Abstract: OBJECTIVE: This study was designed to determine the placental cadmium (Cd) levels and the expression of placental metallothionein (MT), and to investigate Cd exposure levels and its effect on neonates who lived in Guiyu, an electronic waste (e-waste) environmental polluted site. METHODS： Among the 152 placentas included in the study, 100 placentas come from pregnant women who lived in Guiyu (Exposed Group), 52 lived in chaonan, located 10 km away from Guiyu and residents had never been exposed to e-waste pollution (Control Group). Placental Cd levels were measured by atomic absorption spectrometry. Presence of placental MT was determined by immunohistochemistry. Information on maternal and neonatal characteristics and exposure conditions were obtained from hospital records and by personal interviews. RESULTS： In the Exposed Group, mean placental Cd was (0.17±0.48) μg/g, higher than Control Groups (0.10±0.11) μg/g,(P<0.01). The high levels of placental Cd were significantly associated with their occupational and environmental exposure to e-waste recycling pollutants. MT staining was positive and very dense in 67.00％(67/100) of cases in Exposed Group compared to 32.69％ (17/52) in Control Group (P≤0.01). CONCLUSION： Exposure to e-waste recycling pollutants increased Cd exposure in neonates, which was accompanied by increased placental MT expression. Our finding of increased placental MT in Guiyu revealed the impact of pollution and the sensitivity of the placenta to Cd exposure in the environment.

Key words: electronic waste, placenta, cadmium, metallothionein