In 2002 researchers at South Africa's Medical Research Council collected blood from first-graders in impoverished townships of Johannesburg to check their exposure to lead, a powerful neurotoxicant. The children's blood lead levels were high by today's standards, averaging 9 μg/dL. But one student had 52 μg/dL of lead coursing through her veins, far above the 5-μg/dL concentration at which intervention is currently recommended in the United States. The researchers went to her apartment to investigate and met a skinny, withdrawn little girl and her parents.
"You're here because of what she eats," study leader Angela Mathee recalls the girl's mother saying. Huge patches of pale lemon-yellow paint were missing from every wall in the apartment, where the girl had spent hours chipping it away and eating it. The windowpanes were loose because she had eaten the painted putty holding them in place, and the dirt outside was pitted where she had devoured it, too. Carmelita (a pseudonym) had severe pica, the compulsive consumption of nonfood substances. Her parents had taken her to various doctors, but they had offered little help. None had tested her blood, although lead poisoning often shadows pica like a phantom.
When Mathee met Carmelita, it had been decades since developed nations had banned lead-based paint, and South African paint companies had long before voluntarily agreed to abandon lead, too. But when Mathee tested paint from the apartment walls it was loaded with lead, even though Carmelita's parents said they'd purchased it recently.
While pica presents a dramatic example of exposure to lead, far more children can be dangerously exposed just by inadvertently consuming dust from deteriorating paint through normal activity. Often, lead exposure has no observable symptoms and goes unrecognized. But early exposure can cause profound neurobehavioral problems including decreased life-long intellectual performance and behavioral changes—even at blood concentrations below 5 μg/dL, which researchers once thought far too low to harm kids. Lead exposure has also been associated with Alzheimer's disease and cardiovascular disease.
Disturbed by what they found in Carmelita's apartment, Mathee's team surveyed homes across Johannesburg. They discovered that 20% of the homes sampled, both old and new, rich and poor, had lead-based paint on the walls. Most of the colored oil-based household paints for sale in stores contained lead, too, often at concentrations thousands of times above the current U.S. standard of 90 ppm. When the investigators tested paints on children's toys, they again found lead. Mathee was horrified to discover levels as high as 135,000 ppm on toys in her own home—including building blocks bearing her young daughter's tooth marks.
"At that time I had been working on lead issues for nearly two decades, and it struck home that unless there are protective measures in place … none of us, no matter how much you know, can protect your children against this public health hazard," Mathee says. "We have to put in place broad measures, regulatory measures, to protect everyone."
The team's evidence convinced the government to ban lead in household paints, effective in 2010. Mathee's team helped Carmelita get treatment and had her apartment remediated, but the girl continued to struggle with pica, and eventually they lost track of her. She would be about 19 now, Mathee guesses. "Had it not been for Carmelita, we probably wouldn't have paint lead regulations in place in the country now," Mathee says. "The South African public owes her a debt of gratitude."
Even so, South Africa still has a long way to go. Subsequent testing by Mathee's team shows that lead-based paints are still widely sold, despite calls by researchers and South Africa's main paint manufacturers association for the government to start prosecuting companies that violate the law. In addition, Mathee says, many doctors remain unaware of the extent of lead exposure in children, and the country lacks fundamental infrastructure and systems to diagnose and treat lead poisoning. There are no childhood blood lead standards or any national surveillance programs in place in South Africa to reveal how many children are exposed countrywide. Public awareness of lead hazards is low, she says, and most people don't know that lead-based paint could be in their homes, let alone how to safely maintain or renovate painted surfaces.
For all that, South Africa is a step ahead of most developing nations. Rising incomes have enabled more and more people to afford a splash of color in their lives, with booming sales in decorative paints used on homes, furniture, toys, and more. Yet few of these countries regulate lead in paint at all. And paints loaded with lead are readily available on store shelves, rarely bearing any labeling to warn consumers of the dangers they pose, a spate of recent studies shows. Now, however, an international effort is gathering steam to remove lead from paints once and for all.