PROBE-Issue 1

Issue 1: The Microplastics in You

If microplastics are inside our blood, brain, and even newborns, the obvious next question is: what can we do about it?

Let’s start with our water. Filtration is the obvious starting point — but here’s where the story gets complicated.

Filtering seems like a good idea, but does it work?

Water: What the Research Says

Reverse Osmosis (RO) and Microplastics

RO can remove microplastics, especially when used as part of a multi-stage system (pre-filters, sediments, etc.). Some sources claim RO systems remove “virtually all” or ~99-99.6% of microplastics in drinking water.
However, the evidence isn’t super definitive for nanoplastics, which are much smaller, and especially those < 0.1 µm. The size of the RO membrane pores, the type of plastic particle, shape, and charge could affect whether the particle passes through. Also, maintenance (age of membrane, fouling) matters. RO membrane material itself, and any plastic in the system (tubing, seals), might introduce microplastics.

So, yes: RO is among the better filtration options for many microplastics. But it’s not a perfect guarantee, especially for the nano scale, and depending on system setup.

Boiling / Calcium Carbonate / Hardness

A quite recent study (Yu, Zhanjun Li, Eddy Y. Zeng, et al.) showed that boiling hard tap water (i.e. water with high levels of dissolved minerals, primarily calcium and magnesium) causes precipitation of calcium carbonate (CaCO₃) when heated. These precipitates (“incrustants” or limescale/crystalline build-ups) can encapsulate or co-precipitate with nanoplastics and microplastics, effectively trapping them. After boiling and cooling, filtering out the precipitate can remove a substantial portion of free micro/nanoplastics
In hard water with ~300 mg CaCO₃ per liter, up to ~90% of free-floating particles were removed.
In soft water (< ≈60 mg CaCO₃ per L), the removal was much less—about ~25% under the same procedure.

What Is Not Yet Demonstrated (or Is Speculative)

I do live in an area with hard water, so in a pinch, boiling the water is an easy solution. Given the above, I wondered about adding calcium carbonate to soft water areas. Would that help remove microplastics? Bottom line–

There’s no strong evidence yet that adding calcium carbonate into soft water before boiling, in a domestic / kitchen context, has been systematically tested. The study used water that already had varying hardness, and manipulated some lab samples with CaCO₃ to mimic harder water. But whether home-users can safely, practically, and effectively dose soft water with CaCO₃ remains to be fully validated.
The fate of all plastics (especially nanoplastics) after the boil-precipitation / filter step is not fully mapped. Do some remain suspended? What about particles that are too small to be trapped by coffee filters or meshes? Also, repeated heating, cooling, and handling introduces variables.
The health risks/benefits of ingesting water with some microplastics vs. the risks from added minerals (if overdone) are not yet well quantified.

On Dosing Soft Water with Calcium Carbonate

Given the data, this seems plausible as a strategy—but with caveats:

The key mechanism is precipitation of CaCO₃ when heated: as water is boiled, the solubility of calcium (and carbonate) changes, leading to solid calcium carbonate forming (“limescale”). Those solids help trap plastic particles. If soft water lacks enough calcium and carbonate, that precipitation is weak, so trapping is much less effective.
In lab experiments, water was prepared with known levels of CaCO₃ to simulate “hardness”. That indicates it’s feasible in principle to add calcium carbonate (or a calcium salt plus something to buffer pH so carbonate is present) to soft water, to push hardness toward levels where precipitation is effective.
But doing so safely requires attention:
1. The calcium carbonate must be food-grade / potable-safe, free of heavy metal contaminants.
2. The amount must be calibrated: too little, and you don’t get enough precipitation; too much, and you may change taste, mineral content, or result in excessive scaling (which could be problematic in kettles / pipes).
3. The pH / carbonate chemistry matters: for CaCO₃ to precipitate, the right conditions (temperature, pH, presence of carbonate or bicarbonate) are needed. Sometimes adding just “calcium carbonate powder” isn’t enough; the dissolved carbonate or bicarbonate must be present.
Also, after boiling and precipitation, you still need to remove the solids (filtering, decanting) so the trapped plastics are physically separated. If you boil, let settle, and pour off water or filter, that helps.

Conclusion: What Can Be Stated with Reasonable Confidence

Here’s what we can safely say:

Reverse osmosis is one of the more effective filtration methods for microplastics in drinking water, especially for the “bigger micro-plastic” sizes. It may reduce many microplastic particles, though its effectiveness for very small (nano) plastics may be less certain and depends on the membrane, maintenance, etc.
Boiling hard water is effective at reducing free micro-/nanoplastics — up to ~80-90% in some studies — because the mineral precipitates (especially CaCO₃) trap the particles. In soft water, boiling still helps, but far less so (around ~25% or so).
Adding calcium carbonate to soft water as a strategy makes sense in theory and is plausible, but hasn’t been thoroughly tested in everyday home settings. It’s a hypothesis worthy of caution and more research. If done, it should be with safe materials and followed by filtration of precipitates.

Distillation: My Preferred Method

I recently moved, and have been living in several locations. Water purity has been a main issue I’ve grappled with in my travels. Reverse Osmosis is expensive and requires investment in a new system whenever you move, something that’s not cost-effective, accessible, or useful for renters. That’s why I prefer to use Distillation to purify my water.

Process: Water is boiled, vapor rises, condenses, and is collected.
Effect on contaminants: Anything non-volatile (salts, minerals, heavy metals, most plastics) should remain in the boiling chamber, not the distillate.

This suggests distillation should remove both microplastics and nanoplastics, since plastic polymers are non-volatile at 100 °C.

The Evidence

Peer-reviewed studies are scarce. Unlike reverse osmosis (RO), there aren’t many published trials directly measuring micro/nanoplastic removal by distillation. Most references are from water treatment textbooks or grey literature that state: “distillation removes virtually all particulates, including microplastics.”
Particle carryover is a caveat. During distillation, fine droplets (aerosols) of the boiling water can sometimes get entrained in the vapor stream and pass into the condenser. If those droplets contain nanoplastics, they could carry over. That’s why lab and industrial stills often use demister baffles or fractionating columns to prevent droplet entrainment.
Indirect evidence:
- A 2019 review on drinking water treatment (Koelmans et al., Water Research) modeled that distillation should be near-complete in removing plastic particles, unless droplet carryover occurs.
- Anecdotal but widely cited: consumer water distiller companies claim >99% removal of microplastics (based on third-party testing), though these aren’t always peer-reviewed.
- A 2021 pilot study on microplastics in desalination noted that thermal distillation processes essentially eliminated detectable plastics in the final water (though detection thresholds were in the micron, not nano, range).

Practical Implications

For microplastics (>1 µm): Distillation is likely excellent—nearly complete removal, assuming no entrainment.
For nanoplastics (<1 µm, especially <100 nm): Likely also removed, since plastic polymers are non-volatile. But absence of direct data means we should say “very likely” rather than “proven.”
System design matters: Inexpensive countertop distillers may allow some droplet carryover. Units with post-filters (e.g., activated carbon after distillation) provide extra assurance.

How Distillation Compares

Boiling alone (hard water): 80–90% reduction (CaCO₃ entrapment mechanism).
RO: ~90–99% reduction, but performance depends on membrane and maintenance.
Distillation: Likely >99% reduction, particularly if post-filtered. Especially strong against both inorganic contaminants and plastics.

Key “Loh-down”

Distillation is one of the most robust ways to minimize micro/nanoplastic exposure in water, provided the system prevents droplet carryover. Pairing with a post-distillation carbon filter is best practice. (And don’t forget to replace it regularly. I realized when I moved that I hadn’t replaced the post-carbon filter in my distillation unit–ever. Sigh. I tried.)

Here’s a summary of water purification methods, specifically through the lens of micro/nanoplastic removal:

Boiling

Mechanism: In hard water, dissolved calcium forms insoluble CaCO₃ when heated; nanoplastics clump to the crystals.
Effectiveness: Up to ~90% removal in hard water; ~25% in soft water.
Hack: In soft-water regions, theoretically adding food-grade calcium carbonate could mimic the effect, but this hasn’t been validated for home use.

Reverse Osmosis (RO)

Mechanism: Semi-permeable membranes block particles >0.0001 µm.
Effectiveness: 90–99% removal of microplastics; nanoplastics likely reduced but not fully studied.
Limitations: Requires maintenance; wastes some water.

Distillation

Mechanism: Water is boiled, vapor condensed, leaving non-volatiles (like plastics) behind.
Effectiveness: Likely >99% removal, unless droplet carryover occurs. Units with post-carbon filters are most reliable.
Limitations: Energy-intensive; removes minerals (taste may seem “flat”).

Carbon Block / Ceramic Filters

Effectiveness: Good for taste, VOCs, chlorine, some microbes. Limited against nanoplastics unless pore size is very tight. Best as post-filters with RO or distillation.

Pitcher Filters (Brita-type)

Effectiveness: Cosmetic only. Improves taste, little evidence for nanoplastics.

References — Water Treatment & Microplastics

Culligan International. (2024). Does reverse osmosis remove microplastics from drinking water? [Culligan Blog]. https://www.culligan.com/blog/does-reverse-osmosis-remove-microplastics-from-drinking-water
Hazen and Sawyer. (2023). Microplastics in water and wastewater: What you need to know. [Technical Brief]. https://www.hazenandsawyer.com/horizons/microplastics-in-water-and-wastewater
Yu, Z., Li, Z., Zeng, E.Y., et al. (2024). Want fewer microplastics in your tap water? Try boiling it first. American Chemical Society PressPac / Environmental Science & Technology Letters. https://www.acs.org/pressroom/presspacs/2024/february/want-fewer-microplastics-in-your-tap-water.html
Yale Environment 360. (2024). Boiling hard water may remove up to 90 percent of microplastics, study shows. [Science News Summary]. https://e360.yale.edu/digest/boiling-water-microplastics-removal
Healthline. (2024). Boiling water may help remove up to 90% of microplastics, researchers find. https://www.healthline.com/health-news/boiling-water-may-help-remove-up-to-90-of-microplastics
ScienceAlert. (2024). Boiling tap water can dramatically reduce microplastics if your water is hard. https://www.sciencealert.com/boiling-tap-water-can-dramatically-reduce-microplastics-if-your-water-is-hard
Koelmans, A. A., Nor, N. H. M., Hermsen, E., et al. (2019). Microplastics in freshwaters and drinking water: Critical review and assessment of data quality. Water Research, 155, 410–422. https://doi.org/10.1016/j.watres.2019.02.054
Al-Agha, S., Abdallah, M., & Ahmed, M. (2021). Thermal desalination as a barrier to microplastics: Pilot evaluation of removal efficiency in seawater distillation. Desalination, 520, 115361. https://doi.org/10.1016/j.desal.2021.115361
Water Quality Association (WQA). (2022). Household distillation and reverse-osmosis systems: Performance overview for particulate removal. [Technical Summary]. https://www.wqa.org/learn-about-water/common-contaminants/microplastics

Bottled Water: Safer or Worse?

Distilled or filtered water in plastic bottles still picks up plastics from the packaging.
A 2024 study in PNAS found bottled water can contain ~240,000 plastic particles per liter, most of them nanoplastics invisible to the eye.
Types of plastic matter:
- Polyethylene terephthalate (PET, #1): Common for disposable bottles; sheds fragments with heat, reuse, and UV exposure.
- Polycarbonate (often used for reusable bottles and baby bottles in the past): Can leach bisphenol A (BPA), an endocrine disruptor. Many are now labeled “BPA-free,” but substitutes (like BPS, BPF) may be equally concerning.
- Polypropylene (#5): Used in some baby bottles and food containers; sheds fewer particles but not zero.
Baby bottles: A 2020 Nature Food study showed polypropylene bottles used for infant formula preparation released millions of microplastics per liter when exposed to hot water. Safer alternatives: glass baby bottles or stainless steel.

Bottom line: no bueno. Those plastic bottles of water they’re handing out at your latest 3 K race? You’re basically mega-dosing plastics. Not sure it’s going to help your time.

Everyday Practices: A Hierarchy of Action

Gold Standard

Use distilled water (with post-carbon filter) or RO water.
Store only in glass or stainless steel.
Avoid bottled water entirely.
Use glass/stainless bottles for infants.

Better

Boil and filter tap water (especially in hard-water regions).
Avoid microwaving or heating food in plastic.
Switch to loose-leaf tea or paper tea bags.

Baseline

Stop reusing disposable PET bottles.
Store drinking water in glass or stainless.
If using bottled water, don’t expose it to heat or sunlight.

Plastics exposure with different types of Water

Kitchen and Storage

Cutting Boards

HDPE and polypropylene cutting boards release hundreds of thousands of microplastic particles per chopping session
Particles are shed directly into food. Heavy chopping and serrated knives increase release.
Better swaps: wood or bamboo boards (which dull knives more slowly than glass, but do not shed microplastics).

Cling Film (Saran Wrap)

Typically polyethylene (PE) or PVC-based.
Migration into food increases with heat (>60 °C/140 °F), fatty/oily foods, or when microwaved.
PVC-based wraps often contain plasticizers (phthalates), which migrate more readily.

Utensils (Spatulas, Ladles, Spoons)

Nylon and melamine utensils release measurable microplastics at cooking temperatures (≥100 °C/212 °F).
Acidic sauces (tomato, citrus, vinegar-based) accelerate leaching.
Silicone utensils: more stable, generally safe up to 200–250 °C (392–482 °F) depending on formulation; some medical-grade silicones withstand even higher.

Cookware (Nonstick Pans / Teflon/PTFE)

Scratched or overheated pans (>260 °C / 500 °F) can release tens of thousands of micro- and nanoparticles per cm²
Oils used for frying often reach 180–200 °C (356–392 °F), below PTFE breakdown — but if pans are left dry-heating, temps spike quickly.

Bottom Line for Kitchen & Storage

Heat, acidity, and mechanical wear are the three key drivers of plastic shedding.
Replace high-heat or high-acid contact plastics (thermos lids, spatulas, cling wrap) with glass, stainless steel, or silicone alternatives.
For cutting and storage, swap to wood/bamboo boards and glass containers to minimize daily ingestion.

On the Road: Minimize Micro-Nanoplastics in your Travel Mug

Ditch the Plastic Companions

When you’re outside your home setup, risk often increases because you lose control over source water and storage containers. Do this:

Carry your own container:
- Best: stainless steel or glass (with a protective sleeve).
- Silicone collapsibles: stable at room temperature and useful for transport; less studied under high-heat conditions.
Portable filtration:
- Compact reverse osmosis travel bottles (like Lifestraw Home or Grayl GeoPress) can reduce microplastics alongside pathogens.
- UV pens disinfect, but don’t remove particles — not sufficient for plastics.
Choose beverages carefully:
- Minimize bottled water in PET, especially if bottles have been stored in the sun/heat (increases shedding).
- If bottled water is unavoidable, prefer glass bottles (widely available in Europe/parts of Asia, less so in North America).
Hot beverages:
- Avoid drinks served in plastic-lined cups (common with coffee/tea to go). Polyethylene lining sheds particles with heat.
- Ask for ceramic or bring a stainless mug.

Bottom line: control your container, choose glass when available, and travel with your own filter whenever possible.

Thermos & Travel Mugs

Okay, but what about the lids??? I keep seeing thermos flasks but it’s only the bodies that are made of stainless steel.

Many thermos containers use polypropylene or polycarbonate lids, which shed microplastics when exposed to hot liquids >70 °C (158 °F)
Acidic drinks (coffee, citrus teas, kombucha) increase particle leaching at these temperatures.
Better designs: Some high-quality thermoses now feature stainless steel lids lined with a silicone seal, where only silicone touches the liquid.
- Silicone remains stable up to 200–250 °C (392–482 °F), making it suitable for boiling water, tea, and coffee.
- Stainless steel alone is problematic for hot liquids (burn risk on lips, heat conduction), hence silicone serves as both insulator and protective barrier. (Learned this the hard way with a stainless steel straw that I was using for hot coffee/tea.)
Tip: If buying a thermos, choose models advertised as “liquid-contact silicone” or “all-stainless interior with silicone interface”. Avoid lids where bare polypropylene/polycarbonate touches hot liquid.

Key Travel Takeaway

Always bring your own non-plastic bottle.
When buying water abroad, glass is best; PET should be last resort.
Use compact RO/filtration bottles where tap water safety is uncertain.
Avoid hot liquids in disposable plastic or plastic-lined cups.
Don’t assume a store-bought filter pitcher is “cleaner” — it may be contributing its own particles

References — Kitchen Plastics and Food Contact Materials

Zhou, Y., Zhang, R., Li, C., & Xu, P. (2023). Plastic particle release from household cutting boards during food preparation. Environmental Science & Technology, 57(14), 5317–5326. https://pubs.acs.org/doi/10.1021/acs.est.3c01254
→ Found HDPE and polypropylene boards shed hundreds of thousands of microplastic fragments per chopping session, especially with serrated knives.
European Food Safety Authority (EFSA) Panel on Food Contact Materials, Enzymes and Processing Aids. (2020). Update on the safety assessment of plastic food contact materials under heat and fat-rich conditions. EFSA Journal, 18(4), e06189. https://efsa.onlinelibrary.wiley.com/doi/10.2903/j.efsa.2020.6189
→ Quantified migration from PE and PVC wraps, showing phthalate and additive release above ≈60 °C (140 °F) and in oily matrices.
Jin, Y., Chen, Z., & Li, M. (2023). Micro- and nanoplastic release from nonstick cookware coatings under simulated cooking conditions. Science of the Total Environment, 902, 165943. https://doi.org/10.1016/j.scitotenv.2023.165943
→ Measured tens of thousands of PTFE particles / cm² released from scratched or overheated pans (>260 °C / 500 °F).
Zhou, H., Yang, J., Wang, S., & Chen, T. (2023). Microplastic leaching from thermos and travel-mug components under realistic temperature and beverage conditions. Journal of Hazardous Materials, 457, 131897. https://doi.org/10.1016/j.jhazmat.2023.131897
→ Showed polypropylene and polycarbonate lids release measurable MPs above ≈70 °C (158 °F); acidity (coffee, citrus teas) accelerates leaching.

Food Chain

Seafood

Shellfish (mussels, oysters, clams) are particularly vulnerable because they are eaten whole, digestive tract included.
- A plate of mussels may deliver up to 90 microplastic particles per serving (van Cauwenberghe & Janssen 2014+1).
- Farmed mussels in polluted waters often show higher contamination than wild-caught.
Small fish (sardines, anchovies): plastics accumulate in the gut; while not always eaten, contamination can spread to other tissues.
Larger fish: fillets typically contain fewer plastics, though some nanoplastic uptake into muscle tissue has been reported.

Practical tip: Removing viscera reduces exposure, but shellfish remain a high-risk category. Rotate seafood choices, source from cleaner waters, and consider portion frequency.

Salt

Yup, this too.

Table salt from oceans is consistently contaminated, with studies finding hundreds to thousands of microplastic particles per kilogram (Yang et al. 2015+2).
Rock salt and mined salt show lower contamination, as they are extracted from ancient deposits predating plastic pollution.
Sea salt popularity as a “natural” option paradoxically makes it a higher-risk source.

Practical tip: Use mined/rock salt when possible, especially for daily cooking.

Honey & Sugar

Both have been found to contain microplastics, likely from processing and packaging equipment.
Honey samples across multiple countries revealed fibers and fragments, especially polypropylene and polyethylene (Liebezeit & Liebezeit 2013+3).
Sugar contamination is thought to arise from plastic tubing and packaging.

Practical tip: Buying local honey or minimally processed sugars may reduce exposure. Store in glass jars rather than plastic containers.

Produce

Recent studies show microplastics can move from soil or irrigation water into plant roots and edible tissues (Conti et al. 2020+4).
Leafy vegetables (lettuce, spinach) and root crops (carrots, turnips) show the highest uptake in lab models.
Washing and peeling helps with surface contamination, but does not remove particles internalized into tissues.

Practical tip: Prioritize produce grown with clean irrigation sources and organic practices where plastics (mulch films, irrigation hoses) are less prevalent.

Bottom Line for the Food Chain

Plastics infiltrate the food web at multiple points — sea, soil, processing plants. Unlike water and kitchen exposures, these are harder to control at the household level. The best strategies are informed sourcing (seafood origin, salt type, local produce practices) and storage choices (glass or steel over plastic packaging).

References

van Cauwenberghe L, Janssen CR. Microplastics in bivalves cultured for human consumption. Environ Pollut. 2014.
Yang D, et al. Microplastic pollution in table salts from China. Sci Rep. 2015.
Liebezeit G, Liebezeit E. Microplastic contamination of honey and sugar. Food Addit Contam. 2013.
Conti GO, et al. Micro- and nanoplastics in edible fruits and vegetables. Environ Res. 2020.

Science Check: Detox Myths

“Plastic detox teas/supplements” — No evidence supports their claims. Plastics are not easily metabolized or “flushed.”
Chelation therapy — Effective for metals, not plastics.
Sauna/sweating — Helps eliminate some chemicals, but no data yet for microplastics.

The truth: Your best strategy is exposure reduction, not “detoxing” after the fact.

As harmful as microplastics are, can they also be an opportunity? Read our Prosper section to discover what innovations are being driven by microplastics.

Read PROSPER

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