The only black spot for Canada during the final weekend of the Pan American Games was the news that water skier Aaron Rathy failed a drug test and was stripped of his wakeboard silver medal won at Boca Laguna on the shores of Lake Chapala.Games doping officials said Rathy had tested positive for the stimulant methylhexaneamine.

In a written statement by Canada’s Water Ski Association, Rathy apologized and explained that he had bought the nutritional supplement Oxy Elite Pro from a GNC store without realizing that it contained the banned substance.

On its website, Oxy Elite’s manufacturer advises athletes to check with their federations before taking the supplement.