Cellular disturbance and thermal stress response in mussels exposed to synthetic and natural microfibers

Abstract

Textile microfibers (MFs) have natural (e.g. cotton, wool and silk) or synthetic origin (e.g. polyester and polyamide), and are increasingly documented in the marine environment. Knowledge on their biological effects in marine organisms is still limited, and virtually unexplored is their capability to modulate the responsiveness toward other stressors, including those of emerging relevance under global changes scenario. With such background, the aims of this study were to i) determine the ingestion and biological effects of MFs, discriminating between synthetic and natural ones, and ii) elucidate the possibility that MFs alter the responsiveness toward additional stressors occurring at a later stage, after exposure. Adult mussels Mytilus galloprovincialis were exposed for 14 days to a high but still environmentally realistic concentration of 50 MFs L-1 of either polyester (618 ± 367 µm length, 13 ± 1 µm diameter), polyamide (566 ± 500 µm length, 11 ± 1 µm in diameter) or cotton (412 ± 342 µm length, 16 ± 4 µm diameter). After the exposure, mussels were left for 7 days to recover at control temperature (23°C) or exposed to a heatwave condition (27°C). At the end of each phase (exposure – recovery – heat stress), MFs ingestion-elimination was evaluated, along with a wide panel of biological responses, including neuro-immune and antioxidant systems alterations, lipid metabolism and onset of cellular damages. Results were elaborated through a Weight of Evidence approach to provide synthetic hazard indices based on both the magnitude and toxicological relevance of observed variations. Beside limited differences in retention and elimination of MFs, biological analyses highlighted disturbance of the immune system and demand of protection toward oxidative insult, particularly evident in mussels exposed to synthetic-MFs. Carry-over effects were observed after 7 days of recovery: organisms that had been previously exposed to MFs showed a higher susceptibility of the neuroendocrine-immune system and lipid metabolism to thermal stress compared to un-exposed mussels. Overall, this study provided evidence of direct cellular effects of MFs, emphasizing differences between synthetic and natural ones, and highlighted their capability to modulate organisms’ susceptibility toward additional stressors, as those predicted for future changes in marine ecosystems.

Environmental safety of nanocellulose: an acute in vivo study with marine mussels Mytilus galloprovincialis

“…47 In farmed mussels from the Mediterranean Sea M. galloprovincialis, synthetic and natural textile microfibers (an average of 14.5720 microfibres per individual) have been documented with cotton and wool as the majority (54% and 985.14 μm in length), raising concerns owing to recent reports on neurotoxicity, oxidative stress and metabolic and developmental disorders. 48,49 To date, no information is available on the effects of nanoscale natural fibers although fragmentation below 100 nm could naturally occur and is more likely in areas receiving higher amounts, such as along marine coasts. To fill such a knowledge gap, herein, we investigate the uptake and biological effects of NC fibers in the marine mussel M. galloprovincialis through an acute in vivo exposure (96 h uptake; 48 h effects) using synthesized CNF and TOCNF in two concentrations: a) 1 μg L −1 in the range of Predicted Environmental Concentrations (PEC, 0.23-2.37 μg L −1 in 2025 by Stoudmann et al 24 ) and b) 1 mg L…”

“…In farmed mussels from the Mediterranean Sea M. galloprovincialis , synthetic and natural textile microfibers (an average of 14.5720 microfibres per individual) have been documented with cotton and wool as the majority (54% and 985.14 μm in length), raising concerns owing to recent reports on neurotoxicity, oxidative stress and metabolic and developmental disorders. 48,49…”

The tolerance of a keystone ecosystem engineer to extreme heat stress is hampered by microplastic leachates

“…[52][53][54][55][56], including plastics, e.g. [31,[57][58][59], have previously been documented in mussels under conditions of immersion. This present work, however, provides the first evidence of an enhanced thermal mortality through an exposure to microplastic leachates.…”

Impact of Fibrous Microplastic Pollution on Commercial Seafood and Consumer Health: A Review

“…Microfiber ingestion in oysters and mussels may negatively affect shellfishes' reproductive output [53]. Mytilus galloprovincialis exposed to synthetic and natural microfibers resulted in different magnitudes of biological disturbance, depending on the nature of the microfiber [54]. Watts et al [55] reported reductions in food consumption and in energy available for growth of the shore crab Carcinus maenas due to microfiber exposure.…”