Meriç Delta, which has a wide variety of ecosystems, is an A Class Wetland and the most significant natural stagnant freshwater ecosystem located in the south-western of Thrace Region of Türkiye. In this research, heavy metals (Cr, Ni, As, Cd, and Pb) were investigated in the surface water and Carassius gibelio (Bloch, 1782) obtained from Meriç Delta lakes (Gala, Pamuklu, Sığırcı, and Dalyan), which are located on an important migration route of water birds. The heavy metals in surface water samples and fish tissues were determined by ICP-MS. Dissolved oxygen, oxygen saturation (%), pH, electrical conductivity, total dissolved solids, nitrite nitrogen, nitrate nitrogen, and total phosphorus parameters were measured in surface waters. High total phosphorus content was detected in the investigated region. The measured As, Cr, and Ni values in water samples were determined to be higher than Türkiye Regulation Standards criteria. Fish were taken from Gala and Sığırcı Lake. The mean concentrations of measured heavy metals were found to be below permissible values in fish muscle and gill. The target hazard quotient (THQ) and total THQ values (HI) of all heavy metals did not exceed the limit value.

The Guanabara Bay hydrographic region (GBHR) has served as a central hub for human settlement and resource utilization throughout Brazil\'s history. However, the region\'s high population density and intense industrial activity have come at a cost, leading to a significant decline in water quality. This work aimed to identify homogeneous regions in GBHR according to water quality parameters in dry and rainy periods. The following water quality monitoring variables were monitored at 49 gauge stations: total phosphorus (TP), nitrate (NO3-), dissolved oxygen (DO), hydrogenionic potential (pH), turbidity (Turb), thermotolerant coliforms (TCol), total dissolved solids (TDS), biochemical oxygen demand (BOD), water temperature (Tw), and air temperature (Ta). The statistical analysis consisted of determining principal components, cluster analysis, seasonal differences, and Spearman\'s correlation. The water quality parameter correlations were not expressively influenced by seasonality, but there are differences in the concentrations of these parameters in the dry and rainy periods. In the dry period, urban pressure on water quality is mainly due to fecal coliforms. The resulting clusters delimited areas under urban, agricultural, and forestry influence. Clusters located in areas with high demographic density showed high concentrations of TCol and TP, while clusters influenced by forestry and agriculture had better water quality. In the rainy season, clusters with urban influence showed problems with TCol and TP, in addition to some characteristics in each group, such as high TDS, NO3-, and BOD. Forested areas showed high DO, and clusters under agricultural influence had higher concentrations of TCol, BOD, and NO3- concerning forested regions. The troubling state of sanitation in GBHR occurs in metropolitan regions due to lack of a formal sanitation system.

Despite the keen interest in potentially using the metal-organic framework (MOF) in advanced oxidation processes (AOPs), their application for environmental abatement and the corresponding degradation mechanisms have remained largely elusive. This study explores the use of cobalt-based MOF (CoMOF) for peroxymonosulfate (PMS) activation to remove tetracycline (TC) from water resources. Under optimal conditions, the given catalytic system could achieve a TC removal of 83.3%. Radical quenching tests and EPR analysis revealed that SO4•-, HO•, •O2-, and 1O2 could participate in the catalytic degradation, but the discernable removal mechanism was mainly ascribed to the nonradical pathway induced by 1O2. At only 5 mg/L of CoMOF, the performance of the catalytic system was superior to that of PMS alone for different types of micropollutants. The CoMOF/PMS system could also reliably deal with typical anions in water, such as Cl-, SO42-, HCO3-, and PO43-. The MOF catalyst could last for four cycles with a minor decrease in reactivity of ∼ 30%. However, the removal performance decreased markedly when aromatic natural organic matter (NOM) were present in the water bodies, and the effectiveness was lower in alkaline or acidic environments. Our work offers insights into the catalytic degradation of CoMOF/PMS applied in contaminated water remediation and serves as a baseline for fabricating an efficient MOF with enhanced catalytic performance and stability.

Soil Aquifer Treatment (SAT) is a robust technology to increase groundwater recharge and to improve reclaimed water quality. SAT reduces dissolved organic carbon, contaminants of emerging concern, nutrients, and colloidal matter, including pathogen indicators, but little is known about its ability to reduce loads of antibiotic resistance genes (ARGs) from reclaimed waters. Here we test six pilot SAT systems to eliminate various biological hazards from the secondary effluents of a wastewater treatment plant (WWTP), equipped with reactive barriers (RBs) including different sorptive materials. Using flow cytometry, qPCR and 16S rRNA gene amplicon sequencing methods, we determined that all six SAT systems reduced total loads of bacteria by 80 to 95 % and of clinically relevant ARGs by 85 to 99.9 %. These efficiencies are similar to those reported for UV/oxidation or membrane-based tertiary treatments, which require much more energy and resources. The presence and composition of reactive barriers, the season of sampling (June 2020, October 2020, and September 2021), or the flow regime (continuous versus pulsating) did not affect ARG removal efficiency, although they did alter the microbial community composition. This suggests that an adequate design of the SAT reactive barriers may significantly increase their performance. Under a mechanistic point of view, we observed an ecological succession of bacterial groups, linked to the changing physical-chemical conditions along the SAT, and likely correlated to the removal of ARGs. We concluded that SAT is as cost-efficient technology able to dramatically reduce ARG loads and other biological hazards from WWTP secondary effluents.

Humans can be exposed to multiple pollutants in the air and surface water. These environments are non-static, trans-boundary and correlated, creating a complex network, and significant challenges for research on environmental hazards, especially in real-world cancer research. This article reports on a large study (377 million people in 30 provinces of China) that evaluated the combined impact of air and surface water pollution on cancer. We formulate a spatial evaluation system and a common grading scale for co-pollution measurement, and validate assumptions that air and surface water environments are spatially connected and that cancers of different types tend to cluster in areas where these environments are poorer. We observe \"dose-response\" relationships in both the number of affected cancer types and the cancer incidence with an increase in degree of co-pollution. We estimate that 62,847 (7.4%) new cases of cancer registered in China in 2016 were attributable to air and surface water pollution, and the majority (69.7%) of these excess cases occurred in areas with the highest level of co-pollution. The findings clearly show that the environment cannot be considered as a set of separate entities. They also support the development of policies for cooperative environmental governance and disease prevention.

Microplastic (MP) contamination has become a serious environmental concern that affects terrestrial environments, aquatic ecosystems, and human health. The current study assesses the presence, abundance, and morphology of MPs present in the surface water of Rohtak district, Haryana, India, which is rapidly undergoing industrialization. While the morphological studies of MPs were conducted through stereo microscopy and field emission-scanning electron microscopy (FE-SEM), the elemental composition of polymers was analyzed through attenuated total reflectance-Fourier transform infrared (ATR-FTIR). The results revealed that the surface water was significantly contaminated by polyethylene, polypropylene, and polystyrene. Moreover, the abundance of MPs was found to be 16-28 particles/L with an average value of 23 particles/L. Most of the MPs had fibrous morphology with the specifics being, fibers (43.9%), fragments (23.7%), films (17%), and pellets (15.4%). The MPs exhibited a size range of 0.61-4.87 mm, with an average size measured at 2.03 ± 0.04 mm. Also, the MP pollution load index values for the surface water bodies were found to be below 10, indicating a low risk category. Though currently designated as \"low risk,\" it is important that mitigation strategies be brought over at this juncture to further prevent the deterioration of quality of water. Thus, this study not only intends to bring forth the impact of human activities, industrial waste, open waste dumping, and inadequate municipal waste management practices on increasing MP concentration but also highlights the sustainable alternatives and strategies to address this emerging pollutant in urban water systems. For further prevention, the implementation of stringent regulations and on-site plastic waste segregation is a critical component in preventing the disposal of plastic waste in surface water bodies. RESEARCH HIGHLIGHTS: The abundance of MPs was found to be 16-28 particles/L, with an average value of 23 particles/L. The surface water bodies in Rohtak district fall into the hazard categories of low risk with values less than 10. The overall MP concentration in water, across all five areas, based on color was in order: white/transparent (39.1%), black (15%), gray (9.1%), green (8.7%), blue (7.8%), red (7.8%), orange (6.3%), and yellow (6.1%). The dominant polymers were polyethylene (PE) (42%) and polypropylene (41%) as determined by FTIR spectroscopy.

Freshwater biodiversity conservation has received substantial attention in the scientific literature and is finally being recognized in policy frameworks such as the Global Biodiversity Framework and its associated targets for 2030. This is important progress. Nonetheless, freshwater species continue to be confronted with high levels of imperilment and widespread ecosystem degradation. An Emergency Recovery Plan (ERP) proposed in 2020 comprises six measures intended to \"bend the curve\" of freshwater biodiversity loss, if they are widely adopted and adequately supported. We review evidence suggesting that the combined intensity of persistent and emerging threats to freshwater biodiversity has become so serious that current and projected efforts to preserve, protect and restore inland-water ecosystems may be insufficient to avert substantial biodiversity losses in the coming decades. In particular, climate change, with its complex and harmful impacts, will frustrate attempts to prevent biodiversity losses from freshwater ecosystems already affected by multiple threats. Interactions among these threats will limit recovery of populations and exacerbate declines resulting in local or even global extinctions, especially among low-viability populations in degraded or fragmented ecosystems. In addition to impediments represented by climate change, we identify several other areas where the absolute scarcity of fresh water, inadequate scientific information or predictive capacity, and a widespread failure to mitigate anthropogenic stressors, are liable to set limits on the recovery of freshwater biodiversity. Implementation of the ERP rapidly and at scale through many widely dispersed local actions focused on regions of high freshwater biodiversity and intense threat, together with an intensification of ex-situ conservation efforts, will be necessary to preserve native freshwater biodiversity during an increasingly uncertain climatic future in which poorly understood, emergent and interacting threats have become more influential. But implementation of the ERP must be accompanied by measures that will improve water, energy and food security for humans - without further compromising the condition of freshwater ecosystems. Unfortunately, the inadequate political implementation of policies to arrest widely recognized environmental challenges such as climate change do not inspire confidence about the possible success of the ERP. In many parts of the world, the Anthropocene future seems certain to include extended periods with an absolute scarcity of uncontaminated surface runoff that will inevitably be appropriated by humans. Unless there is a step-change in societal awareness of - and commitment to - the conservation of freshwater biodiversity, together with necessary actions to arrest climate change, implementation of established methods for protecting freshwater biodiversity may not bend the curve enough to prevent continued ecosystem degradation and species loss.

The Ayeyarwady River Basin in Myanmar is grappling with severe environmental challenges, including soil erosion and water pollution, primarily driven by unsustainable agricultural practices. This study aims to evaluate farmers\' awareness of environmental policies and identify barriers to their effective implementation. In-depth interviews were conducted with 45 stakeholders, encompassing farmers, government officials, and researchers. The findings highlight a significant lack of policy awareness among farmers, exacerbated by socio-cultural, economic, and institutional obstacles. These barriers impede the successful application of environmental policies, perpetuating environmental degradation. The study advocates for integrative strategies that encompass education, community engagement, and adaptive policy frameworks to address these complex issues. Detailed policy implications are provided, offering insights into potential solutions for enhancing the region\'s environmental governance and sustainable development. This research contributes to understanding the critical interplay between policy awareness and ecological management, underscoring the importance of targeted interventions to mitigate environmental threats.

A portable toilet manufacturer in northwest Indiana (USA) released polyethylene microplastic (MP) pollution into a protected wetland for at least three years. To assess the loads, movement, and fate of the MPs in the wetland from this point source, water and sediment samples were collected in the fall and spring of 2021-2023. Additional samples, including sediment cores and atmospheric particulates, were collected during the summer of 2023 from select areas of the wetland. The MPs were isolated from the field samples using density separation, filtration, and chemical oxidation. Infrared and Raman spectroscopy analyses identified the MPs as polyethylene, which were quantified visually using a stereomicroscope. The numbers of MPs in 100 mL of the marsh water closest to the source ranged from several hundred to over 400,000, while the open water samples contained few microplastics. Marsh surface sediments were highly contaminated with MPs, up to 18,800 per 30.0 g dry mass (dm), compared to core samples in the lower depths (>15 cm) that contained only smaller MPs (<200 µm), numbering 0-480 per 30.0 g (dm). The wide variations in loads of MP contaminants indicate the influence of numerous factors, such as proximity to the point source pollution, weather conditions, natural matter, and pollution sinks, namely sediment deposition. As proof of concept, we demonstrated a novel remediation method using these real-world samples to effectively agglomerate and remove MPs from contaminated waters.

Watershed models of plastic export from rivers to oceans have large uncertainties, and improvements require direct measurements of riverine macroplastic (>5 mm) and microplastic (<5 mm). Also, plastic represents allochthonous carbon inputs to rivers but is rarely measured as carbon mass. We quantified plastic and organic matter within floating debris rafts and open water in an urban river. Macroplastics only occurred in debris rafts. Microplastics had higher concentrations in debris rafts relative to open water. Across sites, organic matter was positively correlated with microplastics and macroplastics. Last, carbon in plastic was 40% of the carbon mass in coarse particulate organic matter in debris rafts. Floating plastic litter accumulates with particulate organic matter in debris rafts. Plastic is an overlooked and ecological meaningful component of carbon standing stocks in urban rivers. Results will inform improved carbon budget calculation in rivers and watershed models of plastic export. PRACTITIONER POINTS: Plastic particles floating on the surface of an urban river accumulate in debris rafts compared to open water in terms of count and mass. Abundance and composition of plastic particles in debris rafts were distinct from those in open water areas. Plastic litter as units of carbon mass was in the same order of magnitude as carbon mass in course particulate organic matter. Plastic litter moves in similar ways to naturally occurring organic particles and should be measured as a part of the riverine carbon cycle.