Hydrophobic Organic Pollutants Research Articles

Development of diffusive gradients in thin-films technique for monitoring polycyclic aromatic hydrocarbons in coastal waters

Addressing the challenge of accurately monitoring polycyclic aromatic hydrocarbons (PAHs) in aquatic systems, this study employed diffusive gradients in thin-films (DGT) technique to achieve methods detection limits as low as 0.02 ng L−1 to 0.05 ng L−1 through in situ preconcentration and determination of time-integrated concentrations. The efficacy of the developed DGT samplers was validated under diverse environmental conditions, demonstrating independence from factors such as pH (5.03–9.01), dissolved organic matter (0–20 mg L−1), and ionic strength (0.0001–0.6 M). Notably, the introduction of a novel theoretical approach to calculate diffusion coefficients based on solvent-accessible volume tailored for PAHs significantly enhanced the method’s applicability, particularly for organic pollutants with low solubility. Field deployments in coastal zones validated the DGT method against traditional grab sampling, with findings advocating a 4 to 7-day optimal deployment duration for balancing sensitivity and mitigating lag time effects. These results provide a sophisticated, efficient solution to the persistent challenge of monitoring hydrophobic organic pollutants in aquatic environments, broadening the scope and applicability of DGT in environmental science and providing a robust tool for researchers.

Peculiarities of the Diffusion Transfer of Hydrophobic Organic Pollutants in Natural Disperse Systems

Peculiarities of the Diffusion Transfer of Hydrophobic Organic Pollutants in Natural Disperse Systems

Mutual Effects and Uptake of Organic Contaminants and Nanoplastics by Lettuce in Co-Exposure.

Organic contaminants, such as pesticides and pharmaceuticals, are commonly found in agricultural systems. With the growing use of plastic products, micro- and nanoplastics (MNPs) are increasingly detected in these agricultural systems, necessitating research into their interactions and joint effects to truly understand their impact. Unfortunately, while there has been a long history of research into the uptake of organic pollutants by plants, similar research with MNPs is only beginning, and studies on their mutual effects and plant uptake are extremely rare. In this study, we examined the effects of three agriculturally relevant organic pollutants with distinctive hydrophobicity as measured by log KOW (trimethoprim: 0.91, atrazine: 2.61, and ibuprofen: 3.97) and 500 nm polystyrene nanoplastics on their uptake and accumulation by lettuce at two different salinity levels. Our results showed that nanoplastics increased the shoot concentration of ibuprofen by 77.4 and 309% in nonsaline and saline conditions, respectively. Alternatively, organic co-contaminants slightly lowered the PS NPs uptake in lettuce with a more pronounced decrease in saline water. These results underscore the impactful interactions of hydrophobic organic pollutants and increasing MNPs on a dynamic global environment.

A screening model for predicting the potential of soil colloids-enhanced leaching of hydrophobic organic contaminants to groundwater at contaminated sites

Modeling the fate and transport of organic pollutants at contaminated sites is critical for risk assessment and management practices, such as establishing realistic cleanup standards or remediation endpoints. Against the conventional wisdom that highly hydrophobic persistent organic pollutants (POPs) (e.g., polybrominated diphenyl ethers and polycyclic aromatic hydrocarbons) in surface soils are essentially immobile, mounting evidence has demonstrated the potential of these contaminants leaching into the groundwater, due to enhanced transport by soil colloids. Here, we develop a Colloids-Enhanced Transport (CET) model, which can be used as a simple screening tool to predict the leaching potential of POPs into groundwater, as mediated by soil colloids. The CET model incorporates several processes, including the release of POPs-bearing colloids into the porewater, the vertical transport of colloids and associated POPs in the vadose zone, the mixing of POPs-containing soil leachate with groundwater, and the migration of POPs-bearing colloids in saturated zone. Thus, using parameters that can be easily obtained (e.g., annual rainfall, soil type, and common hydrogeological properties of the subsurface porous media), the CET model can estimate the concentrations of POPs in the saturated zone from the observed POPs concentrations in surface or shallow subsurface zones. The CET model can also be used to derive soil quality standards or cleanup endpoints by back-calculating soil concentrations based on groundwater protection limits.

Bioaccessibility and health risk assessment of hydrophobic organic pollutants in soils from four typical industrial contaminated sites in China

There have been reports of potential health risks for people from hydrophobic organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated hydrocarbons (PCHs), and organophosphate flame retardants (OPFRs). When a contaminated site is used for residential housing or public utility and recreation areas, the soil-bound organic pollutants might pose a threat to human health. In this study, we investigated the contamination profiles and potential risks to human health of 15 PAHs, 6 PCHs, and 12 OPFRs in soils from four contaminated sites in China. We used an in vitro method to determine the oral bioaccessibility of soil pollutants. Total PAHs were found at concentrations ranging from 26.4 ng/g to 987 ng/g. PCHs (0.27‒14.3 ng/g) and OPFRs (6.30‒310 ng/g) were detected, but at low levels compared to earlier reports. The levels of PAHs, PCHs, and OPFRs released from contaminated soils into simulated gastrointestinal fluids ranged from 1.74% to 91.0%, 2.51% to 39.6%, and 1.37% to 96.9%, respectively. Based on both spiked and unspiked samples, we found that the oral bioaccessibility of pollutants was correlated with their logKow and molecular weight, and the total organic carbon content and pH of soils. PAHs in 13 out of 38 contaminated soil samples posed potential high risks to children. When considering oral bioaccessibility, nine soils still posed potential risks, while the risks in the remaining soils became negligible. The contribution of this paper is that it corrects the health risk of soil-bound organic pollutants by detecting bioaccessibility in actual soils from different contaminated sites.

Effective adsorption of bisphenol A from water using cationic surfactant‐modified natural kaolin minerals

AbstractThe utilization of natural clay minerals for the adsorption of endocrine‐disrupting chemicals (EDCs) presents a cost‐effective and environmentally friendly approach. However, the hydrophilic nature of clay minerals' surface limits their efficacy in removing these hydrophobic pollutants. To overcome these limitations, this study employed two cationic surfactants, cetylpyridinium chloride (CPC) and cetyltrimethylammonium chloride (CTAC), to modify kaolin minerals to enhance their capacity to adsorb a specific type of EDCs, bisphenol A (BPA), and its analogs. The experimental results validated that the surfactant‐modified kaolin exhibited remarkable efficiency in removing BPA from water. The equilibrium adsorption capacities of CPC‐K and CTAC‐K for BPA were determined to be 11.4 mg/g (pH = 2.0–8.0) and 13.4 mg/g (pH = 2.0–6.5), respectively. Kinetic analysis revealed that the BPA adsorption followed a pseudo‐second‐order kinetic process, while isotherm analysis suggested that the BPA adsorption was better described by the Freundlich model (R2 = 0.993–0.998). The surfactant‐modified kaolin demonstrated a retention of over 70% of its initial adsorption capacity after five cycles of desorption and regeneration, further confirming its potential for recycling. Additionally, these modified adsorbents exhibited excellent compatibility in removing bisphenol analogs. These findings provide valuable insights into the practical application of surfactant‐modified clay minerals for the elimination of hydrophobic organic pollutants from water.

Major latex-like proteins show pH dependency in their binding to hydrophobic organic pollutants.

The Cucurbitaceae family accumulates hydrophobic organic pollutants in its aerial parts at high concentrations. Major latex-like proteins (MLPs) were identified in zucchini (Cucurbita pepo) as a transporting factor for hydrophobic organic pollutants. MLPs bind to hydrophobic organic pollutants in the roots, are secreted to xylem vessels as complexes, and are transported to the aerial parts. However, the suitable conditions for binding MLPs to hydrophobic organic pollutants remain elusive. In the present study, we show that MLPs bind to the hydrophobic organic pollutant pyrene with higher affinity under acidic conditions. Our results demonstrated that pH regulates the binding of MLPs to hydrophobic organic pollutants.

Enhancement of photodegradation of polyethylene with adsorbed polycyclic aromatic hydrocarbons under artificial sunlight irradiation

The photodegradation of plastic waste produces microplastics (MPs) in marine environments. Plastics can adsorb hydrophobic organic pollutants such as polycyclic aromatic hydrocarbons (PAHs) and can be transported over long distances. However, the impact of adsorbed pollutants on the photodegradation remains unknown. Here, we show that adsorbed PAHs act as photocatalysts that promote the photodegradation of polyethylene. Upon light irradiation, coloration and surface degradation of the PAH-adsorbed polyethylene sheets were observed, indicating that the PAH-adsorbed polyethylene sheets are less resistant to light. Furthermore, fluorene, phenanthrene, anthracene, benzo[a]anthracene, benzo[a]pyrene, and indeno[1,2,3-cd]perylene adsorbed on polyethylene MP exhibited lower photodegradation rates than the aqueous phase. These results indicate that these PAHs can act as photocatalysts; their role of PAHs may have two adverse effects on marine environment. First, enhanced photodegradation of plastic waste increased the production of MPs. Second, the lifetime of PAHs is extended, thereby enhancing PAHs pollution in marine environments.

Role of Gastrointestinal Microbiota from Crucian Carp in Microbial Transformation and Estrogenicity Modification of Novel Plastic Additives.

Ingestion is a major exposure route for hydrophobic organic pollutants in fish, but the microbial transformation and estrogenic modification of the novel plastic additives by the gut microbiota of fish remain obscure. Using an in vitro approach, we provide evidence that structure-related transformation of various plastic additives by the gastric and intestinal (GI) microbiota from crucian carp, with the degradation ratio of bisphenols and triphenyl phosphate faster than those of brominated compounds. The degradation kinetics for these pollutants could be limited by oxygen and cometabolic substrates (i.e., glucose). The fish GI microbiota could utilize the vast majority of carbon sources in a Biolog EcoPlate, suggesting their high metabolic potential and ability to transform various organic compounds. Unique microorganisms associated with transformation of the plastic additives including genera of Citrobacter, Klebsiella, and some unclassified genera in Enterobacteriaceae were identified by combining high-throughput genetic analyses and metagenomic analyses. Through identification of anaerobic transformation products by high-resolution mass spectrometry, alkyl-cleavage was found the common transformation mechanism, and hydrolysis was the major pathway for ester-containing pollutants. After anaerobic incubation, the estrogenic activities of triphenyl phosphate and bisphenols A, F, and AF declined, whereas that of bisphenol AP increased.

Influence of hydrodynamic conditions on the fate of halogenated flame retardants along salinity gradients in a highly polluted micro-tidal estuary

Halogenated flame retardants (HFRs) have properties similar to those of hydrophobic organic pollutants (HOPs). However, the understanding of their environmental fate in tidal estuaries remains limited. This study aims to bridge knowledge gaps regarding the land-sea transport of HFRs through riverine discharge into coastal waters. HFR levels were significantly influenced by tidal movement, and decabromodiphenyl ethane (DBDPE) was the predominant compound with a median concentration of 3340 pg L−1 in the Xiaoqing River estuary (XRE), whereas BDE209 had a median concentration of 1370 pg L−1. The Mihe River tributary plays a key role in transporting pollution to the downstream estuary of the XRE in summer, and the increasing suspended particulate matter (SPM) by resuspension in winter significantly affects HFR levels. These concentrations were inversely proportional to diurnal tidal oscillations. Tidal asymmetry caused an increase in SPM during an ebb tide, which increased HFR levels in a micro-tidal estuary such as the Xiaoqing River. The location of the point source and flow velocity influences the HFR concentrations during tidal fluctuations. Tidal asymmetry increases the likelihood of some HFRs being adsorbed by particles exported to the adjacent coast, and some settled down in areas with low hydrodynamic conditions, hindering their flow to the ocean.

Soil drying legacy does not affect phenanthrene fate in soil but modifies bacterial community response

Alteration of the structure of soil microbial communities following the elimination of hydrophobic organic pollutants (e.g., polycyclic aromatic hydrocarbons, PAHs) is generally assessed using DNA-based techniques, and soil is often required to dry prior to pollutant addition, to facilitate a better mix when establishing microcosms. However, the drying practice may have a legacy effect on soil microbial community structure, which would in turn influence the biodegradation process. Here, we used 14C-labeled phenanthrene to examine the potential side effects of precedent short-term drought events. The results indicate that the drying practice had legacy effects on soil microbial community structure, illustrated by irreversible shifts in the communities. The legacy effects had no significant impact on phenanthrene mineralization and non-extractable residue formation. However, they altered the response of bacterial communities to PAH degradation, leading to a decrease in the abundance of potential PAH degradation genes plausibly attributed to moderately abundant taxa. Based on a comparison of the varied effects of different drying intensity levels, an accurate description of microbial responses to phenanthrene degradation strongly relies on the establishment of stable microbial communities before PAH amendment. Concurrent alterations in the communities resulting from environmental perturbation could greatly mask minor alterations from the degradation of recalcitrant hydrophobic PAH. In practice, to minimize the legacy effects, a soil equilibration step with a reduced drying intensity is indispensable.

Remediation of soil contaminated with PAHs and γ-HCH using Fenton oxidation activated by carboxymethyl cellulose-modified iron oxide-biochar

The remediation of soil contaminated with hydrophobic organic pollutants has attracted great public concern. In the present study, a novel catalyst using biochar supported ferro ferric oxide modified by carboxymethyl cellulose (CMC-Fe3O4/BC) was developed to activate the Fenton reaction for hazardous hydrophobic organic pollutants, and the degradation mechanisms were analyzed in terms of free radicals, electron transfer pathways and degradation intermediates. The results showed that the CMC-Fe3O4/BC-activated H2O2 system degraded nearly 100% of pyrene in the aqueous system after a 1440-min reaction. The catalyst was also applied to remediate industrial field soil contaminated with PAHs and γ-HCH. The removal rate of the total pollutants reached 61.1% after a 10-day reaction, which was higher than that of Fe3O4/BC without modification. CMC enabled the Fe3O4 particles to more equably distribute on the BC surface, further effectively activating H2O2 to generate more ⋅OH and forming different degradation products compared to the Fe3O4/BC. Additionally, the CMC-Fe3O4/BC-activated H2O2 system obviously enhanced electron transfer on the BC surface. Thus, the PAHs and γ-HCH could be degraded via electron transfer pathways.

Effect of aging on polyethylene microfiber surface properties and its consequence on adsorption characteristics of 17alpha-ethynylestradiol.

This study assessed the interactive changes to the endocrine disruptor 17 alpha-ethynylestradiol (EE2) triggered by photoaging onto fibrous microplastics frequently found in the environment. The physicochemical property change of the polyethylene (PE) microfiber according to irradiation (i.e. 14 d UV-C (254 nm)) was studied through Fourier transform infrared spectroscopy, scanning electron microscope, and contact angle analysis. Additionally, the EE2 adsorption kinetics experiment was performed for the PE microfiber before and after UV irradiation to assess the change in adsorption characteristics. After UV irradiation, the PE microfiber surface roughness increased, the oxygen-containing functional group (e.g. carbonyl group) increased, and the contact angle (virgin PE: 80.02°, aged PE: 65.13°) decreased. A decrease in the surface hydrophobicity led to a decrease in the adsorption rate of EE2 (virgin PE: k = 0.0105 h-1, aged PE: not calculated). The hydrophobic interaction significantly affects the adsorption behavior of hydrophobic organic pollutants such as EE2 onto MPs, and continuous photo-aging of MPs may cause a new pattern of ecological risk. Therefore, there is a greater necessity for additional research relevant to this issue.

Sorption of bisphenol A onto microplastics and associated environmental risks in comparison to engineered carbonous materials and natural media

Microplastics (MPs) have been proven to be a vector for the migration of hydrophobic organic pollutants in the water system. However, the potential environmental risks of MPs compared with typical environmental materials are still unknown. In this work, the potential risks of MPs (high-density polyethylene (HDPE) and polyamide (PA)), engineered carbonous materials (active carbon (AC), graphene oxide (GO), and multi-walled nanotubes (MWCNTs)), and natural media (Soil and Sediment) were evaluated by comparing their interfacial behaviors to bisphenol A (BPA) under various environmental conditions. The maximum sorption capacities of BPA on those materials followed the order of AC (179 mg/g) > MWCNTs (73.5 mg/g) > PA (69.0 mg/g) > GO (44.1 mg/g) >> Soil (0.601 mg/g) > Sediment (0.164 mg/g) ≈ HDPE (0.163 mg/g). The main sorption mechanisms of BPA on GO were H-bonds and π-π interactions, while those on AC and MWCNTs were π-π interactions. Hydrophobic interaction played a dominant role in the sorption of BPA on Soil, Sediment, and HDPE, whereas PA bound to BPA primarily through H-bonds. Density functional theory (DFT) simulation also confirmed the predominant mechanism of hydrophobic interaction (−6.01 kcal/mol) between BPA and HDPE as well as H-bonds (−8.43 kcal/mol) between BPA and PA. Besides, solution pH, humic acid (HA), salinity, water matrices, and coexisting 17β-Estradiol (E2) played roles in the sorption of BPA. Based on the current abundance of carbonous materials and MPs in real environments, the calculated relative desorbed capacity (RDC) of BPA suggested that the predicted environmental risk of MPs was similar to that of engineered carbonaceous materials but much lower than that of natural media. Our findings highlight that the sorption behaviors and potential risks of MPs in real environments highly depend on the structural properties of MPs, in which surface functional groups are particularly important.

Determination of partition coefficients of phthalic acid esters between polydimethylsiloxane and water and its field application to surface waters

Phthalic acid esters (PAEs) or phthalates are endocrine-disrupting chemicals and among the most frequently detected hydrophobic organic pollutants, which can be gradually released from consumer products into the environment (e.g., water). This study measured the equilibrium partition coefficients for 10 selected PAEs, with a wide range of logarithms of the octanol-water partition coefficient (log Kow) from 1.60 to 9.37, between poly(dimethylsiloxane) (PDMS) and water (KPDMSw) using the kinetic permeation method. The desorption rate constant (kd) and KPDMSw for each PAEs were calculated from kinetic data. The experimental log KPDMSw for the PAEs ranges from 0.8 to 5.9, which is linearly correlated with log Kow values up to 8 from the literature (R2 > 0.94); however, it slightly deviated for the PAEs with log Kow values greater than 8. In addition, KPDMSw decreased with the temperature and enthalpy for PAEs partitioning in PDMS-water in an exothermic manner. Furthermore, the effects of dissolved organic matter and ionic strength on the partitioning of PAEs in PDMS were investigated. PDMS was used as a passive sampler to determine the aqueous concentration of plasticizers in river surface water. The results of this study can be used to evaluate the bioavailability and risk of phthalates in real environmental samples.

Ionic liquid-functionalized dendrimer grafted silica for mixed-mode chromatographic separation and online solid-phase extraction

The efficient sample pretreatment and high-performance chromatographic separation are essential for an accurate analysis of the complex sample. Finding a material that can apply as both sorbent for sample preparation and stationary phase for chromatography is greatly important for analytical chemistry. With a large number of active sites and designable properties, the dendrimers displayed potential performance for sample preparation and chromatographic separation. In order to improve its selectivity restricted by the limited type of functional groups (amide, ethylidene, amino groups), ionic liquid (1,1′-(1,4-butyricdiyl)bis(1-aminopropyl imidazolium)dibromide) were introduced to functionalize dendrimers. With porous silica as the base, ionic liquid-functionalized dendrimer grafted silica (SiO2@G1.5-IL) was obtained and characterized by X-ray photoelectron spectroscopy, elemental analyzer, as well as specific surface and porosity analyzer. The material was used as stationary phase for mixed-mode chromatography and sorbent for SPE, respectively. Under reversed-phase liquid chromatography (RPLC), it successfully separated some hydrophobic analytes (five polycyclic aromatic hydrocarbons (PAHs), two bisphenols, diphenylpropane, and diphenylmethane), by utilizing hydrophobic, π-stacking and hydrogen bonding interactions. Based on the hydrophilic effect, it could separate hydrophilic analytes (nucleosides and alkaloids), which coincident with hydrophilic interaction liquid chromatography (HILIC). And it exhibited better separation capacity than NH2@SiO2 and SiO2@G1.5 under the above two modes. Furthermore, the thermodynamic parameters (ΔH, ΔS, and ΔG) of the above types of analytes on the SiO2@G1.5-IL column were also investigated in detail, revealing the controlling factors during the chromatographic separation. And the relative standard deviations (RSDs, 0.03–2.95%, n = 10) of the repeatability of chromatographic separation were satisfactory. After that, SiO2@G1.5-IL-based SPE column was online combined with high-performance liquid chromatography to investigate the extraction selectivity for three types of hydrophobic organic pollutants (PAHs, estrogens, and bisphenols), and compared to SiO2 and C18 columns. According to their extraction performance, PAHs were selected as the target analytes, and the online analytical method was established. The limits of detection were as low as 0.001 μg L-1 due to the high enrichment factor reach to 3869, limits of quantity were 0.003–0.17 μg L-1, linear ranges were from 0.003 to 15.0 µg L-1, the adsorption capacity was 16.10 μg g−1, as well as RSDs were 0.5–3.7%, 0.6–6.7%, and 4.2–9.0% for intraday, interday tests and reproducibility. Finally, it was applied to analyze the environmental water samples (tap water, snow water, and rainwater), and satisfactory results were obtained (spiked recoveries were 86.8%-120.9%). Therefore, SiO2@G1.5-IL was a powerful material that can be used for the chromatographic separation of both hydrophobic and hydrophilic samples by RPLC or HILIC mode, as well as the efficient online extraction of hydrophobic targets prior to C18 column-based high-performance liquid chromatography.

Effects of polystyrene nanoplastics on melanin interference toxicity and transgenerational toxicity of ethylhexyl salicylate based on DNA methylation sequencing

Organic ultraviolet filters (OUVFs) are new hydrophobic organic pollutants in the aquatic environment. When ingested by aquatic organisms, OUVFs can induce a variety of toxic effects in organisms and be transferred to offspring. However, as the main active ingredient in sunscreens, OUVFs have rarely been investigated for their melanin interference toxicity or transgenerational toxic effects on aquatic organisms and their interactive toxic effects with nanoplastics (NPs). Here, we show the mechanism by which OUVFs interfere with melanogenesis in parental or offspring zebrafish and the effect of polystyrene (PS) NPs on the melanin-interference effect of OUVFs. We found that EHS induced significant enrichment of the melanogenesis pathway, inhibited the expression of the key melanin gene microphthalmia-associated transcription factor a (mitfa) and induced the mitf tyrosinase (tyr)-dopachrome tautomerase (dct)-tyrosinase related protein 1 (tyrp1) signaling cascade in parents, which ultimately induced a decrease in melanin content. After reproduction, transgenerational melanin interference effects of EHS may occur through the maternal inheritance of mitfa. Coexisting PS-NPs may inhibit the melanin interference toxicity or transgenerational toxicity of EHS by reducing ultraviolet irritation to the skin through adsorption of EHS. Our results demonstrate the ecotoxic potential of OUVFs in terms of melanin interference and the interference of PS-NP carrier effects on the toxicity of OUVFs. We anticipate that our assay will contribute to the assessment of the toxic effects of OUVFs and provide a basis for the interactive ecotoxicity assessment of PS-NPs and hydrophobic organic pollutants.

Evolution of pace-of-life syndrome under conditions of maternal PCB contamination and global warming in early life stages of cold stenothermic fish (Arctic char)

The end of the 20th century was characterised by rapid modifications of ecosystem functioning under different pressures (such as eutrophication and toxic pollution). Increasing temperatures in the context of global warming could have indirect consequences, such as increased bioavailability of hydrophobic organic pollutants amongst aquatic species. According to the “pace-of-life syndrome” (POLS) theory, these stressors could lead to covariations in many life traits. Lake Bourget is the largest natural lake in France and has been highly polluted from the fifties to the eighties both with a high load of nutrients (wastewater discharge) and polychlorinated biphenyls (PCBs) (industrial effluent discharge). Despite improvements in water quality since the 21st century, PCB levels are still higher than the United States Environmental Protection Agency cut-off for wildlife protection. The population of Arctic char, a cold stenothermic salmonid, has remained low in Lake Bourget for the last ten years despite restocking efforts and complete re-oligotrophication. We hypothesised that PCB pollution can affect the Arctic char population and that the increase in water temperature could magnify the effects of PCB. Thus, this study aimed to investigate the effects of maternal PCB contamination on offspring using a multiparametric and multiscale approach. Female Arctic char were contaminated with PCB before spawning, and each fertilised spawn was incubated at two temperatures (4 and 8.5 °C). The results showed that co-exposure to increased temperature and maternal PCB contamination influenced biodemographic, physiological, and behavioural parameters. The effects were highly dependant on the developmental stage. Based on the POLS theory, a continuum of life traits that may reflect potential physiological and behavioural modifications in response to these concurrent stressors is highlighted

Fire-resistant MXene composite aerogels for effective oil/water separation

Oil spills pose an enormous threat to marine ecosystems and human health, and, thus, arouse widespread concern. Physical adsorption is an effective and environmentally friendly method for remediation of oily wastewater. Finding absorbents with outstanding mechanical robustness, enduring superhydrophobicity, high absorption efficiency, and good regeneration capability remains challenging. In this paper, a hydrophobic composite aerogel (PDMS-Fe-MXene/A-HA) is fabricated using MXene nanosheets as a skeleton, artificial humic acid (A-HA) as a reinforcing phase, and polydimethylsiloxane (PDMS) as a hydrophobic modifier via an induced self-assembly process with a suitable Fe2+ crosslinking agent. Owing to the strong interaction between A-HA and MXene, the as-prepared PDMS-Fe-MXene/A-HA aerogel exhibits durable hydrophobicity (WCA=135°) and a highly efficient absorption capacity for a variety of hydrophobic organic pollutants (64–121 g g−1). Superelastic mechanical properties and excellent thermal stability endow the hybrid aerogel with good recyclability. The flux value for the PDMS-Fe-MXene/A-HA aerogel for an oil-water combination is determined to be 23478 L h−1 m2. Therefore, the new aerogel offers a viable alternative for successful oil/water separation.

Interactive neurotoxicity of environmentally relevant concentrations of polystyrene nanoplastics and butyl methoxydibenzoyl methane on early zebrafish embryos

Organic ultraviolet filters (OUVFs) and nanoplastics (NPs) are two important new pollutants that coexist widely in freshwater and coastal habitats. Both OUVFs and MPs can be taken up by aquatic organisms and may be toxic or co-toxic. In this study, the neurotoxicity and interaction neurotoxicity of the typical OUVFs butyl methoxydibenzoyl methane (BM-DBM) and polystyrene nanoplastics (PS-NPs) on zebrafish at environmental concentrations were comprehensively investigated at the tissue and molecular levels using transgenic or non-transgenic zebrafish. Results showed that both BM-DBM and PS-NPs induced abnormal expression of developmental genes neurogenin 1, glial fibrillary acidic protein, Finkel-Biskis-Jinkins osteosarcoma oncogene, growth-associated protein 43, synapsin IIa, and apoptosis regulator a (Bcl2a), Bcl2 associated x and apoptosis-related cysteine peptidase a, neuronal loss, motor neuron axon deletion, neuronal apoptosis and behavioral abnormalities in larvae thus being neurotoxic. BM-DBM also specifically interferes with neurotransmitter systems and affects signaling between neurons. In addition, PS-NPs and BM-BDM exerted synergistic and antagonistic effects in inducing apoptosis in neuronal cells and developmental neurotoxicity, respectively. Our results highlight the neurotoxic risk of PS-NPs and BM-BDM and the complex interactive neurotoxic effects of the two. We anticipate that our study may lay the foundation for ecological risk assessment of OUVFs and PS-NPs and exploration of complex interactions between PS-NPs and hydrophobic organic pollutants.