One quarter of New York City adults have elevated blood mercury levels, and the problem - closely tied to fish consumption - is most acute among Asians, women and higher-income New Yorkers, according to findings released this morning by the city’s Department of Health and Mental Hygiene.
For most adults, the higher levels do not pose a health risk, but children born to mothers with very high mercury levels during pregnancy are at greater risk of cognitive delays.
The city says it is conducting follow-up studies of fish sold in local markets, but in the meantime, has urged pregnant and breastfeeding women to moderate their consumption of mercury-rich fish.
The findings are likely to stir what is already a contentious debate over sushi. On The Times’s Op-Ed page last week, the author Steven A. Shaw argued that alarm over mercury levels in sushi has been vastly overblown and that there is too much empty speculation over food-borne illnesses, while another author, Trevor Corson, contended that the much-hyped depletion of bluefin tuna is not as much of a problem as it is made out to be.
â€No one needs to stop eating fish, but some people may need to change the type and amount they eat,†said Daniel Kass, the Health Department’s assistant commissioner for environmental surveillance and policy. “Young children,
breastfeeding mothers, and women who are pregnant or planning pregnancy should eat fish that are lower in mercury and limit fish that are higher in mercury.â€
Mercury levels remain the same whether a fish is cooked or served raw. “The reason pregnant women should avoid raw fish is not because they're more susceptible to food-borne illness (they're not), but because many antibiotics to treat food-borne illness are contraindicated during pregnancy because of risks to the fetus,†a spokesperson for the Health Department wrote in an e-mail message to The Times.
These are the major findings released by the Health Department:
Among women 20-49 years old in New York City, the average blood mercury level is 2.64 µg/L (micrograms per liter), three times that of similarly-aged women nationally (0.83 µg/L).
Approximately one quarter of New York City women in this age group have a blood mercury level at or above 5 µg/L, the New York State reportable level.
People who eat fish three or fewer times each week have, on average, levels of mercury below the reportable level, while average readings exceed the reportable level among those who eat fish four or more times.
Higher-income New Yorkers have higher mercury levels; New Yorkers in the highest income bracket average 3.6 µg/L, compared to 2.4 µg/L among the lowest income group.
Average blood mercury levels are considerably higher among New York City Asian women (4.1 µg/L); nearly half (45 percent) have blood mercury levels at or above the State reportable level.
Among Asians, foreign-born Chinese women have particularly high levels compared to the rest of New York City. Two thirds (66 percent) have mercury at or above the reportable level.
Foreign-born Chinese New Yorkers eat an average of three fish meals per week, compared to about one among New Yorkers over all. About one quarter of Chinese New Yorkers eat fish five or more times each week, compared to fewer than one in 15 overall.
The Health Department has prepared a brochure in English, Spanish and Chinese that urges New Yorkers to eat fish in moderation and a fact sheet on mercury. High-mercury fish include Chilean sea bass, grouper, king mackerel, marlin, orange roughy, shark, swordfish, tilefish, tuna steaks and sushi grade tuna.