A comparison of the toxicity of biodegradable fibres to the globally abundant estuarine copepod, Acartia tonsa

Microplastics in the marine environment have emerged as a complex and concerning issue in recent years. Microfibres are the most abundant form of microplastic found in the marine environment and are bioavailable to a wide range of marine animals, including zooplankton, where microplastics overlap in size with their prey. Microfibres are produced from textiles and clothing through wear or washing, and cellulose acetate fibres are produced during the breakdown of cigarette butts. Bio-based, biodegradable polymers are widely considered to be a viable alternative to conventional fossil-based plastic, but little is known about their ecotoxicological risk. This study sought to explore and compare the toxicity of microfibres (sized 5—63 µm) from a) biobased, biodegradable textiles and fossil-based plastic textiles in both their raw, undyed and dyed forms and b) cellulose acetate fibres from unsmoked, artificially smoked and smoked, littered cigarette butts on the globally distributed copepod, Acartia tonsa. Adapting existing ISO toxicity standards, dose response experiments were conducted using F0 adults at concentrations ranging 0—120 mg L-1, combined with partial life cycle assessments of female F0 and resulting F1 generations, at a concentration of 0.1 mg L-1. Here we present the findings of the study, where a) differences in toxicity of dyed forms of textiles compared to undyed forms were observed, as well as some differences evident between materials and b) cellulose acetate fibres from smoked cigarette butts were more toxic than littered or unsmoked butts. The results from this study will be incorporated into environmental risk assessments and guide the future development and use of biodegradable plastics. Also see: https://micro2024.sciencesconf.org/559641/document