Normalized diurnal and between-day trends in illicit and legal drug loads that account for changes in population.
Drug concentrations in composite municipal wastewater samples and census-based estimates of population are used to derive daily loads of illicit substances that are indexed to population. However, such estimates do not provide information on the diurnal trends of substance excretion nor can they account for changes in population. To address these limitations, a series of 1 h composites created by sampling wastewater influent at 6 min intervals was collected over four consecutive days at a single wastewater treatment plant. Creatinine (a urinary indicator), caffeine, methamphetamine, benzoylecgonine (BZE), and cocaine were analyzed by liquid chromatography/tandem mass spectrometry (LC-MS/MS). Diurnal trends and between-day trends were substance specific and related to the number of estimated doses and excretory half-life. Normalization to creatinine yielded trends in substances that differed significantly from non-normalized trends by accounting for changes in population within the municipality studied. Increases in normalized substance excretion observed during early morning hours originate from individuals among the resident population of the municipality due to the absence of commuters.
Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, Oregon, USA.
Alex J
AJ
Brewer
Christoph
C
Ort
Caleb J
CJ
Banta-Green
Jean-Daniel
JD
Berset
Jennifer A
JA
Field
D002853:Chromatography, Liquid; D002940:Circadian Rhythm; D003404:Creatinine; D006207:Half-Life; D013287:Illicit Drugs / Q000032:analysis*; D053719:Tandem Mass Spectrometry; D035501:Uncertainty; D062065:Wastewater
D003404:Creatinine; D013287:Illicit Drugs; D062065:Wastewater