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In this paper, we investigated the ecotoxicity to of second and third generation bioplastics toward the freshwater zooplankton Daphnia magna.
- In acute toxicity tests (48 h), survival was impacted at high concentrations (g.L-1 range), within the range of salinity-induced toxicity.
- Macroalgae-derived bioplastic induced hormetic responses under chronic exposure (21 d). Most biological traits were enhanced from 0.06 to 0.25 g.L-1 (reproduction rate, body length, width, apical spine, protein concentration), while most of these traits returned to controls level at 0.5 g.L-1.
- Phenol-oxidase activity, indicative of immune function, was enhanced only at the lowest concentration (0.06 g.L-1). We hypothesise these suggested health benefits were due to assimilation of carbon derived from the macroalgae-based bioplastic as food.
- Polymer identity was confirmed by infra-red spectroscopy. Chemical analysis of each bioplastic revealed low metal abundance whilst non target exploration of organic compounds revealed trace amounts of phthalates and flame retardants.
- The macroalgae-bioplastic disintegrated completely in compost and biodegraded up to 86 % in aqueous medium.
- All bioplastics acidified the test medium.
In conclusion, the tested bioplastics were classified as environmentally safe. Nonetheless, a reasonable end-of-life management of these safer-by-design materials is advised to ensure the absence of harmful effects at high concentrations, depending on the receiving environment.
Read the full paper here.
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