Agriculture Reference
In-Depth Information
The LC
50
is a somewhat similar concept to the LD
50
. It is the concentra-
tion, usually in air or water surrounding test animals, that cause 50 percent
mortality. It is therefore a convenient index for studying vapors inhaled by
animal or water-soluble pesticides in contact with fish.
In this topic the average values of the oral toxicities (LD
50
values) as a
s i ng l e do se i n ges t ed b y rats o r s i mi l ar m amm al s are qu ot ed t o g i ve s o me
indication of the mammalian toxicities of different types of pesticides. The
smaller the LD
50
value, the more toxic the chemical, so that the toxicities of
chemicals can be graded by the LD
50
values as follows:
Descriptor
LD
50
(mg/kg)
Super or extremely toxic
<5
Highly toxic/hazardous
5-50
Moderately toxic/hazardous
50-500
Slightly toxic/hazardous
500-5,000
Relatively non-toxic or harmless
>5,000
Figure 5.2
Toxicity increases as signal word progresses from caution to
danger. Signal words are required on all labels and labeling.
