Children’s Exposure to toxic trace elements in the Southern Peruvian Amazon

Abstract

Background: Exposures to toxic elements such as mercury (Hg), arsenic (As), cadmium (Cd) and lead (Pb) adversely effect health and development of children. Scant data exists on children’s exposure to these elements in rapidly developing areas of Low- and Middle-Income Countries, where exposure may pose significant health threats. The Southern Peruvian Amazon of Madre de Dios (MDD) is one such region undergoing rapid changes including highway development, deforestation, agriculture, and artisanal and small-scale gold mining. Prior analysis of adult nails, an uncommon yet advantageous biomarker, revealed elevated exposures to Hg, As, Cd, and Pb among adults. Children’s exposures were not assessed, yet increased activity and nutrient uptake make them a critical sub-population. Objective: To assess prevalence and risk factors for children’s exposures to As, Cd, Pb and Hg in a population-based study in MDD. Methods: Follow-up (2014) of the IMAS (Investigacion de Migracion, Ambiente y Salud) Study collected surveys, nail clippings, and health metrics on members of 310 households in 46 localities across MDD. Nail-element concentrations were analyzed in children under 10 (n=104) using Inductively Coupled Plasma Mass spectrometry. Element correlations were assessed with Spearman coefficients. Associations between nail-element concentrations and demographic, environmental, and dietary factors were tested by t-tests. Results: Median nail-element levels were 247 ng/g (As), 189 ng/g (Cd), 392 ng/g (Hg), and 1144 ng/g (Pb). As-, Cd-, and Pb-nail concentrations were significantly higher in children than adults. Pb was higher in urban compared to rural children. Hg was higher in mining affected areas, while Cd was elevated in non-mining affected areas. Younger (<5 years) children had higher As and Pb exposure (p<0.05) compared to older children. There were no significant sex differences.Conclusions: MDD children are exposed to a mixture of mercury, cadmium, lead and arsenic. Future work should ascertain the public health impact of these exposures.