Environmental Chemistry Letters最新文献

There are about 10 million new cases of cognitive impairment diseases yearly, affecting 50 million people worldwide. Cognitive impairment is partly explained by pollutant exposure, with air pollution as one of the risk factor for dementia. Here we review the relationships between cognitive impairment and pollutant exposure, with focus on pollutant types, the entry of pollutants into the brain, symptoms and therapeutical drugs. Pollutants comprise solid and particulate compounds, organic and inorganic pollutants, bacteria, biotoxins and viruses. Symptoms include oxidative stress, neuroinflammation, aberrant cell death, and effects on the gut-brain axis. Cognitive impairment could be cured and prevented with antioxidants, anti-inflammatory compounds, inhibitors and activators, probiotics, and a healthy lifestyle. We present epidemiological evidence linking pollutants to cognitive impairment, and underlying neurotoxicity mechanisms. The olfactory mucosa and olfactory bulb pathway appears as the major route for pollutants entry into the brain parenchyma, which explains the strong epidemiological link between airborne pollutants and cognitive impairment. Oxidative stress and neuroinflammation trigger aberrant programmed cell death, including autophagy, apoptosis, and ferroptosis.

Per- and polyfluoroalkyl substances, known as ‘forever pollutants’ due to their very high stability in ecosystems, are industrial contaminants of emerging health concern commonly found in water. Remediation is particularly challenging because existing water and wastewater treatment plants are not designed to remove these pollutants. Here we review methods for the removal of per- and polyfluoroalkyl substances, with focus on the use of cyclodextrins, the cage molecules that can capture smaller substances. We present classical methods and adsorbents such as granular activated carbons, ion exchange resins, advanced oxidation processes, electrochemical degradation, metal–organic frameworks, and membrane filtration. Cyclodextrin-based materials include cross-linked compounds, molecularly imprinted polymers, covalent organic frameworks, and silica hybrids. We describe the complex formed by inclusion of a per- and polyfluoroalkyl substance into a cyclodextrin. We compare the use of cyclodextrins with other removal methods. Cyclodextrins are cyclic oligosaccharides used to prepare polyfunctional materials by cross-linking, immobilization, coating, or self-assembly. Cyclodextrins-based materials are much more efficient for the remediation of per- and polyfluoroalkyl substances, because these cage molecules can be designed to recognize specifically pollutants. As a consequence, cyclodextrins-based materials display much higher adsorption coefficients, in the range of 10⁴—10⁶ L per Kg, compared to less than 10⁴ L per Kg for activated carbon.

Rare earth elements are sedimentary pollutants of increasing health concern, yet the effect of global warming on their bioavailability and toxicity is unknown. To test this, we applied the diffusive gradients in thin films technique to assess the bioavailability of 15 rare earth elements, including lanthanides and yttrium, in sediments at temperatures ranging from 0 to 40 °C. We modeled the ecotoxicological risk to aquatic organisms using the species sensitivity distribution–probabilistic risk assessment–inclusion–exclusion principle. Results show that the bioavailability of all rare earth elements decreases by 40% to 70% as temperature increases from 0 to 40 °C, indicating reduced mobility and enhanced sediment adsorption. Similarly, the calculated ecotoxicological risk is reduced from 1.75 to 0.08%. This is the first evidence of temperature-driven attenuation of rare earth element risk in sediments, suggesting that global warming should decrease the toxicity of some rare earth elements.

Polycyclic aromatic hydrocarbons are well-known pollutants, yet some apects of their osteotoxicity and neurotoxicity have not been reviewed. Here we review benzo[a]pyrene-induced osteotoxicity and neurotoxicity in fish and mammals, with focus on phenotypic changes, cell development, molecular signaling pathways, key gene expression, and epigenetic modifications. Benzo[a]pyrene impairs bone health by suppressing osteoblast formation, promoting bone resorption, and disrupting remodeling, primarily through dysregulation of key transcription factors and signaling pathways. In neural tissues, metabolically-activated benzo[a]pyrene generates reactive oxygen species, triggering oxidative stress, dysregulation of gene expression, mitochondrial dysfunction, altered neurotransmitter levels, and neuronal apoptosis. Benzo[a]pyrene induced multigenerational osteotoxicity in 42% of fish studies, but 0% in rodent studies. It induced multigenerational neurotoxicity in 25% of fish studies and 15% in rodent studies. Epigenetic modifications are a critical mechanism linking benzo[a]pyrene exposure to these multigenerational and transgenerational toxicity in bone and neural systems of both fish and rodents.

The accelerating climate change requires rapid techniques to both sequester carbon dioxide and recycle solid waste. Here we review the accelerated carbonation of fly ash from municipal solid waste with emphasis on carbonation methods, carbon dioxide sequestration capability, influence of carbonation on fly ash properties, fly ash as a cementitious material, non-conventional uses of fly ash, environmental and economic benefits, mixing with other waste materials, pilot and industrial applications, and limitations. We observe that the accelerated carbonation of fly ash allows for carbon dioxide capture of up to 0.24 g CO₂ per gram of ash, reduces heavy metal leaching, facilitates the reuse of stabilized ashes, and generates materials suitable for a wide range of uses. Limitations include possible pH-induced remobilization of toxic metals such as cadmium, chromium, and antimony.

Bioaerosols represent a major health issue because they contain viruses, bacteria, biological fragments or residues and fungal spores. Humans are exposed to nearly 10⁴ viable bacteria and 10⁴ viable fungi per cubic metre of indoor air. Here, we review bioaerosols with emphasis on their sources, behaviour, detection methods, mitigation, transmission, and photocatalytic disinfection. Disinfection methods include fibrous photocatalytic membranes with interception efficiency comparable to commercial masks and high bactericidal efficiency, Z-scheme and S-scheme heterojunctions-based materials, biofilms loaded with composite catalysts, and photocatalytic filters coupled with air ionizers. Bioaerosols inactivation reaches 99.99% in 4 h under ultraviolet light, and 99.3% in 14.1 s under visible light using advanced heterojunction photocatalysts.

Remediation of metal-contaminated soils by aqueous washing is actually done using synthetic surfactants, calling for safer alternatives such as biosurfactants. Here we tested coffee-based humic substances extracted from various composts for soil washing of agricultural, industrial and urban soils contaminated by heavy metals. Molecular-level characterization of humic substances was done by ¹³C-nuclear magnetic resonance and thermochemolysis gas chromatography-mass spectrometry. Following washing, we measured heavy metals displacement into humic substance suprastructures by inductively coupled plasma mass spectrometry. Humic substance molecular changes were observed by ultrahigh resolution Orbitrap mass spectrometry. Soil toxicity was studied using the Microtox® Aliivibrio fischeri bioluminescence system. Results show that metal removal reached 90% for antimony, 15% for copper, and 13% for zinc. Moreover, toxicity was reduced by up to 62% for industrial soils, 50% for urban soils, and 46% for agricultural soils. The metal removal could be explained by chelation with humic pentacyclic terpenes.

The use of fossil fuels in the aviation sector is accelerating global warming by emitting carbon dioxide into the atmosphere, calling for carbon neutral jet fuels. Unlike road transport, which is transitioning to electrification, aviation requires high-energy–density fuels, making liquid alternatives essential. Here we review the production of jet biofuels with emphasis on current production technologies, microbial engineering for lipid synthesis, catalytic conversion of lipids, and economic and life cycle assessment aspects. Microbial lipids, including free fatty acids, can be produced from various carbon sources such as sugars, lignocellulose, methane, methanol, and formate. Catalytic upgrading of lipids can be achieved by hydroprocessing, hydrodeoxygenation, hydrocracking, and hydroisomerization. Metabolic engineering strategies to enhance lipid biosynthesis include increasing the precursor supply, repressing β-oxidation, controlling fatty acid chain length, and applying systems-level optimization using flux balancing, biosensor-guided regulation, and evolutionary engineering. These strategies have enabled the production of 98.9 g lipids and 50 g free fatty acids per liter. Pichia pastoris employing methanol as a substrate can produce up to 23 g/L of free fatty acids. Catalytic upgrading via hydrodeoxygenation and hydrocracking achieves conversion efficiencies over 90% and jet fuel selectivity above 70%. Techno-economic and life cycle assessments indicate that microbial oil-based sustainable aviation fuels could be cost-competitive and environmentally favorable.