EPA Estimates Mercury Exposure Risk to Newborns
WASHINGTON, D.C. -- February 27, 2004 -- About 630,000 newborns in the United States had unsafe amounts of mercury in their blood derived from contaminated maternal cord blood, according to a recent Environmental Protection Agency (EPA) report. The study suggests that mercury accumulates in umbilical cord blood at a level that is 1.7 times higher than that in the blood of the mother. This means that a woman whose mercury blood level is about 3.5 parts per billion could have a newborn with a mercury concentration greater than 5.8 parts per billion, the current safety limit for mercury. About one out of every six women of childbearing age has enough mercury in her blood to fit into that category and pose a threat to her fetus, according to statistics presented by EPA researcher Dr. Kathryn Mahaffey, the author of the report.
Dr. Kathryn Mahaffey looked at mercury blood levels among 1,709 women of childbearing age during the period from 1999 through 2000. About 7.8% of the women had unsafe mercury levels of at least 5.8 parts per billion. These high mercury levels were associated with fish consumption. Dr. Mahaffey's report was presented at the National Forum on Contaminants in Fish, an annual convention of EPA officials and other public health and environmental professionals.
Mercury Exposure Through Diet
Fish species that contain high concentrations of mercury include tilefish, shark, king mackerel, tuna, and swordfish. The Food and Drug Administration has issued warnings to pregnant women about the dangers of eating large predatory fish. The EPA has also recently advised the public about the high levels of another contaminant, polychlorinated biphenyl or PCB, in farmed salmon.
Coal-fired electric power plants are a major source of mercury pollution. Other large sources are emissions from industrial boilers and burning hazardous waste, according to the EPA (Mercury, Frequent Questions). Mercury can become airborne, then fall to the ground, where it gets into the soil and groundwater. Microorganisms convert part of the mercury to methylmercury, an organic substance that can be very toxic. Small organisms take up the methylmercury, then get eaten by larger animals, and so on up the food chain. At each stage, the amount of methylmercury becomes more concentrated. Among the fish population, the largest fish have the highest amount of methylmercury.
Mercury also occurs in a metallic form as a shiny liquid and can form mercury salts when combined with chlorine, sulfur, or oxygen. Mercury metal is used in chlorine production, as well as in thermometers, dental fillings, and batteries. Mercury salts are sometimes used in skin creams.
Mercury exposure can permanently damage the brain, kidneys, and developing fetus. It may result in changes in vision, hearing, and memory. Children are especially sensitive to mercury. Women exposed to high levels of methylmercury during pregnancy have greater risks of having children with developmental problems, including mental retardation, lack of coordination, and delays in learning to walk and talk (Mercury, Agency for Toxic Substances and Disease Registry).
For more information about mercury, see the EPA Mercury home page. Dr. Mahaffey's study about mercury in newborns is available on the EPA web site. (You will need Adobe Acrobat software to access the file. If you do not have this software or need to upgrade to a current version, you may download a free copy at the Adobe web site.)
At Brayton Purcell, we are concerned about exposure to harmful substances such as mercury. If you have developed an injury through exposure to a toxic substance, please feel free to contact us to learn about your legal options. We have been handling cases concerning unsafe products and toxic substances for over 20 years.