Chemical pollution and ecotoxicological effects of high-density polyethylene microplastics in Mytilus galloprovincialis from two Italian lagoon ecosystems

Transitional water ecosystems have low water exchanges and can trap chemicals and microplastics (MPs). In this study, MPs, trace elements, polycyclic aromatic hydrocarbon-PHAs levels and the oxidative stress response were assessed in Mytilus galloprovincialis from two Italian lagoon ecosystems (Orbetello and Varano). In addition, the ecotoxicological effects induced by the exposure of M. galloprovincialis to high-density polyethylene-HDPE MPs were also determined. Levels of trace elements were almost always comparable among the sites, whereas MPs were found only in mussels from Orbetello. PAHs were always under the limit of quantification. Glutathione peroxidase and malondialdehyde levels were significantly higher in mussels from Varano. As regard the exposure test, it was found a significant effect of treatment, site and their interaction on mortality and biochemical bio-markers in both fed and unfed mussels. However, principal component analysis suggests similar effects of both color and nourishment condition on biochemical biomarkers. These findings warrant further investigation.

Automated summary

This study assessed microplastics, trace elements, polycyclic aromatic hydrocarbon (PHA) levels, and the oxidative stress response in Mytilus galloprovincialis from two Italian lagoon ecosystems. They also determined the ecotoxicological effects of high-density polyethylene (HDPE) microplastics on the mussels. Trace element levels were comparable among sites, while microplastics were only found in mussels from one site. Polycyclic aromatic hydrocarbon levels were always below the limit of quantification. The mussels from a different site had higher levels of oxidative stress biomarkers. The exposure test showed significant effects on mortality and biochemical biomarkers, and similar effects were observed based on color and nourishment conditions.