SANTA CRUZ DE TENERIFE, December 14 (EUROPA PRESS) –
The research project ‘Microplastics as indicators of pollution in isolated high mountain systems: Teide National Park’ (MICROTEI), funded entirely by the Canarina Foundation with 30,000 euros, ended this Thursday after a year and four months of work with a day of presentation of final results held in the Chemistry Section of the Faculty of Sciences of the University of La Laguna in which the presence of microplastics in the Teide National Park has been confirmed.
The day was inaugurated by Antonio Aparicio, vice-rector for Research and Transfer of the University of La Laguna; Anne Striewe, general director of the Canarina Foundation; Pedro Millán, insular director of the Natural Environment of the Cabildo of Tenerife and Javier Hernández Borges, principal investigator of the project and coordinator of the Applied Analytical Chemistry research group (AChem) of the University of La Laguna, who highlighted the importance of this type of studies to know more accurately the origin, transportation and final destination of microplastics and recognized the foundation’s commitment to this type of work.
The objective of the project has been the determination of microparticles of anthropic origin such as microplastics (size less than 5 millimeters) in soil and rabbit and mouflon excrement in the Teide National Park.
This presence of microplastics has barely been studied and is of special relevance to understand the degree of impact of this type of ecosystems by these relatively new contaminants, states a note from the ULL.
In particular, its determination in feces of the only two species of herbivorous mammals present in the National Park allows evaluating the entry of these particles into the terrestrial food chains, and can be considered as another indicator of contamination.
A study of this type is the first time it has been carried out in a Spanish National Park.
BEGINNINGS OF THE PROJECT
The first stage consisted of carrying out an ambitious and arduous two-month sampling, in which 14 expeditions were carried out that concluded with the taking of 155 samples (78 of soil, 64 of rabbit excrement and 13 of excrement of mouflon).
Sampling was carried out systematically to cover practically the entire surface of the National Park (189.9 square kilometers), involving 89 hours of field work and walking a total accumulated distance of 166 kilometers.
Once in the laboratory, different conditions were studied and applied to carry out the treatment of the samples, a stage that must be carried out prior to the identification and characterization of microplastics.
Thus, once the methodologies had been evaluated and optimized, each soil sample was sequentially subjected to oxidation with concentrated hydrogen peroxide, to four consecutive separations by density of the microparticles using a saturated solution of sodium chloride and, finally, to a vacuum filtration.
For their part, the stool samples were carefully disaggregated under a stereoscopic magnifying glass with the help of fine punches.
Due to the large number of soil samples collected, the laborious nature of the sample treatment stage and the fact that each of them is analyzed in triplicate, to date only 19 of them have been able to complete the analysis.
This preliminary work has allowed us to determine that, at the moment, the average concentration of these particles is 228 +- 46 items per kilogram of dry soil, mainly fibers (96%), although other particles such as fragments (rigid plastics) have also been found. with irregular edges), small films or films and tangles.
The microparticles found have been mostly colorless and less than 1 millimeter in size, so, in general, they are not visible to the human eye.
The chemical composition of the microplastics found has been very diverse, with polymethyl methacrylate, ethyl vinyl acetate (EVA rubber), polystyrene and polyester as the most found synthetic polymers, although 69% of the microparticles are cellulosic in nature, both natural (which cannot be considered as microplastics) as semi-synthetic.
They are particles that come mostly from the textile industry and that may have reached the soil through the air due to dry or wet deposition (rain or snow).
In fact, in previous work by the AChem group, microplastics had already been found in snow in the Teide National Park.
Regarding fecal matter, a total of 616 excrements were analyzed (512 rabbit and 104 mouflon), which constitutes a number of samples notably higher than those studied by other research groups in similar works with different wild terrestrial mammals from other countries. parts of the world.
Thus, it has been concluded that 96% of the excrement analyzed was free of microplastics, although, due to its small mass, it was also determined that the feces of both animals present an average of about 790 anthropogenic particles per kilo of dry excrement. which shows that these herbivores are ingesting this type of particles.
Again, the most recurrent were fibers (95%), although films and fragments also appeared.
The study also revealed that the microparticles were mostly cellulosic in nature, although polypropylene and EVA rubber particles were also found.
REPERCUSSION
Over the last year, these advances have been gradually made public through different means.
On the one hand, various communications have been presented at conferences and we have also participated in an informative workshop for students between the ages of 10 and 12 held in La Plaza del Tranvía de La Cuesta in June 2023.
Likewise, a final project has been carried out in the Master’s Degree in Terrestrial Biodiversity and Conservation on Islands at the University of La Laguna, to which must be added the publication of the results in two scientific articles.
Due to the success of the project and the importance of the results obtained, its continuation is currently being processed to complete the analysis of microplastics in the soils already collected from the National Park and, in addition, take new samples, both of soil and groundwater, and even analyze the air inside the park’s volcanic tubes, to achieve a better understanding of the phenomena involved in the dispersion of plastic pollution and determine its extent in a remote, protected terrestrial environment of high ecological value such as the Park. National of El Teide.
