socio-demographic Status

Introduction: In developing countries, immunosuppressive patients are at greater risk of parasitic infection which may cause morbidity and mortality. Socio-economic and environmental factors including lack of health hygiene in close contact with infected reservoir animal which plays an important role. Aim: To determine the prevalence of parasitic infections and their association with socio-demographic status. Materials and Methods: This was a cross-sectional study which was carried out at tertiary care hospital located in Central East India. Total 120 stool samples were collected from the immunosuppressive patients and were processed using direct wet mount preparation with saline and Lugol, formalin-ether concentration and Modified Ziehl-Neelsen stain. Different socio-demographic parameters were recorded. Statistical analysis was done using Graph Pad Prism version 8 Chi-square test. The p-value ≤0.05 was considered as statistically significant Results: Out of total 120 patients, 20 (16.7%) were found to be infected. Majority of the population were males (66.7%). Among the total positive samples, 75% (15) showed the presence of Protozoa in which 10 samples had Entamoeba histolytica. The presence of Helminths was found in 25% (5), in which three samples showed Ascaris lumbricoides and two had Taenia species (10%). Conclusion: The prevalence of parasitic infection among immunosuppressive patients in the present study was 16.7%. Entamoeba histolytica was the most commonly observed parasite. There was no significant association between prevalence of parasitic infections and socio-demographic data variables.

Mercury, arsenic, lead and cadmium in waters of the Singrauli coal mining and power plants industrial zone, Central East India.

The present investigation is an attempt to assess the contamination of heavy metals in the ground and surface water of the Singrauli industrial belt area. Pollution indices like heavy metal index (HPI), contamination index (CD) and heavy metal evaluation index (HEI) are used for the evaluation of heavy metal pollution (arsenic As, mercury Hg, cadmium Cd, and lead Pb). Contour maps are constructed to interpret metal spatial distribution. Further, the land-use/land-cover (LULC) maps for the year 2000, 2010 and 2016 are prepared using Landsat satellite data. A total of 48 water samples (Groundwater (27), Surface water (21)) are analysed for heavy metal concentration. Eighty-eight percent of groundwater and 90% of surface water samples are contaminated with Hg. Similarly, high concentrations of Pb and Cd were found in the samples. Surprisingly, all the water samples have As concentration above the WHO permissible limit of 10ppb. Further, 95% of the samples have an HPI value greater than 100 indicating high heavy metal contamination. CD value denotes contamination of 89% of the samples with heavy metals (As, Hg, Cd, Pb). Through spatial distribution, it can be interpreted that most of the contaminated samples lie near thermal power plants, ash ponds, and coal mines. LULC (land use/land cover) study shows a significant decrease in water bodies by (108km2), agricultural land by (54km2) and bare/fallow land by (51km2) from 2000 to 2016. During these 16years, there has been a fourfold increase in the overburden, a threefold increase in dumping yards, a 2.5 times increase in urban areas, and a twofold increase in mining areas. Both the environment and the water quality are deteriorating at an alarming rate. Such scientific investigations are relevant for risk management studies of potable water. The knowledge acquired from such assessment shall be considered with utmost priority by concerned authority considering degrading water quality in the study area. Hence, this study is applicable for designing action plans and control measures to reduce water resource pollution.

Pattern recognition techniques for evaluating the spatial impact of copper mining on surface waters

In this study, multivariate statistical approaches, namely hierarchical cluster analysis (CA) and principal component analysis (PCA), were employed to understand the impact of copper mining on surface waters located in Central-East India. The data set generated consisted of nine parameters, namely pH, dissolved oxygen (DO), alkalinity, total dissolved solids, copper, iron, manganese, zinc and fluoride, collected in forty sampling points covering all seasons. As delineated by CA, the entire data set for both the surface waters was bifurcated into groups, namely Banjar River inclusion of seepage points (BRISP) and Banjar River exclusion of seepage points (BRESP), Son River inclusion of seepage points (SRISP) and Son River exclusion of seepage points (SRESP). Four latent factors were identified, namely copper, iron, fluoride and manganese, explaining 84.7 % of variance for BRISP, 71.9 % of variance for BRESP, 66.7 % of variance for SRISP and 68 % of variance for SRESP. The extensive application of PCA on BRISP, BRESP, SRISP and SRESP reveals that the main stream of both the rivers remains unaffected by mining operations when seepage points were excluded. Additionally, iron content is considerably significant throughout the stream due to the geogenic sources and it is considered as a major factor for the depletion of DO level in the streams. This study reveals the level of contamination in the studied surface waters and the effectiveness of multivariate statistical techniques for evaluation and interpretation of complex data matrix in understanding the spatial variations and identification of pollution sources.

Risk assessment of extreme Indian summer monsoon precipitation on agro-ecosystem of northern and central-east India

Risk of extreme precipitation anomaly of Indian summer monsoon (ISM) on agro-ecosystems of Indo-Gangetic Plain (IGP) and central-east India regions has been assessed in the present study. Using monthly gridded precipitation data, standardized precipitation index (SPI) has been computed as the hazard component of the standard risk computation. The agro-ecosystems of IGP are exposed to higher risk due to extreme ISM precipitation anomaly than that of the central-east India. IGP being an irrigated region and central-east India being a rainfed region would be affected differentially due to the increasing negative anomaly in precipitation (i.e., drought risk) in the two regions. Overall the risk score and the prevalent agricultural practice suggest that the Central plateau and hill region in the rainfed region and the Upper Gangetic plain in the irrigated region are the most drought risk pone agroclimatic zones. Exceedance probability (EP) curve and the return period (RP) curve of drought risk quantification revealed that the Upper Gangetic plain of the IGP is conspicuously exposed to a higher drought risk unlike any other region. Increasing drought risk is coupled with increasing cloud cover in Upper Gangetic plain. Surface wind, temperature or the outgoing longwave radiation of this zone could not completely explain the cause of this risk. Changing role of average aerosol index (AAI) hinted to the presence of aerosol altered cloud micro-system in Upper Gangetic plain and may be one of the major reasons for increasing non-precipitating cloud in this zone and thus contributing to the drought risk even with increasing cloud cover trend.

Association between wood cooking fuel and maternal hypertension at delivery in central East India

Objective: Smoke from burning of biomass fuels has been linked with adverse pregnancy outcomes and hypertension among nonpregnant subjects; association with hypertension during pregnancy has not been well studied. We evaluated whether the use of wood cooking fuel increases the risk of maternal hypertension at delivery compared to gas which burns with less smoke. Methods: Information on fuel use and blood pressure was available for analysis from a cross-sectional survey of 1369 pregnant women recruited at delivery in India. Results: Compared to gas users, women using wood as fuel had on average lower mean arterial pressure (adjusted effect size − 2.0 mmHg; 95% CI: −3.77, −0.31) and diastolic blood pressure (adjusted effect size −1.96 mmHg; 95% CI: −3.60, −0.30) at delivery. Risk of hypertension (systolic >139 mmHg or diastolic >89 mmHg) was 14.6% for wood users compared to 19.6% for gas users although this did not reach significance after adjustment, using propensity score techniques, for factors that make wood and gas users distinct (adjusted prevalence ratio 0.76; 95% CI: 0.49, 1.17). Conclusions: Combustion products from the burning of biomass fuels are similar to those released with tobacco smoking, which has been linked with a reduced risk for preeclampsia. The direction of our findings suggests the possibility of a similar effect for biomass cook smoke. Whether clean cooking interventions being promoted by international advocacy organizations will impact hypertension in pregnancy warrants further analysis as hypertension remains a leading cause of maternal death worldwide and cooking with biomass fuels is widespread.

Knockdown resistance (kdr) mutations in Indian Anopheles culicifacies populations.

BackgroundAnopheles culicifacies s.l. is one of the primary vectors of malaria in India responsible for the highest number of malaria cases. This vector is resistant to DDT in most parts of the country with indication of emerging resistance to pyrethroids. Since knockdown resistance (kdr) is known to confer cross-resistance between DDT and pyrethroids owing to a common target site of action, knowledge of prevalence of knockdown resistance (kdr) alleles is important from insecticide resistance management point of view.MethodsNine populations of An. culicifacies belonging to five states of India, representing northern, western and central-east India, were screened for the presence of two alternative kdr mutations L1014F and L1014S using PCR-based assays. Dead and alive mosquitoes, following WHO standard insecticide susceptibility test against deltamethrin and DDT, were tested for allelic association.ResultsL1014F mutation was recorded in all populations studied except from Haryana and Rajasthan states in northern India, with low frequencies ranging between 0.012 and 0.076; whereas presence of L1014S mutation was recorded in five populations only belonging to central-east India, with allelic frequencies ranging between 0.010 and 0.046. Both the kdr mutant alleles were found mostly in heterozygous condition without deviating from Hardy-Weinberg equilibrium. Both mutations showed protection against deltamethrin whereas only L1014S mutation showed protection against DDT when tested using additive model.ConclusionsThe two L1014-kdr mutations, L1014F and L1014S, co-occurred in five populations belonging to Chhattisgarh and Odisha states of India whereas L1014F was present in all populations studied except populations from northern states. Both kdr mutations were found with very low allelic frequencies mostly in heterozygous condition and exhibited protection against deltamethrin.

Moisture variability over the Indo-Pacific region and its influence on the Indian summer monsoon rainfall

The Indo-Pacific Ocean (i.e. region between 30°E and 150°E) has been experiencing a warming since the 1950s. At the same time, the large-scale summer monsoon rainfall over India and the moisture over the East Africa/Arabian Sea are both decreasing. In this study, we intend to investigate how the decrease of moisture over the East Africa/Arabian Sea is related to the Indo-Pacific Ocean warming and how this could affect the variability of the Indian summer monsoon rainfall. We performed the analysis for the period 1951–2012 based on observed precipitation, sea surface temperature and atmospheric reanalysis products and we verified the robustness of the result by comparing different datasets. The decreasing trend of moisture over the East Africa/Arabian Sea coincides with an increasing trend of moisture over the western Pacific region. This is accompanied by the strengthening (weakening) of the upward motion over the western Pacific (East Africa/Arabian Sea) that, consequently, contributes to modulate the western Pacific-Indian Ocean Walker circulation. At the same time, the low-level westerlies are weakening over the peninsular India, thus contributing to the reduction of moisture transport towards India. Therefore, rainfall has decreased over the Western Ghats and central-east India. Contrary to previous decades, since 2003 moisture over the East Africa/Arabian Sea started to increase and this is accompanied by the strengthening of convection due to increased warming of sea surface temperature over the western Arabian Sea. Despite this moisture increase over the Arabian Sea, we found that moisture transport is still weakening over the Indian landmass in the very recent decade and this has been contributing to the decreased precipitation over the northeast India and southern part of the Western Ghats.

Impact of biomass fuels on pregnancy outcomes in central East India

BackgroundSmoke from biomass burning has been linked to reduced birth weight; association with other birth outcomes is poorly understood. Our objective was to evaluate effects of exposure to biomass smoke on birth weight, preterm birth and stillbirth.MethodsInformation on household cooking fuel was available for secondary analysis from two cohorts of pregnant women enrolled at delivery in India (n = 1744). Birth weight was measured and the modified Ballard performed to assess gestational age. Linear and logistic regression models were used to explore associations between fuel and birth outcomes. Effect sizes were adjusted in multivariate models for socio-demographic characteristics using propensity score techniques and for medical/obstetric covariates.ResultsCompared to women who use gas (n = 265), women cooking with wood (n = 1306) delivered infants that were on average 112 grams lighter (95% CI -170.1, -54.6) and more likely to be preterm (OR 3.11, 95% CI 2.12, 4.59). Stillbirths were also more common in the wood group (4% versus 0%, p < 0.001). In adjusted models, the association between wood use and birth weight was no longer significant (14 g reduction; 95% CI -93, 66); however, the increased odds for preterm birth persisted (aOR 2.29; 95% CI 1.24, 4.21). Wood fuel use did not increase the risk of delivering either a low birth weight or small for gestational age infant.ConclusionsThe association between wood fuel use and reduced birth weight was insignificant in multivariate models using propensity score techniques to account for socio-demographic differences. In contrast, we demonstrated a persistent adverse impact of wood fuel use on preterm delivery. If prematurity is confirmed as a consequence of antenatal exposure to household air pollution, perinatal morbidity and mortality from household air pollution may be higher than previously appreciated.

Arsenic contamination and its causative factors in parts of Chhattisgarh, Central East India

This paper reports the present status of ground water arsenic contamination in the parts of Ambagarh Chowki block in District Rajnandgaon, of Chhattisgarh State. This location is the first arsenic contaminated location reported outside Bengal Delta Plain. The analysis of arsenic contamination measured during year 2008 to 2009 is compared with previously reported synoptic sampling results. This study was necessitated to know and account for the extent of arsenic spread in the groundwater of the area. In the area survey, many new arsenic contaminated locations have been identified in these areas, which were not reported earlier. The water samples were collected from 46 sites of Rajnandgaon District and 78% of the studied locations are contaminated by the presence of arsenic in the range of 2–4,570 µg/L. It was observed that the arsenic levels are fluctuating and appear to be geogenic. Overall the results indicate an urgent need for scientific management of arsenic contamination issues.

Arsenic contamination in central-east India: new lessons for environmental health

This paper reports high levels and variability in the arsenic (As) levels at locations identified as one of the highest As-contaminated locations in the world. The high levels and variability in As levels were established by a strict monitoring protocol and the minimum possible time lag between the sampling and analysis. Special sampling arrangements were created at the central-east Indian location to monitor regularly the various water quality parameters at four specific locations. Out of the four monitored locations the locations 1–3 were found contaminated on more than 90% and the public water supply source (location 4) was found contaminated on more than 38% sampling episodes as per Indian standards. If the WHO standards for As (max. 0.01 mg/L) are considered then all the inhabitants were supplied with unacceptable drinking water on ∼93% of the sampled days during the sampling period. The paper identifies many complexities in the management of As-contamination and the perils of low level contamination in the As-endemic areas.

Preservation Artifacts and Loss Pattern of Arsenic: A Case Study from Highly Contaminated Location in Central-East India

Arsenic is the focus of public attention because of its wider prevalence and toxicity. Proper sampling is important in characterizing toxic water contaminants in the groundwater. The present paper studies aspects of sampling, preservation artifacts, analytical issues etc. in a natural arsenic contaminated groundwater. The samples were collected from arsenic contaminated groundwater at three locations of village Kaudikasa in Rajnandgaon (Chhattisgarh). The standard method of sampling and preservation of arsenic was examined. The permitted sample holding time in this state is 180 days which has been found to be unrealistic on examination. The communication also compares the loss pattern of arsenic in unpreserved samples with samples preserved and kept at 4?C. It was found that about As losses during hold- ing after preservation were about 0% in one day, 35% in seven day, 70% in fifteen day, and 65% in thirty days time. Hence, the present recommended method of preservation leads to huge under reporting of As in natural samples. If the pattern of losses observed at the present location exists at other locations then the actual As levels could be much higher than the reported ones.

Burden of malaria in pregnancy in Jharkhand State, India

BackgroundPast studies in India included only symptomatic pregnant women and thus may have overestimated the proportion of women with malaria. Given the large population at risk, a cross sectional study was conducted in order to better define the burden of malaria in pregnancy in Jharkhand, a malaria-endemic state in central-east India.MethodsCross-sectional surveys at antenatal clinics and delivery units were performed over a 12-month period at two district hospitals in urban and semi-urban areas, and a rural mission hospital. Malaria was diagnosed by Giemsa-stained blood smear and/or rapid diagnostic test using peripheral or placental blood.Results2,386 pregnant women were enrolled at the antenatal clinics and 718 at the delivery units. 1.8% (43/2382) of the antenatal clinic cohort had a positive diagnostic test for malaria (53.5% Plasmodium falciparum, 37.2% Plasmodium vivax, and 9.3% mixed infections). Peripheral parasitaemia was more common in pregnant women attending antenatal clinics in rural sites (adjusted relative risk [aRR] 4.31, 95%CI 1.84-10.11) and in those who were younger than 20 years (aRR 2.68, 95%CI 1.03-6.98). Among delivery unit participants, 1.7% (12/717) had peripheral parasitaemia and 2.4% (17/712) had placental parasitaemia. Women attending delivery units were more likely to be parasitaemic if they were in their first or second pregnancy (aRR 3.17, 95%CI 1.32-7.61), had fever in the last week (aRR 5.34, 95%CI 2.89-9.90), or had rural residence (aRR 3.10, 95%CI 1.66-5.79). Malaria control measures including indoor residual spraying (IRS) and untreated bed nets were common, whereas insecticide-treated bed nets (ITN) and malaria chemoprophylaxis were rarely used.ConclusionThe prevalence of malaria among pregnant women was relatively low. However, given the large at-risk population in this malaria-endemic region of India, there is a need to enhance ITN availability and use for prevention of malaria in pregnancy, and to improve case management of symptomatic pregnant women.

Toxic mine drainage from Asia’s biggest copper mine at Malanjkhand, India

This paper has studied the environmental deterioration due to copper mining in Malanjkhand at Central-east India. No data is available on environmental degradation at the studied site although geological aspects are well studied. Mine drainage from the mines is definitively toxic. The site is also undergoing various stages of acid mine drainage (AMD) particularly from the heap leaching sites and the tailing area. AMD impacted water steam and sediment were also analysed. Results show substantial level of contamination of almost all segments of environment. Presence of elevated level of other heavy metal viz. Au, Ag, Pb, Cr, Cd, Fe, Cu and base metals like Na, K in AMD impacted water and sediments is due to metal leaching effect of AMD. Bio monitoring with the help of benthic macro invertebrates and metal accumulation in plants was also carried to know the impact of the toxic drainage. Results prove a very significant impact on the environmental health.

Arsenic contamination in the Kanker district of central-east India: geology and health effects

This paper identifies newer areas of arsenic contamination in the District Kanker, which adjoins the District Rajnandgaon where high contamination has been reported earlier. A correlation with the mobile phase episodes of arsenic contamination has been identified, which further hinges on the complex geology of the area. Arsenic concentrations in both surface and groundwater, aquatic organisms (snail and water weeds) soil and vegetation of Kanker district and its adjoining area have been reported here. The region has been found to contain an elevated level of arsenic. All segments of the ecoysystem are contaminated with arsenic at varying degrees. The levels of arsenic vary constantly depending on the season and location. An analysis of groundwater from 89 locations in the Kanker district has shown high values of arsenic, iron and manganese (mean: 144, 914 and 371 microg L(-1), respectively). The surface water of the region shows elevated levels of arsenic, which is influenced by the geological mineralised zonation. The most prevalent species in the groundwater is As(III), whereas the surface water of the rivers shows a significant contamination with the As(V) species. The analysis shows a bio-concentration of the toxic metals arsenic, nickel, copper and chromium. Higher arsenic concentrations (groundwater concentrations greater than 50 microg L(-1)) are associated with sedimentary deposits derived from volcanic rocks, hence mineral leaching appears to be the source of arsenic contamination. Higher levels of arsenic and manganese in the Kanker district have been found to cause impacts on the flora and fauna. A case study of episodic arsenical diarrhoea is presented.

Arsenic contamination of the environment. A new perspective from central-east India : Pandey, P. K. et al. Environment International, 2002, 28, (4), 235–245

Arsenic contamination of the environment. A new perspective from central-east India : Pandey, P. K. et al. Environment International, 2002, 28, (4), 235–245

Arsenic contamination of the environment: A new perspective from central-east India

This paper reports a regional contamination of the environment in central-east India that does not share geology or boundary with the Bengal Delta Plain. About 30,000 people residing in 30 villages and towns are directly exposed to arsenic and more than 200,000 people are “at risk.” Complete geographical extent of this contamination is being established, and this newly reported contaminated area could be quite large. This paper further reports that the mechanisms involved in arsenic mobilisation are complex and the two theories of arsenic mobilisation, i.e., pyrite oxidation and oxyhydroxides reduction, do not fully explain the high levels of arsenic contamination. This paper also proposes the “oxidation–reduction theory” for arsenic mobilisation where the arsenic originates from the arsenopyrite oxidation and the arsenic thus mobilised forms the minerals and gets reduced underground in favourable Eh conditions. The stoppage of water withdrawal from the contaminated sources did not result in lowering of arsenic levels as expected according to the heavy groundwater extraction theory (pyrite oxidation theory). Cases of arsenicosis in the region are on the rise and the switchover to less contaminated water has not reversed the arsenicosis progression in the affected persons even after 2 years. Surface water of the rivers is also being contaminated because of the probable dislocation of contaminated groundwater due to the heavy rains in monsoon season, which indicates that the river water could be a major carrier of arsenic in dissolved or adsorbed forms that may be a cause of contamination of the delta plains.