Microplastics are very small pieces of synthetic material with dimensions ranging from 0.1 µm to 5 mm (according to the European Chemical Agency and the European Food Safety Agency). Because of this wide definition, the category contains a great number of particles of different nature and origin.
Their presence in the seas, and not only, has become a widely discussed problem triggering enormous interest of the international media. Microplastics have been found not only in the marine habitats but also in the animals (in the digestive system of fish and shellfish) and in our food (fish, marine salt, beer, etc.). The discovery of the particles, ever-present at this point, has led to important questions on their polluting potential with numerous research and studies all over the world that aim at a thorough evaluation of their effects on our environment. Just like plastic bottles, microplastics accumulate in big quantities, they do not deteriorate but last for a long time within the environment leading to detrimental consequences for our ecosystems and human health. The control and measurement of the quantities of these materials are therefore crucial to protect the environment, the seas and our health.
Microfibres, microplastics in textiles
Textile sector has been included among the main causes of the presence of microplastics in the environment: today, more than 45% of textile fibers in commerce are of synthetic origin (polyester, polypropylene, nylon, etc.) and they can release materials either during the production and finishing stages or due to the usual garment maintenance processes (mainly washing and drying). These fragments of synthetic fibers are included in the category of microfibers (microplastics with the length/diameter ratio higher than 3) that are released
into the environment (air or water) and that contribute to the pollution by microplastics.
The release of microplastics by textile products is mainly to be assigned to the washing stages where microplastics are dispersed into the water of a washing machine. A crucial part of the examination of microplastics is therefore connected to the estimate of the release during the washing cycles in the washing machine.
While waiting for some more specific methods, it is advisable to pay attention to the data published online, in magazines or brochures as the change in the washing conditions and methods of calculation can make the figures vary significantly. They can underestimate or overrate the results, either to the advantage or disadvantage of some products.
The quantification of microfibres
In order to obtain reliable data, the scientific community has focused on measurement systems of the quantity of microplastics in various fields including textile and apparel sector.
The first approach is that of carrying out comparative studies based on the analysis and on the laboratory-scale processes using methods and equipment for color solidity testing and for the simulation of the garment maintenance processes. The methods aim at recreating the conditions of textiles use and washing examined on a small scale which makes the sampling and measurement stages easier. Nevertheless, even if these methods are based on international regulations, they do not always reproduce the real conditions of use accurately. On the other hand, they allow to analyze specific conditions, factors and characteristics of textiles that could influence the release and express a comparative summary evaluation of different samples.
What has been proved is that, e.g. the release is conditioned by the title, section and yarn texturizing, by the type of loom and weaving but also by the type of detergent as the powder one is more abrasive.
The use of the tests results to evaluate the general release on the European level is problematic as none of the tests managed to recreate what exactly happens when a typical batch of garments is washed in “real” circumstances.
For this reason, other analysis methods are being developed, based on the use of domestic or lab washing machines, yet always in conditions when the load and washing are as authentic as possible if compared to the usual use.
The sampling and quantification of microfibers in the domestic and industrial washing machines drain water are yet quite hard and complex. They present numerous critical issues among which there are water volumes that undergo examination and the time of the analysis. The quantification of the particles can mainly follow two roads: gravimetric evaluation (weight) of the collected material or the count of the samples, collected from the waste water, under the microscope. The first one provides an indication on the total quantity of the fibers released by the sample during one or more washing cycles, without any indication on the type nor on the nature of the collected fibers. The microscope analysis, on the contrary, allows for the quality identification of the collected fibers in order to confirm their origin and the chemical nature. What is more, it allows to thoroughly analyze the fibers (type, dimensions, composition, the percentage of mixed fabrics) and possibly, the estimate (proportional) of the total quantity if compared to other components or contaminants.
Recently, numerous analysis methods and new tools have entered the design and testing stages so that it will be possible to obtain realistic and reliable evaluation of the microplastics released by textile products. Many companies have already started focusing on new alternatives and remedies to the release of microplastics due to textiles washing. Only by getting to know and analyzing the problem in depth as well as the impact it has, will we be able to evaluate the right solutions to protect the people’s health and our planet.
by Elena Conti – Centrocot Spa Area Ricerca & Innovazione Multisettoriale
(Multi-Sector Research & Innovation Area)
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