We’ve blamed the sun for New Zealand’s melanoma epidemic for decades — but new global research points to a different culprit hiding in plain sight.
Public health messaging focuses (understandably) on UV exposure — and yes, our sunlight is brutal. But our melanoma rates don’t just affect surfers and outdoor workers. They affect every region, including those that aren’t sunny holiday destinations.
Which leads to a very uncomfortable possibility:
What if UV is only part of the story?
A new study from Pennsylvania, published in JCO Clinical Cancer Informatics (2025), adjusted for UV exposure.
The melanoma clusters still aligned closely with:
- More cultivated cropland
- More herbicide-treated acreage
- More agricultural chemical use overall
And notably, eight of the 15 high-melanoma counties were metropolitan.
Meaning: you didn’t have to be a farmer to be exposed.
Air drift, dust, water runoff and household contamination were all identified as possible pathways.
So now think about New Zealand.
We have:
- Extensive monocropping
- Heavy pre-harvest desiccation of wheat, barley and oats
- High glyphosate use compared to the EU
- Food crops, pasture, and horticulture all routinely sprayed
- Rural–urban blending in regions like Canterbury, Waikato, Hawke’s Bay and Bay of Plenty
We also have increasing pesticide use — especially herbicides.
And we have no national pesticide exposure monitoring, no biomonitoring, and no environmental pesticide surveillance system.
So how would we know if something similar is happening here?
Short answer: We wouldn’t.
Could Herbicides Contribute to Melanoma? What the Science Suggests
Researchers have long suggested plausible mechanisms linking herbicides — including glyphosate — to melanoma risk.
These include:
- Oxidative stress
- DNA damage
- Endocrine disruption
- Immune suppression
- Increased photosensitivity
The Pennsylvania study highlighted all of these — and pointed out that herbicides are literally designed to disrupt biological systems.
Which is… fine if you’re a weed.
Less ideal if you’re a human.
New Zealand pathology specialists have quietly raised similar concerns over the years — especially regarding DNA damage, oxidative stress, and endocrine disruption, all of which are increasingly linked to glyphosate in emerging studies.
So again, the question becomes:
Why is nobody looking at this in New Zealand?
Has New Zealand Ever Studied Melanoma and Herbicide Exposure Together?
To our knowledge: No.
There is:
- No region-level melanoma spatial analysis that accounts for agricultural spraying.
- No national data linking melanoma to herbicide use.
- No long-term environmental pesticide monitoring.
- No biomonitoring of herbicide metabolites in the population.
- No public datasets tracking herbicide drift or residue deposition.
We keep saying “UV, UV, UV” — as though sunlight is the sole variable.
But when a US research team can adjust for sunlight and still see stronger associations with herbicide use, it’s reasonable — responsible — for New Zealand to ask similar questions.
And yet… nobody is.
Could Melanoma Clusters Exist in New Zealand? Regions Worth Investigating
If a NZ equivalent of the Pennsylvania study were carried out, certain regions stand out as obvious starting points:
- Canterbury — large-scale cropping, heavy pre-harvest desiccation
- Waikato — maize, pasture renovation, drystock operations
- Hawke’s Bay — orchards, vineyards, extensive herbicide use
- Southland — grain cropping, pasture management
- Bay of Plenty — kiwifruit, avocado, high spray frequency
If melanoma cases cluster around cropping zones or high herbicide-use zones, that’s important.
If they don’t, that’s important too.
Either way, the science needs to be done.
Why Isn’t New Zealand Studying This? A Necessary but Uncomfortable Question
Let’s be honest:
- Melanoma gets framed as a “sunburn problem.”
- Agriculture gets framed as “the backbone of the economy.”
- Herbicides get framed as “safe when used as directed.”
And questioning any of those narratives is… inconvenient.
But public health isn’t about convenience.
It’s about asking uncomfortable questions when the evidence points toward them.
And the Pennsylvania study is a very loud, very clear signal that someone should be asking those same questions here in New Zealand.
Could NZ Be Experiencing the Same Pattern — Without Realising It?
Imagine overlaying:
- Regional melanoma rates
- Regional herbicide-use intensity
- Cropland density
- Drift patterns
- Water contamination
- Rural–urban fringe communities
Would we see clusters?
Would they match?
Would they surprise us?
We don’t know.
But isn’t it time we did?
Maybe What NZ Really Needs Is a Curious Researcher (or a Brave PhD Student)
Here at NoMoreGlyphosate.nz, we’re not researchers — but we’re very good at asking questions that nobody else is asking.
So let’s plant a seed.
Mock Advertisement (But Only Half Joking):
PhD Candidate Wanted
Topic: Agricultural Herbicide Exposure and Melanoma Risk in New Zealand: A Spatial, Environmental, and Public Health Analysis.
Must be:
- Curious
- Independent
- Resistant to industry pressure
- Capable of wrangling large datasets
- Motivated by public health, not politics
Will receive:
- Eternal gratitude from future generations
- Thanks from communities who deserve better information
- Likely a fair amount of pushback (badge of honour)
Apply within.
(Or talk to us — we’ll point you in the right direction.)
Because someone needs to pick this up.
And if not now, when?
What We Already Know About Glyphosate and Cancer
If melanoma risk is now being linked to herbicide exposure in emerging research, it’s worth remembering something else:
New Zealand already has major unanswered questions about glyphosate and cancer.
We know:
- Glyphosate is classified by IARC as “probably carcinogenic to humans.”
(Based on a 2015 working group of 17 experts from 11 countries.) - Thousands of people worldwide have taken Roundup manufacturers to court for non-Hodgkin lymphoma — and billions have been paid out.
- Oxidative stress, endocrine disruption, and DNA damage (all highlighted in the Pennsylvania melanoma study) are also the same biological pathways implicated in glyphosate’s cancer risk.
- Our own testing at NoMoreGlyphosate.nz shows glyphosate in everyday NZ foods, including cereals, oats, bread, and honey — meaning exposure is not theoretical.
- Several New Zealand toxicologists and environmental health researchers have raised concerns about the lack of long-term, low-dose pesticide research — including glyphosate — and the absence of national biomonitoring needed to understand cumulative exposure
So the melanoma findings don’t exist in a vacuum.
They fit into a bigger, uncomfortable pattern:
glyphosate’s health impacts may be far broader than cancer agencies or regulators have admitted.
Is It Time for NZ to Investigate Herbicides and Melanoma?
The Pennsylvania study doesn’t prove that herbicides cause melanoma.
But it strongly suggests they may contribute to melanoma risk — and that cropping intensity and agricultural chemical use matter more than previously recognised.
New Zealand should not wait another decade to ask the same questions.
We could be missing something big.
Or we could confirm there’s nothing to see.
Either outcome strengthens public health.
And that’s the whole point, isn’t it?
Maybe melanoma isn’t just about sun exposure.
Maybe the chemical landscape around us deserves a closer look.
And maybe — just maybe — this is the beginning of that conversation.
Resources & References
Before anyone rushes to say “it’s just the sun,” it’s worth looking at what the research actually shows. These studies don’t claim herbicides cause melanoma — but they do raise serious, credible questions about how agricultural chemicals interact with human health.
And if the data suggests we should be paying closer attention, shouldn’t we at least look?
Below are key studies that informed this article and help frame the conversation we should be having in New Zealand.
Harvesting Risk: Agricultural Practices and Melanoma Incidence (2025)
A major population-level study from Pennsylvania showing melanoma rates were significantly higher in regions with more cultivated cropland and herbicide-treated acreage — even after adjusting for UV exposure.
https://ascopubs.org/doi/10.1200/CCI-25-00160
Pesticide Exposure and Melanoma Risk in Outdoor Workers (2010)
A case-control study identifying elevated cutaneous melanoma risk among people with occupational pesticide exposure, suggesting UV is not the only environmental factor at play.
https://pmc.ncbi.nlm.nih.gov/articles/PMC2898858/
Pesticides and Cancer: Findings from the Agricultural Health Study (2004)
A long-running US cohort of pesticide applicators and their families; while not all associations were strong, it remains a foundational dataset linking various pesticides to cancer outcomes, including skin cancers.
https://pmc.ncbi.nlm.nih.gov/articles/PMC1253709/
Pesticide Drift and Residential Exposure Risks (2024)
A spatial-risk modelling paper demonstrating how pesticide drift, dust, and proximity to cropland can significantly increase exposure for nearby residents — a key concept mirrored in the Pennsylvania findings.
https://arxiv.org/abs/2402.10990
Photosensitising and DNA-Damaging Effects of Agricultural Pesticides (Review)
A scientific review outlining biological mechanisms by which herbicides and pesticides may contribute to melanoma, including oxidative stress, endocrine disruption, immune suppression, and DNA damage.
https://www.frontiersin.org/articles/10.3389/fcacs.2024.1368086/full
Long-Term Glyphosate Exposure and Tumour Formation in Animal Models (2025)
Experimental research showing that lifelong exposure to glyphosate-based herbicides can induce both benign and malignant tumours — strengthening biological plausibility for the melanoma signal seen in population studies.
https://ehjournal.biomedcentral.com/articles/10.1186/s12940-025-01187-2
New Zealand is still operating in a scientific blind spot. We’re told glyphosate is “safe when used as directed,” but we have no national biomonitoring, no environmental surveillance, and no region-by-region chemical exposure data to compare against our melanoma statistics.
These studies aren’t here to prove a point — they’re here to show what we aren’t measuring.
If other countries can find patterns worth investigating, then surely New Zealand can at least ask the same questions.
Because when it comes to melanoma, maybe sunlight shouldn’t be the only thing under the microscope.
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