[pct-l] What I've learned about DEET - maybe it's not so healthy to be around"

[bluebrain at bluebrain.ca (bluebrain@bluebrain.ca)]

I hate to play the devil's advocate, but has anyone considered that
something that melts plastic might not be particularly healthy to be
around?  Particularly when you're talking about weeks or months of
exposure on a long distance hike, not two days of exposure on a camping
trip.

This came up a while back on trail-forums so I did a bit of research.

Deet is a toxic pesticide, it?s just not rated to be toxic enough to have
any significant health implications when used correctly.

I?ve read the EPA reports as well. They indicate that exposure to children
should be carefully limited and adults should avoid concentrations higher
than 30%. Don?t eat the stuff, apply it in a well ventilated area, don?t
apply it too often and wash it off as soon as you are in-doors. That?s a
lot of precautions for something that is supposed to be safe, don?t you
think?

We?re surrounded by products that are considered safe or of very low
health risk at levels of low exposure, but the accumulative effect of each
of them over time, and all of them together is what is not taken into
perspective.

Consider some of this information from lab testing of DEET as reported by
the ?Extension Toxicology Network? and decide for yourself.

http://pmep.cce.cornell.edu/profiles/extoxnet/carbaryl-dicrotophos/deet-ext.html

?Signs and symptoms of more subtle neurotoxicity have also been associated
with extensive dermal application of Deet in adults. Questionnaire results
indicate that Everglades National Park employees having extensive Deet
exposure were more likely to have insomnia, mood disturbances and impaired
cognitive function than were lesser exposed co-workers (McConnell et al.,
1986).?

Fate in Humans and Animals

"Deet is absorbed promptly from the skin and distributed to all organs
including the brain and the fetus (in pregnant subjects). The compound is
excreted in the milk but primarily in the urine"

"Using radioautography following intravenous injection of 14C-Deet, high
tissue levels were found at first in the liver, kidney, lacrimal gland,
and nasal mucosa. Very soon, concentrations higher than that in the blood
were found in the thyroid and brown fat. Concentrations were highest and
most persistent in the lacrimal gland."

Effects on Aquatic Organisms

"One study on the acute toxicity of technical Deet to fish reported a
24-hour LC50 of 125 ppm and a 96-hour LC50 of 172 ppm for rainbow trout.
These results are sufficient to characterize Deet as slightly toxic to
coldwater fish."

I believe LC50 means it killed at least 50% of the fish, for the record.

That all doesn?t sound so cool to me. Also, consider that the use of DEET
frequently over a long distance hike will accumulate to a much more
significant level of exposure than recommended usage.

DEET alternatives can be (from some limited first-hand experience and what
I've been able to discern online) as effective as DEET, but not for the
same length of time.  If you use something other than DEET you'll have to
re-apply it much more frequently; however, it may be a product that
doesn't smell bad, won't melt your clothing, watch or water filter, and
won't be toxic to you or the waters you clean off in.

Personally, I?ll skip the military-developed toxin DEET and bring along
natural alternatives next time. Re-applying some soy oil every couple of
hours doesn?t sound so bad, though who knows, maybe it's not a good idea
to smell like a Thai stir-fry in bear country.

Just for the record, I?m just passing on some info and my perspective
here.  I aint sellin? nothin and I could be wrong!   It?s happened before.

Cheers,
Toes