January 19 (HealthDay News) -- Where a woman lives, how much she makes for a living, and her ethnicity may all be linked to the amount of mercury in her blood, a new survey says.

The report, published in the January issue of Environmental Health Perspectives, found women residing in coastal areas in the Northeastern United States had three to four times the risk of exceeding acceptable blood mercury (BHg) concentration levels than women who lived in inland areas of the country. Nearly one in five Northeastern women exceeded this 3.5 micrograms per liter level.

Women of Asian, Native American, Alaskan, Pacific Island and Caribbean descent were also more likely to have elevated BHg levels.

The findings make sense, as certain types of seafood that can contain high levels of mercury would be more available or acceptable to eat in those areas and by those ethnicities, the study authors noted.

Women with annual household incomes exceeding $75,000 also had higher average BHg levels and also ran a greater risk of having elevated BHg levels when compared with women whose households had annual income below $55,000.

The study examined data collected between 1999 and 2004 in the National Health and Nutrition Examination Survey.

The overall proportion of women with high BHg levels over the study period did decline, though. Since the average amount of seafood did not change much during the six-year study, the type of seafood they ate may have.

"The change in the estimated intake of Hg in seafood among women of childbearing age over the course of the study suggests a pattern of more discerning series of choices in the type of fish eaten, without an overall reduction of fish consumption," the authors wrote.

SOURCE: Environmental Health Perspectives, news release, Jan. 12, 2009