What blood lead level constitutes lead poisoning in children? A draft report issued by an advisory committee of the Centers for Disease Control and Prevention in January 2012 says the threshold of concern should be lower to protect children. The report, based on the latest science showing that adverse health effects in children can take place at a blood lead level (BLL) of 5 micrograms per deciliter of blood, argues that the current level of concern—10 micrograms per deciliter—is too high. This makes it more crucial to protect children from exposure to lead in the first place, according to the report.
If adopted, the number of 1- to 5-year-olds identified as having elevated BLLs would reach approximately 450,000 in the U.S., according to the report. This should trigger interventions that include environmental investigations, lead-related education, and additional medical monitoring. Consumer Reports has long believed that the CDC should lower its definition of lead poisoning to 5 mcg/dL. [Update: In May 2012, the CDC lowered the limit for child lead poisoning from 10 mcg per deciliter to five.]
Created at the request of the National Institute for Occupational Safety and Health (NIOSH), part of the CDC, the National Toxicology Program’s report was “an overview of the science to date, an evaluation of the evidence of health effects of lead in humans,” says Andrew Rooney, Ph.D., senior health scientist at the U.S. National Toxicology Program, who led the development of the document. “Lead exposure is a significant human health concern,” Rooney says, adding that the report builds upon what other agencies—including the Environmental Protection Agency (EPA), the Agency for Toxic Substances and Disease Registry (ATSDR), and the CDC—have said for years. The conclusion: “Elimination of all lead exposure from the environment is our best course of action,” Rooney says.
Lead can be toxic to people of any age, but young children are at greatest risk because their bodies absorb more of it, and they are more vulnerable than adults to the effects of lead exposure. Hundreds of thousands of children in the U.S. have elevated levels in their blood, according to the National Center for Health Statistics. Even at the lower threshold of 5 mcg/dL, lead in the blood can have adverse health effects on a child’s cognitive function, academic performance, and endocrine systems—effects that may be irreversible. Too much lead in a child’s blood may lead to anemia, decreased muscle and bone growth, hearing damage, learning disabilities, nervous system and kidney damage, speech, language, and behavior problems, and brain damage. At extremely high levels (about 70 mcg/dL), it can cause severe neurological effects in children, and lead to lethargy, convulsions, coma, and even death. But even at extremely low levels, the World Health Organization reports, effects have been observed on the metabolism, kidneys, and cardiovascular symptoms.
The good news is that since the 1970s, the average blood lead levels in children younger than 6 has dropped by about 90 percent because of a federal ban on lead in house paint and gasoline. Still, in the U.S., lead-based paint hazards, including deteriorated paint and lead-contaminated dust and soil, remain the largest contributors to childhood lead exposure. And children between the ages of 1 and 5 have consistently higher BLLs than any other age group because they handle lead-contaminated dust, soil, paint, toys, and more.
A fetus can be exposed to lead in the womb, since it can cross the placenta, and as a result, infants are usually born with a lead blood level similar to that of the mother. This lead transfer can contribute to adverse effects in the fetus, including reduced growth and kidney damage. Currently, the CDC recommends follow-up blood lead testing and interventions for pregnant women whose blood lead levels are equal to or greater than 5 mcg/dL.
Since no amount of lead in the blood is safe, the report recommends that public health, environmental, and housing policies increase awareness of the hazards, prevent the exposure to children (vs. after-the fact intervention), and help children with high lead levels with nutritional intervention.
Consumer Reports has been continuously concerned about lead exposure among children starting with a report on lead in children’s toys (PDF) in the magazine's first issue, in May 1936. The article stated, “Numerous small, one-piece metal toys such as soldiers, automobiles, airplanes, etc., were found to be made of a soft metal alloy containing a high percentage of lead.” Lead, we reported then, “is a poison which accumulates in the body, and can do great damage in amounts almost infinitesimally small” and that “some medical authorities believe that lead presents one of the gravest hazards of childhood.” As recently as January 2012, we reported on arsenic and lead in juice. “The science has been indicating for some time that there may be no safe limit of lead for children, who are more vulnerable to its toxicity,” says Urvashi Rangan, director of Consumer Safety and Sustainability for Consumer Reports. “A lower lead tolerance for children makes total sense.”