FINAL SCIENCE MEMO
APP202697 – Para-Ken 250 Herbicide
Substance database ID - 48033
April 2016
Project team:
Application advisor: Trudy Geoghegan
Toxicologist: Stuart Creton
Ecotoxicologist: Miguel Santos
Peer-reviewer: Cora Drijver (consultant for the ecotox); Jeane Nicolas (tox)
2
1. Executive summary
1.1. Background and justification for a Cat B standard pathway
1.1.1 Para-Ken 250 Herbicide is a soluble concentrate containing paraquat dichloride as the active
ingredient, plus other components. It is intended for use as an herbicide for the control of weeds in
Lucerne, Clover seed crops, Forestry, Industrial site, Streets and for Barley grass control.
1.1.2 Para-Ken 250 Herbicide was originally submitted as a Rapid application (APP202591). However it was
declined under this pathway due to international concerns regarding the safety of paraquat for
human health and the environment. Paraquat is banned in the EU and has been either banned or
severely restricted in a number of other countries.
Human health
1.1.3
Para-Ken 250 Herbicide is proposed to be used at a similar application rate to other approved
substances containing paraquat dichloride. However, due to international concerns regarding the
safety of paraquat a quantitative human health risk assessment was undertaken.
Ecotox
1.1.4
Para-Ken 250 Herbicide contains paraquat dichloride and is proposed to be used at a similar
application rate to other approved substances containing paraquat dichloride. However, due to
international concerns regarding the safety of paraquat a quantitative environmental risk assessment
was undertaken.
1.2. Key points
1.2.1 The applicant classified Para-Ken 250 Herbicide as follows: 6.1B (O), 6.1B (D), 6.1A (Inh), 6.3A, 6.4A,
6.9A, 9.1A, 9.3A, 9.4B. The staff classified Para-Ken 250 Herbicide as follows: 6.1C (O), 6.1B (D),
6.1A (I), 6.3A, 6.4A, 9.1A, 9.3A, 9.4B. The difference in the acute oral toxicity classification appears to
be based on a different interpretation of mixture rules by the applicant.
1.2.2 The applicant provided ecotox studies with a formulation containing 20% paraquat dichloride. The
results with the formulation were used for the risk assessment when considered acceptable.
1.2.3 Predicted exposures of operators during mixing, loading and application of Para-Ken 250 Herbicide
are greater than the AOEL for paraquat, even with the use of full PPE including a respirator.
1.2.4 Based on the use pattern re-entry worker exposure to Para-Ken 250 Herbicide is likely to be minimal
and therefore no quantitative re-entry worker exposure assessment has been performed.
1.2.5 Predicted exposures of a bystander 8 metres away from the edge of an application area are greater
than the acceptable levels for both active ingredients. If spraying of Para-Ken 250 Herbicide were
limited to use of coarse droplets, minimum buffer zones of 16 or 30 metres from sensitive areas would
April 2016
3
be required for low boom or high boom application, respectively, in order to reduce exposures to the
AOEL.
1.2.6 Predicted exposures for children playing directly on a treated area (such as children playing on street
verges) are also substantially higher than the AOEL.
1.2.7 Staff consider that the approval of Para-Ken 250 Herbicide as broadcast spray to clover, Lucerne,
forestry and barley grass control should be declined due to the unacceptable risks posed to aquatic
organisms (algae) and birds.
1.2.8 Staff consider that the application of Para-Ken 250 Herbicide as spot treatment (using knapsack in
non-wide dispersive manner) in non-crop situations such as in streets, industrial sites the risks can be
considered below the level of concern in terms of risks to the environment. However, the staff
recommended that the application using knapsack should be carried out using nozzles equipped to
release coarse droplets and thus preventing spray drift.
1.2.9 Although the risks for the environment could be managed by limiting use of Para-Ken 250 Herbicide to
spot treatment, the human health risk assessment indicates that there would still be unacceptable
risks for operators applying the substance by knapsack and potentially for children playing on treated
areas such as street verges. Therefore it is proposed that the application should be declined.
1.2.10 Based on the concerns identified it is proposed that grounds should be sought to reassess Paraquat
and the formulations containing it that are currently approved under HSNO.
1.3. Regulatory status
Table 1 Active ingredient regulatory status
Active ingredient name
Regulatory history in New
International regulatory
Zealand
history
(Australia, Canada, Europe,
Japan, USA)
Paraquat dichloride
Approved in NZ
Approved in Australia, USA and
Canada.
Not approved as a pesticide active
in Europe. Banned or restricted in
a number of other jurisdictions.
April 2016
4
1.4. Use pattern
Table 2 Substance use pattern
Substance category
Wide
Dispersive
use
Concentration
Application
rate(s)
250 g/L
See GAP
Table
Yes
Herbicide
No
April 2016
Remarks
Table 3 GAP table
Crop
and/or
situation
(a)
Clover
seeds
Fence
lines,
Stock
yards,
Street
verges,
Streets
and
Industrial
sites
Product
code
F
G
or
I
(b)
F
Pests or
Group of pests
controlled
Formulation
PHI
Application rate per treatment (days)
Application
(c)
Grasses, Broad
Leaf Weeds
(l)
Type
Conc.
of as
method
kind
(d-f)
(i)
(f-h)
growth
stage &
season
(j)
2 weeks
before
closing
clover
crop for
seed.
250
g/L
High
volume
broadcast
SL
250
g/L
All stages
and
growth
High
seasons
volume
but more
broadcast, predominatel
Handgun,
y in the
Knapsack spring/summ
er/autumn
period
SL
F
Grasses, Broad
Leaf Weeds
Forestry
F
Grasses, Broad
Leaf Weeds
SL
250
g/L
Lucerne
F
Grasses,
Annual Broad
Leaf Weeds
SL
250
g/L
All stages in
High
spring/summ
volume
er/autumn
broadcast
season
Winter while
High
Lucerne is
volume
dormant
broadcast
number
min max
(k)
interval
between
application
s (min)
kg as/hL
water L/ha kg as/ha
min max
min max min max
1-2
28 days
0.1-0.16
250300
0.3-0.4
1-4
28 days
0.1-0.3
5001000
1.0-1.5
1-2
28 days
0.333-0.5
200300
1
1-2
28 days
0.1330.240
250300
0.4-0.6
Remarks:
(m)
Crop
and/or
situation
Product
code
(a)
F
G
or
I
(b)
Pests or
Group of pests
controlled
Formulation
(l)
Type
Conc.
of as
method
kind
(d-f)
(i)
(f-h)
Australia sedges
F
SL
Tall rescue and
rushes
Remarks
Application
(c)
Barley grasses
Non
selective
weed
control
250
g/L
growth
stage &
season
(j)
number
min max
(k)
During the
active
growth
phase of the
target
species
but before 1-4
seed
Handgun
maturity.
Predo
minately in
the
spring/summ
er/autumn
period
(a) For crops, the EU and Codex classifications (both) should be used; where relevant, the use
situation should be described (e.g. fumigation of a structure)
(b) Outdoor or field use (F), glasshouse application (G) or indoor application (I)
(c) e.g. biting and suckling insects, soil born insects, foliar fungi, weeds
(d) e.g. wettable powder (WP), emulsifiable concentrate (EC), granule (GR)
(e) GCPF Codes - GIFAP Technical Monograph No 2, 1989
(f) All abbreviations used must be explained
(g) Method, e.g. high volume spraying, low volume spraying, spreading, dusting, drench
(h) Kind, e.g. overall, broadcast, aerial spraying, row, individual plant, between the plants type of equipment used must be indicated
April 2016
PHI
Application rate per treatment (days)
(i)
(j)
interval
between
application
s (min)
kg as/hL
water L/ha kg as/ha
min max
min max min max
0.06-0.12
5001000
0.6
0.0250.2727
5501000
0.251.5
0.15-0.3
5001000
1.5
Remarks:
(m)
28 days
g/kg or g/l
Growth stage at last treatment (BBCH Monograph, Growth Stages of Plants, 1997,
Blackwell, ISBN 3-8263-3152-4), including where relevant, information on season at time
of application
(k) The minimum and maximum number of application possible under practical conditions of
use must be provided
(l) PHI - minimum pre-harvest interval
(m) Remarks may include: Extent of use/economic importance/restrictions
7
2. Applicant and Staff hazard classifications of the mixture
Table 4 Applicant and Staff classifications of the mixture
Staff’s
classification
Class 1 Explosiveness
NA
ND
Class 2, 3 & 4 Flammability
NA
ND
Class 5 Oxidisers/Organic
Peroxides
NA
Subclass 8.1 Metallic
corrosiveness
NA
Remarks
Mixture
rules1
Applicant’s
classification
Read across
Hazard Class/Subclass
Method of
classification
Mixture data
Mixture classification
ND
ND
Mainly paraquat
dichloride
Difference
appears to be a
different
interpretation of
mixture rules
Subclass 6.1 Acute toxicity (oral)
6.1B
6.1C
Subclass 6.1Acute toxicity
(dermal)
6.1B
6.1B
Mainly paraquat
dichloride
Subclass 6.1 Acute toxicity
(inhalation)
6.1A
6.1A
Paraquat
dichloride
Subclass 6.1 Aspiration hazard
NA
ND
Subclass 6.3/8.2 Skin
irritancy/corrosion
6.3A
6.3A
Paraquat
dichloride
Subclass 6.4/8.3 Eye
irritancy/corrosion
6.4A
6.4A
Mainly paraquat
dichloride
Subclass 6.5A Respiratory
sensitisation
NA
Subclass 6.5B Contact
sensitisation
NA
Subclass 6.6 Mutagenicity
NA
ND
Subclass 6.7 Carcinogenicity
NA
ND
1
ND
ND
Use of mixture rules may not adequately take into account interactions between different components in some circumstances
and must be considered of lower reliability than data on the mixture itself.
April 2016
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Subclass 6.8 Reproductive/
developmental toxicity
NA
Subclass 6.8 Reproductive/
developmental toxicity (via
lactation)
NA
Subclass 6.9 Target organ
systemic toxicity2
6.9A
Subclass 9.1 Aquatic ecotoxicity
Staff’s
classification
Remarks
Mixture
rules1
Applicant’s
classification
Read across
Hazard Class/Subclass
Method of
classification
Mixture data
Mixture classification
ND
ND
6.9A
Paraquat
dichloride
9.1A
9.1A
Paraquat
dichloride
Subclass 9.2 Soil ecotoxicity
NA
ND
Subclass 9.3 Terrestrial
vertebrate ecotoxicity
9.3A
9.3A
Paraquat
dichloride
Subclass 9.4 Terrestrial
invertebrate ecotoxicity
9.4B
9.4B
Paraquat
dichloride
-: No information provided by the applicant
NA: Not Applicable --> For instance when testing is technically not possible: testing for a specific endpoint may be omitted, if it is
technically not possible to conduct the study as a consequence of the properties of the substance: e.g. very volatile, highly reactive or
unstable substances cannot be used, mixing of the substance with water may cause danger of fire or explosion or the radio-labelling of
the substance required in certain studies may not be possible.
ND: No Data or poor quality data (according to Klimisch criteria3) --> There is a lack of data for one or more components.
No: Data are available for the formulation or for all components and classification is not triggered.
3. Mammalian toxicology
3.1.
Studies submitted with the formulation and the active ingredient
technical concentrate
2
When appropriate include separate rows to address single as well as repeat dose target organ toxicity, and any of the relevant
routes (oral, dermal and/or inhalation).
3
Klimisch, H-J., Andrear, M., & U. Tillmann, 1997. A systematic approach for evaluating the quality of experimental toxicological
and ecotoxicological data. Reg. Toxicol. Pharmacol. 25, 1–5 (1997)
April 2016
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The applicant submitted a number of toxicity studies with the paraquat dichloride technical concentrate (44%
paraquat dichloride) and for a formulation coded “PARAQUAT 20% SL”, containing 200 g/L paraquat
dichloride. The amount of paraquat dichloride in PARAQUAT 20% SL is less than the amount of paraquat
dichloride in Para-Ken 250 Herbicide, which contains 250 g paraquat dichloride/L. The applicant provided a
bridging statement where reasons are presented to read-across the data from “PARAQUAT 20% SL” to the
Para-Ken 250 Herbicide. The applicant claims that the toxicological studies for Human health for the 20%
formulated product will be closely similar or the same for the 25%. This conclusion is stated to be based on
the results for the 44% Active and comparing them to the 20%. The applicant states that the results for a
number of the LD50 tests are stated to be nearly identical between the 20% and 44%, suggesting that the
results for the 20% formulation can be read across to the 25% formulation Para-Ken 250 Herbicide.
However, Staff note that while the results were similar in the majority of cases, in some tests there were
substantial differences. For example, in the acute dermal toxicity test with the 20% formulation mortality was
observed in all animals at 4000 mg/kg bw whereas with the technical concentrate (which contains a higher
concentration of paraquat dichloride) only 1/10 animals died at this dose. In addition, the composition of
“PARAQUAT 20% SL” was not provided so it was not possible to compare its composition with that of ParaKen 250 Herbicide. Therefore Staff have used mixture rules rather than the test data to classify Para-Ken
250 Herbicide.
4. Ecotoxicology
4.1.
Robust study summaries for the formulation
The applicant provided ecotox studies performed with a formulation coded “PARAQUAT 20% SL”, containing
200 g/L paraquat dichloride. The amount of paraquat dichloride in PARAQUAT 20% SL is less than the
amount of paraquat dichloride in Para-Ken 250 Herbicide, which contains 250 g paraquat dichloride/L. The
applicant provided a bridging statement where reasons are presented to read-across the data from
“PARAQUAT 20% SL” to the Para-Ken 250 Herbicide. The applicant claims that since the difference in the
amount of paraquat dichloride between the two formulations is 50 g/L the results may be used in the risk
assessment. Staff summarised the studies provided by the applicant and used the results when deemed
appropriate for the risk assessment. Classification of Para-Ken 250 Herbicide was carried out according to
mixture rules.
4.1.1. Aquatic toxicity
Fish acute toxicity (Freshwater species)
Type of study
Full test
Flag
Supplemental study, formulation is not Para-Ken 250 Herbicide
April 2016
10
Test Substance
PARAQUAT 20% SL (containing 210 g/L paraquat dichloride)
Species
Danio rerio (zebrafish)
Type of exposure
Semi-static for 96 hours, daily renewal
Endpoint
LC50
Value
141.42 mg/L, equivalent to 28.28 mg paraquat dichloride/L.
PM Bidinotto (2008) Acute toxicity of PARAQUAT 20% SL to fish Danio rerio.
Reference
BIOAGRI, Piracicaba, Brazil. Study No 5258.208.365.08
Klimisch Score
1
Amendments/Deviations
None
GLP
Yes
Test Guideline/s
OECD 203 (1992)
No/Group
7 fish per treatment
0, 50, 200, 400, 800 mg/L (nominal concentrations)
Dose Levels
Reference substance: potassium dichromate (0, 100, 180, 320 and 560 mg/L)
Analytical measurements
At the beginning and end of the tests using HPLC/UV
The acute toxicity of PARAQUAT 20% SL to the zebrafish Danio rerio was
determined in a semi-static test for 96 hours. The validity criteria were fulfilled.
Study Summary
The deviations between measured and nominal concentrations ranged between
2.53 and 14.02%, thus lower than 20%, therefore the endpoint is expressed as
nominal concentration. The LC50 was 141.42 mg/L.
Conclusion
The LC50 was 141.42 mg/L, equivalent to 28.28 mg paraquat dichloride/L.
Fish chronic toxicity (Freshwater species)
No study provided.
Invertebrate acute toxicity (Freshwater species)
Type of study
Full test
Flag
Supplemental study, formulation is not Para-Ken 250 Herbicide
Test Substance
PARAQUAT 20% SL (containing 210 g/L paraquat dichloride)
Species
Daphnia magna
Type of exposure
Semi-static for 48 hours, renewal after 24h
Endpoint
EC50
Value
17.43 mg/L
April 2016
11
JN Sesso (2008) Acute toxicity of PARAQUAT 20% SL to Daphnia magna.
Reference
BIOAGRI, Piracicaba, Brazil. Study No 5258.206.370.08.
Klimisch Score
1
Amendments/Deviations
None
GLP
Yes
Test Guideline/s
OECD 202 (2004)
No/Group
4 replicates of 5 Daphnids per treatment
0, 6.5, 13, 25, 50, 100 mg/L (nominal concentrations)
Dose Levels
Reference substance: potassium dichromate (0, 0.32, 0.56, 1.0, 1.8 and 2.4
mg/L)
Analytical measurements
At the beginning and end of the tests using HPLC/UV
The acute toxicity of PARAQUAT 20% SL to Daphnia magna was determined in
a semi-static test for 48 hours. Deviations from nominal concentrations ranged
Study Summary
from 3.64 to 15.85%, therefore all effect levels were based on nominal
concentrations. The validity criteria were fulfilled.
The 48-hour EC50 was 17.43 mg/L.
Conclusion
The EC50 was 17.43 mg/L, equivalent to 3.5 mg paraquat dichloride/L.
Invertebrate chronic toxicity (Freshwater species)
No study provided.
Algae acute toxicity (Freshwater species)
Type of study
Full test
Flag
Supplemental study, formulation is not Para-Ken 250 Herbicide
Test Substance
PARAQUAT 20% SL (containing 210 g/L paraquat dichloride)
Species
Pseudokirchneriella subcapitata
Type of exposure
Static for 72 hours
Endpoint
ErC50 and EyC50
Value
ErC50 = 2.41 mg/L; EyC50 = 0.88 mg/L
PM Bidinotto (2008) Toxicity of PARAQUAT 20% SL to alga
Reference
Pseudokirchneriella subcapitata. BIOAGRI, Piracicaba, Brazil. Study No
5258.202.359.08
Klimisch Score
April 2016
1
12
Amendments/Deviations
None
GLP
Yes
Test Guideline/s
OECD 201 (2006)
No/Group
104 cells/mL
0, 0.1, 0.32, 1, 3.2, 10 mg/L(nominal concentrations)
Dose Levels
Reference substance: potassium dichromate (0, 0.18, 0.32, 0.56, 1.0 and 1.8
mg/L)
Analytical measurements
At the beginning and end of the tests using HPLC/UV
The aim of this study was to determine the effects of PARAQUAT 20% SL on
the growth rate and yield of the green alga over a period of 72 hours.
Deviations from nominal concentrations ranged from 0.4 to 11.75%, therefore
Study Summary
all effect levels were based on nominal concentrations. The study met the
validity criteria of the test guideline.
The 72-hour EyC50 was 0.88 mg/L (CI: 0.74 – 1.03 mg/L) and the 72-hour ErC50
was 2.41 mg/L (CI: 2.08 -2.80 mg/L).
The EyC50 was 0.88 mg formulation/L and the ErC50 was 2.41 mg
Conclusion
formulation/L.
General conclusion about aquatic toxicity classification
Para-Ken 250 Herbicide is classified as 9.1A, according to mixture rules.
4.1.2. Soil toxicity
Soil macro-invertebrates
Type of study
Limit test
Flag
Supplemental study, formulation is not Para-Ken 250 Herbicide
Test Substance
PARAQUAT 20% SL (containing 210 g/L paraquat dichloride)
Species
Eisenia foetida
Type of exposure
Spiked soil for 14 days
Endpoint
LC50
Value
>1000 mg/kg soil
RA Franco (2008) Acute toxicity of PARAQUAT 20% SL to earthworm Eisenia
Reference
foetida. BIOAGRI, Piracicaba, Brazil. Study No 5258.203.381.08
Klimisch Score
April 2016
1
13
Amendments/Deviations
None
GLP
Yes
Test Guideline/s
OECD 207 (1984)
No/Group
4 replicates of 10 earthworms per treatment
0, 1000 mg/kg soil
Dose Levels
Reference: chloroacetamide
Analytical measurements
At the beginning and end of the tests using HPLC/UV
The aim of this study was to determine the effects of PARAQUAT 20% SL on
the survival of the earthworm Eisenia foetida. The study met the validity criteria
Study Summary
of the test guideline.
The 14-day LC50 was higher than 1000 mg formulation/kg bw.
Conclusion
The 14-day LC50 was higher than 1000 mg formulation/kg bw.
Non-target terrestrial plants
No study provided.
Nitrogen transformation test
Type of study
Full test
Flag
Supplemental study, formulation is not Para-Ken 250 Herbicide
Test Substance
PARAQUAT 20% SL (containing 210 g/L paraquat dichloride)
Species
Soil microflora
Type of exposure
Spiked soil for 28 days
Endpoint
Nitrogen transformation
Value
No effects of PARAQUAT 20% SL at 3 kg paraquat dichloride per hectare.
VCB Cardinalli (2008) Effects of PARAQUAT 20% SL to soil microoganisms:
Reference
Nitrogen transformation test. BIOAGRI, Piracicaba, Brazil. Study No
5258.218.328.08
Klimisch Score
1
Amendments/Deviations
None
GLP
Yes
Test Guideline/s
OECD 216 (2000)
No/Group
3 replicates per treatment
0, 0.6 kg paraquat dichloride/ha (maximum used rate), 3 kg paraquat
Dose Levels
dichloride/ha (5*MUR)
April 2016
14
Analytical measurements
At the beginning of the test in the stock solution using HPLC/UV
The aim of this study was to determine the effects of PARAQUAT 20% SL on
soil microorganisms through a nitrogen transformation test using two different
Brazilian soils, a Latosoil (LVdf) and an Argisoil (PVAe) as test systems. The
Study Summary
study met the validity criteria of the test guideline. Two concentrations were
tested: 0.6 kg a.i./ha and 3 kg a.i./ha. The deviation at the end of the 28 days of
exposure between control and treated soils were below the 25% threshold.
Effects of PARAQUAT 20% SL were below 25% at 3 kg paraquat dichloride
Conclusion
per hectare.
Carbon transformation test
Type of study
Full test
Flag
Supplemental study, formulation is not Para-Ken 250 Herbicide
Test Substance
PARAQUAT 20% SL (containing 210 g/L paraquat dichloride)
Species
Soil microflora
Type of exposure
Spiked soil for 28 days
Endpoint
Carbon transformation
Value
No effects of PARAQUAT 20% SL at 3 kg paraquat dichloride per hectare.
VCB Cardinalli (2008) Effects of PARAQUAT 20% SL to soil microorganisms:
Reference
Carbon transformation test. BIOAGRI, Piracicaba, Brazil. Study No
5258.201.468.08
Klimisch Score
1
Amendments/Deviations
None
GLP
Yes
Test Guideline/s
OECD 217 (2000)
No/Group
3 replicates per treatment
0, 0.6 kg paraquat dichloride/ha (maximum used rate), 3 kg paraquat
Dose Levels
dichloride/ha (5*MUR)
Analytical measurements
At the beginning of the test in the stock solution using HPLC/UV
The aim of this study was to determine the effects of PARAQUAT 20% SL on
soil microorganisms through a carbon transformation test using two different
Study Summary
Brazilian soils, a Latosoil (LVdf) and an Argisoil (PVAe) as test systems. The
study met the validity criteria of the test guideline. Two concentrations were
April 2016
15
tested: 0.6 kg a.i./ha and 3 kg a.i./ha. The deviation at the end of the 28 days of
exposure between control and treated soils were below the 25% threshold.
Effects of PARAQUAT 20% SL were below 25% at 3 kg paraquat dichloride
Conclusion
per hectare.
General conclusion about soil toxicity classification
Para-Ken 250 Herbicide does not trigger a classification for soil toxicity.
4.1.3. Terrestrial vertebrate toxicity
Acute oral toxicity
Type of study
Full test
Flag
Supplemental study, formulation is not Para-Ken 250 Herbicide
Test Substance
PARAQUAT 20% SL (containing 210 g/L paraquat dichloride)
Species
Coturnix coturnix japonica (Japanese quail)
Type of exposure
Acute oral
Endpoint
LD50
Value
775.92 mg/kg bw
RA Franco (2008) Avian acute toxicity test of PARAQUAT 20% SL in Japanese
Reference
quails. BIOAGRI, Brazil. Study No 5258.302.410.08.
Klimisch Score
2
Amendments/Deviations
None that have impacted the results
GLP
No
Test Guideline/s
OPPTS 850.2100 (1996)
No/Group
10 (5 males and 5 females) per treatment
Dose Levels
0 (control), 257.2, 429.6, 717.4, 1198 and 2000 mg formulation/kg bw
Analytical measurements
Not required
PARAQUAT 20% SL was tested for acute oral toxicity in birds using the
Japanese quail. Twenty-one dosed quails (42%) died in the study. Compoundrelated deaths were registered on 717.4 (1 or 10%), 1198 (10 or 100%) and
Study Summary
2000 (10 or 100%) mg/kg bw. Dose-related clinical signs (apathy, ataxia, ruffled
feathers, dyspnea, sialorrhea and decubitus) were acute neurological and
respiratory signs observed on 717.4, 1198 and 2000 mg/kg bw. No animal from
control groups, 257.2 and 429.6 mg/kg bw presented any clinical sign during
April 2016
16
the 14-day observation period. The validity criteria were met. The combined
(males and females) LD50 of the test substance PARAQUAT 20% SL was
775.92 mg/kg bw.
Conclusion
The LD50 was 775.92 mg formulation/kg bw.
General conclusion about toxicity to terrestrial vertebrate classification
Para-Ken 250 Herbicide is classified as 9.3A, according to mixture rules.
4.1.4. Ecotoxicity to terrestrial invertebrates
Bees – Laboratory studies
Type of study
Full test
Flag
Supplemental study, formulation is not Para-Ken 250 Herbicide
Test Substance
PARAQUAT 20% SL (containing 210 g/L paraquat dichloride)
Species
Apis mellifera
Type of exposure
48 hours, contact
Endpoint
LD50
Value
41.23 µg/bee (equivalent to 8.25 µg a.i./bee)
RA Franco (2008) Acute contact toxicity test of PARAQUAT 20% SL to
Reference
honeybee Apis mellifera (africanized). BIOAGRI, Brazil. Study No
5258.204.385.08.
Klimisch Score
1
Amendments/Deviations
None that have impacted the results
GLP
Yes
Test Guideline/s
OECD 214 (1998)
No/Group
3 replicates with 10 bees per treatment
0, 7.8125, 15.625, 31.25, 62.25 and 125 µg/bee (nominal concentrations),
Dose Levels
equivalent to 1.5625, 3.125, 6.25, 12.5 and 25 µg a.i./bee
Reference item: dimethoate
Analytical measurements
Not required
The acute contact toxicity of PARAQUAT 20% SL to the honeybee was tested.
Study Summary
The validity criteria were met. The LD50 (48 hours) was 41.23 µg a.i./bee.
Conclusion
April 2016
LD50 = 41.23 µg/bee (equivalent to 8.25 µg a.i./bee)
17
General conclusion about toxicity to terrestrial invertebrate classification
Para-Ken 250 Herbicide is classified as 9.4B, according to mixture rules.
5. Human health risk assessment
5.1.1.
Para-Ken 250 Herbicide contains paraquat dichloride and is proposed to be used in a higher
application rate than other approved substances containing this active ingredient. Therefore, a
quantitative human health risk assessment was undertaken.
Quantitative worker (operator) risk assessment
Critical endpoint definition
Using an existing AOEL for paraquat
Available
international
AOELs
Key
systemic
effect
Pulmonary
lesions,
clinical
chemistry,
and urine
analysis
EU (2003)
NOAEL
mg/kg
bw/Day
Uncertainty
factors
AOEL
mg/kg
bw/Day
Staff’s
modifications
Remarks
None
Corrected for
10% oral
absorption
AOEL
short
term:
0.0005
0.45
100
AOEL
long
term:
0.0004
(90 day
and 1 year
dog
studies)
Other inputs for human worker (operator) and re-entry exposure modelling4
Active
Physical
form
Concentration
of each active
(g/L)
Maximum
application rate
(for each active, for
Dermal absorption (%)
each method of
Concentrate
AOEL
Spray
application)
mg/kg
bw/day
g a.i./ha
Paraqu
at ion
Liquid
1500
6
30
0.0005
The EPA’s operator exposure assessment is based on a modification of the approach used by European regulators. Full details of the
methodology can be provided on request.
4
April 2016
18
Comments on inputs for human worker (operator) exposure modelling input parameters:
Dermal absorption
Dermal absorption data for paraquat in the formulation Para-Ken 250 were not provided. In the absence of
specific data Staff consider it is appropriate to use default values for dermal absorption, as recommended in
EFSA guidance on Guidance on Dermal Absorption (2012 5) and OECD Guidance Notes on Dermal
Absorption (20116). For pesticides, Staff have agreed to adopt less conservative default values than those
proposed in the EFSA and OECD guidance, using default values proposed by Aggarwal et al (2015 7), which
are based on a review of a robust data set of 295 in vitro human dermal absorption studies with over 150
agrochemical active ingredients. These default values are 2% for solid concentrates, 6% for liquid
concentrates and 30% for spray dilutions.
Staff note that the oral absorption of paraquat is low (10% for paraquat). Staff considered whether it may be
possible to use this information to refine the dermal absorption values however no oral absorption,
distribution, metabolism and excretion (ADME) studies are available with the Para-Ken 250 Herbicide
formulation and the influence of the co-formulants in this formulation on dermal absorption is unknown.
Therefore staff do not consider it appropriate to use oral absorption as a surrogate dermal absorption value.
Staff also note that assessments of the EU and the US EPA have noted that dermal absorption of paraquat
may be as low as 0.5%, however these conclusions predate the introduction of the OECD and EFSA
guidance on dermal absorption which provides criteria for deciding when it is appropriate to read across data
to a specific formulation. In this case information is not available as to the formulations or vehicles used to
perform the dermal absorption studies with paraquat and how these compare to the Para-Ken 250 Herbicide
formulation.
In the absence of more information Staff consider it is appropriate to use the default dermal absorption
values in the present assessment, however it is acknowledged that these values may result in an
overestimate of exposure.
Work rates
Para-Ken 250 Herbicide is intended to be used the control of weeds in Lucerne, Clover seed crops, Forestry,
Industrial site, Streets and for Barley grass control by high volume broadcast and by hand gun. The default
work rate for boom spraying for cereals, legume vegetables, bare soil and grasslands in the EPA exposure
assessment model is 50 ha per day. Staff have assumed that this work rate is appropriate for the proposed
uses of Para-Ken 250 Herbicide.
The default work rate for knapsack/hand gun spraying is 1 ha per day.
5
EFSA 2012 Guidance on dermal absorption. EFSA Panel on Plant Protection Products and their Residues. EFSA Journal 2012:
10(4):2665
http://ec.europa.eu/food/plant/pesticides/guidance_documents/docs/efsa_guidance_document_dermal_absorption_18042012.pdf
Accessed 05/02/2016
6
OECD 2011 OECD Guidance notes on dermal absorption. Series on Testing and Assessment, No. 156. ENV/JM/MONO(2011)36
http://www.oecd.org/chemicalsafety/testing/48532204.pdf Accessed 05/02/2016
7
Aggarwal et al. 2015 Assessment of an extended dataset of in vitro human dermal absorption studies on pesticides to determine
default values, opportunities for read-across and influence of dilution on absorption. Regul Toxicol Pharmacol 72: 58-70.
http://www.sciencedirect.com/science/article/pii/S0273230015000458
April 2016
19
Output of human worker (operator) mixing, loading and application exposure modelling
Estimated operator
exposure (mg/kg bw/day)
Risk Quotient
No PPE8 during mixing, loading and application
0.8117
1623.43
Gloves only during mixing and loading
0.6729
1345.71
Gloves only during application
0.7018
1403.57
Full PPE during mixing, loading and application
(excluding respirator)
0.0560
112.07
Full PPE during mixing, loading and application
(including FP1, P1 and similar respirator achieving 75 %
inhalation exposure reduction)
0.0546
109.11
Full PPE during mixing, loading and application
(including FP2, P2 and similar respirator achieving 90 %
inhalation exposure reduction)
0.0543
108.60
No PPE during mixing, loading and application
0.5308
1061.57
Gloves only during mixing and loading
0.2936
587.14
Gloves only during application
0.4695
938.91
Full PPE during mixing, loading and application
(excluding respirator)
0.0503
100.50
Full PPE during mixing, loading and application
(including FP1, P1 and similar respirator achieving 75 %
inhalation exposure reduction)
0.044316
88.63
Full PPE during mixing, loading and application
(including FP2, P2 and similar respirator achieving 90 %
inhalation exposure reduction)
0.043191
86.38
Exposure Scenario
Boom
Backpack - High Level Target
Outcomes of the worker (operator) exposure assessment
Predicted exposures of workers (operators) during mixing, loading and application of Para-Ken 250
Herbicide are greater than the AOEL for paraquat for both boom and knapsack spraying, even with the use
of full PPE including a respirator9.
Re-entry exposure assessment
8 Full”
PPE includes: gloves, hood/visor, coveralls, and heavy boots during application. The model only provides for use
of gloves at mixing loading.
9
Gloves, hood/visor, coveralls, and heavy boots with a respirator
April 2016
20
Para-Ken 250 Herbicide is intended to be used primarily before sowing or transplanting, or before crop
emergence. Therefore staff anticipate that re-entry worker exposure to Para-Ken 250 Herbicide is likely to be
minimal and no quantitative re-entry worker exposure assessment is required.
Quantitative bystander risk assessment10
The AOEL derived for operator and re-entry worker assessment above is also used for the bystander
assessment calculations.
Output of human bystander exposure modelling11
Exposure Scenario
Estimated exposure of 15
kg toddler exposed
through contact to
surfaces 8 m from an
application area
Risk Quotient
Buffer zone
needed to
reduce toddler
exposure to
the AOEL
(µg/kg bw/day)
Boom
High boom, fine droplets
10.54
21.0817
136
High boom, coarse droplets
1.67
3.3446
30
Low boom, fine droplets
3.56
7.1143
70
Low boom, coarse droplets
0.85
1.6924
16
Staff note that the intended use pattern for Para-Ken 250 Herbicide includes Street verges. It is possible that
in some cases children may play on such areas. Therefore Staff have also assessed the potential
recreational exposure for children. This uses the same approach as the bystander exposure assessment;
apart from the fact that the area of contact is 0 m from the application area.
Output of recreational exposure modelling
Estimated exposure of 15
kg toddler exposed
through contact to
surfaces 0 m from an
application area
10
Risk Quotient
The Staff considers that the main potential source of exposure to the general public for substances of this type (other than via food
residues which will be considered as part of the registration of this substance under the Agricultural Compounds and Veterinary
Medicines (ACVM) Act 1997) is via spray drift. In terms of bystander exposure, toddlers are regarded as the most sensitive subpopulation and are regarded as having the greatest exposures. For these reasons the risk of bystander exposure is assessed in this
sub-population. EPA has agreed that the AOEL used for operator and re-entry worker exposure assessment should be used for the
bystander assessment, as the use of an oral chronic reference dose (CRfD) is usually likely to be over precautionary.
11 The EPA’s bystander exposure assessment is based on a modification of the approaches used by European regulators and the US
EPA. Full details of the methodology can be found in Appendix X.. Spray drift deposition from ground based application is estimated
using the AgDisp model. Spray drift deposition from aerial application is estimated using the AGDISP model along with appropriate New
Zealand input parameters.
April 2016
21
(µg/kg bw/day)
108
216
Outcomes of the bystander exposure assessment
Predicted exposures of bystanders are greater than the AOEL for paraquat. If spraying of Para-Ken 250
Herbicide were limited to use of coarse droplets, minimum buffer zones of 16 or 30 metres from sensitive
areas would be required for low boom or high boom application, respectively, in order to reduce exposures to
the AOEL.
Exposures for children playing directly on a treated area are also substantially higher than the AOEL.
5.2. Summary and conclusions of the human health risk assessment
Predicted exposures of operators during mixing, loading and application of Para-Ken 250 Herbicide are
greater than the AOEL for paraquat, even with the use of full PPE including a respirator.
Based on the use pattern re-entry worker exposure to Para-Ken 250 Herbicide is likely to be minimal and
therefore no quantitative re-entry worker exposure assessment has been performed.
Predicted exposures of a bystander 8 metres away from the edge of an application area are greater than the
acceptable levels for both active ingredients. If spraying of Para-Ken 250 Herbicide were limited to use of
coarse droplets, minimum buffer zones of 16 or 30 metres from sensitive areas would be required for low
boom or high boom application, respectively, in order to reduce exposures to the AOEL.
Predicted exposures for children playing directly on a treated area are also substantially higher than the
AOEL.
The risk assessment includes a number of default assumptions which leads to conservatism in the risk
assessment. Information that could potentially be used to refine the risk assessment includes:

Dermal absorption data for the active ingredients in the Para-Ken 250 formulation

Information on the expected work rates per day for each use scenario

Operator exposure studies

Confirmation that the application rate relates to the paraquat ion

Information on the relevance of the recreational exposure scenario included in the present risk
assessment
However, with regard to dermal absorption, Staff note that even if the low value of 0.5% absorption proposed
by the EU in 2002 were confirmed as being suitable for use in the risk assessment, this would lead to
predicted exposures greater than the AOEL for operators mixing, loading and applying Para-Ken 250
Herbicide by boom and knapsack application methods (RQs of 4 and 6, respectively).
April 2016
22
6. Environmental risk assessment
Para-Ken 250 Herbicide contains paraquat dichloride and is proposed to be used in a higher application rate
than other approved substances containing paraquat dichloride. Therefore, a quantitative risk assessment
for the environment was undertaken.
6.1. Robust studies with the active ingredient
The information on the environmental fate and behaviour and ecotoxicological data of paraquat dichloride
are depicted in Table 1 and Table 2.
April 2016
Table 3: Summary of environmental fate data on paraquat dichloride
Test
Paraquat dichloride
Hydrolytically stable at pH 5, 7 and 9 after 30
Hydrolysis
days at 25 and 40 °C.
Rapid biodegradation in
Not rapidly biodegradable.
water
Photolytically stable at environmentally
Aqueous photolysis
relevant wavelengths.
Aerobic degradation in water
(water/sediment)
Anaerobic degradation
The log Kow for paraquat dichloride is -4.5 at
Bioaccumulation
20 °C indicating that bioaccumulation is
unlikely.
Paraquat is expected to be almost immobile
Aerobic degradation in soil
in soil. The estimated average field half-life of
(laboratory)
paraquat in soil is 1000 days.
Aerobic degradation in soil
No half-life calculated, estimates indicate
(field)
more than 10 years.
Soil photolysis
-
Adsorption/desorption
Koc = 1000000
(Koc values)
Volatilisation
-
No data provided
Not relevant, due to low vapour pressure.
24
Table 4: Summary of ecotoxicological data on paraquat dichloride – Values in bold are used for the risk
assessment.
Test
Paraquat dichloride
Reference
Paraquat 20% SL
Acute / fish
LC50 = 10.85 mg/L
(Barbus sharpeyi)
EPA internal
database
LC50 = 141.42 mg/L,
equivalent to 28.28
mg a.i./L)
Acute / aquatic
invertebrates
EC50 = 1.2 mg/L
(Daphnia magna)
EPA internal
database
EC50 = 17.43 mg/L,
equivalent to 3.49
mg a.i./L
ErC50 = 2.41 mg/L,
equivalent to 0.48
mg a.i/L
EC50 = 0.32 mg/L
(Selenastrum
capricornutum)
EPA internal
database
EC50 = 0.00055 mg/L
(Naviculla peliculosa)
EPA internal
database
-
EC50 = 0.098 mg/L
EPA internal
database
-
Chronic / fish
-
-
-
Chronic / Aquatic
invertebrates
NOEC = 0.12 mg/L
SANCO, 2003
-
Chronic toxicity sediment
dwelling organism Chironomus
NOEC = 100 mg/kg
(sediment);
SANCO, 2003
-
Algae
Algae - diatom
Aquatic plant
(Lemna gibba)
(Pseudokirchneriella
subcapitata)
(Daphnia magna)
NOEC = 0.367 mg/L
(water phase only)
Acute / Earthworm
LC50 > 1380 mg/kg
soil
EPA internal
database
LC50 > 210 mg
a.i./kg soil
Chronic / Earthworm
-
-
-
SANCO, 2003
No adverse effects
on carbon and
nitrogen
transformations
after application up
to 3 kg a.i./ha.
Soil microorganisms
No adverse effects
were observed after
application up to 720
kg ai/ha in one year.
EC25 = 0.95 kg/ha
(seedling emergence,
cocklebur)
Non target plants
EC25 = 0.015 kg/ha
(vegetative vigour,
cocklebur)
April 2016
EPA internal
database
25
NOEC = 0.004 kg/ha
(vegetative vigour,
cocklebur)
LD50 = 35 mg/kg bw
Acute / bird
LD50 = 176 mg/kg bw
Reproduction bird
NOEC = 2.8 mg/kg
bw/d
LD50 (contact) = 9.26
µg/bee
Acute / bees
Non target arthropods
-
SANCO, 2003
EPA internal
database
LD50 = 775.92
mg/kg bw,
equivalent to 155.2
mg a.i./kg bw
USEPA, 1997
SANCO, 2003
EPA internal
database
LD50 (oral) = 9.06
µg/bee (120-hr study)
SANCO, 2003
-
-
LD50 (contact) =
41.23 µg/bee
(equivalent to 8.25
µg a.i./bee)
-
No data provided
6.2. Risk assessment Methodology
Methods used to assess environmental exposure and risk differ between environmental compartments
(Table 5).
Table 5 Reference documents for environmental exposure and risk assessments
Aquatic organisms
Environmental exposure
Risk assessment
(GEN)eric (E)stimated
(E)nvironmental (C)oncentration
Model Version 2.0 – 01 August
2002
Overview of the Ecological Risk Assessment
Process in the Office of Pesticide Programs, U.S.
Environmental Protection Agency. Endangered
and threatened Species Effects Determinations –
23 January 2004
AgDrift and EPA Software12
12
The Staff used two different models for assessing the EEC and associated risks:
Generic Estimated Environmental Concentration Model v2 (GENEEC2) surface water exposure model (USEPA,
2001) estimates the concentration of substance in surface water which may arise as a result of surface runoff and
spraydrift.
 To examine how buffer zones would reduce the active ingredient concentrations in receiving waters, the Staff used
the AgDRIFT® model (developed under a cooperative Research and Development Agreement, CRADA, between the
EPA, USDA, US Forest Service, and SDTF). AgDRIFT® incorporates a proposed overall method for evaluating offsite deposition of aerial, orchard or ground applied pesticides, and acts as a tool for evaluating the potential of buffer
zones to protect sensitive aquatic and terrestrial habitats from undesired exposures. Calculations are made assuming
the receiving water is a 30 cm deep pond. The model is used to estimate the buffer zone that would reduce exposure
through spray drift to such a concentration that an acute risk quotient of 0.1 cannot be calculated. It is noted that

April 2016
26
Guidance on information
requirements and
Sediment
organisms
chemical safety assessment,
Chapter R.16: Environmental
Exposure Estimation, Version: 2 May 2010
Guidance on information requirements and
chemical safety assessment, Chapter R.10:
Characterisation of dose [concentration]-response
for environment – May 2008
Soil organisms,
invertebrates
(macroinvertebrates)
Soil persistence models and EU
registration. The final report of the
work of the Soil Modelling Work
group of FOCUS (FOrum for the
Co-ordination of pesticide fate
models and their USe) – 29
February 1997
Bees
Guidance for assessing pesticide risks to bees. US EPA, Health Canada Pest
Management Regulatory Agency, California Department of Pesticide Regulation, 19 June
2014
Terrestrial
organisms,
invertebrates (nontarget arthropods)
Guidance document on regulatory testing and risk assessment procedures for plant
protection products with non-target arthropods. From ESCORT 2 Workshop – 21/23
March 2000
SANCO/10329/2002 rev 2 final. Guidance
Document on terrestrial ecotoxicology under
Council Directive 91/414/EEC- 17 October 2002
Guidance of EFSA. Risk assessment to birds and mammals – 17 December 2009.
Terrestrial
vertebrates (birds)
Secondary
poisoning and
biomagnification
EFSA calculator tool - 200913
SANCO/4145/2000 final. Guidance Document on risk assessment for birds and mammals
under Council Directive 91/414/EEC- 25 September 2002
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, Directive 98/8/EC of
the European Parliament and of the
Council concerning the placing of
biocidal products on the market –
Part II - 2003
Guidance of EFSA. Risk assessment to birds and
mammals – 17 December 2009
EFSA calculator tool - 2009
SANCO/4145/2000 final. Guidance Document on
risk assessment for birds and mammals under
Council Directive 91/414/EEC- 25 September
2002
6.3. Consideration of threatened native species
unlike GENEEC2, AgDRIFT® model only considers transport by spray drift, input through runoff, volatilisation, etc. will
pose additional risks.
13
www.efsa.europa.eu/en/efsajournal/pub/1438.htm
April 2016
27
No studies are requested to be conducted on native New Zealand species; the risk assessment is based on
studies performed on standard surrogate species from Europe or North America. Uncertainty factors
included in the risk assessment process encompass the possible susceptibility variations between the
surrogate species and the native New Zealand species. However, these factors are designed to protect
populations not individual organisms. EPA staff acknowledge that these factors may not be protective
enough for threatened species for which the survival of the population could depend on the survival of each
and every individual.
Therefore, the US EPA approach for risk assessment of endangered species has been implemented.
Additional uncertainty factors are included, depending on the type of organisms. US EPA consider higher
factors when organisms cannot escape the contaminated area (for aquatic organisms for instance) than for
birds.
US EPA has not defined any additional factor for soil organisms except for plants, so EPA staff applied the
same approach as for aquatic environment, considering that soil invertebrates won’t be able to escape from
the contaminated area.
For the purpose of this risk assessment, the threatened species are those included in the following
categories of the New Zealand Threat Classification System: threatened (Nationally critical, Nationally
endangered, Nationally vulnerable) and at risk (declining, recovering, relict, and naturally uncommon).
6.4. Aquatic risk assessment
For Class 9 substances, irrespective of the intrinsic hazard classification, the ecological risk can be assessed
for a substance by calculating a Risk Quotient (RQ) based on an estimated exposure concentration. Such
calculations incorporate toxicity values, exposure scenarios (including spray drift, leaching and run-off,
application rates and frequencies), and the half-lives of the component(s) in water. For the aquatic
environment, the calculations provide an Estimated Environmental Concentration (EEC) which, when divided
by the L(E)C50 or a NOEC, gives a RQ acute or chronic.
𝐴𝑐𝑢𝑡𝑒 𝑅𝑄 =
𝐸𝐸𝐶𝑠ℎ𝑜𝑟𝑡−𝑡𝑒𝑟𝑚
𝐿(𝐸)𝐶50
𝐶ℎ𝑟𝑜𝑛𝑖𝑐 𝑅𝑄 =
𝐸𝐸𝐶𝑙𝑜𝑛𝑔−𝑡𝑒𝑟𝑚
𝑁𝑂𝐸𝐶
If the RQ exceeds a predefined level of concern, this suggests that it may be appropriate to refine the
assessment or apply the approved handler control and/or other controls to ensure that appropriate matters
are taken into account to minimize off-site movement of the substance. Conversely, if a worst-case scenario
is used, and the level of concern is not exceeded, then in terms of the environment, there is a presumption of
April 2016
28
low risk which is able to be adequately managed by such things as label statements (warnings, disposal).
The approved handler control can then be removed on a selective basis.
Levels Of Concern (LOC) developed by the USEPA (Urban and Cook, 1986) and adopted by EPA determine
whether a substance poses an environmental risk (Table 6).
Table 6 Levels of concern as adopted by EPA New Zealand
Endpoint
LOC
Presumption
Aquatic (fish, invertebrates, algae, aquatic plants)
Acute RQ
≥ 0.5
High acute risk
Acute RQ
0.1 - 0.5
Risk can be mitigated through restricted use
Acute RQ
< 0.1
Low risk
Chronic RQ
≥1
High chronic risk
Aquatic threatened species
Acute RQ
≥ 0.05
High acute risk
Chronic RQ
≥ 0.1
High chronic risk
RQ ≥ 1 calculated on the
basis of EC25 or TER < 5
calculated on the basis of
EC50
High acute risk
Plants (terrestrial)
Acute RQ /TER
Threatened plants species (terrestrial)
Acute RQ
≥ 1 calculated on the basis of
the NOEC or EC05
High acute risk
6.4.1. GENEEC2 modelling
Calculation of expected environmental concentrations
The parameters used in GENEEC2 modelling are listed in Table 7.
Table 7 Input parameters for GENEEC2 analysis
April 2016
29
Non-crop
Non
selective
Clover seed
fence lines,
weed
crops
streets,
control
industrial
(barley
sites
grass)
400
Application frequency
1-2
Application interval
(days)
28 days
Koc*
15 473
Aerobic soil DT50
(days)
1000
Pesticide wetted in?
No
HV broadcast
Methods of application
‘No spray’ zone
No
Water solubility (ppm)
620 000
Hydrolysis (DT50 in
days)
Stable
Aerobic aquatic DT50
whole system (days)**
2000
Aqueous photolysis
DT50 (days)
Stable
1500
1000
600
600 - 1500
1-4
1-2
1-2
1-4
HV broadcast,
knapsack,
handgun
HV
broadcast
HV
broadcast
Handgun
0.03223
0.01091
0.00652
Low dose =
0.01284
0.00437
*Lowest value of a non sand soil
** Twice the value of the DT50 soil according to the GENEEC2 recommendations
Output from the GENEEC2 model for paraquat dichloride
April 2016
Lucerne
situations:
Application rate (g
a.i./ha)
Highest concentration
Peak EEC (mg/L)
Forestry
High dose =
0.03223
30
RUN No.
1 FOR Paraquat dichlor ON
Clover
* INPUT VALUES *
-------------------------------------------------------------------RATE (#/AC)
No.APPS &
SOIL SOLUBIL
APPL TYPE NO-SPRAY INCORP
ONE(MULT)
INTERVAL
Koc
(PPM )
(%DRIFT)
(FT)
(IN)
-------------------------------------------------------------------0.356( 0.705)
2 28
15473.0*******
GRHIFI( 6.6)
0.0
0.0
FIELD AND STANDARD POND HALFLIFE VALUES (DAYS)
-------------------------------------------------------------------METABOLIC DAYS UNTIL HYDROLYSIS
PHOTOLYSIS
METABOLIC COMBINED
(FIELD)
RAIN/RUNOFF
(POND)
(POND-EFF)
(POND)
(POND)
-------------------------------------------------------------------1000.00
2
0.00
0.000.00 ******
2000.00
GENERIC EECs (IN MICROGRAMS/LITER (PPB))
Version 2.0 Aug 1, 2001
-------------------------------------------------------------------PEAK
MAX 4 DAY
MAX 21 DAY
MAX 60 DAY
MAX 90 DAY
GEEC
AVG GEEC
AVG GEEC
AVG GEEC
AVG GEEC
-------------------------------------------------------------------4.37
4.17
3.19
1.92
1.43
RUN No.
2 FOR Paraquat dichlor ON
Non crop s
* INPUT VALUES *
-------------------------------------------------------------------RATE (#/AC)
No.APPS &
SOIL SOLUBIL
APPL TYPE NO-SPRAY INCORP
ONE(MULT)
INTERVAL
Koc
(PPM )
(%DRIFT)
(FT)
(IN)
-------------------------------------------------------------------1.335( 5.190)
4 28
15473.0*******
GRHIFI( 6.6)
0.0
0.0
FIELD AND STANDARD POND HALFLIFE VALUES (DAYS)
-------------------------------------------------------------------METABOLIC DAYS UNTIL HYDROLYSIS
PHOTOLYSIS
METABOLIC COMBINED
(FIELD)
RAIN/RUNOFF
(POND)
(POND-EFF)
(POND)
(POND)
-------------------------------------------------------------------1000.00
2
N/A
0.000.00
******
2000.00
GENERIC EECs (IN MICROGRAMS/LITER (PPB))
Version 2.0 Aug 1, 2001
-------------------------------------------------------------------PEAK
MAX 4 DAY
MAX 21 DAY
MAX 60 DAY
MAX 90 DAY
GEEC
AVG GEEC
AVG GEEC
AVG GEEC
AVG GEEC
-------------------------------------------------------------------32.23
30.82
23.55
14.19
10.54
RUN No.
3 FOR Paraquat dichlor ON
Forestry
* INPUT VALUES *
-------------------------------------------------------------------RATE (#/AC)
No.APPS &
SOIL SOLUBIL
APPL TYPE NO-SPRAY INCORP
ONE(MULT)
INTERVAL
Koc
(PPM )
(%DRIFT)
(FT)
(IN)
-------------------------------------------------------------------0.890( 1.764)
2 28
15473.0*******
GRHIFI( 6.6)
0.0
0.0
April 2016
31
FIELD AND STANDARD POND HALFLIFE VALUES (DAYS)
-------------------------------------------------------------------METABOLIC DAYS UNTIL HYDROLYSIS
PHOTOLYSIS
METABOLIC COMBINED
(FIELD)
RAIN/RUNOFF
(POND)
(POND-EFF)
(POND)
(POND)
-------------------------------------------------------------------1000.00
2
N/A
0.000.00
******
2000.00
GENERIC EECs (IN MICROGRAMS/LITER (PPB))
Version 2.0 Aug 1, 2001
-------------------------------------------------------------------PEAK
MAX 4 DAY
MAX 21 DAY
MAX 60 DAY
MAX 90 DAY
GEEC
AVG GEEC
AVG GEEC
AVG GEEC
AVG GEEC
-------------------------------------------------------------------10.91
10.44
7.97
4.80
3.57
RUN No.
4 FOR Paraquat dichlor ON
Lucerne
* INPUT VALUES *
-------------------------------------------------------------------RATE (#/AC)
No.APPS &
SOIL SOLUBIL
APPL TYPE NO-SPRAY INCORP
ONE(MULT)
INTERVAL
Koc
(PPM )
(%DRIFT)
(FT)
(IN)
-------------------------------------------------------------------0.534( 1.058)
2 28
15743.0*******
GRHIFI( 6.6)
0.0
0.0
FIELD AND STANDARD POND HALFLIFE VALUES (DAYS)
-------------------------------------------------------------------METABOLIC DAYS UNTIL HYDROLYSIS
PHOTOLYSIS
METABOLIC COMBINED
(FIELD)
RAIN/RUNOFF
(POND)
(POND-EFF)
(POND)
(POND)
-------------------------------------------------------------------1000.00
2
N/A
0.000.00
******
2000.00
GENERIC EECs (IN MICROGRAMS/LITER (PPB))
Version 2.0 Aug 1, 2001
-------------------------------------------------------------------PEAK
MAX 4 DAY
MAX 21 DAY
MAX 60 DAY
MAX 90 DAY
GEEC
AVG GEEC
AVG GEEC
AVG GEEC
AVG GEEC
-------------------------------------------------------------------6.52
6.23
4.74
2.84
2.10
RUN No.
5 FOR Paraquat dichlor ON
Non select
* INPUT VALUES *
-------------------------------------------------------------------RATE (#/AC)
No.APPS &
SOIL SOLUBIL
APPL TYPE NO-SPRAY INCORP
ONE(MULT)
INTERVAL
Koc
(PPM )
(%DRIFT)
(FT)
(IN)
-------------------------------------------------------------------0.534( 2.076)
4 28
15743.0*******
GRHIFI( 6.6)
0.0
0.0
FIELD AND STANDARD POND HALFLIFE VALUES (DAYS)
-------------------------------------------------------------------METABOLIC DAYS UNTIL HYDROLYSIS
PHOTOLYSIS
METABOLIC COMBINED
(FIELD)
RAIN/RUNOFF
(POND)
(POND-EFF)
(POND)
(POND)
-------------------------------------------------------------------1000.00
2
N/A
0.000.00
******
2000.00
April 2016
32
GENERIC EECs (IN MICROGRAMS/LITER (PPB))
Version 2.0 Aug 1, 2001
-------------------------------------------------------------------PEAK
MAX 4 DAY
MAX 21 DAY
MAX 60 DAY
MAX 90 DAY
GEEC
AVG GEEC
AVG GEEC
AVG GEEC
AVG GEEC
-------------------------------------------------------------------12.84
12.27
9.33
5.59
4.14
The maximum Estimated Environmental Concentration (EEC) for paraquat dichloride when used in ParaKen 250 Herbicide for clover, forestry, lucerne, non-crop situations and non-selective weed control (barley
grass) high and low rate estimated by GENEEC2 were 0.00433 mg/L, 0.01091 mg/L, 0.00652 mg/L,
0.03223 mg/L and 0.01284 mg/L, respectively.
Calculation of acute risk quotients using GENEEC2 expected environmental concentrations
Table 8 gives calculated acute risk quotients for each trophic level considering EEC estimated by GENEEC2
and lowest relevant toxicity figures.
The calculations are based on a conservative model taking into account the degradation of the substance
and its adsorption potential in order to cover both run-off, drift input into water bodies. The model also
considers information about the application method to determine the drift input into water bodies.
Table 8 Acute risk quotients derived from the GENEEC2 model and toxicity data
Species
Peak EEC from
LC50 or EC50
GENEEC2 (mg/L)
(mg/L)
Acute RQ
Trigger value /
Presumption
Clover - 0.4 kg a.i./ha, 2 applications at 28 days interval
Fish
< 0.1 / Risk below
concern
10.85
0.0004
< 0.05 / Risk below
concern for threatened
species
0.00437
< 0.1 / Risk below
concern
Invertebrates
April 2016
1.2
0.0036
< 0.05 / Risk below
concern for threatened
species
33
Species
Peak EEC from
LC50 or EC50
GENEEC2 (mg/L)
(mg/L)
Acute RQ
Trigger value /
Presumption
< 0.1 / Risk below
concern
Algae Selenastrum
capricornutum
0.32
0.014
Algae - diatom
< 0.05 / Risk below
concern for threatened
species
> 0.5 / High risk
0.00055
(Navicula
pelliculosa)
7.94
> 0.05 / High risk for
threatened species
< 0.1 / Risk below
concern
Aquatic plant
0.098
0.045
(Lemna gibba)
< 0.05 / Risk below
concern for threatened
species
Forestry - 1 kg a.i./ha, 2 applications at 28 days interval
Fish
< 0.1 / Risk below
concern
10.85
0.001
< 0.1 / Risk below
concern
Invertebrates
1.2
0.009
(Daphnia magna)
Algae Selenastrum
capricornutum
0.01091
0.32
0.034
< 0.05 / Risk below
concern for threatened
species
> 0.5 / High risk
0.00055
19.84
Aquatic plant
0.098
(Lemna gibba)
Lucerne - 0.6 kg a.i./ha, 2 applications at 28 days interval
April 2016
< 0.05 / Risk below
concern for threatened
species
< 0.1 / Risk below
concern
Algae - diatom
(Navicula
pelliculosa)
< 0.05 / Risk below
concern for threatened
species
0.11
> 0.05 / High risk for
threatened species
0.1-0.5 / Risk can be
mitigated through
restricted use
> 0.05 / High risk for
threatened species
34
Species
Peak EEC from
LC50 or EC50
GENEEC2 (mg/L)
(mg/L)
Acute RQ
Trigger value /
Presumption
< 0.1 / Risk below
concern
10.85
Fish
0.0006
< 0.1 / Risk below
concern
Invertebrates
1.2
0.0054
(Daphnia magna)
Algae Selenastrum
capricornutum
< 0.05 / Risk below
concern for threatened
species
< 0.05 / Risk below
concern for threatened
species
< 0.1 / Risk below
concern
0.00652
0.32
0.02
Algae - diatom
< 0.05 / Risk below
concern for threatened
species
> 0.5 / High risk
0.00055
(Navicula
pelliculosa)
11.85
> 0.05 / High risk for
threatened species
< 0.1 / Risk below
concern
Aquatic plant
0.098
0.067
(Lemna gibba)
> 0.05 / High risk for
threatened species
Barley grass control – 1.5 kg a.i./ha, 4 applications at 28 days interval
Fish
< 0.1 / Risk below
concern
10.85
0.00297
< 0.1 / Risk below
concern
Invertebrates
(Daphnia magna)
0.03223
1.2
0.027
< 0.05 / Risk below
concern for threatened
species
< 0.1 / Risk below
concern
Algae Selenastrum
capricornutum
0.32
Algae - diatom
0.00055
April 2016
< 0.05 / Risk below
concern for threatened
species
0.1
> 0.05 / High risk for
threatened species
58.6
> 0.5 / High risk
35
Species
Peak EEC from
LC50 or EC50
GENEEC2 (mg/L)
(mg/L)
Acute RQ
(Navicula
pelliculosa)
Trigger value /
Presumption
> 0.05 / High risk for
threatened species
Aquatic plant
0.098
0.33
(Lemna gibba)
0.1-0.5 / Risk can be
mitigated through
restricted use
> 0.05 / High risk for
threatened species
Barley grass control, lower rate – 0.6 kg a.i./ha, 4 applications at 28 days interval
Fish
< 0.1 / Risk below
concern
10.85
0.0011
< 0.1 / Risk below
concern
Invertebrates
1.2
0.0107
(Daphnia magna)
Algae Selenastrum
capricornutum
< 0.05 / Risk below
concern for threatened
species
< 0.05 / Risk below
concern for threatened
species
< 0.1 / Risk below
concern
0.01284
0.32
0.04
Algae - diatom
< 0.05 / Risk below
concern for threatened
species
> 0.5 / High risk
0.00055
(Navicula
pelliculosa)
23.35
Aquatic plant
0.098
0.13
(Lemna gibba)
> 0.05 / High risk for
threatened species
0.1-0.5 / Risk can be
mitigated through
restricted use
> 0.05 / High risk for
threatened species
Non-crop situations – 1.5 kg a.i./ha, 4 applications at 28 days interval
Fish
< 0.1 / Risk below
concern
0.03223
April 2016
10.85
0.00297
< 0.05 / Risk below
concern for threatened
species
36
Species
Peak EEC from
LC50 or EC50
GENEEC2 (mg/L)
(mg/L)
Acute RQ
Trigger value /
Presumption
< 0.1 / Risk below
concern
Invertebrates
1.2
0.027
< 0.05 / Risk below
concern for threatened
species
(Daphnia magna)
< 0.1 / Risk below
concern
Algae Selenastrum
capricornutum
0.32
0.1
> 0.05 / High risk for
threatened species
Algae - diatom
> 0.5 / High risk
0.00055
(Navicula
pelliculosa)
58.6
> 0.05 / High risk for
threatened species
0.1-0.5 / Risk can be
mitigated through
restricted use
Aquatic plant
0.098
0.33
(Lemna gibba)
> 0.05 / High risk for
threatened species
Conclusion for the aquatic acute risk assessment using GENEEC2 data
Acute risks were below the level of concern for fish and aquatic invertebrates for all the use scenarios.
High acute risks for algae were observed for all use scenarios. High acute risks for threatened plant species
were observed for forestry, Lucerne, non selective weed control and non-crop situations.
Calculation of chronic risk quotients using GEENEC2 expected environmental concentrations
Table 9 gives calculated chronic risk quotients for each trophic level considering EEC estimated by
GENEEC2 and lowest relevant toxicity figures.
Table 9 Chronic risk quotients derived from the GENEEC2 model and toxicity data
Species
Relevant EEC from
NOEC
Chronic
Trigger value /
GENEEC2 (mg /L)*
(mg/L)
RQ
Presumption
Clover seed - 0.4 kg a.i./ha, 4 applications at 28 days interval
< 1 / Risk below concern
Invertebrates Daphnia
magna (21 d)
April 2016
0.00319
0.12
0.026
< 0.1 / Risk below
concern for threatened
species
37
Non-crop situations: Fence lines, streets, industrial - 1.5 kg a.i./ha, 4 applications at 28 days interval
< 1 / Risk below concern
Invertebrates Daphnia
magna (21 d)
0.02355
0.12
0.1965
> 0.1 / High chronic
risk to threatened
species
Forestry - 1 kg a.i./ha, 2 applications at 28 days interval
< 1 / Risk below concern
Invertebrates Daphnia
magna (21 d)
0.00797
0.12
0.066
< 0.1 / Risk below
concern for threatened
species
Lucerne - 0.6 kg a.i./ha, 2 applications at 28 days interval
< 1 / Risk below concern
Invertebrates Daphnia
magna (21 d)
0.00474
0.12
0.0395
< 0.1 / Risk below
concern for threatened
species
Barley grass control - 1.5 kg a.i./ha, 4 applications at 28 days interval
< 1 / Risk below concern
Invertebrates Daphnia
magna (21 d)
0.02355
0.12
0.19
> 0.1 / High chronic
risk to threatened
species
Barley grass control, low rate - 0.6 kg a.i./ha, 4 applications at 28 days interval
< 1 / Risk below concern
Invertebrates Daphnia
magna (21 d)
0.00933
0.12
0.077
< 0.1 / Risk below
concern for threatened
species
* EEC selected must be as close as possible from the exposure duration of the study selected for risk
assessment purpose.
Conclusion for the aquatic chronic risk assessment using GENEEC2 data
Chronic risks were below the level of concern for aquatic invertebrates, but high chornic risks for threatened
aquatic invertebrates species were observed for the application on non-crop situations and non-selective
control at the highest application rate of 1.5 kg paraquat dichloride per hectare. There were no data to
assess the chronic risks to fish. The staff consider that the lack of chronic data on fish does not prevent the
conclusion of the risk assessment.
AgDRIFT modelling
April 2016
38
Further modelling using the AgDRIFT® tool was undertaken in order to refine this result and provide an
indication of the extent of the measures that would need to be taken in order to manage the risks so that they
are reduced below the level of concern that is indicated in the modelling.
AgDRIFT® modelling does not allow determining EEC per se. AgDRIFT® modelling output is a buffer zone
determination to be respected in order to get a risk quotient < 1.
Output from the AgDRIFTmodel
The AgDRIFT® tool utilises buffer zones as a means of mitigating risks to non-target organisms, with higher
risks resulting in larger buffer zone distances as the model’s output. As such, the buffer zone outputs of the
model provide a relative measure of the risks to the environment and the extent of the mitigation measures
that should be applied. The results of the AgDRIFT ® assessment confirmed that measures should be taken
during use to ensure that waterways are not exposed to the substance.
Based on the application rates and proposed scenarios of use recommended for Para-Ken 250 Herbicide,
using coarse nozzles, the environmental fate characteristics and the lowest acute figure for the most
sensitive taxa (EC50 = 0.00055 mg/L) for paraquat dichloride on the diatom Navicula pelliculosa, the model
concludes that a buffer zone higher than 254 m (highest buffer zone possible to calculate in AgDrift) is
needed for all use scenarios. It should be pointed out that this buffer zone higher than 254 meters is already
applicable at 400 g a.i./ha, the lowest proposed application rate. Due to model limitations, it was not
possible to provide a quantitative estimate of exposure with known uncertainty, beyond the range of
AgDRIFT. The additional safety factor for threatened species was not taken into consideration because there
is currently no list of endangered algae species for NZ.
In conclusion, staff consider that there are no adequate mitigation measures to protect algae from the
application of Para-Ken 250 Herbicide.
6.5.
Groundwater risk assessment
Estimated concentrations of chemicals with Koc values greater than 9995 L/kg are beyond the scope of the
regression data used in SCI-GROW model. The staff consider that due to the high adsorption of paraquat
dichloride and the fact that it is almost immobile in the soil will preclude a potential risk of groundwater
contamination.
6.6. Sediment risk assessment
Sediments may act as both a sink for chemicals through sorption of contaminants to particulate matter, and a
source of chemicals through resuspension. Sediments integrate the effects of surface water contamination
April 2016
39
over time and space, and may thus present a hazard to aquatic communities (both pelagic and benthic)
which is not directly predictable from concentrations in the water column.
When results from whole-sediment tests with benthic organisms are available the PNECsed has to be
derived from these tests using assessment factors. However, the available sediment tests should be
carefully evaluated. Special attention should be given to the pathways through which the test organisms are
exposed to the chemical and the test protocol should carefully be checked to determine whether feeding with
unspiked food has possibly reduced exposure via sediment ingestion. For assessing the toxicity of spiked
sediment it is necessary to address adequately all possible routes of exposure. Sediment organisms can be
exposed via their body surfaces to substances in solution in the overlying water and in the pore water and to
bound substances by direct contact or via ingestion of contaminated sediment particles. The route that is
most important is strongly influenced by species-specific feeding mechanisms and the behaviour of the
organism in, or on, the sediment. Test design parameters can have a bearing on the route of uptake of a
substance.
The PNECsed is derived from the lowest available NOEC/EC10 obtained in long-term tests by application of
the following assessment factors and is then expressed as mg/kg of dry sediment:
Table 10 Assessment factors for derivation of PNECsed
Available test result
One long-term test (NOEC or EC10)
100
Two long-term tests (NOEC or EC10) with species representing different living and
feeding conditions
50
Three long-term tests (NOEC or EC10) with species representing different living
and feeding conditions
10
Using the toxicity figures from the tests with spiked sediment on the reproduction of Chironomus, and
dividing by the appropriate assessment factor of 100, the calculated PNEC sed is 1 mg/kg dry sediment for
paraquat dichloride.
PEClocal for sediment can be compared to the PNEC for sediment dwelling organisms. The concentration in
freshly deposited sediment is taken as the PEC for sediment, therefore, the properties of suspended matter
are used. The concentration in bulk sediment can be derived from the corresponding water body
concentration, assuming a thermodynamic partitioning equilibrium (see also Di Toro et al., 1991):
𝑃𝐸𝐶𝑙𝑜𝑐𝑎𝑙 𝑠𝑒𝑑 =
𝐾𝑝 𝑠𝑢𝑠𝑝 − 𝑤𝑎𝑡𝑒𝑟
× 𝑃𝐸𝐶 𝑙𝑜𝑐𝑎𝑙 𝑤𝑎𝑡𝑒𝑟 × 1000
𝑅𝐻𝑂 𝑠𝑢𝑠𝑝
Where
PEClocal water concentration in surface water during release episode based on GENEEC2 modelling (mg/L)
April 2016
40
Ksusp-water suspended matter-water partitioning coefficient = 5.65 (m 3/m3). Equation R.16-7 of REACH TGD
R16.
RHOsusp bulk density of suspended matter = 1150 (kg/m 3) Equation R.16-16 of REACH TGD R16.
PEClocal sed predicted environmental concentration in sediment (mg/kg)
The worst-case scenario for the concentration expected to be measured in pore-water is the expected
concentration in the water column (i.e. 0.00895 mg/L, according to GENEEC2), therefore
PEClocal sed = 0.043 mg/kg sediment for paraquat.
The risk for sediment-dwelling organisms is assessed as the ratio PECsed/PNECsed. This ratio is 0.043 for
paraquat.
Conclusion for the sediment risk assessment:
Risks for sediment dwelling organisms due to paraquat are below the level of concern (LoC < 1).
6.7. Terrestrial risk assessment
For terrestrial organisms, Toxicity-Exposure Ratios (TERs) are used for earthworms and birds, Hazard
Quotient (HQ) are used for terrestrial invertebrates and Risk Quotient (RQ) for bees. This convention results
in concern arising if a risk quotient is less than the trigger value for earthworms and more than a trigger value
for terrestrial invertebrates. LOC developed by the European Union and adopted by the Staff allowing
determining whether a substance poses an environmental risk are provided in the Table 11.
Table 11 Levels of concern as adopted by the Staff
Level of Concern (LOC)
Presumption
Acute TER
< 10
High risk
Chronic TER
<5
High risk
Acute TER
< 20
High risk
Chronic TER
< 10
High risk
Acute TER
< 100
High risk
Chronic TER
< 50
High risk
> 0.4
High risk
Earthworm/ Birds
Threatened bird species
Threatened soil organisms species
Bees
Acute RQ oral/contact
April 2016
41
Chronic RQ
>1
High risk
≥2
High risk
Terrestrial invertebrates
HQ in-field/off-field
For more details about the different factors used for calculating TER and RQ refer to the relevant reference
documents listed in Table 5.
6.7.1. Earthworm risk assessment
Soil Predicted Environmental Concentration (PEC) determination
Both acute and reproductive earthworm tests are static tests where the test substance is applied to the
system only once at the beginning. Therefore the nominal dose levels in the test match initial concentrations
in the field and thus it is appropriate to use initial PEC values (no time-weighted averages) for the acute as
well as the long-term TER.
The concentration of active substance in the soil is calculated on the basis of the FOCUS (1997) document
‘Soil persistence models and EU registration’
𝑃𝐸𝐶 𝑜𝑛𝑒 𝑎𝑝𝑝𝑙𝑖𝑐𝑎𝑡𝑖𝑜𝑛 (mg/kg soil) =
𝑎𝑝𝑝𝑙𝑖𝑐𝑎𝑡𝑖𝑜𝑛 𝑟𝑎𝑡𝑒 (kg a.i./ha)
× 100
75 𝑘𝑔 𝑠𝑜𝑖𝑙
Soil concentrations of the active ingredient are calculated by assuming the deposition would mix into the top
5 cm of soil, and this soil would have a bulk density of 1,500 kg/m 3, i.e. the deposition expressed in mg/m2
would mix into 75 kg of soil.
In case of multiple applications, the following formula has to be used:
𝑃𝐸𝐶 𝑚𝑢𝑙𝑡𝑖𝑝𝑙𝑒 𝑎𝑝𝑝𝑙𝑖𝑐𝑎𝑡𝑖𝑜𝑛𝑠 = 𝑃𝐸𝐶 𝑜𝑛𝑒 𝑎𝑝𝑝𝑙𝑖𝑐𝑎𝑡𝑖𝑜𝑛 ×
(1 − 𝑒 −𝑛𝑘𝑖 )
(1 − 𝑒 −𝑘𝑖 )
where:
n = number of applications
k = ln2/DT50 (day-1)
i = interval between two consecutive applications (days)
DT50 = half-life in soil (days) Use only DT 50 values of lab test done at 10-20 oC and pH between 5 and 9.
e = 2.718 (constant)
When there are DT50 values of several soils use GENEEC2 formula for determining the relevant DT50 to be
used.
PEC calculation results are summarized for each scenario in
Table 12 and Table 13.
Calculation of TERs
𝑇𝐸𝑅𝑎𝑐𝑢𝑡𝑒 =
April 2016
𝐿𝐷50
𝐸𝑠𝑡𝑖𝑚𝑎𝑡𝑒𝑑 𝐸𝑛𝑣𝑖𝑟𝑜𝑛𝑚𝑒𝑛𝑡𝑎𝑙 𝐶𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛
42
𝑇𝐸𝑅𝑙𝑜𝑛𝑔 − 𝑡𝑒𝑟𝑚 =
𝑁𝑂𝐸𝐶
𝐸𝑠𝑡𝑖𝑚𝑎𝑡𝑒𝑑 𝐸𝑛𝑣𝑖𝑟𝑜𝑛𝑚𝑒𝑛𝑡𝑎𝑙 𝐶𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛
Table 12 Acute in-field TER value for earthworms
Scenarios
Clover – 2 applications of 0.4 kg
a.i./ha at 28 days interval
Non-crop land (streets, fence
lines, industrial) - 4 applications of
1.5 kg a.i./ha at 28 days interval
PEC (mg/kg
LC50
soil)
(mg/kg soil)
Trigger value
TER acute
Presumption
1.06
>1306
7.77
>178
> 10 / Risk
below concern
Forestry – 2 applications of 0.6 kg
a.i./ha at 28 days interval
2.64
Lucerne – 2 application of 0.6 kg
a.i./ha at 28 days interval
1.58
>871
7.77
>178
Barley grass control – 4
applications of 1.5 kg a.i./ha at 28
days interval
/
>523
>1380
>100 / Risk
below concern
for threatened
species
Table 13 Acute off-field TER value for earthworms
Scenarios
Clover – 2 applications of 0.4 kg
a.i./ha at 28 days interval
Non-crop land (streets, fence
lines) - 4 applications of 1.5 kg
a.i./ha at 28 days interval
PEC (mg/kg
LC50
soil)
(mg/kg soil)
Trigger value
TER acute
Presumption
>19792
0.07
0.51
>2690
Forestry – 2 applications of 0.6 kg
a.i./ha at 28 days interval
0.17
>7917
Lucerne – 2 application of 0.6 kg
a.i./ha at 28 days interval
0.10
Barley grass control – 4
applications of 1.5 kg a.i./ha at 28
days interval
0.51
Conclusion for earthworm acute risk assessment
April 2016
/
>1380
>13195
>2690
> 10 / Risk
below concern
> 100 / Risk
below concern
for threatened
species
43
Risks were below the level of concern for off-field situations (outside the crop area) and for in-field (inside the
crop area) for earthworm species (including threatened species).
Conclusion for earthworm chronic risk assessment
There is no information about the chronic effects of paraquat dichloride to earthworms.
Conclusion for earthworm risk assessment
Risk to earthworms in-field (inside the crop area) and off-field (outside the crop area) were below the level of
concern.
6.7.2. Non-target plant risk assessment
Non target plants are non-crop plants located outside the treatment area.
Spray drift is considered the key exposure route for terrestrial plants located in the vicinity of the treated
area. The drift models produced by the BBA for the exposure assessment of aquatic organisms may be used
as a surrogate to cover the exposure assessment of terrestrial plants (Ganzelmeier et al., 1995, recently
updated by Rautmann et al., 2001).
Table 15 and Table 14 shows the drift expressed as percentage of the applied dose:
Table 15 Basic drift values for two applications
Ground deposition in % of the application rate (82nd percentiles)
Distance
Field
crops
Fruit crops
Grapevine
Hops
Vegetables
Ornamentals
Small fruit
Height
[m]
Early
late
Early
late
< 50 cm
1
2.38
3
Height
> 50
cm
2.38
25.53
12.13
2.53
7.23
17.73
7.23
5
0.47
16.87
6.81
1.09
3.22
9.60
0.47
3.22
10
0.24
9.61
3.11
0.35
1.07
4.18
0.24
1.07
15
0.16
5.61
1.58
0.18
0.56
2.57
0.16
0.56
20
0.12
2.59
0.9
0.11
0.36
1.21
0.12
0.36
30
0.08
0.87
0.4
0.06
0.19
0.38
0.08
0.19
Table 16 Basic drift values for four applications
Ground deposition in % of the application rate (74th percentiles)
April 2016
44
Distance
Field
crops
Fruit crops
Grapevine
Hops
Vegetables
Ornamentals
Small fruit
Height
[m]
Early
late
Early
late
< 50 cm
1
1.85
3
Height
> 50
cm
1.85
23.61
10.12
2.44
6.71
15.38
6.71
5
0.38
15.42
5.6
1.02
2.99
8.26
0.38
2.99
10
0.19
8.66
2.5
0.31
0.99
3.55
0.19
0.99
15
0.13
4.91
1.28
0.16
0.52
2.17
0.13
0.52
20
0.1
2.21
0.75
0.1
0.33
0.93
0.1
0.33
30
0.06
0.72
0.35
0.05
0.17
0.31
0.06
0.17
40
0.05
0.32
0.2
0.03
0.11
0.14
0.05
0.11
50
0.04
0.17
0.13
0.02
0.08
0.08
0.04
0.08
In fruit, grapevine and hops for herbicides (but not for plant growth regulators) that are applied to the ground,
the column “field crops” is applicable.
It should be noted that these drift data have been generated with regard to intake into surface waters. In
particular, there is no vegetation barrier between the spray boom and the collector plates. In terrestrial
scenarios, however, horizontal and vertical interception by in-crop or off-crop vegetation as well as patchy
distribution is relevant (“three-dimensional-situation“); thus, when more realistic drift data become available
they should be used.
The initial assessment should be conducted for a distance of 1 m from the field edge for field crops,
vegetables or ground applications such as for herbicides, and 3 m for other crops. Risk mitigation measures
based on buffer zones within the crop area can also be quantified using the above table. In case of aerial
applications a deposition rate of 100 % is assumed as the default, however this figure may be refined by
applying appropriate models (e.g. AgDrift).
This tier is a quantitative risk assessment following a RQ approach. Both effects and exposure are
expressed in terms of application rate (g/ha). Effects data are represented by ER 25 values from the studies,
also expressed as g/ha.
Table 17 TER value for non target plant – seedling emergence
April 2016
45
Exposure =
Scenarios
Drift (%)
drift x
EC25
application
(g ai/ha)
RQ
Trigger value
/ Presumption
rate (g ai/ha)
9.52
Clover
0.01
2.38 at 1 m
Non-crop land,
fence lines,
streets,
industrial sites
1.85 at 1 m
Forestry
25.53 at 1 m
Lucerne
2.38 at 1 m
Barley grass
control
1.85 at 1 m
< 1 / Below the
level of concern
0.03
27.75
255.3
< 1 / Below the
level of concern
950
14.28
27.75
0.27
< 1 / Below the
level of concern
0.02
< 1 / Below the
level of concern
0.03
< 1 / Below the
level of concern
Table 18 TER value for non target plant – vegetative vigour
Exposure =
Scenarios
Drift (%)
drift x
EC25
application
(g ai/ha)
RQ
Trigger value
/ Presumption
rate (g/ha)
Clover
2.38 at 1 m
9.52
Non-crop land:
fence lines,
streets,
industrial sites
1.85 at 1 m
27.75
15
0.63
< 1 / Risk below
concern
1.85
>1 / High risk
Non-crop land:
fence lines,
streets,
industrial sites
0.38 at 5 m
5.7
Forestry
25.53 at 1 m
255.3
17.02
>1 / High risk
Forestry
16.87 at 5 m
168.7
11.2
>1 / High risk
Forestry
9.61 at 10 m
96.1
6.4
>1 / High risk
Forestry
5.61 at 15 m
56.1
3.74
>1 / High risk
April 2016
0.38
< 1 / Risk below
concern
46
Forestry
2.59 at 20 m
25.9
0.87 at 30 m
8.7
Lucerne
2.38 at 1 m
14.28
Barley grass
control
1.85 at 1m
27.75
Barley grass
control
0.38 at 5 m
5.7
Forestry
1.7
>1 / High risk
0.58
< 1 / Risk below
concern
0.952
< 1 / Risk below
concern
1.85
0.38
>1 / High risk
< 1 / Risk below
concern
The approach for threatened species is based on RQ and the NOEC from the same studies used previously.
Table 19 TER value for non target plant threatened species
Exposure =
Scenarios
Drift (%)
drift x
NOEC
application
(g ai/ha)
RQ
Trigger value /
Presumption
rate (g/ha)
Clover
Fence lines,
streets,
Forestry
Lucerne
April 2016
2.38 at 1 m
9.52
4
2.38
> 1 / High risk
0.47 at 5 m
1.88
4
0.47
< 1 / Below concern
1.85 at 1 m
27.75
4
6.94
> 1 / High risk
0.38 at 5 m
5.7
4
1.425
> 1 / High risk
0.19 at 10 m
2.85
4
0.71
< 1 / Below concern
25.53 at 3 m
255.3
4
63.825
> 1 / High risk
16.87 at 5 m
168.7
4
42.175
> 1 / High risk
9.61 at 10 m
96.1
4
24.025
> 1 / High risk
5.61 at 15 m
56.1
4
14.025
> 1 / High risk
2.59 at 20 m
25.9
4
6.475
> 1 / High risk
0.87 at 30 m
8.7
4
2.175
> 1 / High risk
0.4 at 40 m
4.00
4
1.0
> 1 / High risk
0.22 at 50 m
2.20
4
0.6
< 1 / Below concern
2.38 at 1 m
14.28
4
3.57
> 1 / High risk
0.47 at 5 m
2.82
4
0.705
< 1 / Below concern
1.85 at 1 m
27.75
4
6.9375
> 1 / High risk
47
Barley grass
control
0.38 at 5 m
5.7
0.19 at 10 m
2.85
4
1.425
> 1 / High risk
0.7125
< 1 / Below concern
4
Conclusion for non target plant risk assessment
The risks to seedling emergence were below the level of concern for all use scenarios. The risks to
vegetative vigour were below the level of concern for the uses on clover and Lucerne. However, high risks to
vegetative vigour of non-target plants were observed for the uses on non-crop land, forestry and barley grass
control. High risks were observed for threatened native terrestrial plants for all the uses.
The following downwind buffer zones must be observed in order to protect non-crop plants from
unacceptable levels of spray drift from the application of Para-Ken 250 Herbicide:
Non-crop situations: 5 meters
Forestry: 30 meters
Barley grass control: 5 meters
For the protection of threatened native terrestrial plants the following advisory downwind buffer zones must
be observed:
Clover: 5 meters
Non-crop situations: 10 meters
Forestry: 50 meters
Lucerne: 5 meters
Barley grass control: 10 meters
6.7.3. Bird risk assessment
EPA uses EFSA’s Bird model and Excel© spreadsheets14 freely available on EFSA’s website to assess the
risks to birds.
The methodology calculates TERs where exposure is calculated as the dose that a bird will receive when
feeding in crops that have been sprayed. To avoid doing detailed evaluations for low risk scenarios,
assessments are performed in tiers of increasing complexity.
The steps for the acute assessment are:
14

Screening assessment

Tier I assessment
different spreadsheets for spray application, granular application and seed treatment.
For bait applications a spreadsheet with Daily Food Intake of NZ relevant species is available (Crocker et al., 2002).
April 2016
48

Higher tier assessment
The steps for the reproductive assessment are:

Screening assessment

Phase-specific approach assessment

Higher tier assessment
Progression to the next tier is only made if the threshold for concern is exceeded at the previous tier.
Screening risk assessment

Determination of levels of exposure
The principles underlying the exposure assessment are the same for all assessments other than
higher tier assessments in which more specific field exposure data may be used. The dose that a
bird receives (Daily Dietary Dose or DDD) is calculated from the application rate and a so-called
‘Shortcut value’ for the Residue per Unit Dose (RUD), reflecting the concentration on the bird’s food
and the quantity of food consumed. Quantities consumed are based on a bird’s energy
requirements, its energy assimilation and the energy content of its food (dry weight). Birds’ energy
requirements are based on an algorithm based on bodyweight and bird type (e.g. passerine/nonpasserine). For further details, refer to EFSA’ technical guidance document.
Both screening step assessments (acute and reproduction) select from 6 ‘indicator species’ each
applicable to a particular type of crop. They are not real species, but, by virtue of their size and
feeding habits, their exposure is considered worst-case for birds in a particular crop type. For
example, the representative species for orchards is described as a ‘small insectivorous bird’. It is
assumed that the relevant indicator species feeds only on contaminated food and the concentration
of pesticide on the food is not affected by the growth stage of the crop. Thus, the exposure
assessment is expressed as follows depending on the number of applications:
For acute test:
𝐷𝐷𝐷 𝑜𝑛𝑒 𝑎𝑝𝑝𝑙𝑖𝑐𝑎𝑡𝑖𝑜𝑛 = 𝑎𝑝𝑝𝑙𝑖𝑐𝑎𝑡𝑖𝑜𝑛 𝑟𝑎𝑡𝑒 (𝑘𝑔/ℎ𝑎) × 𝑠ℎ𝑜𝑟𝑡𝑐𝑢𝑡 𝑣𝑎𝑙𝑢𝑒
𝐷𝐷𝐷 𝑚𝑢𝑙𝑡𝑖𝑝𝑙𝑒 𝑎𝑝𝑝𝑙𝑖𝑐𝑎𝑡𝑖𝑜𝑛𝑠 = 𝐷𝐷𝐷 𝑜𝑛𝑒 𝑎𝑝𝑝𝑙𝑖𝑐𝑎𝑡𝑖𝑜𝑛 × 𝑀𝐴𝐹90
For reproduction test:
𝐷𝐷𝐷 = 𝑎𝑝𝑝𝑙𝑖𝑐𝑎𝑡𝑖𝑜𝑛 𝑟𝑎𝑡𝑒 (𝑘𝑔/ℎ𝑎) × 𝑠ℎ𝑜𝑟𝑡𝑐𝑢𝑡 𝑣𝑎𝑙𝑢𝑒 × 𝑇𝑊𝐴 ∗ × 𝑀𝐴𝐹𝑚𝑒𝑎𝑛
*if toxic effect is considered to be caused by long-term exposure, use TWA = 0.53 (estimates time-weighted exposure over 21 days
assuming a default DT50 of 10 days).
The exposure to paraquat dichloride for bird acute dietary and reproductive screening assessments is shown
in the Table 20 and Error! Reference source not found. respectively
The methodology calculates TERs where exposure is calculated as the dose that a bird will receive when
feeding in crops that have been sprayed. To avoid doing detailed evaluations for low risk scenarios,
assessments are performed in tiers of increasing complexity.
April 2016
49
The steps for the acute assessment are:

Screening assessment

Tier I assessment

Higher tier assessment
The steps for the reproductive assessment are:

Screening assessment

Phase-specific approach assessment

Higher tier assessment
Progression to the next tier is only made if the threshold for concern is exceeded at the previous tier.
Screening risk assessment

Determination of levels of exposure
The principles underlying the exposure assessment are the same for all assessments other than
higher tier assessments in which more specific field exposure data may be used. The dose that a
bird receives (Daily Dietary Dose or DDD) is calculated from the application rate and a so-called
‘Shortcut value’ for the Residue per Unit Dose (RUD), reflecting the concentration on the bird’s food
and the quantity of food consumed. Quantities consumed are based on a bird’s energy
requirements, its energy assimilation and the energy content of its food (dry weight). Birds’ energy
requirements are based on an algorithm based on bodyweight and bird type (e.g. passerine/nonpasserine). For further details, refer to EFSA’ technical guidance document.
Both screening step assessments (acute and reproduction) select from 6 ‘indicator species’ each
applicable to a particular type of crop. They are not real species, but, by virtue of their size and
feeding habits, their exposure is considered worst-case for birds in a particular crop type. For
example, the representative species for orchards is described as a ‘small insectivorous bird’. It is
assumed that the relevant indicator species feeds only on contaminated food and the concentration
of pesticide on the food is not affected by the growth stage of the crop. Thus, the exposure
assessment is expressed as follows depending on the number of applications:
For acute test:
𝐷𝐷𝐷 𝑜𝑛𝑒 𝑎𝑝𝑝𝑙𝑖𝑐𝑎𝑡𝑖𝑜𝑛 = 𝑎𝑝𝑝𝑙𝑖𝑐𝑎𝑡𝑖𝑜𝑛 𝑟𝑎𝑡𝑒 (𝑘𝑔/ℎ𝑎) × 𝑠ℎ𝑜𝑟𝑡𝑐𝑢𝑡 𝑣𝑎𝑙𝑢𝑒
𝐷𝐷𝐷 𝑚𝑢𝑙𝑡𝑖𝑝𝑙𝑒 𝑎𝑝𝑝𝑙𝑖𝑐𝑎𝑡𝑖𝑜𝑛𝑠 = 𝐷𝐷𝐷 𝑜𝑛𝑒 𝑎𝑝𝑝𝑙𝑖𝑐𝑎𝑡𝑖𝑜𝑛 × 𝑀𝐴𝐹90
For reproduction test:
𝐷𝐷𝐷 = 𝑎𝑝𝑝𝑙𝑖𝑐𝑎𝑡𝑖𝑜𝑛 𝑟𝑎𝑡𝑒 (𝑘𝑔/ℎ𝑎) × 𝑠ℎ𝑜𝑟𝑡𝑐𝑢𝑡 𝑣𝑎𝑙𝑢𝑒 × 𝑇𝑊𝐴 ∗ × 𝑀𝐴𝐹𝑚𝑒𝑎𝑛
*if toxic effect is considered to be caused by long-term exposure, use TWA = 0.53 (estimates time-weighted exposure over 21 days
assuming a default DT50 of 10 days).
The exposure to paraquat dichloride for bird acute dietary and reproductive screening assessments is shown
in the Table 20.
April 2016
50
Table 20 Exposure of birds for acute and reproduction screening assessment
Crop &
BBCH class
Indicator
(where
species2
appropriate)1
Application
Short-
MAF
rate
cut value
(90th
(kg/ha)
(90th%)3
%)4
No of
applications
DDD
Clover (legume forage), 2 applications of 0.4 kg a.i./ha at 28 days interval
Acute
158.8
Small omnivorous
bird
0.4
Long-term
69.87
1.1
2
64.8
15.11
Lucerne (legume forage), 2 applications of 0.6 kg a.i./ha at 28 days interval
Acute
158.8
Small omnivorous
bird
0.6
Long-term
104.81
1.1
2
64.8
22.67
Non selective weed control (legume forage), 4 applications of 0.6 kg a.i./ha at 28 days interval
Acute
158.8
Small omnivorous
bird
1.1
0.6
Long-term
104.81
4
64.8
1.2
24.73
Forestry, 2 application of 1 kg a.i./ha at 28 days interval
Acute
46.8
Small
insectivorous bird
1
Long-term
51.48
1.1
2
18.2
10.61
Non-crop land, 4 applications of 1.5 kg a.i./ha at 28 days interval
Acute
April 2016
1.5
24.7
1.1
4
40.76
51
Long-term
1
EFSA, 2009, Table 5 p27
2
EFSA, 2009, Table 6 p28
3
EFSA, 2009, Table 6 p28
4
EFSA, 2009, Table 7 p29
Small
granivorous bird
1 EFSA,
2009, Table 5 p27
2 EFSA,
2009, Table 10 p34
3
11.4
1.2
10.88
EFSA, 2009, Table 10 p34
4 EFSA,
2009, Table 11 p34
5The
exposure assessment of the reproduction assessment uses time-weighted average (TWA) exposure
estimates over 1, 2, 3 or 21 days for different phases of the assessment. 1 day = 1.0; 2 days = 0.93; 3 days = 0.9;
21 days = 0.53
Note about TWA:
Table 21 Measures of exposure and toxicity used in the reproduction assessment
Breeding phase
Pair formation/
breeding site
selection
Copulation and egg
laying (5 days prelaying through end of
laying
Incubation and
hatching
15
From acute study.
April 2016
Test endpoint used as
Short-term
surrogate
exposure
0.1 x LD5015
1 day DDD
21 day TWA DDD
NOAEL for the number of eggs
laid per hen
1 day DDD
21 day TWA DDD
NOAEL for mean eggshell
thickness
1 day DDD
21 day TWA DDD
0.1 x LD50
1 day DDD
21 day TWA DDD
NOAEL for proportion of viable
eggs/eggs set/hen
1 day DDD
21 day TWA DDD
Long-term exposure
52
Juvenile growth and
survival until fledging
NOAEL for proportion of
hatchlings/viable eggs/hen
3 day TWA DDD
21 day TWA DDD
0.1 x LD50 (extrinsic adult)
2 day TWA DDD
21 day TWA DDD
0.1 x LD50 (extrinsic juvenile)
1 day DDD based on
chick shortcut values of
3.8 and 22.716
21 day TWA DDD based
on chick shortcut value
of 3.8 and 22.73
NOAEL for proportion of 14 day
old juveniles/number of
hatchlings/hen
3 day TWA DDD
21 day TWA DDD
0.1 x LD50
1 day DDD based on
chick shortcut values of
3.8 and 22.73
21 day TWA DDD based
on chick shortcut value
of 3.8 and 22.73
NOAEL for 14 day old juvenile
weights/hen
3 day TWA DDD
21 day TWA DDD
Post-fledging
survival
2 from
acute study
two values are to account for ground and foliar dwelling arthropods with mean residue unit doses of 3.5 and
21 respectively. Assessments are made with both values. If TER are exceeded with either value, then an
assessment based on the actual composition of the diet of relevant species.
3 The
Calculation of TERs
TER calculations are detailed in Table 22.
Table 22 TER values for acute dietary and reproductive risk assessment – Screening assessment
Toxicity
Birds type
DDD
endpoint value
TER ratio
(mg/kg bw/d)
Trigger value /
Presumption
Clover - 2 applications of 0.4 kg a.i./ha at 28 days interval
< 10 / High risk
Acute
Long-term
16
Small
omnivorous bird
69.87
LD50 = 35
0.5
< 20 / High risk for
threatened
species
15.11
NOEC = 2.8
0.2
< 5 / High risk
The two values are to account for ground and foliar dwelling arthropods with mean residue unit doses of 3.5 and 21
respectively. Assessments are made with both values. If TER are exceeded with either value, then an assessment
based on the actual composition of the diet of relevant species.
April 2016
53
Toxicity
Birds type
DDD
endpoint value
TER ratio
(mg/kg bw/d)
Trigger value /
Presumption
< 10 / High risk for
threatened
species
Lucerne, 2 applications of 0.6 kg a.i./ha at 28 days interval
< 10 / High risk
Acute
104.81
LD50 = 35
0.3
Small
omnivorous bird
Long-term
< 20 / High risk for
threatened
species
< 5 / High risk
22.67
NOEC = 2.8
0.1
< 10 / High risk for
threatened
species
Non selective weed control (pastures) - 4 applications of 0.6 kg a.i./ha at 28 days interval
< 10 / High risk
Acute
104.81
LD50 = 35
0.3
Small
omnivorous bird
Long-term
< 20 / High risk for
threatened
species
< 5 / High risk
24.73
NOEC = 2.8
0.1
< 10 / High risk for
threatened
species
Non selective weed control (pastures) - 4 applications of 1.5 kg a.i./ha at 28 days interval
< 10 / High risk
Acute
< 20 / High risk for
threatened
species
LD50 = 35
Small
omnivorous bird
< 5 / High risk
Long-term
< 10 / High risk for
threatened
species
NOEC = 2.8
Forestry, 2 applications of 1 kg a.i./ha at 28 days interval
< 10 / High risk
Acute
Long-term
April 2016
Small
insectivorous
bird
51.48
LD50 = 35
0.7
< 20 / High risk for
threatened
species
10.61
NOEC = 2.8
0.3
< 5 / High risk
54
Toxicity
Birds type
DDD
endpoint value
TER ratio
(mg/kg bw/d)
Trigger value /
Presumption
< 10 / High risk for
threatened
species
Non-crop land, 4 applications of 1.5 kg a.i./ha at 28 days interval
< 10 / High risk
Acute
40.76
LD50 = 35
0.9
Small
granivorous bird
Long-term
< 20 / High risk for
threatened
species
< 5 / High risk
10.88
NOEC = 2.8
0.3
< 10 / High risk for
threatened
species
Conclusion for bird risk assessment (screening)
Both acute and chronic screening risk assessment indicates high risks for birds (including threatened
species) for all scenarios of use. Therefore, the risk assessment has to be refined.
Tier 1 risk assessment
Tier 1 uses the same general approach as the screening assessment but requires more specific exposure
scenarios. The first step is to identify all general focal species listed in Table I.1 (Annex I) of the EFSA’
technical guidance document that are relevant for the intended use(s).
In the Tier 1 acute and phase-specific reproduction assessments exposure is calculated for generic focal
species’, applicable to particular crops. Such assessments refine the screening step assessments in that:
 there are more bird ‘species’ (19) and crop options (21);
 the growth stage of the crop is taken into account, affecting the residues on the feed;
 more than one bird species may be considered for any one crop;
 a bird’s diet can be calculated to include more than one food item.
The larger number of bird species, crop types and growth stages of the crops leads to a total of 138 RUD
shortcut options, each with a mean and 90th percentile value.
Determination of levels of exposure
For each generic focal species the DDD is presented in Table 20.
April 2016
55
Calculation of TERs (Tier 1)
The TER calculations in the frame of the Tier 1 assessment are detailed in the Table 23. The toxicity figures
are the same than those considered in the screening assessment.
Table 23 TER values for acute dietary and reproductive risk assessment - Tier 1 assessment
Crop &
BBCH class
Generic focal
(where
species1
appropriate)
Short-cut
value
(90th%)
Trigger
TER ratio
2
value /
Presumption
Clover – 2 applications of 0.4 kg a.i./ha at 28 days interval
< 10 / High Risk
Acute
25.2
BBCH >20
3.2
Small insectivorous bird
“wagtail”
< 20 / High risk
for threatened
species
< 5 / High risk
Chronic
9.7
1.7
< 10 / High risk
for threatened
species
> 10 / Risk below
concern
Acute
7.4
BBCH > 50
10.7
Small granivorous bird
“finch”
< 20 / High risk
for threatened
species
< 5 / High risk
Chronic
3.4
3.5
< 10 / High risk
for threatened
species
> 10 / Risk below
concern
Acute
7.2
BBCH > 50
11.7
Small omnivorous bird
“lark”
< 20 / High risk
for threatened
species
< 5 / High risk
Chronic
April 2016
3.3
3.6
< 10 / High risk
for threatened
species
56
< 10 / High risk
Acute
26.8
BBCH 10-19
3.0
Small insectivorous bird
“wagtail”
< 20 / High risk
for threatened
species
< 5 / High risk
Chronic
11.3
1.1
< 10 / High risk
for threatened
species
< 10 / High Risk
Acute
24.7
BBCH 10-49
3.2
Small granivorous bird
“finch”
Chronic
< 20 / High risk
for threatened
species
< 5 / High risk
11.4
1.1
< 10 / High risk
for threatened
species
< 10 / High Risk
Acute
24.0
BBCH 10-49
3.3
Small omnivorous bird
“lark”
< 20 / High risk
for threatened
species
< 5 / High risk
Chronic
10.9
1.1
< 10 / High risk
for threatened
species
< 10 / High risk
Acute
Chronic
55.6
BBCH 21-49,
leaf
development
1.4
Medium
herbivorous/granivorous
bird “pigeon”
< 20 / High risk
for threatened
species
< 5 / High risk
22.7
0.5
< 10 / High risk
for threatened
species
Lucerne (legume forage) – 2 applications of 0.6 kg a.i./ha at 28 days interval
< 10 / High Risk
Small insectivorous bird
“wagtail”
Acute
25.2
2.1
< 20 / High risk
for threatened
species
9.7
0.8
< 5 / High risk
BBCH >20
Chronic
April 2016
57
< 10 / High risk
for threatened
species
< 10 / High Risk
Acute
7.4
BBCH > 50
7.2
Small granivorous bird
“finch”
Chronic
< 20 / High risk
for threatened
species
< 5 / High risk
3.4
2.4
< 10 / High risk
for threatened
species
< 10 / High Risk
Acute
7.2
BBCH > 50
7.4
Small omnivorous bird
“lark”
Chronic
< 20 / High risk
for threatened
species
< 5 / High risk
3.3
2.4
< 10 / High risk
for threatened
species
< 10 / High Risk
Acute
26.8
BBCH 10-19
2.0
Small insectivorous bird
“wagtail”
< 20 / High risk
for threatened
species
< 5 / High risk
Chronic
11.3
0.7
< 10 / High risk
for threatened
species
< 10 / High Risk
Acute
24.7
BBCH 10-49
2.1
Small granivorous bird
“finch”
Chronic
< 20 / High risk
for threatened
species
< 5 / High risk
11.4
0.7
< 10 / High risk
for threatened
species
< 10 / High Risk
Small omnivorous bird
“lark”
Acute
Chronic
April 2016
BBCH 10-49
24.0
2.2
< 20 / High risk
for threatened
species
10.9
0.7
< 5 / High risk
58
< 10 / High risk
for threatened
species
< 10 / High Risk
Acute
55.6
BBCH 21-49,
leaf
development
1.0
Medium
herbivorous/granivorous
bird “pigeon”
Chronic
< 20 / High risk
for threatened
species
< 5 / High risk
22.7
0.4
< 10 / High risk
for threatened
species
Non selective weed control (barley grass) – 4 applications of 0.6 kg a.i./ha at 28 days interval
< 10 / High risk
Acute
25.2
BBCH >20
2.1
Small insectivorous bird
“wagtail”
< 20 / High risk
for threatened
species
< 5 / High risk
Chronic
9.7
0.8
< 10 / High risk
for threatened
species
< 10 / High risk
Acute
7.4
BBCH > 50
7.2
Small granivorous bird
“finch”
Chronic
< 20 / High risk
for threatened
species
< 5 / High risk
3.4
2.2
< 10 / High risk
for threatened
species
< 10 / High risk
Acute
7.2
BBCH > 50
Small omnivorous bird
“lark”
Chronic
April 2016
Small insectivorous bird
“wagtail”
< 20 / High risk
for threatened
species
< 5 / High risk
3.3
BBCH 10-19
Acute
7.4
2.2
< 10 / High risk
for threatened
species
< 10 / High risk
26.8
2.0
< 20 / High risk
for threatened
species
59
< 5 / High risk
Chronic
11.3
0.6
< 10 / High risk
for threatened
species
< 10 / High risk
Acute
24.0
BBCH 10-49
2.1
Small granivorous bird
“finch”
Chronic
< 20 / High risk
for threatened
species
< 5 / High risk
11.4
0.6
< 10 / High risk
for threatened
species
< 10 / High risk
Acute
24.0
2.2
Small omnivorous bird
“lark”
< 20 / High risk
for threatened
species
< 5 / High risk
BBCH 10-49
Chronic
10.9
0.7
< 10 / High risk
for threatened
species
< 10 / High risk
Acute
55.6
BBCH 21-49,
leaf
development
1.0
Medium
herbivorous/granivorous
bird “pigeon”
Chronic
< 20 / High risk
for threatened
species
< 5 / High risk
12.5
0.6
< 10 / High risk
for threatened
species
Forestry, 2 applications of 1 kg a.i./ha at 28 days interval
< 10 / High risk
Acute
27.4
Not crop
directed
application all
season
1.4
Small granivorous bird
“finch”
< 20 / High risk
for threatened
species
< 5 / High risk
Chronic
12.6
0.4
< 10 / High risk
for threatened
species
Acute
7.4
4.3
< 10 / High risk
April 2016
60
Not crop
directed
application all
season
< 20 / High risk
for threatened
species
Small insectivorous/worm
feeding species “thrush”
Chronic
< 5 / High risk
2.7
1.8
< 10 / High risk
for threatened
species
Non-crop land (bare soil), 4 applications of 1.5 kg a.i./ha at 28 days interval
< 10 / High risk
Acute
24.7
0.9
BBCH < 10
Small granivorous bird
“finch”
Chronic
< 20 / High risk
for threatened
species
< 5 / High risk
11.4
0.3
< 10 / High risk
for threatened
species
< 10 / High risk
Acute
10.9
BBCH < 10
1.9
Small insectivorous bird
“wagtail”
Chronic
< 20 / High risk
for threatened
species
< 5 / High risk
5.9
0.5
< 10 / High risk
for threatened
species
< 10 / High risk
Acute
17.4
BBCH < 10
Small omnivorous bird
“lark”
Chronic
1 EFSA,
2009, Table I.1, Annex I
2 EFSA,
2009, Table I.1, Annex I
3 EFSA,
2009 - Table 11 p34
Conclusion for bird risk assessment (Tier 1)
April 2016
1.2
< 20 / High risk
for threatened
species
< 5 / High risk
8.2
0.4
< 10 / High risk
for threatened
species
61
For the uses on clover, there were high acute risks for all crops stages with the exception of application after
BBCH >50, where high risks were observed only for threatened bird species. There were high chronic risks
(including for threatened bird species) for all crop stages.
For the uses on Lucerne there were high acute risks and high chronic risks for all crops stages.
For the uses on selective weed control (barley grass) at 0.6 kg a.i./ha there were high acute risks and high
chronic risks for all crops stages. The risks were high with this lower application rate, thus staff did not
modelled the application on barley at 1.5 kg a.i./ha, hence the risks are also deemed to be higher than the
level of concern.
For the uses on forestry there were high acute and high chronic risks.
For the uses on non-crop situations there were high acute and high chronic risks.
Refinement for bird risk assessment (Tier I)
Staff assessed separately the risk for birds following the application of Para-Ken 250 Herbicide in crop
(agricultural) use and non-crop situations (industrial, fence lines and stock yards) taking into account the
method of application of Para-Ken 250 Herbicide. It is recognized that the intended uses for high volume
broadcast on agricultural fields represent a higher potential risk to birds than the application using a
knapsack in non-crop situations.
Potential risk to birds from the application to non-crop situations
The application using knapsack around industrial sites, fence lines, stock yards to clean up weeds minimizes
residue deposition on foliage, thus this method of application is not expected to result in a significant food
contamination for birds. Therefore, the acute and chronic risk to birds resulting from the application of ParaKen 250 Herbicide using knapsack for spot treatment on non-crop situations is expected to be of low
concern for birds. The staff consider that it is appropriate to apply controls to ensure that the knapsack
application is carried out using coarse droplets to minimize spray drift to nearby foliage.
Potential acute risk to birds
The estimated acute TER exceed the level of concern following a broadcast spray application of Para-Ken
250 Herbicide to clover, Lucerne, barley grass control and forestry. The staff consider that due to the
environmental fate characteristics of paraquat dichloride, namely its strong adsorption to biological materials
leading to paraquat becoming less bioavailable, the risk to birds only exists shortly after application and
therefore once the applied paraquat has dried its risk is greatly reduced.
April 2016
62
However, the staff consider that there are no adequate mitigation measures to control the potential acute
risks to bird’s species following the application of Para-Ken 250 Herbicide to clover, Lucerne, barley grass
control and forestry, thus these risks will remain unmanageable.
Potential reproductive risk to birds
The estimated chronic TER exceed the level of concern for all bird types following a broadcast spray
application of Para-Ken 250 Herbicide to clover, Lucerne, barley grass control and forestry. The chronic risks
were estimated using the NOEC of 2.8 mg/kg bw/d selected from the reproduction study in the Mallard duck
based on the reduction in the percentage of viable eggs, eggs set, normality of hatching, and number of 14day old survival. The proposed use of Para-Ken 250 Herbicide will potential result in a risk to the
reproduction of birds. It was not possible to refine the risk assessment due to lack of appropriate higher tier
data (field studies) for the representative uses. Staff consider that the high reproductive risks to birds will
remain unmanageable.
Secondary poisoning
Paraquat dichloride is not bioaccumulative so no risk assessment for secondary poisoning is necessary for
this active ingredient.
6.7.4. Bee risk assessment
The risk to bees is assessed as follows:
Tier1- screening level risks
If a reasonable potential for exposure to the pesticide is identified, a screening-level risk assessment is
conducted. This step involves a comparison of Tier I estimated exposure concentrations (EECs) for contact
and oral routes of exposure to adults and larvae to Tier I acute and chronic levels of effects to individual
bees using laboratory-based studies. The conservatism of the Tier I screening-level risk quotient (RQ) value
results primarily from the model-generated exposure estimates that, while intended to represent
environmentally relevant exposure levels, are nonetheless considered high-end estimates. The resulting
acute and chronic RQ values are then compared to the corresponding level of concern (LOC) values for
acute and chronic risk (i.e., 0.4 and 1.0, respectively). Generally, if RQ values are below their respective
LOCs, a presumption of minimal risk is made, since the Tier I risk estimation methods are designed to be
conservative.
EEC are calculated as follows:
Measurement
Exposure
Exposure estimate
Acute effect
Chronic effect
endpoint
route
(EEC)*
endpoint
endpoint#
April 2016
63
Foliar application
Individual
survival (adults)
Individual
survival (adults)
Brood size and
success
Contact
Application rate (kg
Acute
ai/ha) x 2.4 µg ai/bee
contact LD50
Application rate (kg
Diet
ai/ha) x 98 µg ai/g x
0.292 g/day
Acute oral
LD50
Application rate (kg
Diet
ai/ha) x 98 µg ai/g x
None
Chronic adult oral
NOAEL (effects to
survival or longevity)
Chronic larval oral
Larval LD50
0.124 g/day
NOAEL (effects to adult
emergence, survival)
Soil treatment
Individual
survival (adults)
Brood size and
success
Diet
Diet
Briggs EEC x 0.292
Acute oral
g/day
LD50
Briggs EEC x 0.124
g/day
Chronic adult oral
NOAEL (effects to
survival or longevity)
Chronic larval oral
Larval LD50
NOAEL (effects to adult
emergence, survival)
Seed treatment&
Individual
survival (adults)
Brood size and
success
Diet
1 µg ai/g x 0.292 g/day
Acute oral
LD50
Chronic adult oral
NOAEL (effects to
survival or longevity)
Chronic larval oral
Diet
1 µg ai/g x 0.124 g/day
Larval LD50
NOAEL (effects to adult
emergence, survival)
Tree trunk application**
Individual
survival (adults)
Brood size and
success
Diet
Diet
µg ai applied to tree/g
Acute oral
foliage x 0.292 g/day
LD50
µg ai applied to tree/g
foliage x 0.124 g/day
Chronic adult oral
NOAEL (effects to
survival or longevity)
Chronic larval oral
Larval LD50
NOAEL (effects to adult
emergence, survival)
* Based on food consumption rates for larvae (0.124 g/day) and adult (0.292 g/day) worker bees and concentration in pollen and nectar
** Note that concentration estimates for tree applications are specific to the type and age of the crop to which the chemical is applied.
April 2016
64
# To calculate RQs for chronic effects, NOAEC can be used as the effect endpoint to compare with the exposure estimate in
concentration
& Assume that pesticide concentration in pollen and nectar of seed treated crops is 1 mg a.i./kg (1 μg a.i./g). • No adjustment is made
for application rate (Based on EPPO’s recommended screening value)
𝐴𝑐𝑢𝑡𝑒 𝑅𝑄 =
𝐶ℎ𝑟𝑜𝑛𝑖𝑐 𝑅𝑄 =
𝐸𝐸𝐶
𝐿𝐷50
𝐸𝐸𝐶
𝑁𝑂𝐴𝐸𝐿
Toxicity
Use scenario
Application
EEC (µg
endpoint
rate (kg ai/ha)
ai/bee)
value (µg
RQ
Trigger value
/Presumption
ai/bee)
Clover
Acute / Adult
bees - contact
Acute / Adult
bees - oral
0.4
0.96
9.26
0.10
0.4
11.45
9.06
1.26
< 0.4 / No
concern
>0.4 / High
risk
Non-crop situations: fence lines, streets, industrial sites
Acute / Adult
bees - contact
Acute / Adult
bees - oral
1.5
3.6
9.26
0.39
1.5
42.94
9.06
4.74
1
2.4
9.26
0.26
1
28.62
9.06
3.16
< 0.4 / No
concern
>0.4 / High
risk
Forestry
Acute / Adult
bees - contact
Acute / Adult
bees - oral
Lucerne
April 2016
< 0.4 / No
concern
>0.4 / High
risk
65
Acute / Adult
bees - contact
Acute / Adult
bees - oral
0.6
1.44
9.26
0.16
0.6
17.17
9.06
1.89
1.5
3.6
9.26
0.39
1.5
42.94
9.06
4.74
< 0.4 / No
concern
>0.4 / High
risk
Barley grass control
Acute / Adult
bees - contact
Acute / Adult
bees - oral
< 0.4 / No
concern
>0.4 / High
risk
Acute effects on brood, acute oral effects and chronic effects on adults and brood
No assessment possible as no data provided on these toxicity endpoints
Conclusions for the bee risk assessment
Acute oral risks were below the level of concern for all use scenarios, but high contact risks for the uses on
barley grass and non-crop situations (industrial sites, stock yards). The following assumptions are made
regarding the potential exposure of bees to Para-Ken 250 Herbicide. Bees are not attracted to pine forests.
The application on Lucerne is during winter (when Lucerne is dormant) which will reduce the potential
exposure for bees. Likewise the application on non-crop situations will reduce the exposure to bees, which
are not likely to forage in industrial sites and/or around buildings. The staff consider that the application on
clover for seed production represent the highest potential exposure risk for bees. Therefore, the staff
consider that the Para-Ken 250 Herbicide must not be applied in clover crop intended for seed production.
6.8.5 Non-target arthropod risk assessment
There was no reliable data to conduct a quantitative risk assessment to non-target arthropods (LR50 and or
ER50). The staff conducted a search on relevant information about the effects of paraquat dichloride to nontarget arthropods but no data could be used to support a quantitative risk assessment. The staff consider
that the due to the properties and mode of action of paraquat dichloride the risks to non-target arthropods
can be considered below the level of concern.
April 2016
66
6.8. Summary and conclusions of the ecological risk assessment
6.8.1. Environmental fate and behaviour
Paraquat dichloride was shown to be very immobile in soil. Paraquat does not hydrolyse, does not
photodegrade in aqueous solutions, and is resistant to microbial degradation under aerobic and anaerobic
conditions. The primary route of environmental dissipation of paraquat is adsorption to biological materials
and soil clay particles. Due to the apparent adsorption strength of paraquat for soil clays, these bound
residues do not appear to be environmentally available. There was no desorption of paraquat from any of the
soils tested. Due to high biological toxicity to plants and animals prior to adsorption, paraquat is subject to
spray drift concerns. However, paraquat has extremely high adsorption coefficients, it is not expected to
volatilize once applied to the soil.
6.8.2.
Ecotoxicology
The EPA staff assessed the potential risk to be triggered by the use of Para-Ken 250 Herbicide according to
the GAP table and draft label recommendations.
Aquatic organisms
Acute risks were below the level of concern for fish and aquatic invertebrates. High acute risks were
observed for algae fior use scenarios and high risk for thretaned aquatic plant species at application rates
higher than 1.0 kg paraquat dichloride per hectare. Chronic risks were below the level of concern for aquatic
invertebrates, but high chornic risks were observed for threatened species at 1.5 kg paraquat dichloride per
hectare. No chronic data was available for fish. Risks to algae cannot be mitigated using mitigation
measures such as buffer zones. The modelling with AgDrift calculated a buffer zone larger than 254 meters
(largest buffer zone possible to calculate using AgDrift). Therefore, the staff consider that the risks of ParaKen 250 Herbicide to algae are not manageable.
Sediment organisms
Risk were below the level of concern for sediment dwelling organisms.
Soil organisms
April 2016
67
Risks were below the level of concern for earthworms in field and outside the crop area, including for
threatened species.
Non-target plants
Risk were below the level of concern for seedling emergence for all proposed uses. However, high risks
were identified for vegetative vigour for the uses on non-crop situations, barley grass control and forestry.
The following downwind buffer zones must be observed in order to protect non-crop plants from
unacceptable levels of spray drift from Para-Ken 250 Herbicide:
Non-crop situations (industrial sites, streets, etc.): 5 meters
Forestry: 30 meters
Barley grass control: 5 meters
For the protection of threatened native terrestrial plants the following advisory downwind buffer zones must
be observed:
Clover: 5 meters
Non-crop application (industrial sites, streets, etc.): 10 meters
Forestry: 50 meters
Lucerne: 5 meters
Barley grass control: 10 meters
Vertebrates
There were high acute and high chronic risks for all crops and bird types. There are no adequate mitigation
measures to protect birds from this potential risk.
Staff consider that for the applications of Para-Ken 250 Herbicide using knapsack for spot treatment in noncrop situations, such as the removal of weeds in industrial sites and streets will represent a lower potential
risk for birds.Therefore this use is considered acceptable by staff.
Bees and non target arthropods
Acute oral risks to bees were below the level of concern. High contact risk to bees were observed for all use
scenarios. Staff consider that the potential exposure to clover crops represent the highest risk to
bees.Therefore, the staff consider that the Para-Ken 250 Herbicide must not be applied in clover crop
intended for seed production.
Staff consider that due to the mode of action and properties of paraquat dichloride the risks to non-target
arthropods can be considered below the level of concern.
Overall conclusion for the environmental risk assessment
April 2016
68
Staff consider that the approval of Para-Ken 250 Herbicide as broadcast spray to clover, Lucerne, forestry
and barley grass control should be declined due to the unacceptable risks posed to algae and birds.
Staff consider that the application of Para-Ken 250 Herbicide as spot treatment (non wide-dispersive use) in
non-crop situations such as the application on streets and industrial sites the risks can be considered below
the level of concern for the environment.
April 2016
69
7. Controls
7.1.
Physical hazards controls
Apply the Approved Handler Controls (AH1, F4):
Yes
No
Apply the Tracking control (TR1):
Yes
No
7.2.
Toxicity controls
Exposure Thresholds
Table 5 Active ingredient(s) exposure thresholds
Active
Ingredient(s)
Acceptable Daily
Exposure (ADE) –
mg/kg bw/d
Potential Daily
Exposure (PDE)
– mg/kg bw/d
Tolerable
Exposure Limit
(TEL)
mg/L (water)
mg/kg (soil)
mg/m3 (air)
Workplace
Exposure
Standard (WES17)
Paraquat dichloride
Not set at this time
Not set at this time
Not set at this
time
WorkSafe New
Zealand has not set a
WES for paraquat
dichloride .
Table 6 Other component(s) exposure thresholds
Other component(s)
WES
Component D
WorkSafe New Zealand has set a WES value for
Component D of Para-Ken 250 Herbicide and Staff
consider this value to be applicable to Para-Ken 250
Herbicide
Apply the Approved Handler Controls - Highly Toxic Substances (AH1, T6):
Yes
No
Apply the Tracking Control - Highly Toxic Substances (TR1):
Yes
No
Other toxicity controls
Based on the human health risk assessment Staff were not able to identify any controls that would
sufficiently ensure that exposures are below acceptable levels.
7.3.
17
Ecotoxicity controls
http://www.business.govt.nz/worksafe/information-guidance/all-guidance-items/workplace-exposure-standards-and-biologicalexposure-indices/workplace-exposure-standards-and-biological-indices-2013.pdf
April 2016
70
Table 7 Active ingredient(s) maximum application rates
Active component
Maximum application rate18 (control code E2)
Paraquat dichloride
1.5 kg a.i./ha, 4 applications at 28 days interval
Apply the Approved Handler Controls- Highly ecotoxic substances (AH1, E7):
Yes
No
Apply the Tracking control- Highly ecotoxic substances (TR1):
Yes
No
Other ecotoxicity controls
Additional controls, under section 77A, are set for the application of of Para-Ken 250 Herbicide as spot
treatment using knapsack:
This substance must not be applied onto or into water.
The knapsack must have nozzles equipped to release coarse droplets to prevent spray drift
7.4.
Mixture hazard classification calculations for identification controls
Table 8 Cut-off values triggering HSNO classification and requiring identification controls on the label and/or Safety
Data Sheet (SDS)
HSNO Classification
Cut-off for label (% w/w)
Cut-off for SDS (% w/w)
6.1A, B, C, D
Any % of component that would
independently of any other
component cause the product to
classify
Any % that causes the product to
classify
6.1E aspiration
Any % of component that would
independently of any other
component cause the product to
classify
Any % of component that would
independently of any other
component cause the product to
classify
8.2, 8.3
Any % that causes the product to
classify as 8.2 and/or 8.3
Any % that causes the product to
classify
6.5A, 6.5B, 6.6A, 6.7A
0.1
0.1
6.6B
1
1
6.7B
1
0.1
6.8A, 6.8C
0.3
0.1
6.8B
3
0.1
6.9A, 6.9B
10
1
(required on the basis of §77a)
Table 9 List of components requiring identification
18
These regulations relate to the requirement to set an application rate for a class 9 substance that is to be sprayed or applied
to an area of land (or air or water) and for which an EEL has been set.
April 2016
71
Label
SDS
Paraquat dichloride
Paraquat dichloride
April 2016
72
References
Novis P (2015) New Zealand Freshwater and Brackish Diatom Types.
http://www.landcareresearch.co.nz/resources/identification/algae/diatoms
SANCO (2003) Review Report for the active substance paraquat. October 3, 2003.
United States Environmental Protection Agency (1997) Registration Eligibility Document (RED). Paraquat
Dichloride. August 1997.
April 2016