In this study, the occurrence of 12 organophosphorus flame retardants (OPFRs), 64 pesticides, 21 perfluoroalkyl substances (PFASs) and 34 pharmaceuticals and personal care products (PPCPs) in surface water, sediments and vegetation collected from seven locations along the South Riyadh and six locations along the Al-Jubail industrial city (Saudi Arabia) were reported. The median of the concentrations of ƩOPFRs, ƩPesticides, ƩPFASs and ƩPPCPs in water was 297, 231, 29.7 and 3794 ng L−1, respectively, in sediments 56.2, 40.4, 5.66 and 419 ng g−1 d.w., in crops for human consumption of 45.6, 42.0, 0.46 and 42.0 ng g−1, in farm crops of 13.4, 57.5, 3.2 and 637 ng g−1, and in natural vegetation of 51.7, 10.3, 1.88 and 1580 ng g−1. Predominant compounds in all matrices were tris-(1,3-dichloro-2-propyl)phosphate (TClPP), acetamiprid, imidacloprid, caffeine, bisphenol A (BPA), diclofenac and ibuprofen. Tris(2-butoxyethyl) phosphate (TBEP), tris-(2-ethylhexyl)phosphate (TPhP), perfluoroctanoic acid (PFOA), perfluoroalkyl sulfonate (PFOS) and paracetamol were also in many samples but at low concentrations. The contaminants' levels showed similar values in both cities. However, pesticide levels were significantly higher in surface water (p < 0.05) and lower in natural vegetation (p < 0.05) of Riyadh than those of Al-Jubail. The risk assessment for the aquatic biota showed that abamectin, diazinon (pesticides), bisphenol A and caffeine (PPCPs) had the highest risk levels. The cumulative risk assessment showed that the contaminant mixture in all water samples is of concern. As far as the risk to human health is concerned, individual contaminants did not show a significant hazard for the population. However, OPFRs and pesticide requires a closed monitoring since % of admissible daily intakes (ADIs) or reference doses (RfD) are high. This is one of the most comprehensive study covering environmental and human risk assessment of emerging contaminants carried out in Saudi Arabia.
