The effects of the exposure to neurotoxic elements on Italian schoolchildren behavior

Abstract

Neurodevelopmental disorders are constantly increasing on a global scale. Some elements like heavy metals are known to be neurotoxic. In this cross-sectional study we assessed the neurobehavioral effect of the exposure to trace elements including lead, mercury, cadmium, manganese, arsenic and selenium and their interactions among 299 schoolchildren residing in the heavily polluted Taranto area in Italy. Whole blood, urine and hair were collected for metal analyses, while the Child Behavior Checklist and the Social Responsiveness Scale, administered to the main teacher and the mothers were considered to identify behavioral problems in children. Blood lead mainly influenced social problems, aggressive behavior, externalizing and total problems. Urinary arsenic showed an impact on anxiety and depression, somatic problems, attention problems and rule breaking behavior. A significant interaction between lead and arsenic was observed, with a synergistic effect of the two metals increasing the risk of attention problems, aggressive behavior, externalizing problems and total problems. Overall, we were able to test that higher blood lead, urinary arsenic concentrations and their interaction increase the risk of neurobehavioral problems. This is in line with the U.S. Environmental Protection Agency's priority list of hazardous substances where arsenic and lead are ranked as first and second respectively.

Figure 1

BPb and UAs interaction association with aggressive behavior and attention problems. Association between BPb and UAs interaction and aggressive behavior (first column) and attention problems (second column). In each box the change of the β parameter is represented as a function of BPb (first row) or UAs (second row) concentration. Each line shows how the β coefficient varies across the different levels of the interacting metal (UAs for the first row and BPb for the second row).

Figure 2

BPb and UAs interaction association with total problems. BPb and UAs association with CBCL total problems when an interaction term between the two metal concentrations is included in the linear mixed effects model. Blue color corresponds to low level of Pb or As concentrations while red corresponds to high concentration levels.