Chemosphere最新文献

This systematic review covers the urgent challenges posed by per- and polyfluoroalkyl substances (PFAS) in managing residuals from municipal, industrial, and waste treatment sources. It covers regulatory considerations, treatment technologies, residual management strategies, and critical conclusions and recommendations. A rigorous methodology was employed, utilizing scientific search engines and a wide array of peer-reviewed journal articles, technical reports, and regulatory guidance, to ensure the inclusion of the most relevant and up-to-date information on PFAS management of impacted residuals. The increasing public and regulatory focus underscores the persistence and environmental impact of PFAS. Emerging technologies for removing and sequestrating PFAS from environmental media are evaluated, and innovative destruction methods for addressing the residual media and the concentrated waste streams generated from such treatment processes are reviewed. Additionally, the evolving regulatory landscape in the United States is summarized and insights into the complexities of PFAS in residual management are discussed. Overall, this systematic review serves as a vital resource to inform stakeholders, guide research, and facilitate responsible PFAS management, emphasizing the pressing need for effective residual management solutions amidst evolving regulations and persistent environmental threats.

In the current electrolytic manganese industry, iron separation and reuse from iron-rich manganese ore leachate (IRMOL) has become one of the most pressing challenges. This study aimed to investigate the optimal conditions for iron separation from IRMOL and to assess the economic and practical advantages of iron separation or removal in industrial manufacturing. To identify more cost-effective and technologically advanced production circumstances, we examined five key elements that weaken Fe(OH)₃ colloidal production conditions in enterprises: reaction temperature, pH, crystal species, aging and reaction time. The screening results showed that when the conditions were optimized, the efficiency of reducing manganese loss decreased from 6.15% to 4.69%. Additionally, the generation of iron-rich electrolytic manganese residue (IREMR) was decreased by 44.32%, and the filtration velocity of IREMR increased from 0.0030 to 0.0220 mL/(s·cm²) compared to the production conditions before optimization at the enterprises. Through multiphase equilibria modeling with Visual MINTEQ, we have determined that raising the temperature and pH levels increases the expenses associated with chemicals and energy usage and results in an elevation of Fe(OH)₂⁺ concentration. This can lead to the creation of Fe(OH)₃ colloidal, causing a high water content in IREMR, inefficient filtration, and significant loss of manganese. This strategy is highly significant for the production of electrolytic manganese and the reduction of electrolytic manganese residue.

Fossil fuel combustion generates nitrogen oxides (NO + NO₂ = NO_x), which pose threats to the environment and human health. Although commercial products containing titanium dioxide (TiO₂) can remedy NO_x pollution by photocatalysis, they only function in the ultraviolet (UV). On the other hand, bismuth oxybromide (BiOBr) is active in the visible. BiOBr is stable, affordable, and non-toxic, making it an appealing alternative. In addition, nanoparticulate Bi metal can further enhance visible light absorption through its surface plasmon properties and charge carrier lifetime by spatially separating charge. In this study, to enhance the visible-light activity of TiO₂-based photocatalysts for NO_x pollution, a composite of Bi-decorated BiOBr/TiO₂ was synthesised using a solvothermal method across varying the Ti/Bi atomic ratio (0.2, 2.2, 4.4, and 6.6), and synthesis duration (6h, 12h, and 18h). The photocatalytic performance of the synthesised composites for NO gas removal was investigated using an adapted ISO method (22197-1:2016). Analysis showed that the preferential growth of the (010) crystal facet in BiOBr and the presence of Bi metal both play an important role in the superior photocatalytic activity seen in our Bi-decorated BiOBr/TiO₂ composite. The composites were characterised using X-ray diffraction (XRD), attenuated total reflectance - Fourier transform infrared spectroscopy (ATR-FTIR), high-resolution scanning electron microscopy (HR-SEM), UV-Vis diffuse reflectance (DRS) spectroscopy, transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, Brunauer-Emmett-Teller (BET) analysis, thermogravimetric analysis (TGA), and diffuse reflectance transient absorption spectroscopy (DR-TAS). Our research shows that the Bi/BiOBr-TiO₂ composite synthesised through a 12h solvothermal method with a Ti/Bi atomic ratio of 4.4 exhibits the highest photocatalytic performance towards both NO and NO₂ oxidation; with 32.8% and 54.9% NO removal and 15.1% and 29.5% NO₂ under visible and UV lamps, respectively.

Cylindrospermopsin (CYN), a cyanotoxin with worldwide distribution, is gaining increased attention due to its bioaccumulation potential and toxicological effects. Previous research suggests that CYN may interact with other environmental contaminants, potentially amplifying its toxicity. To address this concern, the present study investigated the combined effects of CYN with arsenic (As) and cadmium (Cd) on human immune cell lines, Jurkat and THP-1. Cytotoxicity tests showed that As and Cd significantly decreased the viability of both cell lines after 24 and 48 h of exposure. The EC₅₀ (24 h) values for Jurkat cells were 13.15 ± 1.97 (As) and 36.92 ± 3.77 μM (Cd), respectively, while for THP-1, the EC₅₀ (24 h) values were 46.48 ± 0.17 for As and 55.09 ± 4.98 μM for Cd. Furthermore, individual contaminants and their mixtures with CYN impaired monocyte differentiation into macrophages. The effect on mRNA expression of some cytokines (TNF-α, INF-γ, IL-2, IL-6 and IL-8) was also assessed. In the Jurkat cell line, As upregulated IL-8 expression while Cd increased the expression of all interleukins. Exposure to binary combinations (CYN + As, and CYN + Cd) increased IL-2 and INF-γ expression. In THP-1 cells, As elevated IL-8 and INF-γ expression, whereas Cd caused an increase in TNF-α and INF-γ expression. Exposure to CYN + As up-regulated IL-8 and INF-γ expression, while the CYN + Cd combination down-regulated TNF-α expression. These findings highlight the complex interactions between contaminants, emphasizing the need for evaluating combined effects in risk assessments.

The quest for a good life, urbanization, and industrialization have led to the widespread distribution of endocrine-disrupting chemicals (EDCs) in water bodies through anthropogenic activities. This poses an imminent threat to both human and environmental health. In recent years, the utilization of advance materials for the removal of EDCs from wastewater has attracted a lot of attention. Metal-oxide nanocatalysts have emerged as promising candidates due to their high surface area, reactivity, and tunable properties, as well as enhanced surface properties such as mesoporous structures and hierarchical morphologies that allow for increased adsorption capacity, improved photocatalytic activity, and enhanced selectivity towards specific EDCs. As a result, they have shown extraordinary efficacy in removing a wide range of EDCs from aqueous solutions, including pharmaceuticals, agrochemicals, personal care items, and industrial chemicals. This study give insight into the unique physicochemical characteristics of metal-oxide nanocatalysts to effectively and efficiently remove harmful EDCs from wastewater. It also discussed the advances in the synthesis, and properties of metal-oxide nanocatalysts, and insight into understanding the fundamental mechanisms underlying the adsorption and degradation of EDCs on metal-oxide nanocatalysts using advanced characterization techniques such as spectroscopic analysis and electron microscopy. The findings of the study present metal-oxide nanocatalysts as a good candidate for the spontaneous sequestration of EDCs from wastewater is an intriguing approach to mitigating water pollution and safeguarding public health and the environment.

As brominated flame retardants are phased out and regulations on their use become stricter, concerns over organophosphate flame retardants (OPFRs) have increased due to their high production. In response, this study aimed to screen the potential toxicity of emerging OPFRs using in vitro Tox21 assays and in silico molecular docking analysis. For 48 OPFRs collected from the literature, we investigated their bioactivity with human nuclear receptors using Tox21 data, focusing on pathways related to endocrine disruption (ERs, AR), stress response (GR), energy homeostasis (PPARs, FXR), and detoxification (PXR, CAR). For OPFRs not tested in Tox21 assays, molecular docking simulations were performed to predict binding potential. Results showed that CAR/PXR and FXR had relatively high reactivity with diverse OPFRs, indicating potential molecular initiating events (MIEs). Among the 48 OPFRs, 28 interacted with one or more receptors, suggesting they may act as potential stressors of adverse outcome pathways (AOPs) leading to various human diseases. Aryl- and halogenated-OPFRs displayed higher bioactivity compared to alkyl-OPFRs. Additionally, as the logKow value and carbon number of OPFRs increased, their interaction with nuclear receptors also increased. These structure- and physicochemistry-dependent bioactivities provide insights for designing safer OPFRs to avoid regrettable substitutions. Of these prioritized OPFRs, 13 showed low oral points-of-departure (POD) values under 100 mg/kg/day. In contrast, the other 15 OPFRs lacked sufficient data or exhibited less severe toxicity, despite being predicted to be of high concern in our analysis. Since several OPFRs are commonly used in consumer products that can lead to daily human exposure, we suggest that these OPFRs have the potential to reveal undisclosed effects and should therefore undergo further assessment.

Citizens grow their own fruits and vegetables in allotment gardens in the vicinity of a fluorochemical production plant (FCPP) in The Netherlands. Historic emissions and the subsequent atmospheric deposition of perfluorooctanoic acid (PFOA) and GenX (hexafluoropropylene oxide-dimer acid/HFPO-DA) from the FCPP have resulted in the nearby environment being contaminated with per- and polyfluoroalkyl substances (PFASs). This research aimed to investigate the levels of PFASs in garden produce and whether a gradient can be observed in relation to distance from the FCPP. Furthermore, differences between certain types of fruits and vegetables were explored, as well as a potential relation between the measured concentrations in garden produce and soil. 737 fruit and vegetable samples were collected from 17 allotments and 4 gardens up to 20 km from the FCPP, along with soil and water samples. Garden produce included fruits, potatoes, fruiting vegetables, brassicas, leafy vegetables, root vegetables, bulb vegetables, legumes and stem vegetables. PFASs concentrations in the samples were quantified using a very sensitive UPLC-MS/MS method. PFASs were detected in most samples above the analytical limit of detection (0.3-12.5 pg/g ww). PFOA and GenX were found in the highest concentrations (up to 5280 pg/g ww GenX and 3020 pg/g ww PFOA) in garden produce sampled downwind and close to the FCPP. Other PFASs were also found, but at (much) lower levels. Field-derived bioaccumulation factors (BAFs) were calculated for PFOA and GenX. The BAFs for PFOA were shown to be approximately 1 order of magnitude lower than BAFs from other studies. This may be explained by aging of the PFASs contamination and the intense cultivation of the garden plots. This study shows that PFOA and GenX can end up in garden produce and this will result in human exposure when the garden produce is consumed.

Urban areas face increasing pressures on water resources, necessitating innovative approaches to climate adaptation and water quality management. Nature-based Solutions (NbS) offer a sustainable pathway, yet their integration with existing infrastructure in urban settings remains occasional. This study presents a novel hybrid system-Sequential Sedimentation Biofiltration System (SSBS)-designed for stormwater treatment within confined urban spaces. The system was adjusted to the existing stormwater infrastructure by integrating a sedimentation tank (SED), three Permeable Reactive Barriers (PRBs), and a biofiltration zone (BIO). The SSBS was evaluated for its efficiency in removing nutrients and sediments, focusing on the performance of PRBs. Our findings showed limited sediment removal in SED and PRBs due to spatial constraints and a high Hydraulic Loading Rate (HLR = 1.31 m/d), achieving an average of 13.6% Total Suspended Solids (TSS) removal. However, PRBs demonstrated effective removal of ammonium (43.4%) and phosphate (59.3%), potentially due to sorption and biofilm activity, with dominant microbial communities including Proteobacteria, Bacteroidetes, and nutrient-transforming taxa such as Nitrospirae. Interestingly, PRBs increased nitrite levels (57.1%) but did not significantly impact nitrate, chloride, or TSS. The BIO zone further enhanced nutrient retention (56% PO₄-P) and served as a sink for TSS (52%). This study underscores the potential for integrating traditional urban infrastructure with NbS in a sequential stormwater treatment system, demonstrating its effectiveness in space-constrained urban environments.

The production of increasing amounts of high salinity wastewaters in our industrialized society has prioritized their treatment to prevent environmental pollution. The partial nitritation - anammox (PN/A) process for nitrogen removal has been little investigated for hypersaline wastewaters (salinity greater than 3%). In the investigation presented here, single-stage versus two-stage partial nitritation - anammox (PN/A) reactor systems for deammonification at 4% (40 g/kg) saline conditions were investigated and compared in completely mixed fixed bed reactors. In the two-stage system, the first stage reactor achieved a nitritation rate of 1.9 gN/L-reactor/d. Effluent from the partial nitritation reactor was then fed to the second two-stage anammox reactor and the maximal nitrogen removal of 0.8 g/L-reactor/d was achieved. The dominant microbial species for the ammonia oxidizing and anammox reactions in the nitritation (first) reactor and the second reactor were identified as Nitrosococcus oceani and Candidatus Scalindua wagneri, respectively, both obligate halophiles. In the single-stage reactor, deammonification rates reached 0.6 gN/L-reactor/d. Nitrosomonas marina and Candidatus Scalindua wagneri were the dominant AOB and anammox bacteria, respectively. Maintaining free ammonia (FA) concentrations above 1 mg/L was found to selectively inhibit nitrite oxidizing bacteria (NOB) and resulted in long term stable nitritation. At FA concentrations lower than 1 mg/L, nitrate began to appear after 20 days of reactor operation. Nitritation was recovered after increasing FA in the reactor to inhibitory concentrations. Overall N₂O emissions were shown to be significantly lower in the single-stage PN/A reactor than the two stage PN/A reactor system.

It has been proposed for the first time to investigate the possibility to implement micro-inter-electrode distances in electrocoagulation (EC) in order to improve both the treatment and energy efficiencies compared to conventional EC cells with centimetric distances. The study has been performed in a microfluidic monopolar flow-by filter-press cell for the treatment of simulated and real low-conductivity (0.5-1 mS cm^-1) laundry wastewaters. The influences of interelectrode distance (d_elec) (100-10,000 μm), applied current density (j_app) (10-200 mA cm^-2), and types of anode materials (iron, aluminium and stainless steel) have been studied. The removal of representative organic pollutant (i.e., paracetamol at 15 mg L^-1) as well as of total organic carbon (TOC) content (312 mg-C L^-1) from actual wastewater was noticed, including at micro-distances. Optimal treatment capacities were obtained with d_elec of 0.5 mm (57% TOC removed), 3 mm (58% TOC removed) and 10 mm (41% TOC removed) and with j_app of 70 mA cm^-2, 40 mA cm^-2 and 20 mA cm^-2 respectively, using stainless steel anode. It led to reduced energy requirement at micro-distances (16 kWh g-TOC^-1 at 500 μm) compared to millimetric gap (19 kWh g-TOC^-1 at 3 mm, 40 kWh g-TOC^-1 at 10 mm). Contrastingly, more sludge was generated with micrometric distance (172 g-sludge g-TOC^-1 at 500 μm) compared to larger gaps (95 g-sludge g-TOC^-1 at 3 mm, 87 g-sludge g-TOC^-1 at 10 mm) due to higher optimal j_app at low distances. The efficiency was maximal with an aluminium electrode, but this anode remained inapplicable with micro-distances using the current reactor design, given the high sludge production between the cathode and anode.