Distribution Of 13 Polar PPCPs In A River Basin Of Beijing-Tianjin-Hebei And Modeling Transformation Of PPCP Under Denitrifying Conditions

Pharmaceuticals and personal care products(PPCPs)are a kind of emerging contaminants.The last two decades have witnessed the ubiquitous emergence of PPCPs in environmental matrices,such as surface water,ground water,soils and sediments.An important source of these organic compounds is the discharge of effluents from wastewater treatment plants into surface water bodies.They also come from solid waste disposal,spills and uncontrolled discharges from industries,spreading of manure and sewage sludge as organic fertilizer in agricultural soils,surface run-off,and so on.Their concentrations are usually in the ng/L to ?g/L range.Still,they are a cause of concern because of their potential chronic effects and synergic action of their mixtures on aquatic life and human health.An analytical method was developed to simultaneously determine 13 pharmaceuticals and personal care products(PPCPs)in water sample with solid phase extraction and ultraperformance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS).The extracts were concentrated and cleaned up with HLB cartridge coupled with WAX cartridge.Gradient elution was performed using acetonitrile and 0.1% formic acid solution for UPLC method.The mass spectrometric acquisition was carried out by means of multiple reaction monitoring(MRM)in positive ionization mode.The limits of detection(LOD)and quantitation(LOQ)for the 13 PPCPs were 0.007 ng/L-1.1 ng/L and 0.02 ng/L-3.8 ng/L,respectively.The mean recoveries were in the range of 54%-97%.The proposed method was used to determine the 13 PPCPs in surface water and groundwater of Beijing-Tianjin-Hebei.The detection rates of 13 target objects reached the highest level in surface water,with a range from 69.2% to 92.3%,and the highest concentration was 906.71 ng/L.In the surface water samples of water source,the detection rate of 13 PPCPs was 30.8%,and the highest concentration was only 8.50ng/L.In addition,the detection rates in groundwater was 30.8%-53.8%,and the concentration range was 0.32 ng/L-10.89 ng/L.The results demonstrated that the method is selective,easy to operate,sensitive,and therefore can be used in the routine detection of PPCPs in water sample.SMZ was used as an example to further study the transformation of PPCP under denitrifying conditions.During the denitrifying degradation experiment SMZ was no longer detected about 15 days later whereas increasing concentrations of the two TPs,4-nitro-N-(5-methylisoxazol-3-yl)-benzenesulfonamide(4-SMZ)and N-(5-methylisoxazol-3-yl)-benzenesulfonamide(D-SMZ),were observed.However,at day 87 the SMX concentration recovered to 40±17% of the initial concentration after most of the nitrate was consumed.A retransformation of 4-SMZ to SMZ was postulated.Furthermore,the experimental results showed that the transformation of SMZ was also affected by sediment samples and organic acids.