Background

Artisanal and small-scale gold mining (ASGM) is associated with release of neurotoxic metallic or metalloid chemical elements including lead (Pb), mercury (Hg), cadmium (Cd) and arsenic (As).

Objective

To examine associations between prenatal exposure and co-exposure to total lead (T-Pb), total mercury (T-Hg), total cadmium (T-Cd) and total arsenic (T-As) and infant neurodevelopment at 6 to 12 months of age in areas with ASGM activities in Tanzania.

Methods

Women in their second trimester of pregnancy who resided in ASGM areas were enrolled from 2015 to 2017 (n = 883). At 6 to 12 months of age, children were assessed with the Malawi Developmental Assessment Tool (MDAT) (n = 439). We measured T-Pb, T-Hg, and T-Cd in maternal dried blood spots and T-As in maternal urines. Poisson regression was used to examine associations between prenatal concentrations of these elements and neurodevelopmental outcomes.

Results

Prenatal T-Hg concentration was associated with global neurodevelopment status (aPR 1.03, CI:1.01–1.04; p < 0.001) and language impairment (aPR 1.05, CI:1.03–1.07; p < 0.001) on the MDAT. When prenatal T-Hg and T-As values were at or above the human biomonitoring reference values (≥95%) of the German Environmental Survey for Human Biomonitoring, that is 0.80 µg/L and 15 µg/L, respectively, the prevalence ratio of global neurodevelopmental impairment was two times higher (aPR 2.1, CI:1.0–4.3; p = 0.034). There was a 40% increase in the prevalence ratio of global neurodevelopmental impairment (aPR 1.4, CI:0.90–2.10, p = 0.027), when prenatal T-Hg was at or above the reference value of 0.80 µg/L and T-Pb was at or above the reference value of 35 µg/L. When prenatal T-Hg was at or above the reference value of 0.80 µg/L and T-As was at or above the reference value of 15 µg/L, the prevalence ratio of global neurodevelopmental impairment was two times higher (aPR 2.1, CI:1.0–4.3; p < 0.034).

Discussion

Infants born to women in areas with ASGM activities are at significant risk for neurodevelopmental impairment and this is associated with exposure to higher concentrations of Hg prenatally. Co-exposure to high concentrations of Hg and Pb, or Hg and As appeared to have negative potentiated effects on infants’ neurodevelopment.

中文翻译：

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在坦桑尼亚北部从事小型金矿开采活动的地区，产前暴露和共同暴露于金属或准金属元素对婴儿早期神经发育结局的影响。

背景

手工和小规模金矿开采（ASGM）与释放包括铅（Pb），汞（Hg），镉（Cd）和砷（As）的神经毒性金属或准金属化学元素有关。

目的

在6至12个月时检查产前暴露与共同暴露于总铅（T-Pb），总汞（T-Hg），总镉（T-Cd）和总砷（T-As）和婴儿神经发育之间的关联坦桑尼亚从事手工和小规模采金活动的地区的年龄分布。

方法

Women in their second trimester of pregnancy who resided in ASGM areas were enrolled from 2015 to 2017 (n = 883). At 6 to 12 months of age, children were assessed with the Malawi Developmental Assessment Tool (MDAT) (n = 439). We measured T-Pb, T-Hg, and T-Cd in maternal dried blood spots and T-As in maternal urines. Poisson regression was used to examine associations between prenatal concentrations of these elements and neurodevelopmental outcomes.

Results

产前T-Hg浓度与MDAT上的整体神经发育状态（aPR 1.03，CI：1.01-1.04; p <0.001）和语言障碍（aPR 1.05，CI：1.03-1.07; p <0.001）相关。当产前T-Hg和T-As值等于或高于德国人体生物监测环境调查的人体生物监测参考值（≥95％）时，患病率分别为0.80 µg / L和15 µg / L。全球神经发育障碍的患病率是后者的两倍（aPR 2.1，CI：1.0-4.3； p = 0.034）。当产前T-Hg达到或高于参考值0.80 µg / L和T-Pb时，全球神经发育障碍的患病率增加40％（aPR 1.4，CI：0.90-2.10，p = 0.027）。等于或高于参考值35 µg / L。当产前T-Hg等于或高于参考值0时。

讨论区

妇女在具有ASGM活动的地区出生的婴儿处于神经发育受损的显着风险中，这与产前暴露于较高浓度的Hg有关。共同暴露于高浓度的Hg和Pb或Hg和As对婴儿的神经发育具有负面的增强作用。