JOINT RESEARCH CENTRE EUROPEAN COMMISSION European Chemicals Bureau Emission scenario document Emission scenario document for biocides used as for biocides used as rodenticides rodenticides Jørgen Larsen Jørgen Larsen PT 8 & PT 14 Exposure Scenario Course 9-10 October 2003, Ispra
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JOINT RESEARCH CENTRE EUROPEAN COMMISSION European Chemicals Bureau Emission scenario document for biocides used as rodenticides Jørgen Larsen PT 8 & PT.
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JOINTRESEARCHCENTRE
EUROPEAN COMMISSION
European Chemicals Bureau
Emission scenario document for Emission scenario document for biocides used as rodenticidesbiocides used as rodenticides
Jørgen LarsenJørgen Larsen
PT 8 & PT 14 Exposure Scenario Course
9-10 October 2003, Ispra
This presentationThis presentation
General issues and background Basic use and exposure scenarios of the
environment Exposure scenarios for primary poisoning Exposure scenarios for secondary poisoning Conclusions
Life-cycle of rodenticidesLife-cycle of rodenticides
Production
Formulation
Private use
Processing In product
professional use
In product Processing
Service life
Waste treatment Primary and secondary poisoning
PT 14 RodenticidesPT 14 Rodenticides
Used for controlling rodents Rats Mice Voles
Basic use scenarios Sewer systems Buildings (inside and around) Open fields Waste dumps
Realistic worst-case: 21 days campaign Day 0: 300 wax blocks Day 7: 100 wax blocks replenished Day 14: 50 wax blocks replenished
Maximum emission during 1st week: 100 blocks Weight of wax block: 0.3 kg Fraction of a.i. (substance) released: 0.9 Standard STP scenario (TGD)
200 L/day, 10,000 inhabitants
Sewer systems: STPSewer systems: STP
Variable/parameter (unit) Symbol Unit Default
Input:Amount of product used in control operation
Qprod kg 30
Fraction of active substance in product Fcproduct Dossier
Number of emission days (control operation)
Temission Days 7
Fraction of product released Freleased 0.3 + (0.6-*)
Output:Local emission of active substance to waste water during episode
Elocalwater kg.d-1
releasedproductprod
water FTemission
FcQElocal
Sewer systems: ResultsSewer systems: Results
Substance A:
Anti-coagulant (0.005% a.i.)
Elocalwater: 0.2 g a.i./day
Cinfluent: 0.1 μg a.i./L
Substance B:
Coagulant (4% a.i.)
Elocalwater: 150 g a.i./day
Cinfluent: 77 μg a.i./L
Sewer systems: ResultsSewer systems: Results
Result depends on Used amount of product (Qprod)
Fraction of a.i. in product (Fcproduct)
Fraction of release (Freleased)
Estimation of PEClocal
Fate (degradation, sorption, volatilisation) in STP (presence of STP is default for local scenario)
Dilution in aquatic environment PEClocalwater
Disposal of sludge on farmland PEClocalsoil
In and around buildingsIn and around buildings Assumptions on bait stations Assumptions on bait stations
Realistic worst-case: 21 days campaign Bait stations: 10 No. of replenishments: 5
Weight of wax block: 0.25 kg Fraction released due to spillage: 0.01 Spillage area: 0.09 m2 (0.1 m around station) Fraction ingested: 0.99 Fraction released of ingested: 0.9 Frequented area: 550 m2 (10 m around building)
Buildings: Direct emissionBuildings: Direct emission
Variable/parameter (unit) Symbol Unit Default
Input:Amount of product used in control operation for each bait box
Qprod g
Fraction of active substance in product Fcprod
Number of application sites Napp 10
Number of refilling times Nrefil 5
Fraction of product released directly to soil Frelease-D, soil 0.01
Output:
Local direct emission rate of active substance to soil from a campain
Elocal-D: 0.006 g a.i. Clocal-D: 0.04 mg a.i./kg Elocal-ID: 0.56 g a.i. Clocal-ID: 0.006 mg a.i./kg Clocal-D+ID: 0.047 mg/kg
Substance B:
Coagulant (4% a.i.)
Elocal-D: 5 g a.i. Clocal-D: 33 mg a.i./kg Elocal-ID: 446 g a.i. Clocal-ID: 4.8 mg a.i./kg Clocal-D+ID: 37 mg/kg
Open areas: AssumptionsOpen areas: Assumptionsre. pellets and impregnated grainre. pellets and impregnated grain
Pellets or impregnated grain used in rat burrow Entrance holes are sealed after application Product used: 0.1 kg Soil volume: 0.0085 m3 (lower half of 0.3 m
burrow, 0.1 m from the wall) Fraction released during application: 0.05 Fraction released during use: 0.2 Refills: 2
Open areas: Emission in rat burrowOpen areas: Emission in rat burrow
Variable/parameter (unit) Symbol Unit DefaultInput:Amount of product used in control operation Qprod g
Fraction of active substance in product Fcprod
Number of application sites Napp 1
Number of refilling times Nrefil 2
Fraction of product released to soil during application
Frelease, soil, appl 0.05
Fraction of product released to soil during use
Frelease, soil, use 0.2
Output:Local emission of active substance to soil during a campaign
C: Concentration of compound in fresh diet (mg/kg)
AV: Avoidance factor (0 to 1)
PT: Fraction of diet obtained in treated area (0 to 1)
PD: Fraction of food type in diet (0 to 1)
)//( dkgbwmgPDPTAVCBW
FIREDI
Regression equations to predict dry Regression equations to predict dry weight intake for an animal (Nagy, 1987)weight intake for an animal (Nagy, 1987)
For all birds: log DFI = 0.651 x log BW - 0.188
For songbirds: log DFI = 0.85 x log BW - 0.4
For other birds: log DFI = 0.751 x log BW - 0.521
For mammals: log DFI = 0.822 x log BW - 0.629
Daily food intake of the indicator speciesDaily food intake of the indicator species
)100/())100/(1(( AEMCFE
DEEFIR
FIR: Food intake rate of indicator species
(gram fresh weight per day)
DEE: Daily Energy Expenditure of the indicator species (kJ per day)
FE: Food Energy (kJ per dry gram)
MC: Moisture Content (%)
AE: Assimilation Efficiency (%)
From Crocker et al. 2002
Comparison of daily food intake based on Comparison of daily food intake based on different calculation methods different calculation methods
Bird Method Body Wt Mean food intake*
Song birds:Tree sparrow; Passer montanus Nagy 1987 22.0 g 6.3 gTree sparrow; Passer montanus Croker et al. 02 22.0 g 7.6 gRook; Corvus frugeligus Nagy 1987 488.0 g 87.0 gRook; Corvus frugeligus Croker et al. 02 488.0 g 67.5 g* Based on cereal seeds and fresh weight;
Comparison of daily food intake based on Comparison of daily food intake based on different calculation methods different calculation methods
Bird Method Body Wt Mean food intake*
Other birds:
Grey patridge; Perdix perdix Nagy 1987 381 g 29.5 gGrey patridge; Perdix perdix Croker et al. 02 381 g 50.6 gPheasant; Phasianua colchicus Nagy 1987 953.0 g 58.9
Pheasant; Phasianua colchicus Croker et al. 02 953.0 g 102.7* Based on cereal seeds and fresh weight;
Comparison of daily food intake based on Comparison of daily food intake based on different calculation methods different calculation methods
Animals Method Body Wt Mean food intake*
All birds: Nagy 1987 343.5 32.9 gCroker et al. 02 343.5 29.2 g
MammalsHarvest mouse, Micromys minutus Nagy 1987 7.0 1.4
Croker et al. 02 7.0 2.3* Based on cereal seeds (fresh weight)
Estimated Daily Intake of a.i. in a small Estimated Daily Intake of a.i. in a small cereal seeds eating bird (b.w. 15 g)*cereal seeds eating bird (b.w. 15 g)*
PDPTAVCBW
FIREDI
Estimated daily intake of a.i.: 19.3 mg kg bw/d
Food intake rate: 5.8 g/day
Body weight: 15 g.
Concentration of a.i. in fresh diet : 50 mg/kg
Avoidance factor: 1
Fraction of diet obtained in treated area: 1
Fraction of food type in diet: 1
* Realistic worst case; based on calculations from Crocker et al.2002
Estimated Daily Intake of a.i. in a small Estimated Daily Intake of a.i. in a small cereal seeds eating mammal (b.w. 25 g)*cereal seeds eating mammal (b.w. 25 g)*
PDPTAVCBW
FIREDI
Estimated daily intake of a.i.: 11.4 mg kg bw/d
Food intake rate: 5.7 g/day
Body weight: 25 g.
Concentration of a.i. in fresh diet : 50 mg/kg
Avoidance factor: 1
Fraction of diet obtained in treated area: 1
Fraction of food type in diet: 1
* Realistic worst case; based on calculation from Crocker et al. 2002
Uncertainty of the estimated food intakeUncertainty of the estimated food intake
Preliminary probabilistic analysis indicated that the upper 95 percentile for the estimate averaged about twice the mean estimate.This result is preliminary, but indicates the potential range of uncertainty.
If the user wished to be precautionary in their assessment, multiplying the estimated food intake by a factor of two might be a reasonable precaution against underestimating food intake.
Expected concentration of a.i. in the Expected concentration of a.i. in the animal after eliminationanimal after elimination
Variable/parameter (unit) Symbol Unit Default
Input:Estimated daily uptake of a compound ETE mg./kg/d
Fraction of daily uptake eliminated (number between 0 and 1)
El
(number between 0 and 1)Output:
Expected concentration of active substance in the animal
EC mg./kg
in the animal
)1( ElETEEC
Refinement steps in the evaluation of the Refinement steps in the evaluation of the potential for primary poisoning potential for primary poisoning
As rodenticides inevitably are toxic to non-target species an exposure assessment that is based on exclusive feeding on the bait will always come to the conclusion of potential risk. Two refinement steps are obvious:
Consider accessibility of baits: Accessibility might be reduced by requiring appropriate use
instructions to be put on the label
Consider attractivity: The bait could be unattractive to e.g. birds to a certain degree due to
colour, consistency and other factors.
Secondary poisoningSecondary poisoning
Calculation of rodenticide in target animal on Day 1 immediately after first meal
The food intake rate divided with body weight is as default set to 10% i.e. FIR/BW = 0.1
illustrating realistic worst case (AV, PT, and PD = 1) The concentration of a.i. in the bait C = 50 mg/kg
kgmgETE /5111501.0
Secondary poisoningSecondary poisoning
The estimated residue concentration in target rodent on Day 2 before meal: EC2 = 5 x (1- 0.3) = 3.5 mg/kg
Day 5 after the last meal = 13.9 mg/kg Day 6 * = 9.7 mg/kg Day 7 (mean time to death) = 6.8 mg/kg * The feeding period has been set to a default value of 5 days until the
onset of symptoms after which it eats nothing until its death
Secondary poisoningSecondary poisoning
For short term exposure the fraction of poisoned rodents in predator´s diet is assumed to be 1.
For long term exposure the fraction of poisoned rodents in predator´s diet is assumed to be 0.5.
Secondary poisoningSecondary poisoning
Predators (mammals or birds) feeding on poisoned rodents
Oral exposure (PECoral,predator) depends on ECn: Estimated Concentration in rodent on day n
ETE: Estimated daily uptake on day n Frodent: Fraction of poisoned rodent in diet of predator
ECn depends on fraction bait consumption
rodentnpredatororal FETEECPEC )(,
Secondary poisoning: Estimated Secondary poisoning: Estimated Concentration in poisoned rodentConcentration in poisoned rodent
0
2
4
6
8
10
12
14
16
18
1 3 5 7 9 11 13
Day
Res
idu
es,
mg
/kg 20% before
20% after
50% before
50% after
100% before
100% after
Refinement steps in the evaluation of the Refinement steps in the evaluation of the potential for secondary poisoning potential for secondary poisoning
If a risk is indicated the following options for refinement are promising:
Evaluate secondary poisoning studies which are already available for current rodenticides
Improve estimate of proportion of target rodent in the diet of predators; suitable information might already be available from literature on feeding ecology; otherwise data could be generated using a marker in the bait