Groundwater dynamics and arsenic contamination in Bangladesh

Harvey, Charles F.; Ashfaque, Khandaker N.; Yu, Winston; Badruzzaman, A. B. M.; Ali, Muhammad; Oates, Peter M.; Michael, Holly A.; Neumann, Rebecca B.; Beckie, Roger; Islam, Shafiqul; Ahmed, Mubashir

doi:10.1016/j.chemgeo.2005.11.025

Cited by 282 publications

(211 citation statements)

References 17 publications

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“…Concentrations also can vary substantially across an irrigated region, due partly to the initial distribution of arsenic, the variation in aquifer characteristics, and also to the mixing and cycling of arsenic that occurs with pumping of groundwater and the delivery of irrigation water across canal systems and farm fields [253,[280][281][282]. In some areas, arsenic concentrations are higher in shallow wells than in deeper wells, such that some authors suggest preserving deeper aquifers for use as drinking water supplies, rather than extracting deeper water for use in irrigation [253].…”

Section: Extent Of the Problemmentioning

confidence: 99%

Managing Water and Soils to Achieve Adaptation and Reduce Methane Emissions and Arsenic Contamination in Asian Rice Production

Wichelns

2016

Water

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Rice production is susceptible to damage from the changes in temperature and rainfall patterns, and in the frequency of major storm events that will accompany climate change. Deltaic areas, in which millions of farmers cultivate from one to three crops of rice per year, are susceptible also to the impacts of a rising sea level, submergence during major storm events, and saline intrusion into groundwater and surface water resources. In this paper, I review the current state of knowledge regarding the potential impacts of climate change on rice production and I describe adaptation measures that involve soil and water management. In many areas, farmers will need to modify crop choices, crop calendars, and soil and water management practices as they adapt to climate change. Adaptation measures at the local, regional, and international levels also will be helpful in moderating the potential impacts of climate change on aggregate rice production and on household food security in many countries. Some of the changes in soil and water management and other production practices that will be implemented in response to climate change also will reduce methane generation and release from rice fields. Some of the measures also will reduce the uptake of arsenic in rice plants, thus addressing an important public health issue in portions of South and Southeast Asia. Where feasible, replacing continuously flooded rice production with some form of aerobic rice production, will contribute to achieving adaptation objectives, while also reducing global warming potential and minimizing the risk of negative health impacts due to consumption of arsenic contaminated rice.

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Section: Extent Of the Problemmentioning

confidence: 99%

Managing Water and Soils to Achieve Adaptation and Reduce Methane Emissions and Arsenic Contamination in Asian Rice Production

Wichelns

2016

Water

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“…These factors include sediment mineralogy, well depth, microbial oxidation or reduction of arsenic, competing elemental species for sorption sites, groundwater recharge, groundwater flow path, and presence of fractures in bedrock formations (Ayotte et al, 2006;Ford et al, 2006;Harvey et al, 2006;Smedley and Kinniburgh, 2002;Van Geen et al, 2003;van Geen et al, 2006). These factors are often highly variable between wells and therefore have been difficult to incorporate into models for predicting arsenic concentrations in well water (Ayotte et al, 2006;Van Geen et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Validity of spatial models of arsenic concentrations in private well water

Meliker¹,

AvRuskin²,

Slotnick³

et al. 2008

Environmental Research

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Objective-Arsenic is a pervasive contaminant in underground aquifers worldwide, yet documentation of health effects associated with low-to-moderate concentrations (<100 μg/L) has been stymied by uncertainties in assessing long-term exposure. A critical component of assessing exposure to arsenic in drinking water is the development of models for predicting arsenic concentrations in private well water in the past; however, these models are seldom validated. The objective of this paper is to validate alternative spatial models of arsenic concentrations in private well water in southeastern Michigan. Methods-From 1993−2002 the Michigan Department of EnvironmentalQuality analyzed arsenic concentrations in water from 6,050 private wells. This dataset was used to develop several spatial models of arsenic concentrations in well water: proxy wells based on nearest neighbor relationships, averages across geographic regions, and geostatistically-derived estimates based on spatial correlation and geologic factors. Output from these models was validated using arsenic concentrations measured in 371 private wells from 2003−2006.Results-The geostatisical model and nearest neighbor approach outperformed the models based on geographic averages. The geostatistical model produced the highest degree of correlation using continuous data (Pearson's r=0.61; Spearman's rank ρ=0.46) while the nearest neighbor approach produced the strongest correlation (κ weighted =0.58) using an a priori categorization of arsenic concentrations (<5, 5−9.99, 10−19.99, ≥20 μg/L). When the maximum contaminant level was used as a cut-off in a two-category classification (<10, ≥10 μg/L), the nearest neighbor approach and geostatistical model had similar values for sensitivity (0.62−0.63), specificity (0.80), negative predictive value (0.85), positive predictive value (0.53), and percent agreement (75%).Discussion-This validation study reveals that geostatistical modeling and nearest neighbor approaches are effective spatial models for predicting arsenic concentrations in private well water. Further validation analyses in other regions are necessary to indicate how widely these findings may be generalized.

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“…The Aus and Aman rice varieties are mainly rain-fed crops. However, Boro rice is almost completely groundwater-fed (Ravenscroft et al, 2005) and requires approximately 1 m of water per square meter in Bangladesh (Harvey et al, 2006;Michael and Voss, 2009). …”

Section: Introductionmentioning

confidence: 99%

Modeling the changes in water balance components of the highly irrigated western part of Bangladesh

Rahman

Ahmed

Adnan

et al. 2018

Hydrol. Earth Syst. Sci.

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Abstract. The objectives of the present study were to explore the changes in the water balance components (WBCs) by co-utilizing the discrete wavelet transform (DWT) and different forms of the Mann-Kendall (MK) test and develop a wavelet denoise autoregressive integrated moving average (WD-ARIMA) model for forecasting the WBCs. The results revealed that most of the potential evapotranspiration (P ET ) trends (approximately 73 %) had a decreasing tendency from 1981-1982 to 2012-2013 in the western part of Bangladesh. However, most of the trends (approximately 82 %) were not statistically significant at a 5 % significance level. The actual evapotranspiration (A ET ), annual deficit, and annual surplus also exhibited a similar tendency. The rainfall and temperature exhibited increasing trends. However, the WBCs exhibited an inverse trend, which suggested that the P ET changes associated with temperature changes could not explain the change in the WBCs. Moreover, the 8-year (D3) and 16-year (D4) periodic components were generally responsible for the trends found in the original WBC data for the study area. The actual data was affected by noise, which resulted in the ARIMA model exhibiting an unsatisfactory performance. Therefore, wavelet denoising of the WBC time series was conducted to improve the performance of the ARIMA model. The quality of the denoising time series data was ensured using relevant statistical analysis. The performance of the WD-ARIMA model was assessed using the Nash-Sutcliffe efficiency (NSE) coefficient and coefficient of determination (R 2 ). The WD-ARIMA model exhibited very good performance, which clearly demonstrated the advantages of denoising the time series data for forecasting the WBCs. The validation results of the model revealed that the forecasted values were very close to actual values, with an acceptable mean percentage error. The residuals also followed a normal distribution. The performance and validation results indicated that models can be used for the short-term forecasting of WBCs. Further studies on different combinations of wavelet analysis are required to develop a superior model for the hydrological forecasting in the context of climate change. The findings of this study can be used to improve water resource management in the highly irrigated western part of Bangladesh.

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Groundwater dynamics and arsenic contamination in Bangladesh

Cited by 282 publications

References 17 publications

Managing Water and Soils to Achieve Adaptation and Reduce Methane Emissions and Arsenic Contamination in Asian Rice Production

Managing Water and Soils to Achieve Adaptation and Reduce Methane Emissions and Arsenic Contamination in Asian Rice Production

Validity of spatial models of arsenic concentrations in private well water

Modeling the changes in water balance components of the highly irrigated western part of Bangladesh

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