Drinking water, human placenta and atmosphere: where else will scientists find microplastics, and what does it mean for us and the upcoming generations?
The global ecosystem is a site of «accumulation of plastics in the environment. Animal and human organisms are affected by this hazard, even if to date, no scientific evidence of long-term effects, such as chronic diseases, have been reported». Prof. Elisabetta Giorgini and Dr. Valentina Notarstefano are both at the forefront of understanding and attempting to reveal more about some of these plastics that we evolve within. The first is an Associate Professor and head of the Laboratory of Vibrational Spectroscopy at the Department of Life and Environmental Sciences, Università Politecnica delle Marche in Ancona, Italy. The second is a post- doctoral researcher in the same Department. Their team along with a larger alliance of scientists at the San Giovanni Calibita Fatebenefratelli Hospital in Rome, has revealed for the first time the presence of microplastics in human placenta. The results had a great impact, both in the scientific community and among responsible citizens «who are interested in the quality of the environment they live in», as Giorgini explains. This finding questions the influence of these particles on the wellbeing of all ecosystems around the world. Microplastics are plastic fragments of man-made origins, with dimensions ranging between five millimeters and 0.1 micrometers. 320 tons of plastics are produced every year and, among these, forty percent is single-use products. This, «together with the incorrect disposal of plastic waste, has brought to a ubiquitous contamination of the environment. Another concern is given by pigments used for plastic products, paints, adhesives, plasters and coatings», explains Dr. Notarstefano. Microplastics can be divided into «primary, which are intentionally produced in micro-sizes for commercial uses, and secondary, resulting from environmental degradation of larger fragments; atmospheric agents (waves, abrasion, ultraviolet radiation, photooxidation), in combination with bacteria, can degrade plastic fragments into micro and nano-sized particles» continues Professor Giorgini. For humans, the routes of exposure to microplastics are numerous. In particular, the most impacting one is ingestion with food and beverages; it is estimated that one person can ingest 39,000-52,000 microplastics per year. The duo explain that another route of exposure, not always considered by people, is through contact with personal care and cosmetics products, such as toothpaste, scrubs, and glitter make-up products.
Microplastics found in human placenta
Finally, microplastics can also likely be inhaled, potentially reaching the alveoli of the lungs. Their description of this landscape of continuous toxicity reveals routes, sites and methods to face and better understand the microplastics in our world. The scientists explained the importance of building on other scientist’s research to better understand this landscape, Dr. Notarstefano states that research on microplastics is «heterogeneous both in terms of nature of the investigated samples (marine sediments, animal tissues, food, beverages) and dimensions of retrieved microparticles». Apart from microplastics with millimetric dimensions, which can be detected by visual inspection, those of micrometric size can be revealed only by microscopy techniques. Moreover, in recent years, these techniques have been coupled with vibrational spectroscopies, which also enable their chemical characterization. The scale of microplastics is so small that it is hard for us (who do not use microspectroscopy) to have a good conception of the nature of these plastics. To be able to render them visible for the masses, the scientists used a top-quality instrumentation, including FTIR and Raman microspectrometers. These techniques allow for the optical microscope, with a very high magnification, to detect the presence of possible man made microparticles. To identify them, the team irradiates the detected particles with a laser light, and then correlates the induced vibrations with their chemical composition. As it happens for every experiment set up, restrictions in the tools exist and this might explain why speculating and further research is the only way to understand these microplastics better. Professor Giorgini understands that «it is difficult to relate these dimensions to make everybody visualize them. As an example, we usually say that this is the same as a human red blood cell, or we can relate it to a human hair, which has a diameter of around fifty to seventy micrometers».
Dr. Notarstefano clarifies: «although the placenta can be considered as one of the several organs we could have chosen to analyze in the human body, the importance of its selection relies on three aspects: first, its short life of nine months, in respect to other organs; second, the role of the placenta in creating a barrier between the fetus and its external environment which could be harmed by the presence of man-made particles and lastly, highlighting a tangible hazard that could possibly come at the expenses of babies in the womb, triggers a shock reaction». Professor Giorgini continues, «we have to be scientifically honest, no evidence is present of a correlation between this discovery and a possible danger to babies: our results are just that microplastics can be found in the human placenta, hence every other hypothesis is just a hypothesis and needs to be further studied and proved». What this research has brought forward is that «microparticles and microplastics in the placenta, together with the endocrine disruptors transported by them, could have long-term effects on human health». Plastic materials and, hence microplastics, contain additives that are used for their production, among which the most famous are plasticizers. These chemicals are employed to provide specific properties to plastics, such as elasticity, and comprise the well-known phthalates and bisphenols. It is known that unbound BPA (bisphenol A) can be easily released from plastics. The endocrine disrupting activity of microplastics are «capable of interfering with hormone pathways, affecting, for example, reproduction and metabolism», reinforces Giorgini.
The sea: the most impacted ecosystem by plastic
Fortunately, not all the microplastics introduced into our bodies are accumulated. The scientists clarified that once internalized by the exposure routes most microplastics are eliminated for example, by feces. Both in animal and human bodies, numerous evidences are reported that a fraction of very small microplastics (smaller than ten micrometers) is absorbed by the organism: through the intestinal epithelium, or the respiratory tract. Microplastics end up in the bloodstream. Their research from here on is focused on the characterization of microplastics both in marine species and human breast milk. «The sea is the most impacted ecosystem with regards to plastic contaminants and hence evaluating the presence of microplastics in commercial fish, such as swordfish or tuna, could better define the risk to which we are exposed daily», highlight the duo. They stress the importance of working with researchers in similar but slightly different fields, such as Professor Oliana Carnevali, who works in the field of Reproductive Biology. A key lesson for us to think about in all fields is that mankind must start designing a world not only at the disposal of human needs, but also thinking of the wellbeing of all organisms. Professor Giorgini continues: «the choice to disregard the contamination of the marine environment and sea life, means not wanting to become aware that eating the sea food we love, also contaminates our bodies». This last point made by the scientists reveals another site of accumulation and transit of toxicity: the ocean.
The Pacific Trash Vortex
In this landscape of accumulating toxicity, exists the Pacific Trash Vortex. This is a ‘plastic island’ that pans the waters from the West Coast of North America to Japan. «For a long time, it has been this far away thing, an island of trash in the Pacific, and when we found it in drinking water in 2017, it caused alarm bells to go off in people’s minds. When I talk to people that are non-scientists about microplastics, almost everyone has the same reaction of ‘I don’t want that in my water’», says Dr. Scott Coffin, a Research Scientist at the California State WaterResources Control Board. This accumulated ‘island’ of microplastics stands as an archive of the toxicity in our oceans. Microplastics are transported by both wind and water, as well as other processes both natural and human. Between two to five percent of these microplastics find their way washed into the ocean, settling on the seafloor and drifting in layers of water. This process endangers marine life. Coffin became aware of these landscapes of toxicity when studying microplastics in Costa Rica. He was just an eco-tourist, speaking of garbage accumulation on beaches. This then prompted him to start his Ph.D. on Ecotoxicology in California. There, Coffin studied the ecological impact of plastics before focusing on human health. The first conclusions on microplastics in drinking water were published shortly after Coffin had graduated. The researcher explained that «within months, the Californian legislature passed a bill that required us to investigate the issue, provide a little finding and an impetus to develop a method, look at the health effects, and to understand the extent of the problem in California’s water system». Similar to the Italian scientist duo, Coffin and his team have to work around the issue of defining microplastics to better understand the scope and sites of accumulation they are interested in revealing. Coffin remembers, «the problem begins with the word ‘microplastics’ alone, since, before June 2020, there was no legal definition of the term, which created limitations for the research». The institute where he works, the Water Boards defines it in a more nuanced way than that explained by Professor Giorgini. The Water Boards – State Water Resources Control Board’s mission statement is to «preserve, enhance, and restore the quality of California’s water resources and drinking water to protect the environment and public health». The institute defines microplastics as «solid polymeric materials to which chemical additives or other substances may have been added, are particles that have at least three dimensions, greater than one nanometer and less than 5,000 micrometers. Polymers that are derived in nature that have not been chemically modified (other than by hydrolysis) are excluded». The Water Boards also did not want to exclude the «toxicity to human materials preemptively». While the plastic industry wanted to narrow down and constrict the definition, Coffin explained that the institute attempted to «expand it because of the lack of information on the particles’ safety, especially when synthetic and non degradable». Settling on this definition allowed Coffin and his team to look deeper in comparing the particles’ sizes. «When anything is above ten microns/micrometers, you can breathe it in, but it will be coughed out». Coffin shared similar uncertainties with many scientists about the scale and effects of micro- plastics in our bodies.
Microplastics released by textile fibers
Following the Plastic Soup Foundation, approximately sixteen percent of the plastic, produced in a year consists of textile fibers. As production rises, the percentage goes up accordingly. Synthetic clothing production spreads plastic in the drinking water and makes the ingestion of household dust common. Coffin highlights that «below this number is where you start to see the biological effects. One way that you can think of the impacts of these microplastics, especially the fibers, is their similarity to basters. Basters are small fibers that can penetrate cells and break them apart. Our immune system crudely responds to these by trying to encapsulate the fiber and break it apart by emitting what is called ‘reactive oxygen species’. It is like a bomb; when the bomb goes off, it does not break down the particle because it is stable. That bomb damages the cell itself, and it can cause DNA damage, which will progress eventually to cancer. We have evidence for those effects with microplastics in humans through occupational studies, but we do not know how it translates to drinking water or the smaller doses that we see in the general population». Coffin and his team are concentrating on identifying sites of the accumulation of microplastics in this toxic landscape. These microplastics «end up in drinking water through a river, reservoir, or lake, and some of them will make it through the wastewater treatment system». He reached the conclusion that «at this point, we have more plastic mass than all of the animals combined in the world». He later identified roads as another site of accumulating toxicity.
The problematic lifespan of plastic
The Water Boards’ research stressed the fact that storm water washes the particles from the roads into rivers, considering that tire wear particles were the most toxic thing found during their research. Coffin and his colleagues have also put forward solutions. In the case of tire wear for instance, the SFPUC Green Infrastructure program focuses on planting plants that are specifically designed to capture pollutants along the roadway. The solution should «not focus only on additive approaches but also on cutting plastic production». The U.S. Environmental Protection Agency shared that twenty-seven million tons of plastic were sent to landfills in 2018, while Plastic Oceans estimates nearly 300 million tons of plastic are produced each year, fifty percent of which are single-use products. The problematic lifespan of plastic was highlighted in the research. Any alternative such as hemp or biodegradable plastic will reduce the amount of plastic pollution. Coffin reflects on this reality by drawing a parallel, «we may end up replacing one devil for another, as some of the biodegradable plastics degrade rapidly» in contrast to other plastics that last one hundred to 2000 years. The solution, Coffin stresses, is source control and reducing our consumption. «There are some products like medical supplies for which it is difficult to find a replacement, but other things like plastic utensils or take out containers, we can replace with degradable paper products or starch corn made packages» suggests Coffin. The Water Boards is currently working on «developing a standardized method to test the water. This method is currently being evaluated by about thirty five labs in seven different countries». The third part of this research is determining what the health effects are and «how much is too much», states Coffin. Scientists looking at microplastics evidently seem to share limitations in the process. Coffin explains, «we do not have methods that can reliably characterize these types of particles like the submicron and the nanosize plastics. From the literature, we believe that the most toxic particles are below one micron, and the method that we are currently developing gets down to one micron, which is just the range where it starts to raise concern. Regardless of what we do within the state of our method, we are still going to be scratching the surface of this issue».
Plastic pollution in agriculture
The fundamental scientific limitations in particular, is the behavior of light that prevents the researchers from looking below the one micron as explained by both Coffin and Notarstefano. Coffin continues by stressing that «before putting energy in new findings, the human mindset should be focused on tackling this issue. To transmit the emergency level in plastic production to society, governmental bodies should design policies that focus on decreasing single-use consumption». He is working with the Ocean Protection Council, which is built on a legislative chart that tackles the «microplastic issue and focuses on policy applications that the government can directly implement» looking at upstream solutions from product redesign, distribution to wastewater treatment plants. At times, the wastewater treatment system locates the issue from one place to another. The Water Boards have defined that «nearly all of the microplastics that are not discharged through water, about ninety eight percent, are taken up into biosolids that are often applied to agricultural fields as a way of regenerating the nutrients because they contain nitrates and phosphates. These microplastics particles accumulate in agricultural fields». Coffin explains that earlier last year, «we discovered that plants could uptake microplastics particles through their roots and be distributed throughout the plant. We do not know whether this makes it into the fruits or vegetables that we eat, but we know that it causes plant toxicity. Over time you will see reduced food yields from farms. In the shorter term, we already see toxicity in soil ecosystems: worms, insects, even down to bacteria level – fungi, are being affected by these microplastics particles, likely at a higher risk than anything in the ocean. It is so recent that the scientific community has not yet grasped that».
Plastic pollution – a call to action
In 1907, the first synthetic plastic called ‘Bakelite’ was produced, since then plastics have grown in production. The Polyethylene terephthalate used today in packaging foods and beverages, especially convenience-sized soft drinks, juices and water, was first introduced in the Forties. It has since shaped the circuits of global plastic toxicity. Around the end of the last century, scientists had already demonstrated microplastics’ presence on human lung tissue and «presumed it as one of the cancer causes». This century-long plastic production, consumption and scientific analysis makes new findings even more possible in the near future. Scientists across the globe, looking at microplastics are essentially forming an elaborate landscape map of toxicity. The sites of accumulation of microplastics are revealed in human and animal bodies, but also in oceans, roads, water bottles and newborns. These ‘global ecosystems’ as described by Professor Giorgini are sites of constant toxicity. The scientists’ research showcased here feed of each other’s limitations and progress. Both Coffin and Professor Giorgini and their colleagues have shared a call to action. Notarstefano explained that publishing their research and sharing it with others is a way to make us all more responsible. It is also a way to call for «civil society to regain trust in science, and how scientists should be more predisposed to interface with common people and act as a driving force». Scientific evidence can guide us all in the choices we make in our society and in our fields; from design to fashion, to agriculture and politics. Microplastics reveal the challenges our global ecosystems have yet to uncover.
Dr. Scott Coffin
Environmental Toxicologist and Research Scientist at the California State Water Resources Control Board.
Professor Elisabetta Giorgini
Associate Professor and head of the Laboratory of Vibrational Spectroscopy at the Department of Life and Environmental Sciences, Università Politecnica delle Marche in Ancona, Italy.
Dr. Valentina Notarstefano
Postdoctoral researcher at the Department of Life and Environmental Sciences, Università Politecnica delle Marche in Ancona, Italy.