The Society of Environmental Journalists (SEJ) partnered with researchers from the Harvard School of Public Health’s (HSPH) Program on Water and Health (PWH), and Penn Future to study biomarkers of environmental exposure to methyl mercury (MeHg). The overarching goals of the study were to raise awareness and generate discussion among SEJ members about sources of environmental Hg pollution; routes of human exposure to MeHg and potential adverse health effects; and techniques for assessing MeHg exposure. The study also presented an opportunity for attendees of the SEJ October 2004 conference to obtain a biomarker estimate of their recent personal exposure to MeHg, and to identify the patterns of behavior that best explain MeHg exposure among study participants.
The results of the study were somewhat unexpected:
- More than 27% of 260 conference attendees who volunteered hair
samples had concentrations that exceeded the U.S. EPA recommended
- The median mercury concentration was 0.5 parts per million (ppm).
- The highest level discovered was 10.2 ppm.
EPA considers concentrations less than 1 ppm in the hair a low
risk for adverse health effects. From analyzing self-reported diet
surveys, the study’s authors say that the number of fish meals consumed
in the prior month was the strongest predictor of mercury levels in the
hair. John Spengler of the Harvard School of Public Health performed
the study and found that his own mercury level was 3.4 ppm, more than
three times the EPA limit.
A follow-up “high-end” fish consumer study found that people
who substantially reduced their consumption of fish containing moderate
to high Hg levels were able to decrease their Hg biomarker levels to
below the RfD-level within 41 weeks of altering their diet (in that
case, Hg in blood was the biomarker measured).
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Related EVISA News (newest first)
March 1, 2012: High levels of mercury in newborns likely from mothers eating contaminated fish
February 9, 2006: Study show high levels of mercury in women related to fish consumption
last time modified: June 18, 2020