Organic chemistry

Ceriodaphnia dubia

Rotifer

Genotoxicity

Daphnia magna

Biology

Zoology

Environmental chemistry

Acute toxicity

Brachionus calyciflorus

Chemistry

Ecology

Cladocera

Brachionus

Toxicology

Chronic toxicity

Toxicity

Crustacean

Chemosphere

The ongoing COVID-19 pandemic is leading to an increase of the global production of plastics since the use of personal protective equipment (PPEs, i.e. gloves, gowns, masks, packaging items), has become mandatory to prevent the spread of the virus. Plastic breaks down into micro/nano particles due to physical or chemical or biological actions into environment. Due to small dimensions, ubiquitous and persistent nature, the plastic particles represent a significant threat to ecosystems and can entry into food chains. Among the plastic polymers used for PPEs, polystyrene is less studied regarding its eco-geno-toxicity. This study aims to investigate acute, chronic and subchronic effects of the microplastic polystyrene beads (PS-MP, size 1.0 μm) on three freshwater species, the alga Raphidocelis subcapitata, the rotifer Brachionus calyciflorus, the crustacean Ceriodaphnia dubia and the benthic ostracod Heterocypris incongruens. Furthermore, the potential genotoxicity and the ROS production due to the PS-MP were also determined in C. dubia. Results revealed that the acute effects occurred at concentrations of PS-MP in the order of dozens of mg/L in B. calyciflorus and C. dubia and hundreds of mg/L in H. incongruens. Regarding long-term toxicity, increasing chronic effects with EC50s in the order of units (C. dubia), hundreds (B. calyciflorus) and thousands (R. subcapitata) of μg/L were observed. Both for acute and chronic/sub chronic toxicity, daphnids were more sensitive to polystyrene than ostracods. Moreover, when C. dubia neonates were exposed to the PS-MP, alterations in genetic material as well as the production of ROS occurred, starting from concentrations in the order of units of μg/L, probably due to inflammatory responses. At last, the risk quotient (RQ) as a measure of risk posed by PS-MPs in freshwater environment, was calculated obtaining a value of 7.2, higher than the threshold value of 1.

Toxic impact of polystyrene microplastic particles in freshwater organisms