EPA STAFF EVALUATION AND REVIEW REPORT
Application for the modified reassessment of Callisto (Marketed under Tenacity)
APP202063 February 2016
www.epa.govt.nz 2
Application for the modified reassessment of Callisto (APP202063)
Overview
Application Code APP202063
Application Type To modify an existing approval for a hazardous substance under Section 63A of the Hazardous Substances and New Organisms Act 1996 (“the Act”)
Application Sub-Type Modified reassessment – externally generated
Applicant Syngenta Crop Protection Limited
To extend the use of the registered product Callisto to turf, the Purpose of the application product is to be marketed under the name Tenacity Turf Herbicide
Approvals to be amended HSR002475 – Callisto
Date Application Received 13 April 2015
Submission Period 28 April 2015 – 10 June 2015
Submissions received Moreen Taylor
Te Rūnanga o Ngāi Tahu (Ngāi Tahu)
Bay of Plenty Regional Council
Hearing date 1 March 2016
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Application for the modified reassessment of Callisto (APP202063)
Table of Contents
List of Tables ...... 4
1. Background ...... 6
2. Process, consultation and notification ...... 6
3. Control to be reassessed ...... 7
4. Submissions ...... 7
5. Staff response to the submissions ...... 8
6. Risk and benefit assessment ...... 8
Assessment of risks to human health and the environment ...... 9 Overall assessment of the risk and the benefits ...... 13 7. Controls ...... 13
Proposed amendment...... 14 Additional controls and variation of controls to manage risk associated with the new use ...... 14 8. Overall evaluation and recommendation ...... 15
Appendix A: Proposed New Controls ...... 17
Appendix B: Mammalian toxicology ...... 23
Appendix C: Ecotoxicology ...... 29
Appendix D: Quantitative human health risk assessment ...... 43
Worker risk assessment...... 46 Bystander risk assessment ...... 48 Summary and conclusions of the human health risk assessment ...... 49 Appendix E: Quantitative ecological risk assessment ...... 50
Environmental fate data ...... 50 Summary of ecotoxicological data on mesotrione and its metabolites ...... 54 Aquatic risk assessment ...... 61 Terrestrial risk assessment ...... 67 Summary and conclusions of the ecological risk assessment ...... 79
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List of Tables
Table 1: Hazard classification for Callisto ...... 8 Table 2: Proposed new controls for Callisto ...... 17 Table 3: Phototoxicity studies ...... 23 Table 4: Immunotoxicity studies ...... 24 Table 5: Endocrine disrupting properties ...... 26 Table 6: Aquatic plants acute toxicity (Freshwater species) - effects of the metabolite R44276 (AMBA) ...... 29 Table 7: Aquatic plants acute toxicity (Freshwater species) – effects of the metabolite R169649 (MNBA) ...... 31 Table 8: Aquatic plants acute toxicity (Freshwater species) – effects of the metabolite SYN546974 .. 33 Table 9: Terrestrial plants bioassay – effects of ZA1296 (mesotrione) and metabolites AMBA and MNBA ...... 35 Table 10: Terrestrial plants – semi field studies...... 37 Table 11: Transferable turf residues ...... 43 Table 12: existing AOEL for mesotrione ...... 46 Table 13: The derivation of dermal absorption value in humans ...... 46 Table 14: Output of human worker (operator) mixing, loading and application exposure modelling.... 47 Table 15: Re-entry exposure modelling ...... 48 Table 16: Exposure scenario ...... 49 Table 17: Estimated exposure of 15 kg toddler ...... 49 Table 18: Summary of environmental fate data on mesotrione and its metabolites – Values in bold are used for the risk assessment ...... 50 Table 19: Summary of ecotoxicological data on mesotrione and its metabolites – Values in bold are used for the risk assessment ...... 54 Table 20: Reference documents for environmental exposure and risk assessments ...... 58 Table 21: Level of concern ...... 62 Table 22: The parameters used in GENEEC2 modelling ...... 62 Table 23: Acute risk quotients derived from the GENEEC2 model and toxicity data ...... 64 Table 24 Chronic risk quotients derived from the GENEEC2 model and toxicity data ...... 65 Table 25: Input parameters for Sci-Grow analysis and resulting PEC values ...... 66 Table 26: Levels of concern ...... 67 Table 27: Acute in-field TER value for earthworms ...... 69 Table 28: Acute off-field TER value for earthworms ...... 69 Table 29: Basic drift values for 2 applications...... 69 Table 30: RQ value for non-target plant ...... 70 Table 31: Exposure of birds for acute screening assessment ...... 72 Table 32: Exposure of birds for reproduction screening assessment ...... 73 Table 33: Measures of exposure and toxicity used in the reproduction assessment ...... 73
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Application for the modified reassessment of Callisto (APP202063)
Table 34: TER values for acute dietary and reproductive risk assessment – Screening assessment . 74 Table 35: EEC are calculated for this assessment ...... 76 Table 36: Risk to bees ...... 77 Table 37: In-field HQ values for Typhlodromus pyri and Aphidius rhopalosiphi ...... 78 Table 38: Off-field HQ values for Typhlodromus pyri and Aphidius rhopalosiphi ...... 79
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Application for the modified reassessment of Callisto (APP202063)
1. Background
Callisto was approved in April 2006 for use as a herbicide for the selective control of a wide range of broadleaf weeds in grain and silage maize. It contains 480 g/L mesotrione as the active ingredient.
The applicant has applied for a modified reassessment of Callisto to allow an increase in the maximum application rate and frequency of applications. This will allow it to be used on turf. This will be marketed as Tenacity turf herbicide. To remain consistent throughout this document, this substance will be referred to as “Callisto.”
Specifically, the applicant wishes to remove the modification to the E2 control:
The following application rate is set for Callisto: 450 mL product (290 g mesotrione)/ha in maize, once a year.
and replace it with a modification which increases the application rate to 600 mL product (387 g mesotrione)/ha, twice per year and to allow it to be used on turf. 2. Process, consultation and notification
Grounds for a modified reassessment were granted by a Decision-making Committee of the EPA on 5 July 2013.
The application for a modified reassessment was lodged pursuant to section 63A of the Act and was formally received on 13 April 2015.
The Minister for the Environment was advised of the application on 28 April 2015.
The Ministry for the Environment, WorkSafe New Zealand, the Ministry of Health, the Department of Conservation and the Agricultural Compounds and Veterinary Medicines (ACVM) group of the Ministry of Primary Industries were notified of the application and the submission period. No comments were received.
The application was publicly notified in accordance with section 53 of the Act. The application was open for submissions from 28 April 2015 until 10 June 2015.
Three submissions were received. Te Runanga o Ngāi Tahu indicated that they would like to be heard in support of their submission but subsequently withdrew their request to be heard.
The timeframe for consideration of the application was waived under Section 59 of the Act to obtain further information from the applicant.
As a hearing is not required for this application, a teleconference between the decision making committee will be held on 1 March 2016 to consider and decide the application.
In preparing this report, the following documents were taken into account:
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the application form, including the confidential material submitted by the applicant; the original application and associated documents; the submissions; and other available information. 3. Control to be reassessed
This modified reassessment proposes to delete the variation in the E2 control and replace it with a variation that allows a maximum application rate of to 600 mL product (387 g mesotrione)/ha, twice per year. Further, the application rate will be suitable for turf in addition to maize.
As the changes proposes a new use at a higher application rate, a quantitative risk assessment was completed by staff of the EPA. 4. Submissions
Three submissions were received from:
Moreen Taylor Te Rūnanga o Ngāi Tahu, and The Bay of Plenty Regional Council
Moreen Taylor and Te Rūnanga o Ngāi Tahu opposed the proposed change of controls and the Bay of Plenty Regional Council did not either support or oppose the proposed change. The full submissions are available from the EPA website1.
Moreen Taylor opposed the proposed changes as there are still environmental and human health risks associated with the product. She raised concerns about atrazine and aerial application of all hazardous substances, but considers ground-based application methods acceptable.
Te Rūnanga o Ngāi Tahu opposed the proposed changes on the grounds of inadequate consultation and information, specifically that much of the information regarding the substances, including the information regarding consultation with Maori, had not been updated since the initial application in 2006. They note that the risk of the new application appears to be low. They had concerns about the exposure to applicators if the substance was applied by non- certified applicators, spray drift, aquatic risks and risks to native species.
The Bay of Plenty Regional Council do not support or oppose the proposed changes, however they don’t believe it is appropriate for the EPA to require submitters to contact the applicant directly for more information after their request for information to the applicant was not
1 http://www.epa.govt.nz/search-databases/Pages/applications-details.aspx?appID=APP202063# (Click on the tag “Documents” of the webpage). For future reference, the ‘keyword’ reference number for this application is APP202323.
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answered. They criticised the risk assessment in the application form and recommend a more detailed risk assessment to guide the setting of controls for the new use. 5. Staff response to the submissions
We note that this application is not for aerial application of Callisto. In respect to Moreen Taylor’s concerns about the chemical atrazine, which is unrelated to this application, we also note that atrazine is the 16th priority out of 33 active ingredients on the chief executive-initiated reassessment program.
We consider that the application met the requirements for formal receipt in that all aspects of the application form were completed. While the information provided by the applicant does not represent a significant update of the assessment of the risks, costs and benefits of Callisto’s new use with respect to the kaitiaki relationship of Māori, and their culture, to the environment, we note that information is available for an assessment of the potential risks to Māori culture and values. We note that the Decision-making committee is able to request further information if they consider that they do not have sufficient information to make a decision on this application.
Some of the information that Te Rūnanga o Ngāi Tahu and the Bay of Plenty Regional Council consider should have been released is commercially sensitive information that has been withheld from public release under section 57 of the Act. The full composition of Callisto, as well as data regarding the physical and toxicological properties of the active ingredient and Calllisto are trade secrets and their public disclosure could prejudice the commercial position of the applicant.
We have completed a new risk assessment and proposed controls to manage the new risks including controls relating to spray drift. 6. Risk and benefit assessment
We determined that the hazard classification of Callisto had not changed and this is reproduced below: Table 1: Hazard classification for Callisto Hazard Endpoint Classification
Eye irritancy 6.4A Target organ systemic toxicity 6.9A (O) Aquatic ecotoxicity 9.1A Soil ecotoxicity 9.2A Application equipment and parameters for use on turf are quite different exposures to existing uses of Callisto. Therefore a quantitative risk assessment of both human health and the environment was performed using the higher rate and use pattern.
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Assessment of risks to human health and the environment
Our quantitative human health and environmental risk assessments are set out in Appendices B and C respectively.
Human health risk assessment The quantitative human health risk assessment concluded that, for the proposed new use patterns, the levels of exposure for re-entry workers and bystanders were all within acceptable levels (i.e. below the Acceptable Operator Exposure Level, AOEL). The risk to workers during mixing, loading and application were above an acceptable level, but could be reduced to an acceptable level if full PPE was worn during mixing, loading and application.
Environmental risk assessment A quantitative environmental exposure risk assessment indicated that the active ingredient, mesotrione, is not considered to be persistent and does not bioaccumilate. The risk assessment showed that the risks to fish, aquatic invertebrates and algae from exposure to Callisto were below the level of concern, however, the risks to aquatic plants from exposure to Callisto was above the level of concern. Risks of groundwater contamination with Callisto were below the level of concern.
The terrestrial assessment of the proposed use of Callisto indicated that the exposure of earthworms or birds to Callisto are below the level of concern. The exposure of non-target plants is above the level of concern and a downwind buffer zone of 15 m is necessary to reduce the exposure of non-target plants to acceptable levels of spray drift. An advisory buffer zone of 275 m should serve as guidance for the applicators regarding the risks to threatened native plant species. The risks to bees and other beneficial insects is above the level of concern but can be mitigated by restrictions and controls.
Therefore the risks associated with aquatic plants, non-target plants, threatened native plant species and bees and beneficial insects can be adequately managed using appropriate controls. Relationship of Māori to the Environment
Kupu arataki (Context) The potential effects of Callisto on the relationship of Māori to the environment have been assessed in accordance with sections 5(b), 6(d) and 8 of the Act. Under these sections all persons exercising functions, powers and duties under this Act shall: Recognise and provide for the maintenance and enhancement of people and communities to provide for their cultural well- being, and; take into account the relationship of Māori and their culture and traditions with their ancestral lands, water, taonga and the principles of the Treaty of Waitangi (Te Tiriti o Waitangi).
Callisto triggers a number of hazardous properties giving rise to the potential for cultural risk e.g. aquatic ecotoxicity. Cultural risk includes any negative impacts to treasured flora and fauna
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species, the environment, and the general health and well-being of individuals and the community.
In general, the introduction and use of hazardous substances has the potential to inhibit the ability of Māori to fulfil their role as kaitiaki. This is particularly relevant when considering the guardianship of land and waterways given the ecotoxic nature of Callisto to Te Marae o Tāne (terrestrial ecosystems) and Te Marae o Tangaroa (freshwater and marine ecosystems), in particular species associated with mahinga kai (food resources), rongoā (medicine) and pūeru (textiles) as well as other cultural and historical associations.
Mahinga kai, rongoā me pūeru (Food resources, medicine and textiles) With respect to Te Marae o Tāne, there is the possibility of acute risk to culturally significant terrestrial plants used for food, medicine or weaving, for example, pūhā (sow thistle), kawakawa (pepper tree), harakeke (flax), rarauhe (bracken fern), pōhata (wild turnip), raupeti (black nightshade), poroporo (kangaroo apple), koromiko (NZ veronica), kopakopa (NZ plantain), paewhenua (common dock) and raupō (bulrush). With respect to Te Marae o Tangaroa, there is potential for Callisto to enter waterways and adversely affect culturally significant aquatic plants, in particular kowhitiwhiti (watercress). Kowhitiwhiti and pūhā are iconic Māori vegetables. The importance of harakeke to Māori in terms of textiles, equipment, art and ornamentation does not require any elaboration.
It is anticipated that applications of Callisto will occur on public and private land where access to sprayed areas is controlled. However, there may be potential for cross boundary spray drift to contaminate taonga species within adjoining land and waterways where access may be less restricted. This includes plants growing in publicly accessible places such as road reserves, parks and the margins of watercourses where taonga species may be gathered.
Hazardous substances can engender both direct and indirect impacts on Māori interests. Direct impacts are the positive or adverse effects on culturally significant receptors such as taonga species. Indirect impacts are the consequential effects, that is, how such impacts affect the ability of Māori to express their culture, in particular customary practices and usages associated with the affected taonga species.
For example, spray drift on kawakawa plants would render them unserviceable for a range of traditional uses including rongoā (medicine), pare kawakawa (head wreaths for tangihanga i.e. funerals), kawanga whare (house opening ceremony), whakainu waka (canoe launching rituals), tūā rite (naming and tapu removal rituals for newborns and mothers) and tohi rite (dedication of children to success and wellbeing).
The importance to Māori of ensuring that taonga species flourish cannot be overstated historically or contemporarily. In former times, mahinga kai, rongoā and pūeru were critical for sustaining Māori communities and whānau. Wild vegetables formed a very important part of the food supply. Taonga species remain essential for continuing customary practices and meeting cultural obligations, especially in respect of showing manaaki (hospitality) to guests on the
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marae, providing whānau with traditional kai, healing people using age-old remedies, and performing rituals in accordance with proper method and material.
Rarauhe (bracken fern) has special significance to Māori. In pre-contact times, rarauhe was the most important wild vegetable – its starchy underground stems and tender young shoots were a staple food. Survival of Māori in Aotearoa depended on rarauhe when cultivated crops of kūmara (sweet potato), taro (arum) and uwhi (yam) failed.
Rarauhe is also deeply symbolic. Along with other fern species it is used as a metaphor for leadership, succession, natural life cycles and intergenerational sustainability. For example, the whakataukī or proverbial saying ‘Mate atu he tētēkura, ara mai he tētēkura’ (As one fern frond dies another rises to take its place) encompasses these notions. Similarly, the young curled shoots of rarauhe emerging from the ground are sometimes generically referred to as ‘pikopiko’ (not to confuse with pikopiko the shield fern), a term commonly used as a metaphor for the younger or next generation of people. Such idioms are often used to embellish whaikōrero (speeches) and literature.
Ngā wai koiora (Aquatic habitats) Māori are concerned about any risk to aquatic habitats arising from Callisto entering waterways and adversely affecting kekakeka (duckweed) and other aquatic plants, which are a food source for culturally significant species pārera (grey duck), kuruwhengu (Australasian shoveler duck), pāpango (NZ scaup), pāteke (brown teal), pūweto (spotless crake), rakiraki (mallard duck), kuihi (Canada goose) and kakīānau (black swan).
Aquatic plants, including kowhitiwhiti, offer a habitat and protection for small fish and invertebrates such as kōura / kēwai (freshwater crayfish) and kōuraura (shrimp). A Māori term for freshwater plants that afford shelter in this manner is ‘petipeti’ and the fish life it protects is known as ‘kai moe petipeti’ or food that sleeps in water weed. Māori understand the role petipeti plays in providing a nursery and protective cover for aquatic organisms, and there is potential for Callisto to put these functions at risk.
Ngā One (Soils) It is noted that Callisto is classified as being ecotoxic to soil environments. This is concerning to Māori due to the potential for Callisto to directly poison or defile Papatūānuku (earth mother), wife of Ranginui (sky father), from whom all living things originate. Papatūānuku is central to Māori creation stories and represents many things to Māori. Whenua (land) and soils (one), which provide a basis for life, are personified in Papatūānuku and are fundamentally important to Māori identity. The inextricable link between Māori and whenua is reflected in the term ‘tangata whenua’ meaning people of the land. Whenua provides a tūrangawaewae – a place where a person can stand and feel they belong. Whenua also means placenta. Humans are born of Papatūānuku, are sustained by her placenta (the land) and return to her upon death. Similarly, it is Māori tradition following childbirth to return the placenta to Papatūānuku by
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burying it in a significant place. Māori are concerned to avoid compromising these cultural associations in relation to Callisto.
Any adverse impacts on soil environments, including potential risks to life forms such as worms and naturally occurring bacteria, would be regarded as culturally undesirable. This is particularly the case in respect of noke/toke (earthworms) which are taonga species. Noke/toke are important to Māori because they:
Are a source of food for culturally significant species e.g. tarāponga (red billed gull), kotare (kingfisher) and pūtangitangi (paradise shelduck)
Are used in traditional fishing methods e.g. toitoi tuna (eel bobbing)
Are a part of the Māori cosmogeny e.g. stories concerning Māui and the mortality of humans
Have geographical significance through incorporation into place names e.g. Te Tai Tokerau (Northland).
Taha hauora (Human health) Callisto is classified as an eye irritant and toxic to human target organs and systems. For these reasons, Callisto poses a level of risk to taha hauora (human health) particularly the dimensions of taha wairua (spiritual health and well-being obtained through the maintenance of a balance with nature and the protection of mauri) and taha tinana (physical health and well- being).
Exposure to Callisto may inhibit taha whānaunga – the responsibility to belong, care for and share in the collective, including relationships and social cohesion. There is a risk that using this substance may compromise the ability of people to protect co-workers and others where it is being used unless appropriate practices and precautions are applied. Ensuring the collective welfare and fostering a sense of well-being and safety amongst all involved is important for maintaining taha whānaunga.
Ētahi atu mea (Other matters) Aside from the foregoing issues, Callisto does not raise significant concerns in relation to taonga species of ika (fish), manu (birds) and Te Aitanga Pēpeke (insects).
It should be noted that this is a modified reassessment to change the use pattern of a substance that has already been approved for use. However a fuller assessment of the impact of Māori interests has been taken in this case as Māori like to take a full world view of the environment and the hazardous substances within it.
Some of the foregoing risks to environmental and human health can be mitigated by applying controls that: specify maximum rates and frequency of spray applications; limit use to ground based application methods; require approved handler status; stipulate use of PPE; reduce effects of spray drift by requiring nozzles to spay coarse droplets; apply downwind buffer zones
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including separation distances to waterways and non-target plants, and; require certain controls, limations and restrictions to be displayed on labels.
Controlling a wide range of broadleaf and grass weeds in turf will produce economic, recreational and community benefits for those working in, or using, turf based activities, many of whom are Māori.
Kupu whakatepe (Conclusion) Based on the information provided, including the use pattern and the controls proposed to be assigned to Callisto, the potential risks to Māori culture or traditional relationships with the environment should be minimised.
If Callisto is applied in the prescribed manner it is considered that it is not likely to breach the principles of the Treaty of Waitangi, particularly the principle of active protection. Benefit Assessment
The applicant has assessed the benefit of extending the use of Callisto to include turf, specifically cool season turf. A calculation performed by the applicant suggests that there is approximately 45,000 hectares of this sort of turf that will require turf management in New Zealand.
Callisto can be used to control both broad leaf weeds and grass weeds. Using one herbicide on two different weed types decreases the number of different herbicides that need to be applied, thus reducing the time and expense of application.
Turfs are used for sport and recreational activities (just under half of the above calculated turf areas are schools) and therefore high quality of turf without irregularities (such as weeds or holes in the turf surface) will reduce the incident of injuries to those who use it.
Callisto will be a viable and useful new herbicide for turf; particularly as it provides an alternative mode of action, which is important for preventing herbicide resistance in weeds. It also has a lower toxicity than other products on the market. New Zealand’s international obligations We are satisfied that the modified use of Callisto will not impact any of New Zealand’s international obligations. Overall assessment of the risk and the benefits
The proposed change in the use will result in increased risk to people and the environment, and the relationship of Maori with the environment, which can be mitigated to negligible by additional controls. No other increase in risk was identified for society, culture, or the economy. However benefits identified are associated with the use of a different herbicide for the management of turf. 7. Controls
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The initial decision on Callisto set controls to manage the risk associated with the use proposed at that time. Based on the risk assessment for the proposed new use, it is considered that the following additions and variations to the controls should be applied to Callisto.
Proposed amendment
The proposed amendment is to change the E2 application rate from:
The following application rate is set for Callisto: 450 mL product (290 g mesotrione)/ha in maize, once a year.
to
The following application rate is set for this substance:
the substance must not be applied at rates exceeding 600 mL of formulated product/ha per application (equivalent to 387 g mesotrione /ha); and the substance must not be applied to the same area more than two times in any 330 day period; and an interval of at least 14 full days must be observed before the substance is reapplied to the same area.
Our risk assessment showed that, there are additional risks associated with this proposed use. As these risks can be managed, then the proposed new application rate is acceptable.
Additional controls and variation of controls to manage risk associated with the new use
We propose the following controls to manage those risks that arise when Callisto is applied to turf.
As the amount of active ingredient to be applied per hectare has increased, the amount of active ingredient that users will be exposed to has also increased. To manage this, we propose the following variation to the T5 control regarding PPE:
The following subclause is added after subclause (1)(b) of regulation 8:
(1)(c ) A person handling (mix, load or apply) this substance must ensure minimum requirements for PPE are worn: Coveralls Shoes Socks Gloves Hood/Visor
We also note that while our risk assessment did not see a risk in worker reentry directly after application, it is good practice to wait until the substance has dried before allowing reentry into
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an area which has been sprayed. It is expected that this good practice will be used with the new application rate.
As the new use pattern includes applying more Callisto per hectare of land, the risk of harm to aquatic non-target plants and terrestrial non-target plants has increased. To mitigate these risks, the following three controls have been proposed:
This substance must be applied with nozzles equipped to provide a coarse spray2 This substance must not be applied within ten metres3 of a downwind4 water body5 This substance must not be applied within 15 metres6 of downwind non-target plants
These controls are to reduce the effects of spray drift. The control relating to coarse spray will increase the size of the droplets of the substance when applied and therefore the droplets will not travel as far as a finer spray mist. The two controls relating to buffer zones will give an appropriate amount of space between application of the substance and non-target plants or water bodies. Our quantitative risk assessment also identified that a 275 m downwind buffer zone would mitigate the risks relating to threatened native plant species. The Decision-making committee may wish to consider the addition of this information as a label control.
In order to communicate these controls relating to the new use pattern effectively, statements about the controls, limitations and restrictions should be clearly displayed on the label. Therefore we have proposed adding a new labelling control to Calliso. The proposed wording is outlined in Appendix A. 8. Overall evaluation and recommendation
The proposed use of Callisto on turf, with a higher application rate, does raise some additional risks compared with the previous use. However, we consider that these additional risks can be adequately managed using the controls outlined in Appendix A.
In addition, the benefits of using Callisto on turf will outweigh the risks when used with appropriate controls.
2 A coarse quality spray according to the American Society of Agricultural & Biological Engineers (ASABE) droplet size classification scheme.
3 This distance is the distance between the edge of the application area closest to the water body and the edge of the water in the water body closest to the application area.
4 Downwind refers to a location in a direction to where the wind blows away from the application area.
5 A water body includes modified water courses such as reservoirs, irrigation canals, water-supply races, canals for the supply of water for electricity generation or farm drainage canals, as well as natural water bodies.
6 This distance is the distance between the edge of the application area closest to the non-target plants and the non-target plants.
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Therefore we recommend that the Committee accepts the proposal to allow the use of Callisto on turf with the associated controls that will mitigate the risk associated with the proposed new use.
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Appendix A: Proposed New Controls
The following are the controls for Callisto (HSR002475) with the proposed new controls added and highlighted.
Please refer to the Hazardous Substances Regulations and the modifications listed below for the requirements of each control. The regulations can be found on the New Zealand Legislation website http://www.legislation.co.nz.
Table 2: Proposed new controls for Callisto
Hazardous Substances (Classes 6, 8, and 9 Controls) Regulations 2001
Code Regulation Description Variation
T2 Regs 29, 30 Controlling exposure in places of work A WES is adopted for the following through the setting of WESs. component of Callisto: Component G (vapour and mist) = TWA Ceiling 50 ppm (127 mg/m3)
T3 Regs 5(1), 6 Requirements for keeping records of use
T4 Reg 7 Requirements for equipment used to handle substances
T5 Reg 8 Requirements for protective clothing The following subclause are added and equipment after subclause (1)(b) of regulation 8: (1)(c) A person handling (mix, load or apply) this substance must ensure minimum requirements for PPE are worn: (a) Coveralls (b) Shoes (c) Socks (d) Gloves (e) Hood/Visor
T7 Reg 10 Restrictions on the carriage of toxic or (f) The maximum quantity of this corrosive substances on passenger substance that can be carried service vehicles on a passenger service vehicle is 1.0 L per package
E1 Regs 32 – 45 Limiting exposure to ecotoxic The following EELs are set for substances through the setting of mesotrione: EELs EELsurface deposition = 0.0037 mg/m2 for mesotrione in the terrestrial environment.
EELsoil = 0.0001 mg/kg dw soil.
EELwater = 0.0008 mg/L.
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Code Regulation Description Variation There is insufficient data to calculate an EEL for sediment.
E2 Regs 46 – 48 Restrictions on the application of A maximum application rate is set for substances within application areas this substance. The person in charge of the application of this substance, and any person applying the substance, must ensure that the application is carried out in accordance with the following restrictions: the substance must not be applied at rates exceeding 600 mL of formulated product/ha per application (equivalent to 387 g mesotrione /ha); and the substance must not be applied to the same area more than two times in any 330 day period; and an interval of at least 14 full days must be observed before the substance is reapplied to the same area.
E5 Regs 5(2), 6 Requirements for keeping records of use
E6 Reg 7 Requirements for equipment used to handle substances
E7 Reg 9 Approved handler/security This control is only applicable at the requirements for certain ecotoxic ‘use’ phase of Callisto’s lifecycle. substances
Hazardous Substances (Identification) Regulations 2001
Code Regulation Description Variation
I1 Regs 6, 7, 32 Identification requirements, duties of – 35, 36(1) – persons in charge, accessibility, (7) comprehensibility, clarity and durability
I3 Reg 9 Priority identifiers for ecotoxic substances
I9 Reg 18 Secondary identifiers for all hazardous substances
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Code Regulation Description Variation
I11 Reg 20 Secondary identifiers for ecotoxic substances
I16 Reg 25 Secondary identifiers for toxic substances
I17 Reg 26 Use of generic names
I18 Reg 27 Requirements for using concentration ranges
I19 Regs 29 – 31 Additional information requirements, including situations where substances are in multiple packaging
I21 Regs 37 – General documentation requirements 39, 47 – 50
I23 Reg 41 Specific documentation requirements for ecotoxic substances
I28 Reg 46 Specific documentation requirements for toxic substances
I29 Regs 51, 52 Signage requirements
Hazardous Substances (Packaging) Regulations 2001
Code Regulation Description Variation
P1 Regs 5, 6, General packaging requirements 7(1), 8
P3 Reg 9 Criteria that allow substances to be packaged to a standard not meeting Packing Group I, II or III criteria
P13 Reg 19 Packaging requirements for toxic substances
P15 Reg 21 Packaging requirements for ecotoxic substances
PG3 Schedule 3 Packaging requirements equivalent to UN Packing Group III
PS4 Schedule 4 Packaging requirements as specified in Schedule 4
Hazardous Substances (Disposal) Regulations 2001
Code Regulation Description Variation
D4 Reg 8 Disposal requirements for toxic and corrosive substances
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Code Regulation Description Variation
D5 Reg 9 Disposal requirements for ecotoxic substances
D6 Reg 10 Disposal requirements for packages
D7 Regs 11, 12 Information requirements for manufacturers, importers and suppliers, and persons in charge
D8 Regs 13, 14 Documentation requirements for manufacturers, importers and suppliers, and persons in charge
Hazardous Substances (Emergency Management) Regulations 2001
Code Regulation Description Variation
EM1 Regs 6, 7, 9 Level 1 information requirements for – 11 suppliers and persons in charge
EM6 Reg 8(e) Information requirements for toxic substances
EM7 Reg 8(f) Information requirements for ecotoxic substances
EM8 Regs 12 – Level 2 information requirements for 16, 18 – 20 suppliers and persons in charge
EM11 Regs 25 – 34 Level 3 emergency management requirements: duties of person in charge, emergency response plans
EM12 Regs 35 – 41 Level 3 emergency management requirements: secondary containment
EM13 Reg 42 Level 3 emergency management requirements: signage
Hazardous Substances and New Organisms (Personnel Qualifications) Regulations 2001
Code Regulation Description Variation
AH 1 Regs 4 – 6 Approved Handler requirements Refer to control E7 (including test certificate and qualification requirements)
Hazardous Substances (Tank Wagon and Transportable Containers) Regulations 2004
Code Regulation Description Variation
Tank Regs 4 to 43 Controls relating to tank wagons and Wagon as applicable transportable containers
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Additional controls
Code Section of Control the Act
Water 77A This substance must not be applied into or onto water7
App 77A The application of the substance is limited to ground-based application methods method only8 This substance must be applied with nozzles equipped to provide a coarse spray9
Buffer 77A This substance must not be applied within ten metres10 of a downwind11 water Zone body12
This substance must not be applied within 15 metres13 of downwind non-target plants
Sch 8 77A This schedule prescribes the controls for stationary container systems. The requirements of this schedule are detailed in the consolidated version of the Hazardous Substances (Dangerous Goods and Schedule Toxic Substances) Transfer Notice 2004, available from http://www.epa.govt.nz/Publications/Transfer-Notice-35-2004.pdf The following clause replaces Clause 1 of Schedule 8 of the Hazardous Substances (Dangerous Goods and Scheduled Toxic Substances) Transfer Notice 2004: This Schedule applies to every stationary container system that contains, or is intended to contain the substance.
Label 77A The following statements or words to the same effect must be included on the label:
7 Where ‘water‘ means water in all its physical forms, whether flowing or not, and whether over or under ground, but does not include water in any form while in a pipe, tank or cistern or water used in the dilution of the substance prior to application.
8 Ground-based methods of applying pesticides include, but are not limited to, application by ground boom, airblast or knapsack, and do not include aerial application methods
9 A coarse quality spray according to the American Society of Agricultural & Biological Engineers (ASABE) droplet size classification scheme.
10 This distance is the distance between the edge of the application area closest to the water body and the edge of the water in the water body closest to the application area.
11 Downwind refers to a location in a direction to where the wind blows away from the application area’.
12 A water body includes modified water courses such as reservoirs, irrigation canals, water-supply races, canals for the supply of water for electricity generation or farm drainage canals, as well as natural water bodies.
13 This distance is the distance between the edge of the application area closest to the non-target plants and the non-target plants.
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Code Section of Control the Act
A person handling (mix, load or apply) this substance must ensure minimum requirements for PPE are worn:
o Coveralls
o Shoes
o Socks
o Gloves
o Hood/Visor
This substance must not be applied into or onto water
This substance must be applied with nozzles equipped to provide a coarse spray
The application of the substance is limited to ground-based application methods only
The substance must not be applied at rates exceeding 600 mL of formulated product/ha per application (equivalent to 387 g mesotrione /ha).
The substance must not be applied to the same area more than two times in any 330 day period and an interval of at least 14 full days must be observed before the substance is reapplied to the same area.
This substance must not be applied within ten metres of a downwind water body
This substance must not be applied within 15 metres of downwind non-target plants
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Appendix B: Mammalian toxicology
A number of new studies and data reviews for mesotrione have been prepared by the applicant to support registration reviews of this active ingredient in the EU and USA. Those studies considered relevant to the hazard and risk assessment of mesotrione and Callisto are summarised below. Table 3: Phototoxicity studies
Type of study In vitro phototoxicity test
Flag Key study
Test Substance Mesotrione Wet Paste Technical (86.1% mesotrione w/w)
Endpoint Phototoxicity (Photo-Irritation Factor [PIF])
Value Not phototoxic (PIF not able to be determined)
Lehmeier D. (2013) Mesotrione technical: In vitro 3T3 phototoxicity test report final. BSL BIOSERVICE, Scientific Laboratories GmbH, Reference Behringstrasse 6/8, 82152 Planegg, Germany. BSL Study Number: 132889
Klimisch Score 1
Amendments/Deviations None
GLP Yes
Test Guideline/s OECD TG 432 (2004)
Test system BALBc/3T3 cells tested in the presence and absence of UVA light
Dose Levels 0, 0.316, 1.00, 3.16, 10.0, 31.6, 316 and 1000 µg/mL
Cell were exposed to the test item for 1 hour in the dark followed by a 50 Exposure Type minute irradiation period with a solar simulator providing 1.5 - 1.7 mW/cm2 UVA (= 4.5 - 5.1 J/cm2).; non-irradiated group kept in the dark)
Cells treated with the test item did not show cytotoxic effects in the absence or presence of UVA light. Compared to the untreated controls the relative cell viability at the highest test item concentration was 102.4% in the - UVA-experiment and 87.3% in the + UVA-experiment Study Summary 87.3%. Thus, no EC50-values could be determined and a PIF could not be calculated. This indicates no phototoxic potential.
The controls confirmed the validity of the study. The negative controls of the + UVA experiment showed a viability of 93.9% of the untreated
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controls. The mean absolute optical density (OD550) of the Neutral Red
extracted from the untreated controls was ≥ 0.4. The EC50 values of the positive controls of the – UVA (13.96 μg/mL) and the + UVA experiment (0.55 μg/mL) were within the validity ranges and the PIF was > 5, the threshold for a prediction of phototoxicity (25.4).
Additional Comments None
Conclusion No phototoxicity potential
Table 4: Immunotoxicity studies
Type of study Position statement on immunotoxicity
Flag Weight of evidence
Test Substance Mesotrione
Endpoint NA
Value NA
Akkan Z. and Botham J. (2013) Mesotrione - Position statement concerning immunotoxicity potential assessment. Syngenta Ltd, Jealotts Reference Hill International Research Centre, Bracknell, Berkshire RG42 6EY, UK. Report Number: TK0177144
Klimisch Score NA
Amendments/Deviations NA
GLP NA
Test Guideline/s NA
Species NA
Strain NA
No/Sex/Group NA
Dose Levels NA
Exposure Type NA
The purpose of this report was to review the relevant studies in the Study Summary toxicology database for mesotrione for any effects related to immune function. The aim of the assessment was to consider if it is possible to
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make a case to waive EU requirements for supplementary studies on immunotoxicological potential, which are required if considered necessary.
While specific tests in immunotoxicology are designed to assess functional competency of the immune system, it is also important to note that structural immune parameters are routinely evaluated in other standard toxicity studies required for pesticide registration. Thus guideline studies provide acceptable and useful chemical information on the toxic potential, including potential effects on the immune system. More specifically, immune-related endpoints are evaluated by clinical pathology and histopathology in the subchronic (mice, rats and dogs) chronic (dog), and the chronic toxicity/carcinogenicity (mice and rats) studies
Repeated-dose studies in rats, mice and dogs were reviewed for any treatment-related changes in a variety of indicators of potential immunotoxicity including leukocyte counts, lymphocyte counts, globulin concentration, macroscopic findings (lymph nodes, thymus, and spleen), organ weights (spleen and thymus), and microscopic findings (bone marrow, lymph nodes, spleen, and thymus).
There was no evidence of adverse effects of mesotrione on the immune system in rats, mice or dogs. Results of an immunotoxicity study with mesotrione performed in mice (sheep red blood cell assay) confirm that mesotrione has no potential to adversely affect the immune system.
There is no evidence from literature that mesotrione is immunotoxic, and no clinical case reports or poisoning incidences indicating an immunotoxic potential to human are known to the authors. Mesotrione is structurally similar to nitisinone (NTBC), a triketone which is more potent in HPPD inhibition than mesotrione and is used as a drug (Orfadin®) for the treatment of hereditary deficiency in tyrosine catabolism (tyrosinaemia type 1). There are no reports of adverse effects in clinical trials. NTBC is registered globally as an orphan drug and the extensive human experience has not demonstrate an immunotoxic potential in humans even after prolonged exposure.
In addition, mesotrione does not belong to a class of chemicals (e.g., the organotins, heavy metals, or halogenated aromatic hydrocarbons) that would be expected to be immunotoxic.
Additional Comments None
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A thorough review of the toxicology database for mesotrione has shown no evidence of adverse effects on the immune system in rats, mice or Conclusion dogs that would indicate further investigation. Based on these findings within the mesotrione toxicology database, it can be concluded that mesotrione has no immunotoxic potential.
Table 5: Endocrine disrupting properties
Type of study Review of potential for endocrine disruption in mammalian species
Flag Weight of evidence
Test Substance Mesotrione
Endpoint NA
Value NA
Green R. M. (2013) Mesotrione – Review for Potential for Endocrine Disruption in Mammalian Species. Final Report Amendment 1. Syngenta Reference Ltd, Jealotts Hill International Research Centre, Bracknell, Berkshire RG42 6EY, UK. Task number: TK0177145.
Klimisch Score NA
This report amendment was issued in order to include and evaluate Amendments/Deviations relevant in vitro data identified in the open literature after finalisation of the original report.
GLP NA
Test Guideline/s NA
Species NA
Strain NA
No/Sex/Group NA
Dose Levels NA
Exposure Type NA
This report reviews and summarises all of the relevant available data, including open scientific literature, on mesotrione for potential for Study summary endocrine disruption in mammalian species using a weight of evidence approach proposed by the European Chemical Industry Council (CEFIC)
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Endocrine Modulators Steering Group (EMSG), structured according to the OECD Conceptual Framework (CF) for Testing and Assessment of Endocrine Disrupters.
The relevant data from regulatory studies for mesotrione covered a range of study types including subacute, subchronic, chronic, developmental and reproductive toxicity studies in a range of mammalian species including rat, mouse, dog and rabbit. These studies fell within Levels 1, 4 and 5 of the OECD CF, which address any potentially adverse effects on endocrine relevant endpoints. Data from relevant in vitro assays (OECD CF Level 2) was identified in the open literature. No vivo mechanistic studies were available from Level 3 of the OECD CF. Each study was evaluated following the CEFIC weight of evidence approach and was assigned a “study significance” score. This was then incorporated into a general descriptive weight of evidence evaluation.
Effects on endpoints relevant for assessment of potential for endocrine disruption were noted in two studies only:
Multi-generation reproductive toxicity study with rats:
Decreases in number of live born pups and litter size (reductions in litter size can be indicative of abortions/resorptions/intra-uterine deaths)
Two-year oral (dietary) study with rats:
Pale adrenal glands and reduced weights (males only)
Reduced seminal vesicles
Decreased prominence of female mammary gland
Uterine focal swelling
Thyroid follicular cysts with hyperplasia
Thyroid follicular cell adenomas (females only)
Analysis of these studies concluded that most of these effects were a consequence of mesotrione-induced tyrosenaemia or general systemic toxicity.
The effects in the female mammary gland were macroscopic findings with no apparent functional consequence. Therefor in a weight of evidence evaluation, these findings can at most indicate potential to interact with the endocrine system and cannot be considered evidence of endocrine disruption as described in the well-accepted scientific
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definition of an endocrine disrupter. In the absence of any other evidence for an effect on the female rat endocrine system in vivo, including data from a comprehensive suite of developmental and reproductive toxicity studies in which the hormonal status of the female rat is of critical importance in a number of different processes, and the lack of effects in a wide range of oestrogen-related in vitro assays, these isolated findings were not considered to reflect interaction of mesotrione with the endocrine system.
Following evaluation of each of the relevant studies individually and a subsequent weight of evidence evaluation, the study authors concluded that there is no evidence that mesotrione has any potential to interact with the mammalian endocrine system.
Additional Comments None
Based on a weight of evidence analysis there is no evidence to indicate Conclusion that mesotrione has a potential to interact with the mammalian endocrine system.
Conclusion on new mammalian toxicity studies with the active ingredient The new information provided demonstrates that mesotrione does not have phototoxic potential, does not adversely affect the immune system and does not have a potential to interact with the mammalian endocrine system. The new information does not indicate a need to revise the acceptable operator exposure level (AOEL) used for the human health risk assessment.
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Appendix C: Ecotoxicology
The applicant has provided new studies about the effects of three metabolites to the aquatic plant Lemna gibba, and plant bioassays. These studies are summarized below. Table 6: Aquatic plants acute toxicity (Freshwater species) - effects of the metabolite R44276 (AMBA)
Type of study Full test
Flag Key study
R44276 (AMBA, metabolite of Mesotrione) Test Substance Syngenta Code: NOA 422848
Species Lemna gibba
Type of exposure Semi-static, 7 days, renewal after 48 and 72 hours
Endpoint EC50
Value > 90 mg/L
A.Liedtke (2013) R44276 - Toxicity to the Aquatic Higher Plant Lemna gibba in a 7-Day Growth Inhibition Test. Harlan Laboratories Ltd. Reference Zelgliweg 14452 Itingen / Switzerland. Report Number: D55614; Study Number: D55614; Task Number: TK0045839
Klimisch Score 1
Amendments/Deviations None that had an effect on the results
GLP Yes
OECD 221 (2006) Test Guideline/s OPPTS 850.4400 (1996, Public Draft)
No/Group 3 replicates of 5 plants, totalling 15 fronds
0 (control), 0.32, 1.0, 3.2, 10, 32 and 100 mg/L (nominal concentrations)
Dose Levels 0 (control), 0.34, 1.1, 3.3, 10, 33, 90 mg/L (mean measured concentrations)
Yes, from fresh medium and old medium on day 0, 48 and 72h and at the Analytical measurements end of the test, by HPLC
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The impact of the test item R44276 on the growth of the freshwater aquatic plant Lemna gibba (duckweed) was investigated in a 7-day semi- static test.
The measured concentrations of R44276 in the test media of the nominal test concentrations of 0.32 to 100 mg/L were between 93 and 113% of the nominal values at the start of each test interval. At the end of the test periods of 48 and 72 hours, 86 to 104% of the nominal values were found. Thus, the correct dosing of the test item was confirmed. The test item was stable in the test media over the test periods.
The following nominal concentrations of the test item were tested: 0.32, 1.0, 3.2, 10, 32 and 100 mg/L. Additionally, a control was tested in parallel.
The biological results were related to the mean concentrations of the test item calculated as time-weighted means of the test item concentrations measured at the start of the test medium renewals and the concentrations measured in the samples at the end of the renewal periods.
The doubling time (Td) of frond number in the control was calculated to Study Summary be 1.8 days (Td = ln 2 / μ). According to the test guideline, the validity criterion for the study (Td < 2.5 days corresponding to an average growth rate of 0.275 day-l) was fulfilled.
The biological results were as follows (based on mean measured concentrations of the test item R44276):
EC Frond number Dry weight Frond values mortality Growth Yield Growth Yield [mg/L] rate rate
7-day > 90 > 90 > 90 > 90 > 90
EC50
7-day > 90 > 90 > 90 > 90 > 90
EC20
7-day > 90 24 > 90 > 90 > 90
EC10 (3.2 - > 90) 95% C.I.
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7-day > 90 > 90 > 90 > 90 > 90 NOEC
7-day ErC50 and EyC50 > 90 mg/L Conclusion NOEC = 90 mg/L
Table 7: Aquatic plants acute toxicity (Freshwater species) – effects of the metabolite R169649 (MNBA)
Type of study Full test
Flag Key study
Test Substance R169649 (MNBA, metabolite of mesotrione)
Species Lemna gibba
Type of exposure Semi-static, 7 days, renewal after 48 and 72 hours
Endpoint EC50
Value >97 mg/L
A. Liedtke (2013) R169649 - Toxicity to the Aquatic Higher Plant Lemna gibba in a 7-Day Growth Inhibition Test. Harlan Laboratories Ltd. Reference Zelgliweg 14452 Itingen / Switzerland. Report Number: D55592; Study Number: D55592; Task Number: TK0045840.
Klimisch Score 1
Amendments/Deviations None that had an effect on the results
GLP Yes
OECD 221 (2006) Test Guideline/s OPPTS 850.4400 (1996, Public Draft)
No/Group 3 replicates of 5 plants, totalling 15 fronds
0 (control), 0.32, 1.0, 3.2, 10, 32 and 100 mg/L (nominal concentrations)
Dose Levels 0 (control), 0.37, 1.1, 3.3, 10, 32, 97 mg/L (mean measured concentrations)
Yes, from fresh medium and old medium on day 0, 48 and 72h and at the Analytical measurements end of the test, by HPLC
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The impact of the test item R169649 on the growth of the freshwater aquatic plant Lemna gibba (duckweed) was investigated in a 7-day semi- static test.
The following nominal concentrations of the test item were tested: 0.32, 1.0, 3.2, 10, 32 and 100 mg/L. Additionally, a control was tested in parallel.
The measured concentrations of R169649 in the test media of the nominal test concentrations of 0.32 to 100 mg/L were between 96 and 119% of the nominal values at the start of each test interval. At the end of the test periods of 48 and 72 hours, 96 to 117% of the nominal values were found. Thus, the correct dosing of the test item was confirmed. The test item was stable in the test media over the test periods.
The biological results were based on mean measured concentrations calculated as time-weighted means of the test item concentrations measured at the start of the test medium renewals and the concentrations measured in the samples at the end of the renewal Study Summary periods.
The biological results were as follows (based on mean measured concentrations of the test item R169649):
EC Frond number Dry weight Frond values mortality Growth Yield Growth Yield [mg/L] rate rate
7-day > 97 > 97 >> 97 > 97 > 97
EC50
7-day > 97 > 97 > 97 > 97 > 97
EC20
7-day > 97 > 97 > 97 > 97 > 97
EC10
7-day >97 >97 >97 >97 >97 NOEC 32
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7-day ErC50 and EyC50 > 97 mg/L
NOEC = 32 mg/L (yield based on dry weight) Conclusion NOEC = 97 mg/L (growth rate and yield based on frond number and growth rate based on dry weight)
Table 8: Aquatic plants acute toxicity (Freshwater species) – effects of the metabolite SYN546974
Type of study Full test
Flag Key study
Test Substance SYN546974 (Metabolite of mesotrione)
Species Lemna gibba
Type of exposure Semi-static, 7 days, renewal after 48 and 72 hours
Endpoint EC50
Value 7-day ErC50 > 95 mg/L (Frond number)
A.Liedtke (2013) SYN546974 – Toxicity to the Aquatic Higher Plant Reference Lemna gibba in a 7-Day Growth Inhibition Test. Report Number: D77394 Study Number: D77394; Task Number: TK0061226.
Klimisch Score 1
Amendments/Deviations None that had an effect on the results
GLP Yes
OECD 221 (2006) Test Guideline/s OPPTS 850.4400 (1996, Public Draft)
No/Group 3 replicates of 5 plants, totalling 12 fronds
0 (control), 0.10, 0.32, 1.0, 3.2, 10, 32 and 100 mg/L (nominal concentrations) Dose Levels 0 (control), 0.088, 0.29, 0.92, 2.9, 9.4, 28, 97 mg/L (mean measured concentrations – arithmetic mean)
Yes, from fresh medium and old medium on day 0, 48 and 72h and at Analytical measurements the end of the test, by HPLC
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The impact of the test item SYN546974 on the growth of the freshwater aquatic plant Lemna gibba (duckweed) was investigated in a 7-day semi- static test.
The following nominal concentrations of the test item were tested: 0.10, 0.32, 1.0, 3.2, 10, 32 and 100 mg/L. Additionally, a control was tested in parallel.
In the analyzed test medium samples from the start of the test medium renewal periods the measured concentrations of SYN546974 for all test concentrations ranged from 88 to 102% of the nominal values. At the end of the test medium renewal periods of 48 and 72 hours the measured concentrations of SYN546974 for all test concentrations ranged from 80 to 101% of the nominal values.
The biological results were based on mean measured concentrations calculated as time-weighted means of the test item concentrations measured at the start of the test medium renewals and the concentrations measured in the samples at the end of the renewal periods.
Study Summary At the start of the test medium renewal periods, the pH of the test media and the control ranged from 7.5 to 8.2. At the end of the renewal periods, pH values between 8.5 and 9.0 were measured. The increase of the pH
during the renewal periods was caused by the CO2 consumption of the plants due to their growth. The water temperature was maintained at 24 °C during the test period
The biological results of the study are based on the mean measured concentrations of the test item (calculated as the arithmetic mean of all measurements per test concentration):
EC Frond number Dry weight values Growth Yield Growth Yield [mg/L] rate rate
7-day > 95 93 > 95 > 95
EC50 (70-140) (95% C.I.)
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7-day 73 21 > 95 40
EC20 (62-86) (14-29) (25-23) (95%
C.I.)
7-day 32 9.9 68 18
EC10 (23-39) (4.7-15) (54-84) (7.4-28)
(95% C.I.)
7-day 2.9 2.9 9.4 9.4 NOEC
7-day 9.4 9.4 28 28 LOEC
The concentration of 9.4 mg/L was determined to be the 7-day LOEC as the average growth rate and the yield based on frond numbers after the exposure period of 7 days were statistically significantly lower than in the control and symptoms of toxicity were determined at this test concentration. The 7-day NOEC was determined to be 2.9 mg/L since the growth of the plants was not inhibited and only slight chlorosis of the plants was observed after the exposure period of 7 days.
7-day ErC50 > 95 mg/L (Frond number)
7-day EyC50 = 93 mg/L (Frond number)
Conclusion 7-day ErC50 and EyC50 > 95 mg/L (Dry weight)
NOEC = 2.9 mg/L (Frond number)
NOEC = 9.4 mg/L (Dry weight)
Table 9: Terrestrial plants bioassay – effects of ZA1296 (mesotrione) and metabolites AMBA and MNBA
Type of study Plant bioassay
Flag Supporting study
Test Substance ZA1296 (mesotrione) and metabolites AMBA and MNBA
Grass weed (16), Broadleaf weed (14), Sedge weed (2) and Crop Species species (8). For the full list consult the test report.
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Type of exposure Pre-emergence and Post-emergence
Endpoint Herbicidal activity
ZA1296 was effective to control most broadleaf weeds and some
Value grasses at 100 g a.i./ha.
MNBA and AMBA are herbicidal inactive at rates up to 4000 g a.i./ha.
JM Schribbs (1997) Herbicide bioassays of ZA1296 and metabolites Reference AMBA and MNBA (WRC-97-107). Zeneca, Ag Products, Western Research Centre. Study No TMR0704B.
Klimisch Score 2: we have another test more relevant for non-target plant assessment
Amendments/Deviations None that had an effect on the results
GLP Yes
Test Guideline/s Not mentioned
No/Group 7-8 weed species per tray
AMBA: 0 - 4000 g a.i./ha
MNBA: 0 - 4000 g a.i./ha
Dose Levels ZA1296 (Mesotrione): 0 – 4480 g a.i./ha
Solvent: acetone + water
Surfactant: Tween 20
Analytical measurements Not mentioned
ZA1296 (Mesotrione) and metabolites AMBA and MNBA were applied as post-emergences and pre-emergence test in glasshouse screening tests. For the pre-emergence (PRE) the substances were applied to the soil, for post-emergence (POST) tests the substances were applied to the foliage.
Study Summary H2 – Herbicide screen
Treatment trays were prepared by sowing 7-8 weed species (3 annual broadleaves, 3-4 annual and 1 perennial sedge) to a depth of 1.5 cm in 1 L aluminium trays containing a sandy loam soil fortified with a complete fertilizer. Post-emergence trays were sown 11-12 days prior to
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the treatment and pre-emergence sown 1 day prior to treatment. Target growth stages for post-emergence treatment were 3-4 leaf for the grasses, 1-2 leaf for the broadleaves, and 4 leaf for Cyperus esculentus.
ZA1296, AMBA and MNBA were applied at 4 or 4.5 kg a.i./ha. After treatment all plants were placed in a glasshouse at day and night temperature of 21 and 29 °C, respectively, with a 14h daylight regime. The PRE trays were irrigated overhead and the POST trays were irrigated underneath the foliage by using sub-irrigation capillary matting.
Assessment of plant injury were made at 6 and 17-21 days after treatment.
H3 – Herbicide screen
This procedure was similar to the one above, except the spray volume was 400L/ha, a sandy loam with 0.2% OM was used and 24 species were included. Five rates were tested: 32, 63, 125, 250, and 500 g a.i./ha but also lower and higher rates were tested.
Results
ZA1296 controlled all broadleaves except common purselane, yellow nutsedge and some grasses at 125 g a.i./ha or less both PRE and POST. Some broadleaf weeds were controlled over 90% at rates less than 20 g a.i./ha. Corn was not injured in any test at up to 250 g a.i./ha except in one test were corn was injured 15% at 250 g a.i./ha.
ZA1296 was effective to control most broadleaf weeds and some grasses at 100 g a.i./ha.
Conclusion MNBA and AMBA are herbicidal inactive at rates up to 4000 g a.i./ha, less toxic than the active ingredient, therefore no risk assessment was going to be performed for the metabolites.
Table 10: Terrestrial plants – semi field studies
Type of study Semi-field study
Flag Supporting study since this formulation is not Callisto/Tenacity
Test Substance A12739A (formulation containing 100 g mesotrione/L)
Species Lactuca sativa (lettuce) and Lycopersicon esculentum (tomato)
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Type of exposure Post-emergence foliar application
Endpoint ER50 and NOER
ER50 = 1.65 g a.i./ha (biomass); ER50 = 4.25 g a.i./ha (survival); NOER = Value 0.617 g a.i./ha
Porch JR, Martin KH, Kruger HO (2003). ZA 1296 (Mesotrione): A semi- field toxicity test to determine the effects of 100 g ai/L SC formulation (A12739A) on vegetative vigour of each of three different growth stages Reference of Lactuca sativa (lettuce) and Lycopersicon esculentum (tomato). Wildlife International Ltd, Maryland, USA. Project No 528-164. Syngenta Study No 2021792.
Klimisch Score 1
Amendments/Deviations None that have impacted the results
GLP Yes
Test Guideline/s Internal protocol
6 replicates of four plants and 12 control replicates per study group (21- day or 35-day duration) No/Group Growth stages – Lettuce: 1-5 leaves, + 14 days, + 28 days; tomato: 2-3 leaves open, +15 days, + 28 days.
Dose Levels 0 (control), 0.617, 1.85, 5.56, 16.7, 50 and 150 g a.i./ha
Analytical measurements HPLC
Two dicot species Lactuca sativa (lettuce) and Lycopersicon esculentum (tomato) were tested using a single post-emergence application of the test substance. For both species, applications were made to each of the three different growth stages: at approximately 2-4 leaves open and at about 14 and 28 days older than this. Additionally, the early growth stage contained two study groups: one group was harvested 21 days Study Summary after application, and the second was harvested 35 days after application. The purpose of multiple growth stages was to have plants from 3 different distinct ages so that possible trends, if any, in the response could be evaluated. Nominal application rates ranged from 0.617 to 150 g a.i./ha of formulation A-12739A along with a negative control (water purified by reversed osmosis). The soil used was a sandy loam soil with 2% organic matter content and a pH of 7.3. After the first
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true leaves were fully opened, seedlings were moved to an open-air facility reported as shade house with no sides attached allowing free air circulation among the plants during the study period and the roof was a green mesh intended for closure only to provide protection from potentially damaging storms. Otherwise there was no covering over or around the test area.
For both species, biomass was the more sensitive endpoint. The lowest
ER50 estimates on biomass were for the early growth stage of L. sativa, with little change between Day 21 (1.65 g a.i./ha) and Day 35 (2.25 g
a.i./ha). The ER50 estimated for biomass of L. esculentum ranged between 4.46 and 5.66 g a.i./ha. However, evidence from the mortality data indicated a clear reduction in sensitivity with age of plant at
exposure to mesotrione. The ER50 estimates for mortality ranged from 4.25 to 12.8 g a.i./ha for L. sativa and from 7.01 to 23.7 g a.i./ha for L. esculentum.
The lowest ER50 was 1.65 g a.i./ha (biomass). The NOER was 0.617 Conclusion g a.i./ha.
Type of study Semi-field study
Flag Supporting study since this formulation is not Callisto/Tenacity
Test Substance A12739A (formulation containing 100 g mesotrione/L)
Species Brassica rapa (turnip)
Type of exposure Post-emergence foliar application
Endpoint ER50
Value 1.70 g a.i./ha (biomass); 10.7 g a.i./ha (survival)
Porch JR, Martin KH, Kruger HO (2004). ZA 1296 (Mesotrione): A semi- field toxicity test to determine the effects of 100 g ai/L SC formulation Reference (A12739A) on vegetative vigour of each of three different growth stages of Brassica rapa (turnip). Wildlife International Ltd, Maryland, USA. Project No 258-178. Syngenta Study No 2031605.
Klimisch Score 1
Amendments/Deviations None that have impacted the results
GLP Yes
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Test Guideline/s Internal protocol
6 replicates of four plants and 12 control replicates per study group (21- No/Group day or 35-day duration)
Dose Levels 0.617, 1.85, 5.56, 16.7, 50 and 150 g a.i./ha
Analytical measurements HPLC
Brassica rapa (turnip) was tested using a single post-emergence application of the test substance. Applications were made to each of the three different growth stages: at approximately 3-4 leaves open and at about 14 and 28 days older than this. Nominal application rates ranged from 0.617 to 150 g a.i./ha of formulation A-12739A along with a negative control (water purified by reversed osmosis). The soil used was a sandy loam soil with 2% organic matter content and a pH of 7.3. After the first true leaves were fully opened, seedlings were moved to an open-air facility reported as shade house with no sides attached allowing free air circulation among the plants during the study period and the roof Study Summary was a green mesh intended for closure only to provide protection from potentially damaging storms. Otherwise there was no covering over or around the test area.
Biomass was a more sensitive endpoint than survival, and the no observed effects on biomass and survival decreased as the age of
plants at the test substance application increased. The lowest ER50 estimated for biomass ranged from 1.70 g a.i./ha (Day 21) and 10.7 g
a.i./ha (Day 35) The ER50 estimates for mortality in the early life stage ranged from 13.6 and >150 g a.i./ha for the 21-d exposure and from 10.7 to >150 g a.i./ha for 35-d exposure.
Conclusion The lowest ER50 estimated for biomass was 1.70 g a.i./ha.
Type of study Semi-field study
Flag Supporting study since this formulation is not Callisto/Tenacity
Test Substance A12739A (formulation containing 100 g mesotrione/L)
Species Cucumis sativa (cucumber)
Type of exposure Post-emergence foliar application
Endpoint ER50
Value 0.71 g a.i./ha (biomass); 4.90 g a.i./ha (survival)
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Porch JR, Martin KH, Kruger HO (2004). ZA 1296 (Mesotrione): A semi- field toxicity test to determine the effects of 100 g ai/L SC formulation Reference (A12739A) on vegetative vigour of each of three different growth stages of Cucumis sativa (Cucumber). Wildlife International Ltd, Maryland, USA. Project No 258-175. Syngenta Study No 2031605.
Klimisch Score 1
Amendments/Deviations None that have impacted the results
GLP Yes
Test Guideline/s Internal protocol
6 replicates of four plants and 12 control replicates per study group (21- No/Group day or 35-day duration)
Dose Levels 0.617, 1.85, 5.56, 16.7, 50 and 150 g a.i./ha
Analytical measurements HPLC
Cucumis sativa (cucumber) was tested using a single post-emergence application of the test substance. Applications were made to each of the three different growth stages: at approximately 2-4 leaf stage, plants 6 days older and plants 12 days older than this. Nominal application rates ranged from 0.617 to 150 g a.i./ha of formulation A-12739A along with a negative control (water purified by reversed osmosis). The soil used was a sandy loam soil with 2% organic matter content and a pH of 7.3. After the first true leaves were fully opened, seedlings were moved to an open-air facility reported as shade house with no sides attached allowing free air circulation among the plants during the study period and the roof Study Summary was a green mesh intended for closure only to provide protection from potentially damaging storms. Otherwise there was no covering over or around the test area.
Biomass was a more sensitive endpoint than survival, and the no observed effects on biomass and survival decreased as the age of
plants at the test substance application increased. The lowest ER50 estimated for biomass ranged from 0.71 g a.i./ha (Day 21) and 2.19 g
a.i./ha (Day 35) The ER50 estimates for mortality ranged from 4.9 and 14.5 g a.i./ha for the 21-d exposure and from 5.64 and 14.1 g a.i./ha for 35-d exposure.
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The lowest ER50 estimated for biomass were 0.71 g a.i./ha (21 days) Conclusion and 2.19 g a.i./ha (35 days).
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Appendix D: Quantitative human health risk assessment
Due to the new proposed use pattern of Callisto/Tenacity Turf Herbicide a quantitative human health risk assessment was performed. Information on the toxicity of the active ingredient as well as dermal absorption of mesotrione in the formulation was taken from the original Category C application for Callisto (HSR05157).
A turf transferable residue study was provided with the present application and this was used to inform the re-entry and bystander exposure assessments. Table 11: Transferable turf residues
Type of study Transferable turf residues
Flag Key study
Two formulations of mesotrione:
Test Substance Dry granule containing 0.193% mesotrione and a suspension concentrate containing 40.2% mesotrione.
Endpoint Transferable turf residue
Value 0.319 % of the application rates
Lange B. D. (2007) Mesotrione - Determination of transferable turf residues on turf treated with granular and liquid formulations. Final report. Reference Access Research and Consulting, Inc, 4720 W. Jennifer Avenue, Suite 106, Fresno, CA 93722 USA. Report Number: AR26073.
Klimisch Score 1
Amendments/Deviations None that would impact either the results or the conclusions.
Yes (with certain exemptions which are not considered to adversely GLP impact the integrity of the study)
Test Guideline/s US EPA 875.2100
Species NA
Strain NA
No/Sex/Group NA
Dose Levels NA
Exposure Type NA
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Two formulations of mesotrione, a dry granular containing 0.193% active ingredient (a.i.) and a sprayable suspension concentrate containing 40.2% a.i. were tested. The target test substance application rate for both formulations was 0.25 lb a.i./A (280 g/ha). The liquid formulation test substance was applied using a tractor mounted ground boom sprayer, while the granular formulation was applied using a drop spreader.
The study was conducted at three geographical locations representative of the spectrum of climatic conditions and turf types expected in the intended-use areas: New York, California and Georgia. Each field site consisted of two treated plots, one for each formulation. All untreated control samples (pre-application samples) were collected prior to application of the test substance. Each treated plot was divided into subplots from which three replicate samples were collected randomly at each sampling interval. Targeted sampling intervals were: preapplication, immediately post application, 4, 8, and 24 hours after treatment, and 2, 3, 5, 7, 10, 14, and 21 days after treatment.
During the study, temperatures varied from 3-21, 3-30 and 5-33 0C at the New York, California and Georgia site respectively. All sites either had Study Summary natural rainfall or had some irrigation to simulate rainfall. While the humidity for the study in Georgia was not reported the humidity at the other two sites varied from 16- 100 %.
Samples were collected using the Modified California roller technique which involves rolling a specific roller over a white 100% cotton percale 200-thread cloth (27 in x 39 in). After collection, samples were wrapped in foil, put into plastic recloseable bags and stored in freezers until shipment to the analytical laboratory. The analytical method was validated prior to analysing treated study samples with a limit of quantitation (LOQ) of 0.00018 μg/cm2 and freezer storage stability was demonstrated for the duration of storage of treated samples. Field fortifications of cloth media were prepared twice at each of the field sites. Overall mesotrione recoveries averaged 94.6% ± 5.56 %, 92.9% ± 8.25 % and 83.3% ± 8.62%, at the New York, California, and Georgia sites, respectively.
Mesotrione transferable residues were detected at low levels at all sites, decreasing to less than the limit of quantitation by 7 days after treatment at the New York site, by 14 days after treatment at the California site, and by 10 days after treatment at the Georgia site. The highest average initial residues occurred in the first day of sampling. The following table shows
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the post-application sampling interval residues, as percent of application rate, for each formulation at the three field sites.
Average Percent (%) of Application Rate Transferred
at the Post Application Sampling Interval
New California Georgia Average York
Dry Granular 0.0771 0.163 0.170 0.137
Formulation
Suspension 0.0956 0.319 0.165 0.193
Concentrate
Formulation
Dis lodgeable half-lives (days)
New California Georgia Average York
Dry Granular 1.04 2.88 2.34 2.08
Formulation
Suspension 1.16 1.98 1.52 1.55
Concentrate
Formulation
Based on the results of the study and uncertainties associated with the use of data collected in the USA for New Zealand, EPA staff consider that the appropriate TTR to use for this substance (a liquid formulation) is 0.319 % and the appropriate foliar half-life should be 2 days.
Given that this study was conducted on turf (which is the same as the proposed use in New Zealand), staff consider that it is appropriate to use the TTR value as the dislodgeable foliar residue (DFR) value in the risk assessment.
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Conclusion TTR = 0.319 % and the foliar DT50 = 2 days.
Worker risk assessment
Critical endpoint definition Has an AOEL already been set by an internationally reputable regulatory authority accepted by EPA?
Yes No Table 12: existing AOEL for mesotrione Available Key NOAEL AOEL Uncertainty Staff’s international systemic mg/kg mg/kg Remarks factors modifications AOELs effect bw/Day bw/Day
Decreased Adjusted organ for 70% weights in oral adults and absorption; EPA (NZ) pups 2 100 0.015 None based on (mouse EU AOEL multigener (see ational HSR05157 study) )
Decreased organ weights in Adjusted adults and for 70% EU pups 2 100 0.015 None oral (mouse absorption multigener ational study)
Other inputs for human worker (operator) and re-entry exposure modelling14 Table 13: The derivation of dermal absorption value in humans Maximum Dermal absorption (%) application rate Physical Concentration AOEL (for each active, for Active form of each active mg/kg each method of (g/L) Concentrate Spray bw/day application) g a.i./ha
Mesotri Liquid 480 290 1 3 0.015 one
14 The Staff has undertaken an assessment of risks to operator health using the EPA’s exposure assessment model which is based on the models used in the EU. The full methodology can be provided on request.
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The science memo and Evaluation & Review reports for the original application for Callisto state that the applicant had calculated from human volunteer data that the dermal absorption from Callisto formulation during mixing/loading is 1% and is 3% from the spray application. These values were used in the previous risk assessment and are proposed to also be used for the current assessment.
Output of the human worker exposure assessment Table 14: Output of human worker (operator) mixing, loading and application exposure modelling Estimated operator Risk Exposure Scenario exposure (mg/kg bw/day) Quotient
Boom
No PPE15 during mixing, loading and application 0.0180 1.20
Gloves only during mixing and loading 0.0135 0.90
Gloves only during application 0.0159 1.06
Full PPE during mixing, loading and application 0.0016 0.11 (excluding respirator)
Full PPE during mixing, loading and application 0.0013 0.09 (including respirator)
Backpack - High Level Target
No PPE during mixing, loading and application 0.0150 1.00
Gloves only during mixing and loading 0.0073 0.49
Gloves only during application 0.0138 0.92
Full PPE during mixing, loading and application 0.0026 0.17 (excluding respirator)
Full PPE during mixing, loading and application 0.001523 0.10 (including respirator)
The exposure assessment indicates that risks are controllable by the use of PPE. Full PPE is recommended (gloves, hood/visor, coveralls, and heavy boots without a respirator) during mixing, loading, and application in order to reduce the risks to an acceptable level
Output of the re-entry exposure assessment For this assessment the EPA have used the information provided by the applicant about the TTR values to determine the Dislodgable Foliar Residue (DFR). Based on the fact that the highest TTR was calculated to be 0.319 % of the application rate, staff calculated that the DFR would be 0.0319
15 Full” PPE includes: gloves, hood/visor, coveralls, and heavy boots during application. The model only provides for use of gloves at mixing loading.
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µg/cm2/kg a.i. applied per hectare (based on the fact that 0.319 % of 1 kg/ha is equal to 3.19 g/ha which is equivalent to 0.0319 µg/cm2/kg a.i./ha). This is significantly less than the default value of 3 µg/cm2/kg a.i./ha, however staff believe that it better reflects the fact that very low levels of this substance are dislodgable from turf. In addition staff assumed a foliar half-life (DT50) value of 2 days based on the results of the TTR study. Table 15: Re-entry exposure modelling16 Risk Quotient Internal (absorbed) dose available AOEL immediately after Re-entry Activity for systemic distribution (mg/kg application (mg/kg bw/8 hours) bw/day) without gloves
Turf irrigation/mowing 3.20 x 10-5 0.015 2.13 x 10-3
Turf hand 6.39 x 10-4 0.015 4.26 x 10-2 weeding/transplanting
Risks to re-entry workers are less than the level of concern, however, it is recommended that workers should wait until the spray has dried before re-entering as this is considered good practice. Bystander risk assessment17
Critical endpoints definition The AOEL derived for operator and re-entry worker assessment above is also used for the bystander assessment calculations.
Output of human bystander exposure modelling18 For this assessment staff have used the results of the study provided by the applicant to determine what the TTR and foliar half-life of this substance should be. Staff used TTR values of 0.319 % and a foliar half live of 2 days. This is significantly less than the default values of 5 % and 10 days, however, staff believe that the information provided by the applicant is of good quality and more relevant and appropriate to use than default values.
16 The Staff assessed the re-entry worker exposures using the EPA’s exposure assessment model which is based on the models used in the EU together with equations used by the US EPA. The full methodology can be provided on request.
17 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 sub-population 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.
18 Exposure is estimated using the EPA’s exposure assessment model which is based on the models used in the EU together with equations used by the US EPA. The full methodology can be provided on request. Spray drift is estimated using models specific to the type of application equipment. For pesticides applied by ground boom or air blast sprayer, the AgDrift model is used.
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Table 16: Exposure scenario Estimated exposure of 15 kg toddler exposed Exposure Scenario through contact to surfaces 8 m from an Risk Quotient application area (µg/kg bw/day) Boom
High boom, fine droplets 0.12 0.0079
High boom, coarse droplets 0.02 0.0013
Low boom, fine droplets 0.04 0.0027
Low boom, coarse droplets 0.01 0.0006
The risks to bystanders 8 m away from the site of application are acceptable. However, as the substance is intended to be applied to turf which can include sports grounds and other amenity turf/grassland areas, Staff have also assessed the risks from re-entry to undertake recreational activities, i.e. ‘recreational exposure’. The scenario assessed is based on the exposure of a toddler present for two hours on a surface that has been directly treated with the substance. The results are presented below. Table 17: Estimated exposure of 15 kg toddler Estimated exposure of 15 kg toddler directly exposed to the Risk Quotient application area (µg/kg bw/day)
1.22 0.08
Outcomes of the bystander exposure assessment The risks to bystanders are acceptable, both for bystanders in an area adjacent to where the substance has been applied and for members of the public entering treated areas to undertake recreational activities. Summary and conclusions of the human health risk assessment
This risk assessment indicates that provided the substance is used in accordance with the label instructions and the proposed controls the exposures of operators, re-entry workers and bystanders (both bystanders in an area adjacent to where the substance has been applied and members of the public entering treated areas to undertake recreational activities) are expected to be lower than the AOEL and therefore below the level of concern.
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Appendix E: Quantitative ecological risk assessment
Due to the new proposed use pattern of Tenacity Turf Herbicide, a quantitative environmental risk assessment was performed. Data for the environmental risk assessment was sourced from the science memo of previous applications. The staff used the new data provided by the applicant when deemed appropriate for the risk assessment. Environmental fate data Table 18: Summary of environmental fate data on mesotrione and its metabolites – Values in bold are used for the risk assessment
Test Mesotrione AMBA MNBA
Stable at pH =5, pH=7, pH=9. Hydrolysis (25 and 50 Less than 10% degradation after 30 days at 25 ºC ºC) and after 5 days at 50 ºC .
Aqueous photolysis Half life = 83.7 days (irradiation corresponding to
º (pH = 7, 25 ºC) 40 days of natural sunlight at 37 N).
160 mg/L in unbuffered water at 20ºC
Water solubility 15 000 mg/L at pH 6.9 at 20ºC
22 000 mg/L at pH 9 at 20ºC
Partition coefficient Log Kow < -1 (at 20 ºC)
Aerobic degradation Max 14% (water/sediment) DT50 = 3 days (sandy loam sediment) after 14 (same value for water DT50 = 6 days (sand sediment) days. and whole system)
Considered not to be bioaccumulative based on the Bioaccumulation Log Kow < 3.
DT50 Soil type
(days) Aerobic degradation in soil (laboratory at 20-25 14 Silty loam ºC) 4.1 Silty loam
12 Silty loam
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Test Mesotrione AMBA MNBA
5.9 Loam
4.5 Clay loam
22 Clay loam
10.6 Silty clay loam
16.6 Silt loam
25.9 Loamy sand
8 Loam
24.1 Clay loam
8.5 Loam (sandy)
12.9 Silt loam
19.1 Clay loam
14.4 Silty clay loam
15.8 Silty clay loam
31.5 Silty clay loam
8.2 Silty clay loam
6.5 Loamy sand (0-10 cm)
13 Sand (0-10 cm)
80% upper limit of the mean = 16.1 days
DT50 Soil type
(days) (0-10 cm)
7 Clay loam
Aerobic degradation in 7.6 Sandy loam soil (field) 7 Clay loam
5.4 Sandy clay loam
7.8 Loam
1.9 Sandy clay loam
Anaerobic aquatic soil 42% (0.031 3.6 d (at 20 ºC; phenyl label) metabolism (laboratory) ppm) in the
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Test Mesotrione AMBA MNBA
floodwater after 14 days and 66% (0.129 ppm) in the soil after 30 days
12.3% Soil photolysis Half-life = 28.9 d (40 ºN); 31.8 days at 50 ºN (irradiated (laboratory at 20 ºC) (calculated). conditions)
Koc Kd %OC pH Soil (adsorption) type (L/kg)
47 0.74 1.58 6.2 Silt loam
25 0.13 0.53 8.2 Sandy loam
171 4.49 2.63 5.1 Silty clay loam
70 1.25 1.79 6.5 Clay
14 0.14 1.03 7.8 Loam
Adsorption/desorption 60 0.34 0.57 6.5 Sandy loam
15 0.13 0.86 7.7 Loam
52 0.67 1.26 6.1 Silt loam
33 1.1 3.28 7.7 Clay loam
390 2.3 4.6 Loamy sand
240 5.0 5.0 Silt loam
250 3.4 5.0 Loam
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Test Mesotrione AMBA MNBA
210 4.4 5.1 Silty clay loam
110 1.1 5.3 Loam
73 1.3 5.3 Silty clay loam
98 1.6 5.6 Silt loam
120 1.0 5.5 Silt loam
90 0.68 6.0 Silt loam
70 0.74 6.0 Silt loam
60 0.63 6.4 Silty clay loam
37 0.82 6.6 Clay loam
29 0.61 7.5 Silty clay loam
Photodegradation in air -
Ecotoxicologically - relevant compounds
- No data provided
Conclusion about the environmental fate and behaviour
Mesotrione is hydrolytic stable at a pH between 5 and 9. The DT50 in a water/sediment system was 6 days. Mesotrione is moderate soluble in water and is considered not to be bioaccumulative, based on the Log Kow value. Mesotrione is considered not to be persistent in soil. The calculated 80% upper
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limit of the mean DT50 was 16 days. Mesotrione persistence in soil seems to be affected by soil pH and organic matter content. Field dissipation studies indicate that mesotrione is not persistent (DT50 below 8 days) and that no metabolites are present in the upper layer (0-10 cm). While the water solubility and low binding constants indicate potential for high soil mobility, the field dissipation results suggest that there is little migration of mesotrione or its metabolites below 10 cm in the soil. Mesotrione is mobile in soil according to the FAO scale. In general, Kd correlates inversely with the pH and directly with the soil organic carbon content. Two major metabolites result from the degradation of mesotrione: AMBA and MNBA. Summary of ecotoxicological data on mesotrione and its metabolites Table 19: Summary of ecotoxicological data on mesotrione and its metabolites – Values in bold are used for the risk assessment
Test Mesotrione Callisto AMBA MNBA SYN546974
Rainbow Trout: Rainbow
LC50 > 120 mg/L trout: Bluegill Sunfish: 150 mg/L Rainbow LC50 > 120 mg/L Rainbow Trout: trout: Acute / fish Sheepshead LC50 > 180 mg/L LC50 > minnow: LC50 = 120 mg/L 410 mg/L
Common carp:
LC50 >97.1 mg/L
Acute / aquatic EC50 = EC50 = invertebrates EC50 = 900 mg/L EC50 > 180 mg/L 160 mg/L 130 mg/L (Daphnia magna)
ErC50 = 14 ErC50 = ErC50 = 13 mg/L ErC50 = 26 mg/L mg/L 42 mg/L Algae EbC50 = 4.5 mg/L EbC50 = 8.8 mg/L EbC50 = EbC50 = (Green algae) NOEC = 0.75 9.4 mg/L 38 mg/L
mg/L
ErC50 = 0.012 mg/L
ErC50 = 0.022 (corresponding to Aquatic plant mg/L 0.0049 mg a.i./L) ErC50 > 90 ErC50 > ErC50 > 95 (duckweed, Lemna EbC50 = 0.077 EbC50 = 0.053mg/L mg/L 97 mg/L mg/L sp.) mg/L NOEC = 0.0025 mg/L
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Test Mesotrione Callisto AMBA MNBA SYN546974
Chronic / fish NOEC = 12.5 mg/L 36 post-hatch early - life stage (ELS) LOEC = 25 mg/L
Reproduction
Daphnia NOEC = 180 - (21 days life cycle, mg/L semi-static)
EC50 and NOEC > 2000 mg a.i/kg soil
LC50> 437.7 mg a.i./kg at 14 days based on a formulation LC50 ≥ 2000 mg/kg Acute / earthworm containing 100 g - - - dry soil a.i./L.
NOEC = 117.5 mg a.i./kg at 14 days based on a formulation containing 100 g a.i./L.
Chronic / - - - - - earthworm
Seedling emergence and survival
Terrestrial plants Monocot – Allium cepa, onion: (Laboratory studies) NOER = 7.8 g a.i./ha
ER25 = 35.8 g a.i./ha
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Test Mesotrione Callisto AMBA MNBA SYN546974
ER50 = 67.9 g a.i./ha (21-d survival)
Dicot – Lactuca sativa, lettuce):
NOER = < 2.6 g a.i./ha
ER25 = 1.65 g a.i./ha
ER50 = 4.19 g a.i./ha (21-d survival)
Vegetative vigour
Monocot – Glycine max soybean:
NOER = 2.59 g a.i./ha (survival)
ER25 = 6.67 g a.i./ha
ER50 = 15.59 g a.i./ha
Dicot – Lactuca sativa, lettuce:
NOER = 0.096 g a.i./ha (biomass)
ER25 = 0.602 g a.i./ha (biomass)
ER50 = 0.93 g a.i./ha (biomass)
Terrestrial plants – Lettuce
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Test Mesotrione Callisto AMBA MNBA SYN546974
semi-field studies ER50 = 1.65 g a.i./ha (biomass)
ER50 = 4.25 g a.i./ha (biomass)
Formulation containing 100 g a.i./L, not “Callisto/Tenacity”
No adverse Soil micro- effect at 28 days organisms at 400 g a.i../ha,
(Nitrogen based on a study mineralization and using a Carbon formulation mineralization) containing 100 g a.i./ha.
Japanese quail:
Acute / bird LD50 > 2000 - mg/kg bw
Mallard duck:
LC50 > 5200 Short-term / bird mg/kg feed -
Bobwhite: LC50 > 5200 mg/kg feed
Bobwhite quail: NOEC ≥ 3000 Reproduction bird - ppm diet
Oral LD50 > 105 µg Oral LD50 > 11 a.i./bee µg a.i./bee
Acute / bees Contact LD50 > Contact LD50 > 125 µg a.i./bee 100 µg a.i./bee
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Test Mesotrione Callisto AMBA MNBA SYN546974
Contact LD50 > 9.1 µg/bee (Formulation containing 100 g a.i./L)
LR50 > 150 g ai/ha, no significant effect on fecundity of Typhlodromus pyri; 7 days, glass plate Non target 48hr-LR50 = 159 g arthropods ai/ha, no significant effect on fecundity of Aphidius rhopalosiphi
- No data provided Risk assessment Methodology
Methods used to assess environmental exposure and risk differ between environmental compartments Table 20: Reference documents for environmental exposure and risk assessments Environmental Risk assessment exposure
Overview of the Ecological Risk Assessment Process in (GEN)eric (E)stimated the Office of Pesticide (E)nvironmental Programs, U.S. Aquatic organisms (C)oncentration Model Environmental Protection Version 2.0 – 01 August Agency. Endangered 2002 and threatened Species Effects Determinations – 23 January 2004
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Environmental Risk assessment exposure
AgDrift and EPA Software19
Guidance on information Guidance on information requirements and requirements and chemical safety chemical safety assessment, Chapter Sediment organisms assessment, Chapter R.10: Characterisation of R.16: Environmental dose [concentration]- Exposure Estimation, response for Version: 2 - May 2010 environment – May 2008
Soil persistence models and EU registration. The SANCO/10329/2002 rev final report of the work of 2 final. Guidance Soil organisms, the Soil Modelling Work Document on terrestrial invertebrates (macro- group of FOCUS (FOrum ecotoxicology under invertebrates) for the Co-ordination of Council Directive pesticide fate models and 91/414/EEC- 17 October their USe) – 29 February 2002 1997
Guidance for assessing pesticide risks to Bees bees. US EPA, Health Canada Pest Management Regulatory Agency, California
19 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 spray drift.
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 off-site 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 unlike GENEEC2, AgDRIFT® model only considers transport by spray drift, input through runoff, volatilisation, etc. will pose additional risks.
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Environmental Risk assessment exposure
Department of Pesticide Regulation, 19 June 2014
Guidance document on regulatory testing Terrestrial organisms, and risk assessment procedures for plant invertebrates (non-target protection products with non-target arthropods) arthropods. From ESCORT 2 Workshop – 21/23 March 2000
Guidance of EFSA. Risk assessment to birds and mammals – 17 December 2009.
EFSA calculator tool - 200920 Terrestrial vertebrates (birds) 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 Guidance of EFSA. Risk assessment in support of assessment to birds and Commission Directive mammals – 17 93/67/EEC on Risk December 2009 Assessment for new notified substances, EFSA calculator tool - Commission Regulation 2009 Secondary poisoning and (EC) No 1488/94 on Risk biomagnification SANCO/4145/2000 final. Assessment for existing Guidance Document on substances, Directive risk assessment for birds 98/8/EC of the European and mammals under Parliament and of the Council Directive Council concerning the 91/414/EEC- 25 placing of biocidal September 2002 products on the market – Part II - 2003
Consideration of threatened native species
20 www.efsa.europa.eu/en/efsajournal/pub/1438.htm
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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 endangered species for which the survival of the population could depend on the survival of each and every individuals.
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, naturally uncommon). 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. 퐸퐸퐶 퐴푐푢푡푒 푅푄 = 푠ℎ표푟푡−푡푒푟푚 퐿(퐸)퐶50
퐸퐸퐶 퐶ℎ푟표푛𝑖푐 푅푄 = 푙표푛𝑔−푡푒푟푚 푁푂퐸퐶
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 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.
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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 21: Level of concern Endpoint LOC Presumption
Aquatic (fish, invertebrates, algae, aquatic plants)
Acute RQ ≥ 0.5 High acute risk
Risk can be mitigated through restricted Acute RQ 0.1 - 0.5 use
Acute RQ < 0.1 Below the level of concern
Chronic RQ ≥ 1 High chronic risk
Aquatic threatened species
Acute RQ ≥ 0.05 High acute risk
Chronic RQ ≥ 0.1 High chronic risk
Plants (terrestrial)
≥ 1 calculated on the basis of Acute RQ High acute risk EC25
≥ 5 calculated on the basis of Or Acute TER High acute risk EC50
Threatened plants species (terrestrial)
≥ 1 calculated on the basis of Acute RQ High acute risk the NOEC or EC05
GENEEC2 modelling
Calculation of expected environmental concentrations Table 22: The parameters used in GENEEC2 modelling Turf Mesotrione
Application rate (g ai/ha) 290
Application frequency 2
Application interval (days) 14
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Turf Mesotrione
Koc* 14
Aerobic soil DT50 (days)** 16.1
Pesticide wetted in? No
Methods of application Low Boom, fine droplets, no incorporation
‘No spray’ zone None
Water solubility (ppm) 15 000
Hydrolysis (DT50 in days) stable
Aerobic aquatic DT50 whole system (days) 6
Aqueous photolysis DT50 (days) 83.7
*Lowest value of a non sand soil
**Upper 80% limit of the mean value
Output from the GENEEC2 model for mesotrione
RUN No. 1 FOR Mesotrione ON Turf * INPUT VALUES *
------
RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE NO-SPRAY INCORP
ONE(MULT) INTERVAL Koc (PPM ) (%DRIFT) (FT) (IN)
------
0.258( 0.399) 2 14 14.015000.0 GRLOFI( 2.9) 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)
------
16.10 2 0.00 83.70-10378.80 6.00 6.00
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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
------
20.39 18.60 11.63 5.40 3.67
The maximum Estimated Environmental Concentration (EEC) for mesotrione when used in Tenacity Turf Herbicide as estimated by GENEEC2 is 20.32 μg/L.
Calculation of acute risk quotients using GENEEC2 expected environmental concentrations Table 23 gives calculated acute risk quotients for each trophic level considering EEC estimated by GENEEC2 and lowest relevant toxicity figures. Table 23: Acute risk quotients derived from the GENEEC2 model and toxicity data Peak EEC from LC50 or EC50 Trigger value / Species GENEEC2 Acute RQ (mg/L) Presumption (mg/L)
Turf – 290 g a.i./ha, 2 applications at 14 days interval
Fish >97.1 0.00021 < 0.1 / No concern
Daphnids 900 0.000226 < 0.05 / No concern for threatened species Algae 13 0.0016
Aquatic plant, Lemna ≥ 0.5 / High risk gibba 0.0204 0.022 0.93 ≥ 0.05 / High risk for (Mesotrione) threatened species
Aquatic plant, Lemna ≥ 0.5 / High risk gibba 0.0049 4.2 ≥ 0.05 / High risk for (“Callisto”) threatened species
Calculation of chronic risk quotients using GEENEC2 expected environmental concentrations
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Because the metabolites (AMBA and MNBA) were more toxic to Daphnids than the parent compound mesotrione, the staff also calculate the risk quotients for these two metabolites. The RQ were 0.0013 and 0.0015 for AMBA and MNBA, respectively. Therefore, the risks of the two metabolites were below the level of concern for aquatic invertebrates.
Table 24 gives calculated chronic risk quotients for each trophic level considering EEC estimated by GENEEC2 and lowest relevant toxicity figures. Table 24 Chronic risk quotients derived from the GENEEC2 model and toxicity data Relevant EEC NOEC Chronic Trigger value / Species from GENEEC2 (mg/L) RQ Presumption (mg /L)*
Turf – 290 g a.i./ha, 2 applications at 14 days interval
Fish (32 d, ELS) 12.5 0.0015 < 1 / No concern
0.0186 Invertebrates Daphnia magna < 0.1 / No concern for 180 0.0001 (21 d) threatened species
* EEC selected must be as close as possible from the exposure duration of the study selected for risk assessment purpose.
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.
Conclusion for the aquatic risk assessment using GENEEC2 data Risks were considered below the level of concern for fish, algae and aquatic invertebrates (acute and chronic).
High risks were identified for aquatic plants (Lemna sp.). Freshwater vascular plants are listed as nationally critical, nationally endangered, nationally vulnerable or declining either in freshwater bodies or in wetlands (https://www.niwa.co.nz/freshwater/update/freshwater-update-56-january- 2013/conserving-threatened-aquatic-and-wetland-plants). The staff consider that there is a need to apply mitigation measures to protect aquatic plants.
AgDRIFT modelling 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.
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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.
The staff consider that for the protection of threatened species an additional safety factor for the calculation of the buffer zone should be used. Thus, the lowest acute figure was divided by an additional safety factor to calculate the buffer zone needed to protect aquatic threatened species. Based on the application rate recommended for Tenacity Turf Herbicide for the use in turf, the maximum number of applications per year (2 with a 14 days interval), a low volume ground based spray using coarse nozzles, the environmental fate characteristics and the lowest acute figure for the most sensitive taxa (ErC50 = 0.0049 mg/L) for mesotrione, the model concludes that there is a need to define a buffer-zone of 12 meters to protect the aquatic threatened species if the product is applied downwind to an adjacent water body.
The EPA staff consider that additional controls should be set to this substance:
1) Tenacity Turf Herbicide should not be applied into or onto water;
2) Tenacity Turf Herbicide can only be sprayed using a low volume ground based with a nozzle set to provide a coarse spray;
3) The maximum application rate of Tenacity Turf Herbicide is 290 g ai/ha, 2 applications per year with a minimum 14 days interval between applications.
4) A buffer zone of 10 meters is set when Tenacity Turf Herbicide is applied downwind to an adjacent water body.
Groundwater risk assessment
Calculation of expected environmental concentrations in groundwater with Sci-Grow Table 25: Input parameters for Sci-Grow analysis and resulting PEC values Turf Mesotrione
Application rate (kg ai/ha) 0.290
Application rate (lb/acre) 0.258
Number of applications 2
Koc* 14
Aerobic soil DT50 (days)** 16
PECgw (µg/L) 0.159
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* Lowest Koc of a non sand soil
** Same input value as for GENEEC2
Conclusion for the groundwater risk assessment using SciGrow Estimated concentrations of mesotrione were slightly above the unofficial threshold of 0.1 µg/L (0.159 µg/L). Degradation of mesatrione in field conditions is rapid and although mesatrione is mobile in the soil there is no evidence of leaching to the lower layers. Therefore, the staff consider that no significant contamination of groundwater is expected in the use conditions of Tenacity Turf Herbicide.
Sediment risk assessment No specific calculation is performed for sediment dwelling organisms because there was no data was available. 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 to determine whether a substance poses an environmental risk are provided below:
Table 26: Levels of concern Level of Concern (LOC) Presumption
Earthworm/ Birds
Acute TER < 10 High risk
Chronic TER < 5 High risk
Threatened Bird species
Acute TER < 20 High risk
Chronic TER < 10 High risk
Threatened soil organisms species
Acute TER < 100 High risk
Chronic TER < 50 High risk
Bees
Acute RQ oral/contact > 0.4 High risk
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Chronic RQ > 1 High risk
Terrestrial invertebrates
HQ in-field/off-field ≥2 High risk
For more details about the different factors used for calculating TER and RQ refer to the relevant reference documents listed in Error! Reference source not found..
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’
푎푝푝푙𝑖푐푎푡𝑖표푛 푟푎푡푒 (kg a.i./ha) 푃퐸퐶 표푛푒 푎푝푝푙𝑖푐푎푡𝑖표푛 (mg/kg soil) = × 100 75 푘푔 푠표𝑖푙
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/m3, 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:
(1 − 푒−푛푘𝑖) 푃퐸퐶 푚푢푙푡𝑖푝푙푒 푎푝푝푙𝑖푐푎푡𝑖표푛푠 = 푃퐸퐶 표푛푒 푎푝푝푙𝑖푐푎푡𝑖표푛 × (1 − 푒−푘𝑖) where: n = number of applications
-1 k = ln2/DT50 (day ) i = interval between two consecutive applications (days)
o DT50 = half life in soil (days) Use only DT50 values of lab test done at 10-20 C 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 27 and Table 28.
Calculation of TERs
퐿퐷 푇퐸푅푎푐푢푡푒 = 50 퐸푠푡𝑖푚푎푡푒푑 퐸푛푣𝑖푟표푛푚푒푛푡푎푙 퐶표푛푐푒푛푡푟푎푡𝑖표푛
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푁푂퐸퐶 푇퐸푅푙표푛푔 − 푡푒푟푚 = 퐸푠푡𝑖푚푎푡푒푑 퐸푛푣𝑖푟표푛푚푒푛푡푎푙 퐶표푛푐푒푛푡푟푎푡𝑖표푛
Table 27: Acute in-field TER value for earthworms
PEC (mg/kg LC50 Trigger value / Scenarios TER acute soil) (mg/kg soil) Presumption
>10 / No concern Turf, 2 applications of 290 g 0.060 > 2000 > 33333 >100 / No concern for ai/ha at 14 days interval threatened species
Table 28: Acute off-field TER value for earthworms
PEC (mg/kg LC50 Trigger value / Scenarios TER acute soil) (mg/kg soil) Presumption
>10 / No concern Turf, 2 applications of 290 g 0.017 > 2000 117747 >100 / No concern for ai/ha at 14 days interval threatened species
Conclusion for earthworm acute risk assessment Tenacity Turf Herbicide shows acute risk to earthworms below the level of concern in field and off- field conditions. There were no data for chronic effects of Tenacity Turf Herbicide or mesotrione to earthworms. However, no effects were observed in the acute tests and the active ingredient is not persistent in soil. Acute risks to earthworms in field and off-field conditions were below the level of concern.
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 29: Basic drift values for 2 applications Ground deposition in % of the application rate (82nd percentile)
Field Vegetables Ornamentals Distance Fruit crops Grapevine Hops crops Small fruit
Height Height [m] Early late Early late < 50 cm > 50 cm
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1 2.38 2.38
3 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
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 a.i./ha). Effects data are represented by ER50 values from the studies, also expressed as g a.i./ha.
The approach for threatened species is based on a RQ approach and the lowest NOER obtained from the study with Callisto/Tenacity formulation. Table 30: RQ value for non-target plant Exposure =
drift x ER25/ ER50 Trigger value / Scenario – Turf Drift (%) RQ application (g ai/ha) Presumption rate (g ai/ha)
2.38 at 1 m 6.902 1.65 4.2 >1 / High risks Seedling Emergence 0.47 at 5 m 1.363 1.65 0.8 < 1 / No concern
2.38 at 1 m 6.902 0.602 11.5 >1 / High risks Vegetative vigour - Survival 0.47 at 5 m 1.363 0.602 2.3 >1 / High risks
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0.24 at 10 m 0.696 0.602 1.15 >1 / High risks
0.16 at 15 m 0.464 0.602 0.77 < 1 / No concern
Conclusion for non-target plant risk assessment Tenacity Turf Herbicide, when applied to turf presents a high risk to non-target plants. A downwind buffer zone of 15 m is necessary to reduce the exposure of non-target plants to acceptable levels of spray drift.
EPA used AgDrift to calculate the buffer zone needed to protect non-target plants using the lowest
NOER of 0.096 g ai/ha. This resulted in a buffer zone of 275 m to protect non-target threatened native plant species. If threatened native plant species occur in the proximity of the application site, the following mitigation measure is required to avoid adverse effects: A downwind buffer zone of 275 metres when applied with ground based equipment (using coarse droplets).
Bird risk assessment EPA uses EFSA’s Bird model and Excel© spreadsheets21 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:
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
21 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).
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For acute test:
퐷퐷퐷 표푛푒 푎푝푝푙𝑖푐푎푡𝑖표푛 = 푎푝푝푙𝑖푐푎푡𝑖표푛 푟푎푡푒 (푘푔/ℎ푎) × 푠ℎ표푟푡푐푢푡 푣푎푙푢푒
퐷퐷퐷 푚푢푙푡𝑖푝푙푒 푎푝푝푙𝑖푐푎푡𝑖표푛푠 = 퐷퐷퐷 표푛푒 푎푝푝푙𝑖푐푎푡𝑖표푛 × 푀퐴퐹90
For reproduction test:
퐷퐷퐷 = 푎푝푝푙𝑖푐푎푡𝑖표푛 푟푎푡푒 (푘푔/ℎ푎) × 푠ℎ표푟푡푐푢푡 푣푎푙푢푒 × 푇푊퐴 ∗ × 푀퐴퐹푚푒푎푛
*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 mesotrione for bird acute dietary and reproductive screening assessments is shown in the Table 31 and Table 32 respectively. Table 31: Exposure of birds for acute screening assessment Crop & Short- Application MAF BBCH class Indicator cut No of rate (90th DDD (where species2 value applications (kg/ha) %)4 appropriate)1 (90th%)3
Bare soil (Pre- Small emergence granivorous 0.290 24.7 1.0 1 7.16 application) bird
0.290, 2 Large applications Turf herbivorous 30.5 1.2 2 10.61 at 14 d bird interval
1 EFSA, 2009, Table 5 p27
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2 EFSA, 2009, Table 6 p28
3 EFSA, 2009, Table 6 p28
4 EFSA, 2009, Table 7 p29 Table 32: Exposure of birds for reproduction screening assessment Crop & Mean BBCH class Indicator Application short- MAF Number of TWA4 DDD (where species2 rate (kg/ha) cut (mean)5 applications appropriate)1 value3
Bare soil (Pre- Small emergence granivorous 0.290 11.4 0.53 1 1 1.75 application) bird
0.290, 2 Large applications Turf herbivorous 16.2 0.53 1.4 2 3.49 at 14 d bird interval
1 EFSA, 2009, Table 5 p27
2 EFSA, 2009, Table 10 p34
3 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 33: Measures of exposure and toxicity used in the reproduction assessment Test endpoint used as Short-term Long-term Breeding phase surrogate exposure exposure
Pair formation/
22 breeding site 0.1 x LD50 1 day DDD 21 day TWA DDD selection
Copulation and egg NOAEL for the number of eggs 1 day DDD 21 day TWA DDD laying (5 days pre- laid per hen
22 From acute study.
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laying through end of NOAEL for mean eggshell 1 day DDD 21 day TWA DDD laying thickness
0.1 x LD50 1 day DDD 21 day TWA DDD
NOAEL for proportion of viable Incubation and 1 day DDD 21 day TWA DDD eggs/eggs set/hen hatching
NOAEL for proportion of 3 day TWA DDD 21 day TWA DDD hatchlings/viable eggs/hen
0.1 x LD50 (extrinsic adult) 2 day TWA DDD 21 day TWA DDD
21 day TWA DDD 1 day DDD based on based on chick 0.1 x LD50 (extrinsic juvenile) chick shortcut values of Juvenile growth and shortcut value of 3.8 3.8 and 22.723 survival until fledging and 22.73
NOAEL for proportion of 14 day old juveniles/number of 3 day TWA DDD 21 day TWA DDD hatchlings/hen
21 day TWA DDD 1 day DDD based on based on chick 0.1 x LD50 chick shortcut values of shortcut value of 3.8 Post-fledging 3.8 and 22.73 and 22.73 survival
NOAEL for 14 day old juvenile 3 day TWA DDD 21 day TWA DDD weights/hen
2 from acute study 3 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.
Calculation of TERs TER calculations are detailed in Table 34. Table 34: TER values for acute dietary and reproductive risk assessment – Screening assessment
23 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.
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Toxicity Trigger value Birds type DDD endpoint value TER ratio / Presumption (mg/kg bw/d)
Bare soil (pre-emergence application) 1 application of 290 g/ha
>10 / No concern
>20 / No Acute 7.16 >2000 > 279.2 concern for threatened Small species granivorous bird >5 / No concern
>10 / No Long-term 1.75 LD50/10 = >200 > 114.1 concern for threatened species
Turf, 2 applications of 290 g/ha at 14 days interval
>10 / No concern
>20 / No Acute 10.61 >2000 > 188.4 concern for threatened Large species herbivorous bird >5 / No concern
>10 / No Long-term 3.49 LD50/10 = >200 > 57.4 concern for threatened species
Conclusion for bird risk assessment (screening) Both the acute and chronic screening risk assessment indicates risks below the level of concern to birds from the use of Tenacity Turf Herbicide both as pre-emergence and post-emergence treatment. Mesotrione is not bioaccumulative so no risk assessment for secondary poisoning is necessary for this active ingredient.
Bee risk assessment
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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. Table 35: EEC are calculated for this assessment
Measurement Exposure Exposure estimate Acute effect Chronic effect endpoint# endpoint route (EEC)* endpoint
Foliar application
Individual Application rate (kg Acute contact Contact None survival (adults) ai/ha) x 2.4 µg ai/bee LD50
Application rate (kg Individual Acute oral Chronic adult oral NOAEL Diet ai/ha) x 98 µg ai/g x survival (adults) LD50 (effects to survival or longevity) 0.292 g/day
Application rate (kg Chronic larval oral NOAEL Brood size and Diet ai/ha) x 98 µg ai/g x Larval LD50 (effects to adult emergence, success 0.124 g/day survival)
Soil treatment
Individual Briggs EEC x 0.292 Acute oral Chronic adult oral NOAEL Diet survival (adults) g/day LD50 (effects to survival or longevity)
Chronic larval oral NOAEL Brood size and Briggs EEC x 0.124 Diet Larval LD50 (effects to adult emergence, success g/day survival)
Seed treatment&
Individual Acute oral Chronic adult oral NOAEL Diet 1 µg ai/g x 0.292 g/day survival (adults) LD50 (effects to survival or longevity)
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Measurement Exposure Exposure estimate Acute effect Chronic effect endpoint# endpoint route (EEC)* endpoint
Chronic larval oral NOAEL Brood size and Diet 1 µg ai/g x 0.124 g/day Larval LD50 (effects to adult emergence, success survival)
Tree trunk application**
Individual µg ai applied to tree/g Acute oral Chronic adult oral NOAEL Diet survival (adults) foliage x 0.292 g/day LD50 (effects to survival or longevity)
Chronic larval oral NOAEL Brood size and µg ai applied to tree/g Diet Larval LD50 (effects to adult emergence, success foliage x 0.124 g/day 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.
# 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)
퐸퐸퐶 퐴푐푢푡푒 푅푄 = 퐿퐷50 퐸퐸퐶 퐶ℎ푟표푛𝑖푐 푅푄 = 푁푂퐴퐸퐿 Table 36: Risk to bees
Toxicity Application rate EEC (µg endpoint Trigger value Use scenario RQ (kg ai/ha) ai/bee) value (µg /Presumption ai/bee)
Acute / Adult bees - contact
Turf 0.290 0.696 >9.1 <0.08 < 0.4 / No concern
Acute / Adult bees – diet
Turf 0.290 8.29 >11 <1.32 >0.4 / High risk
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Acute effects on brood, and chronic effects on adults and brood
No assessment possible as no data provided on these toxicity endpoints
Non-target arthropod risk assessment Where limit tests are conducted, a low risk to non-target arthropods can be concluded when the effects at the highest application rate multiplied by MAF are below 50% (ESCORT2 workshop, 2000 – p12)
Calculation of HQs
퐴푝푝푙𝑖푐푎푡𝑖표푛 푟푎푡푒 (푔 표푟mL a.i./ha) × 푀퐴퐹 ∗ 퐼푛 − 푓𝑖푒푙푑 퐻푄 = 퐿푅50 ∗∗
* application rate and LR50 must not differ in their units, i.e. must be related to either formulation or a.i. rates
** Multiple application factor, refer to Appendix V, p 45 of ESCORT 2 Workshop, 2000. MAF = 1 when there is just one application.
푂푓푓 − 푓𝑖푒푙푑 퐻푄 푑푟𝑖푓푡 푓푎푐푡표푟 ∗ 푎푝푝푙𝑖푐푎푡𝑖표푛 푟푎푡푒 × 푀퐴퐹 × ( ) 푣푒푔푒푡푎푡𝑖표푛 푑𝑖푠푡푟𝑖푏푢푡𝑖표푛 푓푎푐푡표푟 ∗∗ = × 푐표푟푟푒푐푡𝑖표푛 푓푎푐푡표푟 ∗∗∗ 퐿푅50
* Overall 90th percentile drift values are presented in Appendix VI , p 46 of ESCORT 2 Workshop, 2000.
** default value of 10
*** default value of 10
MAF (Multiple Application Factor) for 2 applications of Tenacity Turf Herbicide is defined as 1.9.
A drift factor for turf application of 2.38% (based on a minimum drift of 1 m) is used for the off-field exposure calculations, based on recommendations made in ESCORT 2 and SANCO/10329/2002 rev 2 final.
On this basis, the resultant in-field and off-field hazard quotients for Typhlodromus pyri and Aphidius rhopalosiphi are shown in the Table 37 and Table 38. Table 37: In-field HQ values for Typhlodromus pyri and Aphidius rhopalosiphi Application rate LR50 Hazard Trigger Species MAF (g ai/ha) (g ai/ha) Quotient value
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/Presumptio n
Typhlodromus pyri >150 290 1.9 < 3.67 > 2 / High risk
Aphidius rhopalosiphi 159 290 1.9 3.46 > 2 / High risk
Table 38: Off-field HQ values for Typhlodromus pyri and Aphidius rhopalosiphi
/ha) /ha)
50
Species LR (g ai Application rate (g ai MAF Vegetation factor Correction factor Drift distance (m)/% drift Hazard Quotient Trigger value /Presumption
< 2 / Typhlodromu >150 290 1.9 10 10 1/ 2.38 < 0.08 Below s pyri concern
< 2 / Aphidius 159 290 1.9 10 10 1/ 2.38 0.08 Below rhopalosiphi concern
Conclusion for non-target arthropod risk assessments High oral (diet) risks for bees were identified following the application of Tenacity Turf Herbicide. The staff consider that turf is not especially attractive for bees or is an important item as food source. In addition, it should be pointed out that the endpoint determined in oral (diet) test was higher than 11 µg/bee (this was the maximum concentration tested due to problems with solubility of mesotrione in the sucrose solution), therefore the calculations can be seen as an overestimation of the risk to bees.
There were high risk for in-field conditions for non-target arthropods, but risks were below concern for off-field conditions. The staff consider that the off-field conditions represent the most concern for non- target arthropods, therefore no mitigation measures are proposed at this stage. Summary and conclusions of the ecological risk assessment
The EPA staff assessed the potential risk to be triggered by the use of Tenacity Turf Herbicide following the instructions captured in the proposed label and the GAP table.
Aquatic environment The acute and chronic risks for aquatic organisms were below the level of concern for the use conditions of Tenacity Turf Herbicide. There were high risk for aquatic plants. The staff consider that additional controls should be set for this substance.
1) Tenacity Turf Herbicide should not be applied into or onto water;
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2) Tenacity Turf Herbicide can only be sprayed using a low volume ground based with a nozzle set to provide a coarse spray;
3) The maximum application rate of Tenacity Turf Herbicide is 290 g ai/ha, 2 applications per year with a minimum 14 days interval between applications.
4) A buffer zone of 10 meters is set when Tenacity Turf Herbicide is applied downwind to an adjacent water body.
Soil environment Acute and chronic risks for soil organisms were below the level of concern, except for non-target plants. A downwind buffer zone of 15 m is necessary to manage the risks to non-target plants. An advisory buffer zone of 275 m should serve as guidance for the applicators regarding the risks to threatened native plant species.
Effects on vertebrates Risks for birds were below the level of concern.
Effects on invertebrates There were high risks for bees (oral exposure) and for non target arthropods in-field conditions. The staff consider that additional controls concerning the method of application should mitigate the risks.
February 2016