Microplastics in Coffee Cups: Uncovering the Hidden Dangers Lurking in Your Morning Brew

Coffee is drunk from disposable paper cups by millions of people every single day, and virtually no one questions whether it’s healthy.

It’s just paper, right… or is there more to it?

It appears there is.

Studies have found the materials in disposable coffee cups can be toxic to living organisms.

For example, this study¹ showed that the chemicals from these cups can slow growth and development of aquatic midge larvae, frequently used in toxicity tests.

In this article, we’ll delve into the issue of microplastics in coffee cups, explore how these tiny particles end up in your morning brew, and discuss the potential health hazards they may pose.

The aim is not to be alarmist, but simply to highlight a phenomenon that many are unaware of.

Table of Contents

How Toxic Substances End Up in Your Coffee and Their Potential Health Impact

Your morning cup of joe might be piping hot, but what you may not realize is that it could also be piping with microplastics and other toxic elements.

But how do these substances find their way into your coffee?

A recent study² has shed some light on this issue.

As it turns out, the culprit is the plastic polyethylene film that lines the interior of disposable coffee cups to prevent their contents from seeping into the paper. This thin lining starts to break down when it comes into contact with hot water (85-90 °C), and this process releases toxic chemicals out of the materials that make up the lining. The researchers found that, on average, 25,000 microplastic particles are released into a 100 ml cup of coffee over just 15 minutes.

The researchers also found traces of heavy metals, including lead (Pb), chromium (Cr), and cadmium (Cd), as well as ions like fluoride, chloride, sulfate, and nitrate in the liquid and the plastic lining of these cups.

In another study³ researchers found trace amounts of certain metals like vanadium, chromium, copper, cobalt, and arsenic, and also some ions like nitrate, nitrite, chloride, bromate, fluoride, and sulfate. The amounts were below what’s considered safe in drinking water by the World Health Organization (WHO). However, according to the study, the concentrations of vanadium and fluoride could be risky if you drink regularly from these cups over a long period of time.

Ingestion of microplastics and heavy metals is recognized as a potential threat to human health. Here is what we know so far regarding the potential health impact of these substances:

Microplastics
The full extent of microplastics’ impact on human health is still a subject of ongoing research, but there are several deleterious health effects⁴ have been associated with, including disruption of the immune system, alteration of metabolism, reproductive toxicity, and even carcinogenicity.

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Heavy metals
Heavy metals have long been known to damage vital organs, even at low levels of exposure. For example, lead exposure is associated with⁵with impaired brain development in children. Cadmium is toxic to the kidney, liver, and bones, in addition to being classified as a Group 1 carcinogen by the International Agency for Research on Cancer.

While it’s true that exposure to these substances can be toxic, we cannot shield ourselves from them entirely. Microplastics and heavy metals are pervasive in our environment, and they enter our bodies through various routes. We inhale them in the air, ingest them with food, and even get exposed to them through physical contact with surfaces. So, it only makes sense to ask:

Given our daily exposure to these substances, does the additional intake from drinking from paper cups significantly increase our health risk?

Addressing this question conclusively is challenging. The answer likely hinges on various factors, including one’s personal exposure and sensitivity to these substances. The health implications of drinking from paper cups are still under scientific scrutiny.

It’s also not as straightforward as merely tallying the number of microplastics emitted and deducing that more particles equals a higher risk.

A 2022 study by Pletz⁶ indicates that the size of microplastic particles matters. Smaller particles, for instance, pose a potentially higher threat as they can infiltrate the bloodstream and organs more readily than their larger counterparts.

The shape of the microplastics is also crucial. A 2021 study showed⁷showed that sharp or irregularly shaped microplastics tend to have a more pronounced adverse effect on the immune system.

In essence, microplastics are diverse in nature, and further research is essential to grasp their varying impacts.

As a safety measure, it might be prudent to advise against children consuming hot drinks from disposable paper cups. Their bodies are still maturing, making their organs and immune systems potentially less resilient than adults. Consequently, they might be more vulnerable to the potential hazards of the substances in these cups.

For instance, lead — a neurotoxin found in the plastic lining of some cups — can be particularly detrimental to children’s development, leading to reduced IQ, issues with perception and concentration, and hyperactivity.

Unanswered Questions

So, we’ve established that:

There are 1,000’s of microplastic particles emitted from the polyethylene film when exposed to hot liquid.

What is unclear still are:

How much extra exposure per day are we talking about in terms of microplastics?
For example, are we talking about a 1%, 10% or 100% increase in daily exposure? We need an idea of scale, given that we are already exposed to these compounds each day.
We need to know what kind of effects this increase in exposure may have over the long term.

Exploring Potential Solutions

Considering the potential health risks, it’s worth reevaluating the materials used in coffee cups at the industry level. In doing so, we must address not only the leaching problem but also the sustainability and costs. With this in mind, here are some potential solutions:

Glass
A potential contender is glass, which initially may seem like a great option. It is chemically inert, meaning it won’t leach any unwanted substances into your drink. It also has low thermal conductivity, which slows down the heat’s escape from your coffee, keeping it toasty for longer. However, the production of glass has a larger environmental footprint compared to plastic. Why? Because it’s created from natural raw materials like sand, which requires mining and melting at extremely high temperatures. It’s also more fragile and prone to damage than the next option.

Stainless Steel
Stainless steel is the superhero of reusable water bottles. It is durable, environmentally safe, and it doesn’t leach toxic chemicals. However, it doesn’t do a very good job of insulating heat. That means your coffee might cool down faster in a stainless steel cup than glass or paper.

Yet, it’s worth noting that thicker, double-walled stainless steel cups are better at keeping your beverage warm for longer. This begs the question: Why can’t we then replace paper cups with double-walled stainless steel cups?

One reason is that stainless steel cups would be much heavier and therefore less convenient to carry on the go. Secondly, stainless steel, being a durable and long-lasting material, is more expensive than the paper used for disposable cups.

As we continue our search for safer and more sustainable solutions, it’s becoming clear that finding a replacement for paper coffee cups will likely require more innovative and unconventional approaches.

For example, some companies are producing edible cups made from waffles! (For the record, we just mention this for fun, it’s not a healthy solution!)

Closing Words

Hopefully the above has given an indication of the possible issues related to disposable coffee cups – including the questions still yet to be answered.

Whilst I’m not personally worrying about drinking disposable cups occasionally, it’s still good to be able to make more informed health choices.

If you’ve any questions or comments, please leave them below in the comment section!