Environmental toxicity of organic UV filters at predicted no-effect concentrations in soil organism, Eisenia fetida

Abstract

Organic UV filters (OUVFs) are categorized as emerging environmental contaminants (EECs) owing to their extensive use and widespread occurrence. Recent findings indicate their potential adverse effects on biota inhabiting different ecological niches. The present work was carried out to investigate the environmental toxicity of OUVFs at predicted no-effect concentrations (PNEC) derived from lethal concentrations and ascertain the accuracy of the application factor to derive PNEC in soil ecotoxicology. Results of acute toxicity revealed that benzophenone-type OUVFs are found to be significantly toxic [Benzophenone (BP)>Oxybenzone (BP-3)>Octocrylene (OC)=4-Methylbenzylidene camphor (4-MBC)] than camphor and cinnamic acid derivatives during acute exposures. Based on the LC50, PNEC has been derived by applying 1000 as the soil application factor. Using the derived PNEC, the RQ for the selected OUVFs was found to be OC>4-MBC>BP-3>BP. The short and long-term exposure at PNEC (BP: 0.17 mg/Kg; BP-3: 0.36 mg/Kg; OC: 2 mg/Kg); 4-MBC: 2 mg/Kg) showed no significant changes (p>0.05) in earthworm mortality, biomass, and reproduction in terms of hatchling and cocoon production and cocoon weight during the single and combined exposures of PNEC. Nonetheless, at the cellular level, single exposure has negligible effects on oxidative stress and neurotoxicity markers to BP and OC OUVFs and invariably reduced activity on ROS, showing earthworms adaptation to OUVFs toxicity at PNECs, whereas combined exposure resulted in antagonistic effects. Based on the present experimental investigation, the null hypothesis is rejected, and the accuracy of the application factor to derive PNEC in soil ecotoxicology is validated.