| Background: Guiyu, situated in Shantou, Guangdong province of South China, is a popular e-waste destination, and high levels of heavy metals have been identified in the environmental and human samples. Our previous studies in Guiyu indicate higher levels of lead, cadmium, and manganese, chromium in cord blood samples and blood samples from children. Heavy Metals are the harm to children on brain development. Children are more susceptible to neurotoxicants and chronic heavy metal exposure is associated with deficits in neurobehavioral developmental and function. Significant data gaps exist in evaluating neurodevelopmental effects from exposure mixtures of multiple heavy metals to primitive e-waste recycling. So we conducted this study to measure the current exposure levels of heavy metal lead, cadmium, manganese in Guiyu children 3 to 7 years old and evaluate neurobehavioral development effects and S100βfunction related to exposure to primitive e-waste recycling. Thus, we explored the association between heavy metals exposure and behavior while taking S100βinto account and analyzed the relative strength of the association between blood heavy metal concentrations, serum S100βlevels and behavioral test scores.Objective: To determine the current exposure levels and analysis trend from 2004 to 2009 of lead, cadmium, and manganese from primitive e-waste recycling in preschool children, and to evaluate neurobehavioral effects and S100βfunction related to heavy metal exposure to primitive e-waste recycling.Material and method: We enrolled 240 elementary school children aged 3 to 7 years old who live in Guiyu. Lead, cadmium and manganese in whole blood were measured using Graphite Furnace Atomic Absorption Spectrometry. We used ADHD symptom rating scale as defined by DSM- IV to measure prevalence of neurobehavioral disorder ADHD, the Conners'Rating Scales-Revised (CRS-R) and the Rutter Behavior Questionnaire (RBQ) to evaluate behavior (all in Chinese version). Serum S100βwill be assayed with ELISA methods. Non-parametric analyses were used for data with skewed distributions and chi-square tests were used for categorical data. Spearman correlation analysis was conducted to evaluate the relationship between different parameters.Result:1) The median BPb of children aged 3 to 7 years old in Guiyu was 7.33μg/dL in 2009, and the children with BLL over 10μg/dL, which was considered as high lead burden (HLB), were 16.38%. Compared with 2004, 2006, 2008, both mean BLL and HLB rate in 2009 were significantly lower than others three year studies (P<0.01). The median BCd of children in 2009 was 0.69μg/L. Children blood cadmium levels were increased with the age (P<0.01). The median BMn of children in 2009 was 17.98μg/L. BMn of children aged 3 years and 4 years were higher than children aged 5 years (P<0.05).2) Prevalence of neurobehavioral disorder ADHD was 18.6%, which were significantly higher than the same studies in other regions. Three subtypes were differentiated: predominantly hyperactive (ADHD-PH) was 48.3%, predominantly inattentive (ADHD-I) was 44.8%, and combined (ADHD-C) was 6.9%. Children were suspected to have behavior problems with Rutter parents'scale scores more than 13-point was 45.24%. Children were suspected to have behavior problems with Rutter teacher'scale scores more than 9-point was 46.45%.3) DSM-IV Hyperactive/Impulsive, Conners Impulsivity-Hyperactivity, Rutter antisocial behavior total scores of the teachers'rating scales in high lead group children were significantly higher than low lead group, grouped according to the median BPb. High cadmium group (BCd≥Medium) children had higher scores than low cadmium group (BCd |
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