Chicken droppings, manure help to clean up DDT
Date: 17-Sep-99
Country: UK
Author: Patricia Reaney
The new technology, which has been tested in Florida, uses bacteria in
the soil that feed on organic waste to break down DDT, one of the so
called "dirty dozen" toxic pollutants, into harmless byproducts.
Dr Neil Gray of Sheridan Park Environmental Laboratory, an Ontario
subsidiary of the Anglo-Swedish drugs group AstraZeneca , told a
British science conference the new bioremediation technology is cheaper
than other methods of dealing with contaminated soil such as
incinerating it or burying it in a landfill.
"This is a new technology. We've just received the first of three (U.S.)
patents on the technology and we've had three more approved just last
week. So it is fairly new off the books," he told a news conference.
"This new process is not only cost-effective, but also has an excellent
overall environmental profile," he added.
The system uses microflora or bacteria that thrive on organic waste such
as cow manure and chicken feed. Although DDT is banned in most western
countries, it is still being used to control malaria in many developing
nations.
"It is a chemical that is fairly persistent in the soil until you
actually treat it," Gray added.
In pilot studies in the laboratory in Canada the researchers were able
to get 97 percent degradation of the DDT in eight weeks. Further tests
on a contaminated site in Tampa, Florida were also promising. But Gray
said the system would have to be customised for each site based on what
is in the soil.
DDT is one of 12 persistent organic pollutants or POPs - dubbed the
"dirty dozen" - that are targeted for restriction or elimination in a
global treaty being negotiated in Geneva under the auspices of the U.N.
Environment Programme.
In talks on Monday negotiators exempted DDT on public health grounds.
The World Health Organisation says it remains the most effective way to
deal with mosquitoes that transmit malaria.
Environmental groups say DDT can travel long distances in the air and
water, that it builds up in the fatty tissues of living beings and that
it builds up in the sub-soil because of its non-biodegradable character.
