engleski

Toxic effects of microplastics on freshwater microalgae Pseudokirchneriella subcapitata and crustacean Daphnia magna

Microplastic pollution has become a growing problem worldwide. Microplastic (MP) in the aquatic environment enter the food chain and cause negative impacts on human health and the ecosystem. MP serve as a vector for various substances present in water, including emerging and priority pollutants such as pharmaceutics and pesticides. The adverse effect of MP in water is therefore influenced by factors affecting adsorption capacity ; particle size, specific surface area, aging degree, crystallinity, and polarity of MP, and the properties of organic pollutants. In this study, we investigated the interactions of polyethylene terephthalate (PET) MP with pharmaceutics and pesticides in water. The aim was to establish the correlation between the properties of MP and the adsorption capacity for the studied pollutants, and to elucidate the resulting toxic effect. For that purpose, we tested the adsorption of pharmaceutic diclofenac and pesticide atrazine on PET MP of different particle sizes and aging degree. PET was inspected for morphological changes, induced by accelerated aging under UV irradiation, using Fourier Transformation Infrared Spectroscopy and Differential Scanning Spectroscopy techniques. In adsorption tests, using pristine and aged PET MP, the concentration of pollutants in aqueous phase was monitored by HPLC analysis. Aquatic toxicity of MP was assessed by exposing freshwater organisms to the aqueous dispersion of pristine and aged MP, without and with adsorbed pollutants. Acute toxicity bioassays were performed with the microalgae Pseudokirchneriella subcapitata (Selenastrum capricornutum) and the crustacean Daphnia magna according to standard procedures (ISO). It was shown that the toxicity of MP increases with the aging degree which is correlated with enhanced adsorption capacity owing to morphological changes and the formation of surface functional groups during accelerated aging, as confirmed by the observed changes in carbonyl index. Complex samples indicated additive toxicity effects in the case of both organisms, in comparison with the individual components, indicating the complexity of the emerging problem of MPs in the aquatic environment.

Microplastics, Pharmaceuticals, Adsorption, Toxicity

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