Temporal analysis of the cocaine metabolite benzoylecgonine in wastewater to estimate community drug use.

Indirect estimation methods of cocaine consumption may not reflect the real extent of cocaine use. Another approach is sewage epidemiology. This direct approach is based on analysis of a stable cocaine metabolite, benzoylecgonine (BE), in wastewater. Influent to the Lubbock (Texas) Water Reclamation Plant was sampled twice a week to assess weekly variations in estimates of cocaine consumption over a 5-month period. BE was extracted from influent wastewater samples using solid phase extraction and analyzed using gas chromatography/mass spectrometry. Measured concentrations of BE were converted to cocaine equivalents; the estimated average daily consumption of cocaine during the study period was 1152 ± 147 g. Based on BE concentrations and sewage epidemiology, higher cocaine consumption was observed on weekends compared to weekdays (p < 0.0003). This method was effective in monitoring BE in wastewater and could be used to complement survey data in estimating cocaine use at a local level.