Diuron review - Frequently Asked Questions

 

What is diuron?
Diuron is a long acting (residual) herbicide that has been registered in Australia for more than 20 years.

How does it work?
Diuron kills weeds by inhibiting the process of photosynthesis, this means that plants cannot convert sunlight energy to grow. It is absorbed by the plant via the root system.

What is it used for?
In Australia there are currently 88 registered products containing diuron. Diuron is used to kill weeds both before and after emergence. Most of the uses are in agriculture to control all types of weeds in sugarcane, cotton, broadacre crops (oats, wheat, barley), citrus and some horticultural crops such as pineapples and bananas. It is also used to control weeds in irrigation channels and drainage ditches. Diuron is used as a component of anitifouling paints, to protect boats from marine growth, in home aquariums and ponds to prevent algal growth and for weed control around buildings, railway lines, sheds and driveways.

Why is diuron being reviewed?
The active constituent diuron, product registrations containing diuron and associated label approvals are under review as part of the APVMA chemical review program. Diuron was selected for review because of concerns of potential environmental contamination of waterways as a result of diuron run-off from agricultural areas, particularly into marine environments. There were also some human health concerns about the toxicity of some impurities in the active constituent.

How was the review conducted?
In undertaking the review the APVMA received information from a number of sources including scientific data packages submitted by registrants, submissions received from the public, published literature and international reports.

In evaluating the information and preparing the recommendations of the review, the APVMA received advice from the Office of Chemical Safety in the Department of Health and Ageing and the Department of the Environment and Heritage. Advice was also received from state government agencies.

What did the APVMA find in its review?
The key preliminary findings of the review that have lead to the APVMA’s proposed recommendations were that:
· the toxic impurities in the active constituent diuron at the current very small concentration levels do not pose a risk to human heath;
· there is a risk to the environment caused by diuron in water and soil run-off from use in sugarcane, cotton, citrus, horticultural crops and in irrigation channels and drainage ditches;
· the risk to the environment can be reduced by decreasing the environmental load (through reducing application of diuron)
· product labels do not contain instructions for spray drift buffers.
What are we proposing to do about it?
At this stage the APVMA is seeking comment on the preliminary findings and proposed actions in the report. It is now the opportunity for interested parties to comment on the proposed review outcomes and provide any additional information that they consider relevant to the review. Once the public comment period is completed, all submission will be considered prior to finalising the review and implementation of the final recommendations.

The APVMA is considering possible interim action in relation to use of diuron in sugarcane. The exact details of any action to be taken is still being developed in consultation with registrants, expert agencies, states and the sugar industry.

Why has the APVMA made these recommendations?
The APVMA has made these recommendations to ensure that the continuing use of products containing diuron does not present an undue risk to public health and safety or to the environment.

What this will mean for the user?
The recommended findings of the review, if implemented, would have the following impacts:

· Home garden – Current labels allow use in home aquariums and ponds; there would be no changes made and products can continue to be used in this way.
· Commercial situations – The uses of diuron on most broadacre crops would not be affected and could continue to be used. The use of diuron in sugarcane, cotton, citrus and horticultural crops would require a reduction in the amount of product used; altering the label rate and changing agricultural practices may achieve this. The use of diuron in irrigation channels and drainage ditches would not continue.

What is happening overseas?
· The United Kingdom Advisory Committee on Pesticides reviewed antifouling use of diuron in 2000 and revoked the use of diuron on all vessels due to environmental and human health concerns (Advisory Committee on Pesticides (ACP), 2002 and ACP 2000). Significant levels of diuron were detected in water and sediment throughout UK estuary and coastal sites as well as freshwater sites.
· The US EPA conducted a review of diuron under its Reregistration Eligibility Decision [RED] program and published a draft RED environmental report for comment in March 2003. The US EPA review concluded that diuron is stable to hydrolysis and photolysis, is very persistent on soil and does not readily degrade. It is moderately mobile and has been found in both surface and ground waters. There were no final recommendations at this stage to change diuron use patterns, as the assessment is not complete.
· Diuron was to be reviewed in the second stage of the European Union (EU) review program that was considering all chemicals registered in the EU before 26 July 1993. The data submission for the second stage of the EU review closed on 30 April 2002. The review is to be conducted by the Danish agricultural chemical regulator. A final report is not yet available.

How can the public Comment?
A copy of the Preliminary Review Findings report can be found on the APVMA website.

Comments need to be received by 30 September 2005 and can be made either by email chemrev@apvma.gov.au or by direct mail to the APVMA:
Evaluator, Diuron Review
Pesticides Review
Australian Pesticides and Veterinary Medicines Authority
PO Box E240
KINGSTON ACT 2604
Australia

BACKGROUND

What is the Australian Pesticides and Veterinary Medicines Authority (APVMA)?
The APVMA is the Australian Government statutory authority responsible for the regulation of pesticides and veterinary medicines up to the point of retail sale. All pesticides and veterinary medicines must be registered by the APVMA prior to being supplied, sold or used throughout Australia. Pesticides include products that are used around the home garden and those used for commercial or agricultural purposes.

What is product registration?
Registration means that the pesticide or veterinary medicine has been rigorously assessed to ensure that it works, is safe for people, animals and the environment, has been manufactured to appropriate standards and does not pose an unacceptable risk to Australia’s trade with other countries.

All registered products have an approved label that includes instructions for correct use and relevant safety information. Only registered products have a distinguishing number on the label APVMA Approval no. xxxxx/ or NRA Approval No. xxxxx/.

What is a chemical review?
The APVMA has a program for reconsidering (reviewing) the registration of older chemicals that are currently on the market. Reviews are undertaken when there is new information that raises potential concerns about a chemicals ongoing use, suggesting that its registration should be reassessed. This is the process undertaken for products containing diuron.

Reviews can be triggered by new research or other evidence that has raised concerns about one or more of the following:
· the safety of people using the chemical or the product;
· an effect that is harmful to public health;
· an unintended effect that is harmful to animals, plants or to the environment;
· a prejudice to trade or commerce between Australia and places outside Australia;
· whether the product is effective when used as instructed by the label; and
· adequacy of label instructions for the safe and effective use of the product.

When the APVMA decides to reconsider the registration of a chemical it will call for any relevant new information from registrants and the public, it may also require registrants to conduct new studies. The APVMA then assesses all of the available information and publishes a review report that details its findings. The assessment also forms the basis for decisions about the future availability of the chemical or how it is used.

There are three possible outcomes from a review:
· The APVMA is satisfied that products are safe and effective and the chemical use can continue based on existing instructions;
· The APVMA has identified that some aspects of the chemical or its use may not be safe and therefore makes changes to the conditions of registration and/or the label instructions; or
· The APVMA is not satisfied that continued use of the chemicals will be safe and effective and suspends or cancels the chemical.