More than 1.4 million peoplein New York are suspected to have high level of mercury in their blood. That works out to 25 per cent of the population. This elevated level of mercury is from eating a particular kind of fish. This has been revealed by a study conducted by the city's Health Department.
The survey, conducted among 1,811 adults in 2004, found that one-quarter of women ages 20 to 49 had a blood mercury level at or above five micrograms per liter, while nearly half of Asian women had a blood mercury level at that threshold.
The rates are more pronounced among Asians, women, and higher-income New Yorkers who eat more fish. Two-thirds of foreign-born Chinese women had mercury levels at or above the point at which it must be reported to the state.
Officials discovered people eating fish three or fewer times weekly have, on average, levels of mercury below reportable levels, while readings exceed reportable levels among those eating fish four or more times.
Although the mercury level found in most adults do not pose a health risk but it can be a risk for children under the age of six and women who are pregnant or breast feeding. They might increase the risk of cognitive delays for children whose mothers had very high mercury levels during pregnancy. These risks of neurological damage in fetuses and infants can be passed by the mothers through their bloodstreams during pregnancy or through breast milk.
"It's not bad for the average adult who isn't reproducing," said Daniel Kass, assistant commissioner for environmental surveillance and policy at the Department of Health and Mental Hygiene. "For a brief period of life, during pregnancy, while breast-feeding, it would be best to keep mercury levels down."
Fishes with low mercury counts can be eaten more often. Such fish include tilapia, herring or whiting up to five times per week. Pregnant and breast feeding mothers must completely avoid Chilean sea bass, swordfish or fresh tuna, as they are too high in mercury.
The findings released Monday are from the city's Health and Nutrition Examination Survey -- the first such survey conducted by a U.S. city.
Mercury is released into the atmosphere largely by coal-fired power plants and by solid-waste incinerators. In the form of methyl mercury, it passes into lakes and rivers, where it is absorbed by fish and shellfish.
Kass highlighted that fish has health benefits and that the city was in no way recommending that people stop eating it.