A benchmark concentration analysis for manganese in drinking water and IQ deficits in children
A benchmark concentration analysis for manganese in drinking water and IQ deficits in children
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DOI：
10.1016/j.envint.2019.05.083
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发表时间：
2019-09-01
影响因子：
11.8
通讯作者：
Bouchard, Maryse F.
中科院分区：
文献类型：
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作者：
Kullar, Savroop S.;Shao, Kan;Bouchard, Maryse F.
背景：锰是一种必需营养素，但过量可能会成为一种强效的神经毒物。我们之前报道了两项针对儿童的横断面研究的结果，表明饮用水中锰浓度较高与智商得分缺陷有关。尽管这种神经毒性金属很常见，但其在饮用水中的浓度很少受到监管。目的：我们的目的是应用基准浓度分析来估计与儿童预先设定的认知障碍水平相关的水锰水平，即表现智商分数下降 1%、2% 和 5%。方法：汇总在加拿大进行的两项研究的数据，得出 630 名儿童（年龄 5.9-13.7 岁）的样本，其中包含自来水锰数据注意力和认知，以及混杂因素。我们使用贝叶斯基准剂量分析系统，基于七种不同的暴露-反应模型，计算水中锰的基准浓度 (BMC) 和可信区间下限 (BMCL) 的权重平均中值估计值。结果：与性能智商得分降低 1% 相关的饮用水中锰的 BMC 为 133 微克/升（BMCL，78 微克/升）；减少2%时，该浓度为266μg/L（BMCL，156μg/L）；减少5%时，该浓度为676μg/L（BMCL，406μg/L）。在性别分层分析中，与男孩智商下降 1%、2% 和 5% 相关的锰浓度分别为 185、375 和 935 μg/L（BMCL，75、153 和 386 μg/L），以及 78、95、192 μg/L（BMCL，9、21 和 74 μg/L）。结论：研究表明，应设定饮用水中锰的最大可接受浓度，以保护儿童（最脆弱的人群）免受锰神经毒性。目前的风险分析可以指导负责制定这些标准的决策者。
Background: Manganese is an essential nutrient, but in excess, can be a potent neurotoxicant. We previously reported findings from two cross-sectional studies on children, showing that higher concentrations of manganese in drinking water were associated with deficits in IQ scores. Despite the common occurrence of this neurotoxic metal, its concentration in drinking water is rarely regulated.Objective: We aimed to apply a benchmark concentration analysis to estimate water manganese levels associated with pre-defined levels of cognitive impairment in children, i.e. drop of 1%, 2% and 5% in Performance IQ scores.Methods: Data from two studies conducted in Canada were pooled resulting in a sample of 630 children (ages 5.9-13.7 years) with data on tap water manganese concentration and cognition, as well as confounders. We used the Bayesian Benchmark Dose Analysis System to compute weight-averaged median estimates for the benchmark concentration (BMC) of manganese in water and the lower bound of the credible interval (BMCL), based on seven different exposure-response models.Results: The BMC for manganese in drinking water associated with a decrease of 1% Performance IQ score was 133 mu g/L (BMCL, 78 mu g/L); for a decrease of 2%, this concentration was 266 mu g/L (BMCL, 156 mu g/L) and for a decrease of 5% it was 676 mu g/L (BMCL, 406 mu g/L). In sex-stratified analyses, the manganese concentrations associated with a decrease of 1%, 2% and 5% Performance IQ in boys were 185, 375 and 935 mu g/L (BMCLs, 75, 153 and 386 mu g/L) and 78, 95, 192 mu g/L (BMCLs, 9, 21 and 74 mu g/L) for girls.Conclusion: Studies suggest that a maximum acceptable concentration for manganese in drinking water should be set to protect children, the most vulnerable population, from manganese neurotoxicity. The present risk analysis can guide decision-makers responsible for developing these standards.