Mercury concentration in hair samples from Chinese people in coastal cities

This investigation was made to estimate current normal concentrations of total mercury in the hair of Chinese coastal people. Hair samples were collected from 659 healthy inhabitants in the areas along the coast and the rivers (such as Shanghai, Ningbo, Dalian, Xiamen, and Zhoushan) of China from Feb. 2005 to June 2006. Total mercury concentrations in the samples were analyzed by the cold vapor atomic adsorption spectrometry method (CVAAS). The results showed the geometric mean concentration of total mercury in the hair of the total population (N = 659) was 0.83 microg/g, and the geometric mean of the concentrations of total mercury in the hair of the male (0.94 microg/g, 338 inhabitants with an average age of 35.2, age 2-93) was higher than that of the female (0.72 microg/g, 321 inhabitants with an average age of 39.1, age 1-90). In both the male and female, the mean concentrations of total mercury in hair increased with age, and then gradually decreased. There was a significant correlation between the total hair mercury and the place of residence (p < 0.01), and total hair mercury was the highest in volunteers who lived in Zhoushan. Over half of all sample concentrations were below the USEPA-recommended 1 microg/g. In Zhoushan (males, 2.44 microg/g; females, 1.94 microg/g) and Ningbo (males, 1.06 microg/g; females, 1.02 microg/g), it exceeded the recommended level. Very little females (0.3%) of reproductive age showed hair mercury levels close to 10 microg/g. It was thus concluded that fish consumption was a major current route for mercury exposure in China.