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Iodinated contrast media (ICM), one of the pharmaceutical and personal care products (PPCPs), are frequently detected in various water bodies due to the strong biochemical stability and recalcitrance to conventional water treatment. Additionally, ICM pose a risk of forming iodinated by-products that can be detrimental to the aquatic ecosystem. Consequently, effectively removing ICM from aqueous environments is a significant concern for environmental researchers. This article provides a comprehensive review of the structural characteristics of ICM, their primary source (e.g., domestic and hospital wastewater), detected concentrations in water environments, and ecological health hazards associated with them. The current wastewater treatment technologies for ICM control are also reviewed in detail with the aim of providing a reference for future research. Prior researches have demonstrated that traditional treatment processes (such as physical adsorption, biochemical method and chemical oxidation method) have inadequate efficiencies in the removal of ICM. Currently, the application of advanced oxidation processes to remove ICM has become extensive, but there are some issues like poor deiodination efficiency and the risk of forming toxic intermediates or iodinated by-products. Conversely, reduction technologies have a high deiodination rate, enabling the targeted removal of ICM. But the subsequent treatment issues related to iodine (such as I− and OI−) are often underestimated, potentially generating iodinated by-products during the subsequent treatment processes. Hence, we proposed using combined reduction-oxidation technologies to remove ICM and achieved synchronous control of iodinated by-products. In the future, it is recommended to study the degradation efficiency of ICM and the control efficiency of iodinated by-products by combining different reduction and oxidation processes. [Display omitted] • Overview of ICM environmental pollution and fate. • Poor deiodination efficiency of ICM and the generation of iodinated by-products in AOPs. • High deiodination rate in reduction methods but removed iodide poses potential risk. • Combine reduction and oxidation processes to remove ICM and control I-DBPs. [ABSTRACT FROM AUTHOR]

The seasonal succession of phytoplankton assemblages is important to ascertain the dynamics of an aquatic ecosystem structure, whereas its occurrence in response to hydrodynamic alterations is not clearly understood. In view of the characteristics of annual water level variation formed by the Three Gorges Dam Project (TGDP), our understanding about how these changes affect phytoplankton structure and dynamics is still very limited due to the shortage of long-term observation data. In this study, we used Huan Jing 1 charge-coupled device images over the past decade to examine the phytoplankton succession dates between cyanobacterial and green algal blooms in the backwater area of the Three Gorges Reservoir (TGR). The results indicated continuous wavelet transform-based peak analysis is an efficiency tool that can illustrate the temporal pattern of phytoplankton succession using satellite-derived chlorophyll ɑ and Cyano-Chlorophyta index thresholds. Water level, air temperature, pH and total nitrogen/total phosphorus ratio were four important factors affecting the decline and rise phase of cyanobacterial blooms in the TGR from 2008 to 2018. Given that the upstream dam operation is likely to alter ecological and environmental conditions in the backwater area, this mechanism, so-called "water-level linkage", could alleviate the persistent period of cyanobacterial and green algal blooms. Remote sensing together with time series analysis provided a useful method to examine the seasonal succession of phytoplankton assemblages in the TGR, and these findings provided strategic insight for the water-quality management in the post-TGDP period. • Phytoplankton succession in the Three Gorges Reservoir in 2008–2018 was investigated. • Cyanobacterial and green algal blooms are delineated using Chlɑ and CCI thresholds. • Wavelet transform-based peak analysis is used to detect abrupt change in time series. • Water-level linkage mechanism appears to prevent the algal bloom formation. [ABSTRACT FROM AUTHOR]

Although the fates of microplastics (0.1–5 mm) in marine environments and freshwater are increasingly studied, little is known about their vector effect in wastewater treatment plants (WWTPs). Previous studies have evaluated the accumulation of antibiotic resistance genes (ARGs) on microplastics, but there is no direct evidence for the selection and horizontal transfer of ARGs on different microplastics in WWTPs. Here, we show biofilm formation as well as bacterial community and ARGs in these biofilms grown on four kinds of microplastics via incubation in the aerobic and anaerobic tanks of a WWTP. Microplastics showed differential capacities for bacteria and ARGs enrichment, differing from those of the culture environment. Furthermore, ARGs in microplastic biofilms were horizontally transferred at frequencies higher than those in water samples in both tanks. Therefore, microplastics in WWTPs can act as substrates for horizontal transfer of ARGs, potentially causing a great harm to the ecological environment and adversely affecting human health. [Display omitted] • Microplastics showed differential capacities for bacteria and ARGs enrichment. • The ARGs on microplastic biofilms can be transferred horizontally to free cells. • Microplastic biofilms performed horizontal gene transfer at frequencies higher than sludge. [ABSTRACT FROM AUTHOR]

River corridors are vital to urban ecology, regulating climate and providing habitats for animals. Spontaneous plants naturally colonize various spaces therein, where they play important roles. Previous studies have explored many factors driving spontaneous plant diversity at the city scale and in specific habitats. However, we lack a holistic understanding of the diversity and distribution of variation of spontaneous vegetation that directly reflects the effects of urbanization. We conducted a field study of 1250 sample plots along river corridors in Chengdu, a fast-growing city in China, and the spontaneous plants in fifteen microhabitat types were surveyed. Diversity and distribution patterns were examined for species with distinct dispersal abilities. There was a far greater richness of occasional species compared to dominant and common species, but occasional species were markedly less abundant. Vacant lots and natural riverbanks harbored the most species, but revetment walls and lawns also supported a considerable number of species, especially in the city center. Species diversity among different urban areas was strongly related to microhabitat conditions. The proportions of dominant, common, and occasional species varied among communities. In communities on vacant lots of less urbanized areas, the richness of dominant species was greater, whereas in green spaces created by planted vegetation, occasional species were more diverse. Green space microenvironments are hospitable to some rare species. Urbanization and microhabitats have co-effects and thus ultimately determine diversity and distribution patterns. Such patterns, if linked to ecological and ornamental value, can provide a new perspective and nature-based solutions to urban rewilding and landscape design. • A total of 336 spontaneous plants were identified along city river corridor in Chengdu, China. • Occasional species were far richer, although less abundant. • Vacant lots in urban fringe harbored the most number of species. • The city center supported considerable species in lawns and revetment walls. • The diversity of different species assemblages largely varied at community level. [ABSTRACT FROM AUTHOR]