Blood levels of mercury rising amongst older American women

Using data from the U.S. Centers for Disease Control and Prevention's National Health and Nutrition Examination Survey (NHANES), neuroscience researcher Dan Laks from the University of California, Los Angeles, found that while inorganic mercury was detected in the blood of 2% of women aged 18 to 49 in the 1999-2000 NHANES survey, that level rose to 30% of women by 2005-2006.

It appears that inorganic mercury deposition within the human body is a cumulative process, increasing with age and overall in the population over time. The UCLA study found evidence linking inorganic mercury in the blood to tissues known to be targets for the toxin, such as the liver, the immune system and the pituitary gland. Laks also found a connection between levels of the pituitary hormone lutropin and chronic mercury exposure, which he said might help explain mercury's link to neurodegenerative disease. Inorganic mercury can also accumulate in the brain and stay there for years, according to the news release. All of which suggests a rise in risks for disease associated with mercury in older women.

The findings come on the heels of a widely publicised report, released last week by the US Geological Survey, which found that 25% of fish sampled from US rivers and streams have unsafe levels of mercury.

Environmental sources of mercury include coal-fired electricity plants and contaminated fish, which tend to accumulate the toxin in their tissues. According to the news release, chronic mercury exposure has been linked in studies to a higher risk for autism, mental impairment and neurodegenerative disorders such as Alzheimer's disease.

The findings are published online in the journal Biometals.


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First Published in August 2009

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