EVANSTON, Ill. - Armed with sunflowers, corn, kale, grass and science, a Northwestern University environmental engineer and a Children's Memorial Hospital pediatrician hope to determine the best way to reduce a major health problem facing children in Chicago: lead poisoning from contaminated soil.

Helen J. Binns, M.D., a researcher at Children's Memorial Institute for Education and Research, and Kimberly A. Gray, associate professor of civil engineering at Northwestern, are leading a federally funded, two-year phytoremediation project in Chicago's West Town community. Their mission is to fight lead poisoning with plants. The study will provide data necessary to develop a more widespread intervention program for urban centers across the country that need inexpensive methods to combat lead-contaminated soil.

Archi-treasures, a not-for-profit organization that works in Chicago neighborhoods to raise community involvement in the urban landscape, has planted different kinds of grasses and vegetation in the yards and gardens of 40 West Town homes. The selection of plantings is based on the research and results of scientific experiments that Gray is conducting in her laboratory. Twenty other homes will act as a control group and receive no plantings this year.

"Phytoremediation is the use of living green plants to remove toxins from the soil or other contaminated areas," said Gray. "My students and I came up with a list of plants - goldenrod, sunflowers, corn and others - that should extract lead from the West Town soil. We just don't know to what degree. At the end of the season, we'll test the plants and soils for their lead content. Our goal is to learn which plants remove lead from these soils and what the best conditions are for the lead removal."

Gray stressed that although phytoremediation can seem as simple as routine gardening and landscaping, it is more complex. Phytoremediation requires testing local soil conditions before planting, selecting appropriate green plants and regular monitoring.

While the risk from interior leaded paint and paint chips from building exteriors is likely higher, lead-contaminated soil is a significant source of lead poisoning. In the case of West Town, many of the yards of the brick and frame homes have large areas of bare soil, potentially increasing children's exposure to lead. More than 20 percent of West Town children 6 years old and younger have elevated blood lead levels, according to the Chicago Department of Public Health. Many other Chicago community areas are similar; over one-third of Chicago's community areas have even higher rates of childhood lead poisoning.

"Chicago has one of the highest rates of lead poisoning in the country," said Binns, also assistant professor of pediatrics at Northwestern's Medical School. "This is an enormous health concern. Lead poisoning in young children can cause permanent damage to the central nervous system and reduced intellectual capability. Children who appear healthy can have dangerous levels of lead in their blood."

The Binns-Gray research team has received a two-year, $900,000 grant from the U.S. Department of Housing and Urban Development (HUD) to evaluate lower-cost approaches to soil lead contamination in urban areas, with an emphasis on phytoremediation. Binns is the lead investigator of the study, called the Safer Yards Project.

The Safer Yards Project builds on a lead abatement project conducted in West Town from 1995 to 1998, for which Binns conducted the evaluation. During the first project, the threat of lead poisoning from interior sources, such as paint dust, was reduced, but researchers discovered that soil lead levels were unusually high in a four-block-square area. That area is one of the two focus areas for the Safer Yards Project.

"This type of phytoremediation study has never been done before," said Binns. "We're taking a hard look at the soil. What plants make a difference in soil contamination? What types of barriers, such as grass, mulch or stone, provide successful long-term covering of contaminated soil? We need to develop an inexpensive solution to this common urban problem."

Twenty of the 40 homes receiving plantings this year have raised bed gardens, and the other 20 have regular gardens. All of these gardens contain a variety of lead-extracting plants. The rest of the yard space of all 40 homes feature both physical barriers (mulch and stone) and plant barriers (a blend of grasses), preventing children from coming into contact with the lead particles in the soil. Archi-treasures has hired a crew of local residents to maintain the properties. The Safer Yards Project's community health partner, Erie Family Health Center, is coordinating activities in the community.

"Ideally there will be no bare soil in any of the yards, except for those in the control group," said Mary E. Finster, a graduate student working with Gray. "We are hoping to find that grass also removes lead from the soil. However, if it does, we expect that it will do so at a much slower rate than the other plants."

Throughout the study, the researchers are testing for lead in the dust from foot traffic in common areas, such as porches. At the end of the growing season, Gray and her students will remove the plants and test different parts of each plant for lead levels. Grass also will be tested for lead content. Soil from different sections of each of the 60 yards will be tested, and the data will be compared with data taken prior to the plantings.

Gray is interested in discovering the optimum conditions for grass and plant growth in these polluted soils. For example, what is the best blend of grass seeds? Should the soil pH be altered? How should the fertilizer be applied? She and Finster also will determine if the plants stabilize the lead in the soil, making it less bioavailable, or if the plants accumulate the lead in their roots or shoots. In addition, they will analyze how the form of the lead changes as a result of plant growth.

All of the plantings and testings will be repeated next year. The difference in year two is that the 20 homes in the control group also will receive plantings. During both years, Gray and her students will continue to grow and test plants in the laboratory, searching for the most efficient lead-extracting plants.

"The bottom line is that we want to limit children's exposure to lead," said Gray.

The researchers also are studying how children play in urban environments. By taking a survey of West Town families, they will answer questions such as where children play and how much time they spend outside. Young children are being videotaped while playing in their yards and neighborhoods to determine favorite sites of play and the amount of contact children have with soil while playing outdoors.

"It is likely that there are many sources for the lead that contaminates soil in urban areas," said Binns. "Our past soil lead mapping of a residential area showed a pattern of peaks and valleys of lead levels. I suspect that much of the contamination has come from deteriorated paint, past use of lead-containing gasoline and industrial air pollution, which has settled widely in the city. Lead in soil does not disintegrate or decay. Contamination which occurred 50 or more years ago is still present today."

"The important thing to note," added Binns, "is that the West Town neighborhood is similar to many other Chicago neighborhoods. Soil lead contamination in urban areas is a major problem that needs to be addressed."

Other participants in the project include James Olson, M.D., Erie Family Health Center; Joyce Fernandes, archi-treasures; and Nicholas Peneff, Public Health and Safety, Inc.