Proposed Re-evaluation Decision PRVD2017-03, Lambda-cyhalothrin

Pest Management Regulatory Agency
23 June 2017
ISSN: 1925-0967 (PDF version)
Catalogue number: H113-27/2017-3E-PDF (PDF version)

Summary

Table of Contents

• Executive Summary
  • Health Canada’s Pest Management Regulatory Agency (PMRA)
  • Re-evaluation of Lambda-cyhalothrin
  • Key Findings
  • Next Steps
• Overview
  • What is the Proposed Re-evaluation Decision for Lambda-Cyhalothrin?
  • What Does Health Canada Consider When Making a Re-evaluation Decision?
  • What Is Lambda-cyhalothrin?
  • Health Considerations
  • Residues in Food and Drinking Water
  • Risks in Residential and Other Non-Occupational Environments
  • Occupational Risks
  • Environmental Considerations
  • Value Considerations
  • Proposed Measures to Minimize Risk
  • What Additional Scientific Information Is Requested?
  • Next Steps

Executive Summary

Health Canada’s Pest Management Regulatory Agency (PMRA)

Health Canada’s primary objective in regulating pesticides is to protect Canadians’ health and their environment. Pesticides must be registered by Health Canada’s Pest Management Regulatory Agency (PMRA) before they can be imported, sold, or used in Canada. Pesticides must go through rigorous science-based assessments before being approved for sale in Canada.

All registered pesticides must be re-evaluated by the PMRA on a cyclical basis to make sure they continue to meet modern health and environment safety standards and continue to have value. This may happen sooner if there have been changes in the required information or to the risk assessment methodology. Re-evaluations may result in:

• changes to how products are used;
• changes to product labels to meet current health and environmental standards; or,
• removing products from the market to prevent future harm to health or the environment.

Re-evaluation of Lambda-cyhalothrin

Lambda-cyhalothrin is a synthetic pyrethroid insecticide used to control a broad range of insect pests on a wide variety of sites such as greenhouse food crops, terrestrial food and feed crops, shelterbelts, turf, livestock, structural sites and ornamentals.

When conducting the re-evaluation of lambda-cyhalothrin, the PMRA reviewed scientific information provided by pesticide manufacturers, provinces and Environment and Climate Change Canada, as well as published scientific information. For the environmental assessment, potential risks to organisms on land and in water were examined. For the human health assessment, the following routes of exposure were examined: food, drinking water, exposure when applying the pesticide, and coming into contact with the pesticide after it has been applied.

Key Findings

The human health risk assessment found that there are potential risks of concern from dietary and certain residential exposures to lambda-cyhalothrin. Therefore, cancellation of all food and feed uses and some uses in residential areas are proposed. Exposure from the remaining uses is unlikely to affect your health when used according to the proposed revised label directions.

The environmental assessment found that there are potential risks to pollinators (including bees), beneficial arthropods, mammals, amphibians, aquatic invertebrates and freshwater and marine fish. However, when lambda-cyhalothrin is used according to the proposed revised label directions, it is not expected to pose risks of concern to the environment.

Next Steps

The proposed re-evaluation decision is now open for public consultation for 90 days from the date of Proposed Re-evaluation Decision PRVD2017-03, Lambda-cyhalothrin. PMRA is inviting the public to submit comments on the proposed re-evaluation decision for lambda-cyhalothrin, including proposals that may refine the risk assessment and risk management. Once PMRA considers the comments and any information that are received during the public consultation period, it will publish a final decision.

Overview

What is the Proposed Re-evaluation Decision for Lambda-Cyhalothrin?

The evaluation determined that under the current conditions of use, the human health risks for most products containing lambda-cyhalothrin do not meet current safety standards. Therefore, the PMRA is proposing to cancel the following uses:

Products used by commercial applicators and growers for:

• All uses on food and feed commodities
• Indoor residential uses

An evaluation of the scientific information has determined that certain uses of lambda-cyhalothrin products have value and do not pose risks to human health or the environment. These uses include:

Products used by commercial applicators for:

• Use on shelterbelt, poplar and willow plantings, outdoor gardens, trees and ornamentals
• Structural use in non-residential areas, golf course turf, sod farms and industrial turf
• Use on tobacco

Before making a final re-evaluation decision on lambda-cyhalothrin, the PMRA will accept and consider written comments on Proposed Re-evaluation Decision PRVD2017-03, Lambda-cyhalothrin received up to 90 days from the date of PRVD2017-03, Lambda-cyhalothrin. Please forward all comments to Publications. The PMRA will consider any additional data/information submitted during the consultation period in the final decision.

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

Under the Pest Control Products Act, all registered pesticides must be re-evaluated by the PMRA on a cyclical basis to make sure they continue to meet modern health and environmental safety standards and continue to have value. The re-evaluation considers data from pesticide manufacturers, published scientific reports, information from other regulatory agencies and other available, relevant information. To reach its decisions, the PMRA applies internationally accepted hazard and risk assessment methods and modern risk management approaches and policies.

For more information on how the PMRA regulates pesticides, as well as the assessment process, please visit the Pesticides and Pest Management portion of Health Canada’s website at healthcanada.gc.ca/pmra.

What Is Lambda-cyhalothrin?

Lambda-cyhalothrin is a synthetic pyrethroid insecticide used to control a broad range of arthropod pests on a wide variety of sites including greenhouse food crops, terrestrial non-food, non-feed and fibre crops, terrestrial feed and food crops, shelterbelts, turf, livestock, indoor and outdoor structural sites and surrounding soil, outdoor ornamentals, outdoor wasp and hornet nests.

Lambda-cyhalothrin products can be applied using conventional aerial and ground equipment. They can be applied to cattle as a pour-on or as ear tags. For structural sites, professional applicators can use hand pressurized or power-operated sprayers and pressurized products.

Health Considerations

Can Approved Uses of Lambda-cyhalothrin Affect Human Health?

Risks of concern were identified from dietary and certain residential exposures to lambda-cyhalothrin. Therefore, cancellation of some uses in residential areas and cancellation of all food uses are proposed. Mitigation measures are proposed for non-food uses in non-residential areas. Exposure from the remaining uses is unlikely to affect your health when used according to the proposed revised label directions.

Potential exposure to lambda-cyhalothrin may occur through the diet (food and drinking water), when handling and applying products containing lambda-cyhalothrin, or during contact with treated surfaces. 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.

The dose levels used to assess risks are established to protect the most sensitive human population (for example, children and nursing mothers). Only uses for which the exposure is well below levels that cause no effects in animal testing are considered acceptable for registration.

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. The health effects noted in animals occur at doses which are much higher than levels to which humans are normally exposed when pesticide products are used according to label directions. In addition, for lambda-cyhalothrin, extensive mitigation measures are proposed to further reduce exposures for certain uses.

In laboratory animals, lambda-cyhalothrin ranged from moderate to high acute oral toxicity. Lambda-cyhalothrin is of low to moderate acute dermal toxicity. Lambda-cyhalothrin produced moderate acute inhalation toxicity and slight dermal irritation. Lambda-cyhalothrin caused mild eye irritation, and did not cause allergic skin reactions.

Registrant-supplied short- and long-term (lifetime) animal toxicity tests, as well as information from the published scientific literature, were assessed for the potential of lambda-cyhalothrin to cause neurotoxicity, immunotoxicity, chronic toxicity, cancer, reproductive and developmental toxicity and various other effects. The most sensitive endpoints for risk assessment included effects on the nervous system and reproductive organs. In addition, there was evidence that young animals were more sensitive than adult animals to cyhalothrin toxicity as demonstrated by reduced offspring body weight at a dose which was not toxic to the mothers, as well as other indicators of sensitivity. Longer-term dosing with cyhalothrin resulted in mammary and uterine tumors in mice. Only uses for which the exposure is well below levels that cause no effects in animal testing are considered acceptable for continued registration.

Residues in Food and Drinking Water

Dietary risks from food and drinking water are of concern. In order to address these concerns, cancellation of all registered food and feed uses is proposed, unless there is information/data submitted during the consultation period that would help address the dietary risk concerns identified.

Reference doses define levels to which an individual can be exposed over a single day (acute) or lifetime (chronic) and expect no adverse health effects. Generally, dietary exposure from food and water is acceptable if it is less than 100% of the acute reference dose (ARfD) or chronic reference dose (acceptable daily intake or ADI). An acceptable daily intake is an estimate of the level of daily exposure to a pesticide residue that, over a lifetime, is believed to have no significant harmful effects. For the cancer assessment, a lifetime cancer risk that is less than one-in-a-million (1 × 10-6) is generally considered an acceptable risk for the general population when exposure occurs through pesticide residues in/on food and drinking water, and to otherwise unintentionally exposed persons.

Potential exposure was estimated from residues of lambda-cyhalothrin in both treated crops and drinking water. Exposure to different subpopulations, including children and women of reproductive age, were considered. Food residue estimates were based mostly on monitoring data and included percent crop treated information and chemical-specific processing factors when available. Drinking water estimated environmental concentrations (EECs) were based on the modelling of lambda-cyhalothrin residues in surface water using the typical use rate for turf, which represents the highest outdoor broadcast application rate in Canada.

The acute dietary exposure (from food and drinking water) estimates at the 99.9th percentile for the general population and all other subpopulations range from 364% of the ARfD (children 6-12 years old) to 913% of the ARfD (adults 20-49 years old). The chronic dietary exposure estimates for the general population and all other subpopulations range from 40% of the ADI (youth 13-19 years old) to 115% of the ADI (children 1-2 years old). The dietary cancer risk estimate for the general population is 5 × 10^-6. Thus, acute, chronic and cancer dietary risks from exposure to lambda-cyhalothrin are of concern.

The Food and Drugs Act prohibits the sale of adulterated food; that is, food containing a pesticide residue that exceeds the specified maximum residue limit (MRL). Pesticide MRLs are specified for Food and Drugs Act purposes through the evaluation of scientific data under the Pest Control Products Act. An MRL represents the maximum amount of residues that may remain on food when a pesticide is used according to label directions, and serves as a food safety standard. The Canadian Food Inspection Agency is responsible for monitoring the Canadian food supply for pesticide residues and the determination of compliance with MRLs specified by Health Canada.

Canadian MRLs for lambda-cyhalothrin are currently specified for a wide range of commodities. Residues in all other agricultural commodities, including those approved for treatment in Canada but without a specific MRL, are regulated under Subsection B.15.002(1) of the Food and Drugs Regulations, which requires that residues do not exceed 0.1 ppm. A complete list of MRLs specified in Canada can be found on the PMRA’s MRL Database, an online query application that allows users to search for specified MRLs, regulated under the Pest Control Products Act, for pesticides or food commodities (http://pr-rp.hc-sc.gc.ca/mrl-lrm/index-eng.php). As a result of the re-evaluation, all Canadian MRLs for lambda-cyhalothrin are proposed for revocation and to align with the proposed decision to cancel all registered food and feed uses.

Risks in Residential and Other Non-Occupational Environments

Residential cancer and non-cancer risks from turf postapplication exposures are of concern, therefore mitigation to further limit exposure is proposed.

Residential postapplication exposure may occur while performing activities on or around turf in residential areas treated with lambda-cyhalothrin by commercial applicators. Turf postapplication risks are of concern for children (1<2 years) through hand-to-mouth exposure.

Since risks of concern were identified for children, turf application in residential areas (except golf courses) is proposed for cancellation. Application to non-residential turf is permitted. Proposed label directions will include definitions of residential areas and non-residential areas, with specific examples for each.

Residential cancer and non-cancer risks from outdoor garden and tree postapplication exposures are not of concern.

Residential postapplication exposure may occur while performing activities on or around outdoor gardens and trees in residential areas treated with lambda-cyhalothrin by commercial applicators. Outdoor gardens and tree postapplication risks are not of concern.

Residential cancer and non-cancer risks from indoor structural postapplication exposures are of concern. Therefore, cancellation of all indoor uses in residential areas is proposed.

Residential postapplication dermal and inhalation exposure may occur while performing activities in indoor residential areas treated with lambda-cyhalothrin by commercial applicators. Incidental oral exposure (hand-to-mouth) may also occur for children playing in treated areas.

The following postapplication scenarios were assessed: application for bedbugs, band and spot application, and crack and crevice application. Both cancer and non-cancer risks of concern were identified for all lifestages from dermal exposure for all scenarios except crack and crevice application. Both cancer and non-cancer risks of concern were identified for children from incidental oral exposure for all scenarios including crack and crevice application. Revised label directions are proposed to specify that crack and crevice applications are only permitted in non-residential areas.

All indoor residential applications of lambda-cyhalothrin are proposed for cancellation. Proposed label directions will include definitions of residential and non-residential areas, with specific examples of each. Crack and crevice applications will be defined and specific use directions for these applications will be included.

Aggregate risks are not of concern when the above-noted mitigation is considered.

Aggregate exposure is the total exposure to a single pesticide that may occur from food, drinking water, residential and other non-occupational sources, and from all known or plausible exposure routes (oral, dermal and inhalation).

The aggregate assessment was based on exposures for uses that did not have any risk concerns. For lambda-cyhalothrin, these included exposure from drinking water, and residential exposures from treated gardens and trees and from turf in golf courses.

An aggregate assessment for adults, youth (11<16 years), and children (6<11 years) was conducted based on chronic (background) dietary exposure from drinking water and dermal exposure from gardens and trees, and turf. No risks of concern were identified for all scenarios and lifestages.

Human biomonitoring data were also available and used to inform the risk assessment based on the current registered uses of lambda-cyhalothrin, including food uses. The non-cancer and cancer aggregate assessments using this biomonitoring data also identified risks of concern, supporting the conclusions of the overall risk assessment that risk mitigation is required.

Occupational Risks

Occupational risks to handlers are not of concern for all non-food uses when used according to the proposed revised label directions.

Risks to handlers are not of concern for all non-food scenarios, including use on chokecherry shelterbelt, tobacco, poplar and willow plantings or other outdoor ornamentals, indoor environments, turf in golf courses, sod farms, and non-residential turf. Based on the precautions and directions for use on the original product labels reviewed for this re-evaluation, most risk estimates associated with mixing, loading, and applying activities exceeded target dermal and inhalation margins of exposures (MOEs) and are not of concern with additional personal protective equipment (PPE).

Occupational postapplication risks to workers are not of concern for all non-food uses when used according to the proposed revised label directions.

Postapplication occupational risk assessments consider exposures to workers entering treated sites in agriculture and residential/commercial areas and performing various activities. For all outdoor non-food uses, postapplication risks to workers exceeded target dermal MOEs and are not of concern with the proposed restricted entry intervals.

For indoor structural uses (for example, warehouses, food processing plants) following crack and crevice applications, no risks of concern were identified for postapplication exposure for workers.

Environmental Considerations

What Happens When Lambda-cyhalothrin is Introduced Into the Environment?

Lambda-cyhalothrin is not expected to pose risks of concern to the environment when used according to the proposed revised label directions.

Lambda-cyhalothrin can enter non-target terrestrial and aquatic habitats through spray drift, and aquatic habitats through run-off. In soil and surface waters, it can last for several weeks under certain environmental conditions, breaking down gradually through natural processes. In soil, lambda-cyhalothrin binds strongly to soil particles and is not likely to move downwards through soil towards groundwater. In surface waters, lambda-cyhalothrin tends to move quickly (within hours) to sediments. Lambda-cyhalothrin is rarely detected in groundwater, treated water for drinking, or surface waters such as lakes and rivers. Lambda-cyhalothrin is not likely to enter the atmosphere and be subject to long-range transport.

In laboratory studies, at high concentrations, lambda-cyhalothrin was found to be toxic to pollinators (including bees), beneficial arthropods (parasitic insects and predatory mites), mammals, amphibians, aquatic invertebrates (water fleas and sediment dwelling organisms), and freshwater and marine fish. If lambda-cyhalothrin is used at labelled application rates without any risk reduction measures, it may cause adverse effects on the organisms listed above. Therefore, mitigation measures are proposed in order to reduce potential exposure of non-target organisms and reduce environmental risks. When lambda-cyhalothrin is used in accordance with the proposed revised label directions, it is not expected to pose risks of concern to the environment.

Value Considerations

What is the Value of Lambda-cyhalothrin?

Lambda-cyhalothrin has one of the broadest registered use patterns for the synthetic pyrethroids and is widely used in Canadian agricultural and structural pest management. It is also one of the main alternatives to organophosphates and neonicotinoids, and it is a valuable tool in resistance management. Lambda-cyhalothrin is the only active ingredient registered for suppression of black vine weevils in strawberries, and for control of a number of labeled pests on poplar and willow grown under short rotation intensive culture.

Lambda-cyhalothrin has a role in an Integrated Pest Management approach to manage pests in structural sites. It is used by professional pest control applicators in residential settings to treat bedbugs, cockroaches, and ants.

Lambda-cyhalothrin is important in the control of face flies and horn flies on beef and non-lactating dairy cattle, and the control of lice and ticks on beef cattle and calves as it is an important tool where pesticide resistance is of concern.

Proposed Measures to Minimize Risk

Labels of registered pesticide products include specific instructions for use. Directions include risk-reduction measures to protect human health and the environment. These directions must be followed by law. As a result of the re-evaluation of lambda-cyhalothrin, the PMRA is proposing further risk-reduction measures for product labels.

Human Health

To protect the general population from dietary exposure to lambda-cyhalothrin residues on food, the following requirements are proposed:

• The use of lambda-cyhalothrin on all food and feed commodities is to be cancelled.
• For all food uses (including imports), it is proposed that MRLs be revoked. As this may cause trade conflicts between Canada and other countries, the PMRA will consult with all interested stakeholders before making a final decision on MRL changes.

To protect homeowners, the following requirements are proposed:

• All indoor structural uses in residential areas are to be cancelled.
• All indoor structural applications in non-residential areas are to be limited to crack and crevice applications only.
• Turf application in residential areas is to be cancelled.
• Label directions are to be added clarifying that turf applications are permitted only for golf courses, sod farms, and non-residential areas.
• Label directions are to include definitions of residential and non-residential areas, with specific examples for both outdoor uses and indoor structural uses.
• Definition of crack and crevice application, with specific use directions, is to be included on the label.
• Label statement indicating to apply only when the potential for drift to areas of human habitation or areas of human activity (excluding golf courses) such as houses, cottages, schools and recreation areas including parks, school grounds, and playing fields is minimal, taking into consideration wind speed, wind direction, temperature inversions, application equipment and sprayer settings.

Environment

To protect non-target organisms and reduce environmental risks, the following requirements are proposed:

• Environmental hazard statements will be required for pollinators, beneficial arthropods, mammals, and aquatic organisms. On crops preferred by pollinator species, label statements will advise to avoid application during periods of bloom, or to apply during the evening when bee foraging is minimal.
• Spray buffer zones between the point of application and non-target aquatic habitats will be required.
• Label statements to reduce the potential for runoff will be required.

The proposed mitigation measures are outlined in Appendix XIV of Proposed Re-evaluation Decision PRVD2017-03, Lambda-cyhalothrin.

What Additional Scientific Information Is Requested?

No additional data are required.

Next Steps

During the consultation period, registrants and stakeholder organizations may submit further data that could be used to refine risk assessments (cancer mode of action data, exposure or use information), which could result in revised risk-reduction measures. Stakeholders who are planning to provide information of this type are advised to contact the PMRA early in the consultation period, for advice on studies or information that could be submitted to help refine the relevant risk assessments. Consideration of any additional data/information submitted during the consultation period to further refine the health risk assessment may or may not result in a change to this proposal.

Before making a final re-evaluation decision on lambda-cyhalothrin, the PMRA will consider all comments received from the public in response to PRVD2017-03, Lambda-cyhalothrin. The PMRA will then publish a Re-evaluation Decision that will include the decision, the reasons for it, a summary of comments received on the proposed decision and the PMRA’s response to these comments.