Blood total mercury and fish consumption in the Korean general population in KNHANES III, 2005

The objective of this study was to assess the association between the blood total mercury concentration and fish consumption in the Korean general adult population using a representative sample.

We studied the blood mercury concentration in a representative sample of 1,749 Koreans who were included in the Third Korean National Health and Nutritional Examination Survey (KNHANES III) performed in 2005, and compared it with the frequency of fish consumption collected during the nutrition survey of KNHANES III.

The geometric means of the blood mercury levels in female subjects (n=890), male subjects (n=859), and all participants (n=1,749) representing adult Koreans aged > or =20 years were 3.70 microg/L [95% confidence interval (CI), 3.46-3.94 microg/L], 4.70 microg/L (95% CI, 4.38-5.02 microg/L), and 4.15 microg/L (95% CI, 3.93-4.38 microg/L), respectively. The geometric mean of the blood mercury level was significantly higher in the high-fish-consumption group (4.38 microg/L; more than once a week) than in the low-consumption group (3.71 microg/L: less than once a week), but the intergroup difference of 18% was less than that in Western countries. Among the nine listed individual types of fish and shellfish, there was a general trend for the blood mercury level to increase with the consumption frequency of squid, clam, salted seafood, and mackerel. The proportion of Korean women aged 20-49 years having blood mercury levels of at least 5.8 microg/L was 27.7% (150/542) in our study.

The blood mercury level in a representative sample of the Korean adult population was found to be associated with fish consumption in both men and women. However, a high consumption of fish increased the blood mercury level by only 18%.