Scientific and informative day promoted by the Microplastics on Human Health Committee with the municipality of Milan
This is the second annual outreach conference on micro- and nanoplastics, organised by the Microplastics on Human Health Committee in collaboration with the Municipality of Milan.
Last year’s conference opened the conversation — covered in a three-part series: Part 1, Part 2, and Part 3.
Why this event? Because scientific knowledge is often poorly communicated. Misinformation is widespread.
This topic spans multiple domains:
• effects on human health
• the biological world
• the industrial world
• disposal and reuse of plastic
• the fashion world
The goal is simple but essential: to share accurate information with the public and with institutions.
You can watch the event here.
The weight of things: a brief history of anthropogenic mass
Telmo Pievani – professor of philosophy of biological sciences, University of Padua.
He opens the panel.
What is plastic?
He starts with a quote:
“The material that nature forgot to invent.”
On one hand, it’s a sign of human inventiveness — the creation of a democratic material. On the other hand, it also has a dark side: if nature didn’t invent it, it means there are no bacteria capable of destroying it.
How long have we been inventing materials that nature forgot to invent?
We have become physiologically dependent on technology. Just think of something as basic as cooking.
We changed the world through technology, and we have become dependent on it.
Now, we must learn to interact with nature in a virtuous way.
The problem is time. Let’s consider the human impact on the environment: from the 1950s onwards, there has been a great acceleration. In the last three generations, the human impact on the planet has gone out of control.
The weight of human artefacts used in our lives has exceeded the combined weight of all the plants, organisms, and microorganisms on Earth.
(Ron Milo, study published in Nature, December 2020).
If we continue like this, by 2050, there will be more plastic than fish in the sea.
We must learn to make peace with nature.
Nature-based solutions — as explored by Frances Arnold. She has found enzymes capable of reducing pollutants.
So, back to where we started: this, too, was not invented by nature, but it is a solution. Harnold exploited evolution to produce an enzyme that nature hadn’t invented. Researchers are now looking for bacteria capable of degrading plastic.
The attractiveness of plastic and its environmental implications, with particular reference to water
Nicoletta Ancona – Curator of the Aquarium and Civic Hydrological Station of Milan.
Plastics — what are they?
Polymers — very long chains. Many different substances that we group together under a single name.
They have responded to human needs in every circumstance, as they are very cheap materials. The main problem issingle-use plastic — it degrades very slowly. Therefore, its use must be severely limited.
Plastic production is rapidly increasing. But where does all this plastic end up?
Only a tiny portion is recovered. The rest is dispersed everywhere, through the water cycle. Concentrations of plastic are found everywhere.
Microplastics are the most damaging. Micro- and nanoplastics are much less visible but make up a significant portion of our diet. It starts with filter feeders — oysters, shellfish, whales — so they enter the food chain.
There are also substances that bind to plastic and amplify its harmful effects.
So, there is an ethical and health issue. It is important to inform, raise awareness, and educate. Let’s start from the bottom — from our daily lives — to limiting plastics.
A striking note:
It’s sad to hear that in a facility like the Aquarium, they still use plastic cups for coffee. Due to existing agreements, bla bla bla… When we say the system is designed to fail, are we really wrong?
The hidden threats of plastics on human health
Prof. Claudio Fenizia – Professor of Immunology, University of Milan
Threats of plastic to human health. Highlighting the critical issues.
How plastics enter the body:
Plastics enter through inhalation, food, food and beverage containers, food storage containers, and transdermal application.
Plastics have been found in blood, testes, placenta, and amniotic fluid.
What is the effect?
• In atherosclerotic plaques, a higher concentration of plastic corresponds to greater inflammation.
• Plastic has been found in tumour tissue.
• A higher amount of plastic in the brain corresponds to a higher proportion of individuals with disorders such as senile dementia.
But – and this is key –
Until the causal mechanism is identified, the effect cannot be demonstrated.
Or rather: it must be defined whether plastic is the cause or the effect of inflammation or disease.
Environment, water and health
Prof. Caterina La Porta – Professor of Pathology, University of Milan
The environment we live in determines our health. A single vision of health emerges — One health.
Water is one of the most important vectors of exposure. We drink. We bathe. We wash our clothes. Everything in the environment reaches us.
Heavy metals, pesticides, and organic compounds accumulate in the environment.
This isn’t just an environmental problem — it’s becoming a health issue.
Regarding the impact of micro- and nanoplastics, we need to determine whether there is correlation or causality. Whether there is a single effect or bioaccumulation.
The microbiota — the complex network of bacteria, fungi, and viruses present in our intestines — is key.
Studies are being conducted to understand what happens with microplastics, which function as a concentration of toxic substances.
Climate change multiplies the risk. For example, drought increases concentration.
Education means making it clear that there is a problem. And making the right choice together.
What kind of future do we want?
Are PFAS and plastics really eternal pollutants?
Prof. Edoardo Puglisi – Professor of Agricultural Microbiology, Catholic University of the Sacred Heart, Cremona
The question — which may seem philosophical, but it’s a scientific one — concerns whether we can solve the problems posed by these invaders.
First, a distinction: pollutant vs. contaminant.
When we talk about pollution, we use the words pollutant and contaminant in the same way, as synonyms. Technically, they are two different things.
• Contaminant: a natural or man-made substance that reaches a certain threshold.
• Pollutant: when that substance reaches levels high enough to cause adverse effects.
Another related issue is natural vs. synthetic substances.
There’s a tendency to think that natural substances are less toxic, but this isn’t always true.
We must have a scientific approach that allows us to understand how and to what extent substances can be dangerous.
Some natural substances are much more toxic than chemical ones.
In science, it’s best not to have multiple words that mean the same thing.
Another key distinction: danger vs. risk
• Danger: a substance that is toxic and can be dangerous to humans and the environment.
• Risk: depends on exposure. Risk combines danger and exposure. How much we are exposed to these substances. Risk assessment involves addressing these two elements.
A tiger can be dangerous, but the risk depends on the exposure.
The same goes for pollutants.
As a microbiologist, the answer he tries to give as to whether PFAS are truly contaminants starts from the observation of microorganisms. These are the oldest organisms on Earth. They are a constant with an enormous capacity to adapt, even to new invaders.
New substances are called xenobiotics — substances that have never existed on Earth. Like PFAS, like plastics.
Organisms were unaware of them, but they learned to interact with them.
Microorganisms are, therefore, allies in remediation. If we are dealing with an organic pollutant, microorganisms can learn to degrade and consume it.
There is a coevolution between microorganisms and the xenobiotics existing in the environment. New metabolic pathways are developing that can lead to degradation.
What are PFAS?
PFAS are a highly heterogeneous family of chemical molecules containing a covalent bond between carbon and fluorine. They are called “eternal pollutants” because they are difficult to degrade.
PFAS and microplastics move through the environment and enter humans. Plastics tend to become micro- and nanoplastics. The smaller they are, the more they tend to accumulate.
Plastifera, the communities of bacteria and microscopic fungi that have learned to colonise plastics. The degradation of plastics is still very limited. But fungi are beginning to degrade plastics.
Remediation is possible
PFAS can be remediated. The costs are high, but the costs associated with pollution are even higher.
There are enzymes that have learned to colonise PFAS.
Case study: Veneto
In Veneto, there has been a significant accumulation of PFAS in water and the environment. A study is underway to identify degradation genes.
His conclusion:
He is confident that solutions can be found to degrade PFAS.
Micro and nanoplastics — closing notes
If by 2050 we’ll have more plastic than fish in the sea, these bacteria need to hurry up.
From Pievani’s “material that nature forgot to invent” to Puglisi’s microbes slowly learning to eat it, one thing is clear: nature is trying to catch up. But time is not on our side.
We left the panel with more questions than answers—
Not just about causality and bioaccumulation, but about who to trust. Greenwashing wasn’t mentioned by name, but it hung in the air like the plastic cups of the Aquarium.
—
Coming Wednesday:
Micro and nanoplastics: what can we actually do? From daily choices to institutional action.