Alexander van Geen

Publications (64)329.28 Total impact

• Article: Advection of surface-derived organic carbon fuels microbial reduction in Bangladesh groundwater.

  Brian J Mailloux, Elizabeth Trembath-Reichert, Jennifer Cheung, Marlena Watson, Martin Stute, Greg A Freyer, Andrew S Ferguson, Kazi Matin Ahmed, Md Jahangir Alam, Bruce A Buchholz, James Thomas, Alice C Layton, Yan Zheng, Benjamin C Bostick, Alexander van Geen
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  ABSTRACT: Chronic exposure to arsenic (As) by drinking shallow groundwater causes widespread disease in Bangladesh and neighboring countries. The release of As naturally present in sediment to groundwater has been linked to the reductive dissolution of iron oxides coupled to the microbial respiration of organic carbon (OC). The source of OC driving this microbial reduction-carbon deposited with the sediments or exogenous carbon transported by groundwater-is still debated despite its importance in regulating aquifer redox status and groundwater As levels. Here, we used the radiocarbon ((14)C) signature of microbial DNA isolated from groundwater samples to determine the relative importance of surface and sediment-derived OC. Three DNA samples collected from the shallow, high-As aquifer and one sample from the underlying, low-As aquifer were consistently younger than the total sediment carbon, by as much as several thousand years. This difference and the dominance of heterotrophic microorganisms implies that younger, surface-derived OC is advected within the aquifer, albeit more slowly than groundwater, and represents a critical pool of OC for aquifer microbial communities. The vertical profile shows that downward transport of dissolved OC is occurring on anthropogenic timescales, but bomb (14)C-labeled dissolved OC has not yet accumulated in DNA and is not fueling reduction. These results indicate that advected OC controls aquifer redox status and confirm that As release is a natural process that predates human perturbations to groundwater flow. Anthropogenic perturbations, however, could affect groundwater redox conditions and As levels in the future.
  Proceedings of the National Academy of Sciences 03/2013; · 9.68 Impact Factor
• Article: Arsenic Exposure from Drinking Water and QT-Interval Prolongation: Results from the Health Effects of Arsenic Longitudinal Study.

  Yu Chen, Fen Wu, Faruque Parvez, Alauddin Ahmed, Mahbub Eunus, Tyler R McClintock, Tazul I Patwary, Tariqul Islam, Anajan K Ghosal, Shahidul Islam, Rabiul Hasan, Diane Levy, Golam Sarwar, Vesna Slavkovich, Alexander van Geen, Joseph H Graziano, Habibul Ahsan
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  ABSTRACT: BACKGROUND: Arsenic exposure from drinking water has been associated with heart disease, but underlying mechanisms are uncertain. OBJECTIVE: To evaluate the association between history of arsenic exposure from drinking water and prolongation of heart rate-corrected QT (QTc), PR, and QRS intervals. METHOD: We conducted a study of 1,715 participants enrolled at baseline from the Health Effects of Arsenic Longitudinal Study. Arsenic exposure was measured in baseline well water and urine samples, and in urine samples collected during follow-up. Electrocardiogram evaluations were performed during 2005-2010, with an average time since baseline of 5.9 years. RESULTS: The adjusted odds ratio [95% confidence interval (CI)] for QTc prolongation, defined as a QTc ≥ 450 ms in men and ≥ 460 ms in women, was 1.17 (1.01, 1.35) for a 1-standard deviation (SD) increase in well water arsenic (108.7 µg/L). The positive association appeared to be limited to women, with adjusted odds ratios of 1.24 (95% CI: 1.05, 1.47) and 1.24 (95% CI: 1.01, 1.53) for a 1-SD increases in baseline well water and urinary arsenic, respectively, compared with 0.99 (95% CI: 0.73, 1.33) and 0.86 (95% CI: 049, 1.51) in men. There were no apparent associations of baseline well water arsenic or urinary arsenic with PR or QRS prolongation in women or men. CONCLUSIONS: Long-term arsenic exposure from drinking water (average 95 µg/L; range, 0.1-790 µg/L) was associated with subsequent QT-interval prolongation in women. Future longitudinal studies with repeated ECG measurements would be valuable to assess the influence of changes in exposure.
  Environmental Health Perspectives 02/2013; · 7.04 Impact Factor
• Source

  Available from: Peter S. K. Knappett

  Article: Unsealed tubewells lead to increased fecal contamination of drinking water.

  Peter S K Knappett, Larry D McKay, Alice Layton, Daniel E Williams, Md J Alam, Brian J Mailloux, Andrew S Ferguson, Patricia J Culligan, Marc L Serre, Michael Emch, Kazi M Ahmed, Gary S Sayler, Alexander van Geen
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  ABSTRACT: Bangladesh is underlain by shallow aquifers in which millions of drinking water wells are emplaced without annular seals. Fecal contamination has been widely detected in private tubewells. To evaluate the impact of well construction on microbial water quality 35 private tubewells (11 with intact cement platforms, 19 without) and 17 monitoring wells (11 with the annulus sealed with cement, six unsealed) were monitored for culturable Escherichia coli over 18 months. Additionally, two 'snapshot' sampling events were performed on a subset of wells during late-dry and early-wet seasons, wherein the fecal indicator bacteria (FIB) E. coli, Bacteroidales and the pathogenicity genes eltA (enterotoxigenic E. coli; ETEC), ipaH (Shigella) and 40/41 hexon (adenovirus) were detected using quantitative polymerase chain reaction (qPCR). No difference in E. coli detection frequency was found between tubewells with and without platforms. Unsealed private wells, however, contained culturable E. coli more frequently and higher concentrations of FIB than sealed monitoring wells (p < 0.05), suggestive of rapid downward flow along unsealed annuli. As a group the pathogens ETEC, Shigella and adenovirus were detected more frequently (10/22) during the wet season than the dry season (2/20). This suggests proper sealing of private tubewell annuli may lead to substantial improvements in microbial drinking water quality.
  Journal of Water and Health 12/2012; 10(4):565-78. · 1.37 Impact Factor
• Article: Approaches to Increase Arsenic Awareness in Bangladesh: An Evaluation of an Arsenic Education Program.

  Christine Marie George, Pam Factor-Litvak, Khalid Khan, Tariqul Islam, Ashit Singha, Joyce Moon-Howard, Alexander van Geen, Joseph H Graziano
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  ABSTRACT: The objective of this study was to design and evaluate a household-level arsenic education and well water arsenic testing intervention to increase arsenic awareness in Bangladesh. The authors randomly selected 1,000 study respondents located in 20 villages in Singair, Bangladesh. The main outcome was the change in knowledge of arsenic from baseline to follow-up 4 to 6 months after the household received the intervention. This was assessed through a pre- and postintervention quiz concerning knowledge of arsenic. Respondents were between 18 and 102 years of age, with an average age of 37 years; 99.9% were female. The knowledge of arsenic quiz scores for study participants were significantly higher at follow-up compared with baseline. The intervention was effective in increasing awareness of the safe uses of arsenic-contaminated water and dispelling the misconception that boiling water removes arsenic. At follow-up, nearly all respondents were able to correctly identify the meaning of a red (contaminated) and green (arsenic safe) well relative to arsenic (99%). The educational program also significantly increased the proportion of respondents who were able to correctly identify the health implications of arsenic exposure. However, the intervention was not effective in dispelling the misconceptions in the population that arsenicosis is contagious and that illnesses such as cholera, diarrhea, and vomiting could be caused by arsenic. Further research is needed to develop effective communication strategies to dispel these misconceptions. This study demonstrates that a household-level arsenic educational program can be used to significantly increase arsenic awareness in Bangladesh.
  Health Education &amp Behavior 09/2012; · 1.54 Impact Factor
• Article: Evaluation of an arsenic test kit for rapid well screening in bangladesh.

  Christine Marie George, Yan Zheng, Joseph H Graziano, Shahriar Bin Rasul, Zakir Hossain, Jacob L Mey, Alexander van Geen
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  ABSTRACT: Exposure to arsenic in groundwater via drinking remains unabated for millions of villagers in Bangladesh. Since a blanket testing campaign using test kits almost a decade ago, millions of new wells have been installed but not tested; thus affordable testing is needed. The performance of the Arsenic Econo-Quick (EQ) kit was evaluated by blindly testing 123 wells in Bangladesh and comparing with laboratory measurements; 65 wells were tested twice. A subset of the same 123 wells was also tested using the Hach EZ kit in the field and the Digital Arsenator in the laboratory in Bangladesh. The EQ kit correctly determined the status of 110 (89%) and 113 (92%) out of 123 wells relative to the WHO guideline (10 μg/L) and the Bangladesh standard (50 μg/L), respectively. Relative to the WHO guideline, all misclassifications were underestimates for wells containing between >10 and 27 μg/L As. Relative to the Bangladesh As standard, over- and underestimates were evenly distributed. Given its short reaction time of 10 min relative to the Hach EZ and its lower cost compared to the Arsenator, the EQ kit appears to have several advantages for well testing in Bangladesh and elsewhere.
  Environmental Science & Technology 08/2012; 46(20):11213-9. · 4.80 Impact Factor
• Article: Comparison of fecal indicators with pathogenic bacteria and rotavirus in groundwater.

  Andrew S Ferguson, Alice C Layton, Brian J Mailloux, Patricia J Culligan, Daniel E Williams, Abby E Smartt, Gary S Sayler, John Feighery, Larry D McKay, Peter S K Knappett, Ekaterina Alexandrova, Talia Arbit, Michael Emch, Veronica Escamilla, Kazi Matin Ahmed, Md Jahangir Alam, P Kim Streatfield, Mohammad Yunus, Alexander van Geen
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  ABSTRACT: Groundwater is routinely analyzed for fecal indicators but direct comparisons of fecal indicators to the presence of bacterial and viral pathogens are rare. This study was conducted in rural Bangladesh where the human population density is high, sanitation is poor, and groundwater pumped from shallow tubewells is often contaminated with fecal bacteria. Five indicator microorganisms (E. coli, total coliform, F+RNA coliphage, Bacteroides and human-associated Bacteroides) and various environmental parameters were compared to the direct detection of waterborne pathogens by quantitative PCR in groundwater pumped from 50 tubewells. Rotavirus was detected in groundwater filtrate from the largest proportion of tubewells (40%), followed by Shigella (10%), Vibrio (10%), and pathogenic E. coli (8%). Spearman rank correlations and sensitivity-specificity calculations indicate that some, but not all, combinations of indicators and environmental parameters can predict the presence of pathogens. Culture-dependent fecal indicator bacteria measured on a single date did not predict total bacterial pathogens, but annually averaged monthly measurements of culturable E. coli did improve prediction for total bacterial pathogens. A qPCR-based E. coli assay was the best indicator for the bacterial pathogens. F+RNA coliphage were neither correlated nor sufficiently sensitive towards rotavirus, but were predictive of bacterial pathogens. Since groundwater cannot be excluded as a significant source of diarrheal disease in Bangladesh and neighboring countries with similar characteristics, the need to develop more effective methods for screening tubewells with respect to microbial contamination is necessary.
  Science of The Total Environment 06/2012; 431:314-22. · 3.29 Impact Factor
• Article: Association between arsenic exposure from drinking water and plasma levels of cardiovascular markers.

  Fen Wu, Farzana Jasmine, Muhammad G Kibriya, Mengling Liu, Oktawia Wójcik, Faruque Parvez, Ronald Rahaman, Shantanu Roy, Rachelle Paul-Brutus, Stephanie Segers, Vesna Slavkovich, Tariqul Islam, Diane Levy, Jacob L Mey, Alexander van Geen, Joseph H Graziano, Habibul Ahsan, Yu Chen
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  ABSTRACT: The authors conducted a cross-sectional study to assess the relation between arsenic exposure from drinking water and plasma levels of markers of systemic inflammation and endothelial dysfunction (matrix metalloproteinase-9, myeloperoxidase, plasminogen activator inhibitor-1, soluble E-selectin, soluble intercellular adhesion molecule-1 (ICAM-1), and soluble vascular adhesion molecule-1 (VCAM-1)) using baseline data from 668 participants (age, >30 years) in the Health Effects of Arsenic Longitudinal Study in Bangladesh (2007-2008). Both well water arsenic and urinary arsenic were positively associated with plasma levels of soluble VCAM-1. For every 1-unit increase in log-transformed well water arsenic (ln μg/L) and urinary arsenic (ln μg/g creatinine), plasma soluble VCAM-1 was 1.02 (95% confidence interval: 1.01, 1.03) and 1.04 (95% confidence interval: 1.01, 1.07) times greater, respectively. There was a significant interaction between arsenic exposure and higher body mass index, such that the increased levels of plasminogen activator inhibitor-1 and soluble VCAM-1 associated with arsenic exposure were stronger among people with higher body mass index. The findings indicate an effect of chronic arsenic exposure from drinking water on vascular inflammation and endothelial dysfunction that could be modified by body mass index and also suggest a potential mechanism underlying the association between arsenic exposure and cardiovascular disease.
  American journal of epidemiology 04/2012; 175(12):1252-61. · 5.59 Impact Factor
• Source

  Available from: Jacob L Mey

  Article: Impact on arsenic exposure of a growing proportion of untested wells in Bangladesh.

  Christine Marie George, Joseph H Graziano, Jacob L Mey, Alexander van Geen
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  ABSTRACT: 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. 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). 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. 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.
  Environmental Health 02/2012; 11:7. · 2.65 Impact Factor
• Article: Correction: Increase in Diarrheal Disease Associated with Arsenic Mitigation in Bangladesh.

  Jianyong Wu, Alexander van Geen, Kazi Matin Ahmed, Yasuyuki Akita, Janahgir Alam, Patricia J Culligan, Veronica Escamilla, John Feighery, Andrew S Ferguson, Peter Knappett, Brian J Mailloux, Larry D McKay, Marc L Serre, P Kim Streatfield, Mohammad Yunus, Michael Emch
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  ABSTRACT: [This corrects the article on p. e29593 in vol. 6.].
  PLoS ONE 01/2012; 7(1). · 4.09 Impact Factor
• Source

  Available from: Peter K Streatfield

  Article: Impact of tubewell access and tubewell depth on childhood diarrhea in Matlab, Bangladesh.

  Jianyong Wu, Mohammad Yunus, Peter Kim Streatfield, Alexander van Geen, Veronica Escamilla, Yasuyuki Akita, Marc Serre, Michael Emch
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  ABSTRACT: During the past three decades in Bangladesh, millions of tubewells have been installed to reduce the prevalence of diarrheal disease. This study evaluates the impacts of tubewell access and tubewell depth on childhood diarrhea in rural Bangladesh. A total of 59,796 cases of diarrhea in children under 5 were recorded in 142 villages of Matlab, Bangladesh during monthly community health surveys between 2000 and 2006. The location and depth of 12,018 tubewells were surveyed in 2002-04 and integrated with diarrhea and other data in a geographic information system. A proxy for tubewell access was developed by calculating the local density of tubewells around households. Logistic regression models were built to examine the relationship between childhood diarrhea, tubewell density and tubewell depth. Wealth, adult female education, flood control, population density and the child's age were considered as potential confounders. Baris (patrilineally-related clusters of households) with greater tubewell density were associated with significantly less diarrhea (OR (odds ratio) = 0.87, 95% confidence interval (CI): 0.85-0.89). Tubewell density had a greater influence on childhood diarrhea in areas that were not protected from flooding. Baris using intermediate depth tubewells (140-300 feet) were associated with more childhood diarrhea (OR = 1.24, 95% CI: 1.19-1.29) than those using shallow wells (10-140 feet). Baris using deep wells (300-990 feet) had less diarrheal disease than those using shallow wells, however, the difference was significant only when population density was low (< 1000 person/km(2)) or children were at the age of 13-24 months. Increased access to tubewells is associated with a lower risk of childhood diarrhea. Intermediate- depth wells are associated with more childhood diarrhea compared to shallower or deeper wells. These findings may have implications for on-going efforts to reduce exposure to elevated levels of arsenic contained in groundwater that is pumped in this study area primarily from shallow tubewells.
  Environmental Health 12/2011; 10:109. · 2.65 Impact Factor
• Source

  Available from: Peter S. K. Knappett

  Article: Implications of fecal bacteria input from latrine-polluted ponds for wells in sandy aquifers.

  Peter S K Knappett, Larry D McKay, Alice Layton, Daniel E Williams, Md J Alam, Md R Huq, Jacob Mey, John E Feighery, Patricia J Culligan, Brian J Mailloux, Jie Zhuang, Veronica Escamilla, Michael Emch, Edmund Perfect, Gary S Sayler, Kazi M Ahmed, Alexander van Geen
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  ABSTRACT: Ponds receiving latrine effluents may serve as sources of fecal contamination to shallow aquifers tapped by millions of tube-wells in Bangladesh. To test this hypothesis, transects of monitoring wells radiating away from four ponds were installed in a shallow sandy aquifer underlying a densely populated village and monitored for 14 months. Two of the ponds extended to medium sand. Another pond was sited within silty sand and the last in silt. The fecal indicator bacterium E. coli was rarely detected along the transects during the dry season and was only detected near the ponds extending to medium sand up to 7 m away during the monsoon. A log-linear decline in E. coli and Bacteroidales concentrations with distance along the transects in the early monsoon indicates that ponds excavated in medium sand were the likely source of contamination. Spatial removal rates ranged from 0.5 to 1.3 log(10)/m. After the ponds were artificially filled with groundwater to simulate the impact of a rain storm, E. coli levels increased near a pond recently excavated in medium sand, but no others. These observations show that adjacent sediment grain-size and how recently a pond was excavated influence the how much fecal contamination ponds receiving latrine effluents contribute to neighboring groundwater.
  Environmental Science & Technology 12/2011; 46(3):1361-70. · 4.80 Impact Factor
• Article: Manganese exposure from drinking water and children's academic achievement.

  Khalid Khan, Gail A Wasserman, Xinhua Liu, Ershad Ahmed, Faruque Parvez, Vesna Slavkovich, Diane Levy, Jacob Mey, Alexander van Geen, Joseph H Graziano, Pam Factor-Litvak
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  ABSTRACT: Drinking water manganese (WMn) is a potential threat to children's health due to its associations with a wide range of outcomes including cognitive, behavioral and neuropsychological effects. Although adverse effects of Mn on cognitive function of the children indicate possible impact on their academic achievement little evidence on this issue is available. Moreover, little is known regarding potential interactions between exposure to Mn and other metals, especially water arsenic (WAs). In Araihazar, a rural area of Bangladesh, we conducted a cross-sectional study of 840 children to investigate associations between WMn and WAs and academic achievement in mathematics and languages among elementary school-children, aged 8-11 years. Data on As and Mn exposure were collected from the participants at the baseline of an ongoing longitudinal study of school-based educational intervention. Annual scores of the study children in languages (Bangla and English) and mathematics were obtained from the academic achievement records of the elementary schools. WMn above the WHO standard of 400μg/L was associated with 6.4% score loss (95% CI=-12.3 to -0.5) in mathematics achievement test scores, adjusted for WAs and other sociodemographic variables. We did not find any statistically significant associations between WMn and academic achievement in either language. Neither WAs nor urinary As was significantly related to any of the three academic achievement scores. Our finding suggests that a large number of children in rural Bangladesh may experience deficits in mathematics due to high concentrations of Mn exposure in drinking water.
  NeuroToxicology 12/2011; 33(1):91-7. · 3.10 Impact Factor
• Article: Hand-pumps as reservoirs for microbial contamination of well water.

  Andrew S Ferguson, Brian J Mailloux, Kazi M Ahmed, Alexander van Geen, Larry D McKay, Patricia J Culligan
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  ABSTRACT: The retention and release of total coliforms and Escherichia coli was investigated in hand-pumps removed from tubewells tapping a faecally contaminated aquifer in Matlab, Bangladesh, and from a new hand-pump deliberately spiked with E. coli. All hand-pumps were connected to reservoirs of sterile water and flushed. Faecal coliforms were observed in the discharge from all three of the previously used hand-pumps, at concentrations comparable to levels measured in discharge when they were attached to the tubewells. During daily flushing of one of the previously used hand-pumps, the concentration of total coliforms in the discharge remained relatively constant (approximately 10³ MPN/100 mL). Concentrations of E. coli in the pump discharge declined over time, but E. coli was still detectable up to 29 days after the start of flushing. In the deliberately spiked hand-pump, E. coli was observed in the discharge over 125 days (t₅₀ = 8 days) and found to attach preferentially to elastomeric materials within the hand-pump. Attempts to disinfect both the village and new hand-pumps using shock chlorination were shown to be unsuccessful. These results demonstrate that hand-pumps can act as persistent reservoirs for microbial indicator bacteria. This could potentially influence drinking water quality and bias testing of water quality.
  Journal of Water and Health 12/2011; 9(4):708-17. · 1.37 Impact Factor
• Article: Bright Lines, Risk Beliefs, and Risk Avoidance: Evidence from a Randomized Intervention in Bangladesh

  Lori Snyder Bennear, Alessandro Tarozzi, Alexander Pfaff, H. B. Soumya, Kazi Matin Ahmed, Alexander Van Geen
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  ABSTRACT: This paper provides evidence on the effects of risk presentation on health behaviors using data from a cluster randomized controlled trial in risk presentation regarding arsenic in drinking water in Araihazar district of Bangladesh. The intervention was designed to test whether highlighting the existence of a gradient in arsenic risk — exposure risk increases with the level of arsenic and lower arsenic exposure is always better — led to better choices relative to “bright line” information provision that focuses on whether the arsenic level is above or below the country standard of 50 parts per billion (ppb).
  ERN: Search, Learning & Information Costs, & Behavior of Economic Agents (Topic). 09/2011;
• Source

  Available from: Peter S. K. Knappett

  Article: Impact of population and latrines on fecal contamination of ponds in rural Bangladesh.

  Peter S K Knappett, Veronica Escamilla, Alice Layton, Larry D McKay, Michael Emch, Daniel E Williams, R Huq, J Alam, Labony Farhana, Brian J Mailloux, Andy Ferguson, Gary S Sayler, Kazi M Ahmed, Alexander van Geen
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  ABSTRACT: A majority of households in Bangladesh rely on pond water for hygiene. Exposure to pond water fecal contamination could therefore still contribute to diarrheal disease despite the installation of numerous tubewells for drinking. The objectives of this study are to determine the predominant sources (human or livestock) of fecal pollution in ponds and examine the association between local population, latrine density, latrine quality and concentrations of fecal bacteria and pathogens in pond water. Forty-three ponds were analyzed for E. coli using culture-based methods and E. coli, Bacteroidales and adenovirus using quantitative PCR. Population and sanitation spatial data were collected and measured against pond fecal contamination. Humans were the dominant source of fecal contamination in 79% of the ponds according to Bacteroidales measurements. Ponds directly receiving latrine effluent had the highest concentrations of fecal indicator bacteria (up to 10⁶ Most Probable Number (MPN) of culturable E. coli per 100 mL). Concentrations of fecal indicator bacteria correlated with population surveyed within a distance of 30-70 m (p<0.05) and total latrines surveyed within 50-70 m (p<0.05). Unsanitary latrines (visible effluent or open pits) within the pond drainage basin were also significantly correlated to fecal indicator concentrations (p<0.05). Water in the vast majority of the surveyed ponds contained unsafe levels of fecal contamination attributable primarily to unsanitary latrines, and to lesser extent, to sanitary latrines and cattle. Since the majority of fecal pollution is derived from human waste, continued use of pond water could help explain the persistence of diarrheal disease in rural South Asia.
  Science of The Total Environment 08/2011; 409(17):3174-82. · 3.29 Impact Factor
• Source

  Available from: Jacob L Mey

  Article: Arsenic exposure and motor function among children in Bangladesh.

  Faruque Parvez, Gail A Wasserman, Pam Factor-Litvak, Xinhua Liu, Vesna Slavkovich, Abu B Siddique, Rebeka Sultana, Ruksana Sultana, Tariqul Islam, Diane Levy, Jacob L Mey, Alexander van Geen, Khalid Khan, Jennie Kline, Habibul Ahsan, Joseph H Graziano
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  ABSTRACT: 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. 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 [β = -3.63; 95% confidence interval (CI): -6.72, -0.54; p < 0.01], FMC (β = -1.68; 95% CI: -3.19, -0.18; p < 0.05), and BC (β = -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 (β = 3.54; 95% CI: 1.10, 6.0; p < 0.01), FMC (β = 1.55; 95% CI: 0.40, 2.70; p < 0.005), and MC (β = 1.57; 95% CI: 0.60, 2.75; p < 0.005) in the unadjusted models. Mn exposure was not significantly associated with motor function. Our research demonstrates an adverse association of As exposure and a protective association of Se on motor function in children.
  Environmental Health Perspectives 07/2011; 119(11):1665-70. · 7.04 Impact Factor
• Source

  Available from: Jacob L Mey

  Article: Manganese exposure from drinking water and children's classroom behavior in Bangladesh.

  Khalid Khan, Pam Factor-Litvak, Gail A Wasserman, Xinhua Liu, Ershad Ahmed, Faruque Parvez, Vesna Slavkovich, Diane Levy, Jacob Mey, Alexander van Geen, Joseph H Graziano
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  ABSTRACT: Evidence of neurological, cognitive, and neuropsychological effects of manganese (Mn) exposure from drinking water (WMn) in children has generated widespread public health concern. At elevated exposures, Mn has been associated with increased levels of externalizing behaviors, including irritability, aggression, and impulsivity. Little is known about potential effects at lower exposures, especially in children. Moreover, little is known regarding potential interactions between exposure to Mn and other metals, especially arsenic (As). We conducted a cross-sectional study of 201 children to investigate associations of Mn and As in tube well water with classroom behavior among elementary school children, 8-11 years of age, in Araihazar, Bangladesh. Data on exposures and behavioral outcomes were collected from the participants at the baseline of an ongoing longitudinal study of child intelligence. Study children were rated by their school teachers on externalizing and internalizing items of classroom behavior using the standardized Child Behavior Checklist-Teacher's Report Form (CBCL-TRF). Log-transformed WMn was positively and significantly associated with TRF internalizing [estimated β = 0.82; 95% confidence interval (CI), 0.08-1.56; p = 0.03], TRF externalizing (estimated β = 2.59; 95% CI, 0.81-4.37; p =0.004), and TRF total scores (estimated β = 3.35; 95% CI, 0.86-5.83; p = 0.008) in models that adjusted for log-transformed water arsenic (WAs) and sociodemographic covariates. We also observed a positive monotonic dose-response relationship between WMn and TRF externalizing and TRF total scores among the participants of the study. We did not find any significant associations between WAs and various scales of TRF scores. These observations reinforce the growing concern regarding the neurotoxicologic effects of WMn in children.
  Environmental Health Perspectives 04/2011; 119(10):1501-6. · 7.04 Impact Factor
• Source

  Available from: Kazi Matin Ahmed

  Article: Microbes enhance mobility of arsenic in pleistocene aquifer sand from Bangladesh.

  Ratan K Dhar, Yan Zheng, Chad W Saltikov, Kathleen A Radloff, Brian J Mailloux, Kazi M Ahmed, Alexander van Geen
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  ABSTRACT: Dissimilatory metal-reducing bacteria can mobilize As, but few studies have studied such processes in deeper orange-colored Pleistocene sands containing 1-2 mg kg(-1) As that are associated with low-As groundwater in Bangladesh. To address this gap, anaerobic incubations were conducted in replicate over 90 days using natural orange sands initially containing 0.14 mg kg(-1) of 1 M phosphate-extractable As (24 h), >99% as As(V), and 0.8 g kg(-1) of 1.2 M HCl-leachable Fe (1 h at 80 °C), 95% as Fe(III). The sediment was resuspended in artificial groundwater, with or without lactate as a labile carbon source, and inoculated with metal-reducing Shewanella sp. ANA-3. Within 23 days, dissolved As concentrations increased to 17 μg L(-1) with lactate, 97% as As(III), and 2 μg L(-1) without lactate. Phosphate-extractable As concentrations increased 4-fold to 0.6 mg kg(-1) in the same incubations, even without the addition of lactate. Dissolved As levels in controls without Shewanella, both with and without lactate, instead remained <1 μg L(-1). These observations indicate that metal-reducers such as Shewanella can trigger As release to groundwater by converting sedimentary As to a more mobilizable form without the addition of high levels of labile carbon. Such interactions need to be better understood to determine the vulnerability of low-As aquifers from which drinking water is increasingly drawn in Bangladesh.
  Environmental Science & Technology 03/2011; 45(7):2648-54. · 4.80 Impact Factor
• Article: Arsenic and manganese exposure and children's intellectual function.

  Gail A Wasserman, Xinhua Liu, Faruque Parvez, Pam Factor-Litvak, Habibul Ahsan, Diane Levy, Jennie Kline, Alexander van Geen, Jacob Mey, Vesna Slavkovich, Abu B Siddique, Tariqul Islam, Joseph H Graziano
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  ABSTRACT: Recently, epidemiologic studies of developmental neurotoxicology have been challenged to increase focus on co-exposure to multiple toxicants. Earlier reports, including our own work in Bangladesh, have demonstrated independent associations between neurobehavioral function and exposure to both arsenic (As) and manganese (Mn) in school-aged children. Our earlier studies, however, were not designed to examine possible interactive effects of exposure to both As and Mn. To allow investigation of possible synergistic impact of simultaneous exposures, we recruited a new sample of 299 8-11 year old children, stratified by design on As (above and below 10 μg/L) and Mn (above and below 500 μg/L) concentrations of household wells. When adjusted only for each other, both As and Mn in whole blood (BAs; BMn) were significantly negatively related to most WISC-IV subscale scores. With further adjustment for socio-demographic features and ferritin, BMn remained significantly associated with reduced Perceptual Reasoning and Working Memory scores; associations for BAs, and for other subscales, were expectably negative, significantly for Verbal Comprehension. Urinary As (per gram creatinine) was significantly negatively associated with Verbal Comprehension scores, even with adjustment for BMn and other contributors. Mn by As interactions were not significant in adjusted or unadjusted models (all p's>0.25). Findings are consistent with other reports documenting adverse impact of both As and Mn exposure on child developmental outcomes, although associations appear muted at these relatively low exposure levels.
  NeuroToxicology 03/2011; 32(4):450-7. · 3.10 Impact Factor
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  Available from: Kazi Matin Ahmed

  Article: Increase in diarrheal disease associated with arsenic mitigation in Bangladesh.

  Jianyong Wu, Alexander van Geen, Kazi Matin Ahmed, Yasuyuki Akita Jahangir Alam, Patricia J Culligan, Veronica Escamilla, John Feighery, Andrew S Ferguson, Peter Knappett, Brian J Mailloux, Larry D McKay, Marc L Serre, P Kim Streatfield, Mohammad Yunus, Michael Emch
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  ABSTRACT: Millions of households throughout Bangladesh have been exposed to high levels of arsenic (As) causing various deadly diseases by drinking groundwater from shallow tubewells for the past 30 years. Well testing has been the most effective form of mitigation because it has induced massive switching from tubewells that are high (>50 µg/L) in As to neighboring wells that are low in As. A recent study has shown, however, that shallow low-As wells are more likely to be contaminated with the fecal indicator E. coli than shallow high-As wells, suggesting that well switching might lead to an increase in diarrheal disease. Approximately 60,000 episodes of childhood diarrhea were collected monthly by community health workers between 2000 and 2006 in 142 villages of Matlab, Bangladesh. In this cross-sectional study, associations between childhood diarrhea and As levels in tubewell water were evaluated using logistic regression models. Adjusting for wealth, population density, and flood control by multivariate logistic regression, the model indicates an 11% (95% confidence intervals (CIs) of 4-19%) increase in the likelihood of diarrhea in children drinking from shallow wells with 10-50 µg/L As compared to shallow wells with >50 µg/L As. The same model indicates a 26% (95%CI: 9-42%) increase in diarrhea for children drinking from shallow wells with ≤10 µg/L As compared to shallow wells with >50 µg/L As. Children drinking water from shallow low As wells had a higher prevalence of diarrhea than children drinking water from high As wells. This suggests that the health benefits of reducing As exposure may to some extent be countered by an increase in childhood diarrhea.
  PLoS ONE 01/2011; 6(12):e29593. · 4.09 Impact Factor