Synoptisches Bewertungsmodell fur Pflanzenschutzmittel

Synoptisches Bewertungsmodell fur Pflanzenschutzmittel

Introduction :

V. Gutsche and D. Rossberg developed SYNOPS_2. The purpose of this indicator is to assess the environmental risk potential of a pesticide application strategy and to compare varying pest management strategies that have different pesticide options. SYNOPS_2 considers the potential effects of pesticides on soil, air, groundwater, and surface water. The potential effects on air are considered "optional" since it has no real mass balance and no eco-toxicological impacts. The potential effects on groundwater incorporate predicted environmental concentrations from the PELMO program. PELMO is a computer program that simulates the vertical movement of pesticides in soil due to leaching. SYNOPS_2 also analyzes the potential eco-toxicological effects (acute and chronic) on soil organisms and aquatic organisms.

References:

• Ganzelmeier, H. 1997. Abtrift und Bodenbelastung beim Ausbringen von Pflanzenschutzmitteln. Mitt. Biol. Bundesanstalt Land - u. Forstwirtschaft, Berlin-Dahlem.
• Gutsche, V., Rossberg, D. 1999. Synoptisches bewertungsmodell fur pflanzenschutzmittel (SYNOPS). In J. Reus, P. Leendertse, C. Bockstaller, I. Fomsgaard, V. Gutsche, K. Lewis, C. Nilsson, L. Pussemier, M. Trevisan, H. van der Werf, F. Alfarroba, S. Blümel, J. Isart, D. McGrath, T. Seppälä (eds), Comparing Environmental Risk Indicators for Pesticides: Results of the European CAPER Project. Utrecht, The Netherlands: Centre for Agriculture and the Environment. 69-82.
• Klein, M. 1995. Pesticide Leaching Model (PELMO), User manual version 2.01. Fraunhofer- Institut für Umweltchemie und Ökotoxikogie, D57392
• Lutz, W. 1984. Berechnung von Hochwasserabflussen unter Anwendung von Gebietskenngroben. Mittlg. Inst. Hydrologie Wasserwirtschaft, Univ. Karlsruhe.
• Maniak, U. 1992. Regionalisierung von Parametern fur Hochwasserabflubganglinien. In: Regionalisierung der Hydrologie (H.B. Kleeberg), DFG, Mittlg. Senatskomm. fur Wasserf. 11, S. 325-332.
• Reus, J., Leendertse, P., Bockstaller, C., Fomsgaard, I., Gutsche, V., Lewis, K., Nilsson, C., Pussemier, L., Trevisan, M., van der Werf, H., Alfarroba, F., Blumel, S., Isart, J., McGrath, D., Seppala, T. 2002. Comparison and evaluation of eight pesticide environmental risk indicators developed in Europe and recommendations for future use. Agriculture, Ecosystems, and Environment 90, 177-187.

Reference Website:

• PELMO model
  

Equations :

Calculation of Direct Loads :

1. Drift = Dose Rate * VGT/100



2. Soil Load = (Dose Rate - Drift) * (100-VDT)/100



3. Water Load = Drift * Water Index
   

Calculation of the Concentration in Soil for each pesticide active ingredient as a function of time :

1. λ = LN 2 / DT50_soil



2. yo = Soil Load / 375 (assuming soil density of 1.5 g/cm³ and soil depth of 2.5 cm)



3. λ^*(t) = exp (0.08 * (Temp (t) - 20)) * l



4. CS_ai t_o = yo



5. CS_ai(t_i) = yo + CS_ai(t_i) * (exp -λ^*(t_i)) (for the day of the application event)
   CS_ai (t_i) = CS_ai (t_i - 1) * exp -λ^*(t_i) (for all other days following application event)



6. CS_ai (t) = ∑ CS _ai ^napp (ti)



7. sPECS_ai = max CS_ai (t)



8. IPECS_ai = ∑ CS_ai (t_i)
   

Calculation of the concentration in surface water for each a.i. as a function of time

1. yo = Water Load / 3000 (assuming water depth of 30cm)



2. Kd = Koc * %OC/100



3. f₁ = (0.02153 * Slope) + (0.001432 * Slope²) (if slope is < 20%)
   f₁ = 1 (if slope ≥ 20%)



4. f₂ = 1-Plant Interception/100



5. f₃ = 0.83 * WBZ



6. f = f₁ * f₂ *f₃



7. L%_runoff = (Q/P) * f * exp(-3*LN2/DT50_soil)*100/(1+Kd)



8. RUN_a.i. = L%_runoff * Dose Rate/3000



9. CW_ai (t_i) = CW_ai (t-1) * exp (-λ^*(t_i)) + RUN_a.i.



10. sPECW_ai = max CW_ai (t)



11. IPECW_ai = ∑ CW ai (t)

Groundwater Leaching Index :

1. LI = ⁷³⁰max_t=1 (C_sol(t, slnr₅₀)) / (C_sol(1,1)

Air Index :

1. Koc = 0.66069 Kow^1.029



2. KdS = %OC * Koc/100



3. Kdw = %OCW * Koc/100



4. AS_ai = KdS * sPECS_ai / Kds + 1



5. AW_ai = KdW * sPECW_ai / KdW + 1



6. AIR_ai = Dose Rate * minimum [DT₅₀ hydrolysis, DT₅₀ photolysis] *Kh
   

Biological Risk :

1. abr_ew = sPECS / LC50_ew



2. abr_wo = sPECW / LC50_wo



3. cbr_ew = IPECS / (NOEC_ew * t_ew)



4. cbr_wo = IPECW / (NOEC_wo * t_wo)



5. scr_ew(t) = ∑^m(∑^t(CS_ai(t)/NOEC_ew * t_ew))



6. scr_wo(t) = ∑(∑(CW_ai(t)/NOEC_wo * t_wo))



7. tscr_ew = max scr_ew



8. tscr_wo = max scr_wo
   

List of Symbols :

Symbol	Description & Units
abrew	acute biological risk for earthworms (unitless)
abrwo	acute biological risk for water organisms (unitless)
AIRai	air exposure index (g/ha/day)
ASai	adsorbent index for soil (unitless)
AWai	adsorbent index for water sediment (unitless)
cbrew	chronic biological risk for earthworms (unitless)
cbrwo	chronic biological risk for water organisms (unitless)
C_sol(1,1)	PELMO concentration of pesticide a.i. in upper soil layer (g/cm2)
C_sol(t, slnr50)	PELMO concentration of pesticide a.i. in a soil depth of 50 cm (g/cm2)
CSai	daily concentration of pesticide a.i. in soil after application event (mg/kg soil)
CSai(t)	concentration of pesticide a.i. in soil (mg/kg soil)
CSai ti	daily concentration of pesticide a.i. in soil (mg/kg soil)
CSai(ti -1)	concentration of pesticide a.i. in soil on the previous day (mg/kg soil)
CWai (t)	concentration of pesticide a.i. in surface water (mg/L)
CWai (t-1)	concentration of pesticide a.i. in surface water on the previous day (mg/L)
Dose Rate	amount of pesticide a.i. applied (g/ha)
Drift	amount of pesticide a.i. drifting to new compartments (g/ha)
DT50 hydrolysis	chemical half-life in water (days)
DT50 photolysis	chemical half-life when exposed to sun (days)
DT50soil	soil half-life (days)
f	run-off correction factor
IPECSai	long term predicted environmental concentration of pesticide a.i. in soil (mg*d/kg of soil)
IPECWai	long term predicted environmental concentration of pesticide a.i. in water (mg*d/L of water)
Kh	Henry's Law Constant (unitless)
Kd	soil adsorption coefficient (L/kg)
KdS	estimated soil adsorption coefficient (unitless)
KdW	estimated soil sediment adsorption coefficient (unitless)
Koc (for air)	estimated adsorption coefficient (unitless)
Koc (for soil)	adsorption coefficient (L/kg)
Kow	octanol-water partition coefficient
λ	degradation constant
λ*(t)	degradation constant considering the effect of temperature
LC50ew	lethal concentration 50 for earthworms (mg/kg)
LC50wo	lethal concentration 50 for water organisms (mg/L)
LI	groundwater leaching index (unitless)
L%runoff	percentage of application dose dissolved in run-off water
m	number of active ingredients in the considered strategy
napp	number of applications
NOECew	No Observed Effect Concentration for earthworms (mg/kg)
NOECwo	No Observed Effect Concentration for water organisms (mg/L)
%OC	% of organic content in soil
P	precipitation volume (mm)
Q	run-off volume (mm) from Lutz (1984) & Maniak (1997) tables
RUNai	peak amount of run-off (mg/L)
screw	subchronic risk index for earthworms (unitless)
scrwo	subchronic risk index for water organisms (unitless)
Slope	slope of field (%)
sPECSai	short term predicted environmental concentration of pesticide a.i. in soil (mg/kg soil)
sPEWai	short term predicted environmental concentration of pesticide a.i. in water (mg/L of water)
to	day of application event (Equals 0)
(t)	time increment (Equals 1 if researchers want daily pesticide a.i. concentrations)
ti	days (used only as a counting device between applications. It has no value in the equations).
Temp	temperature (oCelsius)
tscrew	maximum subchronic risk value for earthworms
tscrwo	maximum subchronic risk value for water organisms
VDT	interception % of crop
VGT	spray drift % from the Ganzelmeier spray drift table (Ganzelmeir, 1997)
Soil Load	amount of pesticide loading into the soil compartment (g/ha)
Water Load	amount of pesticide loading into the water compartment (g/ha)
Water Index	% of field bordering surface water
yo (for soil)	initial pesticide a.i. concentration in soil caused by soil loading (mg/kg soil)
yo (for water)	initial pesticide a.i. concentration in surface water caused by water loading (mg/L)

 

Analysis :

Calculations of soil and water loads of the pesticide a.i. are a function of the dose rate, a spray drift value, the percent canopy cover and a water index number which represents the relation between fields bordering any surface water body and the total field circumference in a region. This index can be set as a default value where the results are representative of the surface water conditions of the area (e.g. a region with many rivers, ditches, etc). For surface water concentrations, SYNOPS_2 has an additional component that assumes a peak run-off concentration event three days after application. SYNOPS_2 also estimates the concentration in soil and groundwater for each pesticide a.i. These calculations determine the degradation of the pesticide a.i. over time. These calculations involve the use of the pesticide's a.i. half-life in soil and water, the temperature of the area, soil density, and soil layer depth. Long-term environmental exposure is determined by summing each day's concentration of the pesticide a.i. Short-term exposure is estimated by determining the maximum concentration of the pesticide a.i. for any one day.

SYNOPS_2 calculations are quite complex. As a result, understanding the equations and the interaction of various environmental parameters may take time. Additionally, the availability of accurate data is a problem especially for certain NOEC values (e.g. NOEC earthworm values can be difficult to find). For groundwater leaching, users of this system will also have to learn the PELMO leaching simulation program. However, the PELMO leaching simulation program has a graphical user interface making it fairly easy to use. The PELMO program is also easily available from the Internet.

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