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 antibiotics.

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 levels of antibiotics in all 58 river basins across the country.

The study found that the average antibiotics levels in river basins of the densely populated, economically developed eastern and southern China were more than six times higher than in less developed western China.