Cross-enterprise occurrence patterns and monitoring priorities of shared organic contaminants in pharmaceutical wastewater.

Pharmaceutical manufacturing wastewater contains diverse organic chemicals, yet contaminants recurrently detected across enterprises remain insufficiently characterized. In this study, composite effluents from the final discharge outlets of ten pharmaceutical enterprises in China were analyzed using liquid chromatography-high-resolution mass spectrometry-based non-target screening. Principal component analysis, exploratory Spearman co-variation analysis, BIOWIN biodegradability prediction, predicted no-effect concentration (PNEC) evidence evaluation, and a peak-area-based screening-level prioritization framework were integrated to characterize shared contaminants and identify candidates for follow-up monitoring. A total of 1862 features were detected, and 347 compounds across 20 chemical classes were annotated. Fourteen contaminants detected in all ten enterprises were selected based on MS/MS matching and relative peak-area criteria. Their relative LC-HRMS signal profiles varied mainly along a continuous cross-enterprise gradient, while several contaminant groups showed synchronous variation across samples. BIOWIN classified eight shared contaminants as readily biodegradable and six as not readily biodegradable. By jointly considering predicted biodegradability, PNEC evidence quality, relative peak-area signals, and annotation confidence, norethindrone and norgestrel were identified as high-priority candidates for screening-level monitoring. C12-AE1S remained a tentative tracking candidate requiring structural confirmation and treatment-behavior evaluation. These findings indicate that monitoring priorities should not be determined by detection frequency or relative LC-HRMS signal intensity alone. This screening approach provides a practical basis for selecting recurrent contaminants for targeted quantification, source investigation, and treatment verification in pharmaceutical wastewater.