Emerging Contaminants: A Rising Threat to Urban Water and a Barrier to Achieving SDG-Aligned Planetary Protection

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 Globally, the effective management of ECs is hindered by outdated and inadequate treatment infrastructure, low recycling rates, and the technical complexity of handling multi-contaminant waste streams.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.