Estimation of natural background and source identification of nitrate-nitrogen in groundwater in parts of the Bono, Ahafo and Bono East regions of Ghana

Manu, Evans; Afrifa, George Yamoah; Ansah-Narh, Theophilus; Sam, Frederick; Loh, Yvonne Sena Akosua

doi:10.1016/j.gsd.2021.100696

Cited by 10 publications

(3 citation statements)

References 47 publications

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“…The resulting threshold values were 7 and 4 mg/L NO3 − in groundwater of the Northern and Southern area, respectively. These threshold values were in agreement with the NO3 − threshold calculated for Sardinian groundwater hosted in granitic and metamorphic rocks (Biddau et al, 2017), and similar to present-day background values reported elsewhere (Kim et al, 2015;Carrey et al, 2021;Sarkar et al, 2021;Manu et al, 2022).…”

Section: Nitrate Distribution and Thresholdsupporting

confidence: 91%

Geochemistry, stable isotopes and statistic tools to estimate threshold and source of nitrate in groundwater (Sardinia, Italy)

et al. 2023

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Section: Nitrate Distribution and Thresholdsupporting

confidence: 91%

Geochemistry, stable isotopes and statistic tools to estimate threshold and source of nitrate in groundwater (Sardinia, Italy)

et al. 2023

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“…Nitrogen, one of the most frequent contaminants in freshwaters, is estimated to have a natural occurrence as nitrate (up to 10 mg/L), but values above this threshold reflect anthropogenic pollution [79][80][81][82]. The natural background of nitrate represents only a relative measure due to the interactions between the rock matrix and water, dissolutions, interactions between different water bodies, chemical and biological processes, retention time, and precipitation [82].…”

Section: Nutrients and The Anthropogenic Impact On The Freshwater Sou...mentioning

confidence: 99%

The Interplay of Environment and Biota in Assessing the Freshwater Quality in Karst

Borda

Cociuba

Epure³

et al. 2022

Diversity

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Karst aquifers are both a valuable resource for humankind and a habitat for unique biota. The quality of freshwater sources may be easily affected by natural (e.g., geology, climate, and vegetation) and anthropogenic (e.g., agriculture, livestock, and tourism) changes, particularly in karst landscapes with highly vulnerable groundwater reservoirs. We seasonally monitored nine representative freshwater sources (i.e., six springs, a well, a surface stream, and a cave stream resurgence) in the karst system of the Runcuri Plateau (KSRP) (Western Romanian Carpathians) during seven sampling campaigns in 2019–2021. We assessed how these natural and anthropogenic factors influenced the water quality based on the European and national standards for drinking water. The geological structure (i.e., tectonics and lithology) of the KSRP was reassessed, and the environmental variables of the freshwater sites were investigated in order to evaluate their impact on the physicochemical profile, the microbial contamination, and on the meiofauna presence. Multivariate statistics were performed to gain insights into the interplay among all these factors and to evaluate the self-purification capacity of the KSRP for chemical and microbial pollutants. The most relevant drivers shaping the microbial content of the freshwater sources were the altitude of the sampling sites, the normalized difference vegetation index (NDVI), and air temperature, followed by the physicochemical profile of the waters (i.e., calcium hardness, magnesium hardness, nitrites, nitrates, conductivity, phosphates, total dissolved solids, and iron concentrations). The meiofauna presence was influenced mostly by precipitation, air temperature, and NDVI. Our results reflected the effect of the geological structure and environment on water chemistry and biota assemblages. A pollutant attenuation trend was observed in discharging waters, even though the self-purification capacity of the studied karst system was not statistically supported. More investigations are needed to comprehend the processes developed in the black box of the KSRP.

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“…More recent studies also support these findings. For example, the value of nbl in the area of Rajasthan in India was estimated to be 7.2 mg/L [34], and in the Bono East regions in Ghana, nbl can be expected to be 3.9 mg/L [35]. For the area considered in this paper (a location in Northern Croatia), the Lepeltier method was used to determine nbl values of 8.6 + 2MAD (median absolute deviation) and 8.7 + 2SD (standard deviation) mg/L; thus, the upper limits of the assessment were estimated to be 18.2 mg/L and 24.3 mg/L, respectively [36].…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Distance between the Measured and Assumed Location of a Point Source of Pollution in Groundwater as a Function of the Variance of the Estimation Error

Kovač,

Šrajbek,

Klišanin

et al. 2023

Hydrology

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The localization of pollution sources is one of the main tasks in environmental engineering. For this paper, models of spatial distribution of nitrate concentration in groundwater were created, and the point of highest concentration was determined. This point represents the assumed location of the pollution source and differs from the actual location, so there is a certain distance between the measured and assumed location. This paper puts forward a new hypothesis that the distance between the measured and the assumed location is a function of the variance of the estimation error. The scientific contribution of this paper is based on the fact that the interaction of statistical and geostatistical methods can locate the dominant point source of pollution or narrow down the search area. The above hypothesis is confirmed by the example of the Varaždin wellfield, which was closed due to an excessively high groundwater nitrate concentration. Seven different interpolation methods were used to create spatial distribution models. Each method provides a different model, a different variance of the estimation error, and estimates of the location of the pollution source. The smallest value of variance of the estimation error of 1.65 was obtained for the minimum curvature interpolation method and the largest value of variance (24.49) was obtained for the kriging with logarithmic variogram. Our results show a nonlinear and monotonic relationship between the distance and the variance of the estimation error, so logarithmic and rational quadratic models were fitted to the scatter point data. The models were linearized, a t-test was performed, and the results show that the models can be considered reliable, which is confirmed by the values of the coefficients of determination of the linearized models, which are around 0.50. The obtained results can be used in planning additional research work to determine the measured location of the pollution source. The research methodology we used is universal and can be applied to other locations where high concentrations of certain contaminants have been detected in groundwater in alluvial aquifers.

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Estimation of natural background and source identification of nitrate-nitrogen in groundwater in parts of the Bono, Ahafo and Bono East regions of Ghana

Cited by 10 publications

References 47 publications

Geochemistry, stable isotopes and statistic tools to estimate threshold and source of nitrate in groundwater (Sardinia, Italy)

Geochemistry, stable isotopes and statistic tools to estimate threshold and source of nitrate in groundwater (Sardinia, Italy)

The Interplay of Environment and Biota in Assessing the Freshwater Quality in Karst

Analysis of the Distance between the Measured and Assumed Location of a Point Source of Pollution in Groundwater as a Function of the Variance of the Estimation Error

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