Abstract The Kwahu-Bombouaka Group of the Voltaian Basin, which defines the northern fringe of the basin, constitutes a significant part of the North East Region of Ghana. Most of the inhabitants in the region depend on groundwater for domestic and irrigation purposes. Therefore, a geochemical characterization and assessment of groundwater quality in the area was carried out using hydrochemical, GIS-based ordinary kriging interpolation and multivariate statistical methods on fifty-five (55) borehole water samples. The aim of this study was to determine the concentrations and spatial distribution of various ions, groundwater quality issues and the geochemical processes contributing to groundwater chemistry. The area is largely underlain by sandy shales and mudstones of the Poubogou Formation and feldspathic, quartzitic sandstones with conglomeratic lenses of the Panabako Formation. The abundance of major cations in the groundwater is in the order: Na+ > Ca2+ > K+ > Mg2+ whereas that of the major anions vary in the order: HCO3− > SO42− > Cl−. Na–HCO3 water type is common in the area, which may be due to dissolution from silicate minerals (albite and microcline) in the basement rocks. The results indicate that fluoride (0.01–8.40 mg/L, mean of 0.58 mg/L) and boron (0.01–4.81 mg/L, mean of 0.28 mg/L) contamination is a threat to groundwater quality with respect to their guideline values provided by the World Health Organization. The groundwater chemistry is primarily controlled by ion exchange reactions, weathering of silicate minerals residing in the Panabako Formation and anthropogenic activities from agriculture. Groundwater in the area is largely suitable for drinking purposes although some few boreholes in the northwestern and southeastern parts have high fluoride and boron concentrations. The sodium percentage (11–99%, mean of 70%), magnesium ratios (2.05–57, mean of 29) and sodium adsorption ratio (0.15–38, mean of 4.72) are quite high in some of the communities in the southeastern part of the area. This suggests that water in this part of the area is not entirely suitable for irrigation purposes.

中文翻译：

---

加纳沃尔泰超群 Kwahu-Bombouaka 群地下水水质的水文地球化学特征和评价

摘要 沃尔泰盆地北部边缘的夸胡-邦布阿卡群构成了加纳东北地区的重要组成部分。该地区的大多数居民依赖地下水用于生活和灌溉目的。因此，使用水化学、基于 GIS 的普通克里金插值法和多元统计方法对五十五 (55) 个钻孔水样进行了该地区地下水质量的地球化学表征和评估。本研究的目的是确定各种离子的浓度和空间分布、地下水质量问题以及影响地下水化学的地球化学过程。该地区主要由坡布沟组砂质页岩和泥岩以及长石、石英质砂岩，带有 Panabako 组的砾岩透镜体。地下水中主要阳离子的丰度顺序为：Na+ > Ca2+ > K+ > Mg2+ 而主要阴离子的丰度顺序为：HCO3− > SO42− > Cl−。Na-HCO3 水类型在该地区很常见，这可能是由于基岩中硅酸盐矿物（钠长石和微斜长石）的溶解所致。结果表明，氟化物（0.01-8.40 mg/L，平均为 0.58 mg/L）和硼（0.01-4.81 mg/L，平均为 0.28 mg/L）污染对地下水质量相对于其准则值构成威胁由世界卫生组织提供。地下水化学主要受离子交换反应、存在于 Panabako 地层的硅酸盐矿物的风化和农业人为活动的控制。尽管西北部和东南部的一些钻孔中氟化物和硼的浓度很高，但该地区的地下水主要适合饮用。东南部一些社区的钠百分比（11-99%，平均为 70%）、镁比率（2.05-57，平均为 29）和钠吸附率（0.15-38，平均为 4.72）相当高区域的一部分。这表明该地区的水并不完全适合灌溉目的。72) 在该地区东南部的一些社区中相当高。这表明该地区的水并不完全适合灌溉目的。72) 在该地区东南部的一些社区中相当高。这表明该地区的水并不完全适合灌溉目的。