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Shining a light on lead

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POSTED: October 17, 2007 5:05 a.m.

Recent revelations of lead-contaminated paint on toys imported from China have reinforced the dangers of lead to children’s health. They have not, however, highlighted the enormous success and progress made over the past 40 years in reducing that danger.  

Since the time of the Romans - and probably before - lead’s desirable properties led to its use in many products and in large quantities. Until the 1960s, lead was pervasive in America’s environment and its people. While about 83 percent of private homes and 86 percent of public housing units built before 1980 contained lead-based paint, lead wasn’t merely on the walls:

It was used to seal water pipes and containers. In 1981, nearly half the nation’s food and soft-drink cans were sealed with lead solder. Lead dissolved into the water in the pipes and into food and drink in those containers, and it was ingested. 

Today, lead is no longer used to seal water pipes and cans, and lead-based paint has been eliminated.

Paint in old houses is said to be the main hazard for lead contamination of children. According to the Environmental Protection Agency, lead paint poisoning continues to be a concern for as many as 310,000 children under age 6. 

In the middle of the 20th century, lead was used as a gasoline additive, resulting in a massive lead contamination of the environment. In the mid-’70s, more than 200,000 tons of lead were released annually into the air from fuels burned in the United States. By 2006,  the measurements reflect the improvement: Atlanta’s air averaged 1.69 micrograms per cubic meter in the highest quarter of the years 1970-79; by the 1990s, it had decreased by 98 percent. The EPA reports that "From 1980 to 2005, the national annual maximum quarterly average has gone down 96 percent," and just two areas in the nation - in East Helena, Mont., and Herculaneum, Mo. - have been designated out of attainment of federal air quality standards. 

Health dangers resulted in a ban on most uses of lead. Has the banning improved our health? Studies conducted over the past two decades (largely unpublicized) show the answer is a resounding yes.

Today, the main lead threat cited is reduced mental abilities of exposed children. Based on several studies, a decrease of 10 micrograms of lead per deciliter of blood results in about 2.5 points increase in IQ. So, on average an American born today would be smarter than one born in the 1970s by 3.4 IQ points because lead has been removed from our food, water and surroundings.  

IQ is useful in many ways, not the least of which is giving parents and grandparents scientific evidence to prove their children and grandchildren are smarter. Higher IQ is supposed to translate into greater earning power. Experience, however, tells us it is not quite that simple. In this regard, two studies in 2002 show that this small part of overall environmental improvement has provided great monetary benefits.  

The first study emphasizes the threat of not getting the rest of the lead out. The authors calculated that the amount of lead in the blood of American 5-year-olds in 1998 (an average of 2.7 micrograms per deciliter) costs the country $43.4 billion per year in decreased brain power just for that group of children over their lifetime. 

The second study tells the good news of progress already made. In that study, it was calculated that American children born in 1998 will reap $213 billion, as a group. This is because they will grow up nearly lead-free. Instead of having 15 micrograms per deciliter of blood as the average child of the 1970s or earlier did, the level will be less than two. Eighty-two percent of children ages 1-5 were above the current 10 microgram per deciliter "level of concern" in 1976-1980; in 1999-2000 it was 2.2 percent (see table). 

Lead in Georgia children is below the national average and is still dropping. Georgia has sampled children up to age 5 for lead (Georgia Lead Poisoning Prevention Program) since 1998. Of the nearly 50,000 children sampled in 1998 and 1999, only 1.5 percent had blood lead levels above the "level of concern;" in 2006, it was only 0.3 percent. Georgia identified 12 counties as high risk, but the percentage above 10 micrograms per deciliter was the same in those counties as the average for the state. Even this low percentage of children reported above the "level of concern" is probably inflated. Children are selected for screening based on "high risk" criteria including "Medicaid- or PeachCare for Kids-eligible," "WIC eligible" children, and those adopted from outside the country. 

Lead in the blood of Americans keeps decreasing, but it can’t go much lower. We are fast reaching the time when warnings about lead poisoning will raise awareness about as much as expiration dates on bottled water. 

University of Georgia Professor Emeritus R. Harold Brown is an Adjunct Scholar with the Georgia Public Policy Foundation and author of "The Greening of Georgia: The Improvement of the Environment in the Twentieth Century." The Georgia Public Policy Foundation is an independent think tank that proposes practical, market-oriented approaches to public policy to improve the lives of Georgians.

 

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