An evidence synthesis of the environmental PPCP literature: Imbalance in compounds, sewage treatment techniques, and ecosystem types

Pharmaceuticals and personal care products (PPCPs) garner increasing attention globally for both their usefulness as indicators of sewage and their potency as emerging toxicants. We review three decades (6,500+ abstracts) of PPCP study (1) to review trends in diversity of compounds, sewage treatment techniques, and ecosystems investigated as well as (2) to identify knowledge gaps in the literature. Discrepancies within the literature highlight distinct opportunities to address knowledge gaps, including underrepresented compounds (e.g., fragrances), sewage treatment techniques (e.g., septic systems), and ecosystem types (e.g., lakes).