This is the VOA Special English Agriculture Report.
Soil naturally contains harmless amounts
of lead, along with other metals. Because of pollution, however, the amounts
are higher the closer you get to cities and towns. But experts say this should
not stop gardeners from growing food if they take safety measures.
David Johnson is a
chemistry professor in the State University of New York's College of
Environmental Science and Forestry. He explains that lead can enter the ground
from leaded paint and leaded fuel and from industry.
And once lead gets into the soil, it stays a long time.
It remains an environmental threat especially to children. Lead can harm mental
and physical development even in babies before they are born.
If a test finds that soil has too much lead, you might
be advised to remove the soil or cover it with sod grass. Different countries
have different levels that they consider acceptable.
Rosen of the University of Minnesota Extension notes that concerns about lead have
increased now that more people are planting gardens. But Professor Rosen says
plants generally do not absorb much lead. He says there is likely more risk
from lead dust on plants or from playing in the soil than from the plant itself.
some plants do absorb more than others. Experts say good choices for the garden
include tomatoes, peppers, beans and okra. Among the plants that can absorb
more contaminants, they say, are root crops, leafy vegetables and herbs. If you
grow carrots, for example, you might want to peel them. Dirt may be harder to
remove from some crops than from others. But all produce should be washed.
Gardens should be planted
away from roads and structures, especially old buildings. Home gardeners should
plant away from the foundation of their house. And lead amounts can be especially
high near industrial areas and waste dumps.
should also be tested for its pH level, a measure of the acid and alkaline
balance. Experts say the ability to take up lead is reduced when the pH level
is above six and a half. Adding organic material such as compost to soil can
also make lead less available to plants.
people attempt a process called phytoremediation. They try to remove lead from
soil by growing certain plants that collect it. But Professor Rosen says the
process is complex and may not work.
And that's the VOA Special
English Agriculture Report, written by Jerilyn Watson. For more gardening information,
go to voaspecialenglish.com. I'm Steve Ember.