Matthew Phan, Business Times 13 Mar 08;
(SINGAPORE) The toxicity of jatropha, a shrub touted as a potential source of biodiesel, poses challenges in terms of handling its oil processed, an expert said yesterday. Others disagreed.
Jatropha oil is "very toxic", Chevron's regional products technology manager for Asia-Pacific, Greg Engeler said at a Clean Energy Roundtable organised by the Singapore Environment Council and supported by Chevron.
"The health and safety issues associated with working at a plant are significant", he said.
However, other industry players contacted by BT yesterday disagreed. Peter Cheng, chief executive of Van Der Horst Biodiesel, which is aiming to plant over 150,000 hectares of jatropha to feed two large scale biodiesel plants, said the jatropha seeds and oil have "very little toxin content" and "even if swallowed in large quantities will cause diarrhoea but is not enough to kill".
Mr Cheng also said the emissions from burning jatropha biodiesel are non-toxic, as the toxins are destroyed by the combustion process. Nor is the oil poisonous to touch, he said.
The truth could be somewhere in between.
Jatropha oil contains "phorbol esters", a type of compound that in animal experiments has been found to incite cancer, according to Dr Hong Yan, director of Plant Biotechnology at the Temasek Life Sciences Laboratory (TLL).
The oil can irritate the skin on first contact, but is not immediately hazardous; however, "long term exposure might increase health hazards", he said.
It is a potential concern that has not yet become as problem, as no one has yet built a large scale jatropha biodiesel processing plant, said Dr Hong.
So, humans involved in jatropha oil pressing or biodiesel processing who come into direct skin contact with the oil over a long-term could face health hazards.
However, "there is no problem if there is no direct contact", and "it is still possible to build jatropha plants, you just need to be aware and exercise care and diligence", said the scientist, who spearheads jatropha research in Singapore, including a 1.7-ha experimental farm.
TLL is attempting to develop non-toxic strains of jatropha, said Dr Hong.
One approach, using traditional breeding techniques, could help produce a strain with far lower toxin content within two to three years, he said.
But TLL is also banking on mid to long term success with genetic engineering. "Sometimes toxins are necessary for the plant to defend itself against insects.
Ideally, you specifically knock out toxins in the seeds, but not the rest of the plant, so you get what you want with minimal effect on other agronomic characteristics", he said.
Meanwhile, Chevron is investing in research of third-generation biofuels from algae and wood, said Mr Engeler.
But it is still very early stages, as the calorie-rich oil produced by the algae is highly diluted by the water in which they breed, and requires large amounts of energy to extract, he said.
