BLOOMINGTON, Indiana, August 10, 2004 (ENS): Farmed salmon
are contaminated with much higher levels of chemical
flame retardants than most wild salmon, new research
Ronald Hites, distinguished professor at Indiana University
and lead researcher on the study, studied polybrominated
diphenyl ethers (PBDEs), a group of flame retardant
chemicals used in electronics, upholstery, and other
consumer products. He determined that the contamination
is linked to the high fat diet that farmed salmon are
Wild salmon eat a diverse diet of aquatic organisms,
but farmed salmon are fed a high fat diet of ground
up fish and fish oil. Since chemical contaminants fish
are exposed to during their lives are stored in their
fat, the high fat food carries more contaminants to
the farmed salmon.
"PBDEs are structurally similar to PCBs, which
have been linked to cancer and to reproductive, neurological,
and developmental effects in humans," said Hites.
"Even though no quantitative risk estimates have
been done for PBDEs, public health experts are concerned
because the concentrations of these substances in people
have been increasing so rapidly."
The Pew Charitable Trusts sponsored the study. Pew
has sponsored major research on fisheries, including
a number of widely reported recent studies on the deterioration
of the marine environment.
The study published this week in the journal "Environmental
Science and Technology" concludes that, in spite
of the heart healthy benefits of omega-3 fatty acids
in all salmon, frequent consumption of farmed salmon
is more likely than wild to boost levels of PBDEs.
The amounts of PBDEs detected in people and wildlife
appear to have doubled in North America every four to
five years since the 1970s, a pace unmatched by any
other contaminant. Electronics companies including Sony
and Toshiba and at least one major furniture maker,
Ikea, have phased out PBDEs from their products.
The data on PBDE concentrations in farmed and wild
salmon come out of the world's largest scientific sampling
of salmon yet published in a recognized peer-reviewed
The study analyzed fillets from about 700 farmed Atlantic
salmon and wild Pacific salmon. The farmed salmon was
produced in each of the eight major farmed salmon producing
regions in the world or purchased in 16 large cities
in North America and Europe. The study's authors, six
U.S. and Canadian researchers representing fields from
toxicology to biology to statistics, selected salmon
samples to be representative of the salmon typically
available to consumers.
While wild salmon as a group were generally the least
contaminated with PBDEs, PBDE concentrations were highest
in wild Chinook from British Columbia and in farmed
salmon from Scotland and Western Canada.
The lowest concentrations of PBDEs were found in the
other wild salmon and in farmed salmon from Chile and
Washington State. The level of PBDEs in the salmon appear
to be related to what the fish eat.
One unusual finding involved the relatively high PBDE
concentrations in the wild Chinook samples. The authors
found significant and unexpected differences in PBDE
concentrations among the different species of wild salmon
suggesting that different feeding behavior - for example,
chinook tend to feed higher on the food chain - and
other biological differences among the species could
account for these differences.
The British Columbia Salmon Farmers Association says
the levels of flame retardant are so low, people who
eat farmed salmon are not in danger. "While PBDEs
are present in many fish in North America, there is
no evidence to suggest any harm to humans from eating
fish with the very low levels reported," the association
"The difference in levels found in wild or farmed
fish is recorded in parts per billion and the levels
reported are very low." said Mary Ellen Walling,
executive director of the B.C. Salmon Farmers Association.
"There are two important things for consumers
to know," Walling said. "First and most importantly,
both wild and farmed salmon are a healthy and nutritious
food with significant health benefits. And secondly,
even though wild B.C. Chinook had the highest levels
reported, there is no meaningful difference between
the levels found in wild and farmed salmon. Both are
Fresh water fish such as striped bass and mountain
whitefish were found to generally have higher levels
of the flame retardant chemicals than salt-water species,
The salmon farmers' association has a lot to lose if
consumers begin to believe that farmed salmon are not
safe food. British Columbia, Canada's largest aquaculture
producing province, generated sales of C$329.6 million
in 2002, up 12.3 percent from 2001.
The findings released this week expand on a January
study published in the journal "Science" which
found that farmed salmon contained higher levels of
cancer causing PCBs, dioxins, and some pesticides than
did wild salmon.
That study concluded that concentrations of some contaminants
were so high that more than one meal of farmed salmon
per month could pose unacceptable cancer risks. The
majority of salmon served in restaurants and found on
grocery store shelves is farmed rather than wild.
Beginning next month, U.S. supermarkets will be required
to label salmon farmed or wild along with country of
origin under a 2002 law. Salmon purchased in restaurants
and fish markets are not covered by this law.
Consumers should be aware that the word "Fresh"
on the label does not mean the salmon is wild-caught
from the ocean. And any salmon labeled "Atlantic"
in the U.S. is almost always farmed because wild Atlantic
salmon are rare and endangered.
Copyright Environment News Service (ENS) 2004. All