Peter G. McCornick

Groundwater Quality and Its Health Impact: An Assessment of Dental Fluorosis in Rural Inhabitants of the Main Ethiopian Rift

This study aims to assess the link between fluoride content in groundwater and its impact on dental health in rural communities of the Ethiopian Rift. A total of 148 water samples were collected from two drainage basins within the Main Ethiopian Rift (MER). In the Ziway-Shala basin in particular, wells had high fluoride levels (mean: 9.4±10.5mg/L; range: 1.1 to 68 mg/L), with 48 of 50 exceeding the WHO drinking water guideline limit of 1.5mg/L. Total average daily intake of fluoride from drinking groundwater (calculated per weight unit) was also found to be six times higher than the No-Observed-Adverse-Effects-Level (NOAEL) value of 0.06 mg/kg/day. The highest fluoride levels were found in highly-alkaline (pH of 7 to 8.9) groundwater characterized by high salinity; high concentrations of sodium (Na⁺), bicarbonate (HCO₃⁻), and silica (SiO₂); and low concentrations of calcium (Ca²⁺). A progressive Ca²⁺ decrease along the groundwater flow path is associated with an increase of fluoride in the groundwater. The groundwater quality problem is also coupled with the presence of other toxic elements, such as arsenic (As) and uranium (U). The health impact of fluoride was evaluated based on clinical examination of dental fluorosis (DF) among local residents using the Thylstrup and Fejerskov index (TFI). In total, 200 rural inhabitants between the ages of 7 and 40 years old using water from 12 wells of fluoride range of 7.8-18 mg/L were examined. Signs of DF (TF score of ≥ 1) were observed in all individuals. Most of the teeth (52%) recorded TF scores of 5 and 6, followed by TF scores of 3 and 4 (30%), and 8.4% had TF scores of 7 or higher. Sixty percent of the teeth exhibited loss of the outermost enamel. Within the range of fluoride contents, we did not find any correlation between fluoride content and DF. Finally, preliminary data suggest that milk intake has contributed to reducing the severity of DF. The study highlights the apparent positive role of milk on DF, and emphasizes the importance of nutrition in management efforts to mitigate DF in the MER and other parts of the world.

Fluoride Exposure from Groundwater as Reflected by Urinary Fluoride and Children's Dental Fluorosis in the Main Ethiopian Rift Valley

This cross-sectional study explores the relationships between childrens F(-) exposure from drinking groundwater and urinary F(-) concentrations, combined with dental fluorosis (DF) in the Main Ethiopian Rift (MER) Valley. We examined the DF prevalence and severity among 491 children (10 to 15 years old) who are life-long residents of 33 rural communities in which groundwater concentrations of F(-) cover a wide range. A subset of 156 children was selected for urinary F(-) measurements. Our results showed that the mean F(-) concentrations in groundwater were 8.5 ± 4.1 mg/L (range: 1.1-18 mg/L), while those in urine were 12.1±7.3 mg/L (range: 1.1-39.8 mg/L). The prevalence of mild, moderate, and severe DF in childrens teeth was 17%, 29%, and 45%, respectively, and the majority (90%; n=140) of the children had urinary F(-) concentrations above 3 mg/L. Below this level most of the teeth showed mild forms of DF. The exposure-response relationship between F(-) and DF was positive and non-linear, with DF severity tending to level off above a F(-) threshold of ~6 mg/L, most likely due to the fact that at ~6 mg/L the enamel is damaged as much as it can be clinically observed in most children. We also observed differential prevalence (and severity) of DF and urinary concentration, across children exposed to similar F(-) concentrations in water, which highlights the importance of individual-specific factors in addition to the F(-) levels in drinking water. Finally, we investigated urinary F(-) in children from communities where defluoridation remediation was taking place. The lower F(-) concentration measured in urine of this population demonstrates the capacity of the urinary F(-) method as an effective monitoring and evaluation tool for assessing the outcome of successful F(-) mitigation strategy in relatively short time (months) in areas affected with severe fluorosis.

The effect of non-fluoride factors on risk of dental fluorosis: Evidence from rural populations of the Main Ethiopian Rift

Elevated level of fluoride (F(-)) in drinking water is a well-recognized risk factor of dental fluorosis (DF). While considering optimization of region-specific standards for F(-), it is reasonable, however, to consider how local diet, water sourcing practices, and non-F(-) elements in water may be related to health outcomes. In this study, we hypothesized that non-F(-) elements in groundwater and lifestyle and demographic characteristics may be independent predictors or modifiers of the effects of F(-) on teeth. Dental examinations were conducted among 1094 inhabitants from 399 randomly-selected households of 20 rural communities of the Ziway-Shala lake basin of the Main Ethiopian Rift. DF severity was evaluated using the Thylstrup-Fejerskov Index (TFI). Household surveys were performed and water samples were collected from community water sources. To consider interrelations between the teeth within individual (in terms of DF severity) and between F(-) and non-F(-) elements in groundwater, the statistical methods of regression analysis, mixed models, and principal component analysis were used. About 90% of study participants consumed water from wells with F(-) levels above the WHO recommended standard of 1.5mg/l. More than 62% of the study population had DF. F(-) levels were a major factor associated with DF. Age, sex, and milk consumption (both cows and breastfed) were also statistically significantly (p<0.05) associated with DF severity; these associations appear both independently and as modifiers of those identified between F(-) concentration and DF severity. Among 35 examined elements in groundwater, Ca, Al, Cu, and Rb were found to be significantly correlated with dental health outcomes among the residents exposed to water with excessive F(-) concentrations. Quantitative estimates obtained in our study can be used to explore new water treatment strategies, water safety and quality regulations, and lifestyle recommendations which may be more appropriate for this highly populated region.

Implications of Drought and Water Regulation in the Krishna Basin, India

The multi-state Krishna river basin (258 948 km2) serving a population of 70 million is an important basin in peninsular India. The over-exploitation in the basin has led to an increase in hydrological droughts and interstate conflicts. During the last five years drought, domestic and energy water needs were met at the expense of agriculture. In the lower reaches, even the domestic water needs could not be satisfied and required coordination with the upstream projects. The over-exploited basin needs integrated management, together with a proper assessment of water allocation criteria.

On target for people and planet: setting and achieving water-related sustainable development goals

Follow this and additional works at: http://digitalcommons.unl.edu/wffdocs Part of the Environmental Health and Protection Commons, Environmental Monitoring Commons, Hydraulic Engineering Commons, Hydrology Commons, Natural Resource Economics Commons, Natural Resources and Conservation Commons, Natural Resources Management and Policy Commons, Sustainability Commons, and the Water Resource Management Commons

Tackling change: future-proofing water, agriculture, and food security in an era of climate uncertainty

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Projections of irrigation water demand in India: What do recent trends suggest?

Abstract Projected increases in irrigation water demand required to feed Indias population have been a significant component of the justification for the ambitious and highly contentious Indias National River Linking Project (NRLP), which, in its ultimate form, seeks to transfer water from relatively water‐rich basins to those basins where demand has already outstripped supply. This paper re‐examines some of the key assumptions underlying the irrigation demand estimations of the NRLP project, and concludes that a number of key assumptions are not consistent with recent trends. Major changes from earlier projections include rapidly changing consumption patterns and the dominance of groundwater as the source of irrigation water choice where available. The major challenge facing the agricultural water sector in India today and over the long term therefore is how to increase the groundwater stock (supply enhancement) to arrest declining groundwater tables, and how to sustain water use by minimizing uncontrolled groundwater pumping (demand management). While large‐scale water developments, including inter‐basin transfers, are likely still necessary, the characteristics of agricultural water demand and realities of available supplies need to be carefully reconsidered.

Beyond 'More Crop per Drop'

This report aims to provide key highlights from two decades of IWMI research and the broader irrigation literature on agricultural water productivity, with an emphasis on the evolution and application of the concept, highlighting its contributions and limitations while identifying opportunities for further refinements in the way it is understood and applied. Chapter two describes the origins of the concept of agricultural water productivity and its methodological developments. Chapter three illustrates the different ways the concept has been operationalized in applied research, offers a description of the pathways—with their associated interventions, for improving water productivity, and discusses the contributions to broader development objectives. Based on these, and considering the broader literature, Chapter four presents a set of key lessons and insights from two decades of research on water productivity. Chapter five concludes by highlighting how a focus on agricultural water productivity has brought greater attention to critical water scarcity and management issues. Important strategic opportunities remain, however, for continued improvements in technologies and management practices, data sources, and interdisciplinary research to develop and apply more comprehensive approaches to address water scarcity concerns and, ultimately, make progress towards broader development objectives.

Adapting to Climate Variability and Change in India

Responding to rainfall variability has always been one of the most critical risks facing farmers. It is also an integral part of the job of water managers, whether it be designing interventions for flood management, improving the reliability of water supply for irrigation or advising on priorities during drought conditions. The conventional tools and approaches employed are no longer sufficient to manage the increasing uncertainty and incidence of extreme climate events, and the consequent effects these have on human vulnerability and food security. To be effective, the technological advances need to be matched with physical, institutional and management innovations that transcend sectors, and place adaptation and responsiveness to variability at the centre of the approach. This chapter examines a number of these challenges and possible solutions at a range of scales, from ‘climate-smart villages’ to national policy, with a focus on Asia and India, in particular.