JOINT RESEARCH CENTRE EUROPEAN COMMISSION European Chemicals Bureau Emission scenario document for biocides used as rodenticides Jørgen Larsen PT 8 & PT 14 Exposure Scenario Course 9-10 October 2003, Ispra

This 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 rodenticides Production Formulation Private use ProcessingIn product professional use In productProcessing Service life Waste treatmentPrimary and secondary poisoning

PT 14 Rodenticides PT 14 Rodenticides Used for controlling rodents Rats Mice Voles Basic use scenarios Sewer systems Buildings (inside and around) Open fields Waste dumps

Rodenticides: Application methods

Rodenticides: Compartments of concern

Sewer systems: Assumptions 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 1 st 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: STP

Sewer systems: Results Substance A: Anti-coagulant (0.005% a.i.) Elocal water : 0.2 g a.i./day Cinfluent: 0.1 μg a.i./L Substance B: Coagulant (4% a.i.) Elocal water : 150 g a.i./day Cinfluent: 77 μg a.i./L

Sewer systems: Results Result depends on Used amount of product (Q prod ) Fraction of a.i. in product (Fc product ) Fraction of release (F released ) Estimation of PEC local Fate (degradation, sorption, volatilisation) in STP (presence of STP is default for local scenario) Dilution in aquatic environment PEClocal water Disposal of sludge on farmland PEClocal soil

In and around buildings 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 m 2 (0.1 m around station) Fraction ingested: 0.99 Fraction released of ingested: 0.9 Frequented area: 550 m 2 (10 m around building)

Buildings: Direct emission

Buildings: Direct soil exposure

Buildings: Indirect emission

Buildings: Indirect soil exposure

Buildings: Results re. bait stations Substance A: Anti-coagulant (0.005% a.i.) Elocal-D: g a.i. Clocal-D: 0.04 mg a.i./kg Elocal-ID: 0.56 g a.i. Clocal-ID: mg a.i./kg Clocal-D+ID: 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: Assumptions re. 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: m 3 (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 burrow

Open areas: Concentration in rat burrow

Open areas: Results, pellets in rat burrow Substance A: Anti-coagulant (0.005% a.i.) Elocal-D: g a.i. Clocal-D: 0.17 mg a.i./kg Substance B: Coagulant (4% a.i.) Elocal-D: 2 g a.i. Clocal-D: 138 mg a.i./kg

Open areas: Assumptions re. contact powder Contact powder often used when plenty of food is available Contact powder applied directly in burrow by spoon or dust-blower Soil volume: m 3 Fraction released to soil: 0.9 Product used: 0.1 kg (example)

Open areas: Release of contact powder

Open areas: Results, contact powder Substance A: Anti-coagulant (0.005% a.i.) Elocal-D: g a.i. Clocal-D: 0.3 mg a.i./kg Substance B: Coagulant (4% a.i.) Elocal-D: 3.6 g a.i. Clocal-D: 250 mg a.i./kg

Primary poisoning: Estimated Daily Intake FIR:Food intake rate of indicator species (gram fresh weight per day) BW:Body weight (g) 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)

Regression equations to predict dry weight intake for an animal (Nagy, 1987) For all birds:log DFI = x log BW For songbirds:log DFI = 0.85 x log BW For other birds:log DFI = x log BW For mammals:log DFI = x log BW

Daily food intake of the indicator species 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 different calculation methods

Estimated Daily Intake of a.i. in a small cereal seeds eating bird (b.w. 15 g)* 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 cereal seeds eating mammal (b.w. 25 g)* 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 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 animal after elimination

Refinement steps in the evaluation of the 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 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

Secondary 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 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 poisoning Predators (mammals or birds) feeding on poisoned rodents Oral exposure (PEC oral,predator ) depends on EC n : Estimated Concentration in rodent on day n ETE: Estimated daily uptake on day n F rodent : Fraction of poisoned rodent in diet of predator EC n depends on fraction bait consumption

Secondary poisoning: Estimated Concentration in poisoned rodent

Refinement steps in the evaluation of the 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 Field studies, monitoring

Conclusions PT 14 Rodenticides Emission Scenario Document has been prepared (Danish EPA, EUBEES 2) ESD covers use scenarios and environmental compartments of (presumed) highest concern ESD based on empirical data & default values ESD has not been validated in practice ESD can be used when no other data are available Applicants should, whenever possible, use specific data on use pattern and emission rate

Conclusions PT 14 Rodenticides Emission Scenario Document has been prepared (Danish EPA, EUBEES 2) ESD covers use scenarios and environmental compartments of (presumed) highest concern ESD based on empirical data & default values ESD has not been validated in practice ESD can be used when no other data are available Applicants should, whenever possible, use specific data on use pattern and emission rate