Cadmium (Cd) and aniline frequently co-occur in industrial settings but have rarely been addressed as composite toxicants in terms of the overall toxicity despite extensive knowledge of the environmental impact of each individual pollutant. In this study, we attempt to assess the relation of individual and combined toxic effects of Cd and aniline using a bacterial consortium cultured from soils as a model system. Results showed that the consortial bacteria exhibited drastically stronger tolerance to stand-alone Cd and aniline in comparison to literature data acquired from single species studies. When occurring simultaneously, the joint toxicity displayed a concentration-dependent behavior that wasn't anticipated based on individual chemical tests. Specifically, additive effects manifested with Cd and aniline at their IC₁₀s, but changed to synergistic when the concentrations increased to IC₂₀, and finally transitioned into antagonistic at IC₃₀s and beyond. In addition, co-occurring aniline appeared to have retarded the cellular accumulation of Cd while increasing the enzymatic activities of superoxide dismutase and catalase relative to that in Cd-alone treatments. Finally, the bacterial community experienced distinct compositional changes under solo and combined toxicities with several genera exhibiting inconsistent behavior between treatments of single and composite toxicants. Findings from this study highlight the complexity of bacterial response to composite pollutions and point to the need for more comprehensive references in risk and toxicology assessment at multi-chemical contamination sites.

镉 (Cd) 和苯胺经常在工业环境中同时出现，但就整体毒性而言，很少被视为复合毒物，尽管人们对每种污染物的环境影响有广泛的了解。在这项研究中，我们尝试使用从土壤中培养的细菌群作为模型系统来评估镉和苯胺的单独和组合毒性作用的关系。结果表明，与从单一物种研究中获得的文献数据相比，共生细菌对单独的镉和苯胺表现出更强的耐受性。当同时发生时，联合毒性表现出浓度依赖性行为，这是根据单独的化学测试没有预料到的。具体而言，Cd和苯胺在IC ₁₀ s时表现出相加作用，但当浓度增加到IC ₂₀时变为协同作用，最后在IC ₃₀ s及以上时转变为拮抗作用。此外，相对于单独的镉处理，共存的苯胺似乎延缓了镉的细胞积累，同时增加了超氧化物歧化酶和过氧化氢酶的酶活性。最后，细菌群落在单独和组合毒性下经历了明显的组成变化，其中几个属在单一毒物和复合毒物处理之间表现出不一致的行为。这项研究的结果强调了细菌对复合污染反应的复杂性，并指出在多化学污染场所的风险和毒理学评估中需要更全面的参考资料。