See also: Pesticide monitoring in Tasmanian water catchments.
Rigorous scientific analysis of water samples during February 2005 from the George River catchment at St Helens - taken at the same time and the same locations as those used by Dr Marcus Scammell - has found no man-made chemical of any sort.
Toxicity testing carried out by the Analytical Services Tasmania laboratory at the University of Tasmania revealed only natural compounds you would expect to find in any untouched, remote Tasmanian river.
Bottom and surface samples from all locations did not prove toxic to the tiny freshwater crustacean Daphnia (which is highly sensitive to a broad range of pollutants).
Only concentrated surface scum proved toxic to Daphnia. These samples were analysed and found to contain terpenes, fatty acids and aromatic ring compounds. These are naturally produced by native vegetation such as ti-tree and eucalypts. The fatty acids are what give wild streams the scummy foam which sometimes builds up near river eddies or floats on quiet stretches.
These organic compounds are common and natural. They are widespread throughout Tasmania because they are produced by native forest.
The results of the chemical and toxicity analyses as reported by Analytical Services Tasmania (AST) Laboratory: