Identifying drivers of sewage-associated pollutants in pollinators across urban landscapes

Human sewage can introduce pollutants into food webs and threaten ecosystem integrity. Among the many sewage-associated pollutants, pharmaceuticals and personal care products (PPCPs) are consistent indicators of sewage in ecosystems and can also cause potent ecological consequences, even at minute concentrations (e.g., ng/L). Despite increased study over the past three decades, PPCPs in terrestrial ecosystems have been less studied than those in aquatic ecosystems. To evaluate PPCP prevalence and drivers in a terrestrial ecosystem, we analyzed managed and native bees collected from agroecosystems in Washington State (USA) for PPCPs. Caffeine, paraxanthine, cotinine, and acetaminophen were detected in all three evaluated taxa (Bombus vosnesenskii, Agapostemon texanus, and Apis mellifera), with B. vosnesenskii and A. texanus having a higher probability of PPCP detection relative to A. mellifera. The probability of PPCP presence in all three taxa increased in landscapes with more human development and greater plant abundance, with significant but negative interactions among these factors. These results suggest that human activity, availability of resources, and species-specific pollinator traits affect the introduction and mobilization of PPCPs in terrestrial ecosystems. Consequently, monitoring PPCPs and their ecological responses in terrestrial ecosystems creates opportunities to synthesize effects of sewage pollution across terrestrial and aquatic ecosystem types and organisms.