PFAS pesticides on our berries

Isocycloseram – an emerging threat

Imagine you’re driving downhill and the accelerator jams. You’re going faster and faster, you pump the brakes, but the brakes have also stopped working.

That is, in effect, what a relatively new insecticide called isocycloseram does to an insect’s nervous system: it jams the nerves’ off switch, so they keep firing until the insect is paralysed and dies. More technically, it targets the insect’s GABA-gated chloride channel – the tiny gate that normally lets a nerve calm down after it fires.

It won’t surprise you to learn that humans have the same GABA gate system.

Australia: first to approve, last to ban

Isocycloseram was approved in Australia in 2021, with the first product registered in 2022. It is made by Syngenta – the same manufacturer behind paraquat who is facing thousands of lawsuits around the world alleging the company knew of links to Parkinson’s disease and concealed them.

The Australian Government was one of the first in the world to approve isocycloseram. Australia’s industry-funded pesticide regulator, the APVMA, noted in the public release summary at the time (page 3) that’there are no approvals for this active constituent, or any product registrations anywhere in the world.’

Isocycloseram is a highly persistent insecticide that the OECD classifies as a PFAS, or ‘forever chemical’.

According to the Center for Biological Diversity, isocycloseram degrades over decades into the smaller forever chemical TFA (trifluoroacetic acid). In June 2026, the European Chemicals Agency’s scientific committee concluded that TFA should be classified as toxic to reproduction (Category 1B) – meaning it ‘may damage the unborn child’ and is ‘suspected of damaging fertility.’ TFA is one of the most widespread and persistent PFAS in the environment, building up in rain, soil, drinking water and food, and is very hard to remove once there. This overview from the Center for Biological Diversity sets out the concerns.

Pesticide regulators have also found that isocycloseram reduced testicle size, lowered sperm counts and harmed the liver in animal studies sponsored by the manufacturer. The APVMA, identified skeletal malformations in fetal rats. There are also concerns about cancer risk.

The Australian Government is currently proposing (see page 50) to increase the isocycloseram maximum residue limit (MRL) on berries by 70 to 500-fold. 

We are deeply concerned about allowing more of a forever chemical onto Australian berries. Here’s why:

• Blueberries, strawberries and raspberries are among the most popular fruits given to toddlers and young children, who eat more food relative to their body weight than adults.
• Berries are marketed as a health food. People eat more of them precisely because they’re told berries are good for them – and higher consumption means higher exposure to any residue allowed on them.

As many of you already know – or learned through the paraquat decision – writing submissions only works when a Government regulator is willing to listen.

The Albanese Government’s pesticide regulator is not an impartial actor, but puts industry profits ahead of our national interest. So a submission is a start, but it isn’t enough.