Toxic At Any LevelApr 21, 2003 | The Times-Picayune A new study on lead and children reaches the frightening conclusion that there is no safe level of exposure to this toxic heavy metal, and that's especially troubling for cities like New Orleans that have a lot of older homes.
Even though lead was removed from gasoline in 1976 and from house paint two years later, it still lingers in soil, water and in homes, especially those built before 1950. In New Orleans, that's about 40 percent of the housing stock.
There's no question that lead is a dangerous substance. Lead exposure during childhood can reduce intelligence, slow development and cause behavioral problems.
What's less clear is how much lead is cause for worry. That's the question the New England Journal of Medicine study sought to answer. Researchers found that even children whose lead levels fell within limits considered safe by the government showed a decrease in IQ test scores.
"People have been asking, 'How low is low enough?' The fact is, in our study we found no evidence for a safe level," said Richard Canfield of Cornell University, one of the study's authors.
As knowledge about lead's toxicity has evolved, the federal government has reduced the level considered to be safe, most recently in 1991. The level now is 10 micrograms per deciliter of blood, which is about 100 parts per billion.
But in this study, researchers found an IQ drop of as much as 7.4 points in children who had less lead in their blood than the level set by the CDC.
Researchers estimated that one in 50 children has a lead level above what is recommended. They estimate that one in 10 children in this country has 5 micrograms of lead per deciliter or more high enough to be of concern, according to the study.
The new research should prompt the CDC to reconsider its 12-year-old guideline. If the current level is too high, as this study indicates, it would be misleading and dangerous to allow it to stand.
The findings could also have implications for lead abatement programs. If lead exposure is dangerous at any level, local, state and federal officials might need to re-evaluate the criteria they use for deciding when it's advisable to remove lead.
The study should also prompt people who live in older structures to assess their own risk. The simple fact that lead-based paint is in a house doesn't mean that its residents are being exposed to the toxin. But when lead-based paint chips, peels or forms dust, people especially children can come into contact with it.
People who are renovating older homes need to be aware of the hazards and do the work in an environmentally sound manner.
Policymakers certainly need to pay attention to this study in deciding how to deal with the 38 million homes in this country that were built before 1950. But parents need to pay attention, too.
Lead is poison for children, and parents need to do everything they can to make sure that their children don't come into contact with it.