Proposed Re-evaluation Decision PRVD2016-06, Ziram

 

This consultation is now closed.

Pest Management Regulatory Agency
29 February 2016
ISSN: 1925-0967 (PDF version)
Catalogue number: H113-27/2016-6E-PDF (PDF version)

This page is a summary of the consultation document. If you would like to comment, please request the full consultation document.

To obtain a full copy of Proposed Re-evaluation Decision PRVD2016-06, Ziram please contact our publications office.

Should you require further information please contact the Pest Management Information Service.

Summary

Table of Contents

What is the Proposed Re-evaluation Decision?

After a re-evaluation of the fungicide ziram, Health Canada's Pest Management Regulatory Agency (PMRA), under the authority of the Pest Control Products Act and Regulations, is proposing the cancellation of all ziram uses in Canada.

An evaluation of available scientific information found that, under the current conditions of use, ziram products pose potential risks of concern to human health and the environment. Based on the health and environmental assessments, risks of concern were identified for both workers and the general public in addition to birds, mammals and aquatic organisms.

This proposal affects all end-use products containing ziram registered in Canada. Proposed Re-evaluation Decision PRVD2016-06, Ziram is a consultation document that summarizes the science evaluation for ziram and presents the reasons for the proposed re-evaluation decision.

The information in PRVD2016-06, Ziram is presented in two parts. The Overview describes the regulatory process and key points of the evaluation, while the Science Evaluation provides additional technical information on the assessment of ziram.

PMRA will accept written comments on Proposed Re-evaluation Decision PRVD2016-06, Ziram up to 60 days from the date of publication of PRVD2016-06, Ziram. Please forward all comments to Publications.

What Does Health Canada Consider When Making a Re-evaluation Decision?

The PMRA's pesticide re-evaluation program considers potential risks as well as the value of pesticide products to ensure they meet modern standards established to protect human health and the environment. Regulatory Directive DIR2001-03, PMRA Re-evaluation Program, presents the details of the re-evaluation activities and program structure. Re-evaluation draws on data from registrants published scientific reports, information from other regulatory agencies and any other relevant information.

What is Ziram?

Ziram is a contact protectant fungicide registered for both food and nonfood uses. It is registered for control of diseases on apple, peach, apricot, tomato, and cucurbit vegetables as a foliar application; and as a material preservative to prevent bacterial degradation of dry starch and synthetic latex adhesive formulations. The agricultural uses are applied using ground application equipment by growers, farm workers and professional applicators.

Health Considerations

Can Approved Uses of Ziram Affect Human Health?

Based on the human health risk assessment, all uses of ziram are proposed for cancellation.

Exposure to ziram may occur when handling and applying the product in agricultural and industrial settings, entering treated areas, coming in contact with treated materials/products, and through diet. When assessing health risks, two key factors are considered:

  • the levels at which no health effects occur and
  • the levels to which people may be exposed.

Toxicology studies in laboratory animals describe potential health effects from varying levels of exposure to a chemical and identify the dose at which no effects are observed. Unless there is evidence to the contrary, it is assumed that effects observed in animals are relevant to humans and that humans are more sensitive to effects of a chemical than the most sensitive animal species. For ziram, toxicology endpoints from a developmental neurotoxicity study in rats were used for human health risk assessment. Based on the weight of evidence from the available studies, a cancer unit risk value was also established for ziram.

The risk assessment compares the estimated level of human exposure to the no-effect doses identified in the animal tests. The reference values used to assess risks are established to protect the most sensitive human population (for example, children and nursing mothers). The estimated dietary exposure to ziram from domestically produced and imported food commodities exceeded the acute and cancer reference values established from the toxicology. Potential risks of concern were identified for workers handling ziram products during mixing/loading and application as well as from re-entering treated agricultural sites following a single application of ziram. Potential risks of concern were also identified following application of ziram to fruit trees in residential settings and from use of adhesives containing ziram as a preservative.

The ziram health risk assessment has considered the currently registered use pattern and label directions as well as additional mitigation measures such as additional personal protective equipment, engineering controls to reduce exposure, and modifications to the use pattern (for example, reduced application rates and cancellation of certain uses).

Environmental Considerations

What Happens When Ziram is Introduced into the Environment?

The use of ziram poses risks to birds, mammals and aquatic organisms that cannot be fully mitigated.

Ziram can enter nontarget terrestrial and aquatic habitats through spray drift and can enter aquatic habitats through run-off. Ziram transforms quickly to thiram, which is also a registered pesticide. Ziram and thiram are soluble in water and do not vaporize when sprayed on crops. They are nonpersistent in soil and water, and are not expected to move through the soil profile or bioaccumulate.

When exposed to high enough concentrations, ziram is toxic to birds and mammals, which may be at risk if they consume food sources that have been sprayed with this pesticide. Aquatic organisms are also potentially at risk due to exposure to ziram and thiram. The environmental risk assessment considered the currently registered use pattern as well as mitigation in the form of spray buffer zones and label statements highlighting the risk of runoff, however, risks to birds and aquatic organisms cannot be fully mitigated.

Value Considerations

What is the Value of Ziram?

Ziram is registered for control of several economically important diseases on apples, peaches, apricots, cucumbers (field), tomatoes (field), melons, pumpkins and squash. Ziram has a multi-site mode of action. It is used in rotation with other single-site fungicides for resistance management, thus prolongs the effective life of these fungicides which are highly prone to the development of resistance.

Proposed Measures to Minimize Risk

Based on the available data and current risk assessments, Health Canada is proposing cancellation of all uses of ziram. Consequently, all maximum residue limits (MRLs) are proposed for revocation.

Next Steps

The PMRA is inviting stakeholders to submit comments on this document, as well as detailed proposals to further refine the risk assessment and mitigate risks. The PMRA will accept comments and proposals for a period of 60 days from the date of publication of Proposed Re-evaluation Decision PRVD2016-06, Ziram. Please forward all comments to Publications.

Before making a final decision on ziram, the PMRA will consider all comments or proposals received from the public in response to Proposed Re-evaluation Decision PRVD2016-06, Ziram. A science-based approach will be applied in making a final decision on ziram. The PMRA will then publish a re-evaluation decision document, which will include the decision and the reasons for it, a summary of the comments and proposals received on the proposed decision and the PMRA's response to these comments and/or proposals.

If no proposals to refine the risk assessment are received, or if those received are inadequate, then the PMRA will proceed to finalize the re-evaluation decision to cancel all ziram uses in Canada.

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