Contamination Of Water Sources Research Articles

Characterization of low-pressure gaseous plasma radiation and its usage for inactivation of waterborne viruses

Water disinfection is a critical treatment step for removing harmful organisms from contaminated water sources. Vacuum ultra-violet (V-UV) radiation, generated by a low-pressure gaseous plasma discharge, consists of photons with high enough energy to break molecular bonds. In this work, we constructed and characterized a low-pressure capacitively coupled gaseous plasma and used it as a V-UV radiation source to inactivate MS2 bacteriophage, a surrogate for human enteric viruses. The treatment system allows for variation of gas composition inside the sample chamber and the modulation of V-UV radiation intensity. Both were used to separate the actual germicidal contribution of V-UV radiation from producing germicidal species by using virus inactivation to determine efficiency. OH* radical production was determined through the terephthalic acid chemical probe, which showed that when air was present in the sample chamber, it resulted in the highest OH* production and the best inactivation of MS2. Furthermore, we showcase that the OH* production rate was wavelength dependent and that ozone, generated by plasma treatment in the gas phase, leads to hydroxy terephthalic acid degradation, allowing us to determine better the actual OH* production rate with different treatment regimes. Lastly, by adding an OH* scavenger to the liquid, we were able to elucidate it as the primary inactivation agent in this setup while also providing evidence of its production in the bulk liquid by the transport and subsequent decomposition of the longer-lasting ozone molecule. This study demonstrates, for the first time, the applicability of low-pressure plasma radiation as a water treatment method.

HERisk and statistical clustering integrated for health risk modelling of PTEs in natural water resources for drinking and sanitary uses

Potentially toxic elements (PTEs) are well-known for exposing living organisms and humans to different levels of risk. The present study aimed to evaluate the extent of exposure to health risks sustained by the inhabitants of different suburbs across Southeastern Nigeria as a result of contaminated water sources. There are existing literatures on human health risk assessment in the study region. However, this is the first study to report a detailed breakdown of the risks faced by nine age groups in the study area. This was achieved by integrating a novel code (HERisk), statistical clustering, and water quality data. Laboratory analysis showed that the levels of PTEs (Fe2+, Ni2+, Cr3+, and Pb2+) in 53.6%, 17.8%, 3.5%, and 46% of the samples were found to be above the recommended limits. Aggregated human health risk scores for ingestion and dermal routes revealed that children aged 1 to 2 years are the most vulnerable to health hazards. According to cumulative carcinogenic health risk values (0.00E+00 to 2.41E-04), samples proximal to regions with significant human activities expose the locals to a high risk of developing cancer via ingestion. Q-mode hierarchical cluster analysis successfully validated the classification schemes used for the interpretation of the HERisk code values, captured the patterns in the dataset, and brought forth new perspectives. The comprehensive approach detailed in this study can be adopted as a framework for ongoing monitoring and assessment of water quality.

AO-SVM: a machine learning model for predicting water quality in the cauvery river

Water pollution is a significant cause of death globally, resulting in 1.8 million deaths annually due to waterborne diseases. Assessing water quality is a complex process that involves identifying contaminants in water sources and determining whether it is safe for human consumption. In this study, we utilized the Cauvery River dataset to develop a model for evaluating water quality. The aim of our research was to proficiently perform feature selection and classification tasks. We introduced a novel technique called the Aquila Optimization Support Vector Machine (AO-SVM), an advanced and effective machine learning system for predicting water quality. Here SVM is used for the classification, and the Aquila algorithm is used for optimizing SVM. The results show that the proposed method achieved a maximum accuracy rate of 96.3%, an execution time of 0.75 s, a precision of 93.9%, a recall rate of 95.1%, and an F1-Score value of 94.7%. The suggested AO-SVM model outperformed all other existing classification models regarding classification accuracy and other parameters.

Surface methodology for optimized adsorption of hazardous organic pollutant from aqueous solutions via novel magnetic metal organic framework: Kinetics, isotherm study, and DFT calculations

An efficient way to remove Janus Green B (JGB) dye from contaminated water sources is using of magnetic cerium (III) metal–organic framework (MCe-MOF). Analytical methods such as PXRD, TEM, FESEM, FT-IR, PZC, and XPS were used in the characterization of the MCe-MOF microspheres in order to assess the phase, crystallinity, shape, surface characteristics, and chemical composition of the MCe-MOF material. Impressive physical characteristics of the synthesized MCe-MOF material included a high surface area of 1340.05 m2/g. Conversely, MCe-MOF’s magnetic saturation (MS) was measured at 36.47 emu.g−1. The purpose of the study was to determine if MCe-MOF could effectively remove JGB dye from wastewater by adsorption. Adsorption settings that were studied included pH, adsorbent dose, beginning dye concentration, contact time, and temperature. The JGB electrical characteristics, reactivity, and shape were ascertained through the application of density functional theory (DFT). The placement of electrophilic and nucleophilic attack sites is in good agreement with the molecular orbitals (HOMO and LUMO) and MEP results, according to DFT. Based on the findings, MCe-MOF had a high capacity for adsorbing JGB dye, with an adsorption data fit by pseudo-second-order kinetic models and the Langmuir isotherm. It was evident from the adsorption energy of 27.8 kJ.mol−1 that chemisorption was the mode of adsorption. The optimal conditions for attaining a high adsorption capacity were found to be pH 8 and 0.02 g of MCe-MOF dose. The adsorption process of JGB dye onto MCe-MOF was seen to be spontaneous, endothermic, and random, as indicated by the temperature-dependent increases in the thermodynamic parameters ΔGo, ΔHo, and ΔSo. The adsorption process was optimized through the application of Response Surface Methodology and Box-Behnken design (RSM, BBD). The successful removal of dyes from the MCe-MOF material was made possible by these methods. While π-π bonding happens through the interaction of aromatic rings, chemisorption entails the formation of chemical interactions between the adsorbate and adsorbent. Electrostatic interactions arise from the attraction or repulsion of charges between the adsorbate and adsorbent, and pore-filling happens when the adsorbate fills the adsorbent’s pores. For the removal of JGB dye from wastewater, MCe-MOF exhibits great potential as an adsorbent because of its numerous adsorption processes and high adsorption capacity.

Exploring household water conservation methods in rural South Africa: a case of the Mbhashe and Mnquma local municipalities

Amidst the persistent drought disaster declared in 2015, the Amathole District Municipality grapples with severe water scarcity issues, particularly affecting local municipalities such as Mbhashe and Mnquma. Consequently, households in these areas confront the challenges of unreliable and contaminated water sources, prompting them to adopt water conservation measures to mitigate shortages. This study investigates the efficacy of water conservation methods among rural households in these drought-affected regions. It identifies associated challenges and potential interventions to ensure access to clean and dependable water. Employing a mixed methods approach, the study examines household water conservation practices through narrative analysis and descriptive statistics of survey data. Findings reveal that storing water in drums, containers, and tanks is the most prevalent conservation method, alongside measures like greywater reuse, lifestyle adjustments, and rainwater harvesting. With financial constraints and infrastructural limitations hindering broader adoption, the study found water conservation to be a challenge among the households as a minority (7.8%) of respondents adopted multiple water conservation strategies. In comparison, most respondents (73.6%) could only afford to practice one water conservation strategy at a time, and others (18.6%) had no conservation strategies. Drought conditions, lack of infrastructure, poverty, and attitudinal factors are primary barriers to effective water conservation. The study underscores the need for municipal-level initiatives to enhance water sources and advocates for increased investment in education, awareness campaigns, and policy interventions to address rural communities’ water scarcity challenges.

Data Mining Prior to Earth Mining: A Sustainable Approach for Mineral Exploitation

The extraction of mineral resources from the earth, in various mining forms, such as open-cast and underground mining, has significant environmental and societal consequences, both during and after mining operations. It results in habitat destruction, soil erosion, deforestation, biodiversity loss, and the release of harmful pollutants into the environment. These pollutants, including heavy metals and sulphur compounds, etc., which contaminate water sources and soil, posing a serious threat to ecosystems and human health. Despite these challenges, mining remains essential for providing raw materials to meet the needs of modern civilization, and as the global population grows, demand for minerals continues to rise, leading to increased mining operations. This intensified mining activity poses a significant threat to the planet Earth. In this context, addressing the negative effects of mining, such as mining failures, and disruptions to biodiversity, is a growing concern. Mining failures encompass a range of economic, environmental, and social consequences. A comprehensive understanding of these interrelated components is crucial for mitigating the risks and consequences associated with mining failures, as well as for developing sustainable and responsible mining practices.

One-step rapid removal of Cu(II) complexes via dual-active-site MOF catalysis with Peroxymonosulfate: Cooperative oxidation and adsorption

The removal of heavy metal complexes (HMCs) from wastewater is challenging due to their structural stability. Traditional methods require advanced oxidation processes (AOPs) for decomplexation, followed by chemical precipitation or adsorption. This study proposes a one-step approach using Co-imidazolate zeolitic framework-67 (ZIF-67) for simultaneous oxidation-decomplexation and in-situ adsorption of HMCs. The ZIF-67/peroxymonosulfate (PMS) system achieves 97.8 % removal of Cu(II)-citric acid complex (Cu-CA) in 60 mins, even under alkaline conditions, and demonstrates strong selectivity against ions like Ca, Mg, Na, and humic acid (HA). It effectively treats various contaminated water sources, achieving over 90 % removal efficiency for Cu(II) complexes such as oxalic acid (OA) and ethylenediaminetetraacetic acid (EDTA). The mechanism involves sulfate radicals (SO4•−) and singlet oxygen (1O2) for decomplexation, followed by amine groups in MOFs capturing Cu(II) ions through coordination interactions. This work offers a straightforward one-step method for HMCs contamination mitigation.

Impact of Deforestation on Water Quality in Cameroon

Purpose: The aim of the study was to analyze the impact of deforestation on water quality in Cameroon. Methodology: This study adopted a desk methodology. A desk study research design is commonly known as secondary data collection. This is basically collecting data from existing resources preferably because of its low cost advantage as compared to a field research. Our current study looked into already published studies and reports as the data was easily accessed through online journals and libraries. Findings: Deforestation in Cameroon significantly impacts water quality, as evidenced by increased sedimentation, higher pollutant levels, and elevated risks of waterborne diseases. Loss of forest cover reduces natural filtration capacities, leading to higher concentrations of contaminants in water sources. Alterations in hydrological patterns and changes in land use further exacerbate these issues, affecting water availability and aquatic habitats. Unique Contribution to Theory, Practice and Policy: Hydrological cycle theory, land use/land cover change (LU/LC) theory & ecosystem services theory may be used to anchor future studies on impact of deforestation on water quality in Cameroon. Implement land-use planning measures that prioritize the conservation and sustainable management of forest ecosystems, including protected area designation, forest restoration initiatives, and sustainable forest management practices. Develop and enforce policies that incentivize forest conservation and sustainable land management practices, such as payment for ecosystem services schemes, land-use zoning regulations, and carbon offset programs.

Adsorption of terbutaline β-agonists from wastewater by mechano-synthesized iron oxide nanoparticles modified copper (II) isonicotinate metal-organic framework

Frequent detection of terbutaline in wastewater highlights its potential risks to human health associated in the environment. Exposure to terbutaline through contaminated water sources or food chain have adverse effects to human health. This work emphasized on the removal of terbutaline from wastewater using adsorption technology. Mechanochemically synthesized [Cu(INA)2] metal-organic frameworks (MOFs) and its magnetic composite ([Cu(INA)2]-MOF@Fe3O4) are designed with higher specific surface areas and tailored features to accommodate the molecular size and structure of terbutaline. Thus, batch experiment has been conducted using the [Cu(INA)2]-MOF and [Cu(INA)2]-MOF@Fe3O4 for the terbutaline adsorption. The adsorption efficiency achieved by the MOFs was 91.8% and 99.3% for the Cu(INA)2]-MOF and [Cu(INA)2]-MOF@Fe3O4 respectively. The optimum for the adsorption study included terbutaline concentration of 40 mg/L, adsorbent dose of 5 mg/L, pH of 11, temperature of 25 °C and equilibrium time of 40 min. The kinetics and isotherms have been described by pseudo-second order and Langmuir models, while the thermodynamics revealed the exothermic and spontaneous nature of the process. The promising performance of the MOFs is manifested on the ease of regeneration and reusability, achieving adsorption efficiency of 85.0% and 94.7% by the Cu(INA)2]-MOF and [Cu(INA)2]-MOF@Fe3O4, respectively at five consecutive cycles. The higher performance of the MOFs demonstrates their excellent potentialities for the terbutaline adsorption from the aqueous solution.

Climate change, seasonality and household water security in rural Gambia: A qualitative exploration of the complex relationship between weather and water

Climate change could pose a threat to water security for many communities, particularly in settings where rainfall patterns are becoming more varied and there is higher frequency of extreme events, such as heavy rainfall and droughts. Understanding how rainfall affects water security—including water access, water quality and water use behaviours—can inform investment in more climate-resilient infrastructure and safeguard against future health risks. This study aims to explore how households in rural Gambia experienced water security in relation to seasonal rainfall patterns and extreme weather events. Data collection focused on two communities (Kiang West and Basse) with differing access to water infrastructure, within which some villages had greater access to groundwater sources, such as solar-powered boreholes, and others primarily used uncovered wells. 46 participants were interviewed in Spring 2022 using multiple qualitative methods, including in-depth interviews and transect walks. We found that people’s experience of water security and rainfall (including seasonal rainfall, drought and heavy rainfall) was complex and varied according to the primary household water source. Both dry and rainy season posed challenges to household water security in terms of quality and quantity. Households with access to more resilient infrastructure, such as solar-powered boreholes, discussed a shift in the relationship between weather and water security, where they were less vulnerable to water shortages during dry conditions compared to those using wells. However, these sources did not fully resolve water security issues, as they experienced water shortages during cloudy conditions. Extreme weather events, such as heavy rainfall, heightened perceived water issues, as these events sometimes damaged water infrastructure and contaminated water sources. Seasonal workloads, that were higher in the rainy season, also jeopardised water security, as this limited time for water collection. Increased investment in infrastructure, maintenance, water-treatment and behavioural change is required to mitigate the risks.

Risk Assessment of Emerging Contaminants in Urban and Natural Water Sources around Bloemfontein, South Africa: Implication for Environmental Sustainability

Risk Assessment of Emerging Contaminants in Urban and Natural Water Sources around Bloemfontein, South Africa: Implication for Environmental Sustainability

Gujarat’s plastic plight: unveiling characterization, abundance, and pollution index of beachside plastic pollution

Plastic pollution poses a pervasive threat to ecosystems worldwide, jeopardizing marine life, contaminating water sources, and perpetuating a global environmental crisis. Spatial and temporal distribution of beach debris was quantitatively assessed on three recreational beaches in Gujarat State, India. A total of six debris categories were recorded with a mean of 0.9 items/m2 in number and 3.62 g/m2 in weight. A total of Mean debris concentrations and weight per debris item did not vary significantly between study sites. Highest debris concentrations were observed in October 2021 at all sites. Around 90% was macro-debris (2.5–100 cm), with white and transparent colours most frequently encountered. Based on Clean Coast Index findings, all sites were categorized as "dirty". Plastic Abundance Index revealed that all sites had a very high abundance of plastics compared to other beach debris. Recreational activities on beaches, tourism, and extensive fishing can be the possible source of marine debris on Gujarat State. The findings of the current investigation is vital to understanding its pervasive environmental impact, encompassing threats to biodiversity, water quality, and ecosystems, while guiding effective policies to mitigate these repercussions on a global scale. It can be helpful to establish mitigation strategies urgently required to reduce marine debris pollution along the Gujarat Coast. It is recomanded to implement urgently needed mitigation strategies to diminish marine debris pollution along the Gujarat Coast.

Dynamic Modelling, Simulation, and Sensitive Analysis of Lead Removal in a Fixed-Bed Adsorption Column using Waste-Based Materials

Abstract This study focuses on dynamic modelling and numerical simulation of lead removal from contaminated water using a fixed-bed adsorption column packed with waste-based adsorbents. The pressing need for efficient and sustainable water treatment methods, particularly for heavy metal removal, underscores the significance of this research. Lead contamination in water sources poses severe health risks, necessitating the development of effective removal strategies. The present investigation centres on a comprehensive mathematical model that considers critical parameters, including the column’s physical dimensions, flow rate, initial lead concentration, adsorption rate constant, and adsorbent density. This model is expressed as a partial differential equation (PDE) describing the temporal and spatial evolution of lead concentration along the fixed-bed column. To solve the PDE, the method of lines, a powerful numerical technique that discretises the spatial domain and handles the resulting system of ordinary differential equations (ODEs) using an adaptive solver, is employed. Following that, the effect factors of the simulation process are evaluated by sensitive analysis approach. Simulations are conducted to elucidate the intricate dynamics of lead removal over time and column height. The numerical approach enables the prediction of lead concentration profiles within the column at various time intervals, providing crucial insights into the behavior of the adsorption process.

Elucidating the dynamics behavior of PFASs at the water and hydrophobic low-melting mixture solvents interphase

In this work, we studied the interphase dynamics of hydrophobic low-melting mixture solvents (LoMMSs) for the advanced remediation of per- and polyfluoroalkyl substances (PFASs) in wastewater systems by using classical molecular dynamics (MD) simulations. We showed the interaction between widely prevalent PFAS-specifically perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) and an innovative LoMMS composed of cineole (CIN) and linoleic acid (LNA) at equimolar ratios. Our investigations reveal that the interphase diffusion of PFASs through the LoMMS is a multi-stage process involving diffusion, interface sorption, and subsequent migration into the bulk aqueous phase. The simulations underscore a robust affinity between the PFASs molecules and the LoMMS, with the displacement of PFASs from the water interface marked by the formation of complex hydrogen-bonded networks. This intricate interplay results in a significant reorganization of water molecules, leading to potential clustering at the interface and compression of the fluid phase. These findings not only substantiate the efficacy of LoMMSs in PFASs extraction but also highlight the need to account for competitive interactions at the water interface, which could impede the absorption kinetics. By providing a detailed molecular-level narrative of the interphase capture phenomena, this study paves the way for designing efficient, low-toxicity LoMMS-based systems for the targeted removal of PFASs from contaminated water sources.

Researches on the Mobility and Toxicity of Heavy Metals from Balomir Tailings Dump – Uricani Jiu Valley

Abstract Coal mining is a vital industrial activity but often associated with negative environmental effects, including the accumulation of waste containing heavy metals in tailings dump. These heavy metals, such as lead, chromium, copper, zinc, cadmium, mercury, and others, pose significant risks to the environment and human health. The mobility of these heavy metals is a major concern, as they can be released into soil and water during rain or erosion processes, contaminating water sources and affecting aquatic and terrestrial life. These metals can be taken over by plants and eventually end up in the trophic chain, including in humans. The toxicity of heavy metals is well known, with these substances having harmful effects on human health. In this paper, the main ways of transferring heavy metals into environmental components and their spatial distribution from sterile holes to water and soil environment components. As a case study, the sterile Balomir hole, an inactive hole for about 9 years resulting from the exploitation of the hule from the Uricani mine located in the Jiu Valley.

Analysis of natural occurring radionuclide activity concentration of fish in west coast waters of Sabah, Malaysia

Abstract Fish is an important source of protein in human diets, but concerns arise due to natural radionuclide contamination in food and water sources. The study aimed to assess the concentration radionuclides activities (232Th, 238U, and 40K) in three commercial fish species from west coast waters of Sabah, Malaysia. Additionally, the annual effective dose and cancer risk for adults consuming these fish were evaluated. The concentration analysis was conducted using the inductively coupled plasma-mass spectrometer (ICP-MS) technique. The average concentration levels of radionuclide activity detected, and the annual effective dose was estimated to be much lower than UNSCEAR recommendations. The collective effective dose was estimated at 1.88 μSv y−1 for 232Th, 1.11 μSv y−1 for 238U, and 15.12 μSv y−1 for 40K. The cancer risk for adults from the annual effective dose was also found to be much lower than UNSCEAR and ICRP recommendations. Based on the study’s findings, consuming fish from west coast waters of Sabah is deemed safe. However, it is recommended to establish a long-term monitoring system for radionuclide bioaccumulation in fish to gather valuable information for assessing the potential health risks associated with radionuclides in Malaysia, particularly in the Sabah.

Investigation of Kinetic, Equilibrium, and Thermodynamic Modeling of Perfluorooctanoic Acid (PFOA) Adsorption in the Presence of Natural Organic Matter (NOM) by Dielectric Barrier Discharge Plasma-Modified Granular Activated Carbon (GAC)

Perfluorooctanoic acid (PFOA) contamination in water sources poses significant environmental and health concerns. The kinetic, equilibrium, and thermodynamic features of PFOA adsorption in the existence of natural organic matter (NOM) were thoroughly investigated in this work using granular activated carbon (GAC) modified by dielectric barrier discharge (DBD) plasma. The impacts of DBD plasma parameters on the adsorption process were systematically examined. The results demonstrated that GAC modified by DBD plasma exhibited enhanced adsorption performance for PFOA, even in the presence of NOM. The optimal condition for plasma-treated GAC was achieved with 20 min of plasma treatment time and 100 W of plasma power, resulting in 92% PFOA removal efficiency in deionized water (DIW) and 97% removal efficiency in Chao Phraya River water (CPRW). A kinetic investigation using the pseudo-first-order model (PFOM), the pseudo-second-order model (PSOM), and the Elovich model (EM) indicated that plasma treatment time and NOM presence influenced the adsorption capacity and rate constants of PFOA with the PSOM having emerged as the most fitting kinetic model. The Langmuir isotherm model indicates monolayer adsorption of PFOA on plasma-treated GAC, with higher maximum adsorption capacity while NOM is present. The Redlich–Peterson and Sips isotherm models indicated varying adsorption capacity and heterogeneity in the adsorption system. The Sips model was determined as the most fitting isotherm model. Furthermore, the favorable and spontaneous character of PFOA adsorption onto plasma-treated GAC was validated by thermodynamic analysis, with endothermic heat absorption during the process. Overall, this comprehensive investigation provides valuable insights into the adsorption characteristics of PFOA in the existence of NOM using GAC modified by DBD plasma.

Modulation of metal-organic frameworks by anionic surfactants for rapid adsorption of organic pollutants bisphenol A and chrome black T

With the accelerated development of industry, which generates large quantities of sewage discharged into the aquatic environment, serious impacts on both environmental and human health. Detecting various organic contaminants in water sources has become common, presenting huge challenges for water treatment. Metal-organic frameworks are characterized by their rich porous structures and high chemical activity, making them ideal adsorbents for removing organic pollutants from water. In this study, sodium dodecylbenzene sulfonate is added to the precursor solution of MIL-101(Cr)-Cl2 and synthesized hierarchical porous structure adsorbents MIL-SDBS-X, using hydrothermal synthesis to enhance their adsorption capacity, making efficient and rapid removal of bisphenol A(BPA) and chromium black T(EBT), two common organic pollutants in water, which MIL-SDBS-0.7 was the most effective. MIL-SDBS-0.7 exhibites great potential in the adsorption of BPA and EBT for its high adsorption capacity (260.5 mg-1·g-1 and 272.3 mg-1·g-1) and rapid adsorption (equilibrium could be achieved in 15 minutes), The findings reveal adsorption kinetics aligns with the pseudo-second-order model and the Langmuir equation best fits to study adsorption of MIL-SDBS-0.7 to BPA and EBT. Thermodynamic parameters affirm the exothermic and higher spontaneity behavior of the adsorption process. Moreover, the adsorption mechanism of MIL-SDBS-0.7 was explored, illustrating the crucial roles of effects of hydrogen bonding π-π stacking and pore filling in the adsorption of BPA and EBT. Therefore, this work not only provided a convenient strategy for the preparation of efficient and fast MIL-SDBS-0.7 hierarchical porous material but also highlighted the promising potential of synthesized absorbents as an effective adsorbent for organic pollutants in wastewater treatment and environmental remediation.

Structural Features of Styrene-Functionalized Cyclodextrin Polymers That Promote the Adsorption of Perfluoroalkyl Acids in Water.

Cross-linked β-cyclodextrin (β-CD) polymers are promising adsorbents for the removal of per- and polyfluoroalkyl substances (PFAS) from contaminated water sources, including contaminated groundwater, drinking water, and wastewater. We previously reported porous, styrene-functionalized β-cyclodextrin (StyDex) polymers derived from radical polymerization with vinyl comonomers. Because of the versatility of these polymerizations, StyDex polymer compositions are tunable, which facilitates efforts to establish structure-adsorption relationships and to discover improved materials. Here, we evaluate the material properties and PFAS adsorption of 20 StyDex derivatives with varied comonomer structure and loading, regiochemistry of styrene placement on the CD monomer, and CD size. A StyDex polymer containing N,N'-dimethylbutyl ammonium ions exhibited the most effective PFAS adsorption in batch experiments. Furthermore, a StyDex polymer containing β-CD exhibited size-selective host-guest interactions with perfluoroalkyl acids (PFAAs) and neutral contaminants in aqueous electrolyte when compared to similar polymers containing either α-CD or γ-CD. Polymers based on β-CD monomers with an average of seven styrene groups randomly positioned over the 21 available hydroxyl groups performed similarly to those based on a β-CD monomer functionalized regiospecifically at each of the seven 6' positions. The former β-CD monomer is prepared in a single step from unmodified β-CD, so the ability to use it without compromising performance demonstrates promise for developing economically competitive adsorbents. These results offered important insights into structure-adsorption properties of StyDex polymers and will inform the design of improved StyDex formulations.

Tissue distribution, migration pathways and dietary risk assessment of fungicides in pomelo orchards in South China

Fungicides are used to protect vegetables and fruits from fungal diseases. Their ubiquitous utilization has resulted in water source contamination and human health concerns. However, the occurrence of fungicides in fruits and the potential implications for human health remain unclear. In this study, ninety-five fungicides were measured in pomelo and corresponding soil and leaf samples from two pomelo orchards in South China. The mean concentration of target fungicides (∑fungicides) in pulp (honey pomelo: 0.23±0.24 ng/g; shatian pomelo: 0.23±0.11 ng/g) were much lower than those in surface soil (0.53±0.57 ng/g; 1.41±1.85 ng/g) and leaf (6.97±3.20 ng/g; 28.5±11.1 ng/g). Triazole fungicides emerged as the predominant fungicides. Varied fungicides exhibit distinct tissue distribution in fruits, demonstrating diverse migration behaviors. The distribution of all fungicides followed the order: exocarp > mesocarp > endocarp > seed > pulp. No significant associations between fungicides in both soil and pulp suggest that the primary origin of fungicides in pulp may involve external exposure. Although the dietary risks of the target fungicides in pomelo were far lower than 1, it was not negligible. Our study provides novel insights into the residues and behavior of fungicides, offering foundational data for the dietary risk assessment of pomelo consumption.