Post by Christine on Aug 11, 2008 5:04:59 GMT -5
Lead may lurk in backyard gardens
Contamination of soil common
By Beth Daley, Globe Staff | August 11, 2008
As backyard vegetable gardens undergo a renaissance, environmental officials and scientists are warning homeowners to be careful before planting the carrots and chard: There might be lead in the soil.
Flakes of lead paint from old homes often create a halo of contamination around houses that vegetables can take up. Remnants of leaded gasoline might also be in the soil, especially near busy roads. While the problem is pervasive in urban areas, suburban homes that were built on or near apple orchards are also at risk because lead arsenate was once used regularly as a pesticide. The heavy metal can remain in soil for hundreds of years.
"If I had a garden in the urban environment I would just assume there is lead in the soil," said Wendy Heiger-Bernays, associate professor of environmental health at the Boston University School of Public Health. She said lead shouldn't stop people from planting vegetables, but gardeners need to take specific steps to prevent the plants from taking it up.
Although soil around homes can contain everything from arsenic to motor oil, lead is one of the most common, and to children, one of the most dangerous: Even tiny amounts measured in blood levels can cause learning disabilities and behavioral prob lems. Most children who are lead poisoned are exposed from a variety of sources, with lead paint the most prominent, Heiger-Bernays said. But environmental and health authorities say vegetables grown in lead-contaminated soil also contribute to the problem.
In adults, lead can cause or contribute to high blood pressure, reproductive problems, and memory loss.
The US Environmental Protection Agency considers garden soil contaminated if it has 400 parts lead per million parts of soil.
The University of Massachusetts at Amherst's Soil and Plant Tissue Testing Lab, which charges $9 a sample, normally receives about 10,000 soil sample requests a year for soil to be tested for a suite of contaminants, including lead. This year, the lab is on track to get about 16,000. Lab director Steve Bodine said he does not know exactly why people are sending in more soil samples, but believes it is at least in part because of an increased interest in vegetable gardening. Typically, about 10 percent of the homes tested show unsafe levels of lead.
The Food Project, a local nonprofit that helps people create lead-safe backyard gardens, has tested more than 125 home plots in Dorchester and Roxbury in recent years, and found 83 percent of them contaminated with lead - 1,000 parts per million on average. The nonprofit now builds raised beds with clean soil for backyard gardeners.
Bessie Hood took advantage of their offer this year to get a raised bed for her collard greens, beets, and green beans.
Hood, who grew up on a cotton farm in South Carolina, was surprised when she learned at a community meeting that soil in much of her Dorchester neighborhood was contaminated with lead.
"To be honest, I didn't even think that lead would affect [the vegetables]," said Hood. Now, "I wish the raised bed was bigger."
About 22 percent of all households in the United States had some sort of vegetable backyard garden in 2007, according to Bruce Butterfield, research director for the National Gardening Association. Backyard gardening tends to spike during tough economic times. During the energy crisis in the 1970s when President Gerald Ford urged people to plant Whip Inflation Now, or WIN gardens, 49 percent of households grew vegetable gardens.
"Gas prices, food prices are high and people realize that [growing your own] is better tasting, better quality food," Butterfield said.
Lead contamination can vary greatly among communities - and house plots. The most contaminated part of a backyard is within about 6 feet from the building, where paint may have flaked or been scraped off. But other areas are often contaminated as well.
Having lead doesn't have to mean no garden, however. Environmental and health officials say if you live in an urban area, first pick a place for a garden away from the house. If that soil tests high for lead, build a raised bed and place clean soil in it. People do need to monitor raised beds because they can become contaminated by windblown lead dust, said Dan Brabander, a geochemist at Wellesley College.
Gardeners should also plant fruiting crops such as tomatoes, squash, peas, and corn because they take up relatively little lead. At the same time, people should avoid planting root vegetables, potatoes, and leafy vegetables, which take up more. Gardeners should also use mulch, which keeps the lead-contaminated soil contained.
"People need to be careful, be prudent," said Carol Rowan-West, director of the state Department of Environmental Protection's Office & Research and Standards. "They need to have their soil tested."
Some scientists and homeowners try other methods. Brabander and The Food Project experimented several years ago with planting mustard greens and other plants that take up large amounts of lead to see if they could rid soil of lead. While it could theoretically work, cleaning a small garden plot could take decades, Brabander said.
Sam Fogel, a Newton microbiologist and avid gardener, said phosphate spread over soil can bind with lead and make it unavailable for plants to take up. The phosphate must be thoroughly mixed into the 6- to 8-inch soil depth. Gardeners can retest their soil after spreading phosphate to see if it is truly binding.
Yet Brabander said such effort in a backyard garden may not be easy or practical for the average homeowner.
"We don't want to discourage people from gardening," said Heiger-Bernays.
"We want people to garden safely and have a harvest to reap the benefits of nutrition, social and health from working in the garden."
Beth Daley can be reached at bdaley@globe.com.
Contamination of soil common
By Beth Daley, Globe Staff | August 11, 2008
As backyard vegetable gardens undergo a renaissance, environmental officials and scientists are warning homeowners to be careful before planting the carrots and chard: There might be lead in the soil.
Flakes of lead paint from old homes often create a halo of contamination around houses that vegetables can take up. Remnants of leaded gasoline might also be in the soil, especially near busy roads. While the problem is pervasive in urban areas, suburban homes that were built on or near apple orchards are also at risk because lead arsenate was once used regularly as a pesticide. The heavy metal can remain in soil for hundreds of years.
"If I had a garden in the urban environment I would just assume there is lead in the soil," said Wendy Heiger-Bernays, associate professor of environmental health at the Boston University School of Public Health. She said lead shouldn't stop people from planting vegetables, but gardeners need to take specific steps to prevent the plants from taking it up.
Although soil around homes can contain everything from arsenic to motor oil, lead is one of the most common, and to children, one of the most dangerous: Even tiny amounts measured in blood levels can cause learning disabilities and behavioral prob lems. Most children who are lead poisoned are exposed from a variety of sources, with lead paint the most prominent, Heiger-Bernays said. But environmental and health authorities say vegetables grown in lead-contaminated soil also contribute to the problem.
In adults, lead can cause or contribute to high blood pressure, reproductive problems, and memory loss.
The US Environmental Protection Agency considers garden soil contaminated if it has 400 parts lead per million parts of soil.
The University of Massachusetts at Amherst's Soil and Plant Tissue Testing Lab, which charges $9 a sample, normally receives about 10,000 soil sample requests a year for soil to be tested for a suite of contaminants, including lead. This year, the lab is on track to get about 16,000. Lab director Steve Bodine said he does not know exactly why people are sending in more soil samples, but believes it is at least in part because of an increased interest in vegetable gardening. Typically, about 10 percent of the homes tested show unsafe levels of lead.
The Food Project, a local nonprofit that helps people create lead-safe backyard gardens, has tested more than 125 home plots in Dorchester and Roxbury in recent years, and found 83 percent of them contaminated with lead - 1,000 parts per million on average. The nonprofit now builds raised beds with clean soil for backyard gardeners.
Bessie Hood took advantage of their offer this year to get a raised bed for her collard greens, beets, and green beans.
Hood, who grew up on a cotton farm in South Carolina, was surprised when she learned at a community meeting that soil in much of her Dorchester neighborhood was contaminated with lead.
"To be honest, I didn't even think that lead would affect [the vegetables]," said Hood. Now, "I wish the raised bed was bigger."
About 22 percent of all households in the United States had some sort of vegetable backyard garden in 2007, according to Bruce Butterfield, research director for the National Gardening Association. Backyard gardening tends to spike during tough economic times. During the energy crisis in the 1970s when President Gerald Ford urged people to plant Whip Inflation Now, or WIN gardens, 49 percent of households grew vegetable gardens.
"Gas prices, food prices are high and people realize that [growing your own] is better tasting, better quality food," Butterfield said.
Lead contamination can vary greatly among communities - and house plots. The most contaminated part of a backyard is within about 6 feet from the building, where paint may have flaked or been scraped off. But other areas are often contaminated as well.
Having lead doesn't have to mean no garden, however. Environmental and health officials say if you live in an urban area, first pick a place for a garden away from the house. If that soil tests high for lead, build a raised bed and place clean soil in it. People do need to monitor raised beds because they can become contaminated by windblown lead dust, said Dan Brabander, a geochemist at Wellesley College.
Gardeners should also plant fruiting crops such as tomatoes, squash, peas, and corn because they take up relatively little lead. At the same time, people should avoid planting root vegetables, potatoes, and leafy vegetables, which take up more. Gardeners should also use mulch, which keeps the lead-contaminated soil contained.
"People need to be careful, be prudent," said Carol Rowan-West, director of the state Department of Environmental Protection's Office & Research and Standards. "They need to have their soil tested."
Some scientists and homeowners try other methods. Brabander and The Food Project experimented several years ago with planting mustard greens and other plants that take up large amounts of lead to see if they could rid soil of lead. While it could theoretically work, cleaning a small garden plot could take decades, Brabander said.
Sam Fogel, a Newton microbiologist and avid gardener, said phosphate spread over soil can bind with lead and make it unavailable for plants to take up. The phosphate must be thoroughly mixed into the 6- to 8-inch soil depth. Gardeners can retest their soil after spreading phosphate to see if it is truly binding.
Yet Brabander said such effort in a backyard garden may not be easy or practical for the average homeowner.
"We don't want to discourage people from gardening," said Heiger-Bernays.
"We want people to garden safely and have a harvest to reap the benefits of nutrition, social and health from working in the garden."
Beth Daley can be reached at bdaley@globe.com.