Factors related to living environment of children The lead concentration in the soil in Ban Thi was 2980, 23 ± 6092, 84 mg / kg, which was 12 times more likely than that in Tan Long with 263, 46 ± 367, 84 mg / kg (p<0, 05) and 43 times higher than 20 in the Vietnamese standard levels with 70 mg / kg dry soil (table 3.18).