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Nano-enabled consumer materials could degrade during their use or end-of-life disposal due to weathering. Understanding the potential risks from the release and the toxicity of embedded nanomaterial is needed.

Copper-based pesticides and wood preservatives could end up in the environment during production, use, and end-of-life via different pathways that could cause unintended ecological and adverse health effects. This paper provides the effect of colloid-size Cu-based pesticides (CuPRO and Kocide), micronized Cu azole (MCA-1 and MCA-2) and alkaline Cu quaternary (ACQ) treated woods, Cu(2+), Cu(2+) spiked untreated wood (UTW), and CuCO(3) solutions against Gram-positive Bacillus species using five-day biochemical oxygen demand (BOD(5)) standard test. The total Cu leached from MCA-1, MCA-2, and ACQ in Milli-Q water after 5 days were ˜0.1, ˜0.11, and ˜0.64 g/kg of wood, respectively. However, the form of Cu leached from MCA woods was mostly ionic (> 90%). The total organic carbon (TOC) content of any tested wood (UTW/MCA-1/MCA-2/ACQ) was ˜99% of its corresponding total carbon (TC) content, whereas the TOC of any tested wood sawdust exceeded that of its corresponding piece/block by > 300%. The dissolved oxygen (DO) consumption value in the presence of Cu(2+), CuCO(3), CuPRO, and Kocide solutions was significantly influenced by Cu particles/ions. However, the DO consumption value in the presence of UTW/MCA-1/MCA-2/ACQ woods was significantly influenced by organics leached from woods. On the other hand, the DO consumption of MCA sawdust was greater than (300%) that of MCA pieces/block. The findings of this study provide more insight into how organics leached from woods significantly reduce the toxic effects of Cu ions against Gram-positive Bacillus species.

This paper reviews the currently used pretreatment methods for microplastics (MPs) analysis in soil and freshwater sediments, primarily sample processing, pretreatment, and characterization methods for MPs analysis. In addition, analytical tools (e.g., lab instruments), MPs characteristics, and MPs quantity, are included in this review. Prior to pretreatment, soil and sediment samples are typically processed using sieving and drying methods, and a sample quantity of

The increasing prevalence of products that incorporate engineered nanoparticles (ENPs) has prompted efforts to investigate the potential release, environmental fate, and exposure of the ENPs. However, the investigation of cerium dioxide nanoparticles (CeO2 NPs) in soil has remained limited, owing to the analytical challenge from the soil's complex nature. In this study, this challenge was overcome by applying a novel single particle-inductively coupled plasma-mass spectrometry (SP-ICP-MS) methodology to detect CeO2 NPs extracted from soil, utilizing tetrasodium pyrophosphate (TSPP) aqueous solution as an extractant. This method is highly sensitive for determining CeO2 NPs in soil, with detection limits of size and concentration of 15 nm and 194 NPs mL-1, respectively. Extraction efficiency was sufficient in the tested TSPP concentration range from 1 mM to 10 mM at a soil-to-extractant ratio 1:100 (g mL-1) for the extraction of CeO2 NPs from the soil spiked with CeO2 NPs. The aging study demonstrated that particle size, size distribution, and particle concentration underwent no significant change in the aged soils for a short period of one month. This study showed an efficient method capable of extracting and accurately determining CeO2 NPs in soil matrices. The method can serve as a useful tool for nanoparticle analysis in routine soil tests and soil research.

A spectrum of plastics has been produced in the last 70 years, and plastic production has increased faster than any other manufactured material. Current recycling of all plastic materials is pegged at 10% or less. The social value that plastics enjoys is reflected in its myriad uses for engineered durability to single-use applications. Disposable or single-use plastic items have become a significant problem. Plastic debris has become ubiquitous to the landscape and aquatic resources, leading to human health, ecological concerns, and sustainability issues. Past disposal practices relied on waste plastic flows to certain countries for disposal, but these have been summarily curtailed, needing alternatives as productive and environmentally conscious recycling technology. Waste plastics can be repurposed using purification, decomposition, or conversion processes that are based on established and emerging mechanical and chemical technologies. Plastic recycling technologies, such as thermal, chemical, and biological depolymerization processes, including pyrolytic technologies using plastics-to-fuel strategies, are under development ranging from bench-scale demonstrations to full-scale implementation. The ideal of closed supply chain constraints offers optimal solutions to plastic recycling. Evaluation of new processes requires performance assessment to understand better how plastics recycling technologies contribute to the environment and the sustainable reuse of plastic materials.

The increasing use of engineered nanoparticles (ENPs) in many industries has generated significant research interest regarding their impact on the environment and human health. The major routes of ENPs to enter the human body are inhalation, skin contact, and ingestion. Following ingestion, ENPs have a long contact time in the human stomach. Hence, it is essential to know the fate of the ENPs under gastric conditions. This study aims to investigate the fate of the widely used nanoparticles Ag-NP, Au-NP, CeO2-NP, and ZnO-NP in simulated gastric fluid (SGF) under different conditions through the application of single-particle inductively coupled plasma-mass spectrometry (SP-ICP-MS). The resulting analytical methods have size detection limits for Ag-NP, Au-NP, ZnO-NP, and CeO2-NP from 15 to 35 nm, and the particle concentration detection limit is 135 particles/mL. Metal ions corresponding to the ENPs of interest were detected simultaneously with detection limits from 0.02 to 0.1 μg/L. The results showed that ZnO-NPs dissolved completely and rapidly in SGF, whereas Au-NPs and CeO2-NPs showed apparent aggregation and did not dissolve significantly. Both aggregation and dissolution were observed in Ag-NP samples following exposure to SGF. The size distributions and concentrations of ENPs were affected by the original ENP concentration, ENP size, the contact time in SGF, and temperature. This work represents a significant advancement in the understanding of ENP characteristics under gastric conditions.

Nowadays, particulate matter and total volatile organic compounds in the air are the primary environmental concern of the world due to their health impact. Therefore, the present work was focused o...

This study was undertaken to assess indoor air pollution and potential exposure to particulate matters (PMs-PM1, PM2.5, PM4, PM7, PM10), and total suspended particles [TSP] and total volatile organic compounds [TVOCs] during baking of Ethiopian traditional staple food, Injera using different types of stoves at Addis Ababa, Ethiopia. The geometric mean (GOM) of PMs pollutant using clean, improved, and traditional stoves were ranged 10.8-235, 23.6-462, and 36.4-591 µg/m3, respectively. The GOM of TVOCs in the wet and dry season using the clean, improved, and traditional stoves were 1,553, 2,234, 4,421, and 845, 1,214, and 2,662 µg/m3, respectively. The health risk of an exposed person to PM2.5, PM10, and TSP during baking of Injera was characterized and the results showed only baking of Injera using any of the stove types does not cause health problems to the baker. However, the percent contribution to the total chronic intake is high up to 38%.

This study was aimed to analyze trace elements in the particulate matter-10 and evaluate their health risks during the cooking of the most widely consumed Ethiopian traditional dish sauces (Wots) u...

In recent years, an increasing number of polymeric composites incorporating engineered nanomaterials (ENMs) have reached the market. Such nano-enabled products (NEPs) present enhanced performance through improved mechanical, thermal, UV protection, electrical, and gas barrier properties. However, little is known about how environmental weathering impacts ENM release, especially for high-tonnage NEPs like kaolin products, which have not been extensively examined by the scientific community. Here we study the simulated environmental weathering of different polymeric nanocomposites (epoxy, polyamide, polypropylene) filled with organic (multiwalled carbon nanotube, graphene, carbon black) and inorganic (WS2, SiO2, kaolin, Fe2O3, Cu-phthalocyanines) ENMs. Multiple techniques were employed by researchers at three laboratories to extensively evaluate the effect of weathering: ultraviolet-visible spectroscopy (UV-vis), Fourier transform infrared spectroscopy (FTIR), optical microscopy, contact angle measurements, gravimetric analysis, analytical ultracentrifugation (AUC), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Raman spectroscopy. This work aimed to elucidate the extent to which weathering protocol (i.e. wet vs. dry) and diverse filler characteristics modulate fragment release and polymer matrix degradation. In doing so, it expanded the established NanoRelease protocol, previously used for analyzing fragment emission, by evaluating two significant additions: (1) simulated weathering with rain events and (2) fractionation of sample leachate prior to analysis. Comparing different composite materials and protocols demonstrated that the polymer matrix is the most significant factor in NEP aging. Wet weathering is more realistic than dry weathering, but dry weathering seems to provide a more controlled release of material over wet. Wet weathering studies could be complicated by leaching, and the addition of a fractionation step can improve the quality of UV-vis measurements.

The biodesalination potential at different levels of salinity of Phormidium keutzingianum (P. keutzingianum) was investigated. A wide range of salinity from brackish to hypersaline water was explored in this study to ensure the adaptability of P. keutzingianum in extreme stress conditions. Brackish to hypersaline salt solutions were tested at selected NaCl concentrations 10, 30, 50, and 70 g.L

Particulate matter with aerodynamic diameters

The intensive use of Cu-based pesticides in agriculture could have an unintended impact on the ecosystems and human health via different exposure pathways. This paper presents the results of experiments involving colloidal stability, aggregation, and dissolution of Cu(2)O commercial pesticide under various environmental conditions in view of ecological implications. The investigated pesticide contains ~750 g kg(−1) Cu (75% weight of product), Cu(2)O particles with sizes < 1 μm, and nominal size fraction of Cu(2)O nanoparticles. The co-presence of Ca(2+) (20 mM) and humic acid (HA, 15 mg L(−1)) significantly modulates (p < 0.001) the colloidal stability and mobility of particles. The dissolution of Cu at pH 5.5 was about 85%, 90%, and 75% weight more than the dissolution of Cu at pH 7.0, pH 8.5, and pH 7.0 and pH 8.5 combined, respectively in all dispersions. However, increasing HA content from 0 to 15 mg L(−1) reduced the dissolution of Cu by 56%, 50%, and 40% weight at pH 5.5, 7.0, and 8.5, respectively. Thus, pH below 7.0 is a critical factor to control the dissolution and bioavailability of Cu that may pose ecotoxicity and environmental pollution, whereas pH above 7.0 and the presence of HA attenuate the pH effect. These findings provide insight into how the potential mobility and bioavailability of Cu is modulated by the water chemistry under various environmental scenarios and media.

A total of 45 households were selected to participate in a study to assess indoor exposure to particulate matter (PM) and total volatile organic compounds (TVOC) while cooking a widely consumed Eth...

The dissemination of multi-drug resistant (MDR) superbugs in hospital environments, communities and food animals and the very dynamic bacterial mutation frequency require the development of prolonged therapeutic strategies to gain mastery over antibiotic resistance. A AuNP-lysozyme nanoantibacterial was fabricated by the conjugation of AuNPs-C6H4-4-COOH with lysozyme via green reduction of aryldiazonium gold(iii) salt [HOOC-4-C6H4N[triple bond, length as m-dash]N]AuCl4. Results from molecular docking calculations aimed at revealing the binding mode of benzoic acid with the lysozyme structure clearly showed the lowest energy conformation with benzoic acid bound in the deep buried hydrophobic cavity of the protein active site through strong hydrogen bonding and hydrophobic interactions, thus validating the experimental outcomes of the current study which also exhibited the binding of -COOH functional groups in the interior of the protein structure. The superiority of the lysozyme bioconjugate against superbugs was demonstrated by the enhanced and broadened lysozyme antibacterial activities of 98-99% against extended spectrum beta lactamase (ESBL) producing Escherichia coli and imipenem-resistant Pseudomonas aeruginosa clinical isolates and a selection of Gram-negative and Gram-positive standard ATCC strains. Selective toxicity against bacteria was confirmed by the high viability of HeLa and fibroblast cell lines and the outstanding hemocompatibility at the minimum bacterial inhibitory concentrations (MICs). Turbidimetric enzyme kinetic assay showed the enhancement of the lysozyme hydrolytic activity by gold nanoparticles on the Micrococcus lysodeikticus bacterial substrate. Using gel electrophoresis, the induced cell wall breakdown was confirmed by detecting the leaked-out bacterial genomic DNA. The integrity and morphology changes of the E. coli bacteria were investigated using a scanning electron microscope after one hour of contact with the lysozyme-gold bioconjugate. The antibacterial functionalities showed little or no damage to healthy human cells and can be applied to wound dressings and medical devices.

We report the synthesis of aryldiazonium tetrachloroaurate(III) salts [X-4-C6H4N≡N]AuCl4 (X = F, Cl, Br, I, CN, NO2) and their mild reduction to covalently functionalized nanoparticles. The synthesis of the salts was carried out by the oxidation of anilines, dissolved in HCl, using sodium nitrite followed by the exchange of the counter anion with [AuCl4]- in water. In another procedure, the anilines were protonated with H[AuCl4] in acetonitrile followed by one-electron oxidation using nitrosonium salt [NO]X (X = BF4−, PF6−). Raman and ATR-FTIR spectroscopy displayed the diazonium νN≡N and Raman showed the tetrachloroaurate νAu-Cl stretching frequencies. X-ray crystal structure of [NO2-4-C6H4N≡N]AuCl4 salt showed N≡N bond distance typical of a triple bond. Gold-aryl nanoparticles were constructed by the mild chemical reduction of the diazonium gold(III) salts using 9-borabicyclo[3.3.1]nonane (9-BBN). Nanoparticles hydrodynamic diameter, elemental composition, dynamics information, and stability data were determined. Transmission electron microscopy (TEM) measurements showed limited aggregation due to the small suppressing organic shell. However, dynamic light scattering (DLS) measurements showed considerable aggregation in acetonitrile. X-ray photoelectron spectrometry (XPS) showed the gold core in zero oxidation state and manifested the gold-organic shell connectivity. The –N=N-aryl interfacial formation on the gold surface can be ruled out since the N1s peak assigned to the diazonium moiety showed no sign in the XPS nitrogen area in addition to its absence in the ATR-FTIR spectra. Raman spectroscopy measurements showed a peak assigned to gold-carbon bonding supported by density functional calculations (DFT) on Au20-C6H4-CN model.

There is a tremendous interest in the fabrication of novel hemocompatible nanoparticles for applications in theranostics. In this context, bovine serum albumin (BSA) conjugates with the water-soluble and super robust gold-aryl nanoparticles truncated with carboxylic functionals were synthesized. The gold-aryl nanoparticles were fabricated by the mild reduction of the diazonium gold(III) salt [HOOC-4-C6H4N≡N]AuCl4. The gold core size and the presence of BSA sheath encapsulating Au−COOH nanoparticles were concluded from transmission electron microscopy (TEM). Clear spectral changes supported by quantitative X-ray photoelectron spectrometry (XPS) surface analysis are visible: the C1s/Au4d intensity ratio increased sharply and the gold features were very well attenuated after BSA attachment, which brings more nitrogen essentially due to NH-C = O peptide links. The conjugation of BSA with Au−COOH nanoparticles resulted in the isoelectric point (pI) change from 4.7 to a range of 4.1-5.0. The robustness of the bioconjugates can be concluded based on the high ζ-potential values and the resistance to drastic pH conditions. The high encapsulation efficiency percentage (EE%) calculated using Bradford protein assay was in a range of 90.0–94.6% under physiological pH values. Taken together, overall studies imply the presence of interaction between the Au−COOH nanoparticles and BSA. In this study we investigated the interaction of gold nanoparticles and their BSA conjugates with human red blood cells (RBCs), which might cause cell deformity and hemolysis. To elaborate on the uniqueness of the bioconjugates, they showed negligible hemolysis or morphology deformation to cells membrane visualized using light and phase contrast microscopes. Quantitative measurements of hemoglobin leached out of the cell membrane using UV–vis showed negligible hemolysis. The high physiological stability of the conjugates fosters their applications in intravenous drug delivery supported by the long blood circulation half-life.

Achieving sustainable agricultural productivity and global food security are two of the biggest challenges of the new millennium. Addressing these challenges requires innovative technologies that can uplift global food production, while minimizing collateral environmental damage and preserving the resilience of agroecosystems against a rapidly changing climate. Nanomaterials with the ability to encapsulate and deliver pesticidal active ingredients (AIs) in a responsive (for example, controlled, targeted and synchronized) manner offer new opportunities to increase pesticidal efficacy and efficiency when compared with conventional pesticides. Here, we provide a comprehensive analysis of the key properties of nanopesticides in controlling agricultural pests for crop enhancement compared with their non-nanoscale analogues. Our analysis shows that when compared with non-nanoscale pesticides, the overall efficacy of nanopesticides against target organisms is 31.5% higher, including an 18.9% increased efficacy in field trials. Notably, the toxicity of nanopesticides toward non-target organisms is 43.1% lower, highlighting a decrease in collateral damage to the environment. The premature loss of AIs prior to reaching target organisms is reduced by 41.4%, paired with a 22.1% lower leaching potential of AIs in soils. Nanopesticides also render other benefits, including enhanced foliar adhesion, improved crop yield and quality, and a responsive nanoscale delivery platform of AIs to mitigate various pressing biotic and abiotic stresses (for example, heat, drought and salinity). Nonetheless, the uncertainties associated with the adverse effects of some nanopesticides are not well-understood, requiring further investigations. Overall, our findings show that nanopesticides are potentially more efficient, sustainable and resilient with lower adverse environmental impacts than their conventional analogues. These benefits, if harnessed appropriately, can promote higher crop yields and thus contribute towards sustainable agriculture and global food security.

The increasing prevalence of products that incorporate engineered nanoparticles (ENPs) has prompted efforts to investigate the potential release, environmental fate, and exposure of the ENPs. However, the investigation of cerium dioxide nanoparticles (CeO(2) NPs) in soil has remained limited, owing to the analytical challenge from the soil’s complex nature. In this study, this challenge was overcome by applying a novel single particle-inductively coupled plasma-mass spectrometry (SP-ICP-MS) methodology to detect CeO(2) NPs extracted from soil, utilizing tetrasodium pyrophosphate (TSPP) aqueous solution as an extractant. This method is highly sensitive for determining CeO(2) NPs in soil, with detection limits of size and concentration of 15 nm and 194 NPs mL(−1), respectively. Extraction efficiency was sufficient in the tested TSPP concentration range from 1 mM to 10 mM at a soil-to-extractant ratio 1:100 (g mL(−1)) for the extraction of CeO(2) NPs from the soil spiked with CeO(2) NPs. The aging study demonstrated that particle size, size distribution, and particle concentration underwent no significant change in the aged soils for a short period of one month. This study showed an efficient method capable of extracting and accurately determining CeO(2) NPs in soil matrices. The method can serve as a useful tool for nanoparticle analysis in routine soil tests and soil research.

Per- and polyfluoroalkyl substances (PFAS) are a large group of perfluorinated organic molecules that have been in use since the 1940s for industrial, commercial, and consumer applications. PFAS are a growing concern because some of them have shown persistent, bioaccumulative and toxic effects. Herein, we demonstrate an innovative technology of UV-vis/Zn

The increasing use of engineered nanoparticles (ENPs) in many industries has generated significant research interest regarding their impact on the environment and human health. The major routes of ENPs to enter the human body are inhalation, skin contact, and ingestion. Following ingestion, ENPs have a long contact time in the human stomach. Hence, it is essential to know the fate of the ENPs under gastric conditions. This study aims to investigate the fate of the widely used nanoparticles Ag-NP, Au-NP, CeO(2)-NP, and ZnO-NP in simulated gastric fluid (SGF) under different conditions through the application of single-particle inductively coupled plasma-mass spectrometry (SP-ICP-MS). The resulting analytical methods have size detection limits for Ag-NP, Au-NP, ZnO-NP, and CeO(2)-NP from 15 to 35 nm, and the particle concentration detection limit is 135 particles/mL. Metal ions corresponding to the ENPs of interest were detected simultaneously with detection limits from 0.02 to 0.1 μg/L. The results showed that ZnO-NPs dissolved completely and rapidly in SGF, whereas Au-NPs and CeO(2)-NPs showed apparent aggregation and did not dissolve significantly. Both aggregation and dissolution were observed in Ag-NP samples following exposure to SGF. The size distributions and concentrations of ENPs were affected by the original ENP concentration, ENP size, the contact time in SGF, and temperature. This work represents a significant advancement in the understanding of ENP characteristics under gastric conditions.

In this paper, the application of biofiltration is investigated for controlled removal of gas phase chloroform through cometabolic degradation with ethanol. A trickle bed air biofilter (TBAB) operated under acidic pH 4 is subjected to aerobic biodegradation of chloroform and ethanol. The TBAB is composed of pelleted diatomaceous earth filter media inoculated with filamentous fungi species, which served as the principle biodegrading microorganism. The removal efficiencies of 5 ppm(v) of chloroform mixed with different ratios of ethanol as cometabolite (25, 50, 100, 150, and 200 ppm(v)) ranged between 69.9 and 80.9%. The removal efficiency, reaction rate kinetics, and the elimination capacity increased proportionately with an increase in the cometabolite concentration. The carbon recovery from the TBAB amounted to 69.6% of the total carbon input. It is postulated that the remaining carbon contributed to excess biomass yield within the system. Biomass control strategies such as starvation and stagnation were employed at different phases of the experiment. The chloroform removal kinetics provided a maximum reaction rate constant of 0.0018 s(−1). The highest ratio of chemical oxygen demand (COD)(removal)/nitrogen(utilization) was observed at 14.5. This study provides significant evidence that the biodegradation of a highly chlorinated methane can be favored by cometabolism in a fungi-based TBAB.

There is a lack of field compatible analytical method for the speciation of As(III) to characterize groundwater pollution at anthropogenic sites. To address this issue, an inhibition-based acetylcholine esterase (AchE) sensor was developed to determine As(III) in groundwater. 4-Acetoxyphenol was employed to develop an amperometric assay for AchE activity. This assay was used to guide the fabrication of an AchE sensor with screen-printed carbon electrode. An As(III) determination protocol was developed based on the pseudo-irreversible inhibition mechanism. The analysis has a dynamic range of 2-500 μM (150 – 37,500 μg L(−1)) for As(III). The sensor exhibited the same dynamic range and sensitivity in a synthetic groundwater matrix. The electrode was stable for at least 150 days at 22 ± 2 °C.

People living in urban areas face different air-pollution-related health problems. Commuting is one of the high-exposure periods among various daily activities, especially in high-vehicle-congestion metropolitan areas. The aim of this work was to investigate the commuter exposure assessment to particulate matters with different aerodynamic diameter (

The degradation of polypropylene (PP) and PP-multiwalled carbon nanotube (PP-MWCNT) panels during environmental weathering resulted in an increased degree of crystallinity, making them brittle, and creating surface cracks. The degradation led to a breakdown of the panels and increased the potential for nanorelease. Thermal analysis revealed that the thickness of the test panels and reinforcement with MWCNTs had a significant influence on the stability of PP-MWCNT composites. Differential scanning calorimetry indicated that the MWCNTs acted as nucleation points, increasing the crystallization temperatures of PP-MWCNT, which reduced the extent of aging. Weathering decreased both the melting and crystallization temperatures of PP by as much as 20 °C. The reduction in the temperatures was inversely proportional to the thickness of the panels. The activation energy (Ea) obtained using isoconversional kinetics of the TGA analysis showed that the effective thermo-oxidative degradations of PP changed during aging. The Ea for the initial stages of thermal degradation decreased from ∼330 kJ/mol to ∼100 kJ/mol for aged PP. During the late degradation stages, the Ea values increased to ∼300 kJ/mol. These results suggest that early degradation were altered because of the changes in the molecular structure of the aged PP and a shift in the degradation rate-limiting steps.

Algae is an appropriate natural resource to augment the optimal use of undesired ions in water and wastewater. Increasing algal cells, the consumption of particular ions, including chloride, nitrate, phosphate, and ammonium, provides a suitable way to optimize water treatment processes. Different algal species have the capability to survive in extreme salinities by developing resistance against osmotic pressure in saline water. The current study reviews the effect of salinity on algal biomass production, algal growth rate, chlorides, nitrates, phosphates, chemical oxygen demand (COD), total nitrogen, total phosphorus, and ammonium ions. Mainly algae cultivated in freshwater, synthetic brackish water, seawater, and hypersaline water, were studied for this review. Various ion uptake mechanisms used by the algal cell are summarized, focusing on biosorption and bioaccumulation processes. Critical parameters such as light intensity, pH, and temperature variations significantly influence ion and nutrients uptake efficiencies. Analysis performed on collected data indicated that halophytic algae could survive in high salinities at elevated growth rates compared to freshwater. The halotolerant algal species showed an inclining trend of chloride ion removal with an elimination capacity of 7.5 g.m−3.h−1. Moreover, the nitrate uptake rate in halophytic algae is 10-folds higher to phosphate, regardless of salinity level. It could be concluded that microalgae will be beneficial for ion and nutrient uptake processes in treating high saline water.

Natural organic matter (NOM) affects the stability and transport of nanoparticles (NPs) in natural waters by modifying their physiochemical properties. Source location, and seasonal variations, influence their molecular, physical and electrical charge properties. To understand the variations of NOM on the mobilization of NPs, large volumes of water were collected from the Ohio River (OR) over winter and summer seasons and dissolved NOMs were concentrated. The chemical and structural differences of these NOMs were compared with the Suwannee River humic acid (SRHA) SRHA using 1H and 13C nuclear magnetic resonance spectroscopy, and Fourier transforms infrared (FTIR) spectroscopy. Thermal analysis and FTIR confirmed that differences in composition, structure, and functional groups are a result of SRHA fractionation compared to whole molecule OR-NOM. The influence of OR-NOMs on the surface charge of CeO2 NPs and the effects on the transport and retention in a three-phase (deposition-rinse-re-entrainment) sand-packed columns were investigated at CeO2 NPs initial concertation of 10ppm, pH6.8, increasing ionic strength (3, 5, and 10mM), retention time of 1min, and increasing NOM concentration (1, 5, and 10ppm). The summer OR-NOM showed higher stabilization and mobilization effect on the CeO2 than the winter NOM; while their effect was very different form the SRHA. The stabilization of NPs is attributed to both electrostatic and steric effects. The differences in the chemical structure of the complex and heterogeneous NOMs showed disparate reactivity and direct impact on CeO2-NPs stability. Using SRHA to study the effect of NOM for drinking water related assessment does not sufficiently represent the natural conditions of the environment.

Per- and polyfluoroalkyl substances (PFAS) are a large group of perfluorinated organic molecules that have been in use since the 1940s for industrial, commercial, and consumer applications. PFAS are a growing concern because some of them have shown persistent, bioaccumulative and toxic effects. Herein, we demonstrate an innovative technology of UV–vis/ZnxCu1-xFe2O4/oxalic acid for the degradation of perfluorooctanoic acid (PFOA) in water. The magnetically retrievable nanocrystalline heterogeneous ferrite catalysts, ZnxCu1-xFe2O4 were synthesized using a sol-gel auto-combustion process followed by calcination at 400 °C. The combination of ZnxCu1-xFe2O4 and oxalic acid generate reactive species under UV light irradiation. These reactive species are then shown to be capable of the photodegradation of PFOA. The degree of degradation is tracked by identifying transformation products using liquid chromatography coupled with quadrupole time-of-flight mass spectroscopy (LC-QTOF-MS).

In this study, the biodegradation of a mixture of two trihalomethane (THM) compounds, chloroform (CF) and dichlorobromomethane (DCBM), was evaluated using two laboratory-scale biotrickling filters (BTFs). The two BTFs, hereby designated as “BTF-A” and “BTF-B,” were run parallel and used ethanol as co-metabolite at different loading rates (LRs), and a lipopeptide-type biosurfactant that was generated by the gram-positive bacteria, Surfactin, respectively. The results using BTF-A showed that adding ethanol at a higher rate of 4.59 g/(m(3) h) resulted in removal efficiencies of 85% and 87% for CF and DCBM, respectively. Conversely, for the same LR, the use of Surfactin without ethanol (BTF-B) showed comparable removal efficiencies of 85% and 80% for CF and DCBM, respectively. The maximum rate constant for CF and DCBM for the BTF-A was 0.00203 s(−1) and 0.0022 s(−1), respectively. For the same THMs LR, similar reaction rate constants resulted for the BTF-B. Further studies were conducted to investigate and understand the microbial diversity within both BTFs. The result indicated that for BTF with co-metabolite, Fusarium sp. was the most dominant fungi over 98% followed by F. Solani with less than 2%. F. oxysporum and Fusarium sp. were instead the dominant fungi for the BTF with Surfactin. Before introducing the Surfactin into the BTF, the batch experiment was conducted to evaluate the effectiveness of synthetic surfactant as compared to a biosurfactant (Surfactin). In this regard, vials with Surfactin showed better performance than vials with Tomadol 25-7 (synthetic surfactant).

The intensive, widespread, and ever-increasing applications of Cu-based pesticides in agriculture could potentially increase environmental exposures via different routes. Unlike ionic/bulk forms, the fate, transport, and toxicity of colloid-size Cu-based pesticides are not well studied. This paper provides evaluation outcomes of granule and dispersion characterizations, stability, and dissolution of colloid-size particles of Cu(OH)

Estimation of personal exposure to air pollution is needed to identify high-risk population and to develop mitigation strategies. In this study, an assessment of the potential effects of short-term exposure to PM10 and the elements bound within PM10 was conducted. Samples were obtained from the ten sub-cities of Addis Ababa (three sampling points from each) during the commuting time (traffic congestion and taxi queues). A particle counter consisting of a portable sampling unit with multi-fraction dust samplers was used for sample collection. The elemental composition was analyzed by inductively coupled plasma-optical emission spectroscopy (ICP-OES). The mean concentrations of PM10 ranged from 206 to 308 μg m−3. The highest concentrations of pollutants were found in the major open-market part of the city, Addis Ketema. The lowest concentrations were found at the old-town, Arada sub-cities. The concentration of trace elements (Fe, Cd, As, Cr, Pb, B, Ni, Co, Sn, Cu, and Zn) bound in PM10 ranged from below detectable limit to 0.981 μg m−3. Regardless of the sampling sub-city, the overall patterns of the mean concentration of elements bound in PM10 were found in the following increasing order of Cr < Cd < As < Co < Ni < Cu < Fe < Pb < Sn < B < Zn < Mn. The results showed that the primary source of Zn, Cr, and Cd may be emissions from on-road vehicles, tire and brake wear. Pb originates mainly from industries and suspended soil dust at the roadside, whereas As, Mn, and B are associated with dust resuspension and biomass and biofuel combustion, respectively. The carcinogenic and non-carcinogenic risks due to chronic exposure to trace elements bound in PM10 at the roadside were assessed in accordance with the U.S. Environmental Protection Agency (US EPA) guidelines. It was determined that Mn, As, and Cd contributed substantially to the inducement of non-carcinogenic health problems to children and adults as a result of exposure while in close proximity to the roadsides.

Population growth and unsustainable agricultural and industrial activities have led to a decrease in water quality and availability, causing ecological risks and challenging drinking water treatment plants to provide clean water. Many techniques are available for monitoring known water contaminants, but they are typically expensive and cumbersome requiring trained scientists or technicians to use them correctly. Biosensors provide the opportunity for simple to use, disposable or continuous tests, for monitoring many of the common contaminants and emerging contaminants that water-quality personnel are facing today. This chapter discusses the changing profile of water pollution and sources of regulated and emerging contaminants. A detailed discussion is provided on the monitoring of arsenic in groundwater and the current field-monitoring approaches. An introduction to biosensors is provided along with a discussion on arsenic biosensors that are developed for field applications. Finally, the future of biosensors for emerging contaminants is discussed.

Photocatalysis is an advanced process for treatment of air, wastewater, and drinking water, the primary advantage being its ability to mineralize many pollutants. Among several nanoscale arrangements of photocatalysts, there has been a strong push to develop them as thin films because of several advantages when compared to photocatalysts in suspension form. Within this context, the present review aims to provide a comprehensive overview of current knowledge regarding UV/vis and natural solar light photocatalysis of pollutants using titanium dioxide (TiO 2 ) nanoparticles in thin film form. Various synthesis techniques for the assembly of thin films, their characterization and comprehensive experimental results demonstrating their application as photocatalysts for decomposition of organic contaminants are summarized. Finally, current state of the art is discussed with associated challenges for the deployment of thin films for water treatment.

Acid-Red 18 is one of many azo dyes that are widely used in the textile industry. Wastewater effluent stream may contain untreated dyes that are toxic, carcinogenic, or mutagenic in character and are harmful to marine life. Degradation of Acid-Red 18 was investigated by a hybrid micro-electrolysis process that included iron (Fe) and Charcoal(C) under the influence of Ultrasonic waves (Fe/C/US). The highest removal efficiency by the system (98.86 %) was at pH 7, initial concentration of dye 25 mg/L, Fe/C concentration at 1: 1 ratio of 10 g/L over 60 min. The Acid Red 18 mineralization amount was found to be 76.5 % under optimal condition and through Total Organic Carbon (TOC) analysis by (Fe/C/US). Thus, Fe/C/US system, used as an electrochemical oxidation process, has advantages such as high performance, lower cost, and effective, simple operation in eliminating and degradation of organic pollutants such as acid-red 18 from aqueous solutions.

Estimation of personal exposure to air pollution is needed to identify high-risk population and to develop mitigation strategies. In this study, an assessment of the potential effects of short-term exposure to PM

Phosphorus is an essential and limited nutrient that is supplied by a depleting resource, mineral phosphate rock. Eutrophication is occurring in many water bodies which provides an opportunity to recover this nutrient from the water. One method of recovery is through adsorption; this study focused on fabricating a porous and granular adsorptive material for the removal and recovery of phosphate. Magnesium carbonate was combined with cellulose in varying weight ratios (0, 5, 10, 15, 20%) to synthesize pellets, which were then calcined to increase internal surface area. Physiochemical properties such as surface area, surface morphology, elemental composition, and crystal structure of the materials were characterized using Brunauer, Emmett, and Teller (BET) surface area analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The pellet proved to be uniform in composition and an increase in BET surface area correlated with an increase in cellulose content until pellet stability was lost. Phosphate adsorption using the pellets was studied via batch kinetics and sorption isotherms. The pseudo-second-order kinetics model fits best suggesting that the adsorption occurring was chemisorption. The isotherm model that fit best was the Langmuir isotherm, which showed that the maximum equilibrium adsorption capacity increased with an increase in cellulose content between 10% and 20%. The average adsorption capacity achieved in the triplicate isotherm study was 96.4 mg g(−1) for pellets synthesized with 15% cellulose. Overall, using cellulose and subsequent calcination created an additional internal surface area for adsorption of phosphate and suggested that granular materials can be modified for efficient removal and recovery of phosphate from water.

Use of biotrickling filter (BTF) for gas phase treatment of volatile trihalomethanes (THMs) stripped from water treatment plants could be an attractive treatment option. The aim of this study is to use laboratory-scale anaerobic BTF to treat gaseous chloroform (recalcitrant to biological transformation) as a model THM and compare results with aerobic BTF. Additional investigations were conducted to determine the microbial diversity present within the BTFs. Chloroform is a hydrophobic volatile THM known to be difficult to biodegrade. To improve the degradation process, ethanol was used as a cometabolite at a different ratio to chloroform. The experimental plan was designed to operate one BTF under anaerobic condition and the other one under aerobic acidic condition. Higher elimination capacity (EC) of 0.23 ± 0.01 g/[m(3)·h] was observed with a removal efficiency of 80.9% ± 4% for the aerobic BTF operating at pH 4 for the concentration ratio of 1:40 chloroform to ethanol. For similar ratio, the anaerobic BTF supported lower removal efficiency of 59% ± 10% with corresponding lower EC of 0.16 ± 0.01 g/[m(3)·h]. Carbon recovery acquired for anaerobic and aerobic BTFs was 59% and 63%, respectively. The loading rate for chloroform on both BTFs was 0.27 g/[m(3)·h] (per m(3) of filter bed volume). Variations of the microbial community were attributed to degradation of chloroform in each BTF. Azospira oryzae and Azospira restrica were the dominant bacteria and potential candidates for chloroform degradation for the anaerobic BTF, whereas Fusarium sp. and Fusarium solani were the dominant fungi and potential candidates for chloroform degradation in the aerobic BTF.