Teens wow scientists with wood study

23:00, Nov 08 2012

Two teenagers have impressed scientists with their research into the effects of a widely used timber treatment that can leach toxic chemicals into soil - publishing their study while still at high school.

Palmerston North Girls' High year 13 pupils Eleanor Pepper and Apurva Kasture, both aged 17, received a team Gold CREST from the Royal Society of New Zealand for their project which investigated chromated copper arsenate-treated pine fence posts at vineyards.

CCA is a wood preservative that has been used for treatment of perishable timber such as pine since the mid-1930s. The treatment gives wood a greenish tint, is widely used at regulated levels in the construction industry and was once a familiar feature of children's playgrounds.

In high concentrations copper and arsenic are toxic and chromium is a known carcinogen.

The girls were anxious to say that the chemicals did not affect the tipple that finished up in wine bottles.

They were more concerned with the health of the soil used to grow the valuable grapes.


"If it leaches out into the soil you can see how it could have quite a drastic effect on living things," Apurva said.

The girls had approached Plant and Food researchers for help in their investigation.

But as they were not allowed to handle arsenic due to their tender age, experts directed them to fence posts instead.

"It would make more sense for a vineyard owner or farmer to know about their soil health rather than the concentration of arsenic," Eleanor said.

To test how much of the chemicals were leaching into the soil, they compared the difference in the soil around posts installed at a Marlborough vineyard in 1991 and in 2003.

"We did some research and we found that the grapevines and the grapes are not affected by CCA chemicals but if the health of the soil is compromised plants are getting less nutrients and they are not able to grow as well, potentially," Apurva said.

Plant and Food science group leader Dr Brent Clothier was impressed with their findings.

"I'm amazed and impressed at their enthusiasm around their research; they worked hard and they were certainly rewarded," he said.

Marlborough's Yealands Estate Wines owner Peter Yealand, who runs a sustainable vineyard, said organic grape growers were required to replace broken posts with untreated wooden, plastic or steel posts.

"If I was going to do it all over again I would use untreated timber, if I could get it at an affordable price," Mr Yealand said.

European growers used a hard wood which was not as affordable or readily available as New Zealand-grown pine. "The reason most people prefer to use a wooden post is because it has more body and substance in the ground and doesn't tend to tip up in the wind."

Manawatu Standard