Effects of microplastics from cigarette filters on two aquatic species and in vitro human lung cells

Cigarette filters are a major source of microplastics (MPs) that end up in the environment and human may also be exposed. An estimated 4.5 trillion cigarette filters per year pollute oceans, rivers, sidewalks, parks, soils and beaches. So far, the effects of these MPs on the environment and human have not been extensively studied. In this study, we investigated the toxicity of six different MPs cryomilled from used (smoked) cigarette filters (polymer parts) and subsequently artificially aged (Q-SUN Xe-3 Xenon arc chamber, full-spectrum sunlight, noon summer sunlight for 24 h a day, 1000 h). Tested MPs were: pristine and UV-weathered cellulose acetate filters from conventional cigarettes, pristine and UV-weathered cellulose acetate filters from heated tobacco devices, and pristine and UV-weathered poly(lactic acid) polymer filters from heated tobacco devices. Ecotoxicity was investigated with water fleas (Daphnia magna, 48 h immobilization test) and common duckweed (Lemna minor, 168 h growth inhibition test). In vitro toxicity was assessed with A549 human lung cells. No effects on water fleas and duckweed were found up to 100 mg/L. Of all the materials tested, only UV-weathered filters from conventional cigarettes caused statistically significant cytotoxicity to A549 human lung cells at 100 mg/L. In conclusion, the results showed that different cigarette filters may not have immediate ecotoxicological effects, but their long-term effects are still unknown. Given that they may persist in the environment for a long time, their long-term effects should be further investigated. This work was supported by the Slovenian Research and Innovation Agency (ARIS) grants J1-50014, P1-0207 and P2-0424. Also see: https://micro2024.sciencesconf.org/559439/document