Investigation Of Ketamine Abuse In Dalian Based On Sewage Epidemiology

Ketamine is a commonly used anesthetic in clinic.It has a certain potential for mental dependence and is the second most abused synthetic drug besides methamphetamine.At present,the abuse of ketamine among general population in our country is lack of statistical data.The development of sewage epidemiology is a novel approach to investigate the prevalence of illicit drug abuse.The method is based on the analysis of the drug residues in the influent,and by combining the metabolic data of the drug,the flow rate,and population of the sewage treatment plant,the prevalence of illicit drug can be estimated.It is important to accurately analyze the low concentration of drug residues in municipal wastewater.As the biomarker of ketamine,norketamine was used to predict the quantity of ketamine abuse.However,norketamine molecular structure containing more polar amino group,which absorbs on the active sites in chromatographic system,resulting in gas chromatography peak tailing and low response.It is difficult to quantitatively norketamine in wastewater samples.A trifluoroacetic anhydrid derivatived with norketamine and gas chromatography mass spectrometry method was developed for the determination of norketamine in wastewater.The optimization of derivative conditions was set to the temperature of 70 degrees,time 30 min and dose 20?L.In November 2015,August 2016,and August 2017,wastewater samples were collected in 11 wastewater treatment plant in Dalian with average concentration of norketamine were 4.18±4.56 ng/L,2.37±2.14 ng/L and 5.07±3.95 ng/L.The mean mass loads per capita were in the range of 0.8?1.7 g/d,which is similar the values in general Chinese cities,but significantly lower than that of Guangzhou,Shenzhen and Hongkong.Monte Carlo analysis showed that the median of ketamine abuse in Dalian was 26.3 ?g/d(95%CI:15.4?90.7 ?g/d).The median prevalence of ketamine abuse among adults aged 15-64 years in Dalian,2015?2017,was 0.05%(95%CI:0.01?0.19%).The results show that the sewage epidemiology can continuously investigate the abuse of ketamine and provide real-time drug abuse data for the public security against drug abuse.