Teens study CCA use in vineyards

22:30, Nov 08 2012
Eleanor Pepper
In print: Eleanor Pepper, left, and Apurva Kasture with treated pine used in fencing and construction. Their research on a Marlborough vineyard focused on the chemicals used in treating the wood.

Two Palmerston North teenagers have impressed scientists with their research on a Marlborough vineyard into the effects of a widely used toxic timber treatment.

The girls have published their study while still at secondary school.

Palmerston North Girls' High School year 13 students Eleanor Pepper and Apurva Kasture have received a team Gold Crest from the Royal Society of New Zealand for their project which investigated pine fence posts treated with chromated copper arsenate to use in vineyards.

Chromated copper arsenate, also known as CCA, is a wood preservative used for treating softwood timber such as pine since the mid-1930s. It 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.

Copper and arsenic are toxic in high concentrations and chromium is a known carcinogenic.

The girls believe the chemicals do not leach into the vines to affect the finished wine. They were more concerned with the health of the soil used to grow the 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. The specialists said the girls were too young to handle arsenic and suggested they focus on treated 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 grape vines 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," 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.

Yealands Estate owner Peter Yealand, who runs a sustainable vineyard in Marlborough, said organic grape growers are required to replace broken tanalised 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," he said. Hardwood is used by European growers.

The Marlborough Express