Your search found 4 records
1 Podgorski, J.; Berg, M. 2020. Global threat of arsenic in groundwater. Science, 368(6493):845-850. [doi: https://doi.org/10.1126/science.aba1510]
Groundwater ; Arsenic ; Contamination ; Forecasting ; Risk assessment ; Drinking water ; Population ; Public health ; Aquifers ; Models
(Location: IWMI HQ Call no: e-copy only Record No: H049727)
(1.50 MB)
Naturally occurring arsenic in groundwater affects millions of people worldwide. We created a global prediction map of groundwater arsenic exceeding 10 micrograms per liter using a random forest machine-learning model based on 11 geospatial environmental parameters and more than 50,000 aggregated data points of measured groundwater arsenic concentration. Our global prediction map includes known arsenic-affected areas and previously undocumented areas of concern. By combining the global arsenic prediction model with household groundwater-usage statistics, we estimate that 94 million to 220 million people are potentially exposed to high arsenic concentrations in groundwater, the vast majority (94%) being in Asia. Because groundwater is increasingly used to support growing populations and buffer against water scarcity due to changing climate, this work is important to raise awareness, identify areas for safe wells, and help prioritize testing.
2 Alam, Mohammad F.; Villholth, Karen G.; Podgorski, J.. 2021. Human arsenic exposure risk via crop consumption and global trade from groundwater-irrigated areas. Environmental Research Letters, 16(12):124013. [doi: https://doi.org/10.1088/1748-9326/ac34bb]
Arsenic ; Exposure ; Human health ; Health hazards ; Groundwater irrigation ; Irrigated sites ; Crop production ; Rice ; Wheat ; Maize ; International trade ; Datasets
(Location: IWMI HQ Call no: e-copy only Record No: H050905)
https://iopscience.iop.org/article/10.1088/1748-9326/ac34bb/pdf
https://vlibrary.iwmi.org/pdf/H050905.pdf
https://vlibrary.iwmi.org/pdf/H050905.pdf
(13.00 MB) (13.0 MB)
While drinking water is known to create significant health risk in arsenic hazard areas, the role of exposure to arsenic through food intake is less well understood, including the impact of food trade. Using the best available datasets on crop production, irrigation, groundwater arsenic hazard, and international crop trade flows, we estimate that globally 17.2% of irrigated harvested area (or 45.2 million hectares) of 42 main crops are grown in arsenic hazard areas, contributing 19.7% of total irrigated crop production, or 418 million metric tons (MMT) per year of these crops by mass. Two-thirds of this area is dedicated to the major staple crops of rice, wheat, and maize (RWM) and produces 158 MMT per year of RWM, which is 8.0% of the total RWM production and 18% of irrigated production. More than 25% of RWM consumed in the South Asian countries of India, Pakistan, and Bangladesh, where both arsenic hazard and degree of groundwater irrigation are high, originate from arsenic hazard areas. Exposure to arsenic risk from crops also comes from international trade, with 10.6% of rice, 2.4% of wheat, and 4.1% of maize trade flows coming from production in hazard areas. Trade plays a critical role in redistributing risk, with the greatest exposure risk borne by countries with a high dependence on food imports, particularly in the Middle East and small island nations for which all arsenic risk in crops is imported. Intensifying climate variability and population growth may increase reliance on groundwater irrigation, including in arsenic hazard areas. Results show that RWM harvested area could increase by 54.1 million hectares (179% increase over current risk area), predominantly in South and Southeast Asia. This calls for the need to better understand the relative risk of arsenic exposure through food intake, considering the influence of growing trade and increased groundwater reliance for crop production.
3 Ali, W.; Zhang, H.; Mao, K.; Shafeeque, Muhammad; Aslam, M. W.; Yang, X.; Zhong, L.; Feng, X.; Podgorski, J.. 2022. Chromium contamination in paddy soil-rice systems and associated human health risks in Pakistan. Science of the Total Environment, 826:153910. [doi: https://doi.org/10.1016/j.scitotenv.2022.153910]
Chromium ; Contamination ; Paddy soils ; Rice fields ; Human health ; Health hazards ; Risk assessment ; Metals ; Physicochemical properties ; Bioaccumulation factor ; Translocation ; Modelling / Pakistan / Sindh / Punjab
(Location: IWMI HQ Call no: e-copy only Record No: H051385)
(1.81 MB)
Chromium (Cr) contamination in paddy soil-rice systems threatens human health through the food chain. This study used a new dataset of 500 paddy soil and plant tissue samples collected in the rice-growing regions of Sindh and Punjab Provinces of Pakistan. Overall, 97.4% of grain samples exceeded the Cr threshold values of 1.0 mg kg-1, determined by the China National Food Standard (CNFS). The Cr in paddy soil, 62.6% samples exceeding the China natural background threshold value (90 mg kg-1) for Cr concentration in paddy soil, and lower than the (pH-dependant > 7.5 threshold value for Cr 350 mg kg-1) as determined by China Environmental Quality Standards (EQSs) for paddy soil (GB15618-2018). Geographically weighted regression (GWR) modelling showed spatially nonstationary correlations, confirming the heterogeneous relationship between dependent (rice grain Cr) and independent paddy soil (pH, SOM, and paddy soil Cr) and plant tissue variables (shoot Cr and root Cr) throughout the study area. The GWR model was then used to determine the critical threshold (CT) for the measured Cr concentrations in the paddy soil system. Overall, 38.4% of paddy soil samples exceeding CT values confirm that the paddy soil Cr risk prevails in the study area. Furthermore, the GWR model was applied to assess the loading capacity (LC), the difference between the CT, and the actual concentration of Cr in paddy soil. Loading capacity identified potential paddy soil Cr pollution risk to rice grain and assessed the risk areas. Overall LC% of samples paddy soil Cr risk areas grade: low-risk grade I (34.6%); moderate-risk grade II (15.8%); high-risk grade III (11.2%); and very high-risk grade IV (38.4%) have been assessed in the study area.
The human health index, total hazard quotient (THQ « 1), indicates no potential health risk originating from Cr exposure to the population. However, the excess Cr level in paddy soil and rice grain is still a concern. The current study's results are also valuable for the national decision-making process regarding Cr contamination in the paddy soil-rice system.
The human health index, total hazard quotient (THQ « 1), indicates no potential health risk originating from Cr exposure to the population. However, the excess Cr level in paddy soil and rice grain is still a concern. The current study's results are also valuable for the national decision-making process regarding Cr contamination in the paddy soil-rice system.
4 Araya, D.; Podgorski, J.; Kumi, M.; Mainoo, P. A.; Berg, M. 2022. Fluoride contamination of groundwater resources in Ghana: country-wide hazard modeling and estimated population at risk. Water Research, 212:118083. [doi: https://doi.org/10.1016/j.watres.2022.118083]
Groundwater pollution ; Fluorides ; Contamination ; Population ; Public health ; Risk ; Fluorosis ; Drinking water ; Uncertainty ; Modelling / Africa / Ghana
(Location: IWMI HQ Call no: e-copy only Record No: H051362)
https://www.sciencedirect.com/science/article/pii/S004313542200046X/pdfft?md5=f5a0b06c5352c9788f7edfef65b0700e&pid=1-s2.0-S004313542200046X-main.pdf
https://vlibrary.iwmi.org/pdf/H051362.pdf
https://vlibrary.iwmi.org/pdf/H051362.pdf
(11.70 MB) (11.7 MB)
Most people in Ghana have no or only basic access to safely managed water. Especially in rural areas, much of the population relies on groundwater for drinking, which can be contaminated with fluoride and lead to dental fluorosis. Children under the age of two are particularly susceptible to the adverse effects of fluoride and can retain 80–90% of a fluoride dose, compared to 60% in adults. Despite numerous local studies, no spatially continuous picture exists of the fluoride contamination across Ghana, nor is there any estimate of what proportion of the population is potentially exposed to unsafe fluoride levels. Here, we spatially model the probability of fluoride concentrations exceeding 1.0 mg/L in groundwater across Ghana to identify risk areas and estimate the number of children and adults exposed to unsafe fluoride levels in drinking water. We use a set of geospatial predictor variables with random forest modeling and evaluate the model performance through spatial cross-validation. We found that approximately 15% of the area of Ghana, mainly in the northeast, has a high probability of fluoride contamination. The total at-risk population is about 920,000 persons, or 3% of the population, with an estimated 240,000 children (0–9 years) in at-risk areas. In some districts, such as Karaga, Gushiegu, Tamale and Mion, 4 out of 10 children are potentially exposed to fluoride poisoning. Geology and high evapotranspiration are the main drivers of fluoride enrichment in groundwater. Consequently, climate change might put even greater pressure on the area's water resources. Our hazard maps should raise awareness and understanding of geogenic fluoride contamination in Ghana and can advise decision making at local levels to avoid or mitigate fluoride-related risks.
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