I hate to be the bearer of bad news, but 10 is not the level at which you should start to worry, less than 10 is.

http://www.slate.com/id/2172544/

"Though federal authorities refuse to admit it, it's increasingly clear that no safe threshold for lead exists, and even the tiniest amount can hurt children's developing brains."

"In 2003, Bruce Lanphear and colleagues wrote in the New England Journal of Medicine that kids with lead levels less than 10 mcg/dl lost roughly 7 IQ points."

The same piece also lays out the background and circumstances by which you weren't alerted to the high 'but safe' results detected when your child was 2, and why American parents aren't being warned about levels of lead poisoning that the science indicates is dangerous to their children's health (sound familiar?).

"hough lead paint in homes was banned in 1978, pro-lead lobbyists persuaded then-Vice President George Bush in 1982 to recommend removing limitations on leaded gasoline (the effort ultimately failed). In the 1980s, the Reagan administration barred the CDC from collecting data on national pediatric lead levels."

"just before the CDC considered lowering lead limits once again in 2003, Secretary of Health and Human Services Tommy Thompson removed a qualified scientist, Michael Weitzman, from the CDC's lead advisory committee and then rejected the appointments of Bruce Lanphear and Susan Klitzman, the researchers who found toxic effects of lead at low levels. Instead, Thompson moved to appoint Joyce Tsuji, who worked for two companies that represented lead firms, and William Banner, who has stated publicly that 70 mcg/dl of lead is safe for children's brains—a view not shared by any respectable scientists."

There is no floor on how low these guys will go.