Urban industrialization is a major driver of water pollution, particularly through emerging contaminants that pose significant health risks for humans and ecosystems. This critical review focuses on Bangladesh’s Buriganga and Dhaleshwari rivers, which pass through highly industrialized and urban areas, analyzing contaminant types, sources, pathways, and impacts. By synthesizing data from studies published between 2005 and 2024, the paper examines pollutants such as heavy metals (e.g., Cr, Cd, Pb, Ni, Zn, Hg, As, Mn, Cu, Fe) and microplastics in water, sediments, and biota. The Buriganga River shows extreme heavy metal contamination, with surface water Cr concentrations reaching up to 167,160 μg/L, Pb up to 3830 μg/L, and Fe up to 30,000 μg/L, and sediment Cr up to 4249 μg/g, Pb up to 3312 μg/g, and Fe up to 15,435 μg/g. In contrast, the Dhaleshwari River exhibits elevated but comparatively lower heavy metal concentrations in surface water (e.g., Cr up to 3350 μg/L; Cd up to 1890 μg/L; Pb up to 1320 μg/L; Ni up to 1732 μg/L; Fe up to 6040 μg/L) and sediments (Cr up to 282 μg/g; Fe up to 14,375 μg/g). Microplastic contamination in Buriganga is widespread across water, sediments, and biota and dominated by polymers such as polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET). Industrial discharges, particularly from the textile, leather, and metal processing industries, are identified as primary sources for heavy metals and microplastics. Additional inputs from domestic waste, agricultural runoff, and municipal sewage intensify pollution, with Cr, Cd, and Pb notably frequently exceeding safety thresholds. Microplastics, originating from municipal waste and atmospheric deposition, persist in these rivers, posing ecological and public health risks. The persistence and bioaccumulation of heavy metals and microplastics threaten aquatic biodiversity by disrupting food chains and pose significant risks to local communities that depend on these rivers for agriculture, fishing, and daily water use. This review highlights the urgent need for comprehensive bioaccumulation studies, long-term monitoring, and enhanced detection techniques to better assess contamination levels. Strengthening environmental regulations, improving waste management, and adopting sustainable industrial practices are critical to mitigating emerging contaminant impacts and safeguarding these vital river ecosystems and public health.

Per- and polyfluoroalkyl substances (PFAS) are artificial chemicals in diverse consumer and industrial goods. They are known for their enduring presence in the environment and the potential risks they pose to human health. This meta-analysis scrutinizes the sources, occurrence, fate, exposure pathways, and regulatory frameworks of PFAS globally, spanning 2021 to 2024. Through a comprehensive review of literature and regulatory documents, this study integrates the evolving trends and prevailing concerns and identifies research gaps. The analysis also reveals a need for a more regulatory landscape characterized by diverse approaches across different regions, with variations in standards, monitoring protocols, and remediation strategies. Despite concerted efforts to mitigate PFAS contamination, significant challenges persist, including regulatory inconsistencies, limited data availability, and emerging PFAS variants not covered by existing regulations. Sources of PFAS contamination encompass a broad spectrum of industrial activities, consumer products, and legacy pollution, with emerging evidence highlighting the role of atmospheric transport in global dispersion. Moreover, PFAS persistence in the environment and their bioaccumulative nature portray the urgency of understanding fate and transport mechanisms across various environmental compartments. Exposure pathways to PFAS exhibit multifaceted routes with humans, animals, invertebrates, and biota. Furthermore, disparities in exposure patterns are evident across different geographic regions and demographic groups, accentuating the need for targeted interventions and risk mitigation strategies. This meta-analysis identifies critical research needs, including enhanced surveillance programs, standardized methodologies, and interdisciplinary approaches to address PFAS contamination’s complexities comprehensively. This study provides a holistic overview of PFAS regulatory frameworks, sources, occurrence, fate, and exposure around the globe, highlighting evolving trends, persistent concerns, and crucial knowledge gaps. By synthesizing current knowledge and identifying research priorities, this study aims to inform policy development, regulatory enforcement, and scientific endeavors to address the challenges posed by PFAS contamination effectively.

Urbanization, agriculture, and tides collectively influence nutrient dynamics in river-estuary continua, yet their relative contributions remain difficult to disentangle. We integrated 25 years (1999-2024) of hydrologic, salinity, and water-quality data of the St. Johns River (Florida, USA) with flow-normalized Weighted Regressions on Time, Discharge, and Season (WRTDS) and its tidal adaptation (WRTDStidal) to characterize long-term trends in total Kjeldahl nitrogen (TKN), total nitrogen (TN), and total phosphorus (TP) across four representative HUC-12 subwatersheds (Rockledge headwaters, Sanford mid-basin, Cow Creek agricultural tributary, and Jacksonville estuarine outlet) that spanned headwaters to estuary. Flow-normalized nutrient trends were spatially heterogeneous: Rockledge and Cow Creek showed increasing TKN, Sanford declined, and Jacksonville showed sustained decreases; TP declined at all four sites. TN responses were mixed and diverged from TKN at Cow Creek, where model uncertainty was also greatest. WRTDStidal results showed lower modeled nutrient concentrations under stronger marine influence, particularly downstream, consistent with mixing-related modulation but not unique process attribution. County-level population growth and HUC-12 septic-system density did not correspond uniformly with nutrient trajectories, reinforcing a non-causal interpretation of watershed-pressure indicators. Given the small number of subwatersheds (N = 4), land-cover, population, septic, correlation, and PCA results are treated as exploratory context; integrating flow and tidal normalization provides complementary views of nutrient change in tidally influenced watersheds. These findings describe longitudinal nutrient contrasts and motivate testable hypotheses about potential source and processing mechanisms along a freshwater-marine continuum.