The nitrate contamination of private well water in Iowa.

Kross, Burton C.; Hallberg, George R.; Bruner, D. R.; Cherryholmes, Keith; Johnson, J K

doi:10.2105/ajph.83.2.270

Cited by 137 publications

(92 citation statements)

References 12 publications

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“…These well features were associated with elevated nitrate levels in our water samples, a finding which is consistent with findings of other studies that have shown that well depth, diameter, age, and construction type are important indicators of well water contamination (Johnson and Kross, 1990;Kross et al, 1993;US EPA, 1994).…”

Section: Discussionsupporting

confidence: 92%

Are nitrate levels in groundwater stable over time?

Ruckart

Henderson

Black

et al. 2007

J Expo Sci Environ Epidemiol

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Epidemiologists often use a retrospective study design to examine for associations between an exposure and the occurrence of adverse health effects. Several of these studies used this approach to examine for an association between elevated levels of nitrate in drinking water and related health effects such as methemoglobinemia, cancer, neural tube effects, or spontaneous abortions. Often, data on exposures that occurred before these health outcomes were not available. Consequently, researchers use measurements of exposures at the time of the study to represent exposures that occurred before people developed these conditions. An opportunity to examine the stability of nitrate in water occurred during a survey of private water wells in nine Midwestern states. In this survey, water samples from 853 homes with drilled wells were collected in May 1994 and in September 1995 and nitrate-nitrogen (nitrate-N) was measured by the colorimetric cadmium reduction method. Nitrate-N levels from the same well over time were assessed by a mixed-effects analysis of variance. Analysis showed no significant difference in between the initial level and those measured 16 months later. Furthermore, analysis showed that most of the variance in the nitrate concentrations in well water was due to well-to-well variation (89%) rather than to residual error (12%). This observation showed that a single measurement of nitrate in water from drilled wells could represent longer periods of exposure.

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Section: Discussionsupporting

confidence: 92%

Are nitrate levels in groundwater stable over time?

Ruckart

Henderson

Black

et al. 2007

J Expo Sci Environ Epidemiol

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“…Concern with health effects of nitrates consumed in drinking water is far from being totally eliminated in the US. In fact, a startling number of wells throughout the US farm belt have water containing nitrate that exceeds the US Environmental Protection Agency limit of 10 mg /l nitrate -nitogen ( Johnson and Kross, 1990;Kross et al, 1993 ). Of wells in South Dakota, which were not drilled to over 40 m deep, 39% contained nitrate levels that exceeded the EPA limits (Johnson and Kross, 1990 ).…”

Section: Nitrate Exposure In Transylvaniamentioning

confidence: 99%

Exposure methodology and findings for dietary nitrate exposures in children of Transylvania, Romania

Zeman

Vlad²,

Kross

2002

J Expo Sci Environ Epidemiol

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Aims: The primary focus of this exposure assessment work involved developing an exposure model and determining a numerical point estimate of the amount of biologically relevant nitrate / nitrite exposure that occurred for each child in the study. This assessment was done in support of two epidemiological studies. The first study was an epidemiological cohort study ( three cohorts based on nitrate / nitrite exposure ) that explored the relationship between high nitrate / nitrite exposure and neuropsychological development. The second study was a nested case / control study ( cases of methemoglobinemia versus disease -free controls ) that sought to explore the relationship between MHG and various risk factors for the disease. Methods: This work uses both dietary survey and environmental sampling and modeling in order to develop two point estimates of nitrate exposure in milligrams per kilogram per day of nitrite ( the biologically active form of the hemoglobin -oxidizing agent ) for the first 6 months of the child's life ( 2 -months -of -age and 6 -months -of -age point estimates ). Methodologies included proxy interviews of primary caregivers, review of existing medical and environmental sampling and analysis. Results: Exposure to nitrate -nitrogen ( with final calculations converted to the biologically active form of the toxin, nitrite ) was categorized as high, medium, and low as determined from the distribution of the data derived from final exposure calculations at both the 2 -months -of -age point estimate and at the 6 -months -of -age point estimate. These tertiles correspond to !1.5 mg / kg / day nitrite -nitrogen for high -exposure individuals, < 1.5 -!0.1 mg / kg / day for medium -exposure individuals, and < 0.1 mg / kg / day for low -exposure individuals. Analyses illustrate that over 90% of the nitrate exposure occurred through the consumption of liquids ( water ) at the 2 -months -of -age point estimate while at the 6 -months -of -age point estimate, a 10 -fold change in the amount of solid consumables occurred. Conclusions: Final exposure calculations were well differentiated into three tertiles based on a point estimate of average daily intake of nitrite in milligrams per kilogram body weight per day at roughly 2 and 6 months of age. These categories of exposure, based on the exposure model point estimate, correspond well with the exposure estimates as estimated only on the basis of cohort status and their corresponding nitrate / nitrite well water levels. Comparisons of these two sets of data illustrate that following the MHG incident, Cohort II shifted places with Cohort I to become the high -exposure cohort. Further, the predictive ability of the exposure assessment in regard to the outcome of MHG was estimated using a Likelihood Ratio and Pearson's Crosstab analysis. This was performed on the 2 -month -of -age point estimate. Likelihood Ratio and Pearson's chi -square were 39.40 and 33.74, respectively, with a probability of achieving these fits by chance alone of < 0.0001. This indicates clearl...

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“…Gaseous nitrogen can be found in many forms such as N 2 , N 2 O, NO, NO 2 , NH 3 and NH 4 (Comly, 1987;Kross et al, 1993). Although there are many sources of nitrogen (both natural and anthropogenic) that could potentially lead to the pollution of groundwater with nitrates, the anthropogenic sources are really the ones that most often cause the amount of nitrate to rise to a dangerous level (Hallberg & Keeney, 1993).…”

Section: Introductionmentioning

confidence: 99%

Spatial and Temporal Distribution of Nitrate Pollution in Groundwater of Abuja, Nigeria

Dan-Hassan¹,

Olasehinde²,

Amadi³

et al. 2012

IJC

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Groundwater has been recognized as playing a very important role in the development of Abuja, Nigeria's Capital as many households, private and government establishments depends solely on hand-dug wells and boreholes for their daily water needs. Exploitation of groundwater is rather delicate because of its potency to contamination and difficulty to remediate when compared to surface water. The purpose of this paper is to present the occurrence of nitrate in groundwater of Abuja and discuss the implication and sources of the nitrate. High nitrate level in drinking water leads to infant methaemoglobinaemia (blue-baby syndrome), gastric cancer, metabolic disorder and livestock poisoning. A simplified map of nitrate occurrences in Abuja indicates that some areas have nitrate concentration above the WHO and NSDWQ guide limit of 50 mg/l and it is dominant in the rainy season than dry season. The number of people drinking water with nitrate concentration above the permissible level cannot be quantified presently. The sources of nitrate in the groundwater were attributed to bedrock dissolution in the course of groundwater migration and more importantly anthropogenic activities such as on-site sanitation, waste dumpsites and agricultural chemicals. Water treatment by bio-denitrification and nitrate pollution control programs should be introduced at local, state and federal levels in order to educate people on the need to protect groundwater from nitrate pollution caused by agricultural activity and indiscriminate disposal of wastes.Keywords: anthropogenic activity, nitrate pollution, groundwater, Abuja IntroductionThe problem of nitrate pollution in groundwater is a common global phenomenon and has been reported by various authors in many parts of Nigeria (Egboka & Ezeonu, 1990;Uma, 1993;Edet, 2000;Adelana & Olasehinde, 2003;Amadi, 2010). The presence of nitrate in groundwater can be derived from natural and/or anthropogenic sources. The soil/rock-water interactions can result to weathering and enrichment of the groundwater with ammonium ions, since groundwater quality is a function of the chemical composition of the soil/rock through which it passes (Amadi, 2010). The chemistry of groundwater is generally conditioned by the nature of the rock formation through which it flows. The sources and distribution of nitrate in groundwater have been studied in some details in Botswana (Staudt, 2003;Vogel et al., 2004;Schiwiede et al., 2005;Stadler, 2005), Namibia (Heaton, 1984;Wrabel, 2005) and South Africa (Tredoux, 2004;Tredoux et al., 2005). These studies have shown that pollution by anthropogenic activities is the main source of high and variable levels in groundwater. Such activities includes inappropriate on-site sanitation and wastewater treatment, improper sewage sludge drying and disposal, livestock concentration at watering points near boreholes and farming activities by application of nitrogenous fertilizers.

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The nitrate contamination of private well water in Iowa.

Cited by 137 publications

References 12 publications

Are nitrate levels in groundwater stable over time?

Are nitrate levels in groundwater stable over time?

Exposure methodology and findings for dietary nitrate exposures in children of Transylvania, Romania

Spatial and Temporal Distribution of Nitrate Pollution in Groundwater of Abuja, Nigeria

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