Sheep ectoparasiticides review history and regulatory outcomes

Nomination for review

In 1999 the APVMA (formerly the NRA) began a review of selected sheep ectoparasiticides because of concerns over the potential occupational exposure risk from residues on treated wool, the potential for chemical residues to pose a risk to the environment (when released as effluent from wool scour plants) and the concern that residues on wool have the potential to prejudice Australia’s trade, particularly with new environmental standards which take effect in the European Union from October 2007.

In February 2000 the NRA Expert Panel on Organophosphate Sheep Dips (the Panel) reviewed the findings of the UK Institute of Occupational Medicine (IOM) report, Epidemiological study of the relationship between exposure to organophosphate pesticides and indices of chronic peripheral neuropathy, and neuropsychological abnormalities in sheep farmers and dippers (July 1999). The Panel found that work practices and exposure risks differed between Australia and the UK. However, the panel could not completely rule out a link between OP exposure and long-term effects. The panel recommended reducing worker exposure to OPs and that the APVMA (formerly the NRA) review the uses of OPs on sheep.

This review incorporates the findings and recommendations of the Panel and focuses on selected sheep ectoparasiticides for post harvest wool. It does not cover individual animal treatment products, nor does it include active constituents which are only approved for use on short wool (less than six weeks of wool growth).

The review does not consider occupational exposure during application of ectoparasiticides.

A number of active constituents included in the sheep ectoparasiticides review (temephos, propetamphos and diazinon) are also under review by the APVMA in their own right. This is to enable the APVMA to separately assess these active constituents, their uses and any concerns which may or may not include their use as sheep ectoparasiticides. While the active constituent reviews are being conducted separately, the outcomes of the ectoparasiticides review maybe taken into consideration by those reviews.

Preliminary Review Report

In April 2006 the APVMA released the Sheep Ectoparasiticides Preliminary Review Findings Report for public comment. The period for public comments and for the submission of additional information closed on 31 October 2006.

The APVMA concluded that the risks associated with chemical residues in treated wool could generally be reduced by making changes to product labels and use of the products by wool growers.

In the preliminary report the APVMA proposed:

• varying product labels to include
  - a sheep rehandling interval (SRI) statement indicating the interval from application to when the sheep can be safely handled without the need for protective equipment
  - a safety statement advising the use of Personal Protective Equipment (PPE) if sheep are handled during the SRI
  - an advisory statement, ‘Use of this product may result in wool residues that may not comply with European Union Environmental Quality Standards (EQSs) due to be implemented in 2007’
  - a wool harvesting interval (WHI) statement which indicates the minimum interval from when the sheep are treated to when the sheep can be shorn.

The APVMA will issue a final report once the assessment of all available data is completed.

For more information please contact the Chemical Review Program on (02) 6210 4749 or by email to chemrev@apvma.gov.au