Characteristic Of Typical Chiral PPCPs In WWTPs Of Beijing

Pharmaceutical and personal care products(PPCPs)as an important group of emerging micropollutants,have received much attention in recent years due to their wide use and continuous detection,and potential adverse effects on ecosystem and human health.Most of PPCPs are chiral PPCPs,which are usually consumed as racemic compounds or single enantiomers.WWTPs identified as the main point source of chiral PPCPs into environment.Most studies in our country just focus on the concentration detection of PPCPs neglect stereoselectivity.The difference of the affinity between enzyme and substrate or the different chiral compounds could lead to stereoselectivity of chiral pharmaceuticals during biodegradation process.In order to accurately understand about the occurrence and level of chiral PPCPs at enantiomeric level,method about analysis chiral PPCPs was developed.It is also foundation to gain a better elucidation of their transport and transformation,as well as the assessment of their environmental risk.The results are as follows.First,a method for the determination of 5 common chiral PPCPs(atenolol,metoprolol,propranolol,fluoxetine and venlafaxine)and 5 chiral metabolites(metoprolol avid,?-OH metoprolol,norfluoxetine,O-desmethylvenlafaxine and N,O-Didesmethylvenlafaxine))in water and sludge was developed.The method based on ultrasonic extraction and solid phase extraction(SPE),using Chirobiotic V and guard column under a mobile phase composed by 10% 10 mM ammonium acetate(pH=4,adjust by formic acid)and 90% methanol using isocratic conditions,combined ultra-performance liquid chromatography tandem mass spectrometry(UPLC-MS/MS).Second,the influent and effluent,as well as treatment units of five WWTPs in Beijing were monitored to gain the occurrence of chiral pharmaceuticals.The results showed that total nine chiral pharmaceuticals were determined,and the concentration of ATN was lower than that in other countries,but other pharmaceuticals were similar order of magnitude with those in other countries.O-desmethylvenlafaxine with a considerably greater level of concentration was also detected,approximately 2 times higher than its parent compounds.The significant stereoselectivity of metoprolol has been observed during the A2/O-MBR process,whereas EFs of other pharmaceuticals present small fluctuations.For removal metoprolol,A2/O-MBR process was better than oxidation ditch(OD).The last point,batch experiments were conducted to investigate the effects of different initial concentrations and pH values on the removal of metoprolol,propranolol and venlafaxine in the activated sludge.The results indicated that fluoxetine dissipated from aqueous phase,mainly due to the adsorption to sludge.High concentration inhibited degradation of target compounds.Propranolol was easily biodegraded than metoprolol and venlafaxine at low concentration.The R-enantiomer of metoprolol is easily biodegraded than S-enantiomer,leading the decrease of EF.The different existing forms of pharmaceuticals in different pH buffer depend on their pKa.Metoprolol,propranolol and venlafaxine exist in the form of cation due to their pKa were over 8,which had an interaction with negatively charged microorganisms.The biodegradation rate increased with the pH values increasing from 5 to 8.The best pH value was 8.