Division of Earth and Ocean Sciences, Box 90227, Nicholas School of the Environment, Duke University, Durham, NC 27708, USA.
Environ Int. 2012 Aug;43:37-47. doi: 10.1016/j.envint.2012.03.002. Epub 2012 Apr 6.
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.
本研究旨在评估地下水氟含量与其对埃塞俄比亚裂谷农村社区牙齿健康的影响之间的关系。从埃塞俄比亚裂谷（MER）的两个流域共采集了 148 个水样。特别是在 Ziway-Shala 流域，井水中的氟含量很高（平均值：9.4±10.5mg/L；范围：1.1 至 68mg/L），50 个井水中有 48 个超过了世界卫生组织 1.5mg/L 的饮用水指导限值。还发现，从饮用地下水（按体重单位计算）中摄入的氟的总日平均摄入量是 0.06mg/kg/天的无观察不良效应水平（NOAEL）值的六倍。氟含量最高的是高碱性（pH 值为 7 至 8.9）、高盐度、高浓度的钠（Na⁺）、碳酸氢盐（HCO₃⁻）和硅（SiO₂）以及低浓度的钙（Ca²⁺）的地下水。地下水氟含量的增加与沿地下水流路径的 Ca²⁺逐渐减少有关。地下水质量问题还与其他有毒元素如砷（As）和铀（U）的存在有关。氟化物的健康影响是根据当地居民的牙齿氟斑症（DF）的临床检查来评估的，使用的是 Thylstrup 和 Fejerskov 指数（TFI）。共检查了 12 口井的 200 名年龄在 7 至 40 岁之间、氟含量在 7.8-18mg/L 之间的农村居民。所有个体均出现 DF（TF 评分≥1）的迹象。大多数牙齿（52%）的 TF 评分为 5 和 6，其次是 TF 评分为 3 和 4（30%），8.4%的 TF 评分为 7 或更高。60%的牙齿失去了最外层的牙釉质。在氟含量范围内，我们没有发现氟含量与 DF 之间存在任何相关性。最后，初步数据表明，牛奶的摄入有助于减轻 DF 的严重程度。该研究强调了牛奶对 DF 的明显积极作用，并强调了营养在减轻 MER 和世界其他地区 DF 管理工作中的重要性。
