Posted by Larry Hoover on December 15, 2003, at 8:34:05
In reply to farmed fish info, not complete but informative, posted by joebob on December 14, 2003, at 11:20:03
> it will take me time to find the info i want and my family would like some attention now, more later
>
> joebobI'm happy to take part in this discussion....I used to work for the World Wildlife Fund Environmental Toxicology Program, so I feel pretty qualified to assess the available information. Some text on the net is a little inflammatory.
> New scientific studies raise concern over toxicity of farmed fish feed
> Press Release David Suzuki Foundation 3jan00
> VANCOUVER, CANADA - Startling new scientific evidence....It's not startling, and it's not new.
> The research shows that the contaminants, known as persistent organic pollutants, are especially dangerous for children, nursing mothers and pregnant women or women considering pregnancy.Right there is a total mis-statement. The research presents exposure data, but not a thing about risk. A sensational statement, without basis.
> The studies were conducted in Canada by Dr. Michael Easton for the David Suzuki Foundation
Easton studied four farmed fish. Small sample.
> and in Britain by Dr. Miriam Jacobs in conjunction with the U.S. Environmental Protection Agency.
Jacobs studied ten farmed fish. Small sample. You just can't generalize from that.
> "We are calling on the Canadian government to immediately heed these findings and to fund the next stage of research needed to determine the safety of farmed salmon and salmon feed for people who consume this fish regularly," said Jim Fulton, executive director of the David Suzuki Foundation.
The Canadian government is now, and has been, monitoring both farmed salmon and feedstocks (fish meal and crude (unrefined) fish oil) destined for terrestrial animal or farmed fish feeds, for those contaminants (and others).
See:
http://www.inspection.gc.ca/english/anima/feebet/dioxe.shtml
> "Our research, conducted by Dr. Easton, is a pilot study that examined a small sample size.
Four farmed fish. One wild fish had greater PAH contamination than did the farmed fish. Wild fish had higher toxaphene concentrations than did the farmed fish. Where is that information in the press release?
Chemosphere. 2002 Feb;46(7):1053-74.
Preliminary examination of contaminant loadings in farmed salmon, wild salmon and commercial salmon feed.
Easton MD, Luszniak D, Von der GE.
International EcoGen Inc, North Vancouver, BC, Canada. michael_easton@intl-ecogen.com
This pilot study examined five commercial salmon feeds, four farmed salmon (one Atlantic, three chinooks) and four wild salmon (one chinook, one chum, two sockeyes) from the Pacific Coast for PCBs (112 congeners), polybrominated diphenylethers (PBDEs - 41 congeners), 25 organochlorine pesticides (OPs), 20 polycyclic aromatic hydrocarbons (PAHs), and methyl and inorganic mercury. The farmed salmon showed consistently higher levels of PCBs, PBDEs, OPs (except toxaphene) than the wild salmon. The mean concentrations in pg/g were 51,216 vs 5302 for total PCBs; 2668 vs 178 for total PBDEs; 41,796 vs 12,164 for total OPs (except toxaphene). The farmed salmon levels are likely a consequence of the elevated level of contamination found in the commercial salmon feed (mean concentrations in pg/g were 65,535 for total PCBs; 1889 for total BPDEs; 48,124 for total OPs except toxaphene). Except for a single high wild chinook value, PAHs were highest in the feed samples followed by the farmed fish and the three other wild fish. The Bio-Oregon-1996 feed of hatchery origin showed a level of PAHs ten times higher than any other feed. The genotoxic implications of such a high PAH level are considered for juvenile chinook salmon. Toxaphene and methyl mercury concentrations were not notably different between the wild and farmed salmon. There was no clear low contaminant brand of salmon feed. The human health implications of eating farmed salmon are considered from the perspective of the current WHO and Health Canada (2000) tolerable daily intake (TDI) values for PCBs. Based on a TDI of 1 pg TEQ/kg bw/day, this analysis indicated a safety concern for individuals who on a regular weekly basis consume farmed salmon produced from contaminated feed.
> But the results demonstrate reason for concern and the need for further study. We believe it is now the responsibility of the federal government to fund research that can shed more light on these findings," he added.Valid. But they already study the situation.
> The research by Drs. Easton and Jacobs shows the farmed fish sampled contained much higher levels of pollutants, including 10 times more Polychlorinated Biphenyls (PCBs), than wild fish. Their studies were conducted independently of each other.
To put these findings into historical context, PCB contamination of fish (and of all foods) has been falling for 20 years. It is not a new problem. It is an old problem, getting better.
See:
http://www.foodstandards.gov.uk/science/surveillance/fsis-2000/4diox
> "The results were very, very clear," Dr. Easton, a Vancouver-based geneticist and expert in ecotoxicology, told the British Broadcasting Corporation in a television documentary to be aired this Sunday (Jan. 7) in Britain.All results are clear. Interpreting is the hard part.
> "Farmed fish and the feed that they were fed appeared to have a much higher level of contamination with respect to PCBs, organochlorine pesticides and polybrominated diphenyl ethers than did wild fish. In fact, it was extremely noticeable," he said.Selectively noticed, IMHO, vis a vis toxaphene and PAH contamination of wild-caught salmon. PAHs (polycyclic aromatic hydrocarbons) are potent carcinogens arising from incomplete combustion.
> "It is a function of how the feed is made, of their concentrating of these different materials to produce high-protein diets for the fish and ultimately the contaminants apparently get concentrated as well," Dr. Easton said, adding that these pollutants affect the nervous system, the immune system and can cause cancer.But not at the concentrations found in these studies.
> "They're a neural toxin, which causes learning disabilities (especially in children) but they are also an immuno toxic," he told the BBC. "They cause depression of the immune system that enables you to catch colds and flus and infections much more easily than normal, and they also aid the production of cancer."
There is substantial debate in the scientific community about how to determine the "safe" intake level of a known toxin. The most recent scientific "attitude" has been to set those limits much much lower than the evidence would suggest is the toxic threshold. Generally, that is 1/100, or 1%, of the known toxic threshold, as seen in the most sensitive individuals. In some cases, it is set at 1/1000.
In historical terms, any presently published studies showing health benefits from fish consumption, particularly those showing long-term benefits from lifetime fish eating, present data involving fish far more contaminated with PCBs and dioxins, and dibenzofurans, and organochlorine pesticides (e.g. DDT) than are found today. The whole population of fish-eating people has already been the "guinea pigs" for the pollution experiment.
> Dr. Jacobs, a toxicologist in the School of Biological Sciences at the University of Surrey (U.K.), told the BBC: "I am concerned about the dietary intake of small children and infants. Their dietary intake will be far greater than for an adult based on body weight. An ongoing study in Holland has been monitoring for background levels of PCBs in very young children and up to school age, and it has been found that there is a greater risk of infection and a greater risk of impairment of cognitive development in those children that have higher intakes of PCBs."I don't mean to trivialize these findings, but the problem is getting better, not worse. I'm totally glad we're paying attention, but I don't like the sensationalizing of the issue.
> While the contaminant levels discovered by Drs. Easton and Jacobs were below government-approved safety levels, both scientists said they are concerned for people who regularly eat farmed salmon, and also about how governments establish risk-assessment values for human consumption of chemicals and pollutants.There is substantial debate over this, but even still, these supposedly contaminated fish (all food is contaminated....please believe that) fall below government-approve safetly guidelines. The food is safe to eat. It is simply being scrutinized.
> The BBC program Warning from the wild: The price of salmon especially raises questions about British Standards, which are far weaker than those of the World Health Organization (WHO) and other European countries which are following the newly established WHO standards. A spokesman for Britain's Food Standards Agency says they only recommend a person eat one portion of farmed salmon a week.Few people would eat more than one meal of farmed salmon a week, in any case. British dairy products, eggs, meat.....they're full of PCBs too, and dioxins.... Everywhere you look....
Fish is good for you. Unless you know it was caught from an especially contaminated body of water.
> "Once again, we have so many questions raised by scientists about this industry," Mr. Fulton said. "What we want from the Canadian government is that they fund additional scientific investigation. We are a small research agency and we cannot afford to conduct the next stage of research which is estimated at approximately $800,000."The monitoring programs already exist.
> Those funds could be found in the office of Canada's Aquaculture Commissioner whose office has an annual budget of over $2 million, Mr. Fulton added.
>
> "I presume that some of the work his office should be doing is this type of scientific research so I look forward to speaking to the Minister of Fisheries (Hon. Herb Dhaliwal) about the possibility of continuing Dr. Easton's work," he said.I have no problem with independent researchers getting involved, but I can assure you there is substantial interest in the academic community already. Funding through NSERC alone is in the tens of millions of dollars already.
Just my (perhaps too) informed opinions,
Lar
poster:Larry Hoover
thread:287116
URL: http://www.dr-bob.org/babble/alter/20031204/msgs/289961.html