Effects of Thulium Exposure on IQ of Children

Objective To study the effects of environmental exposure to rare earth elements REEs on intelligence of children. Methods Intelligence quotient IQ were examined with Drawing a Man Test in 464 children aged 7-10 years living in RE ore containing area and the control area in Xunwu country Jiangxi province China. Fifteen kinds of REEs in 112 blood samples 69 samples from RE ore area and 43 samples from the control area  were detected by inductively coupled plasma source mass spectrometry ICP-MS. Results All 15 kinds of REEs were detected in each sample the content of blood REEs of the children in the rare earth area 2.18±1.08 ng/g was 1.73 times of that of the children in the control area 1.26±0.35 ng/g the difference was significant P0.01. The score of IQ in the exposure group 82.63±12.16 was significantly lower than that in the control 87.08±15.28 and the percentage of high IQ decreased and the percentage of low IQ increased . Multiple regression analysis showed that the distance from home to the RE ore and piling up RE in house were related to the score of children’s IQ. Conclusion REEs exposure may be related to children’s IQ decreasing.