Sethoxydim Risk Assessment

Appendix 1: Toxicity of Sethoxydim (NP-55) and Poast to experimental mammals [94-99% a.i. unless 
otherwise specified]. 
Animal 
Dose/Exposure 
Response 
Reference 
OCULAR 
Rabbits, Japanese, 
white, 9 males, 3-4 
months old, avg 
bw 3.3 kg 
0.1 mL NP-55 20% EC 
applied to everted 
lower lid of the right 
eye; left eye served as 
control; treated eyes of 
6 rabbits remained 
unwashed; remaining 3 
treated eyes were 
flushed with lukewarm 
Injuries were observed on the cornea and the 
conjunctivae of rabbits, with more severe injury 
in the unwashed group than in the washed 
group. 
Mean total primary irritation scores were: 
Washed group (n=3): 6.0, 6.0, 1.3, 0.7, and 0 
on respective days, 1, 2, 3, 4, and 7, ). 
Souma et al. 
1981 
MRID 
00100529 
water no sooner than 
20-30 minutes after 
instillation.  7-day 
observation period. 
Unwashed group (n=6): 32.0, 31.0, 28.0, 17.0, 
and 7.7 on respective days, 1, 2, 3, 4, and 7). 
Appendix 1 - 10 

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Appendix 1: Toxicity of Sethoxydim (NP-55) and Poast to experimental mammals [94-99% a.i. unless 
otherwise specified]. 
Animal 
Dose/Exposure 
Response 
Reference 
OCULAR - continued 
Rabbit, White 
Vienna, 3 males 
(avg wgt 2.45 kg) 
and 3 females (avg 
wgt 2.80 kg) 
INHALATION-acute 
Rats, Wistar, 
males (mean bw = 
260±12.0 g), 
females (mean bw 
= 187±7.2g), 8-9 
weeks old, 
5/sex/group 
Rats, 
Sprague-Dawley, 
males and females, 
bw range 185±15 
g, 10/sex/dose 
group 
0.1 mL unchanged 
BAS 9052OH into 
conjunctival sac of 
right eye; untreated eye 
served as control; 
observation period of 
15 days. 
single head-nose 
exposure to 1.3 or 5.6 
mg/L sethoxydim 
liquid aerosol for 4 
hours; 14-day 
observation period. 
single head-nose 
exposure to 7.64 mg/L 
Poast
 liquid aerosol for 
4 hours; 14-day 
observation period. 
INHALATION-subchronic 
Rats, Wistar, 
males (mean bw 
253 g) and females 
(mean bw 184 g), 
about 7 weeks old, 
5/sex/dose group 
head-nose exposure to 
0, 0.04, 0.3, or 2.4 
mg/L for 6 
hours/working for 1 
month (21 exposures) 
Primary irritation index equals 35; all effects 
Kirsch and 
reversible in 15 days. 
Hildebrand 
(1983) 
MRID 
00130673 
LC
50
 > 5.6 mg/L 
Gamer 1991 
MRID 
No pathological findings at sacrifice 
44021201 
LC
50
 > 7.64 mg/L 
BASF 1980 
EPA/OTS 
Neurotoxicity manifested as considerably 
88-9200030 
staggering gait and crouching posture persisted 
87 
for 6 days post dosing. 
NOEC = 0.04 mg/L 
Gamer 1993 
MRID 
NOAEC = 0.3 mg/L 
44021202 
At 0.3 mg/L, slight local irritation of the nose 
was observed but not considered an adverse 
effect. 
At 2.4 mg/L, slight irritation to the upper 
respiratory tract and oral cavity; slight systemic 
toxicity to the liver demonstrated by increased 
blood bilirubin and organ weights as well as 
centrilobular cloudy swelling of the 
hepatocytes. 
Appendix 1 - 11 

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Appendix 1: Toxicity of Sethoxydim (NP-55) and Poast to experimental mammals [94-99% a.i. unless 
otherwise specified]. 
Animal 
Dose/Exposure 
Response 
Reference 
INTRAVENOUS-acute 
Rats, Fischer 344, 
6 weeks old, males 
(avg bw 120.0 g) 
and females (avg 
bw 25.8 g), 
10/sex/dose group 
Mice, ICR, 6 
weeks old, males 
(avg bw 32.9 g) 
and females (avg 
bw 25.8 g), 
10/sex/dose group 
single dose of 0, 415, 
455, 500, 550, or 605 
mg/kg NP-55 by iv 
injection into caudal 
vein; 14-day 
observation period 
NP-55 suspended in 
0.5% CMC in distilled 
water w/0.2% Tween 
80 
single dose of 0, 348, 
417, 500, 600, or 720 
mg/kg NP-55 by iv 
injection into caudal 
vein; 14-day 
observation period 
NP-55 suspended in 
0.5% CMC in distilled 
water w/0.2% Tween 
80 
LD
50
 = 505 mg/kg (95% cl 472-540) males 
LD
50
 = 505 mg/kg (95% cl 481-530) females 
Mortality observed at >455 mg/kg, and all mice 
died at 605 mg/kg. 
General signs of toxicity included ataxia, lack 
of reflex, tremor, convulsion, labored 
respiration (gasping), stretching of hind limb, 
and lacrimation. 
In survivors, ataxia, lack of reflex, convulsion, 
and gasping recovery occurred after 20 
minutes; recovery of spontaneous movement 
occurred thereafter, and slight piloerection and 
urinary incontinence only appeared after 24 
hours. 
Autopsy in lethal cases showed common 
occurrence of remarkable hyperemia of lungs, 
much serum in the thoracic cavity which flowed 
through nasal cavity in heavy behavior rats, and 
slight fading discoloration of the kidneys. 
In survivors, only pathological change was 
inflammation site of the lungs. 
LD
50
 = 485 mg/kg (95% cl 441-534) males 
LD
50
 = 505 mg/kg (95% cl 435-586) females 
Mortality observed at >417 mg/kg, and all mice 
died at 720 mg/kg. 
General signs of toxicity included dose related 
ataxia, loss of spontaneous movement, and 
depression.  Effects were transient in survivors. 
Neurotoxic effects included ataxia, convulsions, 
and hyporeflexia. 
Bio-Medical 
Research 
Laboratories 
Co, Ltd. 
1980 
EPA/OTS 
88-9200030 
22 
Bio-Medical 
Research 
Laboratories 
Co, Ltd. 
1979 
EPA/OTS 
88-9200029 
76 
Appendix 1 - 12 

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