Ottawa urged to take stronger action on cadmium health concerns in B.C. oysters: expert
By Larry Pynn, Vancouver SunDecember 14, 2010
Government and industry are putting economics ahead of public health when it comes to addressing the issue of cadmium levels in B.C. oysters, a biology professor at Simon Fraser University charged Monday.
Leah Bendell, a specialist in ecotoxicology (the study of contaminants in ecosystems), has been studying cadmium in shellfish for a decade and says Ottawa cannot continue to ignore the growing health threats from cadmium. Governments need to bring in stronger guidelines for consumption, she said.
"It's reached the point, enough already," she said. "Cadmium is becoming a global issue. It's on the radar. It's a concern.
"People should really know so they can make an informed choice."
Cadmium is a naturally occurring element that can cause kidney and bone problems if ingested over long periods, reports the BC Centre for Disease Control. It has also been linked to other health problems such as diabetes and high blood pressure, although the scientific evidence to date "is not strong."
In a paper published recently in the journal Toxicology Letters, Bendell wrote: "It is clear that at this time industry and government are making choices based on the economics of the dilemma, rather than the protection of public health for which both federal and provincial governments are responsible."
She argued that health concerns associated with cadmium in shellfish are often played down -- or not mentioned at all -- on various shellfish aquaculture websites of the senior governments as well as the B.C. Shellfish Growers Association.
"It is simply not considered an issue by either industry or government," Bendell wrote. "To do so would threaten the development of this economy in coastal communities that desperately need access to some means of employment and revenue."
Stephane Shank, media relations official for Health Canada, said in response that the federal department in 2002 issued consumption advice specifically for B.C. oysters: A limit of 460 grams per month for adults (about 12 oysters), and 60 grams per month for children (about 1.5 oysters).
Ottawa is in the process of reviewing the latest scientific information on cadmium toxicity and data to determine if any changes are warranted, Shank said.
Bendell said the Canadian consumption advice barely meets international standards and does not take into account that cadmium levels are higher in "hot spots" in popular oyster-growing areas such as Baynes Sound near Denman Island, Desolation Sound north of Powell River, and Effingham Inlet at Barkley Sound.
She urged oyster growers to move to coastal areas known to have lower cadmium levels, adding the province should compensate them.
Current guidelines also fail to consider that consumers might be getting cadmium from other sources, including from smoking or other dietary sources, she said.
Groups at higher risk include women with low iron levels, people with renal impairment, smokers, children, and aboriginals who consumer greater amounts of seafood.
One study in 2000 found B.C. oysters reached levels as high as 4.9 parts per million, while a 2004-05 study found levels of up to 3.57 parts per million. A workshop sponsored by SFU in May estimated current cadmium levels in B.C. oysters at one to four parts per million.
Europe does not allow the importation of oysters containing more than one part per million of cadmium compared with Hong Kong's standard of two parts per million.
The BC Centre for Disease Control states that "levels of cadmium are much lower in oysters elsewhere in the world."
It said scallops are only a problem if consumed whole and that the "more commonly consumed adductor muscle (the fleshy part of the scallop) is low in cadmium." Most clams and mussels have low cadmium levels.
Matthew Wright, executive assistant with the Comoxbased B.C. Shellfish Growers Association, said cadmium is "found in everything from carrots to spinach and even in the air we breathe" and to attribute any adverse health effects to shellfish consumption is unfounded.
"People have been eating farmed shellfish from B.C. for over 100 years and there's never been one direct link to adverse health effects documented," he said.
Bendell said cadmium levels are much lower in leafy green vegetables and accused industry of an "absolute head-in-the-sand approach."
Shellfish aquaculture in B.C. is valued at about $37 million a year -- 40 per cent of that oyster production -- and employs more than 1,000 full-time workers.
lpynn@vancouversun.com© Copyright (c) The Vancouver Sun
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