CSIC confirms the impact of face mask degradation on zebrafish, a model organism.
- Details of the study are published in the Journal of Hazardous Materials.
- The Immunology and Genomics group at the IIM, in collaboration with the University of Cádiz, has observed that surgical masks that are fragmented and degraded by the action of ultraviolet radiation affect genes related to zebrafish reproduction. Up to 40 genes related to reproduction were identified, as well as other biological processes related to the immune response and metabolic processes.
- Zebrafish is a model species for studying all kinds of biological responses, including human ones. Therefore, these results suggest that these degradation products can condition the functioning of the populations of different species, including humans, and, consequently, affect the ecosystem.
- The study also addresses the behaviour of surgical masks in fresh water, as well as the compounds they release in an initial and advanced stage of degradation. The results indicate that they can leave a chemical footprint in aquatic ecosystems through the release of degradation by-products.
- As a result of COVID-19, the Immunology and Genomics group is developing part of its research on issues related to the pandemic. Its results include the sequencing and monitoring of the SARS-CoV-2 virus and its variants in wastewater samples, as well as its relationship with the microbiome of patients with the disease.
Santiago de Compostela, February 7, 2022. The Spanish Research Council (CSIC), through the Institute of Marine Research (IIM) and in collaboration with the University of Cádiz (UCA), publishes the results in the Journal of Hazardous Materials of a study on surgical masks as a source of pollution in aquatic ecosystems and in the organisms that inhabit them, specifically, in the zebrafish (Danio rerio), a model organism.
The study has made it possible to identify different processes in zebrafish that are significantly affected by the degradation products of the masks, among which the reproduction process stands out.
“Personal protection equipment, such as masks, is essential to stop and contain the COVID-19 pandemic, which is why its consumption has increased exponentially with the generation of a high volume of waste, on many occasions poorly managed, which results in them reaching both terrestrial and aquatic environments”, researchers at the Immunology and Genomics group of the IIM explain.
In this context, the group designed a study with a transcriptomic approach using RNA-Seq analysis that focuses on the effects of surgical masks on aquatic ecosystems and organisms that inhabit them.
“Surgical masks are for daily use and are made up, fundamentally, of a microfiber fabric of different plastic polymers, organic and inorganic additives. In the environment, where they degrade, they can be a source of microfibers and leave their corresponding chemical footprint in aquatic systems. For this reason, attention must be paid to this issue”, indicates Marta Sendra.
The study was carried out with commercial masks made in China purchased at a local pharmacy and with 240 specimens of zebrafish larvae reared under established protocols in the IIM laboratories. It had two big goals.
The first, to characterize the composition of organic and inorganic compounds of the masks and investigate their behaviour in fresh water, as well as the compounds they release in an initial degradation stage and in an advanced stage after a week.
“For the initial degradation, 2 mm square pieces were used and for the advanced one, these pieces were ground in order to achieve greater fragmentation. These fragments were kept independently in fresh water for a week with a daily exposure to UVC light for eight hours for their degradation”, explains Marta Sendra, who adds that “the analyses of the water revealed that there was a small release of iron, copper and zinc and another of three organic compounds resulting from the degradation of the mask”.
The second objective, taking the zebrafish, a model organism, as the object of study, was to analyse the effects of mask degradation on marine species. They did so through exposure experiments, studying the genes expressed in animals exposed to degradation products.
“The zebrafish specimens were exposed for ten days to control, treatment with pieces of mask and water from their initial degradation; treatment with pieces of mask and water from its advanced degradation and only water from advanced degradation”, explains Antonio Figueras.
The results revealed that the mask treatments, either with fragments of different sizes or with just water, affected zebrafish genes related to their reproduction. The most pronounced effects were observed, first, in those exposed to highly degraded pieces and water from highly degraded masks; secondly, in those exposed to initially degraded pieces with water from slightly degraded masks and finally only with water that had been in contact with entire masks.
“If a treatment with highly degraded masks is applied to them, 40 zebrafish genes related to three phases of their reproduction are affected: gamete development, sperm-ovum recognition and fertilization,” Marta Sendra points out.
“The results suggest that the biological processes affected by surgical mask fragments could not only occur at the individual level but also at the population level through reproductive and fertility problems. However, these effects will depend on the degree of degradation of the surgical masks”, they conclude from the CSIC.
Reference:
Marta Sendra, Patricia Pereiro, María Pilar Yeste, Beatriz Novoa, Antonio Figueras (2022). Surgical face masks as a source of emergent pollutants in aquatic systems: Analysis of their degradation product effects in Danio rerio through RNA-Seq., Journal of Hazardous Materials, Volume 428,