Environmental Investigation for Mass Lead Poisoning among Children in Industrial Area of Samut Sakhon, Thailand

Background: A girl with blood lead level [BLL] of 166 mcg/dL was admitted in hospital due to status epilepticus. A high level of lead dust and contamination in environment was detected in her living area. All the children in a school that was located around 100 meters from the recycling factory were examined. Among these group of children, the prevalence of high BLL (10 mcg/dL or more) was 44.2% (75 from 165 children). Objective: To find the associations of demographic, risk behaviors, and external or internal environmental factors in children with high BLL (10 mcg/dL or more) who lives in area of industrial community. A second objective is to study the effects of high BLL (15 mcg/dL or more) on IQ level and learning disability [LD] among these children. Materials and Methods: A case control study was conducted with 43 cases of school children (BLL of 10 mcg/dL or more), and 43 children as a control group in same school by matching of classroom and gender with 1:1 matched ratio. The baseline characteristics, behavioral, and environmental risk factors (internal and external), and collected samplings of the household environment were sent to standard laboratory to identify lead contamination and the association among the environmental risk factors with high BLL (10 mcg/dL or more) by multiple logistic regression analysis, and looking for the prevalence of low IQ and LD among children who were detected BLL of 15 mcg/dL or more. Results: The study found statistically significant association between high level of BLL and school duration (more than four academic years) (odds ratio 4.86, 95% CI 1.81 to 13.04, p‑value 0.002), the distance between home and the factory (less than 500 meters) (odds ratio 2.98, 95% CI 1.12 to 7.94, p‑value 0.029), and father’s occupation (odds ratio 2.75, 95% CI 1.03 to 7.37, p‑value 0.044). In the group of children who high BLL (15 mcg/dL or more), the studied found the prevalence of 25% in low IQ, 5% of mental retardation, and 66.7% of LD were detected. Conclusion: This study found positive association of high BLL among children living around the industrial community. The most important factors were related with the duration of living in the place related with lead contamination, father’s occupation, and the distance between the housing and the factory. The prevalence of low IQ and LD among children with BLL of 15 mcg/dL or more was higher than average of Thai children. There is a need for blood lead screening for these children and prompt care and prevention if high blood levels of lead is detected.