Mary Sue Schottenfels, executive director of CLEARCorps, a nonprofit group that kick-started the cleanup of the Thomas home, said her organization and others lobbied for new city laws that now hold landlords accountable for keeping properties lead-free. Under a 2010 law, landlords must check homes built before 1978, and if lead is found, they cannot rent them until they are cleaned up to state standards.
Thompson said population declines and demolishing of older homes also have led to fewer lead-poisoned kids in Detroit. The city’s population has plunged 25 percent since 2000, and its rental vacancy rate is about 19 percent. In addition, under Mayor Dave Bing, the city has demolished 6,700 vacant homes and buildings in the past three years.
“Basically in a shrinking city, less children are getting exposed,” Thompson said.
No safe levels
Last October, the CDC cut its guideline for lead in half, to 5 micrograms per deciliter of blood, in response to mounting scientific evidence that low levels can harm children’s developing brains.
Under the new health guideline, 10.2 percent of Detroit children age 6 and younger had excessive lead levels in 2011, compared with 33.3 percent in 2004 that exceeded that level, according to data from the Michigan Department of Community Health. For Cleveland, it’s 17.6 percent of children, and for Milwaukee, 12.9 percent.
All those percentages remain much higher than the national average – 5.8 percent in 2011.
Nevertheless, Detroit now has 70 percent fewer kids with lead levels considered unhealthful. Based on the previous CDC guideline, the improvement was even greater – more than a 90-percent decline between 2004 and 2011.
Researchers and medical professionals applauded the lowering of the federal threshold. But they say it may not be low enough.
“Scientifically, there is no safe level of lead exposure,” said Dr. Bruce Lanphear, a professor at Simon Fraser University in Vancouver, Canada, who specializes in childhood exposures to lead and other toxics that affect the brain.
It appears that impacts of lead occur even at blood levels below 2 micrograms per deciliter, Lanphear said.
Also, exposure to low levels leads to a quicker loss in IQ points, he said. When children’s blood lead levels increased from 2.4 to 10 micrograms per deciliter, IQs dropped by 3.9 points, compared with a 1.1 point drop when levels increased from 20 to 30 micrograms per deciliter, according to a 2005 Lanphear study.
Lead has been linked to poor school performance among Detroit children. City researchers found that children with higher lead levels were more likely to need special education, and, as blood lead levels went up, students’ math, reading and writing scores dropped, according to a 2010 study. Children with blood lead levels as low as 5 micrograms per deciliter also are more likely to be arrested, according to a 2008 study by the University of Cincinnati.
Poorer children consistently have higher levels of lead. But, even controlling for income and other factors, black children still have blood levels 50 percent higher than other races, Lanphear said. Research suggests black children metabolize the metal differently. That magnifies the problem in places such as Detroit, which is 83 percent black.