Effect of microfibers induced toxicity in marine sedentary polychaete Hydroides elegans: Insight from embryogenesis axis.

Presence of surgical face masks in the environment are more than ever before after the COVID-19 pandemic, and it poses a newer threat to aquatic habitats around the world due to microfibers (MFs) and other contaminants that get discharged when these masks deteriorate. The mechanism behind the developmental toxicity of MFs, especially released from surgical masks, on the early life stages of aquatic organisms are not well understood. Toxicity test were developed to examine the effects of MFs released from surgical facemask upon deterioration using the early gametes and early life stages of marine sedentary polychaete Hydroides elegans. For MFs release, cut pieces of face masks were allowed to degrade in seawater for different time points (1 day, 30 days and 120 days) after which the fibers were obtained for further toxicity studies. The gametes of H. elegans were exposed to the MFs (length < 20 μm) separately for 20 min at a concentration of 50 MFs/ml before fertilization. In addition, we also analyzed the experimental samples for heavy metals and organic substances released from face masks. Our findings demonstrated that gametes exposed to MFs affected the percentage of successful development, considerably slowed down the mitotic cell division and significantly postponed the time of larval hatching and also produced an adverse effect during embryogenesis. When the sperm were exposed fertilization rate was decreased drastically, whereas when the eggs were exposed to MFs fertilization was not inhibited but a delay in early embryonic development observed. In addition the release of heavy metals and other volatile organics from the degrading face masks could also contribute to overall toxicity of these materials in environment. Our study thus shows that inappropriately discarded face masks and MFs and other pollutants released from such face masks could pose long-term hazard to coastal ecosystems.