| Since the novel coronavirus(COVID-19)outbreak in 2019,there has been a significant increase in the use of drugs used to control and prevent COVID-19.Due to inability to be fully digested by patients and improper treatment,anti COVID-19 drugs may only be partially metabolized and not completely removed during conventional wastewater treatment.Drugs and their metabolites are released into the water environment,and drug concentrations in the water environment continue to increase,posing a potential threat to human health and aquatic ecological security.At the same time,due to the large-scale spread of viruses,enhanced disinfection leads to the inflow and release of a large amount of disinfectants in surface water,which may cause the formation of disinfection by-products(DBPs)in the presence of drugs.The disinfectants added during the disinfection process have a certain degradation effect on the drugs through processes such as chlorination reactions.DBPs are by-products produced by the interaction of disinfectants added in water treatment processes with organic or inorganic substances,and have been widely proven to have negative effects on human health.Although the synergistic effects of disinfectants and dissolved organic compounds on the formation of DBPs in the aquatic environment have been extensively explored,the study of the oxidative decomposition behavior of antiviral drugs and their secondary DBPs risks in different disinfection processes has been greatly limited.After disinfection of drinking water with antiviral drugs in different ways: chlorine,UV/chlorine,chlorine dioxide,chloramine,and ozone,The degradation of antiviral drugs and the formation of disinfection by-products are still unclear.Therefore,based on the current situation of DBPs generated from drug use during the NIV outbreak in China,eight drugs widely used during the NIV fight were selected and the experimental method was used to explore the types of disinfection by-products generated after chlorine disinfection and to compare them.The effects of chlorine addition,reaction time,p H,humic acid concentration and microplastic concentration on their production were also evaluated and their Biotoxicity was analysed.Anti-virals,which are the most abundant and less explored of the eight drugs,were selected as target compounds to investigate their degradation processes,patterns and effects under each of the five different disinfection methods.The details of the study are as follows:(1)Eight anti-Neovirus drugs-ibuprofen,aspirin,ritonavir,lopinavir,dexamethasone,methylprednisolone,norfloxacin and erythromycin-were selected as targets and the types of disinfection by-products generated by the drugs after chlorination disinfection were determined using GC-ECD.In addition,the factors influencing the process of disinfection by-product generation were also evaluated.For example,the amount of chlorine added,reaction time,p H,humic acid concentration and microplastic concentration.The experimental results showed that trihalomethanes,as one of the disinfection by-products,had a higher yield and were the dominant species in the production process,and that increasing chlorine addition and reaction time promoted the production of disinfection by-products;at p H > 7 HCl O decreased and the number of active molecules in the reaction decreased,thus reducing the production of disinfection by-products;humic acid had little effect on the production of pharmaceutical disinfection by-products,and the addition of humic acid solution The disinfection by-products generated after the addition of humic acid solution are the sum of the by-products generated by the individual reactions;however,after the addition of microplastics,the amount of disinfection by-products generated by the drug decreases significantly at first due to the adsorption effect of microplastics on the drug.(2)The antiviral drugs,ritonavir and lopinavir,were selected for study to examine the types of disinfection by-products generated in five different disinfection processes: chlorine,UV/chlorine,chlorine dioxide,chloramine and ozone,and to conduct a comparative study.The results showed that sodium hypochlorite produced significantly more disinfection by-products than the other two chlorine disinfection processes;ozone disinfection mainly produced brominated disinfection by-products containing bromine and more in an alkaline environment;and UV/chlorine combination process,UV radiation promoted the production of disinfection by-products in a short period of time.(3)Ritonavir and lopinavir,the antiviral drugs,were selected for the study and their degradation patterns were investigated in five different disinfection processes: chlorine,UV/chlorine,chlorine dioxide,chloramine and ozone,using liquid chromatography.The effects of disinfectant dosage and p H on the degradation process were also investigated.The experiments showed that the combined UV/chlorine disinfection process had the best degradation effect of 80%;in the ozone disinfection process,the degradation efficiency of the drugs reached 30%;as the antiviral drugs contained active functional groups such as amine groups,they could also be degraded to a certain extent in the chlorination disinfection process.(4)Biotoxicity analysis of neocrown-related drugs before and after disinfection was carried out,and experiments were conducted using a biotoxicity detector as well as the in vivo luminescence of luminescent bacteria,using Vibrio maritimus as the target,to investigate the inhibitory effects of neocrown-related drugs on luminescent bacteria under different disinfection conditions.The results found that anti-inflammatory and analgesic drugs were themselves more effective in inhibiting the bacteria,with less change before and after chlorination,and that glucocorticoids produced new substances after chlorination and disinfection,making them sharply more toxic.The relative toxicity inhibition of the drugs became weaker after disinfection due to the stronger degradation of the drugs by the ozone and UV/chlorine disinfection methods. |
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