| Triclocarban（Triclocarban,TCC）is a typical representative of pharmaceuticals and personal care products（PPCPs）.It is a broad-spectrum antimicrobial agent commonly used in personal care products,and is closely related to human life.Due to the hydrophobicity and chemical stability of TCC,it has been omnipresent detected in soil,sludge,sediment,etc.,and it is difficult to remove in the environment through degradation methods.Its prolonged exposure has thrown potential pernicious threat to ecosystem and human health.Cadmium（Cd）is the heaviest and most common heavy metal in soil than other heavy metals.It is one of the most environmentally toxic,bioavailable,and highly mobile elements in the environment.In the soil,soil environmental pollution is aggravated,thereby increasing the probability that TCC and heavy metals Cd coexist in the soil.In order to evaluated the the combined action potential toxicity of TCC and Cd to soil ecosystem,different concentrations of TCC were used to observe effects on Eisenia fetida in artificial soil.The activities of antioxidase system and detoxify enzyme,reactive oxygen species（ROS）contents,levels of malondialdehyde（MDA）,as well as DNA damage in earthworms were measured after exposure to 0,5,10,20 and 40 mg·kg-11 TCC in artificial soil for 7,14,21,and 28 days.It can provide a basis for further evaluation of TCC’s toxic effects,ecological risks and improvement of relevant standards.The main test results are as follows:（1）Under the single stress of TCC,the SOD and POD activities of each concentration treatment group showed a tendency of first activation and then inhibition.CAT in the 40mg·kg-11 treatment group was always inhibited throughout the experimental period,indicating that high concentration of TCC on CAT The stress was too heavy;the GST activity reached the highest at 14 days,and the activation increased significantly with the increase of the exposure concentration.During the entire exposure period,the MDA and ROS contents of the treatment group were higher than those of the control group;28 days after the exposure,the ROS content began to fall and approached the blank level,indicating that the body has a certain self-repairing ability;Olive tail moment and the degree of DNA damage increased with the increase of TCC concentration.（2）Effects of TCC and Cd on enzyme activity in earthworm:Under the combined effect of TCC and Cd,TCC and Cd showed a certain antagonistic effect at the initial stage of the test,and TCC and Cd as a whole acted synergistically at the later stage of the test.（3）Oxidative stress of TCC-Cd combined pollution on earthworms:TCC-Cd combined pollution on earthworms at the early stage of poisoning.The contents of SOD,POD,GST,and ROS showed a certain antagonism.With the increase of the exposure time,showed a synergistic effect;at the beginning of the exposure,the low concentration TCC(5,10 mg·kg-1)compound group,CAT activity and MDA content showed a certain antagonism,and later showed a synergistic effect,while the high-concentration TCC-Cd composite group always showed a synergistic effect.（4）DNA damage to earthworms by TCC-Cd combined pollution:the OTM value of earthworm cells increases with the exposure time and TCC concentration.This shows that TCC-Cd has a certain synergy when compounded,and TCC-Cd compound aggravates DNA damage. |
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