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Although environmental lead levels are not significantly elevated, they still pose a serious risk to children, especially those living near mining sites. Lead is a pervasive toxic substance that can impair children's neurocognitive and behavioral development, even at doses traditionally considered safe. The present paper aims to evaluate the associations between lead levels in children's hair (chronic exposure) and their cognitive and behavioral performance (memory, attention, and intelligence skills). A total of 246 children aged from 6 to 11 years old, including 136 healthy controls and 110 children living in a mining area, were enrolled in the current case study.
We used the Digit Span Test (DST), Bell Dam Test (BDT), and Color Progressive Matrix of Raven (CPMR) for the assessment of their memory, attentional, and intelligence skills, respectively. Interviews with parents were conducted to identify co-variables related to Pb exposure. The determination of hair Pb content in the environment was performed by ICP-MS.
Our findings reveal that 35% of the participants have lead-contaminated hair. Notably, girls account for the majority of these cases (41.5%), with a statistically significant association (p = 0.005). Indeed, the distribution of lead (Pb) concentrations in hair by gender shows that girls have a significantly higher mean level (4.07 ± 5.55 μg/g) compared to boys (3.57 ± 14.41 μg/g). The results demonstrated an association between Pb exposure and the predicted outcome of impaired visual attention (OR=1.660) and impaired short-term memory (OR=1.091). In light of these results, we conclude that exposure to lead contamination constitutes a risk factor for the impairment of children's cognitive abilities, particularly visuo-spatial attention and short-term verbal memory. Recommendations are issued to reduce environmental exposure to Pb and to promote the implementation of cognitive remediation actions.
Keywords: Lead, Hair, Memory, Attention, Intelligence, Children
