The Sentinel Self
The Sentinel Self is an interactive and immersive artwork built in the game engine Unity. It reflects on the entanglements between human immune systems and environments increasingly polluted by microplastics.
Microplastics and Us
- essay by Heather Leslie, ecotoxicologist and microplastics expert
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Plastic technoexuberance
Plastics are the triumphant materials of the technoexuberant 20th and 21st centuries. Synthesized using oil refinery by-products, plastics have squeezed out traditional materials and taken over consumer society. Plastics feature in day-to-day business and many industrial processes. Oil isn’t the only feedstock for plastic production. A small fraction of plastics are now being produced from plant biomass. Another small fraction of today’s plastic comes from recycling waste plastic.
Meanwhile, we have all become a little bit plastic over the decades that carried us to our plasticized present. This happens through simply interacting with our stuff, wearing it, walking on it, carrying it, drinking from it, eating with it, sleeping on it, playing with it, communicating through it, building with it, flying in it, and imbedding it in our human bodies both intentionally and unintentionally.
Why is plastic here?
Plastic is cheap and easy to manufacture. Polymer chemistry drives plastic innovation and offers endless choices in designing new materials. Manufacturers saw a powerful way to make money and saw a great future in plastics. A relatively limited number of humans invented, developed, produced and then marketed plastic to the whole world. There are almost 10,000 different plastic materials on the market today. Used to make billions of products.
Plastic is complex stuff. Polymer chains are the molecular backbone of plastics. But you also find chemical additives, fillers, trace amounts of catalysts and impurities that no one added to plastic on purpose. Plastic is a bit like spaghetti noodles (polymer chains) in a chemical sauce. With age, the noodles break and fragment into smaller pieces, which encourages the chemical ‘sauce’ components to escape by either evaporating or leaching out. This happens continuously in big and small ways, fast and slow, indoors and outdoors, in in attics, cupboards, desk drawers, plastic jars, on the soles of our shoes and the wheels of our vehicles, in oceans, forests, parks and living bodies of all shapes, sizes and sorts.
The plastic stuff we make and use comes and goes. Every atom and molecule in our 3D world is vibrating and nothing is likely to stay put forever. Plastic stuff gets old, it breaks, it erodes, we lose it from our lives. It goes on to lead a life of its own. It’s not food so it doesn’t get digested by living things. And it doesn’t readily mineralize or participate in biogeochemical cycles. It follows its own programme. So the planet is stuck with it for the time being.
Why is it in our bloodstream?
Both the tiny chunks of plastic – ‘microplastic’ – and the chemicals from the sauce end up outside of the technological cycles, outside the products and processes it was intended for. Microplastics and chemical escapees from microplastics - they’re free from their original functions in our lives. They flow, they interact with nature, with biology, and with us. We breathe them in. We swallow them. In the air, water and food chain we can expect to encounter them. Who can avoid these, our life-giving air, water and food? Sometimes we absorb this pollution around us. Then we simply take it with us everywhere we go, inside our bodies. There’s much to say, think, feel and imagine about that. It’s also a scientific place where it gets toxicologically interesting.
When microplastic particles are tiny enough, they can bounce across biological membranes, such as in the human gut or even in the lungs. Instead of just passing though us, or being coughed up, they gain access to our inner bodily world. Our recent research has showed they are detectable in the human bloodstream, in the river of life[1]. Without our permission, these microplastic characters can travel around our circulatory systems. A hundred thousand kilometre blood vessel pathways. Being in blood, they gain access to the entire human body, all organs and tissues. Plastic is not only in our constructed consumer society and industry anymore. It is literally close to our hearts. Our human hearts that we depend on for so much that makes us human, intelligent, intuitive, understanding, aware and connected to each other.
Unintended consequences
When you know we’ve been plasticized, the very next question that arises might be: how bad is it?
Toxicologically speaking we know plastic triggers immune responses – our intelligent bodies figure out within seconds when microplastic is around. Immune system cells specialised in clean up actions know exactly how to clean up bacteria and junk from the bloodstream. Since the 20th century when plastic burst onto the consumer society scene, and soon after started to transform from products to pollution, these cells have another task to contend with. Microplastic.
In the human bloodstreams studied so far, it was typical to find a microgram of microplastic per millilitre of blood. If you consider a typical human body carries 5500 millilitres of blood around, that translates to around 5.5 milligrams of microplastic in one human body. How well can immune cells tackle microplastic? Imagine a whole human body, standing in front of you, smiling peacefully, maybe saying something friendly to you. What if you could zoom in on the body, zoom right in, close enough to see what’s going on in a tiny blood vessel? Immune cells would be at work. And microplastics have prepared themselves for the inevitable confrontations with their outstanding enzyme resistance.
Besides being a potential toxicological threat to health, there are other questions we can ask.
Are microplastics me?
What is my relationship with them?
Is microplastic pollution congruent with human dignity?
Is it aesthetic?
Did we say we wanted this?
Is this demonstrating our finest application of modern science and technology?
What has plastic brought to our society and what has it taken away?
Is our future microplastic polluted?
Which paths are available to us going into this future?
What other questions have we asked ourselves about plastic lately?
What answers do we have to these questions?
The questions matter most.
The answers will follow when we feel, think, intuit and imagine.
[1] https://www.sciencedirect.com/science/article/pii/S0160412022001258?via%3Dihub