Chicken droppings could help clear up oil spills

Chicken droppings may be one answer to cleaning up soil contaminated with crude oil, according to researchers in China.

Soil that has been ploughed with chicken manure breaks down 50 per cent more crude oil than soil lacking the manure, according to a team led by Huiwen Ma, a professor of biochemistry at China's Wuhan University.

The contamination of soil by crude oil is a growing problem as China accelerates its exploitation of oil reserves to meet rising energy demands. The fifth largest oil producer in the world, China produced 190 million tons of crude oil in 2008.

But the environment has paid a huge price. The Zhongyuan oilfield in Henan has polluted over 1,700 hectares of adjacent farmland, according to a preliminary calculation by Henan Agricultural University in 2002.

Previously, scientists have applied chemical fertilisers to the soil to encourage microbes to degrade the oil. But the fertilisers are expensive, can threaten the environment themselves and also cause the soil to harden and become less fertile.

In their laboratory experiment Ma's team found that a Bacillus species found in chicken manure is the most effective oil-removing microbe.

The manure decreases the acidity of soil, creating an environment ideal for the bacterial degradation.

The chicken farms that have sprung up over China in recent years have made accumulating chicken manure a more realistic prospect, said Zhang Zhongzhi, a professor of biochemical engineering from the China University of Petroleum. Ma's research offers a pragmatic approach to biodegradation, he told SciDev.Net.

But Ma said that, in the field, the manure will take longer to work because of differences in oxygen supply and fluctuating temperatures.

The study was published in the International Journal of Environment and Pollution in February.