Non-target screening and resistome profiling of hospital wastewater in India: Transformation of contaminants of emerging concern and antimicrobial resistance risks.

Hospital wastewater (HWW) is a critical reservoir of contaminants of emerging concern (CECs), antibiotic resistant bacteria (ARB) and genes (ARGs), and a major hotspot for accelerating the spread of antimicrobial resistance (AMR). Despite this, occurrence data remain scarce in India, especially for contrast agents and parabens. For Indian scenario, this study acts as the first account of non-targeted analysis (NTA) coupled with liquid-chromatography-high-resolution mass-spectrometry (LC-HRMS) for characterizing the CECs in the effluents of three hospitals in Delhi region. 728 CECs were tentatively identified, of which 38 were structurally confirmed (at level 2) and 23 quantified. Pharmaceuticals dominated the CEC profile, with antibiotics being the predominant subclass (concentrations of 44-3509 ng/L). Iohexol was detected at high concentration of 80 µg/L, further its toxic transformation products (TPs) were identified during HWW treatment. The effluent treatment plant (ETP) was ineffective in removing CECs, including antibiotics, implying AMR spread. Amoxicillin, levofloxacin, and azithromycin (along with antibiotic TPs) exhibited AMR risk (RQAMR>1), with detection of WHO priority and ESKAPE pathogens- Acinetobacter baumannii, Klebsiella sp., Pseudomonas aeruginosa, and Enterobacter sp. in the treated effluent. Out of 51 ARGs identified, 14 of them belonged to the efflux mediated multidrug resistance class. With HWW discharged directly into municipal sewers, there could be overburdening of urban treatment networks with CECs and spread of AMR. This study provides one of the most comprehensive datasets on CECs, their TPs, ARBs and ARGs in Indian HWW and underscores the urgent need of upgradation of existing ETPs and integrated AMR surveillance.