Pete C. wrote:

>
> Mark Thorson wrote:
>>
>> "Pete C." wrote:
>> >
>> > Mark Thorson wrote:
>> > >
>> > > "Pete C." wrote:
>> > > >
>> > > > blake murphy wrote:
>> > > > >
>> > > > > what levels of added p.c.b.'s and toxic chemicals do you need before
>> > > > > the farmed fish aren't 'quite right'?
>> > > >
>> > > > Ones that are quantified and significant. As an example, the difference
>> > > > between 1 ppb and 3 ppb is "huge", "3X", "300%", but bloody irrelevent
>> > > > in the real world.
>> > >
>> > > In this study, PCB levels in salmon ranged from
>> > > 145-460 ppb. That's a huge amount!
>> >
>> > Again, incomplete data. Where is the data from the wild caught control
>> > samples? Without that data no meaningful conclusion can be drawn as to
>> > the alleged difference between wild caught and farmed product.
>>
>> But we know the numbers for farmed salmon, and
>> the numbers ain't good!
>>
>> This study gives numbers comparing farmed vs. wild,
>> and there's a huge difference, especially at the
>> high end of the range.
>>
>> Environ Sci Technol. 2006 Sep 1;40(17):5347-54.
>> PCBs, PCDD/Fs, and organochlorine pesticides in farmed
>> Atlantic salmon from Maine, eastern Canada, and Norway,
>> and wild salmon from Alaska.
>> Shaw SD, Brenner D, Berger ML, Carpenter DO, Hong CS,
>> Kannan K.
>> Marine Environmental Research Institute, P.O. Box 1652,
>> Blue Hill, Maine 04614, USA.
>>
>> Farmed Atlantic salmon (Salmo salar) from Maine and
>> eastern Canada, wild Alaskan Chinook salmon (Oncorhynchus
>> tshawytscha), and organically farmed Norwegian salmon
>> samples were analyzed for the presence of polychlorinated
>> biphenyls (PCBs), dioxin-like PCBs, polychlorinated
>> dibenzo-p-dioxins (PCDDs), dibenzo-p-furans (PCDFs), and
>> chlorinated pesticides. PCDD and PCDF congeners were not
>> detected in > 80% of the samples analyzed. Total PCB
>> concentrations (7.2-29.5 ng/g, wet weight, ww) in the
>> farmed salmon were significantly higher than those in
>> the wild Alaskan Chinook samples (3.9-8.1 ng/g, ww).
>> Concentrations of PCBs, WHO PCB TEQs, and chlorinated
>> pesticides varied significantly by region. PCB and WHO
>> PCB TEQ concentrations in farmed salmon from eastern
>> Canada were lower than those reported in samples
>> collected two years earlier, possibly reflecting recent
>> industry efforts to lower contaminant concentrations in
>> feed. Organically farmed Norwegian salmon had the highest
>> concentrations of PCBs (mean: 27 ng/g, ww) and WHO PCB
>> TEQs (2.85 pg/g,ww); their TEQ values are in the higher
>> range of those reported in farmed salmon from around the
>> world. Removal of skin from salmon fillets resulted in
>> highly variable reductions of lipids and contaminants,
>> and in some skin-off samples, contaminant levels were
>> higher, suggesting that skin removal does not protect
>> the consumer from health risks associated with
>> consumption of farmed salmon.
>
>
> What I see from that data is that levels in both are quite variable, and
> indeed some of the farmed samples had lower levels (7.2 ng/g) than some
> of the wild samples (8.1 ng/g).
>
> Showing just the high and low of a group of samples is misleading since
> you don't know what the distribution is. Those extremes may represent
> only one sample, and make it very easy to distort the data to fit an
> agenda. The only mean value given was for the organic farmed Norwegian
> samples.
>
> It's entirely possible that most of the samples from both groups were in
> the 7-8 ng/g range showing no difference between farmed and wild, or
> most of the wild near 4 ng/g and most of the farmed near 29 ng/g showing
> a huge difference.
>
> Again, it's incomplete data and subject to presentation in a manner that
> may be misleading. Either way we're talking about extremely low levels.

Well, you sure know how to screw up a nice bit of panic.

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