Multiple pesticides often coexist in soil, potentially leading to interactions among their components, these may detrimentally impact soil organisms. This study assessed the potential risks posed by simultaneous exposure to atrazine (ATR) and phoxim (PHO) on enzyme and transcription levels in earthworms (Eisenia fetida). The results revealed that ATR exhibited higher acute toxicity towards E. fetida compared to PHO, and their combined exposure resulted in a synergistic acute effect. Furthermore, low concentration combined exposure significantly stimulated catalase (CAT), malondialdehyde (MDA), and total superoxide dismutase (T-SOD) activities, which lead to more severe oxidative damage. Elevated expression levels of translationally controlled tumor protein (tctp) and calreticulin (crt) genes were observed in most exposed groups compared to the control. The synergistic effects of ATR and PHO on earthworms observed in this study may pose ecological risks to the soil ecosystem; thus, more attention should be paid to the joint effects of different pesticides.

Farmland soil organisms frequently encounter pesticide mixtures presented in their living environment. However, the underlying toxic mechanisms employed by soil animals to cope with such combined pollution have yet to be explored. This investigation aimed to reveal the changes in cellular and mRNA levels under chlorpyrifos (CPF) and lambda -cyhalothrin (LCT) co-exposures in earthworms ( Eisenia fetida ). Results exhibited that the combination of CPF and LCT triggered an acute synergistic influence on the animals. Most exposures resulted in significant alterations in the activities of total superoxide dismutase (T -SOD), copper/zinc superoxide dismutase (Cu/Zn-SOD), caspase 3, and carboxylesterase (CarE) compared to the basal level. Moreover, when exposed to chemical mixtures, the transcription levels of four genes [heat shock protein 70 ( hsp70 ), gst , sod , and calreticulin ( crt )] also displayed more pronounced changes compared with their individual exposures. These changes in determined parameters indicated the occurrence of oxidative stress, cell death, detoxification dysfunction, and endoplasmic reticulum damage after co-exposure to CPF and LCT in E. fetida . The comprehensive examination of mixture toxicities of CPF and LCT at different endpoints would help to understand the overall toxicity they cause to soil invertebrates. The augmented deleterious effect of these pesticides in a mixture suggested that mixture toxicity assessment was necessary for the safety evaluation and application of pesticide mixtures.