Te Henga is not just “a place where willow trees grow.”
It’s a wetland system, and wetlands are the kind of environment where decisions around agrichemicals carry higher stakes—because water, saturated soils, and hydrological connections make both exposure and persistence harder to dismiss. Over the past week, concerns about glyphosate-based herbicide spraying in Te Henga (West Auckland) have resurfaced in a way that deserves public attention, not quiet continuation.
This isn’t written as a personal attack on anyone doing conservation work. It’s written because when chemicals with aquatic hazard classifications are used in or near wetland environments, the burden of transparency is high. People don’t need slogans. They need clear documentation: what was used, how it was applied, what safeguards were in place, and what monitoring was done before and after.
What has been reported about glyphosate spraying in Te Henga
A recent media release from the Weed Management Advisory (WMA), dated 3 March 2026, states that an application was filed with the Environment Court in Auckland for an interim enforcement order seeking to immediately stop aerial spraying of agrichemicals over the waterways and wetlands of Te Henga. The WMA has also stated that, despite this, the spraying went ahead.
The WMA describes the operation as a multi-year campaign and notes community concern about the lack of due process and consultation, particularly given the ecological sensitivity of the area and the presence of endangered wildlife.
Which chemicals were reportedly used in the Te Henga spraying
A technical review prepared by Charles Hyland (Soil & Health Association of New Zealand), dated 26 September 2025, states that two products were reportedly used at Te Henga:
- Polaris 450 (a 450 g/L glyphosate isopropylamine salt formulation)
- Aquakynde (an added surfactant adjuvant)
The key point here is not the brand name. It’s the hazard profile and what it implies for use around water.
Polaris 450: hazard classifications and waterway warnings
The technical review notes that Polaris 450’s EPA approval classification includes hazard statements indicating it is harmful if inhaled, causes serious eye irritation, and is toxic to aquatic life with long-lasting effects. The review also notes that the Safety Data Sheet (SDS) for Polaris 450 instructs users not to allow the product to enter waterways.
In a wetland environment, that instruction matters. Wetlands are not dry paddocks. They are water-connected ecosystems.
Aquakynde surfactants and aquatic toxicity
The same technical review notes Aquakynde’s hazard classifications, including serious eye damage and aquatic harm classifications. It also discusses that surfactant chemistry of the type reportedly present is known to be harmful to aquatic organisms at low concentrations.
Why herbicide spraying in wetlands increases environmental risk
Even when spraying is conducted with care, wetlands present exposure pathways that are difficult to fully control. The Hyland review describes wetlands as intrinsically high-exposure settings because spray drift, wash-off, and hydrological connectivity can move herbicide–surfactant mixtures into standing water and saturated sediments, where they may persist. It also notes that glyphosate can bind to sediments and break down into AMPA (aminomethylphosphonic acid), which can persist, extending the exposure window.
The review highlights a key scientific point that is often missing from public debate: in many studies, the aquatic toxicity of glyphosate-based products is strongly influenced by the surfactant system and co-formulants, not glyphosate alone. That matters when additional surfactants are used.
What monitoring and safeguards should be disclosed to the public
If spraying is occurring in or adjacent to a wetland ecosystem, the public should not have to rely on reassurances. The baseline expectation should be disclosure—especially when legal action is underway and community trust has already been strained.
At minimum, we believe the following should be publicly available in plain language:
1) Monitoring and environmental testing
Monitoring and testing are not the same thing. Monitoring can include observational checks; testing involves sampling and lab analysis. The Hyland review recommends baseline and post-event sampling for glyphosate and AMPA in water and sediment, along with basic biota checks such as amphibian larval presence/absence transects.
If monitoring and testing are being done, the public deserves to know:
- who commissioned it
- who carried it out
- where samples were taken
- what methods were used
- what was found
- and whether results will be published
2) Spray drift risk and local wind conditions
Spray drift is not theoretical. Coastal and wetland environments can experience regular wind shifts and airflows that locals know intimately. It is reasonable for residents to ask what drift reduction methods were used, what weather triggers were set, what buffers were mapped, and what records exist for wind and application conditions on the day(s) of spraying.
3) Impacts on endangered species and non-target wildlife
If an operation is occurring in habitat associated with endangered species, the public should be able to see what surveys were conducted, what protection measures were put in place, and what post-operation checks occurred to assess unintended effects on non-target species and ecosystems. If the impacts of prior spraying seasons were assessed, that information should be shared.
4) Health considerations for people with chemical sensitivity
Some people live with chemical sensitivity or respiratory vulnerability. In a public place, this cannot be dismissed as fringe. If agrichemicals are being applied in a way that could affect public access or nearby residents, communication and risk management should reflect that reality.
5) Community notification and “social licence”
Whether or not formal consultation was legally required, community awareness is still a basic expectation. If locals feel they had no meaningful notice—especially outside private mailing lists—then something has already failed. Transparency isn’t optional in public spaces; it’s part of guardianship.
Why a precautionary pause is the responsible course of action
This is not an emergency situation. Taking the time to ensure environmental safeguards and community concerns are properly addressed should be the responsible course of action.
The Hyland technical review is clear on the bottom line: spraying in, over, or immediately adjacent to standing water in a wetland creates a high-risk exposure pathway that is difficult to keep compliant and is readily avoidable. The review recommends a precautionary pause, an independent compliance audit, switching to contact-limited methods, and basic monitoring.
What No More Glyphosate NZ is calling for
No More Glyphosate NZ is calling for:
- a precautionary pause on herbicide spraying in and immediately adjacent to standing water in Te Henga wetlands
- an independent compliance review, including publicly released findings
- baseline and post-event water and sediment testing for glyphosate and AMPA, with results published
- clear disclosure of spray plans, mapped buffers, drift controls, operator competence, and spray records
- transparent reporting on wildlife protection measures and post-operation checks
- improved community notification, including public channels locals actually use
These are not radical demands. They are what accountability looks like when decisions have ecological and public consequences.
Where the Te Henga spraying debate now stands
People can support wetland restoration and still question whether aerial spraying of herbicide mixtures in a wetland is wise, necessary, and adequately governed. Those positions are not mutually exclusive.
When the public is told “trust us,” but is not shown monitoring plans, sampling data, drift controls, and decision records, trust doesn’t grow—it erodes. The fastest way to rebuild it is simple: publish the evidence, disclose the process, and pause long enough for independent scrutiny to do its job.
Resources & references
Weed Management Advisory (WMA). Drone Spraying of Glyphosate Over Endangered Species Habitat at Te Henga Goes Ahead Despite Environment Court Appeal. Media release, 3 March 2026.
Polaris 450 — Safety Data Sheet and EPA hazard classifications
Aquakynde — Safety Data Sheet, hazard classifications and surfactant notes
Image Source & Attribution
We’re grateful to the photographers and contributors whose work enhances our content. The feature image on this page was supplied by Bruce White.
