The Grounds were established based on the new information regarding the risks of non-professional use of chlorothalonil-containing substances in the home garden, and this is the focus of the current reassessment. This document contains the staff's review of the effects of the five chlorothalonil-containing formulations used as home-use crop protection fungicides. The hazard classifications of the substances (all are classified as suspected carcinogens while several are classified as acutely toxic by inhalation, corrosive to the eye and/or as suspected mutagens) also raise concerns.
For these reasons, EPA staff believes that it is appropriate to take a precautionary approach in making proposals for reassessment of the approvals for nonprofessional use chlorothalonil formulations. Submissions are invited on the appropriateness and workability of the EPA's proposals to amend the approvals for chlorothalonil and its formulations. Based on the results of the risk assessment, risk mitigation measures were introduced to manage occupational and residential risks.
Supporting documentation
- Scope of reassessment
- Classifications and revisions
- Can you supply up-to-date compositional information for a chlorothalonil-containing substance(s)?
- Assessment of risks and benefits
In June 2015, the Environmental Protection Authority (“EPA”) established the basis to re-evaluate approvals for non-professional use formulations containing chlorothalonil, pursuant to section 62 of the Act. The impacts of changes in the classification of substances containing chlorothalonil have been reviewed by EPA staff. Preliminary proposals for changes in the classification of substances containing chlorothalonil are listed in Table 2.
Summary of revised HSNO classifications for formulations containing chlorothalonil (bold text indicates changes to current classifications). The hazard classification of the chlorothalonil-containing substances will be further reviewed as this information is received and updated hazard classifications will be published in the EPA's Staff Assessment Report. It is always possible that the committee that decides on this application has a different view of the proposed hazard.
Quantitative risk assessment approach
The adverse effects of substances are considered in relation to their toxicity to human health and the environment, and are referred to as risks. The risks associated with chlorothalonil and its formulations were assessed for all stages of the substances' life cycles: from import or manufacture, to transport, storage, use and disposal. Qualitative assessment was undertaken for all life cycle phases except for use, where quantitative assessment was possible.
The risks of adverse effects on human health have been assessed taking into account the anticipated exposures of applicators or bystanders. Additionally, EPA staff has considered the benefits associated with the availability and use of chlorothalonil-based substances. In preparing the risk assessment and proposals for this application, EPA staff considered that it is not appropriate to assume that nonprofessionals will wear appropriate PPE.
Qualitative assessment of human health effects associated with importation, manufacture, transportation and disposal
Quantitative assessment of human health risks associated with chlorothalonil use 4.9. EPA staff have used available data and exposure modelling to estimate the exposure of people to
Can you supply data to demonstrate the levels of chlorothalonil exposure to operators, re-entry
Toolbox of additional controls to mitigate risks
Identification of residual risks with additional controls in place
A detailed summary of the risks associated with the use of chlorothalonil in household pesticides, and the assessment of whether additional risk mitigation measures can sufficiently and practically control these risks, is presented in Table E1 of Annex E. This exercise has shown that there are no risk mitigation measures can reduce risks to negligible levels (Table E1). This assessment indicates that use in residential settings results in significant exposures to non-professional users and other residents that cannot be managed through additional controls.
The numbered notes refer to the explanatory notes in the last column of Table E1 in Appendix E and provide details of the risk mitigation measures considered.
Adverse effects on society and communities
Relationship of Māori to the environment
Proposals
In making these proposals, the staff has considered the risks and benefits that each substance offers. Additionally, staff have taken a precautionary approach where risk assessments have identified significant uncertainty in the level of human exposure. The staff considers that this precautionary approach is consistent with the intent and purpose of the HSNO10 Act to protect the health of people and communities from the effects of hazardous substances.
Employees suggest that if the DMC agrees that these substance approvals should be revoked, then existing stockpiles should be removed within six months of the decision being issued. Employees recognize that based on the outcome of an exposure assessment of the professional use scenario, additional controls may be required for this substance. Based on the proposals for each of the use categories for each of the chlorothalonil substances, the staff proposes the following decisions, as shown in Table 8 below.
Non-professional use must be phased out11 within 6 months, unless industry can demonstrate that non-professional use is safe. Staff would like to reiterate that the proposals may change if additional information can be provided to refine the risk assessment and/or demonstrate that the risks can be adequately and practically managed. However, due to the magnitude of the risks identified and the nature of the patterns of use, the staff believes that no amount of refinement of the risk assessment is likely to be able to sufficiently reduce the identified risks to human health associated with the use of chlorothalonil in homes or housing.
The staff believes that the approval proposed for retention should be assigned the classifications listed in Table 10 and the default substance controls adjusted accordingly to reflect these changes. For the approval (HSR000618) proposed to be retained, additional controls are detailed in Appendix F. Pursuant to section 54 of the Act, submissions must state the reasons for the submission and whether the person making the submission wishes to be heard at a public hearing .
Further information provided in these areas may allow further refinement of risk assessments and resulting proposals.
Data gaps, assumptions or uncertainties in the human health risk assessment Uncertainty in the human health risk assessment
Executive summary
- Background and justification for the reassessment
- Key points
- Regulatory status
- Use pattern
- Quantitative operator risk assessment
- Critical endpoint definition
- Exposure models used for the risk assessment
- Re-entry risk assessment
- Transfer coefficients
- Impact of wearing PPE
- Multiple applications
- Risks to re-entry persons after 24 hours
- Calculation of Re-Entry Intervals (REI)
- Other inputs for the exposure modelling
- Output of human operator spraying exposure modelling
- Outcomes of the operator exposure assessment
- Output of the re-entry exposure assessment
- Outcomes of the re-entry exposure assessment
- Quantitative bystander risk assessment 32
- Critical endpoints definition
- Output bystander (children)
- Outcomes of the bystander exposure assessment
- Review of active ingredients other than chlorothalonil present in the substances to be reassessed
The risk assessment took into account information on the human toxicity of chlorthalonil and the proposed use pattern of the substance and then used models to predict the exposure of humans (users and bystanders). The exposure modeling has only been carried out for the active ingredient chlorothalonil, although a qualitative review of the other active substances present in the substances can be found in section 3.6. For exposure to bystanders (children) and re-entry after 24 hours, staff used a risk assessment approach similar to the approach of the UK Pesticide Safety Directorate.
Transfer coefficients (TC) refer to the amount of contact between a reentrant and the leaves. These are considered to be independent of the active ingredient/product used and depend on the type of culture and the activity performed by the re-entry worker (EUROPOEM, 2002). From this information, the exposure of re-entrants wearing chemical resistant gloves is assessed.
It should be noted that this assumption does not reflect the practice of consumer use. The risk of relapsers 24 hours after the final treatment was calculated using the following equations. TC = transfer coefficient – the standard US EPA value of 5200 cm2/h was used for the estimate H = exposure duration for a typical day (hours) – this was assumed to be 2 hours, which matches the 75th percentile for toddlers playing on grass in the US EPA Exposure Factors Handbook.
TTR = field transferable residue – the US EPA default value of 5%, derived from wet hand transferability studies, was used. SA = surface area of the hands – the assumption used was that 20 cm2 of skin surface is contacted each time a child places their hand in their mouth (this is equal to the palm surface of the three figures and also relates to the other figure. parameter (Freq)) . There is no formulation data on skin absorption for any of the products under review.
Based on the skin sensitizing and eye corrosive properties of the products of all formulations except Tui Disease Eliminator RTU, PPE (protective gloves, eye/face protection) is recommended. The risk of re-entry after 24 hours without gloves is not acceptable for all activities. The AOEL derived for operator and re-entry worker assessment above is also used for the bystander assessment calculations. The interspecies and intraspecies uncertainty factor used to derive the AOEL is sufficient to protect the majority of the population, including children.
Thiophanate methyl
Although thiophanate methyl is present at a slightly higher, or the same concentration as chlorothalonil, the AOEL for chlorothalonil is 9 times lower than that of thiophanate methyl (ie, chlorothalonil is of much greater toxicity). Therefore, the human health risks associated with the use of this substance are expected to be significantly greater from exposure to chlorothalonil than from exposure to thiophanate methyl.
Tau-fluvalinate
Summary and conclusions of the human health risk assessment
Proper PPE (gloves) are recommended if required to reduce risk. In a home use environment, EPA employees do not consider it appropriate to assume that people will wear the correct PPE. The REI interval without gloves would be 26-70 days, EPA staff do not consider it appropriate to assume that a REI interval can be set for home use. The risk quotient (RQ) for a toddler's exposure is more than 39 to 108 times higher than the level of concern (RQ of 1).
There are a significant number of data gaps that have led staff to take a tentative approach to risk assessment. The results of the risk assessment can be revised if more information is provided about the factors listed in paragraph 1.2.9.
Toxicity controls
Exposure Thresholds
Other toxicity controls
Available at http://www.pesticides.gov.uk/uploadedfiles/Web_Assets/PSD/Re-entry%20worker%20guidance_final%20version.pdf Accessed 16/08/2010b. EFSA, 2010 Decision on the expert review of the pesticide risk assessment for the active substance tau-fluvalinate. TNO effective personal protective equipment (PPE); Available at http://www.bozpinfo.cz/priloha/euroshnet_02.pdf.
Glossary of terms
