ACS ES&T water最新文献

The exposure of activated carbon (AC) to chlorine can produce more toxic byproducts, but their interactions and byproducts in the presence of bromide have never been investigated yet. Therefore, this work first studied the effects of AC on the disinfection byproduct (DBP) formation with bromide and free radical-mediated reaction process. The results indicated that the proportion of brominated trihalomethanes/brominated haloacetic acids in the effluent was increased by 3–10% with AC and toxicity also increased. Fourier transform ion cyclotron resonance mass spectrometry results suggested that the relative intensity of halogenated byproducts including unknown brominated DBPs (Br-DBPs) was increased by 21%. In addition, the free radical-mediated reaction activated by AC also contributed to the generation of aliphatic halogenated and nonhalogenated compounds. The chlorine and bromide free radicals were activated by the AC. Though the reactive bromide species did not lead to the Br-DBP formation, HOBr or Br₂ generated during the free radical chain reaction and the modification of the DOM properties through free radical reaction were responsible for the increase of Br-DBPs. Therefore, this study could provide a novel insight into the control of the risk of the toxic byproducts when using chlorine and AC simultaneously.

The heterogeneous photo-Fenton-like process, mediated by iron oxides and carboxylates, is recognized for its effectiveness in degrading organic pollutants. Despite its potential, the adverse effects of carboxylates on removing strongly adsorptive pollutants have not been thoroughly explored. Herein, based on a precomparison of three different micropollutants, p-arsanilic acid (ASA), a strong adsorbate, was used as a model pollutant to investigate its removal in goethite–carboxylate systems under UVA irradiation. The effects of oxalate, citrate, malate, and salicylate were assessed across varying carboxylate concentrations (0–2 mM) and goethite dosages (0.1–0.5 g·L^–1). Key findings indicate that remarkable ^•OH contribution was only observed in oxalate and citrate systems following the generation of H₂O₂. Oxalate and citrate enhanced photodegradation but inhibited adsorption, with oxalate exhibiting a stronger promotional effect. In contrast, malate and salicylate suppressed adsorption without contributing to photodegradation. Without taking into account the suppression caused by competitive adsorption, one may overestimate the degradation of strongly adsorptive pollutants through a heterogeneous photo-Fenton-like process. These results contribute to a deeper understanding of the comprehensive effects of carboxylates in heterogeneous photo-Fenton-like systems, providing insights into the optimization of environmental remediation strategies.

Perfluorooctanoic acid (PFOA) is a persistent and bioaccumulative pollutant in aquatic environments, posing a significant threat to various organisms, including microalgae. Owing to the differences in research conditions of relevant studies, there is limited knowledge regarding the evaluation of resistance performance and strategies among different freshwater microalgae when exposed to PFOA. In this study, two representative freshwater microalgae, Chlorella sp. and Microcystis aeruginosa, were selected to comprehensively explore their resistance to PFOA exposure. The results showed that Chlorella sp. exhibited superior resistance to PFOA compared to M. aeruginosa, primarily due to its higher photosynthetic efficiency and more rapid mobilization of antioxidant responses. Additionally, Chlorella sp. was capable of extracellularly degrading PFOA at low PFOA concentrations, thereby reducing the actual concentration of PFOA affecting the Chlorella cells. Furthermore, Chlorella sp. cells exhibited self-aggregation, driven by proteins in extracellular polymeric substances (EPSs), which provided protection against PFOA exposure. In contrast, the high polysaccharide content in the EPS secreted by M. aeruginosa led to increased PFOA adsorption and uptake by the cells, resulting in severe physiological effects. This study enhances the understanding of the pivotal roles played by physiological characteristics and behavioral patterns of freshwater microalgae in their resistance to PFOA.

Ensuring water security and enabling timely responses to contamination events in water distribution systems (WDSs) rely heavily on the accurate and timely localization of contamination sources. Despite advances in water quality monitoring technologies, such as continuous sensing and grab-sampling, the coverage of monitoring remains sparse in most WDSs, making it difficult to accurately pinpoint the source of contamination. This paper introduces a novel source localization methodology designed to overcome these challenges by integrating sparse continuous sensing with targeted manual grab-sampling. The proposed approach iteratively narrows down the set of probable contamination sources by applying heuristics that account for the timing and signals from sensor measurements. To further address the uncertainty inherent in source localization, the methodology generates a probabilistic distribution over potential source locations. This distribution highlights areas requiring closer attention and guides where subsequent samples should be collected, effectively reducing uncertainty in the localization process. The methodology's performance is validated through extensive analysis, demonstrating that combining fixed sensors with adaptive sampling significantly improves precision, accuracy, and localization speed, particularly in sparse sensor networks. The proposed approach advances the use of water quality sensing technology for source localization, with further research needed to optimize its effectiveness in improving WDS security and maximizing public health protection.

Ensuring water security and enabling timely responses to contamination events in water distribution systems (WDSs) rely heavily on the accurate and timely localization of contamination sources. Despite advances in water quality monitoring technologies, such as continuous sensing and grab-sampling, the coverage of monitoring remains sparse in most WDSs, making it difficult to accurately pinpoint the source of contamination. This paper introduces a novel source localization methodology designed to overcome these challenges by integrating sparse continuous sensing with targeted manual grab-sampling. The proposed approach iteratively narrows down the set of probable contamination sources by applying heuristics that account for the timing and signals from sensor measurements. To further address the uncertainty inherent in source localization, the methodology generates a probabilistic distribution over potential source locations. This distribution highlights areas requiring closer attention and guides where subsequent samples should be collected, effectively reducing uncertainty in the localization process. The methodology’s performance is validated through extensive analysis, demonstrating that combining fixed sensors with adaptive sampling significantly improves precision, accuracy, and localization speed, particularly in sparse sensor networks. The proposed approach advances the use of water quality sensing technology for source localization, with further research needed to optimize its effectiveness in improving WDS security and maximizing public health protection.

This research integrates continuous sensor and grab-sample data, using a probabilistic approach to improve accuracy and speed in source localization.

In recent years, water governance has emerged as a critical concern, presenting challenges in predicting and assessing effective governance strategies. This paper introduces the water governance prediction system, based on a fuzzy logic controller (FLC), designed to dynamically evaluate the quality of water governance. Termed the water governance performance (WGP) model, it provides a holistic perspective that includes three key components: the water governance regime (WGR), water governance structure (WGS), and contextual factors. To validate the efficacy of the model, a case study was conducted in the Zayandeh-Rud basin in Iran, covering the period from 2006 to 2019. The model’s comprehensive approach and complexity equip water managers with valuable insights for decision-making. The study confirms the model’s efficiency in delivering accurate predictions based on effective data and indicators, highlighting its practical value in water governance assessments.

Rural sewage treatment (RST) has emerged as a critical issue in the restoration of China’s environment. Unlike in urban areas, the planning and management of RST in rural settings are significantly more complex and often constrained by limited budgets. It is significant and urgent for provincial or municipal governments to identify the villages with the highest priority for RST investment. This study proposes a decision-making model to prioritize villages for RST investment, balancing economic and ecological benefits with life-cycle costs. The model was applied across 104,246 villages in Guangdong, Henan, Hunan, Shanxi, Qinghai, and Liaoning Provinces in China, and it successfully generated priority maps for each province. Results indicate that the return on investment (ROI) for the top 5% of villages in Guangdong Province reached 1.75, which is 20.3% higher than that of random investments. Furthermore, the corresponding average revenue was 6 times greater than those of randomly selected villages. The model also demonstrated strong performance in the other 5 provinces. Factor importance analysis, utilizing random forest regression models alongside SHAP methodology, reveals that population size is the most influential factor in prioritization. The decision-making model offers scientific and efficient solutions for optimizing RST investments while maximizing marginal benefits and enhancing the efficiency of ecological protection funds.

The World Health Organization proposed the Tricycle Protocol for harmonized surveillance of extended-spectrum β-lactamase-producing E. coli (ESBL-Ec) among humans, animals, and the environment. We assessed four freshwater lakes along an anthropogenic impact gradient per the environmental surveillance recommendations of the Tricycle Protocol using membrane filtration with TBX agar supplemented with ceftriaxone (TBX-CRO) and Colilert Quanti-Trays (CQT-CRO) supplemented with the same. ESBL-Ec abundance and prevalence, and ESBL-Ec to E. coli ratios were significantly higher in the two highly impacted lakes; however, in the “pristine” bird sanctuary lake, ESBL-Ec were also present. The CQT-CRO format yielded reasonable qualitative (K = 0.603) and quantitative agreement (intraclass correlation coefficient = 0.849) with the TBX-CRO format. Based on random testing of a single colony per sample, CRO performed poorly for screening the ESBL phenotype among E. coli environmental isolates. Notably, ESBL-Ec isolates were not associated with an increased number of resistance phenotypes compared with non-ESBL isolates. Instead, the number of resistance phenotypes was associated with the lake from which the sample was collected. Our experience suggests when ESBL-Ec are abundant, such as in high-burden settings, the usefulness of the phenotype as a proxy for antimicrobial resistance in the environment is greatly diminished.

Blackwater rivers are named due to their exceptionally high concentrations of chromophoric dissolved organic matter (CDOM). They are the predominant lotic ecosystem in the United States Southeastern Coastal Plain, a region experiencing some of the nation’s highest rates of development. This study assessed variability in DOM concentration and composition across forested to urbanized blackwater systems in coastal South Carolina, U.S. Dissolved organic carbon and nutrient concentrations as well as absorbance and fluorescence optical properties reveal that urban sites have lower concentrations, elemental ratios, and less complex DOM. In contrast, forested blackwater sites have concentrations an order of magnitude higher, elevated elemental ratios, and molecular size dominated by refractory terrestrial-like DOM. Urban blackwater rivers were observed to have DOM concentrations and composition more similar to brown water systems than rural blackwater systems. These findings suggest that the urbanization of blackwater ecosystems results in lower concentrations and the export of simpler, more labile DOM, potentially lowering dissolved oxygen concentrations, increasing atmospheric carbon emissions and other negative impacts. To protect blackwater systems, baseline DOM concentrations and composition must be established to decipher impacts on water quality due to naturally occurring versus anthropogenic activities and to properly assign classifications to these diverse systems across the U.S.

Dissolved organic matter (DOM) composition was examined across blackwater coastal ecosystems, revealing transformations in DOM content associated with urbanization with implications for water quality and policy.

Radium maypose a risk to aquatic organisms, such as freshwater mussels, living downstream of facilities that discharge oil and gas produced water (OGPW). Exposed freshwater mussels incorporate radium as a calcium substitute, accumulating it in their soft tissue or carbonate shell. Here, in a 25 day controlled laboratory setting, Eurynia dilatata were dosed with radium-laden Marcellus OGPW to mimic exposures that occurred in river systems downstream of the OGPW discharges. Soft tissue from dosed mussels produced distinct ²²⁶Ra activities (mean = 2.22 pCi/g) and ²²⁸Ra/²²⁸Ra isotopic signatures (mean = 0.33) when compared to control samples (0.73 pCi/g; 0.73) with a strong linear correlation with water ²²⁶Ra activities, a direct indicator of the volume of OGPW to which freshwater mussels were exposed. Shell from dosed tanks produced similar results with distinct ²²⁶Ra activities (mean = 0.16 pCi/g) and ²²⁸Ra/²²⁸Ra isotopic signatures (mean = 0.29) when compared to control samples (0.09 pCi/g; 0.54); however, no linear trend was observed, indicating adsorption mechanisms over a short duration study. Bioconcentration factors in both the tissue and shell produced a strong negative correlation (R² = 0.82; 0.80 respectively) with water ²²⁶Ra/Ca ratios indicating high calcium concentrations in OGPW may inhibit excessive radium bioaccumulation.