Given the increased frequency of high magnitude floods in response to shifts in climate patterns, there is a need to understand the impacts of flooding beyond the immediate hydrological damage of the flood. Of particular concern is flood-induced mobilisation and distribution of contaminants: both legacy and emerging. This study aimed to assess spatial and temporal variation of contaminants of concern in floodwaters. Specifically, this study aimed to: (1) determine frequency and concentration of legacy (e.g. trace metals, per- and poly-fluoroalkyl substances (PFAS)) and emerging contaminants (e.g. pharmaceuticals, personal care products, endocrine disrupting chemicals (EDCs), phthalates) in water and sediment over a period of 3 weeks during floods; (2) quantify human wastewater contamination using E. coli and environmental DNA (eDNA); (3) convert concentrations to mass flux (i.e. total mass of substance moving through a given point on a watercourse) to account for hydrology and flow during floods. Water and sediment samples were analysed for 780 contaminants and the dataset comprises over 40,000 measured values. Of the 780 contaminants analysed, 81 were detected in water. The most frequently detected were fungicides (94.1% of sites), PFAS (94.1%), phthalates (88.2%), and polycyclic aromatic hydrocarbon (PAHs) (82.4%). Overall, the levels of contaminants measured were below Australian guidelines, except for PFOS. A total of 88% PFOS samples exceeded 99% species protection guideline (0.00023 μg/L) with concentrations ranging from 0.0002 μg/L to 0.0018 μg/L. For phthalates, the highest detection was for di-iso-octyl phthalate (0.81 μg/L). In addition, we discovered there was a lag of maximum risk with E. coli exposure, with the highest levels detected after peak flooding while water levels were receding. We will be presenting the study in full detail in the conference. To our knowledge, the number and breath of contaminants assessed, and the temporal and spatial scope of the study is unprecedented globally.