A new case study co-authored by COEH members Mark Miller and Gina Solomon, published in Morbidity and Mortality Weekly Report, has linked a skin-lightening cream manufactured in Mexico to mercury contamination cases affecting five households in California and Virginia. In total, fifteen out of twenty-two household members showed evidence of mercury poisoning, including six with no history of using the cream.
Miller, the director of UCSF’s Pediatric Environmental Health Specialty Unit Program (PEHSU), launched the investigation in March 2010 after he was notified that a mother and her three children showed elevated levels of urine mercury while participating in a health study.
“We knew the mercury was inorganic. That told us a lot right off the bat,” said Miller. ”And because there were multiple family members affected, it pointed to something around the household. It was clear the next step was to get the Environmental Protection Agency (EPA) on-site to identify the source.”
Miller began collaborating with the local health department and the California Department of Public Health (CDPH) and in less than 48 hours had an emergency response team from EPA Region 9 conducting real-time air mercury monitoring at the family’s home. “They identified a drawer in the parent’s room and a drawer in the bathroom as contaminated, though the cream wasn’t in the drawers at the time,” said Miller.
CDPH interviewed family members using a questionnaire to identify potential mercury exposures such as thermometers, fluorescent light bulbs, pharmaceuticals, and occupational exposures. They quickly identified the unlabeled skin cream as the source. The bottles were found to contain a mercury content of 2% to 5.7% by weight, an extremely high level, Miller confirmed.
The team discovered two additional households in Virginia were also using the illegally imported cream and brought the Virginia Department of Health (VDH) into the investigation. In all, six of the cream users reported symptoms consistent with mercury poisoning including numbness, tingling, dizziness, forgetfulness, headaches, and depression.
“Mercury has a half-life of two or three months. You rid of it fairly quickly when you’re no longer exposed to it,” said Miller. In July 2010, VDH retested eight household members and found their urinary mercury concentrations, although still elevated, had dropped by 45%.1
Investigators are now urging clinicians to consider skin cream exposure for all cases of mercury poisoning. Their recommendation is based on strong evidence that mercury vapors from stored cream are potentially dangerous to all household members near the product. In addition, children are highly vulnerable through their contact with adult cream users’ skin, contaminated clothing, and non-dietary hand to mouth ingestion.
PEHSU worked with CDPH on a Spanish language education campaign, including radio novellas targeted at Latino listeners. Currently, Miller is collaborating with the Environmental Health Investigations branch of CDPH. By collecting then testing up to 100 samples of imported cream, they will begin to characterize the prevalence of mercury products in communities at risk.
1 Morbidity and Mortality Weekly Report, Mercury Exposure Among Household Users and Nonusers of Skin-Lightening Creams Produced in Mexico — California and Virginia. http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6102a3.htm?s_cid=mm6102a3_x (accessed January 2012).
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