title: Trends of Amphetamine Type Stimulants DTR Mass Load in Poznan Based on Wastewater Analysis.
abstract: BACKGROUND
  The aim of this study was to determine the monthly DTR mass load of amphetamine-type compounds in Poland as well as an investigation of cyclical behaviour by using time series analysis and especially trends analysis.
  
  
  METHODS
  Amphetamine, methamphetamine and MDMA (ecstasy) were detected in wastewater samples collected from the main Wastewater Treatment Plant in the city of Poznan using liquid chromatography / tandem mass spectrometry (LC-MS-MS). Back-calculations used in the sewage epidemiology approach were applied to estimate the DTR mass load level of the drugs analyzed. Trends analysis was performed by fitting the data to a simple linear regression and then by using smoothing by means of a moving average (Mat lab 2013a). Trend analysis displays a steady tendency of increase or decrease throughout time series. When we plot the observation against time, we may notice that a straight line can describe the increase or decrease in the series as time goes on. Simple linear regression and method of last squares to estimate parameters of a straight-line model were used. Additionally, a lagged plot (autocorrelation plot) was used to investigate an appearance of correlation between amphetamines throughout time.
  
  
  RESULTS
  Trends analysis showed the slight increase in consumption of amphetamine and decreasing trend in case of ecstasy and methamphetamine within the investigated period. There is also visible, strong correlation between ecstasy and methamphetamine consumption which cannot be stated in case of amphetamine.
  
  
  CONCLUSIONS
  Trends analysis is a very useful tool to analyse the increasing or decreasing tendency in consumption of illicit drugs based on the DTR mass load data.
authors.affiliation: Dept. of Inorganic and Analytical Chemistry, Poznan University of Medical Sciences , Poznan, Poland.
authors.forename: Piotr
authors.initials: P
authors.lastname: Nowicki
authors.affiliation: Dept. of Inorganic and Analytical Chemistry, Poznan University of Medical Sciences , Poznan, Poland.
authors.forename: Jolanta
authors.initials: J
authors.lastname: Klos
authors.affiliation: Dept. of Inorganic and Analytical Chemistry, Poznan University of Medical Sciences , Poznan, Poland.
authors.forename: Zenon J
authors.initials: ZJ
authors.lastname: Kokot
keywords: Amphetamines; HPLC-MS/MS; Illicit drugs; Time series; Wastewater