Single and mixture toxicity evaluation of three phenolic compounds to the terrestrial ecosystem

Endocrine-disrupting chemicals (EDCs) are primarily studied regarding endocrine-mediated effects in mammals and fish. However, EDCs can cause toxicity by mechanisms outside the endocrine system, and, as they are released continuously into soils, they may pose risks to terrestrial organisms. In this work, the plant Allium cepa and the earthworm Eisenia foetida were used as test systems to evaluate the toxicity and cyto-/geno-toxicity of three environmental phenols known as EDCs (Bisphenol A – BPA, Octylphenol – OP, Nonylphenol – NP). The tested phenols were evaluated in environmentally relevant concentrations (μg/L) and in single forms and mixture. BPA, OP, and NP did not inhibit the seed germination and root development in A. cepa in their single forms and mixture. However, all single forms of the tested phenols caused cellular and DNA damages in A. cepa, and although these effects persist in the mixtures, the effects were verified at lower levels. These phenols caused acute toxicity to E. foetida after 48 h of exposure and at both conditions evaluated (single forms and mixture); however, unlike A. cepa, in earthworms, mixtures and single forms presented the same level of effects, indicating that interspecies physiological different might influence the mixture toxicity. In summary, our results suggest that BPA, OP, and NP are toxicants to earthworm and cyto-/geno-toxicants to monocotyledonous plants at low concentrations. However, interaction among these phenols reduces the magnitude of their individual effects (antagonistic effect) in the plant test system. Therefore, this study draws attention to the need to raise knowledge about the ecotoxicity of phenolic compounds to help predict their ecological risks and protect non-target terrestrial species. [Display omitted] •Phenolic EDCs are frequently found in soils and may affect terrestrial organisms.•BPA, OP and NP induced lethal effects in earthworms at low concentrations (μg/L).•BPA, OP and NP is cyto- and geno-toxicants to plant system at low concentrations.•Their individual toxicity and cyto-/geno-toxicity are higher than their mixtures.•Interaction among BPA, OP and NP had an inhibitory effect in their single toxicity. In low concentrations, BPA, OP and NP caused cyto-/geno-toxic and lethal effects to plants and earthworms, respectively. Interaction among these phenols reduces the magnitude of their individual effects (antagonistic effect) in the plant test systems.