The Recycled Bottle Is the More Contaminated One

The short answer

If you have been choosing the bottle that says “made from 100% recycled plastic” on the assumption that it is the cleaner option to drink from, the evidence does not support that assumption. It supports the opposite, weakly, and mostly for two specific chemicals.

The logic is not complicated once you see it. Virgin PET starts as polymer and additives and nothing else. Recycled PET starts as bottles that held something, sat somewhere, were collected with other things, were sorted imperfectly, and were then melted again. Every one of those steps is a chance to pick something up, and none of them is a chance to put something back to new.

What the research actually is

The central source here is Gerassimidou and colleagues at Brunel University London, published in the Journal of Hazardous Materials in March 2022. It is worth being precise about what kind of study it is, because much of the coverage is not.

It is a systematic evidence map, not a laboratory test. The team did not buy bottles and measure them. They gathered what the published literature already reported about food-contact chemicals across the entire PET bottle value chain and organised it — which makes it good for seeing the shape of the field, and unsuitable for quoting as “a study that tested bottles and found X”.

What they mapped: 193 food-contact chemicals investigated across the lifecycle, of which 150 have been detected migrating from PET bottles into food simulants or food samples. Most of the research attention has gone to antimony, acetaldehyde and a set of well-known endocrine-disrupting compounds.

And on recycling, the sentence that matters: “the higher migration of Sb and Bishphenol A has been reported in recycled (rPET) compared to virgin PET” — which they attribute to “multiple contamination sources and the variability in the collection, sorting, and decontamination efficiency”.

One widely repeated line does not come from this paper: the claim that 18 chemicals were found exceeding health regulations. That appears in news coverage; we could not verify it against the primary source, so it is deliberately absent from this page.

Why antimony keeps coming up

Antimony is not something that falls into recycled plastic by accident.Antimony trioxide is the catalyst used to manufacture PET in the first place, which means it is present in essentially all PET, virgin included. That is precisely why it is the most-studied chemical in this literature — it is always there, so it is the natural thing to measure, and differences between virgin and recycled material show up against it clearly.

Its behaviour is also the familiar one: migration increases with heat and storage time. Which is the same mechanism behind what happens to a bottle left in a hot car, and it stacks with everything above.

Why recycled plastic accumulates what virgin does not

There are four distinct entry points, and they are cumulative:

• The previous contents. A bottle that held a flavoured or oily product can absorb components of it into the polymer. Those do not necessarily leave during reprocessing.
• Non-food-grade material in the stream. Collection is imperfect, and PET that never held food — packaging, textiles, trays — can enter a bale destined for bottles.
• Misuse before disposal. Bottles are widely reused as containers for household chemicals, fuels and solvents before being thrown out. Sorting cannot reliably detect that.
• Another thermal cycle. Reprocessing means melting again. PET degrades with heat, and each cycle shortens chains and generates breakdown products, which is why recycled material is often blended with virgin rather than used alone.

Decontamination processes exist and work — that is the entire point of “food-grade” recycling. But the authors’ phrase is variability in decontamination efficiency. The process is real; its consistency is the open question.

The part that makes this awkward

Recycled content is not a niche claim any more. It is becoming the default on food-contact plastic, driven by genuine and reasonable pressure to cut virgin production. Brands advertise it prominently because consumers reward it — NutriBullet, for one, moved its blending cups to Tritan Renew, made with 50% certified recycled content, and says so on its own sustainability page.

That creates a genuine tension rather than a villain. The environmental case for recycled content is strong and this page does not dispute it. The food-contact case is the one that has been assumed rather than demonstrated, and those are different questions that the same three words on a label are currently answering at once.

It is also the fourth time this pattern has appeared on this site. “BPA-free” described one molecule’s absence, not safety. “Microwave safe” described a container not melting, not particles. Tritan is genuinely bisphenol-free and still abrades at the cap. Now “100% recycled” describes where the material came from. Every one of those claims is true. None of them answers the question the shopper is actually asking.

What we still do not know

• How large the difference is. The finding is directional — higher migration reported — not quantified into a reliable ratio. Anyone giving you a precise multiple is going beyond the evidence.
• Whether it matters at the doses involved. Detecting migration is not the same as demonstrating harm at real exposures, and the paper does not make that claim.
• Whether current processes have closed the gap. The map was published in 2022 and draws on earlier literature. Decontamination technology has not stood still.
• Almost everything, by the authors’ own account. They describe the safety implications of PET recycling as underexplored. That cuts both ways, and it is the honest summary of the field.

What to actually do

Nothing here justifies a panic, and none of it changes the case for recycling as waste policy. What it changes is which signals you trust when the material will be touching your food:

• Stop reading “recycled” as “cleaner to drink from”. Read it as what it is — a claim about feedstock and waste, which is a good thing that is answering a different question.
• Heat is still the biggest lever you control. Migration rises with temperature and time regardless of virgin or recycled, so not leaving bottles in cars, sun or warm cupboards does more than choosing between the two.
• For water you drink daily, the material question beats the sourcing question. Glass or stainless steel sidesteps the entire virgin-versus-recycled debate, because neither is PET.
• Do not reuse a drinks bottle for anything but drinks, and do not store chemicals in one before recycling it. That is one of the documented contamination routes, and it is the only one an individual actually controls.
• Keep recycling. The response to this finding is better decontamination standards and more research, not less collection. Treating it as an argument against kerbside recycling would be the wrong lesson entirely.

Related reading: what the recycling numbers actually mean, is BPA-free plastic safe, is Tritan a microplastic, bottled water brands ranked, and bottles left in a hot car.