Urban water, defined as water not used for agriculture or to support natural ecosystems, is increasingly impacted by anthropogenic pollution. Among the key concerns are emerging contaminants (ECs), a diverse group of largely unregulated chemical compounds that pose growing threats to both water and the life it supports. This review critically examines the challenges associated with the presence of ECs in urban water through two complementary approaches that together offer both scientific and policy-oriented insights. The first approach focuses on evaluating the difficulties in classifying, characterizing, detecting, monitoring, enforcing policies, and assessing the risks of ECs. The second approach focuses on assessing whether current efforts in research, public awareness, regulation, treatment, recycling, and international collaboration align with the United Nations Sustainable Development Goals (SDGs), particularly SDG 6 (clean water and sanitation), SDG 11 (sustainable cities and communities), and SDG 12 (responsible consumption and production). Current efforts to address the challenges posed by ECs and to achieve SDG targets remain insufficient, particularly in the areas of treatment and recycling. Globally, only 56% of household wastewater is treated safely, and industrial wastewater treatment in low-income countries remains severely lacking, with coverage under 30%. Globally, the effective management of ECs is hindered by outdated and inadequate treatment infrastructure, low recycling rates, and the technical complexity of handling multi-contaminant waste streams. In developing regions, these challenges are compounded by weak regulatory enforcement and limited public awareness. To effectively address ECs in urban water and fully meet the SDG targets, more integrated and globally coordinated efforts are necessary.

Difflugia australis, first described by Playfair (1918), has a unique morphotype. However, in the absence of morphometric data, it has not yet been reliably classified within the largest testate amoeba genus Difflugia. In this study D. australis collected from a subtropical reservoir in southeast China was investigated by means of light and scanning electron microscopy. Basing on biometrical data, we provide an improved diagnosis of this little known species. Difflugia australis is different from other similar congeners (i.e., D. bacillariarum Perty, 1849 and D. elegans Penard, 1890) mainly by the combination of the following features: the shell is broadly ovate, with rounded dome and convex sides converging down to a very short distance from the aperture and diverging suddenly into a short rim (collar). It is usually more or less asymmetrical, with one side being more dilated than the other. The shell surface is slightly smooth, composed of flat siliceous plates of irregular shape and size, mixed with fine grains; microbial spores of comparable forms are spread on the shell surface; particles are often interspersed with a network of organic cement with unique mesh pattern; one (sometimes two) slanting spine-like posterior end of the shell is variable in form; collar is mainly formed by small plates of equal size. The dimensions of the shell are: total shell length 88–106 µm; shell width 53–88 µm; aperture diameter 19–28 µm; collar height 3–6 µm; spine length 3‒23 μm. The size frequency distributions of both total shell length and shell width indicate that it is a size-monomorphic species with low variability.