Making a case for cadmium/shellfish guidelines
Leah Bendell, 604.983.3249, 778.989.5560; bendell@sfu.ca (email best)
Carol Thorbes, PAMR, 778.782.3035; cthorbes@sfu.ca
Simon Fraser University biologist Leah Bendell views a science writer’s citation of her 2010 research in the December issue of Environmental Health Perspectives (EHP) as an early Christmas present.
M. Nathaniel Mead twice references Bendell’s research on the health hazards of consuming shellfish that contain elevated amounts of cadmium, a toxic metal.
Mead has been writing about science research for the EHP — a highly regarded international peer reviewed research journal — since 2002.
Bendell, an ecotoxicologist, has been researching the prevalence and health impact of naturally occurring cadmium in shellfish, particularly oysters and scallops farmed in the Pacific Northwest and off B.C.’s coast, for the last decade.
Bendell’s research acknowledges that seafood farmers and governments have invested millions of dollars in setting up shellfish aquaculture, a potentially important economic driver provincially and nationally.
But she also emphasizes that ongoing research runs counter to this vision, consistently showing that some shellfish have high levels of cadmium.
Bendell hopes that Mead’s quotation of her findings in Cadmium Confusion: Do Consumers Need Protection will motivate Health Canada and the B.C. Centre for Disease Control to toughen its stance on shellfish consumption guidelines.
“Consumers need to know exactly how much shellfish they can safely eat to ensure that long-term exposure to cadmium doesn’t jeopardize their health,” says Bendell.
“While B.C. has no regulations or recommendations on safe consumption of cadmium, Health Canada’s information is inadequate and incorrect. It doesn’t acknowledge the scientifically proven link between chronic exposure to cadmium and disease occurrence.
“There’s no reference to high risk groups, such as indigenous people, who are often already pre-disposed to cadmium related diseases such as diabetes and cancer.”
Mead uses research, including Bendell’s, to drive home why governments owe consumers the right to know and choose what level of cadmium they’re prepared to consume in their food.
Extensive international research indicates that even low levels of cadmium buildup in the human body can precipitate a whole host of diseases, including various cancers, kidney problems, bone loss and diabetes.
Bendell has found that cadmium concentrations in oysters and scallops along coastal B.C. can be two to 10 times higher than elsewhere in the world.
Mead references Bendell’s article Cadmium in shellfish: The British Columbia, Canada experience — a mini-review, published in the Apr. 24, 2010 issue of Toxicology Letters, an international journal. He also quotes information from a multi-stakeholder workshop, Cadmium in Shellfish from the Pacific Northwest: Status and Health Concerns, hosted by SFU’s Centre for Coastal Studies/Faculty of Environment on May 3, 2010.
The article and workshop participants discuss the need for more research on why shellfish farms in some areas, known as hot spots, take up more cadmium than in others. “We don’t really know why yet,” says Bendell.
Their conclusions call on the Canadian and B.C. governments to bring in safe cadmium consumption guidelines that match European levels. They also want health authorities to publicize known cadmium-induced health problems and implement a government regulated cadmium level monitoring system.
Mead uses several researchers' findings, including Bendell's, to argue that the U.S. Environmental Protection Agency should adopt and enforce shellfish farming practices, like Australia's.
Those minimize naturally occurring cadmium levels in ocean-based farming and follow Europe's stricter safe consumption guidelines for oysters.
European guidelines tie safe levels of cadmium ingestion to eating only one oyster a week. Meanwhile, international guidelines set by the United Nations and the World Health Organization — which Canada follows — consider consumption of three oysters a week to be safe.
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