Interim review report
In November 1997, the APVMA released the Atrazine interim review report. The report found that there were no major toxicological concerns with atrazine’s active constituent and that the use of atrazine products posed no undue hazard to most users. New conditions for the use of atrazine were implemented to reduce chemical handling by workers and to reduce drift and run-off into water bodies. The changes included:
- the cancellation of industrial and non-agricultural uses of atrazine, including home-garden uses (cancellation of sale and supply of these atrazine products took effect from 31 December 1998; the application of existing stocks was allowed to continue until 30 June 1999)
- the inclusion of more extensive safety instructions on product labels to reduce chemical handling by workers, spray drift and run-off into water bodies
- the deletion of MRLs for commodities for which there were no current use patterns (citrus, grapes and pineapples).
The APVMA found that additional environmental and residue information was required, and registrants were given up to three years to generate these data. Assessment of the data led to the development and publication of a draft final report.
At the same time as the interim review was released, restrictions on the use of atrazine were introduced in response to detections of atrazine in water bodies and to minimise any further potential risks to the environment. The restrictions were:
- no mixing/loading or application within 20 metres of any well, sinkhole or intermittent or perennial stream
- no application within 60 metres of natural or impounded lakes or dams
- no use in channels and drains
- a maximum annual rate of application of 3 kilograms active ingredient per hectare (kg ai/ha) in all crops except plantation forestry (in which the maximum rates are limited to 4.5 kg ai/ha per year in sandy soils and soils defined as ‘highly erodible’, and 8 kg ai/ha per year in clay loams and heavier textured soils).
These restrictions remain in force.
Draft final review report
In April 2002, the APVMA released the Atrazine draft final review report for public comment. At that time, a number of newly published overseas studies raised additional concerns that atrazine might cause developmental and reproductive problems in frogs. Because of those concerns, the APVMA delayed finalisation of the review in order to investigate the claims and reassess the toxicological and environmental risks of using atrazine.
Second draft final review report
In October 2004, the APVMA released the Atrazine second draft final review report. The report considered all regulatory action taken since the release of the 1997 interim report recommendations, new residues and environmental data, and assessments of the United States EPA frog studies.
The APVMA found that atrazine was unlikely to have an adverse impact on amphibians at existing levels of exposure. However, it concluded that the issue of atrazine and amphibians should be revisited if additional data demonstrated that atrazine posed a hazard to frog populations at realistic levels of exposure.
The APVMA also found that atrazine does not pose a risk to human health, but that the use of products containing atrazine in non-agricultural situations might pose a risk to the environment. Changing the use instructions on product labels would reduce or eliminate those risks.
The APVMA was satisfied that varying product labels and approvals would ensure that atrazine products would continue to meet the requirements for continued registration and use in Australia.
In the 2004 report, the APVMA proposed amending product labels to include:
- a larger buffer zone and additional precautionary statements
- a new withholding period of 28 days for grazing on all crops except canola
- details for reporting incidents of herbicide resistance or breakdowns in efficacy.