Dichlorvos Final Review Report and Regulatory Decision
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DICHLORVOS FINAL REVIEW REPORT AND REGULATORY DECISION The reconsideration of the active constituent dichlorvos, registrations of products containing dichlorvos, and approvals of their associated labels MARCH 2011 © Commonwealth of Australia 2011 This work is copyright. Apart from any use permitted under the Copyright Act 1968, no part may be reproduced without permission from the Australian Pesticides and Veterinary Medicines Authority. Requests and inquiries concerning reproduction and rights can be made to: The Manager, Public Affairs Australian Pesticides and Veterinary Medicines Authority PO Box 6182 KINGSTON ACT 2604 Australia Email: [email protected] This document is published by the APVMA. In referencing this document the APVMA should be cited as both author and publisher. ISBN: 978-0-9870591-2-3 Website: This publication is available from the APVMA website: <http://www.apvma.gov.au> Comments and enquiries may be directed to: Manager, Chemical Review Pesticides Program Australian Pesticides and Veterinary Medicines Authority PO Box 6182 KINGSTON ACT 2604 Australia Telephone: +61 2 6210 4700 Fax: +61 2 6210 4776 Email: [email protected] i DICHLORVOS REVIEW − FINAL REVIEW REPORT AND REGULATORY DECISION FOREWORD The Australian Pesticides and Veterinary Medicines Authority (APVMA) is an independent statutory authority with responsibility for the regulation of agricultural and veterinary chemicals in Australia. Its statutory powers are provided in the Agvet Codes scheduled to the Agricultural and Veterinary Chemicals Code Act 1994. The APVMA can reconsider the approval of an active constituent, the registration of a chemical product or the approval of a label for a container for a chemical product at any time. This is outlined in Part 2, Division 4 of the Agvet Codes. A reconsideration may be initiated when new research or evidence has raised concerns about the use or safety of a particular chemical, a product containing that chemical, or its label. The reconsideration process includes a call for information from a variety of sources, a review of that information and, following public consultation, a decision about the future use of the chemical or product. The information and technical data required by the APVMA to review the safety of both new and existing chemical products must be derived according to accepted scientific principles, as must the methods of assessment undertaken. In undertaking reconsiderations (hereafter referred to as reviews), the APVMA works in close cooperation with advisory agencies including the Office of Chemical Safety and Environmental Health within the Department of Health and Ageing, the Department of Sustainability, the Environment, Water, Population and Communities, and the state departments of agriculture, as well as other expert advisers as appropriate. The APVMA has a policy of encouraging openness and transparency in its activities and community involvement in decision-making. The publication of review reports is a part of that process. The APVMA also makes these reports available to the regulatory agencies of other countries as part of bilateral agreements. The APVMA recommends that countries receiving these reports will not utilise them for registration purposes unless they are also provided with the raw data from the relevant applicant. The basis for the current reconsideration is whether the APVMA is satisfied that continued use of the active constituent dichlorvos and products containing dichlorvos in accordance with the instructions for their use: • would not be an undue hazard to the safety of people exposed to it during its handling; and • would not be likely to have an effect that is harmful to human beings; and • would not be likely to have an unintended effect that is harmful to animals, plants or things or to the environment; and • would not unduly prejudice trade or commerce between Australia and places outside Australia. The APVMA also considered whether product labels carry adequate instructions and warning statements. This document, Dichlorvos Final Review Report and Regulatory Decision: The reconsideration of approvals of the active dichlorvos, registrations of products containing dichlorvos and their associated labels, relates to all products containing dichlorvos that were nominated for review by the APVMA. The review’s findings and regulatory decision are based on information collected from a variety of sources. ii FOREWORD The information and technical data required by the APVMA to review the safety of both new and existing chemical products must be derived according to accepted scientific principles, as must the methods of assessment undertaken. The Dichlorvos Final Review Report and Regulatory Decision containing the APVMA’s assessment (including the technical reports for all registrations and approvals relating to dichlorvos) is available from the APVMA website at < http://www.apvma.gov.au/products/review/index.php>. iii DICHLORVOS REVIEW − FINAL REVIEW REPORT AND REGULATORY DECISION OVERVIEW The Australian Pesticides and Veterinary Medicines Authority (APVMA) has completed its review of the active constituent dichlorvos and all products containing dichlorvos and their associated approved labels. Dichlorvos is an organophosphorus insecticide first synthesised in the late 1940s, having been first described as an impurity of the organophosphorus insecticide trichlorfon, . Commercial production of dichlorvos began in 1961. Insects are killed by interference with an enzyme (cholinesterase) in the nervous system, resulting in muscle paralysis. Dichlorvos is commonly used in Australia against a large variety of insects that infest domestic, public and commercial buildings, recreational areas, abattoirs, wineries (non-food producing areas), animal houses, mushroom growing facilities, glasshouses, greenhouses and food storage areas. The major use of dichlorvos is as a disinfestant fumigant or spray for stored grain and for grain handling equipment. There is one veterinary use as an oral paste for the treatment of worms and Bot fly larvae in horses. Other formulations include slow-release strips (e.g. pest-strips), sprays and fumigants. The field use of dichlorvos is limited to the control of leaf roller on avocados. The APVMA decided to review dichlorvos because of specific concerns about its high acute toxicity and its carcinogenic potential. The review began in December 1996. In June 2000 the APVMA released a dichlorvos draft review report (now called the Preliminary Review Findings (PRF) report) for public consultation. A large amount of additional toxicological data became available following the initial PRF and a subsequent PRF was released in June 2008. This document, The reconsideration of the active constituent dichlorvos, registrations of products containing dichlorvos and approvals of their associated labels, summarises the revised assessments and the regulatory outcomes of the dichlorvos review. All public comments received since the release of the PRF report have been considered in the preparation of this report. iv TABLE OF CONTENTS TABLE OF CONTENTS FOREWORD II OVERVIEW IV TABLE OF CONTENTS V ACRONYMS AND ABBREVIATIONS VIII EXECUTIVE SUMMARY 1 Introduction 1 Review findings 2 Toxicological assessment 2 Occupational health and safety assessment 3 Residues assessment 4 Environmental assessment 7 Public submissions 10 Final review outcomes 10 Interim use and additional data requirements 11 Cancellation as a consequence of review findings 12 1 INTRODUCTION 13 1.1 Regulatory status of dichlorvos in Australia 13 1.2 Reasons for the dichlorvos review 13 1.3 Scope of the review 13 1.4 Regulatory options arising from a review 15 2 APPROVED DICHLORVOS USE PATTERNS 16 3 ACTIVE CONSTITUENT ASSESSMENT 19 3.1 Identity and properties 19 3.2 Composition of dichlorvos active constituent 19 4 SUMMARY OF DATA ASSESSMENTS 20 4.1 Toxicology 20 4.1.1 Mechanism of mammalian toxicity 20 4.1.2 Metabolism and toxicokinetics 20 4.1.3 Percutaneous absorption 20 4.1.4 Acute toxicity 21 4.1.5 Repeat-dose toxicity 21 4.1.6 Genotoxicity 21 4.1.7 Carcinogenicity 21 4.1.8 Reproductive and developmental toxicity 22 4.1.9 Neurotoxicity 22 4.1.10 Toxicity to humans 23 4.2 Human exposure to dichlorvos 23 4.3 Dose levels relevant for risk assessment 24 4.3.1 Dose levels relevant for the risk assessment of domestic use 24 4.3.2 Dose levels relevant for occupational health and safety (OHS) assessment 25 v DICHLORVOS REVIEW − FINAL REVIEW REPORT AND REGULATORY DECISION 4.3.3 Dose levels relevant for health and safety assessment of building occupants 27 4.3.4 Dose levels relevant for dietary risk assessment 27 4.4 Risks from domestic uses of dichlorvos 29 4.4.1 Characteristics of dichlorvos pest strips 29 4.4.2 Assessment of risk from residential uses 32 4.5 Occupational health and safety (OHS) 33 4.5.1 Consideration of use patterns on product labels 34 4.5.2 NOELs for occupational health and safety assessment 38 4.5.3 Estimation of occupational exposure and risk 38 4.5.4 Re-entry and re-handling intervals 53 4.6 Residues 55 4.6.1 Cereal grains 57 4.6.2 Pulses 59 4.6.3 Potatoes 60 4.6.4 Mushrooms 60 4.6.5 Avocados 60 4.6.6 Greenhouse and glasshouse crops 60 4.6.7 Horses 61 4.6.8 Animal housing and pens 61 4.6.9 Silo treatment 61 4.6.10 Residues in food from use of dichlorvos pest strips and residual sprays 61 4.6.11 Dichlorvos residues resulting from trichlorfon use 62 4.6.12 Other commodities 64 4.6.13 Animal transfer studies 64 4.6.14 Animal feed commodities and animal