Application for the Reassessment of a Hazardous Substance Under Section 63 of the Hazardous Substances and New Organisms Act 1996
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Application for the Reassessment of a Hazardous Substance under Section 63 of the Hazardous Substances and New Organisms Act 1996 Methylarsinic acid and its formulations Application Number: HRC08006 Applicant: Chief Executive ERMA NEW ZEALAND February 2009 Signed:______________ Date:________ Contents Executive Summary 7 Section One – The Application 9 1.1 Applicant details 9 1.2 Background to the application 9 1.3 Preparation of the application 10 1.4 Notification and consultation 11 1.5 Substance(s) covered by the application 11 Section Two – The Risk Management Context 12 2.1 Risk management context 12 2.2 Identification and assessment process 12 2.3 Consideration of uncertainty 13 2.4 Ethical considerations 14 2.5 Principles of the Treaty of Waitangi (Te Tiriti ō Waitangi) 16 2.6 Discussion of scenarios 16 Section Three – The Substance and its Lifecycle 18 3.1 Identification of the substance(s) 18 3.2 Mode of action 18 3.3 Review of hazardous properties 19 3.4 Lifecycle and use of MSMA 19 3.5 NZ usage 21 3.6 International usage 23 3.7 Existing Controls 24 Section Four – Identification and Assessment of Adverse and Positive or Beneficial Effects (Risks, Costs and Benefits) 25 4.1 Introduction 25 4.2 Environment 25 4.3 Human health and safety 28 4.4 Society and the market economy 32 4.5 Māori interests and concerns 38 4.6 International obligations 38 Section Five – Likely Effects of MSMA Being Unavailable 39 MSMA Reassessment – Application February 2009 Page 3 of 272 Section Six – Overall Evaluation 42 Section Seven – Recommendations 45 7.1 Use of environmental user charges to reduce adverse effects 45 7.2 Agency recommendation 45 Appendices 46 Page 4 of 272 February 2009 MSMA Reassessment – Application List of Appendices Appendix A: Chemical and physical properties of the active ingredient 46 Appendix B: Alternative Substances and Management Options to the use of MSMA 51 Appendix C: Environmental Assessment report. AOEL 65 Appendix D Significance of MSMA in the New Zealand Environment 114 Appendix E: Review of human toxicology and setting of an AOEL 120 Appendix F: Human Exposure Modelling MSMA 195 Appendix G: Qualitative Descriptors for Risk/Benefit Assessment 252 Appendix H: Current Controls 258 Appendix I: Overseas Regulatory Action 264 Appendix J: Parties consulted pre-application 266 Appendix K: Submission received 267 Appendix L: References 269 List of Tables Table 1: Substances covered by this application 11 Table 2: MSMA use scenarios 16 Table 3: Alternative products and techniques to replace MSMA 17 Table 4: Identity of Methylarsinic acid and its sodium salt 18 Table 5: Classification of MSMA 19 Table 6: Description of manufacture, importation, transport, storage and disposal of formulations of MSMA 19 Table 7: Rates for use of AGPRO MSMA 600 (a.i. 600gm/litre) 20 Table 8: Identification of potential sources of risk 25 Table 9: Conclusions of the environmental risk assessment 26 Table 10: Conclusions of the occupational risk assessment 29 Table 11: Identification of potential effects on society and the market economy 32 Table 12: Assessment of adverse effects on society and the market economy 32 Table 14: Identification of beneficial effects on society and the market economy 35 Table 15: Comparison of alternative treatments for the management of paspalum and kikuyu in turf 39 Table 16: Summary of options for paspalum and kikuyu management 41 Table A1: Summary of Chemical Identity 46 MSMA Reassessment – Application February 2009 Page 5 of 272 Table A2: Generic terms used in relation to arsenic 47 Table A3: Details of specific arsenic compounds mentioned in the assessments 47 Table A4: Physico-chemical properties of the active ingredient (Source US EPA 2006) 49 Table A5: Physico-chemical properties of AGPRO MSMA 600 (Information supplied to ERMA New Zealand by the importer) 50 Table B1: MSMA use on Turf in New Zealand 51 Table B2: Non chemical management for species controlled by MSMA 52 Table B3: Alternative Chemical controls for species controlled by MSMA 53 Table B4: Trade names of herbicides listed in Table B2 54 Table B5: Hazard ratings for pesticides available in New Zealand that provide alternative controls to MSMA 55 Table B6: Comparison of alternative treatments for the control of paspalum and kikuyu in turf 60 Table B7: Summary of options for paspalum and kikuyu management 62 Table D1: Guidelines for maximum acceptable value of Arsenic and indicative background levels of Arsenic in the environment 115 Table D2: Comparison of the sum of environmental and MSMA derived arsenic with MFE guidelines – all figures shown are 116 Table D3: Scenario 1 modelling results for total soil arsenic in relation to MFE guidelines 117 Table G.1: Magnitude of adverse effect (risks and costs) 253 Table G.2: Magnitude of positive effect (benefits) 254 Table G.3: Likelihood 255 Table G.4: Level of risk 255 Table G.5: Assignment of level of risk/benefit 256 Table G.6: Levels of concern and qualitative level of risk used in the environmental risk assessment for aquatic organisms 256 Table G.7: Levels of concern and qualitative level of risk used in the environmental risk assessment for terrestrial organisms 257 Table H1: Existing controls for MSMA and its formulations 259 Page 6 of 272 February 2009 MSMA Reassessment – Application EXECUTIVE SUMMARY Preliminary recommendations ERMA New Zealand proposes that the existing approvals for methylarsinic acid and its sodium salt (MSMA) should be revoked. This recommendation is made on the basis that the risks associated with the use of methylarsinic acid and its sodium salt in New Zealand outweigh the limited benefits of use so far identified. The key risks of concern identified in this application relate to the persistency of arsenic, its potential to accumulate in the environment and to impact over the long term on human health. However, in making this recommendation ERMA New Zealand recognises that the risks, costs and benefits are finely balanced and that the recommendation reflects the precautionary approach required under the Act where there is scientific and technical uncertainty about effects. In the case of methylarsinic acid and its sodium salt, the main area of uncertainty arises from the lack of data on the chronic effects in the environment and detailed information on the fate of organic and inorganic arsenic in soil and groundwater over time. The application The Chief Executive of ERMA New Zealand is seeking the reassessment of the existing approvals relating to methylarsinic acid and its sodium salt under section 63 of the Hazardous Substances and New Organisms Act 1996 (―the Act‖). ERMA New Zealand proposes that the existing approvals for methylarsinic acid and its sodium salt (MSMA) should be revoked. This recommendation is made on the basis that the risks associated with the use of methylarsinic acid and its sodium salt in New Zealand outweigh the limited benefits of use so far identified. The key risks of concern identified in this application relate to the persistency of arsenic, its potential to accumulate in the environment and to impact over the long term on human health. However, in making this recommendation ERMA New Zealand recognises that the risks, costs and benefits are finely balanced and that the recommendation reflects the precautionary approach required under the Act where there is scientific and technical uncertainty about effects. In the case of methylarsinic acid and its sodium salt, the main area of uncertainty arises from the lack of data on the chronic effects in the environment and detailed information on the fate of organic and inorganic arsenic in soil and groundwater over time. Methylarsinic acid and its sodium salt are organic arsenical-based herbicides that are used in New Zealand to control paspalum and kikuyu in fine turf growing north of Taupo. Two approvals for methylarsinic acid and its sodium salt have been granted under the Act, one for methylarsinic acid (approval number HSR003391)and one for the sodium salt as a soluble concentrate containing 600g/l of methylarsinic acid (approval number HSR000538). There is currently one product, AGPRO MSMA 600, a soluble concentrate of the sodium salt, used on turf in New Zealand. Approval for use of methylarsinic acid, its sodium salt and other organic arsenical pesticides has been withdrawn in the European Union and Canada. The United States is MSMA Reassessment – Application February 2009 Page 7 of 272 preparing to initiate cancellation proceedings for the re-registration of all arsenical pesticides. Overseas reviews and subsequent actions were based on concerns of increasing arsenic levels in soil and groundwater due to repeated use of the product. Eco-toxicological assessment of methylarsinic acid and its sodium salt has identified acute risks, associated with its use, to aquatic plants, non-target plants outside the treatment area and birds. Risk mitigation measures can be used to reduce acute risks to an acceptable level for aquatic and terrestrial plants but low level acute risks to birds cannot be mitigated. Data on chronic effects is lacking for all parts of the environment making it impossible to assess the long term effects of methylarsinic acid and its sodium salt on the environment. In view of the persistency of arsenic and its potential to accumulate within an environment this uncertainty represents a significant risk. Human health assessment of methylarsinic acid and its sodium salt has identified acute risks in terms of eye irritation and low level acute toxicity. Risk mitigation measures for operators can be used to reduce these risks to an acceptable level. Modelling based on total arsenic has identified long term unacceptable non cancer risks to all those involved in high contact activities on treated areas and the potential for increased cancer rates in children who have played on treated areas and adjoining properties over a number of years.