WE have an excellent regulatory process in Australia that regularly reviews data and ensures that modern pesticides are as safe as possible to the user, environment and food markets.
If need be, some products are banned and some may have tighter controls.
It may be easy for some to use examples of harmful pesticides of the distant past but times have changed and the range of products now on the market have passed many stringent hurdles to get access in Australia.
The herbicides we have available today may not be with us forever.
We need to use all our herbicides wisely.
An environmental disaster via poor application or total negligence could trigger a 'cause for concern' by the APVMA and a potential review of that herbicide.
Protecting our herbicides
Is the primary herbicide of choice, glyphosate, under threat of a permanent ban from the federal regulator, the Australian Pesticides and Veterinary Medicines Authority (APVMA)?
This is a possibility if the APVMA conducts a review of the herbicide and deems it inappropriate for use in Australia.
Pesticide reviews are a regular part of business for the APVMA. Reviews have been underway since 1995 and they have a list of candidate pesticides to review and many common herbicides have already been intensively reviewed.
What triggers a need to undertake a pesticide review?
Occasionally, credible new scientific information may be generated after a product has been registered that suggests the existence of previously unknown risks to human health, animal or crop safety, the environment or trade, or that suggests product ineffectiveness.
If this happens, the APVMA can initiate a reconsideration process to assess the identified risk and determine whether changes are needed to ensure that the product can continue to be used safely and effectively.
Common herbicides that have undergone the review process since 1995 include: Atrazine (product name Gesaprim), Diquat (Reglone - review in progress), Diuron (Diurex), Paraquat (Gramoxone - review in progress) and Glyphosate (Roundup).
Moderate restrictions have been put in place for diuron after some environmental concerns.
It appears the APVMA have reviewed many more insecticides than herbicides due to concerns over occupational health and safety and environment.
The APVMA have nominated some herbicides for review in 2017 and 2018; simazine and picloram being targeted.
Picloram is a common active ingredient in Grazon and Tordon products.
Why concern was raised over glyphosate
A few years ago a report from the International Agency for Research on Cancer (IARC) concluded that glyphosate was probably carcinogenic.
This conclusion understandably caught the attention of the media and left the chemical industry, farming community, federal regulators, weed managers and the broader community asking many questions.
Assessment of the IARC report by the APVMA
New studies, assessment reports and scientific opinions on approved pesticides or veterinary medicines are generated regularly and the APVMA evaluates the scientific merits of these before deciding on whether a formal reconsideration -- or other regulatory action -- is appropriate.
The APVMA evaluated the IARC report and other contemporary scientific assessments as part of an established chemical review nomination process.
The APVMA conducted a weight-of-evidence evaluation that included a commissioned review of the IARC monograph by the Department of Health, and risk assessments undertaken by expert international bodies and regulatory agencies.
The APVMA has concluded that glyphosate does not pose a carcinogenic risk to humans and that there are no grounds for changes to its directions of use.
The IARC assessment explained
The IARC assessment looked at the intrinsic toxicity potential or 'hazard' of the chemical glyphosate as a cancer-causing agent only.
Indoor emissions from burning wood and high temperature frying, some shift work, and consumption of red meat are also classified as probably carcinogenic to humans and are in the same category as glyphosate.
Agents classified by IARC in the highest category (carcinogenic to humans) include all alcoholic beverages, consumption of processed meat, solar and ultraviolet radiation (ie sunlight), engine exhaust (diesel), outdoor air pollution, occupational exposure as a painter, and soot and wood dust.
When making an assessment of the hazards associated with these substances or lifestyles they did not consider how the risks can be managed in actual use situations and they did not assess the risk of glyphosate causing cancer when used according to the label instructions in a registered chemical product.
As part of the regulatory process undertaken by the APVMA and pesticide regulators in other countries, a hazard assessment is just one part of the overall risk assessment required to determine the risks for people using a formulated chemical product.
It is not the role of the IARC to consider how a formulated chemical product is used, or how human exposure can be minimised by following safety directions on a product label.
This means the findings of IARC cannot be directly compared to assessments conducted by regulatory authorities for the purposes of approval or registration of a pesticide product - assessments by regulators include consideration of appropriate risk mitigation measures to allow safe use.
Other reviews on glyphosate
To put things into perspective, many expert agencies from various countries have evaluated glyphosate's potential as a carcinogen.
The consensus recommendation is that glyphosate poses no risk of causing cancer that its regulated use (via label directions) will remain.
This is an excellent outcome as many other pesticides have either been banned or their use patterns restricted after the review process.
Countries that have reviewed the use of glyphosate are: Germany, Korea, USA, New Zealand, Australia, Canada, Japan and many European countries.
APVMA website: https://apvma.gov.au/
Once the results of the review of paraquat and diquat are completed, A Good Weed will inform readers of the outcome.
Note: Courtesy of "A Good Weed", a newsletter produced by the Weed Society of New South Wales Inc. Author Tony Cook is Technical Specialist Weeds, Biosecurity NSW, NSW Department of Primary Industries.