Following the cleaning of the bottles,a waste sludge is produced that Coca-Cola have been disposing of on the land of local farmers,claiming it was a useful fertilizer.Follwing a BBC Radio 4 program,samples of the sludge were analyzed by scientists at Exeter University in the south-west of England and found to contian toxic chemicals including lead and cadmium-both of which can be harmful to humans-and further suggested that there was little or no benifit of the sludge as a fertilizer.Recent tests by the local state laboratories find that the levels of toxic chemicals are within safety levels but that it should not be used as a fertilizer.