Dissolved organic matter (DOM) strongly influences the properties and fate of engineered nanoparticles (ENPs) in aquatic environments. There is an extensive body of experiments on interactions between DOM and ENPs and also larger particles. [We denote particles on the nano-and micrometer scale as particulate matter (PM).] However, the experimental results are very heterogeneous, and a general mechanistic understanding of DOM-PM interactions is still missing. In this situation, recent reviews have called to expand the range of DOM and ENPs studied. Therefore, our work focuses on the diversity of the DOM and PM types investigated. Because the experimental results reported in the literature are highly disparate and difficult to structure, a new format of organizing, visualizing, and interpreting the results is needed. To this end, we perform a network analysis of 951 experimental results on DOM-PM interactions, which enabled us to analyze and quantify the diversity of the materials investigated. The diversity of the DOM-PM combinations studied has mostly been decreasing over the last 25 y, which is driven by an increasing focus on several frequently investigated materials, such as DOM isolated from fresh water, DOM in whole-water samples, and TiO 2 and silver PM. Furthermore, there is an underrepresentation of studies into the effect of particle coating on PM-DOM interactions. Finally, it is of great importance that the properties of DOM used in experiments with PM, in particular the molecular weight and the content of aromatic and aliphatic carbon, are reported more comprehensively and systematically.nanoparticles | dissolved organic matter | environmental fate | network analysis | experimental design T he development and use of nanotechnology results in the release of engineered nanoparticles (ENPs) to the environment (1, 2). Much effort in current research is put into assessing the environmental risks of ENPs, which requires the understanding of the fate and distribution of ENPs in different environmental media, as well as their potential toxicity (3-6). Dissolved organic matter (DOM) (e.g., humic substances, polysaccharides, and proteins) is ubiquitous in aquatic systems and is known to interact with ENPs and modify their surface properties (7). DOM has been shown to either stabilize or destabilize aqueous ENP suspensions, depending on DOM properties and medium composition (8, 9). The effects of DOM on the stability of ENP suspensions are expected to strongly influence the mobility and distribution of ENPs in the environment (10).The extraordinary variability in DOM effects on ENPs originates from the fact that the interactions between DOM and ENPs depend on numerous interrelated factors, such as pH and ionic strength of the media, the particles' surface properties and size, and the chemical composition and concentration of the DOM (11). Some types of DOM, such as fulvic and humic acids, electrostatically stabilize ENPs via the adsorption of the electrically charged DOM on the ENP surface (12-16), where the str...