Occurrence of areca alkaloids in wastewater of major Chinese cities

Areca nut is a widely used psychoactive product that can cause multiple health problems, such as oral and pharyngeal cancers. Therefore, it is important to estimate areca nut use and the exposure levels of areca alkaloids that are responsible for its health effects. China is a major producer of areca nut and has a large number of areca nut chewers. In this study, occurrence of areca alkaloids and metabolites in wastewater of major cities across China was examined via wastewater-based epidemiology (WBE). Arecoline, arecaidine, and their metabolite, N-methylnipecotic acid (NMNA) were detected in the overwhelming majority of wastewater samples, with concentrations up to several μg/L. In contrast, guvacoline was only occasionally detected and guvacine was below detection limit in all samples, possibly due to their low contents in areca nut products, low excretion rates, and/or low stability in sewer systems. Strong positive correlations existed between arecoline, arecaidine, and NMNA concentrations. In addition, their loads were much higher in Central and Southern China. This geographic pattern is consistent with previous survey results on prevalence of areca nut chewing. These results indicate that WBE is a potentially useful method to monitor areca nut consumption and to estimate the exposure levels of areca alkaloids.