Risk factors for mercury exposure of children in a rural mining town in northern Chile

Objective: Traditional gold mining is associated with mercury exposure. Especially vulnerable to its neurotoxic effects is the developing nervous system of a child. We aimed to investigate risk factors of mercury exposure among children in a rural mining town in Chile. Methods: Using a validated questionnaire distributed to the parents of the children, a priori mercury risk factors, potential exposure pathways and demographics of the children were obtained. Mercury levels were measured through analyzing fingernail samples. Logistic regression modeling the effect of risk factors on mercury levels above the 75^th percentile were made, adjusted for potential confounders. Results: The 288 children had a mean age of 9.6 years (SD = 1.9). The mean mercury level in the study population was 0.13 mg/g (SD 0.11, median 0.10, range 0.001-0.86 μg/g). The strongest risk factor for children's odds of high mercury levels (>75th percentile, 0.165 μg/g) was to play inside a house where a family member worked with mercury (OR adjusted 3.49 95% CI 1.23-9.89). Additionally, children whose parents worked in industrial gold mining had higher odds of high mercury levels than children whose parents worked in industrial copper mining or outside mining activities. Conclusion: Mercury exposure through small-scale gold mining might affect children in their home environments. These results may further help to convince the local population of banning mercury burning inside the households.