Mercury exposure assessment in Iranian women's hair of a port town with respect to fish consumption and amalgam fillings

In this study we aimed to estimate the level of mercury in women's hair and its association with fish consumption and amalgam fillings in an Iranian southern port town (named Mahshahr). A total number of 195 hair samples were collected randomly from women aged 25–45 years free from occupational exposures to mercury. Additional information about these women's age, weight, height, number of pregnancies, level of education, number of amalgam fillings and fish consumption were also gathered. The determination of Hg level in hair samples was carried out by the LECO, AMA 254, Advanced Mercury Analyzer, according to ASTM standard No. D-6722. The average mercury level in these women's hair was 2.95 ± 2.33 µg/g (ranged from 0.07 to 24.46 µg/g). In the next stage, the study participants were divided into four groups with respect to their fish consumption and number of amalgam fillings; A) < 3 amalgam fillings, < 3 times fish consumption per month, B) < 3 amalgam fillings, > 7 times fish consumption per month, C) > 6 amalgam fillings, < 3 times fish consumption per month, and D) > 6 amalgam fillings, > 7 times fish consumption per month. Statistical analysis showed that the Hg level was significantly different in these four groups (P < 0.001). Mercury levels in this sample exceeded the USEPA-recommended 1 μg/g in 76.4% of the studied population. Finally, the multiple linear regression results revealed that frequency of fish consumption and amalgam restorations are the most important routes of Hg exposure. However, the main determinant of Hg exposure was the intake of Hg through fish consumption.