Subject: Re: Roundup
From: Troy Coziahr <troyc@geneseo.net>
Organization: a Digital Internet AlphaServer Site
Date: Wed, 03 Sep 1997 21:45:24 -0700
Message-ID: <MOD$970903.19255@rec.gardens.ecosystems>


> >
> > BTW Does anyone know what means "the 96-hour LC50 was 8.3 mg/l with
> > Roundup and 38 ppm with glyphosate" or " The acute oral LD50 in the
> > rat is 5,600 mg/kg." ? Presumably LC50 is some sort of statistical
> > measure.
>
> LD = "lethal dose"
> LC = "lethal concentration"
>
> The 50 means 50% -- as in that particular dose caused 50% of the test
> animals to die.
>
> LC50 is usually expressed in parts per million (ppm), and oral LD50 is
> expressed in milligrams of the substance per kilogram of the test animals
> body weight.
>
> Example - Oral LD50 = 3,000
>
> 10 lab rats each weighing one pound. On average, 3,000 mg of that
> substance given to each rat would kill 5 of the rats.
>
> Troy

Ooops! That should have read "10 rats each weighing one KILOGRAM"

Sorry for the goof-up!

I also should have pointed out that LC50 usually refers to inhalation
hazard (concentration in the air), and oral LD50 refers to ingestion
hazard.

Troy