Abstract：
Manganese is an essential element but can be neurotoxic if overexposed. Our previous study found that a higher level of manganese in nail biomarkers from children living near coal ash storage sites was associated with poorer neurobehavioral function. Children living near this type of pollution may be exposed to other metal neurotoxicants and a better understanding of manganese in the context of multiple exposures is needed. Mixture analyses were completed using nail samples from 251 children aged 6-14 years old. These biomarkers containing metals known to impact brain functioning were investigated to test our hypothesis that a mixture of metals including manganese impacts the development of children living near coal ash sites. Nails collected from children were analyzed using ICP-MS for manganese, arsenic, cadmium, lead, and zinc based on previous research on neurotoxicity. Bayesian kernel machine regression (BKMR) was used while adjusting for age, sex, and maternal education as potential covariates. Children also completed the Behavioral Assessment Research System (BARS) to provide neurobehavioral measures of attention and processing speed as outcomes for mixture analyses. Metal mixture analyses indicated that the relationship of manganese concentration and attention and processing speed was moderated by arsenic.,. When nail biomarkers for arsenic were highest (90th percentile), manganese was associated with poorer neurobehavioral performance on the BARS, measured by CPT hit latency. At low levels of arsenic (10th percentile), there was no evidence of harmful effects from overexposure to manganese on CPT hit latency based on BKMR analysis. Previously reported effects of manganese on neurobehavioral function may be moderated by arsenic exposure. Metal exposures and behavior outcomes can be studied with mixture analyses such as BKMR to evaluate effects of simultaneous exposures on children exposed to pollution.
摘要：
锰是一种必需元素，但如果过度暴露，可能会有神经毒性。我们先前的研究发现，生活在粉煤灰储存地点附近的儿童的指甲生物标志物中锰含量较高与神经行为功能较差有关。生活在这种污染附近的儿童可能会接触其他金属神经毒物，因此需要在多次接触的情况下更好地了解锰。使用来自251名6-14岁儿童的指甲样品完成混合物分析。研究了这些含有已知会影响大脑功能的金属的生物标志物，以检验我们的假设，即包括锰在内的金属混合物会影响生活在粉煤灰附近的儿童的发育。从儿童身上收集的指甲使用ICP-MS分析锰，砷,镉,铅,和锌基于先前对神经毒性的研究。在调整年龄的同时使用贝叶斯核机回归(BKMR)，性别,和母亲教育作为潜在的协变量。儿童还完成了行为评估研究系统（BARS），以提供注意力和处理速度的神经行为测量，作为混合物分析的结果。金属混合物分析表明，砷调节了锰浓度与注意力和处理速度的关系。,.当砷的指甲生物标志物最高时（第90百分位数），锰与BARS上较差的神经行为表现有关，通过CPT命中延迟来衡量。在低砷含量（第10百分位数），根据BKMR分析,没有证据表明锰过度暴露对CPT命中潜伏期有有害影响.先前报道的锰对神经行为功能的影响可以通过砷暴露来调节。可以通过BKMR等混合分析来研究金属暴露和行为结果，以评估同时暴露对暴露于污染的儿童的影响。
