Mercury can be harmful to the developing nervous system. In 2004, the New York City (NYC) Health and Nutrition Examination Survey (HANES) measured the highest blood mercury levels in Asian and foreign-born Chinese New Yorkers. Mercury levels were highest in those who ate fish most often. Most people can eat fish without being concerned about mercury, but pregnant and breastfeeding women and young children should choose fish wisely. The Health Department responded to the NYC HANES findings by measuring mercury and other contaminants in 19 types of fish from retail markets in Chinese neighborhoods in NYC.
On average, mercury in the fish we sampled was not high, but even low to moderate contamination can raise blood mercury levels if fish is eaten very frequently. Polychlorinated biphenyls (PCBs) were another group of contaminants we measured in fish. Levels ranged widely within species, which may be due to varying PCB contamination across bodies of water. Study results have been published in the journal Environmental Research, where more details can be found.
We have also made our source data about contaminant levels in fish publicly available for use by other scientists (download data here). These data can be used to steer fish consumers towards the least contaminated fish. Overall, our advice is to “Eat Fish, Choose Wisely,” in recognition of the health benefits fish offer, and as a reminder that it is important to consider both risks and benefits when choosing what to eat.
For guidance on how to reduce exposure to mercury through fish consumption, you can download the Eat Fish, Choose Wisely brochure.