Environmental Science: Processes & Impacts最新文献

Replacement of internal combustion engine vehicles with battery electric vehicles (EVs) is expected to impact air quality. Previous projections, often relying on emissions inventories of precursors with high uncertainties, have yielded results that vary by model parameters and assumptions. There remains little empirical investigation of the real-world effects, particularly for the low yet growing levels of electrification in the United States. Here county-level vehicle registrations and measurements from ground-level air monitors from 2018 through 2023 were used to investigate the impacts of EV penetration on annual and seasonal concentrations of criteria air pollutants in the United States. Fixed effects regression analysis revealed that rising EV penetration was associated with reductions in mean annual concentrations of nitrogen oxides (NO_x as the sum of NO₂ and NO), carbon monoxide (CO), and fine particulate matter (PM_2.5) and in mean summer season concentrations of ozone (O₃). By contrast, there was a potential increase in sulfur dioxide (SO₂). The findings demonstrate empirical improvements in air quality associated with EV adoption yet highlight the risk of a continued reliance on fossil fuels. Strategic policies that support enhanced EV adoption must support commensurate expansion of renewable energy access in order to maximize the air quality benefits of the technology.

Mercury (Hg) is a highly toxic heavy metal pollutant characterized by bioaccumulation potential and long-range transport capacity. As one of its critical environmental sinks, soil Hg contamination has attracted significant scientific and regulatory attention. Particulate organic carbon (POC) plays a pivotal role in governing the speciation and stabilization of Hg in soils due to its rapid turnover rate and strong metal-binding capacity, yet current understanding of these mechanisms remains notably inadequate. This study systematically investigated the variability in SOC fraction enrichment across different soil types and elucidated the POC-mediated Hg stabilization mechanisms in soil through comprehensive characterization analyses. The experimental results demonstrate that POC can adsorb more Hg²⁺, thereby promoting Hg reduction in the soil environment. At the same time, the content of available Hg in POC is lower than that of mineral-associated organic carbon (MAOC), and the residual Hg is higher than that of MAOC. Therefore, it can be considered that POC has a certain promoting effect on the stability of Hg in soil. Furthermore, SEM-EDS results showed that the Hg concentration in POC was higher than that in MAOC. Fourier transform infrared spectroscopy (FTIR) showed that –OH, –COOH and –SH were involved in the adsorption of Hg. These findings establish that POC content directly regulates both the concentration and chemical forms of Hg in farmland soil, suggesting that POC management could serve as a nature-based strategy for mitigating Hg availability and mobility in Hg-contaminated agricultural soil.

Understanding the complex interplay between hydrodynamic conditions and the dynamics of antibiotic adsorption by microplastics (MPs) is essential for accurately assessing environmental risks in aquatic systems. This study systematically investigated the adsorption mechanisms of ofloxacin (OFL) onto polystyrene (PS) and polyvinyl chloride (PVC) MPs under varying hydrodynamic conditions. Batch adsorption experiments demonstrated that the adsorption of both materials for OFL follows pseudo-second-order kinetic profiles (R² > 0.99) and exhibits Freundlich isothermal behavior (R² > 0.98), suggesting that heterogeneous surface-driven multilayer adsorption is the predominant mechanism. Material characterization revealed that the physicochemical properties of PS featured a significantly higher specific surface area (2.10 m² g⁻¹) than PVC (0.87 m² g⁻¹), yet their equilibrium adsorption capacities were comparable (29.33 µg g⁻¹ for PS vs. 30.47 µg g⁻¹ for PVC under high agitation). This discrepancy implies that factors such as surface roughness and micropore architecture, rather than merely specific surface area, play a dominant role in determining adsorption efficiency. Fourier-transform infrared (FTIR) spectroscopy confirmed the absence of new covalent bonds, indicating that physical interactions—such as hydrophobic interactions, van der Waals forces, and micropore filling—are the primary adsorption mechanisms. Hydrodynamic conditions emerged as a critical regulator of adsorption dynamics. Increasing turbulence intensity (40–200 rpm) shortened the equilibrium attainment time by more than 83% and enhanced equilibrium adsorption capacities (with a maximum increase of 16.2% for PS and 6.5% for PVC). These findings highlight that hydrodynamic forcing caused by natural flow regimes and anthropogenic disturbances can exacerbate microplastic–antibiotic composite contamination through enhanced adsorption processes.

Non-exhaust emissions (e.g., automotive brake and tire wear) are quickly replacing exhaust emissions as the dominant traffic particulate pollutant. A significant fraction of the emissions are complex mixtures of organic compounds whose composition is not well known. Due to their unique health implications, knowledge of the composition of ultrafine particles (<100 nm in diameter) is of particular interest. Here we report on the size-selected organic composition of ultrafine particles nucleated during high brake temperature conditions generated using a custom brake dynamometer system and two common brake pad types. Using high resolution mass spectrometry, we find that the organic composition of these particles is dominated by species containing oxygen (CHO) and nitrogen (CHN/CHON). Many of these compounds are unsaturated and are attributed to the thermal degradation of resin material used in the pad formulation. Other abundant compounds include various glycols and amines, several of which are unequivocally identified and discussed as potential marker compounds for brake wear emissions. A significant fraction of highly oxidized, low volatility species observed in ultrafine particles could not be conclusively attributed to the thermal degradation of the brake material, indicating the presence of chemical pathways unique to the frictional heating process. This emphasizes the importance of using a brake dynamometer to generate brake wear particles as opposed to other strategies.

The fractionation of extracellular polymeric substances (EPSs) on mineral surfaces alters their composition and reactivity, thereby influencing heavy metal behavior in the environment. However, the molecular-level mechanisms governing how this process affects metal-binding properties remain unclear. Hence, this study combined multispectral techniques and chemometrics to investigate the adsorptive fractionation of EPSs on minerals and its impact on heavy metal binding. Excitation–emission matrix coupled with parallel factor analysis (EEM-PARAFAC) demonstrated that aromatic and protein-like components were preferentially adsorbed on hematite (Hema) and goethite (Goet). Two-dimensional correlation spectroscopy (2D-COS) further indicated that protein-like substances were adsorbed prior to fulvic-like substances, following the sequence: tyrosine-like > tryptophan-like > fulvic-like substances. Notably, the fractionation process altered the binding affinity and order of Cu²⁺ to EPS components. Adsorption onto Hema reduced the copper-binding affinity of EPSs, whereas adsorption onto Goet enhanced it. This difference may be attributed to changes in carboxyl and polysaccharide groups within the EPS. This study elucidates the influence of EPS fractionation on mineral surfaces regarding heavy metal binding at the molecular level. These findings enhance our understanding of the biogeochemical behavior of heavy metals in the presence of mineral–organic composites across aquatic and terrestrial ecosystems, providing a theoretical foundation for environmental remediation.

Polycyclic aromatic hydrocarbons (PAHs) are detrimental to human health and the environment as a hazardous persistent organic pollutant of environmental concern. Research is emerging on the occurrence, form, migration characteristics and removal of PAHs from runoff stormwater by bioretention cells. This review analyses the sources of PAHs, the characteristics of their concentration distribution and their migration pattern in stormwater runoff. The mechanism of PAH removal by bioretention cells, the purification effects of different fillers and their influencing factors, and the accumulation characteristics of PAHs in bioretention cells are analysed, and the influence mechanism of PAH accumulation on the performance of bioretention cells is summarised. It is noteworthy that the typical concentration range of polycyclic aromatic hydrocarbons (PAHs) in urban stormwater runoff is 0.65–13.4 µg L⁻¹. The average PAH concentrations in surface runoff vary across different functional zones, with levels in industrial and commercial areas generally being significantly higher than those in residential areas, green spaces, and other functional zones. Studies have shown that the overall removal efficiency of PAHs by bioretention cells can consistently exceed 80%, demonstrating their significant potential for pollution control. Based on existing research progress, this review further proposes that future efforts should focus on the following research directions: (1) induction of the decomposition of PAHs accumulated in bioretention cells into degradable products; (2) search for more effective fillers to improve their removal efficiency; (3) effects of PAH contamination on microbial functions in the filler of bioretention cells; and (4) synergistic effects of PAHs with other pollutants on bioretention cells. This review evaluates the actual PAH removal performance of bioretention facilities, which holds significant scientific and practical value for optimizing the design of low-impact development facilities and ensuring the safety of the urban water environment.

Poultry by-products (PBPs) are increasingly used in aquacultural environments and have emerged as a potential source of veterinary antibiotics and pathogens; however, the ecological risks remain unclear. This study investigated tissue-specific accumulation of 34 antibiotics and microbial risks in yellow catfish (Pelteobagrus fulvidraco) following exposure to PBPs. Among the 11 tissues analyzed, the data suggest that over 93% of antibiotic residues may be derived from PBPs, with concentrations ranging from 1.21 to 354.31 ng g⁻¹, with the highest concentrations observed in bile, kidney, and liver. Bioaccumulation of tilmicosin, enrofloxacin, and florfenicol occurred via both dietary intake and dermal exposure, with log bioaccumulation factor (BAF) values of up to 3.79 for bile. High-throughput 16S rRNA sequencing revealed the consistent occurrence of Acinetobacter and Mycobacterium across fish tissues, feed, and water, with 40% of dominant taxa identified as known or suspected cross-species potentially pathogenic genera. A significant reduction in skin microbiota diversity further indicates a possible risk of exposure-induced dysbiosis. These findings highlight PBPs as vectors of both antibiotic residues and microbial disturbance, underscoring the need for targeted control of PBP-derived risks to safeguard freshwater ecosystem health.

Plastics, particularly polyethylene terephthalate (PET), are widely used as food contact materials, textiles, and toys. However, their widespread use and potential for human exposure raise environmental and health concerns, particularly regarding the leaching of chemical additives. This study assessed hazardous plastic additives and non-intentionally added substances (NIAS) leached from paired virgin and recycled PET bottles (soda and water) purchased from Michigan and California and from textiles (toys, pillows, and clothing) acquired online or in stores in Michigan and Oregon. Results showed differences in contaminant profiles and concentrations between PET types and products. A total of 12 persistent, mobile, and toxic (PMT) additives, six organophosphate esters (OPEs), and 15 NIAS were detected. Notably, recycled PET (rPET) bottles consistently contained benzene, while virgin PET had higher ethylene glycol and 2-methyl-1,3-dioxolane levels. Additionally, OPEs were detected more frequently in rPET, indicating recycling as a contamination pathway. Geographically distinct contaminant profiles were evident, with Michigan bottles exhibiting elevated benzaldehyde, while California bottles showed higher diethylene glycol levels, suggesting differing manufacturing practices. Textiles exhibited distinct contamination profiles, highlighting a distinct exposure pathway for watersheds through laundry processes. Bioactivity assays with PET product extracts revealed moderate to high hormone receptor antagonism but no clear association with PET type, indicating potential hazardous effects from both virgin and recycled PET products. This study highlights the necessity of continued monitoring of contaminants in PET, including non-intentionally added substances and PMT plastic additives that are not currently regulated.

In the United States (U.S.), waste byproducts generated from the treatment of municipal waste (biosolids), production of livestock (livestock waste), and drilling of oil and gas wells (drilling waste) are commonly applied to agricultural lands. Although this can be a cost-effective reuse/disposal practice, there is limited research on the potential for contaminant exposures and effects on ecosystems, wildlife, and human health from such land applications. In this study, we conducted extensive chemical, microbial, and toxicity analyses of biosolid, livestock, and drilling wastes just prior to land application on agricultural lands at 34 sites across the U.S. Twenty-two analytical methods were used to determine potential contaminant exposures profiles for 452 organic and 114 inorganic chemicals, nine microbial groups, estrogenicity, and cytotoxicity. Analytical results document unique and substantial chemical, microbial, and toxicity profiles for these land-applied wastes. Of the three waste byproducts, biosolids contained the greatest concentrations of household chemicals, pesticides, pharmaceuticals, per-/polyfluoroalkyl substances, calcium, and phosphorus. Livestock waste contained the greatest concentrations of total and leachable dissolved organic carbon, biogenic hormones, mycotoxins, plant estrogens, total inorganic nitrogen, and potassium. Drilling waste contained the greatest concentrations of BTEX compounds (benzene, toluene, ethylbenzene, and xylenes), polycyclic aromatic hydrocarbons, rare-earth elements, barium, strontium, and uranium–thorium series radioisotopes. Biosolid and livestock wastes had greater culturable heterotrophic bacteria, halophilic bacteria, Escherichia coli (E. coli), enterococci, and staphylococci concentrations, and greater microbial diversity than drilling waste. Bioassay analyses indicated that exposure to contaminants in livestock wastes and biosolids could result in estrogenic effects, whereas exposure to contaminants in drilling waste could result in cytotoxic effects. Our study documents that current reuse/disposal practices for biosolid, livestock, and drilling wastes on agricultural lands could provide a potential pathway for the redistribution of unique and complex contaminant mixtures into the environment that have bioactive, endocrine disrupting, and carcinogenic characteristics. Results of this study provide a snapshot of chemical compositions and concentrations that can be used to inform the development of best-management practices to help maximize beneficial reuse of these wastes and minimize risk to the environment and human health.