Effect of cooking method and rice type on arsenic concentration in cooked rice and the estimation of arsenic dietary intake in a rural village in West Bengal,India

Arsenic (As) contamination of rice plants can result in high total As concentrations (t-As) in cooked rice, especially if As-contaminated water is used for cooking. This study examines two variables: (1) the cooking method (water volume and inclusion of a washing step); and (2) the rice type (atab and boiled). Cooking water and raw atab and boiled rice contained 40 μg As l^?1 and 185 and 315 μg As kg^?1, respectively. In general, all cooking methods increased t-As from the levels in raw rice; however, raw boiled rice decreased its t-As by 12.7% when cooked by the traditional method, but increased by 15.9% or 23.5% when cooked by the intermediate or contemporary methods, respectively. Based on the best possible scenario (the traditional cooking method leading to the lowest level of contamination, and the atab rice type with the lowest As content), t-As daily intake was estimated to be 328 μg, which was twice the tolerable daily intake of 150 μg.     

Contribution of water and cooked rice to an estimation of the dietary intake of inorganic arsenic in a rural village of West Bengal,India

Arsenic contamination of rice plants by arsenic-polluted irrigation groundwater could result in high arsenic concentrations in cooked rice. The main objective of the study was to estimate the total and inorganic arsenic intakes in a rural population of West Bengal, India, through both drinking water and cooked rice. Simulated cooking of rice with different levels of arsenic species in the cooking water was carried out. The presence of arsenic in the cooking water was provided by four arsenic species (arsenite, arsenate, methylarsonate or dimethylarsinate) and at three total arsenic concentrations (50,?250 or 500?µg?l^?1). The results show that the arsenic concentration in cooked rice is always higher than that in raw rice and range from 227 to 1642?µg?kg^?1. The cooking process did not change the arsenic speciation in rice. Cooked rice contributed a mean of 41% to the daily intake of inorganic arsenic. The daily inorganic arsenic intakes for water plus rice were 229, 1024 and 2000?µg?day^?1 for initial arsenic concentrations in the cooking water of 50, 250 and 500?µg?arsenic?l^?1, respectively, compared with the tolerable daily intake which is 150?µg?day^?1.     

Contribution of water and cooked rice to an estimation of the dietary intake of inorganic arsenic in a rural village of West Bengal, India

Arsenic contamination of rice plants by arsenic-polluted irrigation groundwater could result in high arsenic concentrations in cooked rice. The main objective of the study was to estimate the total and inorganic arsenic intakes in a rural population of West Bengal, India, through both drinking water and cooked rice. Simulated cooking of rice with different levels of arsenic species in the cooking water was carried out. The presence of arsenic in the cooking water was provided by four arsenic species (arsenite, arsenate, methylarsonate or dimethylarsinate) and at three total arsenic concentrations (50, 250 or 500 µg l^-1). The results show that the arsenic concentration in cooked rice is always higher than that in raw rice and range from 227 to 1642 µg kg^-1. The cooking process did not change the arsenic speciation in rice. Cooked rice contributed a mean of 41% to the daily intake of inorganic arsenic. The daily inorganic arsenic intakes for water plus rice were 229, 1024 and 2000 µg day^-1 for initial arsenic concentrations in the cooking water of 50, 250 and 500 µg arsenic l^-1, respectively, compared with the tolerable daily intake which is 150 µg day^-1.     

Comparative Study of Antioxidant Activity of the Food Flowers of West Bengal,India

In India, many flowers are consumed as food. During the present study, 37 flowers have been analyzed for their 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity and total antioxidant capacity. The flowers were found to have different levels of antioxidant properties in the systems tested. On the basis of the activity and availability, a few flowers were further studied for hydroxyl radical scavenging activity, superoxide radical scavenging activity, lipid peroxidation prevention, and DNA damage prevention properties. The correlations suggest that the total phenol contents of the flowers were responsible for the antioxidant properties of the aqueous extracts. The unweighted-pair group average dendrogram showing interrelationships between the investigated species grouped them into two high level clusters based on activity.     

Arsenic contamination in sesame and possible mitigation through organic interventions in the lower Gangetic Plain of West Bengal, India

BACKGROUND: The widespread geogenic arsenic contamination of groundwater in the Gangetic Delta of West Bengal, leading to toxicities through the food chain—principally through irrigated rice—drew due attention from researchers. Oilseeds such as sesame might be a remunerative alternative to rice and can be grown with small quantities of contaminated groundwater. RESULTS: The present study was conducted to explore the efficiency of organic matter in reducing arsenic accumulation in sesame. Accumulation of total arsenic in sesame seed and available arsenic in post‐harvest soils varied from 0.08 to 0.58 mg kg^?1 and from 3.87 to 8.89 kg ha^?1, respectively. The organic manures added as soil amendment significantly reduced the accumulation (concentration) of arsenic in sesame seed to a maximum extent of 65.5% (vermicompost), 50% (phosphocompost), 42% (mustard cake) and 40% (farmyard manure (FYM)) compared with the control counterpart. The risk associated with dietary exposure to arsenic‐contaminated sesame oil reached a value of 15.55% of provisional tolerable weekly intake for arsenic at the maximum accumulation of arsenic in sesame oil. CONCLUSION: Substantial accumulation of arsenic in the soil–plant system was found. Risks of exposure to arsenic‐contaminated oil remained considerably high. Irrigation through surface water and organic amendments both significantly reduced arsenic accumulation in sesame. Copyright © 2011 Society of Chemical Industry     

Undernutrition among adult Dhimals of Naxalbari, West Bengal: comparison with other tribes of eastern India

BACKGROUND: The tribes of India comprise approximately 8% of the total population of the country, which probably has the largest number of tribal communities in the world. In general, the tribal populations are among the most underprivileged and undernourished people in India. OBJECTIVES: To determine the anthropometric characteristics and prevalence of undernutrition, based on body mass index (BMI), of adult Dhimals, a tribal population of Naxalbari, West Bengal, India, and to compare these results with those from four other tribes of Eastern India: the Bathudis, Kora Mudis, Santals, and Savars. METHODS: A total of 305 adult (18 years or older) Dhimals (159 men and 146 women) from three villages (Maniram, Hatighisa, and Buraganj) in the Mallabari area of Naxalbari were studied. These villages are located 5 km from Siliguri town, which is approximately 580 km from Kolkata, the provincial capital of West Bengal. Anthropometric measurements included height and weight. BMI was calculated by the standard equation. Undernutrition was evaluated according to World Health Organization (WHO) cutoff points. RESULTS: The overall prevalence of undernutrition (BMI < 18.5) was very high (36.4%). The prevalence was significantly higher in women than in men (46.4% vs. 27.0%; chi2 = 12.54; p < .001; odds ratio, 2.35). According to the WHO criterion, the prevalence of undernutrition was high and the situation was serious in men. Among women, the prevalence of undernutrition was very high and the situation was critical. However, in general, compared with other tribal people of eastern India except the Santals, adult Dhimals had better anthropometric and nutritional profiles. CONCLUSIONS: This study provides evidence that although the anthropometric and nutritional profiles of adult Dhimals are better than those of some of the other tribal populations of eastern India, immediate appropriate nutritional intervention programs are needed for implementation among this ethnic group.     

Codeposition of organic carbon and arsenic in Bengal Delta aquifers

We present data showing that arsenic (As) was codeposited with organic carbon (OC) in Bengal Delta sediments as As and OC concentrations are highly (p < 0.001) positively correlated in core profiles collected from widely dispersed geographical sites with different sedimentary depositional histories. Analysis of modern day depositional environments revealed that the As-OC correlations observed in cores are due to As retention and high OC inputs in vegetated zones of the deltaic environment. We hypothesize that elevated concentrations of As occur in vegetated wetland sediments due to concentration and retention of arsenate in aerated root zones and animal burrows where copious iron(III) oxides are deposited. On burial of the sediment, degradation of organic carbon from plant and animal biomass detritus provides the reducing conditions to dissolve iron(III) oxides and release arsenite into the porewater. As tubewell abstracted aquifer water is an invaluable resource on which much of Southeast Asia is now dependent, this increased understanding of the processes responsible for As buildup and release will identify, through knowledge of the palaeosedimentary environment, which sediments are at most risk of having high arsenic concentrations in porewater. Our data allow the development of a new unifying hypothesis of how As is mobilized into groundwaters in river flood plains and deltas of Southeast Asia, namely that in these highly biologically productive environments, As and OC are codeposited, and the codeposited OC drives As release from the sediments.     

Food insecurity in urban poor households in Mumbai, India

India ranks 66th of 88 countries in the Global Hunger Index and has a quarter of the world??s hungry. Food security status of 377 million inhabitants of India??s urban areas, of which one-fourth live in extreme poverty, is poorly documented. The purpose of this study was to determine (a) the extent of food insecurity among households in urban slums, (b) to quantitatively assess their subjective experiences related to food insecurity and (c) to identify sub-groups among the urban poor that are vulnerable to food insecurity. A cross-sectional, interviewer-administered survey of adult female respondents from 283 households, selected using two-stage cluster sampling, was conducted in slums across three municipal wards in the city of Mumbai. Food insecurity, as measured by the Household Food Insecurity Access Scale (HFIAS), was found in a large number of households in the urban slums of Mumbai; 59.7?% (n?=?169) households were categorized as severely food-insecure, 16.6?% (n?=?47) as mildly to moderately food-insecure, and 23.7?% (n?=?67) as food-secure. Further analysis revealed that severe food insecurity was significantly associated with lower monthly household income and other socioeconomic status measures such as lower household monthly per capita income, lower rank in the standard of living index (SLI) and less monthly per capita expense on food items. Households where the woman was the primary income-earner and contributed the largest share to the monthly household income, and was older, less educated, with less media use or access were more likely to experience severe food insecurity. Although corrective steps at the household level such as livelihood security schemes and income generation programs are necessary, they will not be sufficient to eliminate this problem; state intervention is required in order to assure food security for the urban poor. The Government of India has drafted a Food Security Bill; but the criteria for determining which households are vulnerable and deserving are still being debated. The findings of this study highlight the urgency of corrective action and also provide pointers for the identification of vulnerable or priority sub-groups. Food security policies and programs have to be implemented immediately and effectively in order to ensure that subsidies and food items are allocated to the households of the vulnerable urban poor.     

Consumption of brown rice: a potential pathway for arsenic exposure in rural Bengal

This study assesses the arsenic (As) accumulation in different varieties of rice grain, that people in rural Bengal mostly prefer for daily consumption, to estimate the potential risk of dietary As exposure through rice intake. The rice samples have been classified according to their average length (L) and L to breadth (B) ratio into four categories, such as short-bold (SB), medium-slender (MS), long-slender (LS), and extra-long slender (ELS). The brown colored rice samples fall into the SB, MS, or LS categories; while all Indian Basmati (white colored) are classified as ELS. The study indicates that the average accumulation of As in rice grain increases with a decrease of grain size (ELS: 0.04; LS: 0.10; MS: 0.16; and SB: 0.33 mg kg(-1)), however people living in the rural villages mostly prefer brown colored SB type of rice because of its lower cost. For the participants consuming SB type of brown rice, the total daily intake of inorganic As (TDI-iAs) in 29% of the cases exceeds the previous WHO recommended provisional tolerable daily intake value (2.1 μg day(-1) kg(-1) BW), and in more than 90% of cases, the As content in the drinking water equivalent to the inorganic As intake from rice consumption (C(W,eqv)) exceeds the WHO drinking water guideline of 10 μg L(-1). This study further demonstrates that participants in age groups 18-30 and 51-65 yrs are the most vulnerable to the potential health threat of dietary As exposure compared to participants of age group 31-50 yrs, because of higher amounts of brown rice consumption patterns and lower BMI.     

Occurrence and removal of chloro-s-triazines in water treatment plants

Atrazine, simazine, and propazine and their major chlorinated degradates (deethylatrazine, deisopropylatrazine, and didealkylatrazine) are considered as a group to be endocrine-disrupting chemicals by the U.S. Environmental Protection Agency. On this basis, regulatory action levels are currently under consideration for the total chloro-s-triazine (TCT) levels in drinking waters. To assess the concentrations of each of these species in drinking water and their treatability in conventional water treatment, a comprehensive, full-scale studywas conducted that included frequent monitoring at 33 and 47 water utilities during 2003 and 2004, respectively. Approximately 900 paired raw and treated water samples were analyzed using a gas chromatography/mass spectrometry method with preconcentration using a mixed-mode, solid-phase extraction that allowed quantitation of each species including didealkylatrazine. The results showed that atrazine concentrations were generally well within the 3 microg/L maximum contaminant level (MCL) and that simazine and propazine concentrations were generally negligible. Ninety-fifth-percentile values for the ratio of TCT/atrazine were 4.8 and 4.7, respectively. Effectiveness of conventional treatment technologies, including carbon, was observed to vary significantly. Concerns that didealkyatrazine concentrations may be high and significantly elevate the TCT appear to be unfounded. In general, the results suggest that potential treatment requirements for TCT are not likely to be any more difficult for utilities to meet than the current requirements for atrazine.     

Preparation and evaluation of GAC-based iron-containing adsorbents for arsenic removal

Granular activated carbon-based, iron-containing adsorbents (As-GAC) were developed for effective removal of arsenic from drinking water. Granular activated carbon (GAC) was used primarily as a supporting medium for ferric iron that was impregnated by ferrous chloride (FeCl2) treatment, followed by chemical oxidation. Sodium hypochlorite (NaClO) was the most effective oxidant, and carbons produced from steam activation of lignite were most suitable for iron impregnation and arsenic removal. Two As-GAC materials prepared by FeCl2 treatment (0.025 -0.40 M) of Dacro 20 x 50 and Dacro 20 x 40LI resulted in a maximum impregnated iron of 7.89% for Dacro 20 x 50 and 7.65% for Dacro 20 x 40Ll. Nitrogen adsorption-desorption analyses showed the BET specific surface area, total pore volume, porosity, and average mesoporous diameter all decreased with iron impregnation, indicating that some micropores were blocked. SEM studies with associated EDS indicated that the distribution of iron in the adsorbents was mainly on the edge of As-GAC in the low iron content (approximately 1% Fe) sample but extended to the center at the higher iron content (approximately 6% Fe). When the iron content was > approximately 7%, an iron ring formed at the edge of the GAC particles. No difference in X-ray diffraction patterns was observed between untreated GAC and the one with 4.12% iron, suggesting that the impregnated iron was predominantly in amorphous form. As-GAC could remove arsenic most efficiently when the iron content was approximately 6%; further increases of iron decreased arsenic adsorption. The removal of arsenate occurred in a wide range of pH as examined from 4.4 to 11, but efficiency was decreased when pH was higher than 9.0. The presence of phosphate and silicate could significantly decrease arsenate removal at pH > 8.5, while the effects of sulfate, chloride, and fluoride were minimal. Column studies showed that both As(V) and As(III) could be removed to below 10 microg/L within 6000 empty bed volume when the groundwater containing approximately 50 microg/L of arsenic was treated.     

燃煤电厂脱硫脱硝除尘技术应用研究

随着我国工业化进程的不断推进以及居民生活水平的不断提高,化石燃料使用过程逐渐引发的多种环境污染问题也越来越严重。在国家倡议低碳经济、可持续发展战略的背景之下,燃煤电厂可通过脱硫脱硝除尘技术有效降低污染,从而实现低碳经济。     

Solar oxidation and removal of arsenic at circumneutral pH in iron containing waters

An estimated 30-50 million people in Bangladesh consume groundwater with arsenic contents far above accepted limits. A better understanding of arsenic redox kinetics and simple water treatment procedures are urgently needed. We have studied thermal and photochemical As(III) oxidation in the laboratory, on a time scale of hours, in water containing 500 micrograms/L As(III), 0.06-5 mg/L Fe(II,III), and 4-6 mM bicarbonate at pH 6.5-8.0. As(V) was measured colorimetrically, and As(III) and As(tot) were measured by As(III)/As(tot)-specific hydride-generation AAS. Dissolved oxygen and micromolar hydrogen peroxide did not oxidize As(III) on a time scale of hours. As(III) was partly oxidized in the dark by addition of Fe(II) to aerated water, presumably by reactive intermediates formed in the reduction of oxygen by Fe(II). In solutions containing 0.06-5 mg/L Fe(II,III), over 90% of As(III) could be oxidized photochemically within 2-3 h by illumination with 90 W/m2 UV-A light. Citrate, by forming Fe(III) citrate complexes that are photolyzed with high quantum yields, strongly accelerated As(III) oxidation. The photoproduct of citrate (3-oxoglutaric acid) induced rapid flocculation and precipitation of Fe(III). In laboratory tests, 80-90% of total arsenic was removed after addition of 50 microM citrate or 100-200 microL (4-8 drops) of lemon juice/L, illumination for 2-3 h, and precipitation. The same procedure was able to remove 45-78% of total arsenic in first field trials in Bangladesh.     

Selenium and arsenic speciation in fly ash from full-scale coal-burning utility plants

X-ray absorption fine structure spectroscopy has been used to determine directly the oxidation states and speciation of selenium and arsenic in 10 fly ash samples collected from full-scale utility plants. Such information is needed to assess the health risk posed by these elements in fly ash and to understand their behavior during combustion and in fly ash disposal options, such as sequestration in tailings ponds. Selenium is found predominantly as Se(IV) in selenite (SeO3(2-)) species, whereas arsenic is found predominantly as As(V) in arsenate (AsO4(3-)) species. Two distinct types of selenite and arsenate spectra were observed depending upon whether the fly ash was derived from eastern U.S. bituminous (Fe-rich) coals or from western subbituminous or lignite (Ca-rich) coals. Similar spectral details were observed for both arsenic and selenium in the two different types of fly ash, suggesting that the postcombustion behavior and capture of both of these elements are likely controlled by the same dominant element or phase in each type of fly ash.     

Difference of toxicity and accumulation of methylated and inorganic arsenic in arsenic-hyperaccumulating and -hypertolerant plants

The arsenic (As) hyperaccumulators, Pteris vittata and Pteris cretica and an As-tolerant plant Boehmeria nivea, were selected to compare the toxicity, uptake, and transportation of inorganic arsenate (As(V)) and its methylated counterpart dimethylarsinic acid (DMA). The XANES method was used to elucidate the effect of As species transformation on As toxicity and accumulation characteristics. Significantly higher toxicity and lower accumulation of DMAthan inorganic As(V) was shown in the As hyperaccumulators and the As-tolerant plant. Reduction of As(V) was commonly found in the plants. Arsenic complexation with thiols, which have less mobility in plants and usually occur in As-tolerant plants, was also found in rhizoids of P. cretica. Plants with greater ability to form As-thiolate have lower ability for upward transport of As. Demethylation of DMA occurred in the three plants. The DMA component decreased from the rhizoids to the fronds in both hyperaccumulators, while this tendency is reverse in B. nivea.     

Determination of total arsenic, inorganic and organic arsenic species in wine

Forty-five wine samples from the south of Spain of different alcoholic strength were analysed for total arsenic and its inorganic [As(III), As(V)] and organic (monomethylarsonic acid [MMAA], dimethylarsinic acid [DMAA]) species. The As levels of the wine samples ranged from 2.1 to 14.6 µg l^-1. The possible effect of the alcoholic fermentation process on the levels of the total arsenic and arsenical species was studied. The average total arsenic levels for the different samples were very similar, without significant differences between all types of wines. In table wines and sherry, the percentages of total inorganic arsenic were 18.6 and 15.6%, with DMAA or MMAA being the predominant species, respectively. In most samples, DMAA was the most abundant species, but the total inorganic aresenic fraction was considerable, representing 25.4% of the total concentration of the element. The estimated daily intakes of total arsenic and total inorganic arsenic for average Spanish consumers were 0.78 and 0.15 µg/person day^-1, respectively. The results suggest that the consumption of these types of wines makes no significant contribution to the total and inorganic arsenic intake for normal drinkers. However, wine consumption contributes a higher arsenic intake than through consumption of beers and sherry brandies.     

Effects of seed rate,nitrogen level and leaf age on the yield of extracted protein from five different crops in West Bengal

The yield of leaf protein from five different crops grown at different seed rates and nitrogen levels was studied. Bajra (Pennisetum typhoideum Rich.) and mustard (Brassica nigra Koch) gave large protein yields. Harvesting just before the initiation of flowering produced the highest yield except with hybrid Napier (P. typhoideum x P. purpureum) and turnip (Brassica rapa L.). With the latter, maximum yield was obtained 45–52 days after sowing, and with the former 62 days. Seed rates of 120–150 kg/ha (4–5 times normal) were used with bajra and ragi (Eleusine coracana Gaertn), 30 kg/ha with mustard and 8 kg/ha with turnip. The yield of extracted protein was not increased by giving mustard more than 60, ragi more than 160 and bajra more than 240 kg N/ha. The N level for maximum response was not reached with turnip and hybrid Napier. More of the leaf protein was extracted from mustard and turnip than from the other species; mustard and turnip also gave the largest yields of protein (7.6 and 5.7 kg/ha/day respectively).