Chemical residues/MRLs – impact, understanding and potential trade issues

Take home messages

• It is a legal requirement to follow all label directions when applying any chemical.
• There are different perceptions and legal/contractual requirements of key domestic and export markets for chemical residues.
• There are market access implications when using chemicals – applying a chemical according to label directions does NOT necessarily mean that that grain will meet market requirements.
• There is a need for advisers and growers to understand your market and seek advice on the MRLs that apply. Talk to your marketer if possible before you intend to apply chemicals to a crop.

Introduction - what is a maximum residue limit (MRL)?

A range of different types of chemicals are applied to crops for varying reasons. Chemicals may be used prior to planting, during the crop growth stage or following harvest. Only those chemicals registered in Australia for use on a particular crop may be applied. All chemicals registered in Australia must be used according to label directions, e.g. application rates, withholding periods, etc. This is a legal requirement in Australia.

When using these chemicals, residues may arise on the harvested grain. Residues may also arise via contamination. For example, when moving that grain using equipment such as augers and trucks that have previously held grain containing chemical residues.

The nature of residues arising are considered by the Australian Pesticides and Veterinary Medicines Authority (APVMA) and if necessary, an MRL is set for that chemical and crop commodity combination when a chemical is registered for use.

The APVMA defines an MRL as ‘the maximum concentration of a residue resulting from the registered use of an agricultural chemical which is legally permitted or recognised as acceptable to be present in or on a food, agricultural commodity or animal feed’.

Why is chemical advocacy so important these days?

Customers and importing country government regulators have always considered that the chemical residues on the food they are importing and ultimately consuming, needs to be managed. Increasingly there is the perception from some sectors of society that chemicals are a food safety issue when present on food. However, given the large safety margins used when developing MRLs, the MRLs are generally not a food safety issue. However, society’s perceptions  differ.

The current trends in domestic and export markets are as follows:

• MRLs and chemicals in general are being specified in customer contracts.
• Markets are developing their own chemical regulations and are not relying on international standards such as Codex Alimentarius.
• Markets are requiring lower (or nil) residues on grain that is supplied.
• Markets are also increasing their level of monitoring of imported grain via sampling and testing to check compliance with their needs.
• Markets are demanding to know what chemicals were applied to the crop and the residue status of the supplied product. This includes some form of ‘traceability’.

This changing focus places greater scrutiny on Australian grain used domestically or when exported. It places greater pressure on users of chemicals to only use registered products and at the registered label rate. Particular chemicals may be banned from use (and the MRL reduced to a low level or nil) for political rather than food safety issues.

This increased focus can impact on the tools growers have to manage growing a profitable and quality product. It also places greater pressure on marketers to select grain for a market where the Australian MRL may be higher than that applied in the importing country.

If any participant fails in their responsibility, the loss of reputation or worse still, loss of market access, is difficult, if not impossible to overcome.

Do all markets have the same MRLs and where can this information be sourced?

Each market, whether it be in Australia or overseas, is responsible for ensuring the food that is imported and subsequently consumed is safe to eat in terms of chemical residues. Each market has their own chemical legislation based on their own particular chemical usage and food consumption patterns. Hence different MRLs for the same chemical and commodity may apply in each market.

These differences need to be carefully managed when supplying grain. The increase in grain traded internationally may cause a market access issue for Australian grain. For example, there are many instances for a particular chemical and commodity where:

• The market has no MRL.
• The market doesn’t apply the international standard (Codex) MRL.
• There is no Codex MRL for those markets that follow or default to Codex.
• The market does not have a default policy and hence a zero limit applies where they do not have an MRL.
• The market applies a low level of detection when they have no MRL.

Importing country regulations and customer requirements may also vary. It is the responsibility of the marketer of the grain to ensure they know the regulations of their customers and that the grain supplied meets those requirements.

Some key Australian markets and their current chemical MRL regulations are listed in Table 1.

Table 1. Example set of markets and their current chemical MRL regulations

Note: Above is as at 9 July 2020, variations exist for specific chemicals. MRLs quoted in mg/kg.       Std = Standard

GCC = Gulf Cooperation Council             CRA = Country Recognition Agreement (accepts AUS MRL for some commodities)

As an example of the different MRLs that apply, Table 2 shows current MRLs (as at 9 July 2020) for barley in key markets.

Table 2. Example set of markets and the MRLs for chemicals applied to barley.

D = Default      * = LOD   IT = Import Tolerance    T = Temporary     Yellow = under review    Orange = AUS industry agree not to use on malt barley

Given MRL changes are often slow and are developed under a complex system, it can be difficult to understand current and future MRLs at any given point in time. The key is that often you can’t just read an MRL in a table – crop groups and default policies mean the actual MRL may be something different if no MRL is listed.

There is no single source for this information. Information on MRLs must be sourced from various areas, such as:

• Codex
• Each country government website – but MRLs are generally hidden and as generally they are in a foreign language, the information needs translation
• Most countries:
  • Subscription based
  • Government databases
  • MRLs for around the world
  • AUS APVMA MRLs

OR

• Contact myself, Chair NWPGP, whose role is to provide industry with this market access information.

Is it the grower’s responsibility to ensure MRL requirements are met or the grain buyer?

In short, it is the marketer’s responsibility to meet the buyer’s MRLs.

As stated previously, even though a grower may apply a chemical correctly and in accordance with label directions, the resulting grain residues may not meet market requirements.

In addition, a grower does not always know the market or the market requirement before they use a chemical?

However, all grain Trading Standards have wording in relation to chemical use that growers must comply with. An example for the Grain Trade Australia Wheat Trading Standards 2020/21 is outlined below:

“Chemicals not approved for Wheat – a nil tolerance applies, and this refers to the following:

• Chemicals used on the growing crop in the State or Territory where the wheat was grown in contravention of the label
• Chemicals used on stored wheat in contravention of the label
• Chemicals not registered for use on wheat
• Wheat containing any artificial colouring, pickling compound or marker dye commonly used during crop spraying operations that has stained the wheat
• Wheat treated with or contaminated by Carbaryl, Organochloride chemicals, or diatomaceous earth
• Chemical residues in excess of Australian Commonwealth, State or Territory legal limits”

Residue testing is done either by the marketer or by the Australian government National Residue Survey on domestic grain and export grain shipments, the latter funded via a levy on growers. If residues arise that exceed the market MRL, price penalties may occur or the shipment may be rejected and returned to Australia. Costs may be passed from the marketer to the supplier of that grain where there is evidence of chemical mis-use or false chemical use declarations. Sampling and testing of future grower loads and shipments, or additional segregations may be created, all creating costs. These increased costs may be passed onto the grower through the purchase price offered for the grain.

Therefore, at a minimum the post-farm gate sector expects that growers apply chemicals following legal requirements.

Given the expense of sampling and testing all deliveries for all possible chemicals used on-farm, this is not conducted. Rather, targeted sampling and testing is conducted based on market risk. Thus growers must provide accurate information on chemicals used on that crop. Growers are encouraged to complete Commodity Vendor Declarations correctly when details of chemicals used are sought by the trade. Failure to do so risks supply of grain that fails to meet market requirements, a loss in reputation of Australian grain and increased costs for all along the supply chain.

Growers should also show compliance with the regulated chemical use requirements by complying with on-farm stewardship guide “Growing Australian Grain” . That guide shows responsible use of chemicals on-farm.

Grower tools to assist the marketer in meeting market requirements

a) Growers must only use chemicals registered for that crop.

b) It is a legal obligation that growers comply with all label directions, including:

• Rates of application.
• Withholding period.
• Timing for application such as crop development stage.
• A range of other statements such as “DO NOT …………..”.

c) Adopt industry practices such as:

• Compliance with the above listed on-farm stewardship guide.
• Comply with grain trading standards.
• Wherever possible comply with the Australian grain industry Code of Practice where grain is stored onfarm and sold to domestic or export customers direct.
• Correctly complete a Commodity Vendor Declaration form when asked to do so.
• Document chemicals used at all stages on the crop.
• Supply representative samples for residue testing as needed.
• Follow good agricultural practices (for example; integrated pest management (IPM) / resistance management strategies for chemical use).

d) And above all, talk to your buyer (customer) about the MRLs that apply to the product, preferably if possible before applying any chemicals. At a minimum, talk to your adviser about the impact of using particular chemicals and possible impacts on residues arising on that harvested crop. If necessary, seek further advice from technical experts on MRLs that apply in particular markets.

Increased scrutiny on chemical usage

Growers have a good reputation for compliance with Australian chemical regulations and more specifically, label directions. This has enabled successful marketing of grain to existing markets and the ability of the industry to seek alternative markets. However, unfortunately there have been instances where incorrect chemical use (off-label) has been detected discovered via the detection of inappropriate residues on grain to be shipped to a market.

It is recognised that growers have no say in where a marketer may send their grain. However, in the last two years, a greater focus has been placed on providing all sectors of the industry with knowledge of market requirements. This has involved significant communication and liaison with the pre- and post-farmgate sector. The gap between knowledge of the market requirements and what happens on-farm was recognised and communication to the pre-farmgate sector has increased through development of Fact Sheets and presentations to a range of stakeholders throughout Australia. This has occurred via both the Chair NWPGP, GRDC and various government departments. However further communication with the grower and adviser sector will still be beneficial.

Advocacy has occurred on the following key chemicals that have caused or have had the potential to cause some residue issues on Australian grain in recent years:

• Back-loading of Flutriafol treated urea and inappropriate cleaning of trucks
• Introduction of herbicide tolerant varieties and use of that chemistry needs careful management
• Not following application directions on a label and applying the chemical at the incorrect crop growth stage e.g., haloxyfop on canola

In the opinion of the author, the following will face increased scrutiny in the future and may impact on what chemical tools are available for growers:

• Old chemistry, as it generally is no longer supported for various reasons. Where support from a chemical registrant is not gained, following a regulator review of that chemical, the MRLs may be deleted or reduced.
• Desiccants/harvest aids face increased scrutiny given the potential for residues to arise on the harvested crop. Growers should consider limiting their use where possible.
• Aerial application – contamination of nearby crops and the environment in general highlights these practices and they are increasingly being scrutinised by regulators and the public in general. Compliance with legal requirements is essential.
• Fungicides are generally relatively toxic compared to a range of other chemicals. Only use where required.
• Anything with chemical residue carry-over from crop to crop can impact on the subsequent crop. The potential for residue carry-over is scrutinised by regulators.
• Off-label use is not acceptable and does not follow the principle of ‘good agricultural practice’.

Conclusion

Given the changing nature of market regulations, all stakeholders along the supply chain need to be aware of market requirements in relation to MRLs. Given the implications of incorrect chemical use, there is a need for greater transparency and understanding by growers and grower advisers of the impact of chemical use on market access.

Going forward there will be a focus on ensuring all supply chain participants understand the risks of non-compliance with label directions. Reducing gaps in this knowledge, including chemical registrants, re-sellers, agronomists, growers and their advisers, will be a focus of activities.

Growers need to talk to their adviser/agronomist and storage agent/marketer and where needed other experts, to seek advice on current and future market requirements.

Useful resources

On-farm Stewardship Guide ‘Growing Australian Grain’

National Working Party on Grain Protection

National Residue Survey

APVMA

Acknowledgement

This project is undertaken solely as a GRDC project and is made possible by the significant contribution of growers through the support of the GRDC. The author would like to thank growers and the GRDC for their continued support.

Contact Details

Gerard McMullen
Chair, National Working Party on Grain Protection
76 Bruce Street, Coburg, Victoria
0419 156 065
gerardmcmullen@optusnet.com.au