The levels of heavy metals - including mercury, cadmium and arsenic - did not exceed thresholds considered dangerous, the investigators found.
However, 16 of the 40 supplements tested contained pesticide residues that appeared to exceed legal limits, the investigators found.
In some cases, the government has not set allowable levels of these pesticides because of a paucity of scientific research.
The letter 'b' of trombone was created by Ben Gerstein, using a xerox copier as his Medium. His subject matter is a page from the book "The Counterfeiters" by Andre Gide. Of special significance is the word "trombones" in the text, as Ben Gerstein is himself a trombonist.
With each copy, on each page, the letter evolved.
The result was a stunning fractal pattern, generated by the copier itself, lasting for around 165 pages. Clever positioning of each page allows us to delve ever deeper into the pages on our journey through the letter B.
Troubling times: The ongoing euro woes and a new threat of military action between South Korea and North Korea saw Asian markets fall, with the FTSE following suit yesterday
The US secretary of state has been pressing China to join the international condemnation but Beijing is taking a cautious line, calling for restraint, our correspondent says.