Selenium status and hair mercury levels in riverine children from Rondônia, Amazonia

Riverine communities in Rondônia State are exposed to high selenium (Se) content in their diet because of the high-selenium soils identified in the Amazon. However, the Amazonian population has a high mercury (Hg) exposure because this metal accumulates in the soil. Because children are more vulnerable to Hg toxicity, the aim of this study was to evaluate and correlate Se status and hair Hg levels in riverine children (aged 3-9 y) living in two different locations in Rondônia State: Demarcação area (DA) and Gleba do Rio Preto (GRP).

Se levels were assessed using hydride generation quartz tube atomic absorption spectroscopy; total hair Hg levels were assessed using cold vapor atomic absorption spectrometry. Dietary intake was evaluated through a 24-h food record and a food frequency questionnaire.

Forty-two children participated in this study. Eighty-four percent of the children from DA showed low plasma Se. Conversely, all children from GRP presented plasma Se levels above the reference values. Forty-five percent of the children from DA presented low erythrocyte levels, and 55% of the children from GRP showed concentration in erythrocyte above the reference values. The mean Se intake was 41.8 μg/d in DA and 179.0 μg/d in GRP. High hair Hg levels were observed in children from both the DA and GRP (3.57 ± 1.86 and 6.24 ± 5.89, respectively).

Children from both riverine communities are likely to present altered Se status according to their dietary intake. Additionally, these children are highly exposed to Hg, mainly through fish consumption, and the toxicity of this metal may cause metabolic damage.