Hazardous microplastic and ways to reduce our exposure
Plastic is a material that consists of various synthetic and semi-synthetic organic compounds. The most produced types of plastic are polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET) and polyvinyl chloride (PCV).
Annually, over 320-360 million metric ton of plastic is produced worldwide, and the production is increasing due an easy and low-cost production and wild range of application. When buying products containing plastic it is important to bear in mind that over time these products release microscopic particles leaving them in the air, water, soil, and finally in our bodies.
WHAT ARE MICROPLASTICS?
Microplastic is formed through the processes of aging and fragmentation of plastics, their mechanical abrasion, the influence of solar radiation, oxidation, and microorganisms on the surface. Microparticles (size 1-5 mm) come from the consumer products like fibres, textiles, personal care products, cosmetics, cleaning products, paints. Nanoparticles (less than 1 micron in size) result from further fragmentation of microplastic.
Products of plastic degradation are chemically complexed mixtures. Many additives like stabilizers, fillers, pigments are added to impact the properties of synthetic materials. Most of them are hazardous to humans and the environment, such as phthalates, bisphenol A (BPA), polybrominated diphenyl ethers (PBDE), tetrabromobisphenol A (TBBPA).
HOW MICROPLASTIC CAN GET TO THE BODY?
Microplastic can enter human body via several routes. Oral intake is the most common one. Small plastic particles are already present in fish, sea food, salt, food packed in plastic, water, and beverages (especially the one in plastic bottles). Annually, we consume between 39-52.000 particles depending on age and gender. Absorption of microplastic occurs in the gut epithelium, pass through the liver, and are distributed throughout the body via the circulation.
Airborne particles are also an important source of microplastics. The inhaled particles may be swallowed or inhaled. The inner surface of human lungs is lined with 1 micrometre (1 μm) thick epithelium, which allows nanoparticles to penetrate the alveoli and through capillaries enter the bloodstream. Alveoli are tiny balloon-shaped structures where the lungs and the blood exchange oxygen and carbon dioxide during breathing. Alternatively, airborne microplastic can be deposited on food and drinks during consumption.
Other route of exposure includes the skin absorption due to the use of products made from plastic or stored in synthetic materials (like cosmetics).
It is also important to mentioned that the microplastic can enter the bloodstream of unborn baby. It has been found that synthetic particles enter the placenta through mother’s gastrointestinal and respiratory tracts (Arumugasaamy et al., 2019; Ragusa et al., 2021).
HEALTH RISKS OF MICROPLASTICS
Based on animal (in vivo) and cell (in vitro) data microplastic can generate free radicals and oxidative stress, change gene expression, increase inflammatory processes, induce endocrine disruption, reproductive and neuronal disorders, and behavioral dysfunctions (Prietr et al., 2014; Schirinzi et al., 2017; Magri et al., 20018; Wu et al., 2019; Poma et al., 2019). Microplastic with a diameter of about 5 microns can remain in the gut or liver. Molecules below 1.5 micron can cause systemic toxicity in different body systems.
Microplastic can generate immune dysfunction and lead to autoimmune diseases (reviewed in Frahat et al., 2011). It also increases production of pro-inflammatory cytokines like IL-6, TNF-alfa and histamine (Hwang et al., 2019). Moreover, small plastic particles increase the risk of neurodegenerative diseases like Alzheimer disease and dementia (Chen et al., 2017; Ranft et al., 2009).
HOW TO DECREASE THE RISK OF EXPOSURE TO MICROPLASTICS
You can decrease the risk of microplastics exposure and therefore, the risk of serious health complications due to small plastic particles, in many ways. Try to:
Buy food and personal care products packed in paper or glass containers.
When shopping, do not use plastic bags but take with your reusable textile bag.
Whenever possible, drink filtered water and limit the intake of water packed in plastic bottles.
Do not warm the food (also milk for babies) in plastic containers and especially not in microwave.
Do not store leftovers in plastic boxes but replace them with glass containers.
Try to choose safe toys for kids without many plastic parts.
If possible, choose natural cosmetics packed in glass containers.
Ventilate your home and workplace regularly.
If possible do not install vinyl or linoleum floors and limit plastic decorations (like plastic flowerpots).
Microplastics are solid plastic particles composed of mixtures of polymers and functional additives. Microplastics get into the human body and begin circulating, they can endanger health. Specifically, microplastics may negatively impact the human immune, endocrine and digestive systems. Microplastics have been shown to cause damage to human cells, including both allergic reactions and cell death. It is therefore critical to avoid exposure to plastics and minimalize their use.
Arumugasaamy N, Navarro J, Kent Leach J, Kim PCW, Fisher JP. (2019). In Vitro Models for Studying Transport Across Epithelial Tissue Barriers. Ann Biomed Eng. 47(1):1-21.
Chen H, Kwong JC, Copes R, Tu K, Villeneuve PJ, van Donkelaar A, Hystad P, Martin RV, Murray BJ, Jessiman B, Wilton AS, Kopp A, Burnett RT. (2017). Living near major roads and the incidence of dementia, Parkinson's disease, and multiple sclerosis: a population-based cohort study. Lancet. 389(10070):718-726.
Farhat SC, Silva CA, Orione MA, Campos LM, Sallum AM, Braga AL. (2011). Air pollution in autoimmune rheumatic diseases: a review. Autoimmun Rev. 11(1):14-21.
Hwang J, Choi D, Han S, Choi J, Hong J. (2019). An assessment of the toxicity of polypropylene microplastics in human derived cells. Sci Total Environ. 684:657-669.
Magrì D, Sánchez-Moreno P, Caputo G, Gatto F, Veronesi M, Bardi G, Catelani T, Guarnieri D, Athanassiou A, Pompa PP, Fragouli D. (2018). Laser Ablation as a Versatile Tool To Mimic Polyethylene Terephthalate Nanoplastic Pollutants: Characterization and Toxicology Assessment. ACS Nano. 28;12(8):7690-7700.
Poma A, Vecchiotti G, Colafarina S, Zarivi O, Aloisi M, Arrizza L, Chichiriccò G, Di Carlo P. (2019). In Vitro Genotoxicity of Polystyrene Nanoparticles on the Human Fibroblast Hs27 Cell Line. Nanomaterials (Basel). 9(9):1299.
Prietl B, Meindl C, Roblegg E, Pieber TR, Lanzer G, Fröhlich E. (2014). Nano-sized and micro-sized polystyrene particles affect phagocyte function. Cell Biol Toxicol. 30(1):1-16.
Ragusa A, Svelato A, Santacroce C, Catalano P, Notarstefano V, Carnevali O, Papa F, Rongioletti MCA, Baiocco F, Draghi S, D'Amore E, Rinaldo D, Matta M, Giorgini E. (2021). Plasticenta: First evidence of microplastics in human placenta. Environ Int. 146:106274.
Ranft U, Schikowski T, Sugiri D, Krutmann J, Krämer U. (2009). Long-term exposure to traffic-related particulate matter impairs cognitive function in the elderly. Environ Res. 109(8):1004-1011.
Schirinzi GF, Pérez-Pomeda I, Sanchís J, Rossini C, Farré M, Barceló D. (2017). Cytotoxic effects of commonly used nanomaterials and microplastics on cerebral and epithelial human cells. Environ Res. 159:579-587.
Wu B, Wu X, Liu S, Wang Z, Chen L. (2019). Size-dependent effects of polystyrene microplastics on cytotoxicity and efflux pump inhibition in human Caco-2 cells. Chemosphere. 221:333-341.