Sethoxydim Risk Assessment
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- Bu səhifədəki naviqasiya:
- Worksheet F13a
- Drift
- Worksheet F13a (continued)
- Worksheet F13b
Worksheet F13a: Consumption of contaminated vegetation by a large bird, chronic on-site exposure scenario. [VegChLBrd01] Verbal Description: A 4 kg herbivorous bird, such as a Canada Goose, consumes grass for a 90 day period after application of the chemical. The contaminated vegetation accounts for 10 to 100% of the diet assuming that the animal spends 10% to 100% of the time feeding at the site. Because the location is the application site, drift is set to unity - i.e., direct spray. Residue estimates based on short grass. Caloric requirements are used to estimate food consumption from U.S. EPA/ORD (1993). Dissipation is considered using the foliar halftime and taking the geometric mean of the initial and day-90 residues as the measure of dose. Parameters/Assumptions Value Units Source/Reference Body weight (W) 4 kg N/A Caloric requirement (KR) 467.5185 kcal/day U.S. EPA/ORD (1993, p. 3-6) above based on following equation: kcal/day = 3.12 × W(g) 0.604 Caloric content of vegetation (dry weight, KCD) 2.46 kcal/g U.S. EPA/ORD (1993, p. 3-5) Water content of vegetation (proportion, PW) 0.85 unitless U.S. EPA/ORD (1993, p. 4-14) Caloric content of vegetation (wet weight, KCW) 0.369 kcal/g KCD × (1-PW) Food consumed per day (wet weight, A) 1.266988 kg (KR ÷ KCW)/1000 g/kg Duration of exposure (T) 90 days N/A Application rates (R) Central 0.3 lb/acre APPL.Typ Lower 0.09375 APPL.Low Upper 0.375 APPL.Hi Residue rates (rr) Central 85 mg/kg veg per HG.SGT Lower 85 lb/acre HG.SGT Upper 240 HG.SGU Drift (Drift): Central 1 unitless Set to unity for on-site Lower 1 assessment. Upper 1 Day 0 Conc. in Vegetation (C 0 ): R × rr × Drift Central 25.5 mg/kg Lower 7.96875 Upper 90 Foliar dissipation coefficient (k) Central 0.2310491 day -1 Worksheet B02 Lower 0.2310491 Upper 0.2310491 Conc. in Vegetation at time T (C T ) [C 0 × e -k ×T ] Central 2.37e-08 mg/kg Lower 7.42e-09 Upper 8.38e-08 WS-61 Worksheet F13a (continued): Consumption of contaminated vegetation by a large bird, chronic on-site exposure scenario. Time-weighted Average Concentration on Vegetation (C TWA ): C 0 (1 - e -k T ) ÷ (k T) Central 1.226291 mg/kg Lower 0.383216 Upper 4.328085 Proportion of diet contaminated (P D ) Central 0.3 unitless See section 4.2.2.3. Lower 0.1 Upper 1.0 Dose estimates (D): P D × C TWA × A ÷W Central 1.17e-01 mg/kg bw Lower 1.21e-02 Upper 1.37e+00 WS-62 Worksheet F13b: Consumption of contaminated vegetation by a large bird, chronic off-site exposure scenario. [VegChLBrd02] Verbal Description: A 4 kg herbivorous bird, such as a Canada Goose, consumes grass for a 90 day period after application of the chemical. The contaminated vegetation accounts for 100% of the diet assuming that the animal spends all of the feeding time near the site. Drift is estimated at 25 to 100 feet from the application site. Residue estimates are based on short grass. Caloric requirements are used to estimate food consumption. Dissipation is considered using the foliar halftime and taking the geometric mean of the initial and day-90 residues as the measure of dose. Parameters/Assumptions Value Units Source/Reference Body weight (W) 4 kg N/A Caloric requirement (KR) 467.5185 kcal/day U.S. EPA/ORD (1993, p. 3-6) above based on following equation: kcal/day = 3.12 × W(g) 0.604 Caloric content of vegetation (dry weight, KCD) 2.46 kcal/g U.S. EPA/ORD (1993, p. 3-5) Water content of vegetation (proportion, PW) 0.85 unitless U.S. EPA/ORD (1993, p. 4-14) Caloric content of vegetation (wet weight, KCW) 0.369 kcal/g KCD × (1-PW) Food consumed per day (wet weight, A) 1.266988 kg (KR ÷ KCW)/1000 g/kg Duration of exposure (T) 90 days N/A Application rates (R) Central 0.3 lb/acre APPL.Typ Lower 0.09375 APPL.Low Upper 0.375 APPL.Hi Residue rates (rr) Central 85 mg/kg veg per HG.SGT Lower 85 lb/acre HG.SGT Upper 240 HG.SGU Drift (Drift): 50 feet 0.0101 unitless Estimated from 100 feet 0.0058 AgDRIFT for low-boom applications. See 25 feet 0.0187 Worksheet A06. Day 0 Conc. in Vegetation (C 0 ): R × rr × Drift Central 0.25755 mg/kg Note: lower value based Lower 0.04622 on typical rr and lower R. Upper 1.683 Foliar dissipation coefficient (k) Central 0.2310491 day -1 Worksheet B02 Lower 0.2310491 Upper 0.2310491 Conc. in Vegetation at time T (C T ): C 0 × e -k ×T ] Central 2.40e-10 mg/kg Lower 4.30e-11 WS-63 Yüklə 4,8 Kb. Dostları ilə paylaş:
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