The Environmental Protection Agency and Department of Housing and Urban Development advise (but do not require) remediation if lead levels in soil exceed 400 parts per million in children’s play areas and 1,200 p.p.m. elsewhere. But some states and cities have set much lower limits. For example, 100 p.p.m. is considered hazardous in Minneapolis. In the Netherlands, 40 p.p.m. is unacceptable. Unpolluted soil averages 10 p.p.m. Mr. Meuschke’s soil had lead levels of 939 p.p.m.

Since 2003, hazardous amounts of lead have been documented in backyard and community gardens in New York as well as in Baltimore, Boston, Chicago, Detroit, Indianapolis, Los Angeles, Minneapolis, New Orleans, Philadelphia and Washington. Lead-laden soil has been found not only in inner city neighborhoods but also suburban areas.

“It doesn’t matter if you’re rich or poor,” said David Johnson, a professor of environmental chemistry at the State University of New York College of Environmental Science and Forestry in Syracuse, where he has found lead concentrations as high as 65,000 p.p.m. in the yards of upscale homes. “Lead knows no socioeconomic boundaries.”

Excessive lead in soil is the legacy not only of lead paint but also of leaded gasoline, lead plumbing and lead arsenate pesticides. Although these products were outlawed decades ago, their remnants linger in the environment. Lead batteries and automotive parts, particularly wheel balancing weights, are still widely used and are sources of soil contamination.

Soil is likely to contain high levels of lead if it is near any structure built before 1978, when lead-based paint was taken off the market, or if a building of that vintage was ever demolished on the site. Pesticides containing lead were often used on fruit trees, so land close to old orchards is also of concern. And beware of soil around heavily trafficked roadways; it, too, is probably laced with lead. But environmental engineers and soil experts said any place is potentially tainted.

“It’s kind of a dirty secret nobody really knows about because we’re all distracted worrying about lead in toys from China,” said Gabriel Filippelli, a professor of earth science at Indiana University-Purdue University in Indianapolis who has published several papers on lead accumulation in soil. His and other research indicates lead levels in people’s blood correspond directly to the amount of lead in the soil where they live.