Sethoxydim Risk Assessment

Worksheet D06: Consumption of  from a stream contaminated by runoff and/or percolation, acute exposure 
scenario [DWAcStrmHHRA01]. 
Verbal Description: A young child (2-3 years old) consumes contaminated ambient water from a stream that 
has been contaminated from run-off and/or percolation  The levels in water are estimated from modeling or 
monitoring data and thus dissipation, degradation and other environmental processes are implicitly considered. 
The calculations involve multiplying the application rate (R) by the water contamination rate to get the 
concentration in ambient water.  This product is in turn multiplied by the amount of water consumed per day 
and then divided by the body weight to get the estimate of the absorbed dose. 
Parameters/Assumptions 
Value 
Units 
Source/Reference 
Application Rates (R) 
Central 
0.3 
lb/acre 
APPL.Typ 
Lower 
0.09375 
APPL.Low 
Upper 
0.375 
APPL.Hi 
Water Contamination Rate (WCR): 
Central 
0.2 
mg/L per 
AMBWAT.AWPT 
Lower 
0.02 
lb/acre 
applied 
AMBWAT.AWPL 
Upper 
0.5 
AMBWAT.AWPU 
Body weight (W) 
13.3 
kg 
PUBL.BWC 
Amount of water consumed (A) 
Central 
1 
L/day 
PUBL.WCT 
Lower 
0.61 
PUBL.WCL 
Upper 
1.5 
PUBL.WCH 
Concentration in Water (C):  R × WCR 
Central 
0.06 
mg/L 
Lower 
0.001875 
Upper 
0.1875 
Dose estimates (D): C × A ÷ W 
Central 
4.51e-03 
mg/kg bw/day 
Lower 
8.60e-05 
Upper 
2.11e-02 
WS-32  

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Worksheet D07: Consumption of contaminated water, chronic exposure scenario [DWChHHRA01]. 
Verbal Description: An adult (70 kg male) consumes contaminated ambient water for a lifetime.  The levels in 
water are estimated from modeling or monitoring data and thus dissipation, degradation and other 
environmental processes are implicitly considered.  The calculations involve multiplying the application rate by 
the water contamination rate to get the concentration in ambient water.  This product is in turn multiplied by 
the amount of water consumed per day and then divided by the body weight to get the estimate of the absorbed 
dose. 
Parameters/Assumptions 
Value 
Units 
Source/Reference 
Application Rates (R) 
Central 
0.3 
lb/acre 
APPL.Typ 
Lower 
0.09375 
APPL.Low 
Upper 
0.375 
APPL.Hi 
Water Contamination Rate (WCR): 
Central 
0.0008 
mg/L per 
AMBWAT.AWT 
Lower 
0 
lb/acre 
applied 
AMBWAT.AWL 
Upper 
0.0012 
AMBWAT.AWU 
Body weight (W) 
70 
kg 
PUBL.BWM 
Amount of water consumed (A) 
Central 
2 
L/day 
PUBL.WCAT 
Lower 
1.4 
PUBL.WCAL 
Upper 
2.4 
PUBL.WCAH 
Concentration in Water (C): R × WCR 
Central 
0.00024 
mg/L 
Lower 
0.0000019 
Upper 
0.00045 
Dose estimates (D): C × A ÷ W 
Central 
6.86e-06 
mg/kg bw/day 
Lower 
3.75e-08 
Upper 
1.54e-05 
WS-33  

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Worksheet D08a: Consumption of contaminated fish, acute exposure scenarios for recreational fisherman 
following an accidental spill [FishAcHHRA01]. 
Verbal Description: An adult angler consumes fish taken from contaminated water shortly after an accidental 
spill of a fixed amount of a field solution into a pond of a specified depth and surface area.  No dissipation or 
degradation is considered.  As in the acute drinking water scenario, the concentration in the pond estimated 
from the concentration in the spilled solution, the volume spilled and the volume of the pond, assuming 
instantaneous mixing.  The concentration in fish is estimated as the product of the concentration in water and 
the chronic BCF.  The dose is calculated as the product of the concentration in the fish and the amount of fish 
consumed divided by the body weight. 
Parameters/Assumptions 
Value 
Units 
Source/Reference 
Surface area of pond [SA] 
1000 
m
2 
N/A 
Average depth [DPTH] 
1 
m 
N/A 
Volume of pond in cubic meters [VM] 
1000 
m
3 
N/A 
Volume of pond in Liters [VL] 
1000000 
L 
1 m
3
 = 1,000 L 
Volume of spill [VS] 
200 
gallons 
N/A 
757 
liters 
1 gallon = 3.785 Liters 
Concentrations in spilled solution (C
Fld  (mg/L)
) 
Central 
3600 
mg/L 
APPL.TYPDR×1000 
Lower 
560 
APPL.LOWDR×1000 
Upper 
9000 
APPL.HI_DR×1000 
Concentrations in ambient water (C
Wat
): C
Fld
 × VS
(Liters)
 ÷ VL 
Central 
2.7252 
mg/L 
Lower 
0.42392 
Upper 
6.813 
Bioconcentration factor (BCF
(L/kg fish)
) 
1.2 
L/kg fish 
CHEM.BCFT 
Concentration in fish (C
Fish
): C
Wat
 × BCF 
Central 
3.27024 
mg/kg fish 
Lower 
0.508704 
Upper 
8.1756 
Body weight (W) 
70 
kg 
PUBL.BWM 
Amount of fish consumed (A) 
Central 
0.158 
kg/day 
PUBL.FAU 
Lower 
0.158 
PUBL.FAU 
Upper 
0.158 
PUBL.FAU 
Dose estimates (D): C
Fish
 × A ÷ W 
Central 
7.38e-03 
mg/kg bw 
Lower 
1.15e-03 
Upper 
1.85e-02 
WS-34  

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