Subject: Re: Pesticide toxicity
From: Troy Coziahr <troyc@geneseo.net>
Organization: a Digital Internet AlphaServer Site
Date: Mon, 15 Sep 1997 22:52:14 -0700
Message-ID: <MOD$970915.20105@rec.gardens.ecosystems>


In article <MOD$970910.27073@rec.gardens.ecosystems>,
moholt@gardens.com (Carol Moholt) wrote:
>
>
> Bill and Troy were talking about the various LD (lethal dose) ratings
> which measure immediate toxicity levels in test populations. While they
> are one method to use in determining whether to use a particular product
> or not, a more complete method is doing a Risk Assessment. In Risk
> Assessment, one considers four factors, only one of which refers to the
> immediate toxicity measured by the LD tests:

The reason LD50 is used so much in these discussions is that it remains the best method
for comparing "apples to apples". For some of the factors you list below, there just
isn't enough data to efficiently and fairly compare most chemicals (natural or
synthetic).

>
> In making a risk assessment to determine whether or not to use a
> pesticide, take the following factors into account:
>
> 1. Human safety. Toxicity categories measure immediate dangers to the
> person applying the pesticide and others at the site. They do not,
> however, measure long-term effects of repeated application.

Correct. But, again, this data simply doesn't exist in quantity enough to make accurate
comparisons.

> 2. Off-site movement. Pesticides may be carried beyond their initial site
> of application, through air or water, and affect other populations. For
> example, it may kill fish if finds its way into streams, rivers, lakes, or
> ponds.
ALL IMPROPERLY APPLIED PESTICIDES DRIFT - NATURAL OR OTHERWISE! 95% of drift comes from
too high pressure, spraying in too much wind, nozzles too high, speed too fast, etc.
Product formulation will make a little difference (2,4-D Amine vs. Ester for example),
but proper application will reduce drift to virtually zero.

> 3. Soil contamination. Some pesticides have little effect on the soil at
> the time of application, others may persist for long periods.
> 4. Phytoxicity. Referring to the poisoning of a plant, this assessment
> considers the tradeoff between eliminating a pest and harming a plant.
> 5. Effectiveness. Some pesticides solve a problem with one application.
> They may rank higher in toxicity or other factors than other pesticide
> choices; yet since they only are applied one time, rather than several,
> they may be the most effective choice for the situation.

All very good points. Again, I emphasize that these all apply to organic substances as
well.

>
> While most of us on this group don't use any to few pesticides,
Including me.

> I think
> it's important for us to understand as much as possible about them. For
> example, I get concerned about the widespread use of Pyrethrins, whose
> toxicity levels are so low
??? they are??? Depending on the formulation, LD50's range from 200 to 2600, right in
the same range as most all general use "chemical insecticides" Statements like this
continue to bug me. Check the label, pyrethrins (AND rotenone, etc.)are just as nasty
as a lot of the synthetics. ( Also check out their effects on bees & fish)

>that many consider them a "safe" pesticide.
> Yet, I see how consumers use this product almost as if it were water and
> are very cavalier in washing it into drains (where it can get to fish) or
> even around water sources where a lizard or snake may drink and be
> poisoned). Weighing the five risk assessment factors against a
> Pryethrin-based product-- rather than just the toxicity levels -- helps
> one realize that the use of any pesticide is complex in terms of overall
> effect.
>
> Carol Moholt

All good points, Carol. My point has always been that an ounce of prevention is worth a
pound of (pesticide) cure. But, when it comes to using pesticides, synthetics are just
as safe as most "natural" remedies. If you feel better using organic methods - great!
Go for it! I've never had any problem with that (I natural controls as well, when
practical). But I will continue to point out that those who scream about the "poison
crowd" have no evidence on their side. Scare-mongering is pointless and a waste of
energy. (stress kills too, you know)

Troy