INSTITUTO NACIONAL DE INVESTIGACIÓN
Y TECNOLOGÍA AGRARIA Y
ALIMENTARIA (INIA)
MINISTERIO
DE CIENCIA
E INNOVACIÓN
SUBDIRECCIÓN GENERAL DE
INVESTIGACIÓN Y TECNOLOGÍA
DEPARTAMENTO DE MEDIO AMBIENTE
ANNEX TO THE CHLOROPHACINONE ENVIRONMENTAL RISK ASSESSMENT REPORT
Assessing the environmental risk for primary and secondary poisoning
in birds and mammals of the rodenticide chlorophacinone
Prepared for the Spanish Ministry of the Environment and Rural and Marine Affairs, by
Suárez E., Fernández C., Pro J., Ramos C., Unamuno V., Ortiz J., Haro A., and Tarazona, J.V.
Division of Ecotoxicology and Environmental Risk Assessment. Department of the Environment, INIA.
as an annex to the chlorophacinone CAR
September, 2008
INTRODUCTION
The European legislation and in particular Directive 98/8/EC requires a comprehensive assessment
of the potential risks for health and the environment of biocidal products. The risk assessment
process basically follows the general principles developed for chemicals in general, although
specific exposure scenarios are obviously required for several product types. As a consequence, the
Technical Guidance Document, initially developed for industrial chemicals, was updated in 2003
and recommended for the assessment of biocidal products (ECB, 2003). At that moment, it was
considered that the main differences in the assessment of these products were related to the
exposure pattern, and no specific adaptations of the effect part assessment were deemed necessary.
The experience gained through the implementation of the European legislation indicates that
although the basic principles are similar and, therefore, the guideline is still useful as a general
reference, the environmental effect assessment of some biocidal product types requires further
considerations, which may significantly deviate from the guidelines which are applied to industrial
chemicals with no biological activity.
Basically, the main difference is the possibility for an initial identification of the ecological
receptors which are expected to be more relevant in the overall assessment. This possibility allows a
better development of the testing strategy and risk refinement, allocating properly the resources and
moving directly to a higher tier risk assessment whenever the need for an in-depth assessment can
be anticipated.
Rodenticides represent one of the best examples for this approach. It is clear that despite other
potential needs, the aspects associated to the primary and secondary poisoning assessment would
constitute for all products a major element of the environmental risk assessment.
ANNEX: Assessing the environmental risk for primary and secondary poisoning in birds and mammals of the rodenticide chlorophacinone
Rodents, may represent a problem to be solved in some anthropogenic environments, but obviously
also represent a key element for a proper functioning of ecosystems. With the current level of
knowledge, it should be assumed that the likelihood of getting a chemical with low toxicity for wild
rodents and high efficiency for rodents as a pest, being in both cases the same or closely related
species, is very low if any. As a consequence risk reduction, and particularly exposure reduction,
measures become essential for establishing the acceptability of each specific product.
In a simplistic world the need of risk mitigation effects could be interpreted in the sense that refined
higher tier assessment are no longer required. The reality is, however, very different, and under
scientific grounds the only way for confirming the effectiveness of the mitigation measures is a
higher tier assessment reflecting the magnitude and likelihood of the remaining expected
environmental consequences.
The efficacy of a rodenticide is not just based on its acute toxicity, the mechanisms exerting this
toxicity are essential for getting a proper efficacy, limiting reductions related to resilient effects
(e.g. development of resistance) and learning behaviour. Obviously, these mechanisms are also
relevant when addressing the environmental risk of these chemicals, in particular, those associated
to primary and secondary oral poisoning of mammals and other terrestrial vertebrates.
This report, discusses the specificities of the environmental risk assessment of rodenticides using
chlorophacinone as a model chemical, offering a protocol for a higher tier refined assessment based
on the information available on their efficacy and mechanism of action. The report offers relevant
information for the environmental risk assessment of chlorophacinone, covering not only the
generic assessments conducted under Directive 98/8/EC, but also for site-specific risk assessments,
comparative risk assessment, cost/benefit evaluations for rodenticide uses in emergence situations,
or risk-based identification techniques employed as environmental monitoring and diagnosis tools.
ADAPTATION OF THE CONCEPTUAL MODEL
A proper conceptual model, linking the different aspects of the risk assessment is an essential
element for developing a risk protocol (US EPA; 1998; SSC, 2003). Basically, the model must
describe the connections between the problem formulation, the analysis phase (including exposure
and effects), the risk characterization, and whenever relevant, the risk perception and
communication strategy. A graphic representation of the conceptual model is considered a standard
practice in US ecological risk assessments, but it is not so common in European regulatory
protocols, where guidance, such as the TGD, tend to offer graphic representations for the exposure
part but not for the overall conceptual model.
For rodenticides, the model should include both primary and secondary poisoning assessments.
Primary poisoning covers the risk associated to the direct consumption of the rodenticide baits by
non-target organisms. Secondary poisoning is associated to the indirect exposure related to the
accumulation of the rodenticide in organisms which are in fact food items for other organisms
occupying higher levels in the trophic chain. The secondary poisoning assessment includes in
reality three complementary processes: the ingestion of the target “pest” organisms, whose
relevance depends on the toxicokinetics and toxicodynamics of the chemical, the exposure through
bioconcenration/bioaccumulation processes, and the biomagnification through the food-chain.
It should be noticed that the TGD only covers the two last processes, as primary poisoning and the
consumption of exposed target organisms are of no relevance for the assessment of industrial
chemicals, which was the main aim to be covered during the elaboration of the TGD.
INIA Report. Department of the Environment, Division of Ecotoxicology and Environmental Risk Assessment
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ANNEX: Assessing the environmental risk for primary and secondary poisoning in birds and mammals of the rodenticide chlorophacinone
PRIMARY AND SECONDARY POISONING ASSESSMENT
The aim of a rodenticide is to be consumed by a mammal and to provoke a toxicity process
resulting directly or indirectly in a lethality event. The efficacy of the treatment requires affecting a
sufficient number/percentage of the pest population, as the reproductive strategy of a rodent pest
population requires a sufficient level of control avoiding a rapid recovery of the population.
This fact linked to the abovementioned need of a high degree of efficacy in order to avoid
resistances to the rodenticides leads to a short-term exposure situation. Quoting the EUBEES 2
guideline in relation to the primary and secondary poisoning: “It could be argued that both an acute
and a chronic risk assessment should be done for anticoagulants, because although the mode of
action is generally chronic, some anticoagulants have substantial acute toxicity”.
It should be considered that the term chronic in the EUBEES-2 guideline refers in reality to a
repeated exposure within a much shorter period, normally few days with daily exposure, than the
standard chronic toxicity assessment based on the whole or a significant part of the lifetime of the
species.
Primary poisoning assessment
For the conceptual model, the primary poisoning considers two complementary scenarios:


Sporadic exposures of non-target animals to the bait
a. Estimating the likelihood for lethality event associated to the consumption of the
amount of rodenticide employed in a single bait, i.e.,
i. The number of baits that should be consumed for resulting in a lethality event
Repeated exposures of non-target animals to the bait
a. Estimating the likelihood for chronic effects associated to the repeated consumption
of the rodenticide, i.e.,
i. Temporal/spatial estimations for the likelihood of cumulative/repeated
exposures resulting in chronic effects.
It should be noticed that the definition of non-target individual is not necessarily associated to the
species. Individuals from the same species may be considered target when present in certain areas
(buildings, farm facilities, etc.), and non-target when present outside these anthropogenic areas.
Secondary poisoning assessment
The secondary poisoning assessment focuses on predatory birds and mammals feeding on other
vertebrates. Unlike other biocides, the accumulation of rodenticides in plants is not considered of
particular relevance, and therefore no specific scenario has been developed.
As already mentioned, this evaluation includes in reality three complementary processes, one
specific for rodenticides:

the ingestion of the target “pest” organisms:
o Likelihood for acute and/or chronic effects in vertebrates feeding on the pests and
the pest carcasses, i.e.,
 Percentage of pest animals/carcasses in the diet for provoking lethal and
sublethal events.
INIA Report. Department of the Environment, Division of Ecotoxicology and Environmental Risk Assessment
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ANNEX: Assessing the environmental risk for primary and secondary poisoning in birds and mammals of the rodenticide chlorophacinone
And two processes related to generic environmental fate processes, independent of the intended
uses, and whose relevance depends on the intrinsic properties of the molecule:

the exposure through bioconcentration/bioaccumulation processes
o Likelihood for effects due to bioconcentration in fish and/or soil-dwelling organisms,
which can be consumed by birds and mammals, i.e.,
 Comparison of the estimated concentration in biota with the toxicity results.

the biomagnification through the food-chain
o Additional concern for top predators associated to repeated bioaccumulation
processes within the same food web, i.e.,
 Likelihood for long-term continuous exposure in top predators and estimated
margins of exposure.
SUMMARY OF TOXICITY DATA ON BIRDS AND MAMMALS
The effect assessment for oral exposures can be presented in different formats, from concentration
in the food to critical body burdens.
Briefly, the following methods can be found in different risk assessment guidelines:
 Concentration in food, if food consumption data are not provided, the uncertainty is very
high.
 External dose: amount of administered chemical corrected by the body weight. It is the
standard approach when using mammalian data and the OECD recommendation for bird
data.
 Internal dose: internal concentration of the chemical in the organisms and/or target tissue. It
offers additional information and reduces part of the toxicokinetic uncertainty.
 Critical body burden: It offers a mechanistic interpretation of the internal dose approach
referred to the target organ. It is based on the identification of the target organ/tissue, the
knowledge on the mode of action of the chemical, and combinated information from
different studies, exposure conditions, species, etc. for setting an effect threshold for target
organ concentrations. It must be noticed that this approach cannot be applied to all
chemicals. It is only suitable for chemicals with a mode of action in which the effects are
directly associated to reaching a concentration in a target organ, independently of the time
and conditions required for reaching that level.
The TGD recommends the use of internal dose, but assuming that this information is not normally
available, presenting a method based on concentrations in food. Most risk assessment guidelines
prefer the use of the external dose method, which reduces the uncertainty associated to lab to field
differences in food intake ratios.
Effect assessment for birds
Table 1 summarises the available toxicity data of chlorophacinone for birds.
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ANNEX: Assessing the environmental risk for primary and secondary poisoning in birds and mammals of the rodenticide chlorophacinone
Table 1. Toxicity of chlorophacinone to birds**
Guideline
/
Species
Endpoint /
Test method
Type of test /
Duration
SETAC (1995)
Bobwhite quail
LD50 /acute orala
(Colinus virginianus)
SETAC (1995)
Bobwhite quail
LD50/ acute oral
(Colinus virginianus)
OECD 205*
Bobwhite quail
LC50/ short-term
(Colinus virginianus)
dietary/ 5 days
OECD 205
OECD 206
Mallard duck
(Anas platyrhynchos)
Japanese quail
(Coturnix coturnix
japonica)
LC50/ short-term
dietary/ 5 days
NOEC
(reproduction 90
days)
Results
NOEC
L(D)C50
159 mg a.s/kg
bw
< 100 mg a.s/kg
bw
10 mg a.s/kg
food
495 mg a.s/kg
bw
257 mg a.s·kg
bw-1·d-1
95 mg a.s/kg
food
< 10 mg a.s/kg
food
1 mg a.s/kg food
(mortality)
4 mg a.s/kg food
(egg production)
Equivalent to
17.3 mg
a.s·kgbw-1·d-1
204 mg a.s/kg
food
Reference
Reliability
Doc. A-III
7.5.3.1.1-01
Doc. A-III
7.5.3.1.1-02
Doc. III-A
7.5.3.1.2-01
3
Doc. III-A
7.5.3.1.2-02
Doc. III-A
7.5.3.1.3-01
2
1
2
3
a
Diet included a source of vitamin K.
*key study in bold.
** Data from the risk assessment report for chlorophacinone. July 2008.
Based on these data, the following Estimated No Effects Levels (ENEL) are derived:
ENEL single dose: 6.42 mg a.s·kg bw-1·d-1
Based on the toxicity endpoint 257 mg a.s·kgbw-1·d-1, with an assessment factor (AF) of 40.
This AF is obtained from the combination of a factor of 4, based on the slope of the acute
toxicity curve, for estimating the LD0 from the LD50 endpoint, and a factor of 10 to cover the
interspecies extrapolation.
An analysis with all the LD50 and LD0 for the same endpoint, mortality was carried out. The
species analysed where for fish: O. mykiss, L. macrochirus; aquatic invertebrates: D. magna;
terrestrial invertebrates: E. foetida; birds: C. virginianus; and mammals: Rattus norvegicus and
Beatle dog, and the ratios varied from > 1.3 for STP microorganims (activated sludge) to the
highest for mammals (Rattus norvegicus) with a value above 3. In order to cover all the
organisms an AF of 4 was adopted.
ENEL short-term: 0.43 mg as·kg bw-1·day-1
Based on the toxicity endpoint 17.3 mg a.s·kgbw-1·d-1, with an assessment factor (AF) of 40.
This AF is obtained from the combination of a factor of 4, based on the slope of the acute
toxicity curve, for estimating the LD0 from the LD50 endpoint, and a factor of 10 for
covering the interspecies extrapolation
ENEL long-term: 0.017 mg a.s·kgbw-1·d-1
The reproduction study has a low reliability and therefore is not suitable for a ENEL
derivation. This value is estimated from the short-term toxicity endpoint 17.3 mg a.s·kgbw1 -1
·d , using an assessment factor of 1,000 for covering acute to chronic and interspecies
variability. This factor is equivalent to the TGD recommendation of an AF of 3,000 for
toxicity expressed in terms of a dietary exposure (concentration in food), as the additional
factor of 3 is included for covering the uncertainty associated to lab to field differences in
food intake ratios.
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ANNEX: Assessing the environmental risk for primary and secondary poisoning in birds and mammals of the rodenticide chlorophacinone
Semifield NOAEL > 0.73 mg a.s·kgbw-1 in five days = 0.15 mg a.s·kg bw-1·d-1
Based on a study with birds fed on carcasses of chlorophacinone-dead rats.
Effect assessment for Mammals
Table 2 summarises the available toxicity data of chlorophacinone for mammals.
Table 2. Toxicity of chlorophacinone to mammals**
Species
Endpoint
Value
(mg a.s·kgbw-1)
(mortality)
Rattus
Acute oral toxicity
LD50 males
3.15 (1.48-6.68)
norvegicus
LD50 females
10.95 (6.46-18.57)
LD50 males&females
6.26 (3.96-9.89)
Beagle dog
Acute oral toxicity
LD50
«2
Rattus
Subchronic oral toxicity NO(A)EL
0.005
11 to 16 weeks
norvegicus*
LO(A)EL
0.010
LD50 (estimation)
0.05***
Rattus
Teratogenicity
study. NO(A)EL
0.050
norvegicus
Developmental
toxicity LO(A)EL
0.100
study in rats
10+5 days
New Zealand Teratogenicity
study. NO(A)EL
0.010
white rabbit
Developmental
toxicity LO(A)EL
0.025
study in rabbits
13+11 days
* key study in bold.
** Data from the risk assessment report for chlorophacinone. July 2008.
*** Estimation of LD50 for short-term effects from the raw data in this study.
Reference
Reliability
III-A 6.1.1-01
1
III-A 6.1.1-02
III-A 6.4.1-01
3
2
III-A 6.8.1-01
1
III-A 6.8.1-02
1
Based on these data, the following Estimated No Effects Levels (ENEL) are derived:
ENEL single dose: « 0.05 mg a.s·kgbw-1·d-1
Based on the toxicity endpoint « 2 mg as·kg bw-1·d-1, with an assessment factor (AF) of 40.
This AF is obtained from the combination of a factor of 4, based on the slope of the acute
toxicity curve, for estimating the LD0 from the LD50 endpoint, and a factor of 10 for
covering the interspecies extrapolation.
ENEL short-term: 0.00125 mg a.s·kgbw-1·d-1
Based on the toxicity endpoint 0.05 mg a.s.kg bw-1·d-1, with an assessment factor (AF) of
40. This AF is obtained from the combination of a factor of 4, based on the slope of the
acute toxicity curve, for estimating the LD0 from the LD50 endpoint, and a factor of 10 for
covering the interspecies extrapolation.
ENEL long-term: 0.00017 mg a.s·kg bw-1·d-1
The reproduction study has a low reliability and therefore it is not suitable for a ENEL
derivation. This value is estimated from the subchronic oral toxicity endpoint NOEL =
0.005 mg a.s·kgbw-1·d-1, using an assessment factor of 30 for covering subchronic to chronic
and interspecies variability. This factor is equivalent to the TGD recommendation of an AF
of 90 for toxicity expressed in terms of a dietary exposure (concentration in food), as the
additional factor of 3 is included for covering the uncertainty associated to lab to field
differences in food intake ratios.
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ANNEX: Assessing the environmental risk for primary and secondary poisoning in birds and mammals of the rodenticide chlorophacinone
ENEL mortality repeated exposure: 0.010 mg a.s·kg bw-1·d-1
Based on the long-term mortality LOEL of 0.010 mg a.s·kg bw-1·d-1. It must be mentioned
that the NOEL mortality was equal to the study NOEL; confirming mortality as the relevant
endpoint for chlorophacinone even for long-term repeated exposures.
Short-term mortality LD50 between 0.04-0.08 mg a.s·kg bw-1·d-1
Semifield LD50: about 0.064 mg a.s·kg bw-1·d-1
Based on a 55% mortality at 0.32 mg a.s·kgbw-1 distributed in five days
Semifield critical body burden 0.542 mg a.s·kgbw liver-1
RISK CHARACTERISATION FOR PRIMARY AND SECONDARY POISONING
Non-target vertebrates may be exposed to chlorophacinone either directly by ingestion of exposed
bait blocks (primary poisoning) or indirectly by ingestion of the carcasses of target rodents that
contain chlorophacinone residues (secondary poisoning). A set of exposure scenarios based on
EUBEES2 exposure proposals and the approaches for effect assessment presented above are
included here.
In and around buildings
Exposure assessments have also been conducted for other baiting scenarios based on standard use
patterns for sewers, open areas and waste dumps. The range and extent of exposure in these
scenarios did not exceed that predicted to arise from use in and around buildings. The following
discussions therefore focus on the In and around buildings scenario, since this represents the worst
case.
Primary poisoning
Basically the same set of physiological processes is responsible for maintaining life for warm-blood
animals, i.e. mammals and birds. Therefore, since the use of rodenticides is meant for killing
selected pest mammals, it has to be considered a general hazard to non-target mammals, and birds
as well.
Tier 1, primary poisoning
To estimate the exposure to non-target vertebrates, it is assumed in the first instance that a quantity
of bait block will be eaten on a single occasion to satisfy a whole day’s food intake requirement. As
a tier 1, the actual assessment is normally based on a comparison of the (predicted) concentration of
the chemical in the food (PECoral) and the (predicted) no-effect concentration for oral intake for the
non-target organisms (PNECoral). The external dose approach, which reduces the uncertainty
associated to lab to field differences in food intake ratios, will be used in the risk assessment.
Hence, the calculated ENEL will be used and compared to an Exposure Level (EL).
According to EUBEES 2 the worst case may be considered as a portion of 600 g bait as the normal
upper limit for what is available to non-target animals. However, it is important that the assessor
checks the use conditions in a given area/country before the upper limit for what is available to nontarget animals is estimated. Thus the concentration of the rodenticide in the food of a non-target
organism (EL) is the concentration of the active substance in the rodenticide bait to be taken up by
the non-target animal 600 g at maximum in one daily meal.
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ANNEX: Assessing the environmental risk for primary and secondary poisoning in birds and mammals of the rodenticide chlorophacinone
Tier 1 primary poisoning to mammals
Table 3. Tier 1 of primary poisoning to mammals. Risk characterisation (wax block 0.005%). Single-dose exposure
assessment.
g bait
(0.005%) per
Maximum oral daily intake
ENEL
day ingested by
Organism
(mg a.s·kg bw-1·d-1)
EL/ENEL
(mg a.s·kg bw -1·d-1)
non-target
EL = ETE
mammal to
pose a risk
Dog (10 kg)
3
« 0.05
» 60
«10
Pig (80 kg)
0.4
« 0.05
» 8.0
«79
Pig young (25 kg)
1.2
« 0.05
» 24
«25
Tier 1 primary poisoning to birds
Table 4. Tier 1 of primary poisoning to birds. Risk characterisation (wax block 0.005%). Single-dose exposure assessment.
Maximum oral daily intake
g bait (0.005%) per day
ENEL
Organism
(mg a.s·kgbw-1·d-1)
EL/ENEL
ingested by non-target bird
-1
-1
(mg a.s·kgbw ·d )
EL
to pose a risk
Tree sparrow (22 g)
1,364
6.42
2.8
212.5
Chaffinch (21.4 g)
1,402
6.42
2.7
218.4
Wood pigeon (300 g)
100
6.42
38.5
15.6
Pheasant (953 g)
31
6.42
123.1
4.8
A second tier has been carried out in order to refine the calculations and be more realistic. The
authors have performed for this second tier the additional estimation of the risks for a single dose
(acute), a five-days dose (short-term) and the long-term exposure.
Tier 2, primary poisoning
For small non-target mammals and birds it is assumed that exposure to the full amount of
chlorophacinone at secured bait points over a period of days will result in death. Exposure to an
amount less than the full dosage placed at secured bait points may cause significant harm to small
non-target animals. Domestic animals may accidentally ingest parts of bait blocks discarded outside
the secured bait points. The bodyweights, daily food intakes and estimates of chlorophacinone
ingestion, based on sufficient bait blocks being accessible to satisfy a day’s food intake
requirement, are presented below for a range of non-target mammals and birds based on the
equation ETE = (FIR/BW)·C·AV·PT·PD (mg a.s·kg bw-1·d-1). In the first tier (worst case scenario)
AV is the avoidance factor (default value 1.0 = no avoidance), PT is the fraction of diet obtained in
the treated area (default value 1.0) and PD is the fraction of food type in the diet (default value 1.0).
In the second tier (realistic worst case scenario) AV = 0.9, PT = 0.8 and PD =1.
Primary poisoning for mammals. Tier 2
Table 5. Tier 2. Risk characterisation for different primary poisoning scenarios to mammals (wax block 0.005%)
EL = ETE (mg a.s·kg bw -1·dEL/ENEL
1)
% DFI to
Exposure scenario
pose
a risk
g contaminated
(species, ENEL
First tier*
First tier
for nonfood per day to
target
pose a risk
mammals
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ANNEX: Assessing the environmental risk for primary and secondary poisoning in birds and mammals of the rodenticide chlorophacinone
Single-dose exposure assessment
3.0
« 1.7
» 60.0
0.4
« 13.2
» 7.6
1.2
« 4.2
» 24.0
Short-term exposure assessment
Dog (0.00125 mg a.s·kg bw-1·d-1)**
3.0
0.04
2,400.0
Pig (0.00125 mg a.s·kg bw-1·d-1)**
0.4
0.31
320.0
Pig, young (0.00125 mg a.s·kg bw-1·d-1)**
1.2
0.10
960
Long-term exposure assessment
Dog (0.00017 mg a.s·kg bw-1·d-1)**
3.0
0.006
17,647.0
Pig (0.00017 mg a.s·kg bw-1·d-1)**
0.4
0.043
2,352.9
Pig, young (0.00017 mg a.s·kg bw-1·d-1)**
1.2
0.014
7,058.8
*First tier AV=1 PT=1; Second tier AV=0.9, PT=0.8 corrected for a maximum ingestion of 600 g bait.
**No daily mean food intake stated in the EUBEES-ESD: simplistically, a maximum bait consumption of 600 g
rodenticide bait 0.005%.
Dog (« 0.05 mg a.s·kg bw-1·d-1)**
Pig (« 0.05 mg a.s·kg bw-1·d-1)**
Pig, young (« 0.05 mg a.s·kg bw-1·d-1)**
« 10.2
« 79.2
« 25.2
0.24
1.86
0.60
0.036
0.258
0.084
is assumed in
Primary poisoning for birds. Tier 2
Table 6. Tier 2. Primary poisoning. Expected content of the active substance chlorophacinone in non-target animals (birds) in
the worst case situation (wax block 0.005%).
Daily
Estimated daily uptake of a.s, ETE
Body
Food
Bait
(mg a.s·kgbw-1·d-1)
Organism
Species
Weight
Intake
consumption
(g)
(g·d-1)
first tier*
Tree sparrow
Passer montanus
22
7.6
7.6
17.3
Chaffinch
Fringilla coelebs
21.4
6.42
6.42
15.0
Wood pigeon
Columba palumbus
490
53.1
53.1
5.4
Pheasant
Phasianus colchicus
953
102.7
102.7
5.4
*first tier (worst case) AV, PT and PD = 1.
Table 7. Tier 2. Risk characterisation for different primary poisoning scenarios to birds (wax block 0.005%)
EL=ETE (mg a.s·kgbw-1·d-1)
Exposure scenario
(species, ENEL)
Tree sparrow (22 g) (ENEL = 6.42 mg
a.s·kg bw-1·d-1)
Chaffinch (21.4 g) (ENEL = 6.42 mg a.s·kg
bw-1·d-1)
Wood pigeon (490 g) (ENEL = 6.42 mg
a.s·kg bw-1·d-1)
Pheasant (953 g) (ENEL = 6.42 mg a.s·kg
bw-1·d-1)
Tree sparrow (22 g) (ENEL = 0.43 mg
a.s·kg bw-1·d-1)
Chaffinch (21.4 g) (ENEL = 0.43 mg a.s·kg
bw-1·d-1)
Wood pigeon (490 g) (ENEL = 0.43 mg
a.s·kg bw-1·d-1)
Pheasant (953 g) (ENEL = 0.43 mg a.s·kg
bw-1·d-1)
First tier*
EL/ENEL
First tier
Single-dose exposure assessment
17.3
% DFI to
pose a
risk for
nontarget
birds
g
contaminated
food per day
to pose a risk
2.7
37.0
2.8
15.0
2.3
43.5
2.79
5.4
0.8
5.4
0.8
40.2
2.5
0.19
15.0
34.9
2.9
0.19
5.4
12.6
7.9
4.20
5.4
12.6
7.9
8.11
Short-term exposure assessment
17.3
Long-term exposure assessment
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ANNEX: Assessing the environmental risk for primary and secondary poisoning in birds and mammals of the rodenticide chlorophacinone
Tree sparrow (22 g) (ENEL = 0.017 mg
a.s·kg bw-1·d-1)
Chaffinch (21.4 g) (ENEL = 0.017 mg
a.s·kg bw-1·d-1)
Wood pigeon (490 g) (ENEL = 0.017 mg
a.s·kg bw-1·d-1)
Pheasant (953 g) (ENEL = 0.017 mg a.s·kg
bw-1·d-1)
*first tier (worst case) AV, PT and PD = 1.
17.3
1,017.6
0.10
0.0076
15.0
882.4
0.11
0.0071
5.4
317.6
0.31
0.164
5.4
317.6
0.31
0.318
Taking into account the estimated daily uptake of the compound (ETE) the ratios above 1
correspond to the smallest birds in an acute situation, what means that there is a potential risk to
those birds. But for the big ones, the ratio is above one. So, small birds are potentially most at risk
for primary poisoning in acute exposures. But on the other hand when there is a short and long-term
exposure, all birds are potentially at risk.
As a general conclusion for primary poisoning, except birds who eat less than about 11% of their
body weight, the rest of the birds and all the mammals present a potential risk for primary
poisoning. Small mammals and birds are potentially most at risk of primary poisoning and
mammals more than birds.
To minimise the likelihood of target rodents developing resistance to anticoagulant rodenticides,
long-term deployment of bait blocks as a preventative control measure is not recommended.
Product labels additionally instruct users to retrieve and securely dispose of all unconsumed baits at
the end of control programmes. Both these factors limit the opportunity for exposure and reduce the
primary poisoning risk to small non-target animals. The assessor should check what the exposure
would be if the label conditions are followed. The reason is to assure that label instructions are fully
adequate to mitigate intrinsic risk that these products potentially present (ESD, EUBEES 2).
Secondary poisoning
Rodents targeted by indoor and outdoor baiting campaigns are likely to roam outdoors and within
the hunting ranges of predatory birds and mammals. Target animals that succumb to the effects of
anticoagulant rodenticides and die whilst foraging outdoors may be found and ingested by
scavenging vertebrates. A potential for secondary poisoning of birds and mammals therefore exists,
even (though to a lesser extent) on occasions when the deployment of bait blocks containing
chlorophacinone is confined to the interiors of buildings.
EUBEES 2 cites three published reports of cage and enclosure studies in which the authors
observed behavioural changes in poisoned rodents that would appear to increase their susceptibility
to predation during daytime and also the likelihood that fatal haemorrhage would occur while the
rodents were away from shelter, leaving their carcasses exposed to scavengers (study from the RAR
of chlorophacinone. July 2008).
In accordance with EUBEES 2 guidance, the following assessment of secondary poisoning takes
into account the levels of chlorophacinone residues in target rodents, based on its concentration in
bait blocks, feeding (chlorophacinone intake) and excretion (chlorophacinone elimination) rates of
target rodents, as well as the period over which the bait is eaten before the effects of poisoning
inhibit further feeding. These combined factors form the basis of exposure to predators and
scavengers upon which to assess risk.
The ETE values for rodents (mice and rats) are based on three theoretical levels of ingestion of bait
blocks constituting 100%, 50% and 20% of the daily food intake (to allow for various intakes of
INIA Report. Department of the Environment, Division of Ecotoxicology and Environmental Risk Assessment
Page 10 of 18
ANNEX: Assessing the environmental risk for primary and secondary poisoning in birds and mammals of the rodenticide chlorophacinone
alternative foods), a FIR·kgbw-1 of 0.1 for rats and mice and a concentration of chlorophacinone in
bait block equal to 50 mg a.s·kgproduct-1. The ETE values are therefore 5.0, 2.5, 1.00 mg a.s·kgbw for
levels of bait consumption equivalent to 100%, 50% and 20% of daily food intake, respectively.
Only the intermediate case will be depicted for a conservative approach.
The default rate of elimination of residues from the bodies of target rodents is 30% per day (faecal
route only). The elimination of residues has been measured from a pair of male rats fed with
approximately 5.0 mg a.s·kgbw-1. Severe haemorrhaging occurred and the test rats eventually died.
Significant metabolites of chlorophacinone were identified. The default daily elimination rate of
30% for anticoagulant rodenticides prescribed by EUBEES 2 is in general in accordance with the
mean values measured for chlorophacinone, which averaged 33.5% over the first three days and
ranged from 37.6% for day 1 to 52.8% for day 2.
Table 8. Elimination of chlorophacinone residues (14C-equivalents) from male rats (from RAR CPN Doc. II-A, Section 6.201)*
Radioactivity excreted
(mean % of applied, estimated dose approximately 5.0 mg·kg bw-1)
Sampling time (days)
Urine
Faeces
Volatiles
Total
1
0.383
37.19
0.025
37.6
2
0.241
52.54
0.013
52.8
3
0.082
10.08
0.004
10.2
4
0.052
1.8
0.006
1.9
Cumulative 3 day total
0.706
99.81
0.042
100.6
Cumulative 4 day total
0.758
101.61
0.048
102.4
1 Based on individual doses of 1.43 and 1.28 mg 14C-chlorophacinone per animal, individual bw not stated, range 200 to 250 g.
* Data from the risk assessment report for chlorophacinone. July 2008.
The residue levels are also based on an assumption that ingestion of chlorophacinone in bait blocks
occurs consistently during the first five days of baiting and that feeding (including bait ingestion)
ceases on day 6, followed by death on day 7. However, the time to death under more realistic
conditions may differ from that observed in the laboratory if the target rodents have unrestricted
access to alternative food(s). EUBEES 2 considers three levels of bait consumption by target
rodents, expressed in terms of bait ingestion as a percentage of total daily food intake. A level of
20% is regarded as the minimum for an effective bait formulated to appeal to target rodents, whilst
100% represents the realistic worst-case view. In the presence of other, competing food sources
(presumed to be present to allow a population of target rodents to become established), an intake of
around 50% may be more likely. Therefore calculations for a 50% intake will be depicted.
The equation ETE = (FIR/BW)·C·AV·PT·PD (mg kgbw-1·d-1) for primary poisoning can be used for
calculating the amount of active substance being consumed by the target rodent. EC is the estimated
residue concentration in the rat. FIR/BW = 0.1 as default value; it is assumed that rats eat 10% their
own weight.
INIA Report. Department of the Environment, Division of Ecotoxicology and Environmental Risk Assessment
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ANNEX: Assessing the environmental risk for primary and secondary poisoning in birds and mammals of the rodenticide chlorophacinone
Table 9. Residues of chlorophacinone in target rodents from the ingestion of bait blocks at different times during a control
campaign, calculated according to EUBEES 2. Used in the secondary poisoning short-term (one single dose) exposure of the
predator.
ECn
Residues of chlorophacinone in target rodent
Time
(mg a.s·kg rat bw-1 = mg a.s·kg food-1)
A normal non-resistant target rodent stops eating on day 5
100% bait consumption (RWC)
No resistance situation
EC1 Day 1, before first meal
5.0
EC5 Day 5 before last meal
8.9
EC5+ETE = PECoral predator
13.9
Day 5 after last meal without elimination
EC6 Day 6 no feeding
9.7
EC7 Day 7 (mean time to death)*
6.8
Resistance situation
EC14 Day 14 just in case of resistance**
16.6
* The feeding period has been set to a default value of 5 days until the onset of symptoms after which the rodent eats nothing until its
death.
** no resistance has been detected for chlorophacinone.
Calculated residue patterns suggest that levels increase following each daily intake until day 5 after
last meal before they are going to die, after which the rodents are assumed to eat no more bait
blocks, but to continue to excrete residues at approximately 30% per day, resulting in a reduction of
residues by approximately half between the last intake on day 5 and death on day 7.
Secondary poisoning assessment according to the TGD (2003) considers the oral intake of a
chemical via fish or worms only (PECoral, fish and PECoral, worm) which is compared to a PNEC for
fish- or worm-eating mammals or birds. Therefore, another food chain rodenticide (bait)  rodent
 rodent-eating mammal or rodent-eating bird is assessed here.
Tier 1: Realistic worst case scenario
PECoral,predator = (ECn + ETE) · Frodent
ECn is the expected concentration of a.s. in the rodent on day “n” BEFORE the last meal (mg·kg
bw-1)
ETE is the estimated uptake of active substance by rodent on day “n” (i.e. intake of rodenticide in
the last meal, no elimination)
Frodent is the fraction of poisoned rodents in predator’s diet 1 for short-term exposure and 0.5 for
long-term exposure.
Secondary poisoning to mammals. Tier 1
For the single-dose exposure one rat carcass of 300 g is assumed to be eaten by the non-target
vertebrate, since it is the most likely situation. It implies that 4.17 mg of chlorophacinone is the
residue the non-target vertebrates ingest. The amount of ingested contaminated rat is dismissed to
the daily food intake for small vertebrates.
INIA Report. Department of the Environment, Division of Ecotoxicology and Environmental Risk Assessment
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ANNEX: Assessing the environmental risk for primary and secondary poisoning in birds and mammals of the rodenticide chlorophacinone
Table 10. Tier 1 for secondary poisoning for non-target mammals. Risk characterisation.
Bait consumption
ELpredator
(mg a.s·kg
-1
predator bw )
ENEL
(mg a.s·kg predator
-1 -1
bw ·d )
EL/ENEL
g
contaminate
d rat to pose
a risk
Single-dose exposure assessment*
Based on maximum residues in the rat after 5 days of ingestion after last meal. No resistance situation*
Fox Vulpes vulpes (5,700 g; DFI = 520.2 g food·d-1. 300 g
0.73
« 0.05
« 20.5
» 14.6
rat ingested = 4.17 mg a.s.)
Polecat Mustela putorius (689 g; DFI = 130.9 g food·d-1;
2.64
« 0.05
« 2.48
» 52.8
130.9 g rat ingested = 1.82 mg a.s.)
Stoat Mustela erminea (205 g; DFI = 55.7 g food·d-1; 55.7 g
3.76
« 0.05
« 0.74
» 75.12
rat ingested = 0.77 mg a.s.)
Weasel Mustela nivalis (63 g; DFI = 24.7 g food·d-1; 24.7 g
5.40
« 0.05
« 0.23
» 107.94
rat ingested = 0.34 mg a.s.)
*Ingestion of a maximum of 300 g contaminated rat, equivalent to 4.7 mg a.s (based on the residues in rats after 5 days of
exposure after last meal without elimination of 13.9 mg a.s·kg rat -1, 100% bait consumption, RWC). The amount of ingested
contaminated rat is dismissed to the daily food intake for small vertebrates.
All EL/ENEL ratios are far above one indicating that there is a potential acute risk of secondary
poisoning to mammals even from a single contaminated rat. Therefore for this tier no short or longterm risk assessment of secondary poisoning will be calculated.
Primary poisoning for birds. Tier 1
Table 11. Tier 1 for secondary poisoning for non-target birds. Risk characterisation.
EL
ENEL
(mg a.s·kg predator
(mg a.s·kg predator
Bait consumption
EL/ENEL
bw-1)
bw-1)
Single-dose exposure assessment*
Based on maximum residues in the rat after 5 days of ingestion after last meal. No resistance situation
Barn owl Tyto alba (294 g bw; DFI = 72.9 g food·d-1;
3.45
6.42
0.54
72.9 g rat ingested = 1.01 mg a.s.)
Kestrel Falco tinnunculus (209 g bw; DFI = 78.7 g
5.23
6.42
0.82
food·d-1; 78.7 g rat ingested = 1.09 mg a.s.)
Little owl Athene noctua (164 g bw; DFI = 46.4 g
3.93
6.42
0.61
food·d-1; 46.4 g rat ingested = mg a.s.)
Tawny owl Strix aluco (426 g bw; DFI = 97.1 g food·d3.17
6.42
0.49
1; 97.1 g rat ingested = mg a.s.)
Short-term exposure assessment**
g contaminated
rat to pose a risk
Based on maximum residues in the rat after 5 days of ingestion after last meal. No resistance situation
100% Barn owl Tyto alba (294 g bw; DFI = 72.9 g food
3.45
0.43
9.09
8.02
(rat in this case)
100% Kestrel Falco tinnunculus (209 g bw; DFI = 78.7
5.23
0.43
6.46
12.17
g food·d-1)
100% Little owl Athene noctua (164 g bw; DFI = 46.4 g
3.93
0.43
5.07
9.14
food)
100% Tawny owl Strix aluco (426 g bw; DFI = 97.1 g
3.17
0.43
13.18
7.37
food)
* Ingestion of a maximum of 300 g contaminated rat, equivalent to 4.7 mg a.s (based on the residues in rats after 5 days of exposure
after last meal without elimination of 13.9 mg a.s·kg rat -1, 100% bait consumption, RWC). The amount of ingested contaminated rat
is dismissed to the daily food intake for small vertebrates.
** Based on a PECoral predator of 13.9 mg a.s·kg rat bw-1, for a bait consumption of 100%
A potential risk associated to the consumption of contaminated rats during a short period of time
has been identified, however, the exposure level is below the reported lethality threshold for birds.
Two short-term dietary semi-field studies are available, Doc. III-A 7.5.6-01 Pica pica and III-A
7.5.6-02 ferrets, Mustela putorius furo, where there is a significant risk of secondary poisoning for
mammals (55% mortalities) and a much lower risk to birds (no mortalities reported).
INIA Report. Department of the Environment, Division of Ecotoxicology and Environmental Risk Assessment
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ANNEX: Assessing the environmental risk for primary and secondary poisoning in birds and mammals of the rodenticide chlorophacinone
Tier 2 of secondary poisoning with measured residues of chlorophacinone in target rodents
In the table below the various concentrations of chlorophacinone in target rodents on day 5 and
day 7 have been lowered pro rata to reflect real, measured residues instead of the estimated values
based on kinetics.
Table 12. Residues of chlorophacinone in target rodents from the ingestion of bait blocks at different times during a control
campaign, based on the maximum residue level measured in rats (measured in homogenised whole-body tissues of rat
carcasses).*
Residues of chlorophacinone in target rodent (mg a.s·kg rat bw-1) ECrefined
Time
20% bait consumption
50% bait consumption
100% bait consumption
Day 5 after last meal1
0.19
0.46
0.93
Day 7 (mean time to death)2
0.10
0.24
0.47
1
Based on 0.9272 mg·kgbw-1 measured after 100% bait consumption for 5 days (see Doc. III-A 7.5.6-01);
2 Based on excretion of 30% per day and a reduction of approximately 50% between days 5 and 7.
* Data from the risk assessment report for chlorophacinone. July 2008.
INIA Report. Department of the Environment, Division of Ecotoxicology and Environmental Risk Assessment
Page 14 of 18
ANNEX: Assessing the environmental risk for primary and secondary poisoning in birds and mammals of the rodenticide chlorophacinone
Secondary poisoning for mammals. Tier 2.Table 13. Tier 2 for secondary poisoning for non-target mammals (on day 5 and 7 of a control campaign) containing
chlorophacinone obtained from areas in and around buildings. Risk characterisation.
EL predator
ENEL
% DFI to pose a risk
g contaminated rat
(mg a.s·kg
(mg a.s·kg predator
Bait consumption
EL/ENEL
for non-target
to pose a risk
predator bw-1)
bw-1)
mammals
Single-dose exposure assessment
Based on residues in the rat after 5 days of ingestion after last meal (20-100% bait consumption of the rat).
Fox Vulpes vulpes (5,700 g; DFI = 520.2 g
food·d-1; 300 g rat ingested = 0.06-0.28 mg
0.01-0.05
« 0.05
» 0.21-»0.98
a.s. ingested, rat ingested 20% of bait and
the second value, rat ingested 100% of bait)
Polecat Mustela putorius (689 g; DFI =
130.9 g food·d-1; 130.9 g rat ingested =
0.036-0.18
« 0.05
» 0.72-»3.53
«28.3
« 37.08
0.025-0.121 mg a.s ingested)
Stoat Mustela erminea (205 g; DFI = 55.7
0.052-0.25
« 0.05
» 1.03-»5.05
«19.8- «97.1
« 54.08- «11.03
g·d-1; 55.7 g rat = 0.010-0.052 g a.s.)
Weasel Mustela nivalis (63 g; DFI = 24.7 g
0.074-0.36
« 0.05
» 1.49-»7.29
«13.7- «67.1
«3.39- «16.58
food·d-1; 24.7 g rat = 0.0047-0.023 mg a.s)
Short-term exposure assessment
Based on maximum residues in the rat after 5 days of ingestion after last meal.
100% Fox Vulpes vulpes (5,700 g; DFI =
0.085**
520.2 g food (rat in this case)·d-1)
100% Polecat Mustela putorius (689 g; DFI
0.18**
= 130.9 g food·d-1)
100% Stoat Mustela erminea (205 g; DFI =
0.25**
55.7 g food·d-1)
100% Weasel Mustela nivalis (63 g; DFI =
0.36**
24.7 g food·d-1)
Based on maximum residues in the rat after 7 days of ingestion.
0.0125
6.8
14.7
76.61
0.0125
14.1
7.1
9.26
0.0125
20.2
5.0
2.76
0.0125
29.2
3.4
0.85
100% Vulpes vulpes
0.04***
0.0125
3.4
29.1
151.60
100% Mustela putorius
0.09***
0.0125
7.1
14.0
18.32
100% Mustela erminea
0.13***
0.0125
10.2
9.8
5.45
100% Mustela nivalis
0.18***
0.0125
14.7
6.8
1.68
Long-term exposure assessment
Based on maximum residues in the rat after 5 days of ingestion after last meal.
100% Fox Vulpes vulpes (5,700 g; DFI =
0.085**
520.2 g food (rat in this case)·d-1)
100% Polecat Mustela putorius (689 g; DFI
0.18**
= 130.9 g food·d-1)
50% Stoat Mustela erminea (205 g; DFI =
0.25**
55.7 g food·d-1)
100% Weasel Mustela nivalis (63 g; DFI =
0.36**
24.7 g food·d-1)
Based on maximum residues in the rat after 7 days of ingestion.
0.00017
500.0
0.2
1.04
0.00017
1,058.8
0.09
0.12
0.00017
1,470.6
0.068
0.038
0.00017
2,117.6
0.047
0.012
100% Vulpes vulpes
0.04***
0.00017
235.3
0.42
2.21
100% Mustela putorius
0.09***
0.00017
529.4
0.19
0.25
100% Mustela erminea
0.13***
0.00017
764.7
0.13
0.07
100% Mustela nivalis
0.18***
0.00017
1,058.8
0.09
0.023
* Ingestion of a maximum of 300 g contaminated rat, equivalent to 0.279 mg a.s/0.057 mg a.s. (based on the residues in rats after 5
days of exposure after last meal without elimination of 0.93 mg a.s·kg rat -1/0.19 mg a.s·kgrat-1, 100% (RWC) and 20% bait
consumption, respectively). The amount of ingested contaminated rat is dismissed to the daily food intake for small vertebrates
** Based on a PECoral predator of 0.93 mg a.s·kg rat bw-1, for a bait consumption of 100%
*** Based on a PECoral predator of 0.47 mg a.s·kg rat bw-1, for a bait consumption of 100%
INIA Report. Department of the Environment, Division of Ecotoxicology and Environmental Risk Assessment
Page 15 of 18
ANNEX: Assessing the environmental risk for primary and secondary poisoning in birds and mammals of the rodenticide chlorophacinone
Secondary poisoning for birds. Tier 2
Table 14. Tier 2 for secondary poisoning for non-target birds containing chlorophacinone obtained from areas in and around
buildings. Risk characterisation.
% DFI to
ENEL
ELpredator
pose a risk
(mg
g contaminated
(mg a.s·kg
Bait consumption
EL/ENEL
for nona.s.·kgpredator
rat to pose a risk
-1)
target
predator bw
-1
bw )
mammals
Single-dose exposure assessment
Based on residues in the rat after 5 days of ingestion after last meal (20-100% bait consumption of the rat).
Barn owl Tyto alba (294 g bw; DFI = 72.9 g food (rat in
this case)·d-1; 72.9 g rat ingested = 0.057-0.279 mg a.s.
0.19-0.94*
6.42
0.030-0.15
ingested)
Kestrel Falco tinnunculus (209 g bw; DFI = 78.7 g
food·d-1; 78.7 g rat ingested = 0.015-0.073 mg a.s.
0.07-0.35*
6.42
0.011-0.054
ingested)
Little owl Athene noctua (164 g bw; DFI = 46.4 g food·d0.05-0.26*
6.42
0.084-0.041
1; 46.4 mg rat ingested = 0.0088-0.043 mg a.s. ingested)
-1
Tawny owl Strix aluco (426 g bw; DFI = 97.1 g food·d ;
0.04-0.21*
6.42
0.066-0.033
97.1 g rat ingested = 0.018-0.090 mg a.s. ingested)
Short-term exposure assessment
Based on maximum residues in the rat after 5 days of ingestion after last meal.
100% Barn owl Tyto alba (294 g bw; DFI = 72.9 g food
0.23**
(rat in this case))
100% Kestrel Falco tinnunculus (209 g bw; DFI = 78.7 g
0.35**
food·d-1)
100% Little owl Athene noctua (164 g bw; DFI = 46.4 g
0.26**
food·d-1)
100% Tawny owl Strix aluco (426 g bw; DFI = 97.1 g
0.21**
food·d-1)
Based on maximum residues in the rat after 7 days of ingestion.
0.43
0.54
0.43
0.81
0.43
0.61
0.43
0.49
100% Tyto alba
0.12***
0.43
0.27
100% Falco tinnunculus
0.18***
0.43
0.41
100% Athene noctua
0.13***
0.43
0.31
100% Strix aluco
0.11***
0.43
0.25
Long-term exposure assessment
Based on maximum residues in the rat after 5 days of ingestion after last meal.
100% Barn owl Tyto alba (294 g bw; DFI = 72.9 g food
0.23**
(rat in this case)·d-1)
100% Kestrel Falco tinnunculus (209 g bw; DFI = 78.7 g
0.35**
food·d-1)
100% Little owl Athene noctua (164 g bw; DFI = 46.4 g
0.26**
food·d-1)
100% Tawny owl Strix aluco (426 g bw; DFI = 97.1 g
0.21**
food·d-1)
Based on maximum residues in the rat after 7 days of ingestion.
0.017
13.52
7.39
5.39
0.017
20.59
4.86
3.82
0.017
15.29
6.54
3.03
0.017
12.35
8.10
7.86
100% Tyto alba
0.12***
0.017
7.06
14.17
10.33
100% Falco tinnunculus
0.18***
0.017
10.59
9.44
7.43
100% Athene noctua
0.13***
0.017
7.65
13.08
6.07
100% Strix aluco
0.11***
0.017
6.47
15.45
15.01
* Ingestion of a maximum of 300 g contaminated rat, equivalent to 0.279 mg a.s/0.057 mg a.s. (based on the residues in rats after 5
days of exposure after last meal without elimination of 0.93 mg a.s·kg rat-1/0.19 mg a.s·kg rat-1, 100% (RWC) and 20% bait
consumption, respectively). The amount of ingested contaminated rat is dismissed to the daily food intake for small vertebrates
** Based on a PECoral predator of 0.93 mg a.s·kg rat bw-1, for a bait consumption of 100%
*** Based on a PECoral predator of 0.47 mg a.s·kg rat bw-1, for a bait consumption of 100%
Making use of the measured residues of chlorophacinone in target rodents from the ingestion of bait
blocks at different times during a control campaign, based on the maximum residue level measured
INIA Report. Department of the Environment, Division of Ecotoxicology and Environmental Risk Assessment
Page 16 of 18
ANNEX: Assessing the environmental risk for primary and secondary poisoning in birds and mammals of the rodenticide chlorophacinone
in rats, there is no risk of neither in the acute nor in the short-term exposure of secondary poisoning
to birds. The refinement has lowered the ratios several times but there is still a long-term risk of
secondary poisoning to birds.
HIGHER TIER ASSESSMENT
Two relevant pieces of information are available for a higher tier assessment. A semifield study
with 5 days exposure, (study from the chlorophacinone RAR, draft July 2008); and a monitoring
study following the use of chlorophacinone for controlling a rodent pest of Microtus arvalis in a
large rural area in Spain.
As presented in the effect data assessment the semifield study confirmed the coherence of the
toxicological profile of the molecule, allowing a preliminary critical body burden assessment, fully
in line with the outcome of the lab studies.
In addition, the role of lethality as relevant endpoint even for the assessment of chronic effects, and
the relatively low sensitivity of birds compared to mammals were confirmed.
The concentrations measured in Microtus arvalis collected in the field are presented in table 3.
Table 15. concentrations measured in Microtus arvalis
% of sampled organisms with detected concentrations
Sampling point
mg a.s·kgwwt-1
75 %
Area A
Min. 0.10
Max. 0.29
17%
Area B
Min. 0.27
Max. 0.52
0%
Area C
Not detected
The comparison of these estimations with the toxicological effect assessment endpoints confirms
that the mortality of several collected animals can be directly associated with the consumption of
chlorophacinone and that the residual content in the carcasses of dead animals after the field use
represents a significant risk for predatory mammals.
Preliminary exposure thresholds can be determined on the basis of the food intake rate of rodent
carcasses (weight of consumed carcasses/body weight). The lethality threshold for repeated
exposures is estimated at a rate of 0.02 (2%), while a 0.1 value (10%) would represent around a
50% mortality, based on the sensitivity of the tested species. Considering the additional uncertainty
associated to interspecies extrapolation, any value above 0.0025 (0.25%) would represent a
potential risk of secondary poisoning associated to the consumption of the pest carcasses.
INIA Report. Department of the Environment, Division of Ecotoxicology and Environmental Risk Assessment
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ANNEX: Assessing the environmental risk for primary and secondary poisoning in birds and mammals of the rodenticide chlorophacinone
LIST OF ABBREVIATIONS
BW
CAR
CPN
DFI
EL
LOAEL
NOAEL
NOEC
ENEL
ESD
RAR
RWC
TGD
Body Weight
Competent Authority Report
Chlorophacinone
Daily Food Intake
Exposure Level
Lowest Observed Adverse Effect Level
No Observed Adverse Effect Level
No Observed Effect Concentration
Estimated No Effects Levels
Emission Scenario Document
Risk Assessment Report
Realistic Worst Case
Technical Guidance Document
REFERENCES
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mouse tissue. J. Asoc. Off Anal. Chem. 65 (5) : 1299-1301.
Chlorophacinone. Draft Risk Assessment Report. European Chemicals Bureau. July 2008.
ECB, 2003 ECB (European Chemicals Bureau) (2003). 2 nd edition of the Technical Guidance Document (TGD) on Risk
Assessment of Chemical Substances following European
EUBEES 2, ESD. CA-Jun03-Doc.8.2-PT14. Danish EPA. J. Larsen. Supplement to the methodology for risk evaluation
of biocides. Emission scenario document for biocides used as rodenticides. May 2003.
Marek L.J., Koskinen WC. (2007). Multirresidue analysis of seven anticoagulant rodenticides by high-performance
liquid chromatography/electrospray/Mass Spectrometry. J. Agric. Food Chem. 55:571-576.
Palazoglu M.G., Tor E.R., Holstege D.M., Galey F.D. (1998). Multirresidue analysis of nine anticoagulant rodenticides
in serum. J. Agric. Food Chem. 46:4260-4266
Primus Th.M., Eisemann J.D., Matschke G.H., Ramey C., Johnston J.J. (2001). Chlorophacinone residues in Rangeland
rodents: Am assessment of the potential risk of secondary toxicity to scavengers. En: Pesticides and Wildlife.
Editor: Johnston J.J. ACS Symposium Series 771. American Chemical Society. Washington DC. Pp. 164-180.
SSC (2003). Second Report on the Harmonization of Risk Assessment Protocols. Scientific Steering Committee,
European Commission. (Publication in the official web page of the European Union in May 2003; pending on
paper publication). European Commission. Brussels.
TGD, 2003. Technical Guidance Document on Risk assessment in support of Commission Directive 93/67/EEC on Risk
Assessment for new notified substances, Commission Regulation (EC) nº 1488/94 on Risk Assessment for
existing substances and Directive 98/8/EC of the European Parliament and of the Council concerning the placing
of biocidal products on the market. European Commission. Joint Research Centre. EUR 20418 EN/2.
USEPA (1998). Guidelines for Ecological Risk Assessment (Published on May 14, Federal Register 63(93):2684626924).Risk Assessment Forum. US Envrionmental Protection Agency, Washing ton, D.C.
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