Objective: To study the effects of environmental exposure to rare earth elements (REEs) on health in children.
Methods: The level of physical growth and development, function of immune system, intelligence were chosen as the health-response indexes of children. Indicators for physical growth and development were measured. IgA, IgG, IgM and complement C3, C4 in blood serum were determined with turbidimeter measure, IgE were determined by chemiluminescence immunoassay (CLIA), lymphocyle subset CD3, CD4, CD8, CD4/CD8 and NK were determined by flowcytometry. Intelligence quotient (IQ) were examined with Drawing A Man Test in the children aged 7-10 years randomly sampled in the area containing rare earth (RE) ore and the control area in Xunwucounty, Jiangxi. Blood REEs were determined by inductively coupled plasma source mass pectrometry (ICP-MS).
Results: All 15 kinds of REEs were detected in each sample, the quantity of blood REEs of the children were lower in exposure group than in control group and in the rare earth area [(2.10 +/- 0.88)ng/g] was 1.73 times as that of the children in the control area [(1.26 +/- 1.35) ng/g]. The difference is significant (P < 0.01). The humoral immunity would be changed in the body of the children exposed to REEs, the quantity of IgM was lower in exposure group than in control group. The measuring result of T lymph subgroup of the children indicates: CD3, CD4, CD4/CD8 changed a lot. The percent of CD3, CD8 were significantly lower and CD4/CD8 was significantly higher in exposure group than in control group. The score of IQ was lower significantly in the exposure group than in the control. The percentage of high IQ decreased, the percentage of low IQ increased. Multiple regression analysis showed the variable of blood REEs in exposure to REEs group or those in the control group were introduced into the Vital capacity, blood pressure and IgM regression model. The distance from home to the RE area and either RE put in home influenced the score of children's IQ.
Conclusion: The children aged 7-10 years in RE ore area may have higher REEs burden in the body, and exposure to REEs could have adverse influences in children.