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This shows one more example of how easy it is for hormone mimic effects
to be unanticipated and even to be difficult to find when being
specifically looked for. This throws into question the USEPA review of
commercial chemicals as to their hormone mimics effects. How could such a
process ever actually uncover all or even most of such developmental
effects? My bet is we will be continually surprised over time at what
regulators and manufacturers failed to anticipate. [Much less the ignored
effects].
This effect seems obvious once it is mentioned, yet the researches said it
surprised them. This points out the need for even more training and
attention to total systems thinking.
And it is about time we stopped blameing the seals!
David Wimberly
ag487@chebucto.ns.ca
Halifax, Nova Scotia
http://www.geocities.com/RainForest/6847/
A new scientific truth does not triumph by convincing its opponents
and making them see the light, but rather because its opponents
eventually die and a new generation grows up -- Max Planck
*******************************************************************
Wednesday, January 13, 1999
The Halifax Herald Limited
Budworm spraying may be deadly to young salmon
By Chris Morris / The Canadian Press
Fredericton - Scientists have discovered what could be a major clue to
solving the mystery of the disappearing Atlantic salmon.
The same broad class of chemicals suspected of causing gender bending
in certain animals may also be fouling the salmon's ability to change
from freshwater to saltwater fish.
That would explain why seemingly healthy young salmon leave their
spawning rivers and then simply vanish at sea, a mystery that has been
attributed to everything from hungry seals to global warming.
A new study by researchers with the federal Department of Fisheries
and Oceans and Environment Canada has found that past spraying
programs against the spruce budworm may have knocked off more than the
tree pest.
A fisheries scientist in New Brunswick - which sprayed heavily against
the budworm for years - said Tuesday the study demonstrates a
relationship between chemical use and salmon survival, thereby
introducing another factor in the battle to save the wild fish.
"Salmon have to change from a freshwater to a saltwater fish and
there's a whole process of development that could be influenced by
changes in hormones," said Wayne Fairchild.
"What if the chemical exposure did something to influence juvenile
salmon just as they were going out to sea? When we did the study, to
our surprise, all the data that we had between forest spray exposures
and salmon populations started lining up. On one river, we saw a
linear relationship, a straight line between how much was sprayed and
how many fish came back."
Fairchild was alerted to a possible connection between gender-bending
chemicals and dwindling salmon stocks when he heard about the alarming
discovery of male trout with feminine traits in British rivers.
Gender-bending compounds, known as endocrine disrupting chemicals, can
alter hormones in animals and give males female characteristics. One
of the most famous gender-bending pollution cases involves an area in
Florida where male alligators have been discovered with penises much
smaller than normal.
Fairchild knew from previous studies that the budworm spray program in
Atlantic Canada, home to some of world's most storied salmon rivers,
included high concentrations of a compound called nonylphenol, which
mimics the female hormone estrogen.
Provinces such as New Brunswick, Newfoundland and Nova Scotia sprayed
against the budworm for years, using nonylphenol in the pesticide mix
from the mid-1970s to the mid-80s.
Fairchild said that even though there's no longer a budworm spray
program, hormone-disrupting chemicals are still getting into the
environment through sewage treatment and industrial effluent.
The widespread use of birth control pills is spilling into the
environment through sewage, he said.
"The current relevance is that the concentrations we were looking at
after forest spraying are not far from concentrations you can see in
industrial and municipal sewage treatment effluents today," he said.
Fred Whoriskey, vice-president of research with the Atlantic Salmon
Federation in St. Andrews, N.B., said the chemicals appear to disrupt
the salmon's ability to move from fresh to salt water, a transition
critical to the salmon's life cycle.
"The hypothesis is that these endocrine chemicals that are coming
through are affecting those little salmon and they're doing fine in
fresh water but when they hit the ocean, they disappear."
But Whoriskey doubts hormone confusion is the sole and final answer to
the mystery of declining Atlantic salmon populations.
"It can't be the only answer," he said. "There are very few places
where we have the answer. It's a combination of answers; it's
cumulative impacts that are causing these declines. We can't point to
one smoking gun and say that's the only one."
Atlantic salmon numbers declined sharply in most of Eastern Canada's
500 or so salmon rivers in 1997. The 1998 numbers are still being
tabulated.
The fish has been in trouble for years due to habitat destruction and
overfishing, but scientists have long believed something else was
happening at sea to further deplete stocks.
[2] Back
_________________________________________________________________
Copyright © 1999 The Halifax Herald Limited
_________________________________________________________________
References
0. http://www.herald.ns.ca/cgi-bin/home/altdisplaystory?1999/01/13+198.raw+altCanada
1. http://www.herald.ns.ca/cgi-bin/home/altsecfront?1999/01/13+altCanada#198.raw
2. http://www.herald.ns.ca/cgi-bin/home/altsecfront?1999/01/13+altCanada#198.raw
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