Variables and research index: - The situation of lead contamination and the physical and mental development status of children + Average of BLLs, BLLs following age, sex, location + Height, weight, chest index, Body Mass Index (BMI), red blood cell and Hemoglobin (Hb) following BLLs + Mental and behavior development index according to Raven, ASQ, DBC-P and Vanderbilt scale following BLLs + BLLs (CDC 2005): <10, from 10 - 45 and > 45µg / dl - Determine some factors related to lead contamination in children in 7 the study areas + Environmental factors: lead concentration in soils, drinking water and air ambiance at study sites + Social demographics and behavior factors of children: age, sex, history of using thuoc cam (a kind of traditional medicine), hand washing habits before meals, outdoor play time and characteristics of play area + Familial factors: parents work at the mine, the distance from home to the mine, the drinking water source used at home, the habit of clothes washing when there are people working at the mine and the knowledge, attitude and practice (KAP) of the father / mother about preventing lead poisoning for children - Evaluate the results of preventive interventions by health education and using of pectin for children + Percentage of KAP of parents before and after intervention + BLLs changing and some symptoms related to chronic lead contamination in children before and after intervention 2.3.3.