Aquafil, one of the world’s leading players in the production of synthetic fibers, and CNR-STIIMA developed a standard protocol for measuring the release of microplastics. The standardization project, supported by UNI, was positively received by the CEN TC248 and ISO TC3 textile commissions.
Million tons of plastic dumped in our oceans.
The serious problem of plastic waste
“Plastic”, from the Greek “plastikos”, that is suitable for molding, due to the intrinsic prop-erties of the material, such as malleability and, indeed, plasticity. Films, fibers, sheets, tubes, bottles, boxes, many shapes and many uses ranging from household to industrial. 389 million tons of plastic and, consequently, an equal amount of waste, is the figure that emerged in the 2018 annual report, published on the website https://plasticseurope.org/ .
It is estimated that of this plastic waste, currently there are about 150 million in our oceans, with an average annual increase ranging from 4.8 to 12.7 tons. The Pacific host a new “plastic island” covering the equivalent area of Spain and Portugal combined. And so, between consumerism and capitalism, man managed to replace nature, bringing out a plastic island next to the existing islands of the Pacific Ocean. The “Pacific trash vortex” or “Great Pacific garbage patch” is a huge accumulation of floating waste the size of the entire Iberian Peninsula, composed mainly of plastic materials, located in the Pacific Ocean, approximately between 135º and 155º West meridian and between 35º and 42º North parallel.
Despite the growing ecological awareness and an international policy that is trying to find and give adequate answers, the problem of plastic waste persists with the dramatic con-sequences known to all, from the death of many fish, with the consequent contraction of the economy based on fishing, to the pollution with all the negative effects on climate and tourism. The EU has adopted a total ban on single-use plastic items, including cotton buds, cutlery, plates, straws, sticks, polystyrene fast-food containers as well as an obliga-tion, by 2025, to reuse by 25 % of plastic recycled to produce plastic bottles.
From plastic to microplastics: the impact on the marine ecosystem and beyond
When the plastic reaches the marine environment, it does not degrade completely, but fragments into ever smaller debris, called microplastics. The European Chemical Agency (ECHA) defines microplastics as “material composed of solid particles containing poly-mers, to which additives or other substances can be added”.
The family of microplastics includes synthetic-based particles such as polypropylene (PP), polystyrene (PS), polyamides (PA), polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyacrylonitrile (PAN), polymethylacrylate (PMA), elastomers and rubber silicone with particles ranging from 1 to 5 µm. In addition to particles, fibers with a length between 3 and 15 µm and a length-to-diameter ratio that must be greater than 3 also fall within the def-inition of microplastics.
Microplastics are ubiquitous elements that are dispersed in the air, soil and water. Here, once ingested by the biota they accumulate in organs and tissues, causing strong inflam-matory states, as well as entering the food chain of humans who eat fish. And the effects this step has on our health are still unknown. Furthermore, microplastics can become carri-ers of toxic chemicals, such as persistent organic micropollutants (POPs).
Microplastics have a devastating impact on the marine ecosystem, but also on lakes and rivers
Micro-FTIR image of fibrous microplastics collected on a silicon filter
Synthetic fibers: the difficulty of measuring particles
A study by the European Environment Agency, published at the end of January 2021, shows that in Europe the global consumption of synthetic fibers has gone from a few thousand tons in 1940 to more than 60 million tons in 2018 and continues to increase. The use of synthetic fibers in the fashion industry has grown enormously, reaching 61% of global fiber demand. The most common synthetic fibers are polyester, polyamide and polypropylene 3. It is estimated that washing synthetic clothing alone releases about 35% of all microplastics into water. The release also takes place during some processing steps or with the recycling of the garment and, finally, when this ends up in landfills as the fibers, due to their elongated shape and average size, are not totally retained by the purification plants. If we give an example, in a city of 100,000 people, an optimal purification plant, which retains 94.8% of microplastics, still produces 0.35 m3 of sewage per person, therefore 1.02 kg of fibers per day.
The standard method developed by AQUAFIL and STIIMA
According to these premises, Aquafil, the European leader and one of the first players worldwide in the synthetic fibers sector, has decided to invest in a multi-year research project by developing a standard method to identify and quantify the fibrous microplastics released by the textile industry. In order to better develop the project, Aquafil has been collaborating for three years, also funding a scholarship for young researchers, with the Institute of Intelligent Industrial Systems and Technologies for Advanced Manufacturing of the CNR, with particular reference to the colleagues at the headquarters of Biella which is dedicated to research and innovation activities on manufacturing technologies and materials in the textile industry.
In 2019, thanks to this collaboration, a first draft was presented with the proposal of a standard method to the Italian Standardization Body (UNI) within the WG 046. The Body decided to support and present the project to the Commission International ISO (international organization for standardization) and CEN (European Committee for Standardization). The standard protocol is necessary to obtain useful indicators also for assessing the possible risk to which humans are exposed. Supported by UNI, the project has already received the positive opinion of the textile commissions.
The proposed method provides for a pre-screening of the samples for the evaluation of the need for a pre-treatment (oxidative and / or acidic) for the purification of the synthetic material from the protein or saline organic material. Subsequently, the sample is adequately filtered to pass to the spectroscopic analysis with Micro-FTIR of the fibrous microplastics collected on the filter. The results are processed through an image analysis that allows the correct identification both from the chemical point of view (determination of the type of polymer) and physical as the count and dimensions (diameter and length). The acquisition of physical parameters is very significant for assessing the ecotoxicological impact of the same in the biota and then in the food chain.
The assessment of the ecotoxicological impact of microplastics was included as an appendix within the method and was developed by Dr A. Binelli and Dr. S. Magni of the Department of Biosciences of the State University of Milan.
Mapping (counting and chemical identification) of fibrous microplastics collected on silicon filter.
Parallel initiatives by ISO and CEN
Currently, as requested by the ISO and CEN commissions, the validation of the method with the Round Robin Test (RRT) is being organized, involving public and private, national and international laboratories, which have µ-FTIR or µ-Raman analytical instrumentation.
The standardization of the method is expected to be completed by the 2nd / 3rd quarter of 2022 in line with the directives of the European Commission (State of the Union 2021, Letter of Intent), which confirmed its intention to present a proposal legislation aimed at reducing the release of microplastics into the environment and limiting the addition of microplastics in products.
Mossotti, R.; Dalla Fontana, G.; Anceschi, A.; Gasparin, E.; Battistini, T. Preparation and Analysis of Standards Containing Microfilaments/Microplastic with Fibre Shape. Chemosphere 2021, 270, 129410.
Dalla Fontana, G., Mossotti, R., Montarsolo, A., 2020. Assessment of microplastics release from polyester fabrics: the impact of different washing conditions. Environ. Pollut. 264, 113960. https://doi.org/10.1016/j.envpol.2020.113960.
Dalla Fontana, G.; Mossotti, R.; Montarsolo, A. Influence of Sewing on Microplastic Release from Textiles During Washing. Water, Air, Soil Pollut. 2021, 232 (2), 50.