The OH content, 8-OhdG content, and CYP450 content were determined according to the method of Zhang et al. (2020) using a kit obtained from the ShangHai HengYuan Biological Technology Co., Ltd. (Shanghai, China). The OH content, 8-OHdG content, and activity of P450 in earthworms were detected by the double antibody sandwich method. The OH in earthworms combined with the antibodies of OH marked by HRP (Horseradish Peroxidase). Then, 3,3′,5,5′-tetramethylbenzidine (TMB) was added to produce a chromogenic reaction with the compound of antibody-antigen-antibody labeled by the enzyme. The absorbance of the reaction solution was recorded at 450 nm. The detection principle and method of 8-OhdG and CYP450 are the same as those of OH.