Studies On The Adsorption Behavior Of Antibiotics On Microplastics And Its Related Toxicity

Microplastics are easy to form a composite system with other pollutants due to their small particle size and strong hydrophobicity,thus changing their environmental behavior.At present,most of the research objects on the adsorption behavior of microplastics are Polycyclic aromatic hydrocarbons?heavy metals,and there are few studies on the adsorption behavior of antibiotics.In addition,most of the research objects on the toxicity of microplastics are mainly plastic microspheres,and there is a lack of research on the additives such as plasticizers and flame retardants used in the production process of plastics.Based on this,this article in order to widely distributed in the environment of antibiotics(amoxicillin,ciprofloxacin,tetracycline)as a pollutant,under different environmental media have been studied the adsorption behavior of antibiotics in the micro plastic,and simulate the aging condition of microplastics in the environment with ultraviolet light,the toxicological genomics method was used to study the toxicity evolution and mechanism of the mixture of microplastics,plastic additives,microplastics and antibiotics under ultraviolet degradation.The conclusions were as follows:(1)The adsorption capacity of the three antibiotics(AMX?CIP?TC)on the microplastics conforms to the pseudo-second-order dynamic model and the Freundlich model.The adsorption capacity is CIP>AMX>TC,and the adsorption capacity is positively correlated with the hydrophobicity of the antibiotics.(2)Toxicity of ultraviolet degradation exudate of four kinds of microplastics: Polystyrene(PS)> Polyvinyl chloride(PVC)> Polypropylene(PP)> Polyethylene(PE),37% of the genes expressed are co-expressed,which means that the exudate of four kinds of microplastics can cause similar or identical biological effects by regulating the same gene,which is mainly related to oxidative stress.(3)The common toxic action patterns(MOA)of eight plastic additives are basically consistent with the relevant literature reports.Will be measured by the micro plastic and plastic additive gene expression changes induced by hierarchical clustering analysis of the data,theresults showed that with the same chemical structure(micro plastic exudate)and the result of similar adverse reactions(belong to environmental endocrine disruptors additives)usually converge class together,suggests that it may have a similar adverse reaction pathway and mechanism of toxic effects.The results of principal component analysis were consistent with the results of cluster analysis,and the additive bisphenol A(BPA)had a very high correlation with the four kinds of microplastics,indicating that the microplastics might be released with similar substances to BPA.(4)The dual toxicity of microplastic PVC combined with antibiotics AMX and CIP was significantly stronger than that of microplastic PVC alone,with significant differences(P<0.05).The toxic pathways were membrane stress,general stress and DNA stress.The toxicity of microplastic PS mixed with antibiotics AMX,CIP and TC was weaker than that of microplastic PVC alone,but there was no significant difference after t test(P>0.05).The dual toxicity of microplastic PP and PS combined with antibiotics was no obvious change than of microplastic alone.(5)Principal component analysis results of different stress pathways induced by microplastics,antibiotics and their mixtures showed that the mixed toxicity of microplastics and antibiotics was divided into three conditions :(a)the mixed toxicity was not similar to that of a single component,such as microplastic PVC and antibiotic AMX;(b)the mixed toxicity is similar to that of microplastics,such as microplastic PVC and the antibiotic CIP;(c)mixed toxicity is similar to antibiotic toxicity,such as microplastic PVC and antibiotic TC,and microplastic PS and three antibiotics.