Effects Of Temperature On Toxicity Of Danio Rerio Exposed To Triclosan

Triclosan(TCS,5-Chloro-2-2,4-Dichlorophenoxy Phenol)is a common and antibacterial chemical substance in our daily life.Although most of TCS is removed by wastewater treatment,a small amount of residual TCS will still enter the water and cause certain toxic effects on aquatic organisms.In this study,we chose zebrafish(Danio rerio),a model animal,as the research object,and the acute toxicity,growth and oxidative stress injury of TCS on D.rerio were detected at 20?,25?and 30?.In addition,hematoxylin-eosin(HE)staining was utilized to analyze the damage degree of TCS to D.rerio liver from the perspective of histology,so as to provide a vital theoretical basis for the rational use of TCS and the protection of fish living environment.The main conclusions of this study are as follows:1.The results of 96-h acute toxicity test indicated that temperature had a prominent effect on TCS toxicity.At 20?,25?and 30?,the half-lethal concentration of 96 h(96 h-LC₅₀)of TCS to D.rerio was 652.34?g/L,692.03?g/L and 744.81?g/L,respectively.Moreover,the toxicity of TCS was enhanced at low temperature.2.The results of 1-month chronic toxicity test suggested that TCS had certain effects on the body weight,respiratory frequency and tail wagging frequency of D.rerio under the conditions of 20?,25?and 30?,but the effect on body length was not obvious.There was an interaction between temperature and TCS concentration on toxicity to D.rerio.3.The results of HE staining on D.rerio liver revealed that the effect of TCS led to different degrees of hepatocytic lesions in D.rerio,and the cell spacing gradually increased with the rise of temperature.Taken together,the toxicity of TCS to D.rerio was different at different temperatures.As a result,in the context of global warming,on the one hand,the heavy use of TCS should be reduced,and on the other hand,temperature,a significant ecological factor,should be taken into consideration when determining the safe concentration of TCS.