Re: agent orange's fingerprints

[Lew Baker <lab1@ezwv.com>]

Dennis, thanks for the tip on New Jersey.  I've loooked at published data
for sediment downriver of Diamond Shamrock's agent orange site there.  As I
recall, it was not congener specific, but seemed to indicate a very high
tcdd contribution to total teq in the sediments.  Surely there's more data
there, that I haven't seen yet.

Congener/isomer specific sediment data for the Kanawha River below Monsanto
in WV has had from 50-90% teq from 2,3,7,8 tcdd.  The river's water has been
reported at 50% teq from 2,3,7,8 tcdd, but its fish have 90-100% of their
dioxin teq from 2,3,7,8 tcdd.

Fish lipids do bioaccumulate this most toxic form of dioxins/furans more
readily than the others, hence the shift in the congener "fingerprint".  I
have found the fish lipids to generally be more consistent from sample to
sample, than the sediment and water samples.  The later are prone to vary in
space and time, with the seasons and with stream flow.  Each fish has a
composite sample in its lipids, and fish samples are usually a composite of
4 or 5 fish. There are also more fish lipid data available for the Kanawha
and Ohio Rivers than for the other media.

Perhaps most importantly, the primary threat of these contaminants to humans
and other members of the food chain IS the food chain (i.e. the lipids).
The threat from drinking the water or otherwise ingesting the sediment is
negligible.  For example, the average total dioxin teq for fish lipids from
the 40 miles of Kanawha River below Monsanto is 981 pg/g (942 pg/g from
2,3,7,8 tcdd), whereas the water usually has less than 1 pg/l tcdd.  It
would be easy to consume a gram or so of fish fat per day, but impossible to
drink 1000 liters a day.

At least for these rivers, the fish data is the most meaningful for
estimating risk.  They also contain the most complete and dependable
"fingerprints".

Lew Baker
--------------------------

Catalano, Dennis wrote:

> Fish are a bit tricky to "fingerprint" in that the rate of
> bioaccumulation varies from congener to congener as well as isomer to
> isomer.  One of the reasons why non 2,3,7,8-substituted isomers are less
> toxic is that they don't bioaccumulate.  As far as other agent orange
> data, you may want to check with the State of New Jersey.  I was
> involved several years back on a study that may be published at this
> time.  I am not at liberty to give any other information at this time
> about the results, but they may be public record.
>
> Dennis Catalano
>  ----------