BEIJING - A recent study paints an alarming picture of the levels of antibiotics in the river basins of China, the world's largest producer and user of the medications.

The study, started in 2006 by the Guangzhou Institute of Geochemistry under the Chinese Academy of Sciences, studied the discharge of 36 frequently detected antibiotics and built a model predicting the levels of antibiotics in all 58 river basins across the country.

It found the average antibiotics levels in river basins of densely populated, economically developed eastern and southern China to be more than six times higher than in less developed western China.

Northern China's Haihe River basin and the south's Pearl River basin were the most worrying, according to the study. The high antibiotic concentration in the Haihe River basin is due to the river's slow flow and low rainfall, which make it difficult to dilute the large antibiotics emissions from Beijing, Tianjin and Hebei province. The Pearl River basin had the highest level due to its large population and prosperous livestock breeding industry.

"Antibiotics in water and soil can enter the human body if people drink contaminated water or eat food grown with contaminated water," Dr Ying Guangguo, leader of the research team at the Guangzhou institute, said on Thursday.

"The biggest danger from antibiotics abuse and poorly treated antibiotics emissions... is increased bacterial resistance, which will make it harder for medicine to work effectively," he said. "The most appalling finding... is that some rural pig farms directly discharge faeces and urine into the river."

Dr Ying urged the government to increase supervision of hospitals, farms and sewage plants, and to monitor the concentrations of antibiotics in the most affected river basins as soon as possible.

CHINA DAILY/ASIA NEWS NETWORK