Environmental science. Advances最新文献

Soil organic matter (SOM) is a complex and heterogeneous molecular system, crucial for soil health and ecosystem functioning. Therefore, the release of pollutant molecules into the environment poses a significant environmental threat. Mechanisms that are governed by the interactions of these pollutants with SOM at the molecular level remain largely unexplored. In this study, coarse-grained molecular dynamics simulations were employed to investigate the behavior of hexachlorobenzene (HCB) and sulfanilamide (SAA) in humic substance (HS) systems with varying compositions. Diffusion coefficients indicated a strong influence of water on SAA, with SAA displaying higher mobility, whereas HCB exhibited greater accumulation in the HS phase. Calculations of spatial distributions supported these observations, showing that SAA is predominantly situated in the water phase, while HCB's interaction was influenced by the hydrophobicity of the SOM system. Simulations in the microsecond range, which were possible by the coarse-grained representation, revealed temporary trapping of SAA in the SOM matrix. These were anti-correlated with water diffusion, while HCB's behavior was dominated by direct pollutant–SOM interactions. In general, the coarse-graining approach provides novel insights into the trapping processes of pollutants in SOM and offers a realistic representation of molecular interactions at larger spatial and temporal scales. The proposed method enhances the understanding of pollutant mobility in soil systems, thus enabling future studies on the ecological impact of pollutant–SOM interactions.

Per- and polyfluoroalkyl substances (PFAS) are synthetic organic compounds characterized by strong C–F bonds and various functional groups, which contribute to their persistence and mobility in the aquatic environment. Bauxite residue (or red mud) is a highly alkaline waste from the aluminum industry, often stored in large quantities in tailing ponds. Recently, growing interest in sustainable waste management has highlighted the potential of bauxite residue to remove organic pollutants from water. This study investigates the use of activated bauxite residue (ABR) (produced via a reduction roasting process) as an adsorbent for a mixture of 10 PFAS substances in water. Bench-scale testing demonstrated that long-chain PFAS can be effectively removed by ABR (up to 100%) whereas the short-chain ones achieved 20–100% removal. PFAS removal using ABR follows a pseudo-second-order kinetic model, indicating that chemisorption may play a role during adsorption. This is further supported by the XPS analysis that shows the presence of metal–F bond. Isotherm study further indicated that at its current material characteristics (pore volume = 0.14 cm³ g⁻¹, BET surface area = 25 g m⁻², point of zero charge of ∼pH 5), high dosage of ABR (∼10 g L⁻¹) is required to reach >85% removal for ∑PFAS (n = 10). Cytotoxicity results supported the use of <10 g L⁻¹ ABR to minimize ABR toxicity and maximize PFAS removal. Although further material optimization is needed to lower dosage requirements and improve competitiveness with established adsorbents (e.g., powdered activated carbon), our preliminary results highlight the potential of ABR as a promising sorbent for PFAS removal.

Lithium is increasingly used in rechargeable batteries for mobile devices, electric vehicles, and energy storage, among other applications. One of the common formulations of lithium batteries is lithium nickel manganese cobalt oxide (LiNMC) particles. Increasing utilization of LiNMC batteries would require adequate disposal and/or recycling, and yet the potential disposal of lithium batteries as waste either in or outside of landfills might lead to toxic effects to people and wildlife. However, understanding of the potential toxicity of LiNMC particles is limited. Based on previous literature investigating the mechanisms of toxicity of the constituent metals, as well as lithium cobalt oxide (LCO) nanoparticles, we hypothesized that LiNMCs would cause toxicity via mitochondrial impairment and oxidative stress. We further hypothesized that LiNMC toxicity would be exacerbated by knockdown of frh-1 and gas-1, Caenorhabditis elegans orthologs of human mitochondrial disease genes frataxin and NDUFS2. Finally, we predicted that LiNMC exposure would cause developmental neurotoxicity. We tested these predictions by carrying out LiNMC exposures, and found these did not significantly impact the redox state, steady-state ATP levels, mitochondrial:nuclear DNA ratio, or oxygen consumption in worms exposed developmentally to amounts of LiNMC that caused mild growth inhibition. We discuss possible reasons for the difference between our results and previous publications, including particle size. Furthermore, while knockdown of frh-1 and gas-1 altered several parameters, knockdown of these genes did not increase or decrease the effects of LiNMCs. However, we did find that exposure to LiNMC caused degeneration of dopaminergic, cholinergic, glutamatergic, and GABAergic neurons, but not serotonergic neurons or glial cells. Interestingly, it appears that the developmental neurotoxicity was driven either by a particle-specific effect, or a component other than lithium, because exposure to lithium chloride at the same concentration had no effect.

The widespread incorporation of per- and polyfluoroalkyl substances (PFAS) in various daily-use items has garnered considerable attention regarding environmental and health hazards in the last decade. Among different categories of PFAS, a paradigm shift has occurred towards short-chain PFAS alternatives like GenX, ADONA, and F53B, driven by environmental considerations and regulatory changes. Exposure to PFAS can happen through consuming contaminated food and drink, inhaling contaminated dust, or skin contact with PFAS-containing objects. Furthermore, occupational exposure might result from manufacturing and firefighting operations employing fluorinated compounds. In humans and monkeys, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) exhibit an increased affinity for plasma proteins. However, the exact extent of this affinity is still a matter of research. The buildup of PFOS in the liver might cause injury or dysfunction by interfering with its regular operation. Compared to other human tissues, the liver has been shown to accumulate higher amounts of PFOS. Although there is an absence of epidemiological studies on PFOS, a possible connection between the health disorder and elevated cholesterol levels has been established by many researchers. Considering the transition as a future environmental burden, this review aims to bring together ongoing research compilations on short-chain PFAS, delving into their persistence, prevalence, and bioaccumulative toxicity in aquatic environments and focusing on critical areas of research gaps. An extensive literature analysis assessed the relative abundance of short-chain compounds compared to their long-chain counterparts within aquatic ecosystems. US EPA has setup new guidelines specifically for drinking water for PFOA and PFOS compounds which is 4 ppt. Furthermore, this review highlights emerging regulatory measures being implemented worldwide to safeguard public health. These measures encompass a range of strategies, from the European Union's emphasis on banning certain manufacturing and production practices under the REACH regulations to establishing exposure limits and disposal protocols in the United States.

Microplastic (MP) pollution in freshwater systems has emerged as a pressing environmental concern, yet our efforts on prioritizing key pathways remain obscure. One of the promising approaches to reduce MP emissions is identifying key pathways to reduce their emissions at the source. To this end, we investigated how major MP pathways like stormwater runoff, wastewater treatment plants (WWTPs), littering zones, and laundry facilities show distinct MP characteristics in response to continuous rainfall in a highly urbanized lake. Our findings spotlighted WWTPs as persistent MP hotspots, with continuous rainfall substantially increasing MP abundance near stormwater outfalls. Fibers were dominant near WWTP and laundry sites, while stormwater and littering sites were dominated by fragments, signifying pathway-specific characteristics. Black particles were observed only near stormwater outlets and confirmed as rubber derived from tire and road wear abrasion. Continuous rainfall also affected the chemical profiles, particularly near stormwater outlets, resulting in the appearance of new polymers like polyurethane (PU), acrylonitrile butadiene styrene (ABS), and polyvinyl chloride (PVC). Furthermore, diversity indices also proved the transformative nature of continuous rainfall in reshaping MP community composition, highlighting the complexity of MP pollution dynamics. The risk assessment identified stormwater and WWTP pathways as significant contributors to MP-related toxicity. Overall, the findings showed how extreme weather events like continuous rainfall play a critical role in changing MP dynamics in freshwater systems and spotlighted key pathways and the need for targeted interventions, especially improving stormwater management and wastewater treatment to mitigate MP pollution.

This research addresses a critical challenge in environmental sustainability: the remediation of contaminated wastewater in the Estero Salado, a vital ecosystem in Guayaquil, Ecuador. An innovative treatment strategy was employed using nitrifying bacteria, activated biomass and efficient microbial consortia. The study uniquely relied on real, non-simulated effluent and sediment samples, ensuring direct applicability of results. Significant reductions in nitrogenous compounds were achieved, particularly ammonia, approaching internationally allowed environmental thresholds. Nonetheless, persistent hydrocarbons and high chemical oxygen demand remained critical limitations, requiring further complementary treatments. Overall, the findings demonstrate the potential of biotechnology-based strategies for sustainable water remediation. This work provides a replicable approach for restoring highly polluted aquatic systems and underscores their positive implications for vulnerable coastal communities.

This study investigates the occurrence and distribution of fluoride in Iowa's groundwater and drinking water. Fluoride, added to community water supplies to prevent dental caries, can pose health risks at high concentrations. The U.S. Public Health Service recommends an optimal fluoride concentration of 0.7 mg L⁻¹, while the EPA sets a maximum contaminant level (MCL) at 4 mg L⁻¹ and a secondary MCL at 2 mg L⁻¹. This research analyzes fluoride data from various sources, including the Iowa Department of Natural Resources and the US Geological Survey, covering 9011 raw groundwater samples from 1931 and 2017 and 26 280 treated drinking water samples from 1934 to 2021. Fluoride concentrations in Iowa's groundwater ranged from <0.1 mg L⁻¹ to 11.2 mg L⁻¹, with an average of 0.65 mg L⁻¹ and a median of 0.35 mg L⁻¹. Approximately 69% of untreated raw source groundwater samples fell below the recommended 0.7 mg L⁻¹, while 7% exceeded the secondary MCL of 2 mg L⁻¹. Higher fluoride levels are associated with deeper wells and specific aquifers, such as the Cambrian-Ordovician and Mississippian. Treated public drinking water showed an average fluoride concentration of 0.87 mg L⁻¹, indicating a higher average of 0.24 mg L⁻¹ (mean) compared to untreated groundwater due to fluoridation practices. Fluoride concentrations in treated water peaked between 1980 and 1999, then declined slightly after 2000 and more so when systems began aligning with the 2015 recommendation to lower the optimal level to 0.7 mg L⁻¹. This pattern reflects how regulatory guidance and water source management have influenced fluoride levels over time. This study highlights significant regional variability in fluoride levels, influenced by aquifer lithology, well depth, and water chemistry. Anthropogenic sources also contribute to fluoride concentrations. The findings underscore the need for tailored water management strategies to balance the benefits of fluoridation with the risks of excessive fluoride intake. This research provides valuable insights for public health agencies, water suppliers, and residents, aiming to optimize fluoride levels in Iowa's drinking water to ensure safety and efficacy.

Per- and polyfluoroalkyl substances (PFASs), emerging contaminants with significant biotoxicity, are widely present in aquatic environments. This review analyzes PFAS removal technologies (including adsorption, oxidation techniques—electrochemical, photocatalytic, and sonolytic—biodegradation, and membrane separation), examining their mechanisms, effectiveness, advantages, disadvantages, and applicability. Adsorption remains the most prevalent method, effectively removing PFASs across various concentration levels. However, limitations include long adsorption cycle, difficulty in removing short-chain PFASs, and less-than-ideal regeneration capabilities, which drives ongoing exploration of novel adsorbent materials. Electrochemical, photocatalytic, and sonolytic degradation technologies offer high removal efficiency, short reaction times, the ability to degrade short-chain PFASs, and mineralization potential. Achieving complete mineralization, however, requires stringent reaction conditions, and high energy demands lead to significant operational costs. For biodegradation technology, the search for microorganisms with high PFAS mineralization capabilities and plant species with high PFAS accumulation capacity remains crucial. Consequently, developing low-cost, highly efficient, and widely applicable PFAS removal technologies is an urgent priority. Combining these technologies with other removal methods may be an important direction for future development.

As the environmental impact of per- and polyfluoroalkyl substances (PFAS) increases, understanding their deposition to soils near chemical industries is vital to mitigate health and ecological risks. Lyon (France) is a hub of chemical production and faces concerns about PFAS releases into the environment. This study assessed the extent of PFAS deposition from chemical industries located in central Lyon to different parts of Lyon. Through a target analysis using UHPLC-MS, we investigated the concentration of 80 PFAS in 215 Lyon soil samples collected around a fluoropolymer industrial complex. PFAS contamination of eggs in Lyon has been reported by local public health; hence, we evaluated PFAS in soils from a few selected chicken-feeding areas and free-range chicken eggs. High PFAS concentrations (3.8–175 μg kg⁻¹) were observed in soils near fluorochemical industries, with levels declining as distance from the industrial site increased. Long-chain PFCAs (C ≥ 8) and PFSAs (C ≥ 6) showed high detection rates (78–100%), with PFUnDA (0.05–106 μg kg⁻¹), PFTrDA (0.03–47.6 μg kg⁻¹), PFOS (0.1–32.6 μg kg⁻¹), PFHxS (0.03–23.7 μg kg⁻¹), PFNA (0.02–13.4 μg kg⁻¹) and PFOA (0.05–6.8 μg kg⁻¹), being the predominant PFAS. The ∑14 PFAS detected in soils from chicken-feeding areas ranged from 3.3–10.5 μg kg⁻¹ and 2.1–19.1 μg kg⁻¹ in eggs. This confirmed that the chickens are exposed to PFAS from the surrounding soils and other sources through their diet and foraging. Generally, the detection of elevated levels of PFNA, PFUnDA, and PFTrDA suggests an industrial input from the production of Surflon® at the Pierre-Bénite site. A significant negative correlation (p-value < 0.001) was observed between PFAS concentrations across the zones and their distance from the chemical industry. The variability in PFAS distribution may be influenced by wind direction, which has likely transported airborne PFAS from its source near the industrial complex and extending towards other parts.

The analysis of seventeen years (2001–2017) of satellite and MERRA-2 model data products demonstrates the influence of seasonal variability of aerosols on Indian summer monsoon rainfall and Aerosol Direct Radiative Forcing (ADRF) at the Top of the Atmosphere (TOA) as well as at the Surface (SFC) during El-Niño/Southern Oscillation (ENSO) events over South Asia. In order to understand the ENSO influence, deviations were quantified from normal years to El-Niño (E_dev) and La-Niña (L_dev) years. This study investigated greater spatial variability of net ADRF at the TOA (−3 to +3 W m⁻²) and at the SFC (−5 to +6 W m⁻²) during the JJAS season during El-Niño years over northwest India, Himalayan region and central India compared to La-Niña years. It is interesting to note that the magnitude of ADRF is highly variable during the post-monsoon season at both the SFC and TOA. The radiative forcing at the SFC varies significantly, more than (±) 10 times the mean during pre-monsoon season. An important observation is the negligible deviation of radiative forcing (L_dev)at the TOA particularly in the post-monsoon season. Moreover, this study also demonstrates and compares the seasonal variability of aerosols with radiative forcing and their effect on summer monsoon rainfall quantification by using a statistical multiple regression model.