Fig. 1.

Co-occurrence network with timeline showing overlay visualization of keywords extracted from the literature associated with emerging contaminants. The bibliographic search was conducted on the Web of Science database, and the keywords used for article searching were “New contaminant∗” or “New pollut∗” or “Emerging contaminant∗” or “Emerging pollut∗”, with only research articles published from January 1990 to December 2021 included. The circle size reflects the number of co-occurrence links of each keyword, and the line color represents the average published year of each keyword.