Hi Mike,

I've only read a little regarding recent uses of DDT & the impacts on
birds (my understanding is that in developing countries the chemical is
not being broadcast-sprayed on crops the way it was here, but rather
applied to clothing & mosquito netting as a preventative measure, so
it's applied in smaller quantities--if others know more about this
please let me know).  I will say that it might not be too surprising
that eggshell thinning is still a problem among bird species.  DDT is a
pervasive chemical that has a very long half-life.  In March of 2006,
the USGS released a statement regarding pesticides in U.S. streams &
ground water.  They found that DDT was "frequently detected in bed
sediment and fish in urban and agricultural areas. Concentrations of
these compounds in fish declined following reductions in their use
during the 1960s and elimination of all uses in the 1970s and 1980s, and
continue to slowly decline. Just as notable as the declines, however, is
the finding that these persistent organochlorine pesticides still occur
at levels greater than benchmarks for aquatic life and fish-eating
wildlife in many urban and agricultural streams across the Nation."
  
Additionally, DDT is showing up in surprising concentrations in arctic
ponds and lakes, where DDT was never used.  They're finding seabirds,
like Northern Fulmars, that nest near inland arctic ponds are
sequestering DDT, mercury, and other pollutants they are exposed to at
sea, and then releasing these chemicals into the arctic ponds through
their droppings.  The researchers have said, "the effect is to elevate
concentrations of pollutants such as mercury and DDT to as much as 60
times that of areas not influenced by seabird populations."

I'm not really sure I answered your question, but hopefully this
information helps a bit.

Thanks,

Casey

Casey Tucker
Education Specialist
Audubon Ohio
692 N. High St., Suite 303
Columbus, OH 43215
614-224-3303 (phone)
614-224-3305 (fax)
[log in to unmask]
www.audubonohio.org
 

-----Original Message-----
From: Mike Busam [mailto:[log in to unmask]] 
Sent: Thursday, February 01, 2007 4:43 PM
To: [log in to unmask]
Subject: DDT questions

Greetings.... I wanted to ask a couple questions of the list regarding
DDT. 
It was blamed for a lot of the problems effecting birds in the 50s
through 
the 70s or thereabouts. The banning of DDT in North America is often 
credited with allowing the comeback of Bald Eagles, Peregrine Falcons,
and 
other raptors.

DDT is also an excellent malaria fighter, and today malaria remains a
deadly 
problem in large portions of the world.

My understanding is that DDT is still used throughout the world, but not
as 
much as some say it should be. I've read various op-ed pieces which
claim 
that DDT effects upon birds are exaggerated if not untrue, and they
claim 
that research proves this. I'm not aware of what studies they are
citing, 
though, and op-eds that claim Rachel Carson is responsible for more
deaths 
than Hitler and Stalin combined make me a bit suspicious of both the
angle 
of the writer and the source material. I've also heard people who work
with 
raptors argue that egg shell thinning problems, which they attribute to
DDT, 
remains a problem for birds such as Bald Eagles and Osprey. I remember
an 
ODOW supervisor commenting in Cincinnati a few years back that egg shell

thinning problems still occur in a number of Bald Eagle nests around
Lake 
Erie.

So I was wondering if anyone on the list has read through any of the new

literature about DDT, which supposedly supports the argument that it is
not 
harmful to birds and wildlife. Where are the various researchers coming
down 
on the effects--both positive and negative--of DDT? Is the pro-DDT
research 
by reputable sources; has it been peer reviewed, tested, etc.?

Take care,
---Mike Busam
West Chester, OH