«What are these plastic particles doing in our body? Where are they going?». In conversation with Prof Dick Vethaak on plastic particles being found in our blood
Recycled PET bottles could contain more chemicals than virgin plastic
A recent study found that recycled PET bottles could contain more chemicals than virgin plastic bottles. The analysis was done by researchers at Brunel University London. They looked into the migratory process of these chemicals throughout the lifecycle of PET. The team of researchers found that there are certain factors which affect the migratory process.
«These factors could be the physical characteristics of the bottle itself, or the way that it was produced», explains Dr Eleni Iacovidou, who led the study. She is a lecturer from Brunel’s center for pollution research and policy. «Other factors also include the geographical origin of it, the storage conditions or the reprocessing efficiency. This decides how the plastic bottles that are wasted are actually being reprocessed into secondary plastic materials».
They saw that there are certain chemicals within the system which should encourage a more cautionary treatment of plastic bottles once they are considered waste. This would ensure that the chemicals don’t return into the system when recycling them to produce secondary materials. The overall aim after this study is to bring stakeholders together to come up with future waste management solutions and improvements.
What is PET plastic and just how harmful is it?
Polyethylene terephthalate (PET) is the third most widely used plastic in the packaging sector. Iacovidou explains that this is due to its properties: it can be flexible but sturdy enough to hold liquid; it is transparent; and it acts as an oxygen and moisture barrier.
«PET is not more harmful than other plastics when you look at the chemicals. But PET is a single-use plastic. Because we dispose of it very quickly, there are large amounts of this plastic ending up in the environment», says Iacovidou. Dr Loula Gerassimidou is an Environmental Engineer who also took part in the study. She explains that this research was a systematic literature review.
This means that they collected the findings of previous studies and critically assessed them to obtain conclusions. «We don’t have sufficient evidence to make any substantial comments regarding the number and the level at which chemicals can migrate from recycled PET», Gerassimidou says. «What we found is that there are factors that can affect the migration of chemicals from recycled PET across the whole lifecycle».
The factors affecting the migratory process of chemicals
They saw that physical characteristics, such as design components, can affect the migratory process. This includes labels, glues and inks at the stage of production. Additionally, the researchers explain that the storage conditions can also affect the migration of chemicals.
This includes both the storage before being purchased by a consumer and after. Iacovidou gives an example of the plastic PET bottle being left in a hot car. When one returns to it and drinks from it, most likely there is a slightly different flavor. She explains that these are the chemicals which seep through into the liquid. The most crucial migratory process happens at its end-of-life stage.
When the PET bottle becomes waste, there is a high risk of cross contamination. This can happen when chemicals are transferred from other waste material. Depending on the conditions, the waste PET bottles could absorb certain chemicals from other waste. «We can’t say that there are more chemicals or that they are more harmful. But there are many factors that we can control to have better quality recycled PET bottles», says Gerassimidou.
Determining which types of chemicals could migrate to PET bottles: Bisphenol A (BPA)
The issue is not being able to determine exactly which chemicals can migrate to individual PET bottles. The way that they found out about the factors in the migratory process was determining which chemicals weren’t expected to be present at specific stages of the PET bottle’s life cycle.
«This means that they may have been inserted from other stages of the lifecycle such as that of consumption, storage or end-of-life stage», Gerassimidou explains. However, they did find the presence of Bisphenol A (BPA) in some of the recycled PET bottles. It is an endocrine disruptor which can be harmful to humans even at low doses.
This doesn’t mean that BPA is present in all recycled PET bottles. However, «the end-of-life stage with cross-contamination is the most influential factor in the migration of substances, such as BPA». In fact, Iacovidou explains: «There are plastics that are made with a large number of chemicals. For example, polycarbonate is made from BPA. So, you would expect to find that across the life-cycle of this plastic». Finding it in recycled PET however, indicates that the cross-contamination of certain chemicals does occur.
Waste management, cleaning solutions and storage recommendations
Gerassimidou suggests a number of ways to produce good quality and safe plastic bottles from recycled content. «We need to adopt a wide range of changes across the entire value chain». For example, at the stage of production, there needs to be transparency in the physical characteristics which manufactures plan on giving the product.
«This is to avoid the use of hazardous chemicals and to have a controlled selection of labels, inks and other design components. We also need to monitor the presence of chemicals at the stage of production. There may be impurities of chemicals even in the raw materials or machinery», she says.
Processing machinery which is insufficiently cleaned could be a setting for further cross-contamination. Monitoring the storage conditions during distribution and transportation is also important to take into consideration. Suggestions such as keeping the bottles in a cool and dry place should be followed.
There should also be a change in consumer habits to avoid the misuse of these bottles, further risking cross contamination. Finally, there should be an improvement in the collection of PET bottles which are meant to get recycled.
This includes traceability mechanisms to control this. The research highlighted certain areas when it comes to the probability of humans ingesting plastic and chemicals particles. However, a pioneering study found just how far we can find plastic particles in our body.
Plastic particles found in our blood
Prof Dick Vethaak is an ecotoxicologist at Vrije Universiteit Amsterdam in the Netherlands. He and his team detected and quantified a number of plastic particles in blood streams. They focused their study on five commodity plastics.
It is considered as a breakthrough discovery which needs to be extended. This particular study took about three years to do and looked at twenty-two healthy donors. They found plastic particles in seventeen of their blood. «One of the big issues that we faced was having to do the analysis in a plastic-free way», Vethaak explains.
In fact, their experiments had to be conducted in a completely sterile and plastic-free laboratory to avoid contaminating the sample. Once they extracted the blood from the donors, they immediately transferred it into a glass tube. It was then sealed with a rubber tap.
Whilst this is classified as a type of plastic, Vethaak explains that they didn’t measure that particular polymer type so they could exclude it from the analysis. Throughout the entire process, they made sure to use petri-dishes to act as controls in the experiment. This was to see that what they were measuring at the end of the day was not coming from the air or from clothes, but from inside the body.
What can you do to avoid inhaling plastic particles?
In discussing past research, Vethaak mentions that there is a higher concentration of nano-plastics found inside houses. This is particularly due to house dust. The deposition of this dust can result in not only inhaling these particles but also ingesting them.
Vethaak suggests to therefore ventilate your house as well as covering food if not consumed immediately. He also recommends not heating up food in a microwave with a plastic covering, not buying cosmetics with microbeads and not heating up drinks in plastic cups or bottles.
The limitations of the study and further questions
Whilst they did find evidence of plastic particles in blood streams, there were a number of limitations in the study. The first being the relatively small number of donors for such an extensive experiment. Another one is the uncertainty of when the plastic particles ended up in the blood. Vethaak explains that it could have something to do with the recent exposure.
For example, did that particular donor drink coffee from a plastic cup that morning? «Research needs to go much broader in terms of the number of donors, and also the backgrounds and lifestyles of people», he admits. Additionally, there are a number of new questions which they now want answered.
For example, just how much do plastic particles contribute to illnesses and diseases? «All ambient particles, regardless if it is plastic or not, can cause things like chronic inflammation. So we have to see how much these plastic particles contribute to the total particle load in the body», Vethaak clarifies.
«Maybe these particles have a very unique toxic profile because they may have very different chemical additives». In fact, plastic particles are not just one compound. They are a class of highly complex contaminants. They are of different sizes, shapes and composition.
«Air pollution is one of the biggest killers worldwide. Plastic dust is a component of that. But we have to find out how much of a percentage that is». Other questions which the study has brought up according to Vethaak include: «What are these plastic particles doing in our body? Where are they going? What fraction is excreted? How much is retained in the body? Is it accumulating somewhere? Can the small particles reach the placenta?». This research is currently already getting extended to find out more.
Future studies on plastic and possible solutions
Regardless of what future studies find out and what policymakers are willing to do about it, plastic is simply too convenient to completely ban forever. In fact, Vethaak distinguishes the good plastics from the bad ones. The good ones include those used in the medical field, such as tubes and other durable equipment.
The bad ones include single-use plastics, such as PET. The lack of awareness and regulation surrounding these plastics is something which both teams believe need to be worked on. «We need to address these gaps in order to close the loop of PET bottles. Other than their use and presence, the problem with plastic is the bad management», Gerassimidou says.
These two studies are at the early stages, requiring further tests, experiments and assessments to form better conclusions. However, some things are certain. The first, is that «the risk is underestimated because there is no guidance by authority for a risk assessment», explains Iacovidou.
«Their assessments are based on very limited toxicity data which is associated with high uncertainty. We need advanced analytic and exposure assessments», she continues. Whether or not in-depth studies will follow suit to find more detailed explanations, Vethaak does point out that it «will take another ten years before we can obtain enough evidence to bring to policymakers».
Dr Eleni Iacovidou
Lecturer in Environmental Management. One of her focus areas is plastic and plastic packaging system assessment
Dr Loula Gerassimidou
Doctoral Researcher in the School of Civil Engineering with a focus on Solid Recovered Fuel
Prof Dick Vethaak
European Registered Toxicologist and a part-time professor of Ecotoxicology at the Institute for Environmental Studies. He has more than 30 years experience in the field of ecotoxicology and water quality issues of delta and marine waters.