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Surflan Toxicity and Cost

  • Subject: Surflan Toxicity and Cost
  • From: "Bill Meyer" njhosta@hotmail.com
  • Date: Sat, 5 Mar 2005 09:04:18 -0500

Hi Everyone,
     I sent the below message yesterday morning, but it never showed up here
so I don't know if it went through. Sorry for sending again if it did.

Hi Everyone,
     $26 for 1000-2000 sq. ft. sounds really expensive. I can't remember
exactly, but I worked out the cost of liquid Surflan last year based on the
$208 that I paid for a 2 1/2 gallon container of generic Oryzalin. It was
around $2.00 for 1000 sq. ft. at the heavier recommended rate (3 oz.). Weed
control was excellent, with virtually no weeds other than some maple tree
seedlings. As for toxicity, see the below information from Cornell
University. I would also describe Surflan as having virtually no toxicity in
the garden.
     I understand a lot of people are concerned about toxicity of chemicals
in the garden, but good reliable information is available freely on the
internet. Products in widespread use normally have many studies done on
their safety. Note the lack of any real adverse effects on dogs fed daily
doses of it. It is clearly safe for pets to get into treated areas.
      The issue of whether something is naturally produced or man-made is
irrelevant when it comes to how toxic it is. There are plenty of highly
toxic "natural" poisons from plant- and animal- produced poisons right down
to metals like lead and arsenic. I'd prefer rubbing Surflan on my skin to
rubbing poison ivy leaves, or a glass of undiluted Surflan to a bite from a
copperhead snake or a handful of tasty nightshade berries or the stings from
a few hundred bees. At the rate we use these products, we don't see anywhere
near the exposure that the people who work in the companies that produce
them do (the OSHA specs are for them), and the animal exposure tests include
much higher dosages than they would get in treated areas.
      We should treat naturally occuring and man-made chemicals the same
when we consider how dangerous they are. Some are more, some are less, but
their background has nothing to do with it. If you want to know the toxicity
of any substance, run a search on the internet and you'll usually find huge
amounts of information about it from varying sources like the EPA, OSHA,
poison control centers, and university studies. All of these people do a
great job of studying these things and informing us of the dangers (or lack
of dangers) with freely available information. If you have internet access,
you can look up poison information quickly and easily. It is well worth the
few minutes it takes.
                                  ...........Bill Meyer






           A.  ACUTE TOXICITY

               DERMAL:  The application of 2g of Surflan 75 W per kg of body
      weight to the shaved and abraded backs of rabbits for 24 hours caused
      only slight irritation which cleared rapidly. No other signs of
      toxicity were observed.  No local irritation or systemic toxicity was
      observed when 2 ml of undiluted Surflan AS per kg of body weight were
      applied to the shaved and abraded backs of rabbits for 24 hours (58).

               ORAL:  LD50 = >10,000 mg tech./kg (rat, gerbil); 1000 mg/kg
                        (cat, chicken); >1000 mg/kg (dog) (62).
                      Rats were given a single oral dose of Surflan 75W and
                        observed for 14 days.  This treatment resulted in an
                        LD50 of greater than 10 g per kg of body weight
                      No deaths occurred when rats were given a single oral
                        dose of 2 ml of undiluted Surflan AS per kg of body
                        weight (58).

               INHALATION:  Rats were exposed to 3.56 mg of Surflan 75 W, as
      a mist, per liter of air for one hour and observed for 14 days.  This
      treatment caused only minor effects which cleared within 24 hours.
      Rats were exposed to 5.7 microliters of Surflan AS (as a mist) per
      liter for one hour and observed for 14 days.  This treatment caused no
      adverse effects (58).

               EYES:  Slight irritation, which cleared within 7 days,
      when rabbits were treated in one eye with 21 mg of Surflan 75W.  In
      rabbits the instillation of 0.1 ml per eye of undiuted Surfan AS
      produced no irritation (58).


           In 2-yr feeding trials NEL for rats was 300 mg/kg diet (62).

           Chronic oral exposure of rats and mice to large doses of
      oryzalin for one year was well tolerated with no indication of
      cumulative toxicity or serious adverse effects.  Daily oral doses of
      18.75 mg of oryzalin per kg of body weight administered to dogs for
      three months were well tolerated with no toxic effects.  Oryzalin fed
      as a large component of the diet to pregnant rats during the period of
      organogenesis and early fetal development resulted in no adverse
      effects on either the dams or their progeny (58).

                        IV.  ENVIRONMENTAL  CONSIDERATIONS

            The LC50 (96 hr) for goldfish fingerlings is >1.4 mg/l (62).

            Laboratory and field studies indicate no undue hazard to fish
      from oryzalin added to water at recommended rates and above (58).

      Behavior In Or On Soils

      1.  Adsorption and leaching characteristics in several soil types:
            Oryzalin leaches to a limited extent under natural rainfall
            conditions.  Organic matter and clay content of the soil
            influence the application rate for herbicidal activity.
      2.  Microbial breakdown:  Microorganisms are believed to play a role
            in the degradation and disappearance of oryzalin from soil.  No
            specific soil organism has been identified as responsible for
      3.  Loss from photodecomposition and/or volatilization:
            Photodecomposition of oryzalin has been demonstrated in
            laboratory studies.  Volatilization from soil surfaces is
            and does not reduce the herbicidal effectiveness of oryzalin as
            soil treatment.
      4.  Resultant average persistence at recommended rates:  Field
            studies with 14C oryzalin have indicated its rapid
            biodegradability.  Oryzalin applied at the recommended rate has
            not caused injury to succeeding crops under warm, moist soil
            conditions (58).

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