News Coverage
Farmed Salmon Raise Concerns
Study Cites High Levels of Chemical Fire Retardants
Published August 10, 2004
Farmed salmon accumulate much higher levels of chemical flame retardants than wild salmon, according to a study published yesterday in the journal Environmental Science and Technology.
Flame retardants known as PBDEs have come under increased scrutiny as their level in human blood has doubled over the past five years. They are similar in structure to PCBs, carcinogenic chemicals once used as an insulators in electric equipment. In laboratory studies, flame retardants have been shown to impair development of young rats and rat fetuses and to disrupt their hormone systems, but there have been no similar studies in humans.
"I'm very concerned," said Jeffery A. Foran, one of the authors of the study and a professor at the School of Public Health at the University of Illinois at Chicago.
The study, funded by the Pew Charitable Trusts follows a January survey by the same group that showed farmed salmon had higher concentrations of PCBs and dioxins than wild salmon.
Europeans are taking a few flame retardants off the market as of Sunday because of health concerns, and California is banning PBDEs as of Jan. 1, 2008.
The levels of flame retardant varied according to where the fish was farmed, researchers found. European farmed salmon had higher amounts of PBDEs than North American salmon; Chilean farmed salmon had the least. Researchers sampled 700 farmed and wild salmon bought from wholesale suppliers as well as supermarkets.
Levels in farmed salmon ranged between 1 and 4 parts per billion, while wild salmon showed concentrations on average of 0.5 parts per billion. The one exception was wild chinook salmon from Oregon and the Canadian province of British Columbia, which had higher levels than some farmed fish. Researchers attributed this to the fact that the chinook are large and higher on the food chain.
The difference between wild and farmed salmon stems from their diet, researchers wrote: "Farmed salmon are fed a concentrated feed high in fish oils and fish meal, which is obtained primarily from small pelagic fishes." Wild salmon have a less fatty diet and get more exercise, according to Indiana University professor Ronald A. Hites, leaving less opportunity for flame retardant chemicals to accumulate.
Salmon of the Americas Executive Director Alex Trent, whose group represents salmon farmers in Canada, Chile and the United States, said the study would confuse consumers.
"When public health professionals examine this in the light of day, they'll come to the same conclusions we do. Is there anything at risk? No," Trent said.