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Local man’s DDT trial cleansing pesticides with mushrooms

Mar 4th, 2013 | By | Category: Editor's Picks, Latest News, News


Grant Lyon has been training mushrooms to fight banned insecticide DDT and says he is the first to succeed in NZ.

In 2009 Mr Lyon, above, began experimenting with oyster mushrooms to cleanse soil of DDT residue.

Mr Lyon volunteers five hours a week at Innermost Gardens, a community garden on Mount Victoria, which was reqularly sprayed with DDT in its former life as a bowling green.

Mr Lyon was originally supported on a minimum wage for ten months by Nancy King of Earthskin Trust but now continues the bioremediation project in his own time.

“Many people attempt this in labs, but the problem is taking the mushrooms out of a sterile environment and putting them in the ground, and getting the process to work as well,” he says.

He plans to rid the garden of all DDT, a toxin which was used during the Second World War to fight malaria and then used as an agricultural insecticide.

It was banned by the United States in 1972 after a journal showed it could lead to cancer and other problems in humans.

DDT was not banned in New Zealand until 1989.

After several experiments growing different mushrooms in bags in the garden shed, the most sterile environment Lyon could find, he tried releasing them into the patch, only for the foreign oyster mushrooms to be beaten by native ones.

“I want to change the structure of the soil, so it is more able to sustain good growth.

“Although I made many mistakes along the way, getting an oyster mushroom to grow in soil, outside the laboratory in a non-sterile environment, was the trick.

“Cross referencing a few scientific disciplines, plus observation of nature, a little common-sense and a bit of Kiwi ingenuity got me there.”

The mycelium, a white product of the oyster mushroom which seeks wood to disintegrate and eat, forces the roots of the mushroom to go further into the ground to find a source, eliminating DDT as it burrows deeper.

The oyster mushroom has had the most success so far, so now he has decided to ‘train’ oyster mushrooms by allowing them to adapt in small portions of the plot for longer.

He induces them with vitamins and natural enhancers which allows the mycelium to eradicate the pesticide over time.

Mr Lyon’s first attempt with oyster mushrooms in late 2009 failed, because of biological competition with native mushrooms.

However he says he lowered the DDT levels by a small percentage, although he lacked funds for a proper test and could not be certain.

The Wellington City Council has funded him since then, with its parks and gardens department donating truckloads of mulch and bark over the last two years.

Community engagement and reserves manager Myfanwy Emeny says the council paid around $600 to Hill Laboratories  for soil testing, and paid around the same amount for testing before the project began.

“We [the council] supported this trial as the land has previously been used as a bowling green and the council confirmed through independent testing that the soil contained pesticide residues, in particular low residues of DDT.

“This is public land, and it was seen as a worthwhile project if the Innermost Garden group could de-contaminate the soil and restore the land.”

The 2010 results of the tests were positive.

DDT in the garden area, which is 34 sq m, had dropped by 65% to 80%, and is now healthy enough to grow vegetables for the community.

The eventual outcome is to get the mushrooms strong enough to fend for themselves in a non-sterile environment.

“If the vegetables are grown in healthy soil, the plants themselves are healthier, so they can defend themselves against insects and disease attacks. It all starts with the soil,” Mr Lyon says.

The garden area he is experimenting on was originally a lawn bowls club which was annually sprayed with chemicals to reduce worms and insects.

The residual poison of the DDT is what Mr Lyon plans to eventually eradicate.

It is a long process, but one which would be much cheaper and eco-friendly than the expensive products and machines used currently.

“I’m not aware of anyone in the world developing a cheaper, more natural way that anyone could do. I’m trying to show there is hope for more natural ways to clean our environment.”

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