Background

In the state of Hidalgo, Mexico, is found the largest second deposit of Manganese (Mn) in Latin America. Various studies on the sources of emission, exposure, and the effects on the health of children and adults have been conducted utilizing an ecosystem approach. Given the findings of Mn levels in air and the neurocognitive effects, an Environmental Management Program (EMP) was designed and implemented with the purpose of reducing exposure to Mn of the population, including various actions for reducing Mn emissions into the atmosphere.

Objective

To evaluate the impact of the EMP on the concentrations of Mn in air, as well as the modification of exposure to Mn in the blood and hair of adult residents of the communities intervened.

Methods

A quasi-experimental study was conducted in five rural communities, in which Mn concentrations were evaluated in air and in blood in the years 2002 and 2007, pre-intervention, and in 2013, postintervention. In 2003, the concentration of hair Mn among the communities was evaluated. Measurements were carried out of Particulate Matter (PM) of >10 and 2.5 μm (PM10 and PM2.5), and Mn in PM10 and PM2.5 were measured using proton-induced X-ray emissions (PIXE). The method of Difference in Differences (DID) was applied to estimate the impact of EMP on Mn concentrations in particulate matter via linear regression through multilevel models. To evaluate the effect of Mn concentrations in air over Mn concentrations in blood in both study periods in the mining communities per year (2002 and 2013), a linear regression model for each year was employed.

Results

We estimated that the EMP contributed to reducing the average daily concentrations of Mn in PM10 and PM2.5 by 92 and 85%, respectively. The adjusted model did not show an effect of Mn concentrations in air over Mn concentrations in blood in both study periods.

Conclusions

The results suggest that the measures implemented to reduce Mn emissions in air exerted a significant impact on the reduction of inhaled exposure in adult population.

中文翻译：

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评估环境管理计划对墨西哥矿区锰暴露的影响

背景

在墨西哥的伊达尔戈州，发现了拉丁美洲第二大的锰（Mn）矿床。利用生态系统方法对排放源，暴露源以及对儿童和成人健康的影响进行了各种研究。考虑到空气中锰水平的发现和神经认知作用，设计并实施了一项环境管理计划（EMP），目的是减少人口对锰的暴露，包括减少向大气中排放Mn的各种行动。

客观的

为了评估EMP对空气中Mn浓度的影响，以及干预社区成年居民血液和头发中Mn暴露量的变化。

方法

在五个农村社区进行了一项准实验研究，在干预前和干预后的2002年和2007年，以及在干预后的2013年，对空气和血液中的Mn浓度进行了评估。2003年，评估了社区中头发Mn的浓度。对> 10和2.5μm的颗粒物（PM）（PM10和PM2.5）进行了测量，并使用质子诱导的X射线发射（PIXE）测量了PM10和PM2.5中的Mn。应用差异法（DID）通过多级模型通过线性回归估算EMP对颗粒物中Mn浓度的影响。为了评估采矿社区每年（2002年和2013年）两个研究期中空气中Mn浓度对血液中Mn浓度的影响，采用了每年的线性回归模型。

结果

我们估计EMP有助于分别将PM10和PM2.5中的Mn平均每日浓度降低92％和85％。在两个研究期间，调整后的模型均未显示空气中Mn浓度超过血液中Mn浓度的影响。

结论

结果表明，为减少空气中的Mn排放而采取的措施对减少成年人口的吸入接触有重大影响。