Sethoxydim Risk Assessment

Table 4-4: Quantitative Risk Characterization for Aquatic Species. 
Risk Quotients 
Central 
Lower 
Upper 
Endpoint 
Fish 
Acute 
5.0e-02 
1.6e-03 
1.6e-01 
Mortality 
Chronic 
2.0e-04 
1.6e-06 
3.8e-04 
Based on acute toxicity. 
See text for discussion. 
Aquatic Invertebrates 
Acute 
2.3e-02 
7.2e-04 
7.2e-02 
Mortality 
Chronic 
9.2e-05 
7.2e-07 
1.7e-04 
Based on acute toxicity. 
See text for discussion. 
Aquatic Plants 
Acute 
2.4e-01 
7.5e-03 
7.5e-01 
EC
50 
Chronic 
9.6e-04 
7.5e-06 
1.8e-03 
Exposures (mg/L) 
Central 
Lower 
Upper 
Worksheet 
Acute 
0.060 
0.0019 
0.19 
F06 
Stream 
Longer-term 
1 
0.00024 
0.0000019 
0.00045 
F09 
Toxicity values (mg/L) 
Value (mg/L) 
Endpoint 
Section  
Fish, acute 
1.2 
Mortality 
4.3.3.2.  
Fish, chronic 
1.2 
No data found. Acute value 
4.3.3.2.  
used. 
Aquatic Invertebrates, acute 
2.6 
Mortality 
4.3.3.3 
Aquatic Invertebrates, chronic 
2.6 
No data found. Acute value 
4.3.3.3 
used. 
Aquatic plants 
0.25 
50 
4.3.3.4. 
SPECIAL NOTE: All risk characterizations are based on toxicity of formulated product, POAST.  Sethoxydim 
is much less toxic to aquatic species than is POAST. 
4-25  

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