How Much Lead Is Too Much?
The government has done an excellent job of reducing lead exposure by banning the use of lead-based paint and lead plumbing supplies and through the phasing out of lead in gasoline. The decrease in the incidence of lead poisoning has been dramatic -- 88 percent of children under the age of 6 were found to have had elevated blood levels between 1976 and 1980, compared to just 2 percent (an admittedly soft number) in the survey period running from 1999 to 2000.
But most of these stats measure results under guidelines issued by the Centers for Disease Control and Prevention (CDC) in 1991, which classify toxicity as BLLs of 10 micrograms per deciliter or greater. These guidelines are now under strong attack. Studies by researchers such as Bruce Lanphear, MD, MPH, director of the Cincinnati Children's Environmental Health Center at the Cincinnati Children's Hospital Medical Center and considered by many to be the country's top pediatric lead researcher, have demonstrated that much smaller amounts of lead than those permissible under the current CDC rules could put children at risk for all the cognitive damage excessive lead can wreak.
Is Even 10 Micrograms of Lead Too Much?
In one 5-year study, in which researchers from Cornell University and the University of Rochester School of Medicine participated, children with BLLs below the 10 micrograms per deciliter threshold showed "intellectual impairment" from the lead exposure, with the amount of impairment most pronounced at the lower levels.
What type of impairment? Maybe 5 IQ points at the lower levels, which is not nothing. We wouldn't be at all surprised if new guidelines are eventually issued that will reduce the previous standard for acceptable blood levels in children by as much as 50 percent. But eventually is the operative word here. As Dr. Lanphear warns, "The laws catching up to the science could take a week, a month, or five years..."
Should you care? Well, in the 1970s, when the bulk of today's parents were toddling around, the average BLL for all American kids was 25 micrograms (and look how great we all turned out). But after reading reams of material and talking with many top docs who are so concerned about lead, we believe keeping your kids at very conservative BLLs (below the proposed replacement standard of 5 BLLs) is both warranted and attainable without enormous amounts of effort on your part. Besides, we do all want our children to turn out even better than we did, don't we?