Mercury and polychlorinated biphenyls in Asian market fish: A response to results from mercury biomonitoring in New York City

In 2004, the New York City (NYC) Health and Nutrition Examination Survey measured the highest blood mercury levels in Asian and foreign-born Chinese demographic groups. Fish consumption was the strongest predictor of exposure. The survey did not inquire about consumption of individual species, and subsequent visits to fish markets serving the Asian community suggested that many popular species lack contaminant data. Our objective was to supplement existing information on contaminants in commercial fish by collecting data on species present in markets serving the Asian community.We measured total mercury and the sum of 101 polychlorinated biphenyl (PCB) congeners in 282 individual specimens of 19 species or products from retail fish markets in Chinese neighborhoods in NYC. Species were selected based on their volume in the market, and an absence or insufficiency of national data on mercury levels. PCBs were measured because they are also contaminants of concern. All measurements were made on a wet weight basis on whole fillets (with skin) or products (drained of liquid). Mean mercury levels ranged from below the limit of detection (0.004 μg/g) in tilapia to 0.229 μg/g in tilefish. The highest mercury level (1.150 μg/g) was measured in a tilefish specimen, and mercury levels in tilefish increased with the specimen size. Mean PCB levels ranged from 1 ng/g in red snapper to 98 ng/g in buffalo carp. The highest PCB levels were measured in a buffalo carp (469 ng/g) and a yellow croaker (495 ng/g). Species-specific differences in PCB levels accounted for only 6.3% of total variability, in contrast with 39.2% for mercury.Although we did not measure high mean mercury levels in the species we sampled, frequent consumption of fish with low to moderate levels can also elevate blood mercury. The data we collected can be used to guide fish consumption in Asian communities. However, risk-benefit trade-offs also need to be considered.