Independent Human Health Risk Assessment for the Lord Howe Island Rodent Eradication Program

In June 2016, the Hon. Mark Speakman MP, Minister for the Environment, requested that the NSW Chief Scientist & Engineer, Professor Mary O’Kane, assist the Lord Howe Island Board (the Board) in undertaking an independent Human Health Risk Assessment (HHRA) in relation to the proposed Lord Howe Island Rodent Eradication Program in line with the Terms of Reference below.


Opportunity to engage with HHRA contractor

The Office of NSW Chief Scientist & Engineer has engaged Ramboll Environ Australia Pty Ltd to undertake the independent HHRA. As part of the process, Ramboll Environ Australia Pty Ltd, along with a representative from the Office of NSW Chief Scientist & Engineer will travel to Lord Howe Island to gather information about Lord Howe Island for the HHRA and to talk to the community. The visit is planned for 8 to 10 November 2016. Further information on the community meeting will be provided by post office box drop.


Public Submissions

In addition to the community meeting, submissions from the public were welcome and made to the Office of the NSW Chief Scientist & Engineer.

Submissions are now closed.


Lord Howe Island Rodent Eradication Program Human Health Risk Assessment Expert Panel - Terms of Reference

The Board is working to implement the Lord Howe Island Rodent Eradication Program. In developing the Program, the Board has committed to commissioning an independent HHRA for the Rodent Eradication Program, and to have the HHRA independently reviewed.

To assist in the process of developing the independent HHRA, the NSW Chief Scientist & Engineer is requested to:

  1. Provide advice to the Board on processes for commissioning the HHRA including identification of suitable experts and scope of the request for proposal
  2. Convene an Expert Panel to review proposals to undertake the HHRA and select a preferred candidate; review project plans and methodologies; and review draft and final reports of the HHRA as required
  3. Provide advice to the Minister for the Environment on the HHRA
  4. Respond to media enquires as they relate to the Terms of Reference for the Expert Panel

Members of the Panel

Professor Mary O'Kane, Chair
Mary O'Kane is the NSW Chief Scientist & Engineer.

Dr Chris Armstrong, Deputy Chair
Chris Armstrong is the Director of the Office of Chief Scientist & Engineer, NSW.

Professor Brian Priestly
Brian Priestly is Director of the Australian Centre for Human Health Risk Assessment (ACHHRA) associated with the Monash University School of Public Health & Preventive Medicine and an Independent Environmental Services Professional.

Emeritus Professor Stephen Leeder
Stephen Leeder is an emeritus professor of public health and community medicine at the University of Sydney. He is also currently chair of the Western Sydney Local Health District Board.


Final Report: July 2017

Executive Summary

At the request of the Minister for the Environment, the NSW Chief Scientist & Engineer commissioned an independent Human Health Risk Assessment for the Lord Howe Island’s proposed Rodent Eradication Program. The Rodent Eradication Program proposes to use the rodenticide brodifacoum, across the island to eradicate both rats and mice. The rodenticide, in the form of Pestoff 20R, would be distributed by aerial baiting, hand distributed, and in bait stations and trays.

Ramboll Environ Pty. Ltd. was engaged to undertake the Human Health Risk Assessment. An Expert Panel was convened to oversee its development and to review the Human Health Risk Assessment.

The Human Health Risk Assessment looked at a number of potential exposure pathways of the rodenticide to humans, including exposure through soil, air (dust), sediment, surface water, tank water as well as food sources such as seafood and locally grown fruits and vegetables. Potential risks from these pathways were then considered for those most sensitive, which included toddlers, school children, pregnant women and adults spending large amounts of time outside.

A quantitative risk assessment of these exposure pathways and population groups concluded that exposure to brodifacoum from all potential sources are below those likely to result in adverse health effects.

The Human Health Risk Assessment also assessed potential exposure due to ingestion of pellets and found that ingestion of one or a few pellets by a child is unlikely to result in observable anticoagulant effects.

While exposure to the rodenticide via the Rodent Eradication Program was not likely to result in adverse health effects, the pathways contributing most to projected exposure included:

  • ingestion of soil
  • ingestion of tank water
  • dermal contact with soil
  • inhalation of airborne dust during aerial operations.

The Human Health Risk Assessment report (the Report) was reviewed by the Expert Panel. The Expert Panel supported the conclusions of the Report noting that while adverse health effects are not expected, identification of the major pathways can allow those concerned with exposure to implementation mitigation strategies.

The Expert Panel noted that community concerns are greater than the scope of the Human Health Risk Assessment. These concerns include issues around health and wellbeing (e.g. anxiety and stress) and the implementation of the Rodent Eradication Program, such as the likelihood of success and possible need to undertake further eradications at a later date. It is clear that the Rodent Eradication Program is a divisive issue for the island, which has potential to affect social cohesion. Enhancement of community consultation and engagement may assist with alleviating some of these concerns, although expert advice or assistance from professionals should be considered to assist with health and wellbeing related concerns.

Planning for the case of the rats re-emerging will be considered through the Lord Howe Island Board’s rodent detection monitoring program. In such a case, measurement and monitoring should enable early intervention, and consideration of other possible approaches. Further, resistance to brodifacoum has been considered and if necessary additional strategies will be implemented to address this issue. Finally, should the Rodent Eradication Program need to be repeated at a later date, new technologies that are currently being researched (including reproductive technologies) may be considered noting that further research and commercialisation is required before being available commercially.

It is understood that other relevant approvals processes will look at environmental outcomes (effect of brodifacoum on non-rodent species), likelihood of success of the eradication, and approval of helicopter operations during the Rodent Eradication Program (Civil Aviation Safety Authority). The results of these approvals and the recommendations of this report will be considered by the Lord Howe Island Board.

The Report on the Human Health Risk Assessment for the Lord Howe Island’s proposed Rodent Eradication Program can be viewed here


Position Paper

The Chief Scientist & Engineer commissioned a position paper on fertility intervention and toxicant technologies for rodent eradication. The paper by Swegen, Gibb and Aitken is available here


Further Information

Lord Howe Island Board – Rodent Eradication