Environmental science. Advances最新文献

The “forever chemicals”, per- and polyfluoroalkyl substances (PFAS), have become a threat to public health and environment because of their toxicity and bioaccumulation. Addressing this critical issue, we develop a state-of-the-art nanocomposite adsorbent by covalently grafting amine functional groups onto graphene oxide (GO) surfaces and making them magnetic with iron-oxide (Fe₃O₄) nanoparticles. This process results in the creation of magnetic amine-functionalized graphene oxide (MAGO). The efficiency of MAGO is evaluated in the adsorptive removal of perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), and perfluorobutane sulfonate (PFBS) as model long-chain and short-chain PFAS under different experimental conditions. Our findings reveal that MAGO achieves remarkable removal rates—exceeding 95% for long-chain PFAS and 85% for short-chain PFAS within just 30 minutes—demonstrating not only rapid kinetics but also a resilience across pH levels from 4 to 7. These results are indicative of the synergistic effects of GO and amine groups, harnessing both electrostatic and hydrophobic interactions to adsorb PFAS molecules. MAGO not only shows potent pollutant removal but also has impressive regeneration capabilities. Moreover, we demonstrate a novel liquid phase extraction method for PFAS detection, utilizing a colored methylene blue-PFAS complex for spectrophotometric analysis.

Per- and polyfluoroalkyl substances (PFAS) are a group of synthetic, highly fluorinated aliphatic compounds, commonly utilised in a wide variety of consumer products with diverse applications. Since the genesis of these compounds, a growing body of evidence has demonstrated adverse health effects associated with PFAS exposure. In a racially diverse cohort of 459 pregnant mothers, demographically weighted towards minority representation (black 44.4%, white 38.4%, other 17.2%), across three major populous cities of the US, PFAS profiling was performed. Nine distinct PFAS species were quantified using mass spectrometry in plasma samples collected during the third trimester. Multivariable logistic and linear regression analyses were conducted to interrogate the associations of PFAS with gestational and birth outcomes: gestational diabetes, preeclampsia, gestational age at delivery, low birth weight, birth weight-, birth length- and head circumference-for-gestational-age. Detectable levels for eight out of nine profiled PFAS species were found in the plasma of pregnant mothers with a median range of 0.1–2.70 ng ml⁻¹. Using a mixtures approach, we observe that increased quantile-based g-computation (Qg-comp) “total” PFAS levels were associated with increased newborn birth-weight-for-gestational-age (β 1.28; 95% CI 1.07–1.52; FDR p 0.006). In study centre-stratified analyses, we observed a similar trend in Boston pregnant mothers, with Qg-comp total PFAS associated with higher newborn birth-weight-for-gestational-age (β 1.39; 95% CI 1.01–1.92, FDR p 0.05). We additionally found elevated PFUA concentrations were associated with longer gestational terms in San Diego pregnant mothers (β 0.60; 95% CI 0.18–1.02, FDR p 0.05). In this multi-city study, we detected lower levels of PFAS than in many previous US environmental studies, concordant with current US trends indicating environmental PFAS levels are falling, and we note geographical variation in the associations between PFAS levels and birth outcomes.

Fluorotelomer (FT) alcohols (FTOHs) belong to the subclass of per- and polyfluoroalkyl substances (PFAS) and are used as building blocks of FT-based side chain fluorinated polymers (SCFPs), which are applied to consumer products to provide hydro- and oleophobic characteristics. FTOHs are consistently detected in consumer products, indicating FTOHs as major degradation products of FT-based SCFPs. Literature on FTOHs indicates that much is known about the release of FTOHs during the production, throughout the lifetime, and at the end-of-life of consumer products. This Perspective combines information from FTOHs in consumer products with sufficient knowledge on FTOH volatility, partitioning to the gas phase, and transformation to perfluorocarboxylates (PFCAs) to understand the extent of FTOH release to the environment. In the indoor environment, FTOHs are released in textile factories to the air during the production of consumer products, indicating a potential inhalation risk for the workers. Meanwhile, indoor air FTOH levels at residential sites are estimated to pose low inhalation risk to humans based on studies of 8:2 FTOH, which is known to undergo human metabolism to perfluorooctanoate (PFOA). Release of FTOHs from FT-based SCFP-applied consumer products to the indoor environment throughout the lifetime of the products is known, as well as release to the outdoor environment through washing, weathering, or drying. At the end-of-life of consumer products, FTOHs are released to air from landfills and can be detected in biosolids. Future policies need to not only account for FTOH presence in consumer products, but also the known FTOH volatility, partitioning to the gas phase, and transformation to PFCAs.

The North East coast of England experienced a mass mortality event in late 2021 affecting millions of crabs and lobsters. The die-off coincided with the redevelopment of one of the UK's flagship ports, prompting local scientists to suggest the remobilization of dredged industrial contaminants as a cause. A multi-agency investigation found no definitive causal factor; however, re-evaluation of data by consultants drew a different conclusion, linking the industrial compound pyridine to the crustacean deaths. Authors of an unpublished study subsequently claimed that their data demonstrated pyridine to be exceptionally toxic and that their modeling explained the coastal distribution of washups. These data were presented to a cross-party Environmental, Fisheries and Rural Affairs (EFRA) committee in the UK parliament and led to the commissioning of an independent panel to review the data. This panel was also unable to identify a definitive cause, but found that a major role for pyridine was ‘very unlikely’. Unfortunately, the debate has been highly politicised, with misleading information aired by the two leading political parties. Here, several members of that independent review panel refute the pyridine link to the mass mortality, based on both reported data and the known chemistry and behaviour of this molecule, and highlight where the science has been misrepresented by the media.

The European Union and governments of various economies in the world are currently developing supply chain legislation for businesses, aiming to protect the environment and human rights in supply chains. These laws regulate firms active on home markets in these countries, but in terms of environmental and human rights risks also apply to global supply chains. Legislative initiatives assume that firms have the ability to influence many suppliers and their conditions of production abroad. Illustrated by the urgent case of garment production exported to Europe, we conclude that current import–export relations could limit the scope and impact of such supply chain legislation. If patterns as visible in the garment sector hold more broadly, policymakers that are ambitious about the impact of supply chain legislation on environment and human rights face a policy trilemma: they must sacrifice one out of three current design features of such legislation: designing legislation unilaterally for their home markets, letting regulation apply to supply chains across the world, or giving firms the ability to freely choose their suppliers. We discuss the different combinations of design options that could advance sustainability in supply chains.

Modified yttria- and scandia-doped zirconium oxides were exploited for the development of an effective electrochemical sensor for the simultaneous detection of dihydroxy benzene (DHB) isomers, i.e. hydroquinone (HQ), catechol (CC) and resorcinol (RS). A morphological, microstructural and electrochemical characterization, by scanning electron microscopy (SEM), infrared spectroscopy (FT-IR), X-ray diffraction (XRD), electrical impedance spectroscopy (EIS), cyclic voltammetry (CV), and square wave voltammetry (SWV), of pure zirconium oxide, zirconium oxide doped with 8% yttria and zirconium oxide doped with 10% scandium (ZrO₂, ZrO₂8Y, and ZrO₂10Sc, respectively), were carried out. Modified electrochemical sensors were fabricated by using a screen-printed carbon electrode (SPCE). Electrochemical analysis conducted in phosphate buffer solution (0.01 M PBS; pH = 7.4) showed the great ability of the ZrO₂10Sc/SPCE sensor to detect simultaneously DHB isomers with high sensitivity. SWV analysis performed with this sensor showed the lowest limits of detection (LODs) among all sensors tested, with values of 0.92, 0.69, and 5.61 nM, for hydroquinone (HQ), catechol (CC), and resorcinol (RS), respectively. In addition, the sensor shows good repeatability and simultaneous detection capability for all DHB isomers. This sensor also showed excellent results for the detection of HQ, CC, and RS in tap and mineral water samples, with good recoveries (90–116%).

Dissolved oxygen (DO) is an important variable for rivers, which controls many biogeochemical processes within rivers and the survival of aquatic species. Therefore, accurate forecasting of DO is of great importance. This study proposes two models, including AR-RBF by leveraging the additive regression (AR) of radial basis function (RBF) neural networks and MLP-RF by stacking multilayer perceptron (MLP) and random forest (RF), for the prediction of daily DO with multiple forecast horizons (1 day ahead to 15 days ahead) in the Mississippi River using a long-term observed dataset from the Baton Rouge station. Two input scenarios were considered: scenario A includes mean water temperature and a certain number of preceding DO values and scenario B comprises solely the aforementioned number of preceding DO values while entirely disregarding exogenous variables. The AR-RBF and stacked MLP-RF models excel in short-term forecasting and offer sufficiently accurate predictions for medium-term horizons of up to 15 days. For instance, in 3 day ahead predictions, the root mean square error (RMSE) amounts to 0.28 mg L⁻¹, with the mean absolute percentage error (MAPE) hovering around 2.5% in the worst-case scenario. Similarly, for 15 day ahead forecasts, RMSE remains below 0.93 mg L⁻¹, with MAPE not exceeding 8.2%, even under the worst-case scenario. Both models effectively capture the extreme values and the fluctuations of DO. However, as the forecasting horizon is extended, both models experience a decrease in accuracy, which is particularly evident for scenario B when the average water temperature is not included in the input variables. When examining longer forecasting horizons in the study, AR-RBF demonstrates a more restrained bias as compared to the stacked MLP-RF model. The consistently robust performance of the models, in comparison to prior research on DO levels in US rivers, underscores their potential as more effective tools for predicting such an essential water quality parameter.

The world's increasing dependency on fossil fuels has become a significant energy and environmental concern as they contribute 83% of the global energy supply and produce large amounts of carbon dioxide. Biohythane, a blend of biomethane (5–10%) and biohydrogen (50–60%), is emerging as a promising and environmentally friendly alternative fuel derived from organic wastes and offers a sustainable solution. The existing methods of biohythane production suffer from major limitations of being cost- and labor-intensive due to adopting bulk substrate pretreatment to enhance biohythane yield thereby limiting their industrial applications. In this study, we have developed a synthetic microbial consortium (E(C2)Tx) for anaerobic digestion by combining various organic wastes and subjecting them to heat pre-treatment and acclimatization to enrich biohydrogen producers and methanogens, respectively. Raw cow dung was anaerobically digested as the substrate with E(C2)Tx and this resulted in the production of biohythane with 3% biohydrogen and 36% biomethane. The consortia designing strategy avoided any bulk substrate pretreatment and only included the pretreatment of the inoculum which is used in four times less volume than the substrate. A 16S rRNA gene based metagenomic analysis revealed that the CD samples treated with E(C2)Tx were enriched in cellulolytic and hydrogen-producing Firmicutes, along with methylotrophic and hydrogenotrophic methanogens. The developed technology offers promising commercial benefits by requiring less energy for biohythane production. In addition, it offers environmental advantages by providing an efficient CD waste management alternative and reducing climatic impact by lowering greenhouse gas emissions associated with fossil fuel burning. Using a waste complementarity approach for consortia designing aligns with the principles of circular economy and presents a sustainable, scalable energy solution. The developed method can support the growing energy market by increasing biohythane yield and lowering its production cost.

The injected tracer technique using nanoparticles has evoked a lot of research interest in hydrogeological research as it encompasses a broad spectrum of applications in water resource management. The present work deals with developing carbon dot embedded silica-based nanocomposites using a microwave-assisted co-polycondensation method. The synthesized carbon dot-embedded silica nanocomposites have been characterized for their structural and functional characteristics using UV-visible spectroscopy, photoluminescence spectroscopy (PL), lifetime analysis, Raman spectroscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared spectroscopy (FTIR) and X-ray Diffractometry (XRD). The results obtained showed that carbon dots having a size of less than 5 nm had been successfully embedded into the silica structure, and the nanocomposite as such shows interesting optical properties. Laboratory scale column experimental studies were further conducted to ascertain the applications of the synthesized carbon dot-embedded silica nanocomposite for hydrological studies. Experiments were performed by varying the filling materials (sand/soil) in the column during which different concentrations of the nanotracer were injected under the continuous flow of water at a constant flow rate of 5 ml min⁻¹ followed by monitoring the detection of carbon dots for a definite time. The developed nanocomposite was found to exhibit satisfactory results in terms of the detection and recovery of carbon dots when injected as a tracer in an experimental hydrological study. About 99% of the nano tracer could be regained when ∼0.5 g of the CD-SiO₂ nanotracer is injected into the column and the detection was much faster with a peak detection time of 6 minutes. The better traceability and retention of the original optical properties of the developed tracer under different experimental conditions could be attributed to the optimal size of the nanocomposite system. Thus, the current challenges faced in groundwater flow analysis such as huge time consumption/expenses can be resolved to a significant extent considering the better traceability of the developed nanotracer.

Ammonia recovery from food waste (including its liquid digestate) is highly emphasized in wastewater treatment and management. Among various membrane-based separation technologies, bipolar membrane electrodialysis (BMED) without anion exchange membranes (AEMs) is an attractive candidate for selective ammonia separation with reduced scaling problems. In this study, a bench-scale BMED stack was built using 5 pairs of cation exchange membranes (CEMs) and bipolar membranes (BPMs). A simulated food liquid digestate was treated using a lab-scale BMED stack to examine the ammonia separation with 3 different intermembrane distances (0.82, 1.64, and 2.46 mm). The highest electric current and ammonia separation were obtained for the intermembrane distance of 1.64 mm, while the BMED stack with 3 spacer gaskets (2.46 mm) still showed comparable separation performance without significant decreases in electric current or ammonia recovery. The residual Ca²⁺ and Mg²⁺ in the cleaning-in-place (CIP) solutions indicated that there were no noticeable scaling problems during the BMED operation. Finally, the pH polarization between the base and feed cells was found to minimize the ammonia back-diffusion even with the highly accumulated ammonia concentration (>11 000 mg_N L⁻¹) in the base cell. With the relatively low energy requirement (1.24–6.78 kW h kg_N⁻¹), BMED lacking AEMs with wide intermembrane distances was confirmed to be a sustainable candidate for ammonia recovery from wastewater with high levels of ammonia.