Mercury is a naturally occurring element that is found in air, water, and soil. Mercury exposure at high levels can harm the brain, heart, kidneys, and other system of people of all ages, especially for the unborn babies and young children, which can harm the developing nervous system. This study aims to investigate the total mercury levels in infants' umbilical cord blood, of different regions of China, and analyze its risk factors, and provide a basis to reduce the exposure.
One maternal and child health centers or general hospitals was selected in each district. About 200 pairs of mothers and infants born at term (36–42 weeks of gestation) were recruited from September to December 2008 each hospital. The cord blood was collected, of which the concentration of total mercury was detected. Through the mother's questionnaire survey, we analyzed their exposure to risk factors.
A total of 1323 mother-neonate pairs were included in the study. The arithmetic mean and geometric mean of total mercury in cord blood were 2.26 ± 1.19 μg/L and 1.80 ± 1.93 μg/L; and the different levels among the regions were statistically significant (F = 663.961, P = 0.000). Totally, the cord blood mercury risk factors were high maternal family per capita income (OR = 1.496), pregnancy intake poultry (OR = 1.908), fish (OR = 1.685), shellfish (OR = 2.208), and breast milk (OR = 2.322). The protective factors included the high living floors (OR = 0.703), fruits (OR = 0.689) intake during pregnancy. The related factors in different cities were different.
The regional mercury concentrations are at a lower level in comparison with foreign countries; and it differs among regions. Cord blood mercury concentration is not only affected by the family economic and living conditions, but also by the diet during pregnancy. Factors affecting cord blood mercury varied among cities.