Microplastics are on everyone’s lips – in the truest sense of the word. These tiny plastic particles, which are smaller than five millimetres, have become a major issue in recent years, including in Germany. They are everywhere: in the water, in the air, in the soil and even in our food. But how do microplastics get into our everyday lives and how can they be detected in the body? We explain the problem and show how laboratory medicine is helping to shed light on the issue.

Where do microplastics come from?

In Germany, microplastics are produced in various ways. A large proportion comes from the abrasion of car tires, which gets onto the roads when driving and is then washed into rivers and soils by rain. Plastic waste that ends up in nature and slowly decomposes also contributes to this. In addition, there are tiny particles from cosmetic products such as scrubs or toothpaste, which often used to contain microplastics – although this is now banned in the EU, some older products are still in circulation. Even when washing clothes made from synthetic materials such as polyester, small fibers are released into the environment via wastewater. Sewage treatment plants filter out a lot, but not everything. Microplastics end up in rivers, oceans and ultimately in our food chain – for example in fish, mussels or even in drinking water.

Germans are increasingly aware of the problem. Studies show that microplastics can be detected in German waters such as the Elbe or Lake Constance. Traces have also been found in foods such as salt, beer and honey. So it is not a distant problem, but something that affects us directly.

How do microplastics get into the body?

Microplastics enter our bodies in various ways. The most common way is through food: when we eat fish or seafood, we often unknowingly ingest small plastic particles that the animals have swallowed. But microplastics can also end up in the air we breathe or the water we drink. Especially in cities, where there is a lot of traffic and industry polluting the air, these particles float around and are inhaled. Contact is even possible via the skin, for example through cosmetics, although this is less common.

Once in the body, microplastics don’t just stay there. The tiny particles can accumulate in organs such as the lungs, liver or intestines. Some are so small – so-called nanoplastics – that they can even penetrate cells. Whether this has health consequences has not yet been conclusively clarified. Scientists suspect that it could trigger inflammation or release harmful substances that adhere to the plastic into the body. However, in order to know this for sure, it must first be clarified how much microplastic is in us in the first place.

Detection by laboratory medicine: how does it work?

Laboratory medicine plays a crucial role in making microplastics visible in the body. This is not so easy, as the particles are microscopically small and often invisible to the naked eye. To find them, scientists and doctors use special methods that are precise and reliable.

The first step is to take a sample. Depending on the suspicion, various materials are examined: Blood, urine, stool or even tissue samples taken during operations. Stool is analyzed particularly frequently because microplastics enter the intestine through food and remain detectable there. The sample is then sent to the laboratory, where it is prepared – for example by filtering or chemical processing to separate the microplastics from other material.

State-of-the-art equipment is then used. One common method is known as Fourier transform infrared spectroscopy (FTIR). Here, the sample is irradiated with infrared light and the light pattern that comes back reveals whether plastic particles are present and what type of plastic it is – polyethylene or polypropylene, for example. Another technique is mass spectrometry, which can identify particularly small particles down to the nanoscale. Using such methods, researchers can not only say that microplastics are present, but also how much and where it could come from.

In Germany, studies have already shown that microplastics can be detected in the human body. A study from 2018 found tiny plastic particles in stool samples from test subjects from various countries, including Germany. This proves it: We actually ingest microplastics and laboratory medicine can make them visible.

What does that mean for us?

Microplastics are a problem that we cannot ignore. In Germany, researchers and politicians are working to reduce the sources – for example through better sewage treatment plants or stricter rules for plastics. But as long as it is in the environment, it will remain in our lives. Laboratory medicine helps us to understand the extent and assess possible health risks. Research is still in its infancy, but one thing is clear: microplastics are no longer a distant horror, but part of our everyday lives – and our bodies.

As invisible as the particles are, we can detect them with the right methods. This is a first step towards finding solutions – for the environment and for our health.

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Gender note. The personal designations used in this text always refer equally to female, male and diverse persons. Double/triple references and gendered designations are avoided for the sake of better readability ected.