Banyikwa Andrew Toyi
Department of Chemistry, College of Natural and Mathematical Sciences (CNMS), University of Dodoma, Dodoma, United Republic of Tanzania.
Environ Geochem Health. 2025 Aug 28;47(10):417. doi: 10.1007/s10653-025-02696-2.
Fluoride (F⁻) pollution poses a significant public health concern in the regions located in the fluoride belt of Tanzania which includes the Singida Region. Groundwater in this belt contains F⁻ that exceed the World Health Organization's recommended limit of 1.5 mg l. The hydrochemistry, distribution of F, and the non-carcinogenic health risk associated with F⁻ pollution in the fluoride belt of Tanzania remain largely unexplored. This study evaluated the hydrochemistry, F⁻ distribution in groundwater, assessed its regulation by major ions, estimated non-carcinogenic health risks, and examined the water's suitability for drinking and irrigation using 71 samples. The parameters analyzed included pH, electrical conductivity (EC), total hardness (TH), Ca⁺, Mg⁺, Na⁺, K⁺, Cl⁻, SO, HCO⁻, and F⁻. The results indicate that F⁻ pollution is prevalent in the Singida Region, with concentrations ranging from 0.17 to 13.00 mg l. Of the water samples analyzed, 56.34% were within the safe limits, while 43.66% exceeded the threshold. The percentage of water samples with a Hazard Quotient (HQ) > 1 for F⁻ was found to be 61.97% for infants, 60.56% for children, and 39.43% for adults, indicating a potential non-carcinogenic health risk from elevated F⁻ levels in drinking water particularly among infants and children. F exhibited a negative correlation with TH, and positive correlations with Na⁺, pH, and HCO⁻. The assessment of irrigation suitability using indices such as Sodium Adsorption Ratio (SAR), Kelly's Ratio (KR), Sodium Percentage (%Na), and Magnesium Adsorption Ratio (MAR) indicates that the groundwater is generally suitable for irrigation purposes.
在坦桑尼亚氟化物带所在地区，包括辛吉达地区，氟化物（F⁻）污染引发了重大的公共卫生问题。该地带的地下水中所含F⁻超过了世界卫生组织建议的1.5毫克/升的限值。坦桑尼亚氟化物带的水化学性质、F的分布以及与F⁻污染相关的非致癌健康风险在很大程度上仍未得到充分研究。本研究利用71个样本评估了水化学性质、地下水中F⁻的分布，评估了主要离子对其的调控作用，估计了非致癌健康风险，并检验了该水用于饮用和灌溉的适宜性。分析的参数包括pH值、电导率（EC）、总硬度（TH）、Ca⁺、Mg⁺、Na⁺、K⁺、Cl⁻、SO、HCO⁻和F⁻。结果表明，辛吉达地区普遍存在F⁻污染，浓度范围为0.17至13.00毫克/升。在所分析的水样中，56.34%在安全限值内，而43.66%超过了阈值。发现F⁻的危害商（HQ）>1的水样比例在婴儿中为61.97%，在儿童中为60.56%，在成人中为39.43%，这表明饮用水中F⁻水平升高存在潜在的非致癌健康风险，尤其是在婴儿和儿童中。F与TH呈负相关，与Na⁺、pH值和HCO⁻呈正相关。使用钠吸附比（SAR）、凯利比率（KR）、钠百分比（%Na）和镁吸附比（MAR）等指标对灌溉适宜性进行的评估表明，该地下水总体上适合用于灌溉目的。
