Chronic dietary toxicity/oncogenicity studies on 2,4-dichlorophenoxyacetic acid in rodents.
Forms of 2,4-dichlorophenoxyacetic acid (collectively known as 2,4-D) are herbicides used to control a wide variety of broadleaf and woody plants. Doses in the 2-year chronic/oncogenicity rat study were 0, 5, 75, and 150 mg/kg/day. The chronic toxicity paralleled subchronic findings, and a NOEL of 5 mg/kg/day was established. A slight increase in astrocytomas observed (in males only) at 45 mg/kg/day in a previously conducted chronic rat study was not confirmed in the present study at the high dose of 150 mg/kg/ day. Doses in the 2-year mouse oncogenicity studies were 0, 5, 150, and 300 mg/kg/day for females and 0, 5, 62.5, and 125 mg/ kg/day for males. No oncogenic effect was noted in the study. In summary, the findings of these studies indicate low chronic toxicity of 2,4-D and the lack of oncogenic response to 2,4-D following chronic dietary exposure of 2,4-D in the rat and mouse.
Charles
J M
JM
Charles, Conn, & van Gemert, LLC, Durham, North Carolina 27705, USA.
Bond
D M
DM
Jeffries
T K
TK
Yano
B L
BL
Stott
W T
WT
Johnson
K A
KA
Cunny
H C
HC
Wilson
R D
RD
Bus
J S
JS
D015084:2,4-Dichlorophenoxyacetic Acid / Q000633:toxicity*; D000818:Animals; D015197:Carcinogenicity Tests; D004032:Diet; D005260:Female; D006540:Herbicides / Q000633:toxicity*; D008297:Male; D051379:Mice; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D011916:Rats, Inbred F344; D013045:Species Specificity
D006540:Herbicides; D015084:2,4-Dichlorophenoxyacetic Acid