From hydraulic fracturing additive use to produced water signatures: a screening and prioritization framework

Hydraulic fracturing (HF) generates large volumes of flowback and produced water (PW), yet the downstream relevance of injected additives remains poorly understood. Using 2020–2025 FracFocus disclosures, published chemical property information, and literature-reported PW evidence, we developed a basin-comparative screening and prioritization framework that integrates HF-event-level use relevance, fate/PW expression potential, hazard relevance, and treatment/process relevance, with evidence confidence evaluated separately and time-resolved source-term scenarios used to examine potential PW expression. Applied to 33,177 HF events in the Permian and San Juan basins, the framework identified biocides, solvents, and surfactants as the leading composite-relevance categories in the Permian, and acids, biocides, and solvents in the San Juan. Leading priorities were generally retained across sensitivity and uncertainty analyses. Mature PW salinity, major ions, metals, radionuclides, and much of the ammonia burden were predominantly formation/process controlled, whereas additive related influences were more relevant to the flowback-to-PW transition, mobile organics, toxicity related constituents, fouling, scaling, and other treatment process effects. Comparison with independent literature reported PW data provided directional external consistency for these interpretations. The framework supports basin- and production-stage-specific monitoring and treatment/reuse prioritization, but it is intended for screening rather than chemical-source attribution, predictive validation, or site-specific concentration or exposure prediction.