Paraquat - Protecting our way of life | EPA · 2019. 10. 14. · Hazard Classifications - Paraquat...

Paraquat reassessmentEPA Staff hearing presentation

11 SEPTEMBER 2019

Paraquat

• Broad-spectrum contact herbicide, fast-acting desiccant

• Used in a variety of crops for general weed management, and

desiccation of seed crops

• Only paraquat and diquat have group D mode of action

(Photosystem-I inhibition)

• Reportedly good for managing resistance (some resistance

has developed in black nightshade in kūmara crops)

• Rapidly and irreversibly adsorbs to soil (persistent, but not

biologically available)

• Seven affected approvals, 12 ACVM registered products

2

International status• No longer an approved active ingredient in the EU

• Banned in Brazil (currently in phase-out period)

• Registered in USA, with mitigation measures implemented

(currently in 15 year re-evaluation cycle, decision anticipated in

2020). Now requires specific training following special review

• PMRA published special review decision 2015. Registered in

Canada with closed delivery system (most recent registration in

2018)

• Under review in Australia (APVMA published human health

assessments in 2016)

• Burkina Faso has recommended PQ be listed in Annex III,

Rotterdam Convention

3

NZ regulatory history

• Deemed approval via Transfer process in 2005

• Para-ken application showed risks to both human health and the

environment were unacceptable in 2016 (declined)

• Grounds for reassessment were established citing the Para-ken

information as significant new information in July 2017

• Call for Information (CfI) open from 1 July 2017 – 30 August 2017

• Reassessment Application prepared and formally received on 25

February 2019

• Submission period open from 28 February 2019 – 30 April 2019

• Update Report made publicly available 26 August 2019

4

Approach to assessmentIterative approach, tailor-made for paraquat

• Para-ken assessment was modified and incorporated information from

Call for Information

• Outcomes from modelled scenarios used to inform subsequent

modelling

• Assessment presented in the application form was made available for

stakeholders to undertake refinement and make submission

• Stakeholder assessments evaluated

• Assessments finalised incorporating stakeholder submissions

5

Human health assessmentParaquat reassessment

Para-ken 250 Herbicide

Human Health Risk Assessment• A worst case scenario was modelled

- Dermal absorption defaults

- A max. application rate of 1500 g ai/ha

- Upward hand-held spraying

• Predicted exposure to operators during mixing, loading and

application were >>AOEL (even with full PPE incl. respiratory

protection).

• Predicted exposures of bystanders 8 metres away from the edge

of an application area were greater than the acceptable level and

buffer zones of 16 – 30 m were required.

7

Hazard Classifications - Paraquat

* Classifications reviewed and changed to be consistent with other regulators.

(The classification changes have no impact on our risk assessment.)

8

Hazard endpoint Classification (current)Classification

(Reassessment)*

Acute toxicity (oral) 6.1B 6.1C

Acute toxicity (dermal) 6.1B 6.1E

Acute toxicity (inhalation) 6.1A 6.1A

Skin irritation/corrosion 6.3A 6.3B

Eye irritation/corrosion 6.4A 6.4A

Target organ toxicity (oral) 6.9A 6.9A

Derivation of the AOEL

• The table compares the input parameters for deriving the AOEL for

Para-Ken and the Paraquat Reassessment application

UF: 10 for interspecies uncertainty; 10 for intraspecies

AOEL = [NOAEL x (percentage oral abs/100)]/ UF

9

Parameter Para-Ken 250 Paraquat

Reassessment

NOAEL (mg/kg bw/day) 0.45 0.56

Oral abs. used to set AOEL (%) 10 13

Uncertainty Factor (UF) 10 x 10 = 100 10 x 10 = 100

AOEL (mg/kg bw/day) 0.000450 0.000728

AOEL (after rounding) (mg/kg bw/day) 0.0005 0.0007

HH – Input Parameters

• Boom, 8 hr, 50 ha

10


Reassessment

Application rate (g ai/ha) 1500 600

Dermal abs. (%) - concentrate 6 0.4

Dermal abs. (%) - spray 30 0.4

AOEL (mg/kg bw/day) 0.0005 0.0007

RQ – Full PPE and max. respiratory

protection

108 0.98

HH – Input Parameters

• Knapsack: 8 hr, 1 ha

* Result taking into account update paper revision.

11


Reassessment

Paraquat

Revised

Modelling*

Application rate (g ai/ha) 1500 390 600

Dermal abs. (%) – conc. 6 0.4 0.4

Dermal abs. (%) - spray 30 0.4 0.4

AOEL (mg/kg bw/day) 0.0005 0.0007 0.0007

RQ – Full PPE and max.

respiratory protection

86 1.01 0.569

Human Health – Refined Risk Assessment

• Modelling utilised by EPA was deemed conservative relative to the likely

exposure - likely to overestimate the risk.

• Written rationale and data were presented by a submitter to indicate why

inhalation is not a relevant route of exposure.

• Data from several in vivo operator exposure studies demonstrated inhalation

following both boom and knapsack application methods is minimal.

Conclusion:

• PPE is not necessary to protect against respiratory exposure.

• Exposure estimates from revised modelling support the use of paraquat at an

application rate of 600 g ai/ha for boom and 600 g ai/ha with a knapsack.

12

Environmental assessmentParaquat reassessment

• Application made in November 2015, decided in April 2016

• Included application rates up to 1500 g paraquat/ha

• Environmental risk assessment carried out with information available

• Some study data were provided by the applicant

14Para-ken 250 Herbicide (APP202697)

Para-ken 250 Herbicide (APP202697)

• Other environmental fate and ecotoxicity endpoints were sourced from

1. EPA internal substance database

2. Other regulators reviews:

European Union: EC (2003). Review report for the active substance paraquat. Brussels, European Commission, Health & Consumer Protection Directorate-General

United States: US EPA (1997). R.E.D. Facts - Paraquat Dichloride

Canada: PMRA (2015). Special Review of Paraquat: Proposed Decision for Consultation. Ottawa, Pest Management Regulatory Agency

15

Paraquat properties

• Persistent in the environment (half-lives of 7- 8 years in field)

• Immobile in soil (lowest Koc of 15,473 mL/goc)

• Toxic to terrestrial plants (as expected for a herbicide)

• Not toxic to soil/sediment dwelling organisms, even at high rates

• High toxicity to algae and aquatic plants (as expected for a herbicide)

• High ecotoxicity to birds (acute and chronic)

• Ecotoxic to bees through oral and contact routes

16

Para-ken 250 Herbicide (APP202697)

• Risks to aquatic organisms (algae) greater than the level of concern with no

mitigation possible (buffer zone > 254 m)

• Risks to non target plants – managed by buffer zones

• Acute and chronic risks to birds – no mitigation possible

• Risks to bees – managed by controls to not apply to plants in flower

• No risks to soil and sediment-dwelling organisms

17

Application for import declined

Syngenta response to the call for information

• Provided a large dossier of paraquat-related information

• Provided a specific response relating to the aquatic and bird risk

assessments

18

Aquatic risk assessment

• Syngenta argued that the rapid sorption of paraquat to sediment

reduces the bioavailability (similar argument accepted by EFSA

in the context of diquat review)

• Provided an algae study in the presence of sediment

• EPA accepted this argument. Revised risk assessment at 600 g

ai/ha using the new algae value lead to reduced risks:

• 5 m ground based application

• 15 m aerial application

19

Bird risk assessment

Acute

• Syngenta provided a rationale for changing the acute endpoint used in the

Para-Ken report based on the deficiencies of the original study and provided

a better study

Chronic

• Syngenta suggested studies on which to base the chronic risk assessment

but did not provide a rationale why it should be used over the value in the

Para-ken assessment

20

Reassessment application (APP203301)

• Revised risk assessment for rates up to 600 g ai/ha concluded that risks to the

following list of organisms were acceptable with controls

Aquatic environment,

Soil organisms,

Non-target plants,

Bees,

Non-target arthropods

• Acute and chronic risks to birds were above the level of concern to both threatened

and non threatened species at all application rates except 100 g ai/ha

21

Syngenta submission – Bird risk assessment : acute endpoint

• Provided a rationale and supplied extra studies for changing the

toxicology endpoints22

Study Bird type Original EPA reassessment

application

Syngenta submission Final value used in the EPA

assessment

Johnson (1998) Mallard duck 54 54 54

Beavers and Fink (1979) ; Bobwhite quail Study was provided to the

EPA but not used

127 127

Hudson et al (1984) Mallard duck Study was not considered at

this time.

144 Disregarded study

Jopek (1981) ; Hen Study was not considered at

this time.


Clarke et al (1966) ; Hen Study was not considered at

this time.


Howe & Wright (1965) ; Hen Study was not considered at

this time.


Smalley (1973) ; Turkey Study was not considered at

this time.


Rationale for risk assessment endpoint

chosen

For the EPA tier 1

assessment, the lowest value

from a reliable study was

used.

HD5 value from Mineau et al

(2001)

Geometric mean value used in

accordance with the EFSA bird

risk assessment guidance

(EFSA 2009)

Endpoint chosen (mg/kg bw) 54 61.4 82

• Acute endpoint – EPA did not accept the approach suggested by Syngenta but, based on

some of the information provided, has been able to refine the endpoint

Syngenta submission – Bird risk assessment : chronic endpoint

• Provided a rationale and supplied extra studies for changing the

toxicology endpoints23• Chronic endpoint – EPA did accept the majority of Syngenta’s rationale for changing the

endpoint

Original EPA reassessment

application

Syngenta submission Final value used in the EPA assessment

Study Beavers and Fink (1982) Beavers and Fink (1982) Beavers and Fink (1982)

Species Mallard duck Mallard duck Mallard duck

NOEL mg/kg diet 30 30 30

Food consumption

(g/bird/day)

Unknown 159.9 124.8

Average weight of

birds (g/bird)

Unknown 1159.5 1159.5

Comment For the original EPA assessment

(EPA 2019), the EPA used the

value of 1.7 mg ion/kg bw/day

which came from the PMRA

(PMRA 2015). The PMRA have

used a conversion factor to convert

the units from mg/kg diet to mg/kg

bw/day

To convert long-term dietary

endpoints to a daily dietary dose

Syngenta have revised the

endpoint based on estimated food

consumption for female birds and

average body weights.

To convert long-term dietary endpoints to a

daily dietary dose the EPA has revised the

estimated NOEL using the estimated food

consumption of all birds and average body

weights.

Final endpoint

(mg/kg bw/day)

1.7 4.14 3.23

• Syngenta provided a refined acute and chronic risk assessment

based on European use scenarios at 600 g ai/ha

• Stale seedbeds

• Orchards

• EPA has reviewed these risk assessments

• EPA has used the information in these risk assessments with the

addition of the revised endpoints to determine the risks for New

Zealand use patterns at 600 g ai/ha

24

Syngenta submission – Bird risk assessment : scenarios

Bird risk assessment – overall conclusions

25

UseApplication rate (g ai/ha)

Bird species considered

Acute/chronic risk assessment

Risks to non-threatened bird species

Risks to threatened bird species

Pre-emergence use 600

InsectivorousAcute < LOC < LOC

Chronic > LOC (1.5 times) > LOC (3 times)

OmnivorousAcute < LOC < LOC

Chronic > LOC(1.5 times) > LOC (3 times)

GranivorousAcute < LOC < LOC


Lucerne 600







Clover desiccant use

400


Chronic < LOC > LOC (2 times)





• Acute risks are below the level of concern in all cases

• Chronic risks are :

• above the level of concern in all cases for threatened species

• above the level of concern in pre-emergence and Lucerne scenarios, below the level of concern in clover desiccant

Cultural assessmentParaquat reassessment

Cultural risk assessmentApplication form

• Cultural risk assessment presented in Appendix E of the application

form

• Persistence of paraquat in soil, and waterways (sediment) – may

raise cultural concerns about contamination of Papatūānuku and Te

Marae o Maru

• Risks to birds were outstanding in the environmental risk

assessment, and are of concern to Māori

• Supportive of proposal to revoke carcinogen, mutagen, reproductive

toxicant (CMR) approvals

• Supportive of proposed hand-held prohibition and closed-cab

restrictions to protect taha hauora (human health and well-being)

27

Cultural risk assessmentUpdate report

• Persistence of paraquat in soil, and waterways (sediment) –

may raise cultural concerns about contamination of Papatūānuku

and Te Marae o Maru

• Revised environmental assessment concludes that risks to birds

are still outstanding – of concern to Māori

• Supportive of proposal to revoke CMR approvals

• Revised human health risk assessment indicates that cab-less

machinery and hand-held application are not likely to generate

significant concerns regarding taha hauora

28

Kūmara

• Market Access Solutionz: there is significant cultural benefit in

allowing multiple applications of paraquat

• Difficult to reconcile the use of paraquat on kūmara, a taonga

vegetable, from a tikanga perspective

• Not consistent with the practice of kaitiakitanga and the

relationship of Māori with Papatūānuku

29

Economics and benefits assessmentsParaquat reassessment

Summary

• Sapere produced the economic benefits assessment, and will

make a presentation at this hearing

• The contribution of paraquat to GDP is estimated to be between

$39 million and $75 million annually

• Restricting the application rate of paraquat to:

• 400 g ai/ha would put up to $25 million in GDP at risk

annually (33% of paraquat value);

• 600 g ai/ha would put up to $0.14 million in GDP at risk

annually (0.35% of paraquat value).

31

Weigh-up and risk mitigation measuresParaquat reassessment

Weighing up risks and benefits

• Benefits measured by contribution to GDP

• Quantitative values assigned qualitative descriptors in order to

compare to risks

• Used to determine application rate restriction: 400 g ai/ha was

thought to pose low risk, while offering medium-high benefit

• Submitters were explicitly invited to comment on our weigh-up and

risk aversion – no submissions addressed this

• Proposed prohibition of hand-held use, agricultural restriction,

revocation of CMR and “no-use” approvals – no benefit offered

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Hazard Classifications – Paraquat alternatives34

Classification of representative formulation

Active ingredient Physical

hazardsHuman health hazards Environmental hazards

Paraquat(eg HSR000828 - Gramoxone)

6.1A, 6.3A, 6.4A, 6.9A 9.1A, 9.3B, 9.4B

Glyphosate(eg HSR000227 - AGPRO Glyphosate 360)

6.1D, 6.4A 9.1B

Glufosinate(eg HSR100096 - Nirvana)

3.1D 6.1E, 6.4A, 6.8B, 6.9A 9.1D, 9.2A

Amitrole(eg HSR000505 – Chemagro Simdole SDA)

6.1E, 6.4A, 6.8B, 6.9A 9.1B, 9.2A

Diquat(eg HSR000446 – Dy-Quat 200)

8.1A 6.1C, 6.3A, 6.9A 9.1A, 9.3C

Terbuthylazine(eg HSR100964 – Timberwolf 900 WG)

6.1D 9.1A, 9.2A, 9.3B, 9.3C

Submissions

• Want to ban PQ outright (2);

• Support PQ restrictions, ultimately want PQ banned (3);

• No indication of position in regard to proposals (1);

• General support of retaining PQ with no indication of position in regard to controls proposed in the application form (3)

• General support of PQ, mostly in-line with controls proposed in the application form (3);

• Support re-approving PQ, but opposed to the additional controls proposed in the application form (6).

35

Notable controls we have proposed

Application form Update Report

Revoke CMR approvals

Revoke “no-use” approvals

Impurity specification control

Requirement for emetic and stenching agent

Prohibit hand-held uses

Product stewardship programme

Label statements

Max. app. rate 400 g ai/ha, 1x app. per year

Agricultural use only





Hand-held restriction in WorkSafe’s jurisdiction

Responsible handling information

Label statements

Max. app. rate 600 g ai/ha, some flexibility

Agricultural use only. Biosecurity use by permission

Responsible Handling Information Formerly Product Stewardship Programme

• Addresses concerns with end-user compliance following reassessment

• Examples may include website/documents/videos/leaflets/infograph

• Similar resources exist for overseas jurisdictions

• Interim accompanying information

• How to keep the environment safe (while working safely)

• Contains info from label, SDS, and more

• Regulatory requirements

• No longer proposing to require record (declaration) of understanding

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Label statements


DO NOT apply when wind speeds are less than 3 kph or more than 20 kph as measured at the application site.

Do not transfer this product into food or drinks containers, or into unlabelled containers.

To reduce runoff from treated areas into aquatic habitats avoid application to areas with a moderate to steep slope, compacted soil, or clay.

Avoid application when heavy rain is forecast.

DO NOT apply when wind speeds are less than 3 km/h or more than 20 km/h as measured at the application site.

Do not transfer this product into food or drinks containers, or into unlabelled containers.

Application rate restrictions


Maximum application rate: 400 g ai/ha

One application per year

Puts up to $17 m GDP at risk (29% of PQ value)

Puts up to $25 m GDP at risk (33% of PQ value)

Outstanding risks to birds considered to be outweighed by the benefits of PQ use

Benefits offered by 600 g ai/ha not considered to outweigh risks to birds

Maximum single application rate: 600 g ai/ha

Maximum annual application rate: 600 g ai/ha

Puts up to $0.14 m GDP at risk (0.35% of PQ value)

Risks to birds still outstanding, but less than previously thought for 400 g ai/ha, and are still outweighed by the benefits of PQ use

Annual application rate allows end-users to split the acceptable 600 g ai/ha over multiple applications

Associated buffer zones are up to 5 m for ground-based, up to 100 m for aerial

Agricultural use restrictions


Restricted to agricultural use only

Biosecurity use not considered

Intended to include forestry

Restricted to agricultural and biosecurity use only

Biosecurity use to require a permission under s 95A

Not intended to include forestry, intended to include ornamental horticulture

No evidence of significant forestry use (submissions, Agcarm report)

Label rates for forestry are 1000 g ai/ha

Conclusions41





Responsible handling information

Hand-held restriction in WorkSafe’s jurisdiction

Label statements

Max. app. rate 600 g ai/ha, some flexibility

Agricultural use only. Biosecurity use by permission

• Up to 600 g ai/ha, with consideration

of the prescribed and additional

controls, the residual risks posed by

paraquat are outweighed by the

benefits offered

• Risks to human health are

manageable up to this rate

• Risks to birds are still outstanding

• Restriction of paraquat to 600 g ai/ha

puts up to $0.14 m GDP at risk

(0.35% of PQ value)

• The persistence of paraquat is of

some concern, though the strong

adsorption to soil is noted

For more information contact:

General enquiries

Phone +64 4 916 2426 Fax +64 4 914 0433

[email protected]

Paraquat - Protecting our way of life | EPA · 2019. 10. 14. · Hazard Classifications - Paraquat...

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