Paraoccupational And Environmental Mercury Exposure Due To Small Scale Gold Mining In Central Nicaragua: A Cross-Sectional Assessment Of Blood Mercury Levels In Children And Women

Introduction
The aimed to assess paraoccupational and environmental mercury exposure and related factors in population living in gold-mining towns where the amalgamation process either was still used, or had been phased out, and environmental mercury exposure in population living in a downstream community, with the goal of identifying modifiable factors for prevention.

Methods
We assessed mercury exposure in women and children from three selected communities in located in a gold mining region in central Nicaragua. Total mercury in blood (B-Hg) was determined as a marker of exposure. Background information and potential paraoccupational and environmental determinants for mercury exposure in non-miners and gold miners’ family members (women and children) were investigated trough as semi-structured questionnaire. The field work was carried in 2009.

Results
Children and women from the general population in a small-scale artisanal gold mining town, where mercury was used for amalgamation, had elevated B-Hg levels compared to those living in a nearby mining town where mercury has been restricted during the last two decades. In miner's household members amalgam burning at home contributed to elevated B-Hg levels, especially if the burning took place indoors. B-Hg levels in a community downstream the mining area were comparable with levels observed in miner's household members. In the downstream community, but not in the other areas studied, there was a clear correlation between fish consumption and B-Hg levels.

Discussion
Our data suggests that the levels of mercury exposure for children and women can be reduced substantially by simple modifications of burning practices (e.g. amalgam burning in closed vessels at the local electrical mill plant, not at home). This study clearly identifies the downstream community being at a higher risk than the mining community proper. Clearly, there is a need for environmental monitoring of mercury concentrations in sediments and fish far downstream the gold mining areas in Nicaragua.