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Arsenic articles - Fall 2011 and Winter 2012

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  • Laurel Schaider
    Apologies that it s been so long since the last summary of arsenic articles.  I m aiming to get back to monthly updates. -Laurel ... List of Topics: 1. Health
    Message 1 of 1 , Mar 20, 2012
      Apologies that it's been so long since the last summary of arsenic articles.  I'm aiming to get back to monthly updates.


      List of Topics:
      1. Health Effects and Exposure
      2. Distribution/ Extent of Affected Areas
      3. Geochemistry
      4. Water Testing, Water Treatment and Alternative Supplies
      5. Agriculture and Food Products
      6. Social aspects



      Long-Term Impact of
      Arsenic in Drinking Water on Bladder Cancer Health Care and Mortality Rates 20
      Years After End of Exposure. 2012. MI Fernandez, JF Lopez, B Vivaldi, F
      Coz. J. Urology. 187(3): 856-861.

      PURPOSE: In this study we assessed bladder cancer health
      care and mortality trends in recent decades in a well studied arsenic exposed
      area in Northern Chile.
      MATERIALS AND METHODS: Arsenic levels in the affected region
      were obtained for the last 60 years, and correlated with bladder cancer
      hospital discharge and mortality rates in recent decades.
      RESULTS: Bladder cancer hospital discharge rates were
      significantly higher in the affected region (peak RR 3.6, 95% CI 3.0-4.7).
      Mortality rates for bladder cancer showed a trend of increase during the period
      analyzed, reaching peak mortality rates of 28.4 per 100,000 for men and 18.7
      per 100,000 for women in the last 10 years. Poisson regression models showed an
      increased mortality risk in the studied region compared to the rest of the
      country until the present for men (IRR 5.3, 95% CI 4.8-5.8) and women (IRR 7.8,
      95% CI 7.0-8.7). Mean age at cancer specific death was significantly lower in
      the exposed region (69.6 years, 95% CI 68.4-70.7 vs 73.7 years, 95% CI
      73.3-74.2, p <0.01).
      CONCLUSIONS: Exposure to arsenic is related to a significant
      need for bladder cancer health care and to high mortality rates even 20 years
      after having controlled arsenic levels in drinking water. Affected individuals
      should be aware of the significant impact of this ecological factor. Further
      research is required to identify strategies for the management of bladder
      cancer in arsenic exposed populations.


      What is the best
      biomarker to assess arsenic exposure via drinking water? 2012. N Marchiset-Ferlay, C Savanovitch, MP
      Sauvant-Rochat. Environ. Int.  39(1): 150-171.

      Arsenic (As) is a ubiquitous element. The current WHO
      guideline for As in drinking water is 10 mu g/L Furthermore, about 130 million
      people have only access to drinking water containing more than 10 gAs/L.
      Although numerous studies have shown the related adverse effects of As,
      sensitive appropriate biomarkers are still required for studies of
      environmental epidemiology. A review of the literature has shown that various
      biomarkers are used for such research. Their limits and advantages are
      highlighted in this paper: (i) the detection of As or its derivatives in the
      blood is an indication of the dose ingested but it is not evidence of chronic
      intoxication. (ii) The detection of As in urine is an indispensible procedure
      because it is a good marker for internal dose. It has been demonstrated to
      correlate well for a number of chronic effects related to As levels in drinking
      water. However confounding factors must be taken into account to avoid
      misinterpretation and this may require As speciation. (iii) As in the hair and
      nails reflects the level of long term exposure but it is difficult to relate
      the level with the dose ingested. (iv) Some studies showed a correlation
      between urinary As and urinary and blood porphyrins. However, it is difficult
      to use only porphyrins as a biomarker in a population survey carried out
      without doing further studies. (v) Genotoxic effects are based on the
      characterization of these potential effects. Most studies have detected
      increases in DNA damage, sister chromatid exchange, micronuclei or chromosomal
      aberrations in populations exposed to As in drinking water. Micronuclei assay
      is the technique of choice to follow these populations, because it is sensitive
      and easy to use.
      To conclude, whatever epidemiological studies are, the
      urinary and toenail biomarkers are useful to provide indications of internal
      dose. Moreover, micronuclei assay can be complementary use as biomarker of
      early effects.

      Arsenic Exposure and
      Toxicology: A Historical Perspective. 2011. MF Hughes, BD Beck, Y Chen, AS
      Lewis, DJ Thomas. Toxicol. Sci. 123(2): 305-332.

      The metalloid arsenic is a natural environmental contaminant
      to which humans are routinely exposed in food, water, air, and soil. Arsenic
      has a long history of use as a homicidal agent, but in the past 100 years
      arsenic, has been used as a pesticide, a chemotherapeutic agent and a
      constituent of consumer products. In some areas of the world, high levels of
      arsenic are naturally present in drinking water and are a toxicological
      concern. There are several structural forms and oxidation states of arsenic
      because it forms alloys with metals and covalent bonds with hydrogen, oxygen,
      carbon, and other elements. Environmentally relevant forms of arsenic are
      inorganic and organic existing in the trivalent or pentavalent state.
      Metabolism of arsenic, catalyzed by arsenic (+3 oxidation state)
      methyltransferase, is a sequential process of reduction from pentavalency to
      trivalency followed by oxidative methylation back to pentavalency. Trivalent
      arsenic is generally more toxicologically potent than pentavalent arsenic.
      Acute effects of arsenic range from gastrointestinal distress to death.
      Depending on the dose, chronic arsenic exposure may affect several major organ
      systems. A major concern of ingested arsenic is cancer, primarily of skin,
      bladder, and lung. The mode of action of arsenic for its disease endpoints is
      currently under study. Two key areas are the interaction of trivalent
      arsenicals with sulfur in proteins and the ability of arsenic to generate
      oxidative stress. With advances in technology and the recent development of
      animal models for arsenic carcinogenicity, understanding of the toxicology of
      arsenic will continue to improve.

      Critical windows of
      exposure for arsenic-associated impairment of cognitive function in pre-school
      girls and boys: a population-based cohort study.  2011.  JD
      Hamadani, F Tofail, B Nermell, R Gardner, S Shiraji,
      M Bottai, et al.  Int. J.
      Epidemiol.  40(6): 1593-1604.

      BACKGROUND: Exposure to arsenic through drinking water has
      been associated with impaired cognitive function in school-aged children in a
      few cross-sectional studies; however, there is little information on critical
      windows of exposure.
      METHODS: We conducted a population-based longitudinal study
      in rural Bangladesh.
      We assessed the association of arsenic exposure, based on urinary arsenic
      (U-As; twice during pregnancy and twice in childhood), with the development of
      about 1700 children at 5 years of age using Wechsler Pre-school and Primary Scale of Intelligence [intelligence quotient (IQ)].
      RESULTS: Median maternal U-As in pregnancy was 80 mu g/l
      (10-90 percentiles: 25-400 mu g/l). Children's urine contained 35 (12-155) mu
      g/l and 51 (20-238) mu g/l at 1.5 and 5 years, respectively. Using
      multivariable-adjusted regression analyses, controlling for all potential
      confounders and loss to follow-up, we found that verbal IQ (VIQ) and full scale
      IQ (FSIQ) were negatively associated with (log) U-As in girls. The associations
      were consistent, but somewhat stronger with concurrent arsenic exposure [VIQ: B
      = -2.4, 95% confidence interval (CI) = -3.8 to -1.1; FSIQ: B = -1.4, 95% CI =
      -2.7 to -0.1, n = 817), compared with that at 1.5 years (VIQ: B = -0.85, 95% CI
      = -2.1 to 0.4; FSIQ: B = -0.74, 95% CI = -1.9 to 0.4, n = 902), late gestation
      (VIQ: B = -1.52, 95% CI = -2.6 to -0.4; FSIQ: B = -1.35, 95% CI = -2.4 to -0.3,
      n = 874) and early gestation (VIQ: B = -1.23, 95% CI = -2.4 to -0.06; FSIQ: B =
      -0.92, 95% CI = -2.0 to -0.2, n = 833). In boys, U-As showed consistently low
      and non-significant associations with all IQ measures. An effect size calculation
      indicated that 100 mu g/l U-As was associated with a decrement of 1-3 points in
      both VIQ and FSIQ in girls.
      CONCLUSION: We found adverse effects of arsenic exposure on
      IQ in girls, but not boys, at 5 years of age.

      Arsenic Exposure and
      Motor Function among Children in Bangladesh.  2011.  F Parvez, GA Wasserman, P Factor-Litvak, XH Liu, V Slavkovich, AB Siddique, et al.  Environ. Health Perspect.  119(11): 1665-1670.

      BACKGROUND: Several reports indicate that drinking water
      arsenic (WAs) and manganese (WMn) are associated with children's intellectual
      function. Very little is known, however, about possible associations with other
      neurologic outcomes such as motor function.
      METHODS: We investigated the associations of WAs and WMn
      with motor function in 304 children in Bangladesh, 8-11 years of age. We
      measured As and Mn concentrations in drinking water, blood, urine, and
      toenails. We assessed motor function with the Bruininks-Oseretsky test, version
      2, in four subscales-fine manual control (FMC), manual coordination (MC), body
      coordination (BC), and strength and agility-which can be summarized with a
      total motor composite score (TMC).
      RESULTS: Log-transformed blood As was associated with
      decreases in TMC [beta = -3.63; 95% confidence interval (CI): -6.72, -0.54; p
      < 0.01], FMC (beta = -1.68; 95% CI: -3.19, -0.18; p < 0.05), and BC (beta
      = -1.61; 95% CI: -2.72, -0.51; p < 0.01), with adjustment for sex, school
      attendance, head circumference, mother's intelligence, plasma ferritin, and
      blood Mn, lead, and selenium. Other measures of As exposure (WAs, urinary As,
      and toenail As) also were inversely associated with motor function scores,
      particularly TMC and BC. Square-transformed blood selenium was positively
      associated with TMC (beta = 3.54; 95% CI: 1.10, 6.0; p < 0.01), FMC (beta =
      1.55; 95% CI: 0.40, 2.70; p < 0.005), and MC (beta = 1.57; 95% CI: 0.60,
      2.75; p < 0.005) in the unadjusted models. Mn exposure was not significantly
      associated with motor function.
      CONCLUSION: Our research demonstrates an adverse association
      of As exposure and a protective association of Se on motor function in

      Poisoning the mind:
      Arsenic contamination of drinking water wells and children's educational
      achievement in rural Bangladesh.
      2011.  MN Asadullah and N Chaudhury.  Econ. Educ. Rev.  30(5): 873-888.

      Bangladesh has experienced the largest mass poisoning of a population in history owing to
      contamination of groundwater with naturally occurring inorganic arsenic.
      Prolonged drinking of such water risks development of diseases and therefore
      has implications for children's cognitive and psychological development. This
      study examines the effect of arsenic contamination of tubewells, the primary
      source of drinking water at home, on the learning outcome of school-going
      children in rural Bangladesh using recent nationally representative data on secondary school children. We
      unambiguously find a negative and statistically significant correlation between
      mathematics scores and arsenic-contaminated drinking tubewells at home, net of
      the child's socio-economic status, parental background and school specific
      unobserved correlates of learning. Similar correlations are found for an
      alternative measure of student achievement and subjective well-being (i.e.
      self-reported measure of life satisfaction), of the student. We conclude by
      discussing the policy implication of our findings in the context of the current
      debate over the adverse effect of arsenic poisoning on children.

      Persistent Exposure to Arsenic via Drinking Water in Rural Bangladesh Despite Major Mitigation Efforts. 2011. R Gardner, J Hamadani, M
      Grander, F Tofail, B Nermell, B Palm, et
      al.  Am. J. Pub. Health. 101(1): S333-S338.

      OBJECTIVES. Elevated arsenic levels
      in tube-well water in Bangladesh have prompted extensive mitigation projects. We evaluated the effectiveness of
      long-term mitigation efforts by longitudinally measuring arsenic exposure in
      pregnant women and their children, the most susceptible population groups.
      METHODS. The study was nested in a
      population-based nutrition intervention in Mat lab, Bangladesh. Mother child pairs
      (n=1951) were followed from 2001 to 2003, beginning in early gestation and
      continuing to 5 years postpartum. We measured arsenic concentrations in urine
      (U-As) of the 5-year-old children by using high-performance liquid
      chromatography online with hydride generation and inductively coupled plasma
      mass spectrometry and compared them with earlier childhood U-As and maternal
      U-As during pregnancy.
      RESULTS. Children had elevated U-As
      at 5 years old (median=51 mu g/L, 5th-95th percentiles=16-355 mu g/L), and U-As
      distribution was similar to that observed in the mothers during gestation.
      Children's U-As at 5 years old significantly correlated with their U-As at 1.5
      years old and to maternal U-As during early and late gestation.
      CONCLUSIONS. Despite major
      mitigation efforts, arsenic exposure remains highly elevated in rural Bangladesh.
      Further mitigation strategies are required and must be rigorously evaluated for
      long-term efficacy.


      Impact on arsenic
      exposure of a growing proportion of untested wells in Bangladesh. 2012. CM George, JH Graziano, JL Mey, A van Geen.Environ. Health. 11(7).

      BACKGROUND: In many areas of Bangladesh, it has been more than
      six years since a national campaign to test tubewells for arsenic (As) was
      conducted. Many households therefore draw their water for drinking and cooking
      from untested wells.
      METHODS: A household drinking water survey of 6646
      households was conducted in Singair upazilla of Bangladesh. A subset of 795
      untested wells used by 1000 randomly selected households was tested in the
      field by trained village workers with the Hach EZ kit, using an extended
      reaction time of 40 min, and in the laboratory by high-resolution
      inductively-coupled plasma-mass spectrometry (HR ICP-MS).
      RESULTS: The household survey shows that more than 80% of
      the wells installed since the national testing campaign in this area were
      untested. Less than 13% of the households with untested wells knew where a
      low-As well was located near their home. Village workers using the Hach EZ kit
      underestimated the As content of only 4 out of 795 wells relative to the
      Bangladesh standard. However, the As content of 168 wells was overestimated
      relative to the same threshold.
      CONCLUSION: There is a growing need for testing tubewells in
      areas of Bangladesh where As concentrations in groundwater are elevated. This could be achieved by
      village workers trained to use a reliable field kit. Such an effort would
      result in a considerable drop in As exposure as it increases the opportunities
      for well switching by households.


      Dissolved organic
      carbon from the traditional jute processing technique and its potential
      influence on arsenic enrichment in the Bengal Delta.  2012.  SH Farooq, D Chandrasekharam, G Abbt-Braun, Z
      Berner, S Norra, D Stuben.  Appl.
      Geochem.  27(1): 292-303.

      Dissolved organic C (DOC) plays an important role in the
      mobilization of As from sediments. In West Bengal,
      the widely used technique for obtaining jute fiber involves retting of the jute
      plant in ponds (hereafter such ponds are termed jute decomposing ponds) for
      several weeks, which produces significant amounts of DOC in the ponds. These
      ponds thus act as point sources of DOC and supply huge quantities of organic C
      to the Bengal Delta sediments. This study has been carried out to investigate
      the role of such DOC in enriching the groundwater with As in the Bengal Delta.
      Data clearly show that due to the effect of DOC, As is mobilized from the upper
      2.6 m of the sediment profile, and is fixed between 2.6 and 6.1 m, while the
      lower part (6.1-9 m) largely remains unaffected. The reducing conditions mainly
      developed due to the decay of the percolating DOC seem to help the mobilization
      and transportation of As and other redox sensitive elements (Fe, Mn), as well
      as elements (Cu, Zn) attached to oxy-hydroxides of those redox-sensitive
      elements. Experiments also indicate that if the DOC production at the surface
      continues for a longer period of time, the zone of As fixation (2.6-6.1 m) may
      get shifted further downwards and ultimately intercept the water table
      resulting in As enrichment of groundwater.

      Effect of groundwater
      flow on forming arsenic contaminated groundwater in Sonargaon, Bangladesh.  2011.  S Nakaya, H Natsume, H Masuda, M Mitamura, DK Biswas and AA Seddique. J. Hydrol.  409(3-4): 724-736.

      Three-dimensional groundwater flow in Sonargaon, Bangladesh is numerically simulated in order to evaluate the flow paths of As-contaminated
      drinking groundwater in the Holocene aquifer of the Ganges-Blamaptra-Meghna
      delta plain over a recent 30-year period. The model indicates that vertical
      infiltration of surface groundwater into the shallow Holocene aquifer occurs
      frequently in the Ganges-Blamaptra-Meghna delta plain. It predicts that the
      water recharged from ground surface moves approximately 10-20 m vertically
      downward beneath the flood plain, with a gradually increasing horizontal flow,
      toward the underlying Pleistocene middle mud layer (aquitard). The model also
      predicts that groundwaters containing highest As concentrations (>700 mu
      g/L) are formed on the vertical groundwater flow paths where surface water recharges
      the Holocene aquifer and not on the horizontal flow paths. Combining with the
      groundwater chemistry, reducing groundwater condition is not essential for the
      As-contaminated groundwater of the studied area in the Ganges delta plain.

      Arsenic migration to
      deep groundwater in Bangladesh influenced by adsorption and water demand.  2011.  KA Radloff, Y Zheng, HA
      Michael, M Stute, BC Bostick, I Mihajlov, et al.  Nat. Geosci.  4(11): 793-798.

      The consumption of shallow groundwater with elevated
      concentrations of arsenic is causing widespread disease in many parts of South
      and Southeast Asia. In the Bengal Basin,
      a growing reliance on groundwater sourced below 150-m depth-where arsenic
      concentrations tend to be lower-has reduced exposure. Groundwater flow
      simulations have suggested that these deep waters are at risk of contamination
      due to replenishment with high-arsenic groundwater from above, even when deep
      water pumping is restricted to domestic use. However, these simulations have
      neglected the influence of sediment adsorption on arsenic migration. Here, we
      inject arsenic-bearing groundwater into a deep aquifer zone in Bangladesh, and
      monitor the reduction in arsenic levels over time following stepwise withdrawal
      of the water. Arsenic concentrations in the injected water declined by 70%
      after 24 h in the deep aquifer zone, owing to adsorption on sediments;
      concentrations of a co-injected inert tracer remain unchanged. We incorporate
      the experimentally determined adsorption properties of sands in the deep
      aquifer zone into a groundwater flow and transport model covering the Bengal Basin.
      Simulations using present and future scenarios of water-use suggest that
      arsenic adsorption significantly retards transport, thereby extending the area
      over which deep groundwater can be used with low risk of arsenic contamination.
      Risks are considerably lower when deep water is pumped for domestic use alone.
      Some areas remain vulnerable to arsenic intrusion, however, and we suggest that
      these be prioritized for monitoring.

      Perennial ponds are
      not an important source of water or dissolved organic matter to groundwaters with
      high arsenic concentrations in West Bengal, India.  2011.  S
      Datta, AW Neal, TJ Mohajerin, T Ocheltree, BE Rosenheim, CD White, KH Johannesson. Geophys. Res. Lett. 38: L20404.

      Arsenic (As) concentrations and stable hydrogen (delta(2)H) and
      oxygen (delta(18)O) isotope ratios of surface and groundwaters from a
      representative site in West Bengal, India, are reported. Shallow groundwaters
      (<= 35 m) from the study site have among the highest As concentrations
      measured in the entire Bengal Basin, reaching values in excess of 4600 mu g
      kg(-1). Stable isotope ratios of waters from constructed, perennial ponds
      indicate the ponds are chiefly recharged during the summer monsoon, and
      subsequently undergo extensive evaporation during the dry (winter) season. In
      contrast, groundwaters with high As concentrations plot along the local
      meteoric water line (LMWL) near where the annual, volume-weighted mean
      precipitation values for delta(2)H and delta(18)O would plot. The stable
      isotope data demonstrate that groundwaters are directly recharged by local
      precipitation without significant evaporation, and thus are not recharged by,
      nor mixed with, the pond waters. Furthermore, reactive transport modeling
      indicates that dissolved organic matter (DOM) derived from pond waters does not
      fuel microbial respiration and As mobilization at depth in the underlying
      aquifer because travel times for pond-derived DOM exceed groundwater ages by
      thousands of years. Instead, organic matter within the aquifer sediments must
      drive dissimilatory iron reduction and As release to groundwaters.   



      Testing Tubewell
      Platform Color As A Rapid Screening Tool For Arsenic And Manganese In Drinking
      Water Wells.  2012.  A
      Biswas, B Nath, P Bhattacharya, D Halder, AK Kundu, U Mandal, et al.  Environ. Sci. Technol.  46(1):434-440.

      A low-cost rapid screening tool for arsenic (As) and
      manganese (Mn) in groundwater is urgently needed to formulate mitigation
      policies for sustainable drinking water supply. This study attempts to make
      statistical comparison between tubewell (TW) platform color and the level of As
      and Mn concentration in groundwater extracted from the respective TW (n = 423),
      to validate platform color as a screening tool for As and Mn in groundwater.
      The result shows that a black colored platform with 73% certainty indicates
      that well water is safe from As, while with 84% certainty a red colored
      platform indicates that well water is enriched with As, compared to WHO
      drinking water guideline of 10 mu g/L. With this guideline the efficiency,
      sensitivity, and specificity of the tool are 79%, 77%, and 81%, respectively.
      However, the certainty values become 93% and 38%, respectively, for black and
      red colored platforms at 50 mu g/L, the drinking water standards for India and Bangladesh. The respective
      efficiency, sensitivity, and specificity are 65%, 85%, and 59%. Similarly for Mn,
      black and red colored platform with 78% and 64% certainty, respectively,
      indicates that well water is either enriched or free from Mn at the Indian
      national drinking water standard of 300 mu g/L. With this guideline the
      efficiency, sensitivity, and specificity of the tool are 71%, 67%, and 76%,
      respectively. Thus, this study demonstrates that TW platform color can be
      potentially used as an initial screening tool for identifying TWs with elevated
      dissolved As and Mn, to make further rigorous groundwater testing more
      intensive and implement mitigation options for safe drinking water supplies. 

      Feasibility study of
      rainwater harvesting system in Sylhet City.  2012.  R Alam, G Munna, MAI Chowdhury, MSKA Sarkar, M Ahmed, MT Rahman, et al.  Environ.
      Monit. Assess.  184(1): 573-580.
      In rural areas in Bangladesh, groundwater is the
      principal source of water supply. This underground water is available in
      considerable amount in shallow aquifers. It is free from pathogenic
      microorganisms and hence water-borne diseases. In plain lands, other than hilly
      areas, water supply to 97% rural population comes from tube-wells, which is
      regarded to be a phenomenal achievement in preserving public health. Besides, a
      dependable water supply system all throughout the country is offset by two
      factors: (a) high salinity in surface plus groundwater in coastal areas; (b)
      want of suitable groundwater aquifers in hilly areas and the high cost of setting
      up tube-wells due to deep underground water table and stony layers. However,
      presence of arsenic in underground water now poses a serious threat to the
      success once made in water supply by setting up of manually operated tube-wells
      in the village areas-the achievement is now on the brink of total collapse. In
      about 61 districts out of 64, presence of arsenic exceeds a quantity of 0.05
      mg/1, a permissible limit as per Bangladeshi water quality standard. Harvesting
      rainwater can be a pragmatic solution to this problem, which is common in many
      places in Sylhet especially in the hilly areas on the north eastern part of the
      city. This can be an alternative source of drinking water because of
      availability of rainwater from March to October. Heavy rain occurs from end of
      May till mid September, which is commonly known as the rainy season. This paper
      focuses on the possibility of harvesting rainwater in rural communities and
      thickly populated urban areas of Sylhet. It also demonstrates the scopes of
      harvesting rainwater using simple and low-cost technology. With setting up of a
      carefully planned rainwater storage tank, a family can have all of its drinking
      water from rain. Planned use of rainwater through rainwater harvesting in the
      roof catchments may fulfill the entire annual domestic water demand of a family
      in the rural areas of Bangladesh.

      Iron and aluminium
      based adsorption strategies for removing arsenic from water.  2011.  DE Giles, M Mohapatra, TB Issa, S Anand, P Singh.  J. Env. Manage.  92(12):

      Arsenic is a commonly occurring toxic metal in natural
      systems and is the root cause of many diseases and disorders. Occurrence of
      arsenic contaminated water is reported from several countries all over the
      world. A great deal of research over recent decades has been motivated by the
      requirement to lower the concentration of arsenic in drinking water and the
      need to develop low cost techniques which can be widely applied for arsenic
      removal from contaminated water. This review briefly presents iron and
      aluminium based adsorbents for arsenic removal. Studies carried out on
      oxidation of arsenic(III) to arsenic(V) employing various oxidising agents to
      facilitate arsenic removal are briefly mentioned. Effects of competing ions,
      As:Fe ratios, arsenic(V) vs. arsenic(III) removal using ferrihydrite as the
      adsorbent have been discussed. Recent efforts made for investigating arsenic
      adsorption on iron hydroxides/oxyhydroxides/oxides such as granular ferric
      hydroxide, goethite, akaganeite, magnetite and haematite have been reviewed.
      The adsorption behaviours of activated alumina, gibbsite, bauxite, activated
      bauxite, layered double hydroxides are discussed. Point-of-use adsorptive
      remediation methods indicate that Sono Arsenic filter and Kanchan (TM) Arsenic
      filter are in operation at various locations of Bangladesh and Nepal.
      The relative merits and demerits of such filters have been discussed.
      Evaluation of kits used for atsite arsenic estimation by various researchers
      also forms a part of this review.

      Combination of
      hydrous iron oxide precipitation with zeolite filtration to remove arsenic from
      contaminated water.  2011.  ZH Li, WT Jiang, JS Jean, HL Hong, LB Liao
      and GC Lv.  Desalination.  280(1-3):

      Groundwater arsenic contamination imposes a great threat to
      people worldwide. Thus, developing new and cost-effective methods to remove
      arsenic from groundwater and drinking water becomes imminent. With several
      patents granted, using hydrous iron/aluminum hydroxides (HFO/HAO) to remove
      arsenic from water is a proven technology. The method involved in addition of
      ferric iron or alumina to induce precipitation for arsenic sorption. Currently
      used filtration media were limited to sand, granular activated carbon, granular
      activated alumina. In this research, a natural clinoptilolite zeolite was used
      as the filtration media to remove arsenic-containing HFO/HAO co-precipitates.
      The results showed that removal of As from water can be achieved relatively
      effectively using zeolites as filtration media after HFO precipitation and As
      sorption on precipitated HFO. The As(III) and As(V) sorption capacities on
      precipitated HFO were 48 and 68 mg/g, respectively. The optimal pH for maximum
      As removal was in neutral range between 6.5 and 9. Depending on the initial As
      concentration and redox conditions, the minimal Fe(III) needed to reduce the As
      concentration below standard would be around 10 mg/L The method could achieve
      better results when the water was under oxic condition, particularly in the
      presence of extensive dissolved Fe.


      Straighthead: An Impending Threat to Sustainable Rice Production in South and South-East Asia!  2011.  MA Rahman, MM Rahman, H Hasegawa.  Bull.
      Environ. Contamin. Toxicol.  88(3):

      Straighthead is a physiological disorder of rice (Oryza
      sativa L.) that results in sterile florets with distorted lemma and palea, and
      the panicles or heads may not form at all in extreme cases. Heads remain
      upright at maturity, hence the name 'straighthead'. The diseased panicles may
      not emerge from the flag leaf sheath when the disease is severe. Straighthead
      disease in rice results in poorly developed panicles and significant yield
      loss. Although other soil physicochemical factors involved, arsenic
      contamination in soil has also been reported to be closely associated with
      straighthead of rice. Monosodium methanearsonate has been a popular herbicide
      in cotton production in the USA,
      which has shown to cause injuries in rice that are similar to straighthead.
      Since toxicity of inorganic arsenic (iAs) is higher than other forms of
      arsenic, it may produce a more severe straighthead disorder in rice. The use of
      iAs-rich groundwater for irrigation, and the increase of iAs concentrations in
      agricultural soil in arsenic epidemic South and South-East Asia may cause a high incidence of straighthead in rice, resulting
      in a threat to sustainable rice production in this region.

      Variation in grain
      arsenic assessed in a diverse panel of rice (Oryza sativa) grown in multiple
      sites.  2011.  GJ Norton, SRM Pinson, J Alexander, S McKay,
      H Hansen, GL Duan, et al.  New
      Phytol.  193(3): 650-664. 

      Inorganic arsenic (Asi) in rice (Oryza sativa) grains is a
      possible threat to human health, with risk being strongly linked to total
      dietary rice consumption and consumed rice Asi content. This study aimed to
      identify the range and stability of genetic variation in grain arsenic (As) in
      rice. Six field trials were conducted (one each in Bangladesh and China, two in
      Arkansas, USA over 2 yr, and two in Texas, USA comparing flooded and nonflood
      treatments) on a large number of common rice cultivars (c. 300) representing
      genetic diversity among international rice cultivars. Within each field there
      was a 334 fold range in grain As concentration which varied between rice
      subpopulations. Importantly, Asi correlated strongly with total As among a
      subset of 40 cultivars harvested in Bangladesh and China.
      Genetic variation at all field sites was a large determining factor for grain
      As concentration, indicating that cultivars low in grain As could be developed
      through breeding. The temperate japonicas exhibited lower grain As compared
      with other subpopulations. Effects for year, location and flooding management
      were also statistically significant, suggesting that breeding strategies must take
      into account environmental factors.

      Deficit irrigation:
      An option to mitigate arsenic load of rice grain in West Bengal, India.  2012.  S Sarkar, B Basu, CK Kundu, and PK Patra.  Agr.
      Ecosyst. Environ.  146(1): 147-152.
      Farmers in arsenic (As) contaminated areas of West Bengal,
      India grow rice during dry months (January to April) and use underground water
      for irrigation with As concentration above WHO defined critical (0.01 mg l(-1))
      limit. In each season they add 50-150 mg As per m(2) soil area. Thus growing
      rice under deficit irrigation in these areas will reduce As load in
      soil-root-shoot-leaf-grain continuum of rice ecosystem. Suitable deficit
      irrigation system has to be screened so that As load will decrease with
      insignificant reduction in grain yield. With this objective, rice grown under
      four irrigation regimes (i) continuous ponding (CP), (ii) intermittent ponding
      (IP), (iii) saturation (SAT) and (iv) aerobic (AER) was tested to assess the
      arsenic load in soil and various parts of rice on 45 and 80 days after
      transplanting (DAT). Conditions described in treatments ii, iii and iv were
      imposed during 15-45 DAT. Highest value (18.18 and 18.74 mg kg(-1)) of soil
      arsenic was attained under CP followed by IP. SAT and AER. Root arsenic content
      under AER at 45 and 80 DAT was at the lowest level (6.14 and 20.54 mg kg(-1))
      and this was 31 and 7.0% lower as compared to CP. As content in leaf and grain
      attained the lowest values under IP. Grain yield insignificantly differed under
      IP (4.33 Mg ha(-1)) over CP (4.69 Mg ha(-1)). Compared to soil As, As added
      through irrigation showed stronger relationship with As status of various plant
      parts. Imposition of IP only during vegetative stage was found to be optimum in
      terms of reduction of As content in straw and grain respectively by 23 and 33%
      over farmers irrigation practice with insignificant decrease in grain yield.

      Factors affecting
      paddy soil arsenic concentration in Bangladesh: Prediction and
      uncertainty of geostatistical risk mapping.  2011.  ZU Ahmed, GM Panaullah, SD DeGloria, JM Duxbury.  Sci. Tot. Env.  412: 324-335.

      Knowledge of the spatial correlation of soil arsenic (As)
      concentrations with environmental variables is needed to assess the nature and
      extent of the risk of As contamination from irrigation water in Bangladesh.
      We analyzed 263 paired groundwater and paddy soil samples covering highland
      (HL) and medium highland-1 (MHL-1) land types for geostatistical mapping of
      soil As and delineation of As contaminated areas in Tala Upazilla, Satkhira
      district. We also collected 74 non-rice soil samples to assess the baseline
      concentration of soil As for this area. The mean soil As concentrations (mg/kg)
      for different land types under rice and non-rice crops were: rice-MHL-1
      (21.2)>rice-HL (14.1)>non-rice-MHL-1 (11.9)>non-rice-HL (7.2).
      Multiple regression analyses showed that irrigation water As. Fe, land
      elevation and years of tubewell operation are the important factors affecting
      the concentrations of As in HL paddy soils. Only years of tubewell operation
      affected As concentration in the MHL-1 paddy soils. Quantitatively similar
      increases in soil As above the estimated baseline-As concentration were
      observed for rice soils on HL and MHL-1 after 6-8 years of groundwater
      irrigation, implying strong retention of As added in irrigation water in both
      land types. Application of single geostatistical methods with secondary
      variables such as regression kriging (Rio) and
      ordinary co-kriging (OCK) gave little improvement in prediction of soil As over
      ordinary kriging (OK). Comparing single prediction methods, kriging within strata
      (KWS), the combination of Rio for HL and OCK for MHL-1, gave more accurate soil
      As predictions and showed the lowest misclassification of declaring a location
      "contaminated" with respect to 14.8 mg As/kg, the highest value
      obtained for the baseline soil As concentration. Prediction of soil As buildup
      over time indicated that 75% or the soils cropped to rice would contain at
      least 30 mg/L As by the year 2020.

      Arsenic contamination
      in sesame and possible mitigation through organic interventions in the lower
      Gangetic Plain of West Bengal, India.  2011.  B Sinha, K Bhattacharyya, PK Giri, and S Sarkar.  J. Sci.
      Food Agr.  91(15): 2762-2767.

      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.

      Defining the
      distribution of arsenic species and plant nutrients in rice (Oryza sativa L.)
      from the root to the grain.  2011.  AL Seyfferth, SM Webb, JC
      Andrews, S Fendorf.  Geochim.
      Cosmochim. Ac.  75(21): 6655-6671.

      The transport mechanisms of As from contaminated soil or
      irrigation water into roots and subsequently into grain, and the As species
      distribution-a toxicity determinant, is critical for assessing health risks
      imposed by As. However, the commonly-employed extraction of plant material with
      trifluoroacetic acid (TFA) has not proven successful in preserving inorganic As
      species. Synchrotron-based spectroscopic techniques are useful for discerning
      elemental distributions and chemical speciation of elements in situ. Here, we
      both characterize the mineral phases of Fe coatings on rice roots, and quantify
      plant nutrients and As species in situ on roots and grain samples. Arsenic in
      rice grains was present in bran layers as oxidized As (69-88% as As(V)(i) and
      12-31% as DMA) and in the germ as a mixture of As(V)(i) and As(III)(i), but was
      non-detected from the endosperm, which is consistent with previous findings.
      The extent of Fe coatings on rice roots was variable and, when present,
      consisted of lepidocrocite (gamma-FeOOH), goethite (alpha-FeOOH) and
      ferrihydrite (Fe(OH)(3)center dot nH(2)O). Arsenic was co-located with root Fe
      coatings, but our findings indicate that Fe is not a direct interceptor of As
      uptake, and is rather a bulk scavenger mostly near the air-water interface. On
      whole root mounts with Fe plaque, arsenic was present as mixed species of
      As(V)(i) (44-66%) and As(III)(i) (34-56%). Within a root cross-section,
      oxidized As species were dominant in the xylem (86% as As(V)(i) and 14% as DMA)
      whereas mostly reduced species (71% as As(III)(i), 29% as AsGlu(3)) resided
      within a vacuole adjacent to the xylem. This finding contrasts the prevailing
      view that As(V)(i) is rapidly reduced in roots and transported to shoots as
      As(III)(i), and points to the importance of interspecies differences in
      As-uptake dynamics.  

      High levels of
      inorganic arsenic in rice in areas where arsenic-contaminated water is used for
      irrigation and cooking. 2011.  MA Rahman, H Hasegawa.  Sci. Tot. Env.  409(22):

      Rice is the staple food for the people of arsenic endemic
      South (S) and South-East (SE) Asian countries. In this region, arsenic
      contaminated groundwater has been used not only for drinking and cooking
      purposes but also for rice cultivation during dry season. Irrigation of
      arsenic-contaminated groundwater for rice cultivation has resulted high
      deposition of arsenic in topsoil and uptake in rice grain posing a serious
      threat to the sustainable agriculture in this region. In addition, cooking rice
      with arsenic-contaminated water also increases arsenic burden in cooked rice.
      Inorganic arsenic is the main species of S and SE Asian rice (80 to 91% of the
      total arsenic), and the concentration of this toxic species is increased in
      cooked rice from inorganic arsenic-rich cooking water. The people of Bangladesh and West Bengal (India), the
      arsenic hot spots in the world, eat an average of 450 g rice a day. Therefore,
      in addition to drinking water, dietary intake of arsenic from rice is supposed
      to be another potential source of exposure, and to be a new disaster for the
      population of S and SE Asian countries. Arsenic speciation in raw and cooked
      rice, its bioavailability and the possible health hazard of inorganic arsenic
      in rice for the population of S and SE Asia have
      been discussed in this review.


      Impact of Arsenic Pollution
      on Spatial Distribution of Human Development Index.  2011. SR Samadder.  KSCE J.
      Civ. Eng.  15(6): 975-982.

      This paper reports the impact of arsenic pollution on Human
      Development Index (HDI) that shows the development standard of a society,
      country, or a region. HDI is the average of the three dimension indices of
      Education, Gross Domestic Product (GDP), and Life Expectancy. The study area
      includes six peripheral administrative blocks of the district Murshidabad of
      West Bengal, India. About 1.07 million people are exposed to arsenic pollution
      in this area of whom 0.32 million people are exposed to arsenic concentration
      above 0.05 mg/L, the WHO maximum permissible level of arsenic in drinking
      water. Arsenic concentration in groundwater in this area ranges from 0 to 0.35
      mg/L. Three dimension indices of HDI were calculated to observe the impact of
      arsenic pollution on HDI. Life expectancy index was the main cause of reduction
      in HDI as it was affected by arsenic pollution in groundwater. The study
      revealed that HDI was highly affected by the arsenic pollution in all six
      blocks analyzed as HDI was reduced up to 25% due to reduction in life
      expectancy because of arsenic pollution in groundwater. Blocks Lalgola and
      Raninagar-2 are of major concern as the observed reduction in HDI was as high
      as 20 to 25% in some of the mouzas (sub-areas/groups of villages and hamlets)
      of these two blocks where arsenic pollution in groundwater was very high (0.25
      to 0.35 mg/L). The study demonstrated a quantitative and widely acceptable
      method for the public health engineers to go for proper planning of alternative
      water supply schemes and management of arsenic mitigation options on a priority

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