Fate, behavior and effects of surfactants and their degradation products in the environment

Impact mechanisms of various surfactants on the biodegradation of phenanthrene in soil: Bioavailability and microbial community responses

The present study was conducted to systematically explore the mechanisms underlying the impact of various surfactants (CTAB, SDBS, Tween 80 and rhamnolipid) at different doses (10, 100 and 1000 mg/kg) on the biodegradation of a model polycyclic aromatic hydrocarbon (PAH) by indigenous soil microorganisms, focusing on bioavailability and community responses. The cationic surfactant CTAB inhibited the biodegradation of phenanthrene within the whole tested dosage range by decreasing its bioavailability and adversely affecting soil microbial communities. Appropriate doses of SDBS (1000 mg/kg), Tween 80 (100, 1000 mg/kg) and rhamnolipid at all amendment levels promoted the transformation of phenanthrene from the very slow desorption fraction (Fvslow) to bioavailable fractions (rapid and slow desorption fractions, Frapid and Fslow), assessed via Tenax extraction. However, only Tween 80 and rhamnolipid at these doses significantly improved both the rates and extents of phenanthrene biodegradation by 22.1-204.3 and 38.4-76.7 %, respectively, while 1000 mg/kg SDBS had little effect on phenanthrene removal. This was because the inhibitory effects of anionic surfactant SDBS, especially at high doses, on the abundance, diversity and activity of soil microbial communities surpassed the bioavailability enhancement in dominating biodegradation. In contrast, the nonionic surfactant Tween 80 and biosurfactant rhamnolipid enhanced the bioavailability of phenanthrene for degradation and also that to specific degrading bacterial genera, which stimulated their growth and increased the abundance of the related nidA degradation gene. Moreover, they promoted the total microbial/bacterial biomass, community diversity and polyphenol oxidase activity by providing available substrates and nutrients. These findings contribute to the design of suitable surfactant types and dosages for mitigating the environmental risk of PAHs and simultaneously benefiting microbial ecology in soil through bioremediation.

Electroactive biofilters outperform inert biofilters for treating surfactant-polluted wastewater by means of selecting a low-growth yield microbial community

Electrobioremediation is one of the most innovative disciplines for treating organic pollutants and it is based on the ability of electroactive bacteria to exchange electrons with electroconductive materials. Electroactive biofilters have been demonstrated to be efficient for treating urban wastewater with a low footprint; however, their application can be expanded for treating industrial wastewater containing significant concentrations (2.4 %vol) of commercial surfactants (containing lauryl sulfate, lauryl ether sulfate, cocamydopropyl betaine, and dodecylbenzene sulfonate, among others). Our electroactive biofilter outperformed a conventional inert biofilter made of gravel for all tested conditions, reaching removal rates as high as 4.5 kg COD/m3bed·day and withstood Organic Loading Rates as high as 9 Kg COD/m3·d without significantly affecting removal efficiency. The biomass accumulation reduced available bed volume in the electroactive biofilter just by 39 %, while the gravel biofilter decreased by 80 %. Regarding microbial communities, anaerobic and electroactive bacteria represented a substantial proportion of the total population in the electroactive biofilter. Pseudomonas was the dominant genus, while Cupriavidus, Shewanella, Citrobacter, Desulfovibrio, and Arcobacter were potential electroactive strains found in relevant proportions. The microbial community's composition might be the key to understanding how high removal rates can coexist with limited biomass production, making electroactive biofilters a promising strategy to overcome classical biofilter limitations.

Screening structure and predicting toxicity of pesticide adjuvants using molecular dynamics simulation and machine learning for minimizing environmental impacts

Surfactants as synergistic agents are necessary to improve the stability and utilization of pesticides, while their use is often accompanied by unexpected release into the environment. However, there are no efficient strategies available for screening low-toxicity surfactants, and traditional toxicity studies rely on extensive experimentation which are not predictive. Herein, a commonly used agricultural adjuvant Triton X (TX) series was selected to study the function of amphipathic structure to their toxicity in zebrafish. Molecular dynamics (MD) simulations, transcriptomics, metabolomics and machine learning (ML) were used to study the toxic effects and predict the toxicity of various TX. The results showed that TX with a relatively short hydrophilic chain was highly toxic to zebrafish with LC50 of 1.526 mg/L. However, TX with a longer hydrophilic chain was more likely to damage the heart, liver and gonads of zebrafish through the arachidonic acid metabolic network, suggesting that the effect of surfactants on membrane permeability is the key to determine toxic results. Moreover, biomarkers were screened through machine learning, and other hydrophilic chain lengths were predicted to affect zebrafish heart health potentially. Our study provides an advanced adjuvants screening method to improve the bioavailability of pesticides while reducing environmental impacts.

Innovative strategy for the effective utilization of coal waste slag in the Fenton-like process for the degradation of trichloroethylene

In response to environmental concerns at the global level, there is considerable momentum in the exploration of materials derived from waste that are both sustainable and eco-friendly. In this study, CS-Fe (carbon, silica, and iron) composite was synthesized from coal gasification slag (CGS) and innovatively applied as a catalyst to activate PS (persulfate) for the degradation of trichloroethylene (TCE) in water. Scanning electron microscope (SEM), fourier transmission infrared spectroscopy (FTIR), energy dispersive x-ray spectroscopy (EDS), brunauer, emmet, and teller (BET) technique, and x-ray diffractometer (XRD) spectra were employed to investigate the surface morphology and physicochemical composition of the CS-Fe composite. CS-Fe catalyst showed a dual nature by adsorption and degradation of TCE simultaneously, displaying 86.1% TCE removal in 3 h. The synthesized CS-Fe had better adsorption (62.1%) than base material CGS (36.4%) due to a larger BET surface area (770.8 m2 g-1), while 24.0% TCE degradation was recorded upon the activation of PS by CS-Fe. FTIR spectra confirmed the adsorption and degradation of TCE by investigating the used and fresh samples of CS-Fe catalyst. Scavengers and Electron paramagnetic resonance (EPR) analysis confirmed the availability of surface radicals and free radicals facilitated the degradation process. The acidic nature of the solution favored the degradation while the presence of bicarbonate ion (HCO3-) hindered this process. In conclusion, these results for real groundwater, surfactant-added solution, and degradation of other TCE-like pollutants propose that the CS-Fe composite offers an economically viable and favorable catalyst in the remediation of organic contaminants within aqueous solutions. Further investigation into the catalytic potential of coal gasification slag-based carbon materials and their application in Fenton reactions is warranted to effectively address a range of environmental challenges.

Effects of α-olefin sulfonate (AOS) on Tubifex tubifex: toxicodynamic-toxicokinetic inferences from the general unified threshold (GUTS) model, biomarker responses and molecular docking predictions

We investigated the potential ecological risks and harm to aquatic organisms posed by anionic surfactants such as α-olefin sulfonate (AOS), which are commonly found in industrial and consumer products, including detergents. This study assessed acute (96-h) and subchronic (14-day) responses using antioxidant activity, protein levels, and histopathological changes in Tubifex tubifex exposed to different AOS concentrations (10% of the LC50, 20% of the LC50, and a control). Molecular docking was used to investigate the potential interactions between the key stress biomarker enzymes (superoxide dismutase, catalase, and cytochrome c oxidase) of Tubifex tubifex. Acute AOS exposure showed a concentration-dependent decrease in survival, and the general unified threshold (GUTS) model revealed that survivorship is linked to individual response patterns rather than random (stochastic) fluctuations. The GUTS model also revealed dose-dependent toxicity patterns in Tubifex tubifex exposed to α-olefin sulfonate (AOS), with adaptive mechanisms at lower concentrations but significant increases in mortality beyond a certain threshold, emphasizing the role of the AOS concentration in shaping its toxicological impact. Exposure to AOS disrupted antioxidant activity, inducing oxidative stress, with GST and GPx showing positive associations with surfactant concentration and increased lipid peroxidation (elevated MDA levels); moreover, AOS exposure decreased protein concentration, signifying disturbances in vital cellular processes. Histopathological examinations revealed various tissue-level alterations, including cellular vacuolation, cytoplasmic swelling, inflammation, necrosis, and apoptosis. Molecular docking analysis demonstrated interactions between AOS and enzymes (-catalase, superoxide dismutase, and cytochrome c oxidase) in Tubifex tubifex, including hydrophobic and hydrogen bond interactions, with the potential to disrupt enzyme structures and activities, leading to cellular process disruptions, oxidative stress, and tissue damage. According to the species sensitivity distribution (SSD), the difference in toxicity between Tilapia melanopleura (higher sensitivity) and Daphnia magna (low sensitivity) to AOS suggests distinct toxicokinetic and toxicodynamic mechanisms attributable to more complex physiology in Tilapia and efficient detoxification in Daphnia due to its smaller size.

A comparative study of surfactant distribution and fate (western and eastern) Egyptian Mediterranean coasts focusing on its environmental toxicity

One of the most difficult-to-manage new contaminants constantly released into the environment is linear alkylbenzene sulphonate (LAS), an anionic surfactant. Significant volumes of LAS are received by the Mediterranean coast of Egypt. The current study is a comprehensive assessment of the environmental fate of the LAS 1505 km off the Mediterranean coast of Egypt in the fall of 2023 in order to track its geographic spread and eventual demise in the water column. Critical analysis of LAS revealed that it is vertically distributed in various ways according to sources, uses, production amounts, and salinity levels. The vertical variation of LAS can be explained by its amphiphilic structure. A significant increase in surfactant concentration (>300 μg/L) was recorded in 66% and 43% of the total samples, ranging from 301.128 to 455.36 and from 304.556 to 486.135 for the western and eastern sides along the Egyptian Mediterranean coast, respectively. Evaluation of the average acute and chronic risk quotient (RQ) along the investigated locations revealed that fish were the most susceptible to LAS in both long and short exposure periods. The presented results also indicated significant LAS toxicity to three trophic levels (RQ values > 1). LAS toxicity to marine organisms was greater in the western than in eastern coastal regions according to acute and chronic mixture risk characterization ratios (RCRmix). The three trophic levels in the study area had the following order of acute relative contribution (RC) to LAS toxicity: fish > invertebrates > algae. The ANOVA test results showed that in both the western and eastern regions, LAS varied significantly (p < 0.05) with salinity (1.04E-60 and 5.44E-42) and depth (6.02E-65 and 1.59E-47), respectively. In addition, a significant difference was observed using the ANOVA test between the eastern and western regions of the Egyptian Mediterranean coast.

Adsorption behavior and the potential risk of As(V) in soils: exploring the effects of representative surfactants

Arsenic contamination in soils poses a critical global challenge, yet the influence of surfactants on arsenic adsorption behavior is often underestimated. This study aims to investigate the effects of three representative surfactants, namely cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), and polyethylene glycol anhydrous sugar alcohol monooleate (Tween 80), on arsenic adsorption behavior in soils. The adsorption isotherm shifts from a single Temkin model without surfactants to both the Langmuir and Temkin models in the presence of surfactants, indicating the simultaneous occurrence of monolayer and multilayer adsorption for arsenic in soils. Moreover, the surfactants can inhibit the adsorption and hasten the attainment of adsorption equilibrium. SDS displayed the most inhibitory effect on arsenic adsorption, followed by Tween 80 and CTAB, due to the competitive adsorption, electrostatic interaction, and hydrophobic interaction. Variations in zeta potential with different surfactants further elucidate this inhibitory phenomenon. Through orthogonal experiment analyses, pH emerges as a primary factor influencing arsenic adsorption in soils, with surfactant concentration and type identified as secondary factors. Temperature notably affects CTAB, with the adsorption inhibition rate plummeting to a mere 0.88% at 50 °C. Sequential extraction analysis revealed that surfactants enhanced the bioavailability of arsenic. The FTIR, XRD, SEM, and CA analyses further support the mechanism underlying the effect of surfactants on arsenic adsorption in soil. These analyses indicate that surfactants modify the composition and abundance of functional groups, hinder the formation of arsenic-containing substances, and improve soil compactness, smoothness, and hydrophilicity. This study provides valuable insights into the effect of surfactants in arsenic-contaminated soils, which is often ignored in previous work.

Mechanisms of the novel pesticide sodium dodecyl benzene sulfonate in the mitigation of protozoan ciliated pathogens during microalgal cultivation

Protozoan ciliates represent a common biological contaminant during microalgae cultivation, which will lead to a decline in microalgae productivity. This study investigated the effectiveness of sodium dodecyl benzene sulfonate (SDBS) in controlling ciliate populations within microalgae cultures. SDBS concentrations of 160 mg/L and 100 mg/L were found to effectively manage the representative species of ciliates contamination by Euplotes vannus and Uronema marinum during the cultivation of Synechococcus and Chlorella, and the growth vitality of microalgae has been restored. Additionally, SDBS at these concentrations reduced oxidative stress resistance and induced membrane damage to remove biological pollutants by modulating enzyme activity, affecting lipid, energy, amino acid metabolism pathways, and processes such as translation and protein folding. This research provides insights into the mechanisms through which SDBS effectively combats protozoan ciliates during the microalgal cultivation. This contributes to reduce biological pollution, ensure the overall productivity and healthy and sustainable management of microalgae ecosystems.

Foam control in lakes and sewage receiving water bodies: A pre-emptive approach using decentralized inline water treatment design

Hideous and persistent foams on surface water bodies are global issues with far-reaching environmental consequences. This study examines Bellandur Lake (Bengaluru, India) plagued by foam since 2005 due to surfactant-laden untreated sewage ingress. Bellandur Lake receives 258 million liters of inadequately treated sewage daily, constituting 47% of its total volume. Yearlong water quality monitoring reveals that a) high surfactant levels (up to 17.8 ± 1 ppm) and b) prevalent anoxic conditions at lake inlets. Laboratory experiments show that controlled aeration achieved >90% surfactant degradation within 30 h at 3.5 ppm of dissolved oxygen conditions, indicating the need for an aeration chamber design based on the required residence time for inline water treatment. Based on these findings, a design of an inline wastewater treatment system to be installed at sewage entry points into the lake is presented in this work. The inline system was based on experimentally validated BioWin software. Simulations show that recirculating sludge enhances treatment efficiency, achieving effective surfactant degradation in 20 h (2/3rd original time) of residence time. Predictions suggest <1 ppm surfactant levels in the receiving water body, meeting local discharge norms to prevent frothing. This holistic approach, proposed for the first time, could serve as a blueprint for managing foam-related challenges in other waterbodies, offering insights into design, stakeholder engagement, and process optimization.

Transcriptomic changes in barley leaves induced by alcohol ethoxylates indicate potential pathways of surfactant detoxification

Hardly anything is known regarding the detoxification of surfactants in crop plants, although they are frequently treated with agrochemical formulations. Therefore, we studied transcriptomic changes in barley leaves induced in response to spraying leaf surfaces with two alcohol ethoxylates (AEs). As model surfactants, we selected the monodisperse tetraethylene glycol monododecyl (C12E4) ether and the polydisperse BrijL4. Barley plants were harvested 8 h after spraying with a 0.1% surfactant solution and changes in gene expression were analysed by RNA-sequencing (RNA-Seq). Gene expression was significantly altered in response to both surfactants. With BrijL4 more genes (9724) were differentially expressed compared to C12E4 (6197). Gene families showing pronounced up-regulation were cytochrome P450 enzymes, monooxygenases, ABC-transporters, acetyl- and methyl- transferases, glutathione-S-transferases and glycosyltransferases. These specific changes in gene expression and the postulated function of the corresponding enzymes allowed hypothesizing three potential metabolic pathways of AE detoxification in barley leaves. (i) Up-regulation of P450 cytochrome oxidoreductases suggested a degradation of the lipophilic alkyl residue (dodecyl chain) of the AEs by ω- and β- oxidation. (ii) Alternatively, the polar PEG-chain of AEs could be degraded. (iii) Instead of surfactant degradation, a further pathway of detoxification could be the sequestration of AEs into the vacuole or the apoplast (cell wall). Thus, our results show that AEs lead to pronounced changes in the expression of genes coding for proteins potentially being involved in the detoxification of surfactants.

Porous superabsorbent composites prepared from aqueous foam template and application evaluation

Rapid water absorption is very important for the application of superabsorbent polymers under dry or semi-dry conditions, but there are currently few relevant studies. In this context, a novel porous superabsorbent of chitosan-grafted acrylic copolymer-2-acrylamido-2-methylpropanesulfonic acid/sapindus mukorossi pericarp/calcined oil shale semi-coke (CS-g-P(AA-co-AMPS)/SMP/COSSC) was prepared by a green and convenient foam template method, which was triggered by redox polymerization. The rich pore structure of the porous superabsorbent was conducive to accelerating the water absorption rate. It only took 15 min to reach a swelling capacity of 650 g g-1 in distilled water. Soil experiments show that even with the addition of 0.5 wt% porous superabsorbent, the soil water retention time can be extended to 7 days. Finally, it was applied to the growth of cabbage seeds and it was found that the growth was significantly improved. Based on these excellent properties, we expect to provide a valuable reference for the preparation of fast-absorbing materials through the green water-based foam template method, contributing to sustainable agriculture.

Emerging contaminants and their potential impacts on estuarine ecosystems: Are we aware of it?

Emerging contaminants (ECs) are becoming more prevalent in estuaries and constitute a danger to both human health and ecosystems. These pollutants can infiltrate the ecosystem and spread throughout the food chain. Because of the diversified sources and extensive human activities, estuaries are particularly susceptible to increased pollution levels. A thorough review on recent ECs (platinum group elements, pharmaceuticals and personal care products, pesticides, siloxanes, liquid crystal monomers, cationic surfactant, antibiotic resistance genes, and microplastics) in estuaries, including their incidence, detection levels, and toxic effects, was performed. The inclusion of studies from different regions highlights the global nature of this issue, with each location having its unique set of contaminants. The diverse range of contaminants detected in estuary samples worldwide underscores the intricacy of ECs. A significant drawback is the scarcity of research on the toxic mechanisms of ECs on estuarine organisms, the prospect of unidentified ECs, warrant research scopes.

Trends and Age-Period-Cohort Effect on Incidence of Male Breast Cancer from 1980 to 2019 in Taiwan and the USA

Although male breast cancer (MBC) is globally rare, its incidence significantly increased from 1990 to 2017. The aim of this study was to examine variations in the trends of MBC incidence between populations in Taiwan and the USA from 1980 to 2019. The Taiwan Cancer Registry database and the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute of the USA were used. The age-standardized incidence rate was calculated using the world standard population in 2000. The long-term trends of the age, time period, and birth cohort effect on MBC incidence rates were estimated using the SEER Age-Period-Cohort Web Tool. The results revealed that the incidence of MBC in both countries increased from 2010 to 2019 (Taiwan: average annual percentage change (AAPC) = 2.59%; USA: AAPC = 0.64%). The age and period effects on the incidence rates in both countries strengthened, but the cohort effect was only identified in Taiwan (Rate ratio: 4.03). The identified cohort effect in this study bears resemblance to that noted in a previous investigation on female breast cancer in Taiwan. This suggests the possible presence of common environmental factors influencing breast cancer incidence in both genders, such as a high fat diet and xenoestrogen.

Method validation and environmental monitoring of triethanolamine ester quaternary ammonium compounds

In this study water and sediment samples, collected from the River Nene (Northamptonshire) at several sites in the vicinity of the Great Billing sewage treatment plant (STP), were analysed for triethanolamine quaternary compounds (TEAQ, ester quats). A method was developed using liquid chromatography tandem mass spectrometry (LC/MS/MS) with a electrospray ionisation source (ESI). Ten components were determined using a characterised commercial sample of Tallow TEAQ as a standard. To our knowledge this is the first time environmental concentrations of a wide spectrum of individual homologues of TEAQ have been reliably quantified covering a broad range of environmental matrices (STP influent, STP effluent, surface waters and sediments), due to the challenging nature of the analytical method. The method featured novel solutions for the determination of long and multiple chain length alkyl quats, controlling loss processes, background contamination and chromatographic performance. TEAQ compounds were found to be highly removed in the sewage treatment plant resulting in low effluent concentrations. Low concentrations in both river water and sediment samples were found also. In many cases levels were below the Method Detection Limit (MDL). In river water samples, mean values of TEAQ compounds found were 210-398 ng/L for C16:0/C18:0 TEAQ diester and 126-287 ng/L for C18:0/C18:0 TEAQ diester. River sediment was found to contain mean TEAQ levels of 7.07-12.5, 19.7 to 40.3 and 7.04-35.1 μg/kg dry weight for C16:0/C16:0, C16:0/C18:0, and C18:0/C18:0 TEAQ, respectively. At Great Billing STP monoesters and diesters of TEAQ were shown to be efficiently removed (>97 and 99 %, respectively), although limited samples were taken on this occasion.

Amide/Amino-Based Functional Additives for Lubricants: Structure, Antimicrobial Activity and Wear Resistance

The lubricating properties of the lubricants were tested under boundary friction conditions; it was found that the surface-active additives had reduced the wear mark and thus the value of the Goz/40 parameter (limiting load of wear). The introduction of a surfactant containing amide compounds into the oils and greases was highly effective in slowing down the oxidation process. Lubricants containing mono-15 ([3-(N,N,N-dimethylbuthylamine)propyl]hexadecanamide chloride) and 15-4-15 (tetramethylene-bis [3-(N,N,N-dimethylamine)propyl]hexadecanamide) additives were characterised by higher oxidation stability compared to the unmodified lubricants. Both of the analysed substances showed bactericidal properties against Staphylococcus aureus and Salmonella enteritica. Tests of antibacterial activity in the lubricants with the addition of mono-15 and 15-4-15 confirmed that these lubricants can be considered bactericidal against Gram-positive and Gram-negative bacteria.

Surfactant-Mediated Effects on Hydrological and Physical Soil Properties: Data Synthesis

Soils are under the threat of a multitude of anthropogenic factors affecting the complex interplay of various physical and hydrological soil processes and properties. One such factor is the group of surface-active compounds. Surfactants have a broad range of applications and can reduce solid-liquid interfacial forces and increase wettability and dispersion of particles. Surfactant effects are context-dependent, giving rise to a wide range of reported effects on different soil processes and properties. Here, we evaluate the evidence base of surfactant research on 11 hydrological and physical soil variables. Our goal was to identify knowledge gaps and test the robustness of the proposed surfactant effects. We found that the current knowledge base is insufficient to reach strong data-backed conclusions about the effects of surfactants in soils. We identified a unique case of bias in the data as a result of conflated patterns from laboratory and field studies. We could not support the hypothesis that the surfactant charge determines soil effects for any of the tested soil variables. We believe that further experiments on surfactant-mediated effects on soil properties and processes are urgently required, paying attention, in particular, to improving experimental design and data reporting standards.

Environmental contaminants modulate transport activity of zebrafish (Danio rerio) multidrug and toxin extrusion protein 3 (Mate3/Slc47a2.1)

Zebrafish Mate3 is one of six co-orthologs of human multidrug and toxin extrusion proteins. It is highly expressed in the kidneys, intestine, testes, and brain of males. Initial interaction studies showed its interaction with xenobiotic compounds, suggesting a role in the efflux of toxic compounds. In this study, we aimed to test various environmental contaminants for their interaction with zebrafish Mate3. We developed a stable zebrafish Mate3 cell line and optimized a high-throughput screening assay using DAPI and ASP+ as fluorescent model substrates. To gain insight into the structure and function of the Mate3 protein and relate these to the results of the DAPI and ASP+ transport measurements, we predicted its 3D structure using the AlphaFold2 algorithm. A 3D structure with high per residue confidence scores with 13 transmembrane segments (TMs) was obtained, with topology and mutual positioning characteristic of the Mate protein family in a shape open to the extracellular part. Molecular docking methods were used to identify DAPI and ASP+ binding sites on the surface and in the center of the protein cavity. Because our kinetics experiments combined with molecular docking indicated that there may be additional active sites in zebrafish Mate3, additional cytotoxicity experiments were performed and highly potent Mate3 interactors were identified from a set of 55 different environmental contaminants. Our results suggest that some of the identified interactors may be of environmental concern, as their interaction with Mate3 could lead to an impairment of its normal efflux function, making fish more sensitive to harmful substances commonly released into the aquatic environment. Finally, the quality of zebrafish Mate3 structures predicted by the AlphaFold2 algorithm opens up the possibility of successfully using this tool for in silico research on transport preferences of other Mate proteins.

Photoelectrocatalytic Surfactant Pollutant Degradation and Simultaneous Green Hydrogen Generation

For the first time, we demonstrate a photoelectrocatalysis technique for simultaneous surfactant pollutant degradation and green hydrogen generation using mesoporous WO3/BiVO4 photoanode under simulated sunlight irradiation. The materials properties such as morphology, crystallite structure, chemical environment, optical absorbance, and bandgap energy of the WO3/BiVO4 films are examined and discussed. We have tested the anionic type (sodium 2-naphthalenesulfonate (S2NS)) and cationic type surfactants (benzyl alkyl dimethylammonium compounds (BAC-C12)) as model pollutants. A complete removal of S2NS and BAC-C12 surfactants at 60 and 90 min, respectively, by applying 1.75 V applied potential vs RHE to the circuit, under 1 sun was achieved. An interesting competitive phenomenon for photohole utilization was observed between surfactants and adsorbed water. This led to the formation of H2O2 from water alongside surfactant degradation (anode) and hydrogen evolution (cathode). No byproducts were observed after the direct photohole mediated degradation of surfactants, implying its advantage over other AOPs and biological processes. In the cathode compartment, 82.51 μmol/cm2 and 71.81 μmol/cm2 of hydrogen gas were generated during the BAC-C12 and S2NS surfactant degradation process, respectively, at 1.75 V RHE applied potential.

Risks of benzalkonium chlorides as emerging contaminants in the environment and possible control strategies from the perspective of ecopharmacovigilance

An unprecedented increase in the use of disinfection products triggered by the coronavirus disease 2019 (COVID-19) pandemic is resulting in aggravating environmental loads of disinfectants as emerging contaminants, which has been considered a cause for worldwide secondary disasters. This review analyzed the literature published in the last decade about occurrence, bioaccumulation, and possible environmental risks of benzalkonium chlorides (BKCs) as emerging contaminants. Results indicated that BKCs globally occurred in municipal wastewater, surface water, groundwater, reclaimed water, sludge, sediment, soil, roof runoff, and residential dust samples across 13 countries. The maximum residual levels of 30 mg/L and 421 μg/g were reported in water and solid environmental samples, respectively. Emerging evidences suggested possible bioaccumulation of BKCs in plants, even perhaps humans. Environmentally relevant concentrations of BKCs exert potential adverse impacts on aquatic and terrestrial species, including genotoxicity, respiratory toxicity, behavioural effects and neurotoxicity, endocrine disruption and reproductive impairment, phytotoxicity, etc. Given the intrinsic biocidal and preservative properties of disinfectants, the inductive effects of residual BKCs in environment in terms of resistance and imbalance of microorganisms have been paid special attention. Considering the similarities of disinfectants to pharmaceuticals, from the perspective of ecopharmacovigilance (EPV), a well-established strategy for pharmaceutical emerging contaminants, we use the control of BKC pollution as a case, and provide some recommendations for employing the EPV measures to manage environmental risks posed by disinfectant emerging contaminants.

Maternal polysorbate 80 exposure causes intestinal ILCs and CD4+ T cell developmental abnormalities in mouse offspring

This study aimed to investigate the transgenerational impacts of maternal intake of polysorbate 80 (P80), an emulsifier widely used in modern society, on the development of offspring immunity. Our results revealed that maternal P80 treatment led to impaired differentiation of innate lymphoid cells (ILCs) and CD4+ T cells in the small intestinal lamina propria (SiLP), resulting in intestinal dyshomeostasis in female offspring. Furthermore, we found that SiLP ILCs abundances were significantly altered in 0-day-old fetuses from P80-treated mothers, indicating a prenatal impact of P80-treated mothers on offspring immunity. Additionally, cesarean section and foster-nursing studies demonstrated that P80-induced altered SiLP ILCs in 0-day-old fetuses could further induce dysregulation of ILCs and CD4+ T cells in the SiLP, thus promoting intestinal dysregulation in offspring later in life. Overall, our findings suggest that maternal P80 intake could prenatally program the development of offspring immunity, exerting a significant and long-lasting impact.

A review on the fate and effects of contaminants in biosolids applied on land: Hazards and government regulatory policies

The increase in world population growth and its resultant increase in industrial production to meet its need, have continued to raise the volume of wastewater received by treatment plant facilities. This has expectedly, led to an upsurge in the volume of sewage sludge and biosolids generated from wastewater treatment systems. Biosolids are best managed by application on land because of their agronomic benefits. However, this usage has been discovered to negatively affect humans and impact the environment due to the accumulation of minute concentrations of contaminants still present in the biosolid after treatment, hence the need for government regulations. This review article examined the fate and effects of pollutants, especially persistent organic pollutants (PoPs) of concern and emerging contaminants found in biosolids used for land applications, and also discussed government regulations on biosolid reuse from the perspectives of the two major regulations governing biosolid land application-the EU's Sludge Directive and USEPA's Part 503 Rule, in an attempt to draw attention to their outdated contents since enactment, as they do not currently meet the challenges of biosolid land application and thus, require a comprehensive update. Any update efforts should focus on USEPA's Part 503 Rule, which is less stringent on the allowable concentration of biosolid pollutants. Furthermore, an update should include specific regulations on new and emerging contaminants and persistent organic pollutants (PoPs) such as microplastics, pharmaceutical and personal care products (P&PCPs), surfactants, endocrine-disrupting chemicals, flame retardants, pathogens, and organic pollutants; further reduction of heavy metal standard limits, and consideration of soil phosphate-metal interactions to regulate biosolid agronomic loading rate. Future biosolid research should focus on the concentration of TCS, TCC, and emerging pharmaceuticals, as well as Microplastic transport in biosolid-amended soils, soil-plant transfer mechanism, and metabolism of PFAs in the soils; all of which will inform government policies on biosolid application on land.

Disclosing Environmental Ligands of L-FABP and PPARγ: Should We Re-evaluate the Chemical Safety of Hydrocarbon Surfactants?

Chemical contaminants can cause adverse effects by binding to the liver-fatty acid binding protein (L-FABP) and peroxisome proliferator-activated nuclear receptor γ (PPARγ), which are vital in lipid metabolism. However, the presence of numerous compounds in the environment has hindered the identification of their ligands, and thus only a small portion have been discovered to date. In this study, protein Affinity Purification with Nontargeted Analysis (APNA) was employed to identify the ligands of L-FABP and PPARγ in indoor dust and sewage sludge. A total of 83 nonredundant features were pulled-out by His-tagged L-FABP as putative ligands, among which 13 were assigned as fatty acids and hydrocarbon surfactants. In contrast, only six features were isolated when His-tagged PPARγ LBD was used as the protein bait. The binding of hydrocarbon surfactants to L-FABP and PPARγ was confirmed using both recombinant proteins and reporter cells. These hydrocarbon surfactants, along with >50 homologues and isomers, were detected in dust and sludge at high concentrations. Fatty acids and hydrocarbon surfactants explained the majority of L-FABP (57.7 ± 32.9%) and PPARγ (66.0 ± 27.1%) activities in the sludge. This study revealed hydrocarbon surfactants as the predominant synthetic ligands of L-FABP and PPARγ, highlighting the importance of re-evaluating their chemical safety.

The photolytic conversion of 4-nonylphenol to 4-nonylcatechol within snowpack of the Palisade Glacier, Sierra Nevada, CA, USA

4-Nonylphenol (4-NP), an environmental pollutant with potent ecotoxicological effects, has been discovered in significant quantities in glacial ice and snow of the Sierra Nevada Mountain Range, CA. Photolysis of 4-NP is suspected to be a major, if not the sole, breakdown pathway in snow. However, the photolysis process has yet to be characterized in detail for this unique environment. This study therefore seeks to (1) confirm the presence of the major photolysis product within snowpack and snowmelt samples from the Palisade Glacier, CA, (2) determine key photolysis parameters through laboratory assays in snow analogs, and (3) compute environmentally relevant photolysis rates in snowpack via a spectral solar irradiance model parameterized for the Palisade Glacier. The primary photooxidation product of 4-NP, 4-nonylcatechol (4-NC), was synthesized and characterized by NMR and GC-MS for use as a reference standard in the detection of 4-NC in environmental samples. 4-NP was detected in all snowpack (n = 4) and snowmelt (n = 5) samples, with concentrations of 1.05 (± 0.11) μg L^-1 and 1.28 (± 0.12) μg L^-1, respectively. 4-NC was detected in all snowmelt outflow samples and all but one snow samples (88 % detection frequency) but was below the limit of quantification for the given method. All samples were collected during a sampling regime at the Palisade Glacier in August of 2021. Quantum yields of photolysis at the 277 nm absorption band were determined to be 0.36 (±0.06) and 0.21 (±0.06) in ultrapure water and liquid snow, respectively. Under clear sky conditions at the Palisade Glacier, half-lives for 4-NP are estimated to range from 235 to 251 h (9.8-10.5 days) based on assays conducted in liquid snowmelt and irradiance modeling. These results suggest that the photolysis of 4-NP, and hence the production of 4-NC, is occurring at significant rates within the snowpack where 4-NC is inevitably released to downstream catchment areas via snowmelt. 4-NC is significantly more toxic than its precursor, thereby raising amplified concerns for downstream human and wildlife populations. Furthermore, the ubiquity of 4-NP among the Earth's environments presents this as an issue of potentially global concern.

Effect of ionic surfactants on the settling behavior of silt

Ionic surfactants are easily adsorbed by silt and clay particles, thus affecting the flocculation characteristics and settling behavior. The settling velocity, typical size, Zeta potential and surface tension of silt flocs were measured in the presence of two different kinds of ionic surfactants. The results indicated that the cetyltrimethylammonium bromide (CTAB, a typical cationic surfactant) can dramatically accelerate the settling of slit particles, while the linear alkylbenzene sulfonate (LAS, a typical anionic surfactant) slightly retarded silt sedimentation to some extent. In still water, the representative settling velocity dramatically increased from 0.36 cm s^-1 to 0.43 cm s^-1 with the increase of CTAB concentration, which increased by more than 20%. Oppositely, the sedimentation rate decreased from 0.36 cm s^-1 to 0.33 cm s^-1 with the increase of LAS concentration. In flowing water, as the flow rate increased from 0 to 20 cm s^-1 and the ionic surfactant concentration increased from 0 to 10 mg L^-1, the sedimentation rate decreased to 57% and 89% in the presence of CTAB and LAS respectively, which was due to an enhanced dispersion of silt particles and a breaking of flocs. The SEM image test shows that the floc particle size increased 1.5 times of the primary particle size under the high CTAB concentration. The flocculation induced by ionic surfactants greatly influences the sediment size as well as the law of settling velocity. The intrinsic influence mechanism was also discussed based on the variations of silt particle properties. This systematic study can be used for further development of flocculation models and particle size distribution of fine-grained soil.

Remediation of Surfactants Used by VUV/O3 Techniques: Degradation Efficiency, Pathway and Toxicological Analysis

Surfactants are increasingly used in systems that come into contact with the human body, such as food, pharmaceuticals, cosmetics and personal hygiene products. Increasing attention is being devoted to the toxic effects of surfactants in various human contact formulations, as well as the removal of residual surfactants. In the presence of ozone (O₃), anion surfactants-a characteristic micro-pollutant-such as sodium dodecylbenzene sulfonate (SDBS) in greywater, can be removed using radical advanced oxidation. Herein, we report a systematic study of the SDBS degradation effect of O₃ activated by vacuum ultraviolet (VUV) irradiation and the influence of water composition on VUV/O₃, and determined the contribution of radical species. We show a synergistic effect of VUV and O₃, while VUV/O₃ reached a higher mineralization (50.37%) than that of VUV (10.63%) and O₃ (29.60%) alone. The main reactive radicals of VUV/O₃ were HO•. VUV/O₃ had an optimal pH of 9. The addition of SO₄^2- had almost no effect on the degradation of SDBS by VUV/O₃, Cl^- and HCO₃^- slightly reduced the reaction rate, and NO₃^- had a significant inhibition on the degradation. In total, SDBS had three isomers, with which the three degradation pathways were very comparable. Compared with SDBS, the toxicity and harmfulness of the degradation by-products of the VUV/O₃ process decreased. Additionally, VUV/O₃ could degrade synthetic anion surfactants from laundry greywater effectively. Overall, the results show the potential of VUV/O₃ in safeguarding humans from residual surfactant hazards.

Degradation and transformation of linear alkyl-benzene sulfonates (LAS) in integrated constructed wetland-microbial fuel cell systems

Linear alkylbenzene sulfonates (LAS) are the most commonly-used anionic surfactants in cleaning agents and detergents. Taking sodium dodecyl benzene sulfonate (SDBS) as the target LAS, this study investigated the degradation and transformation of LAS in integrated constructed wetland-microbial fuel cell (CW-MFC) systems. Results showed that, SDBS was able to improve the power output and reduce the internal resistance of CW-MFCs by reducing transmembrane transfer resistance of organics and electrons because of the amphiphilicity and solubilization, however, SDBS with relatively high concentration had a great potential to inhibit electricity generation and organics biodegradation of CW-MFCs because of the toxic effects on microorganisms. C atoms on alkyl group and O atoms on sulfonic acid group of SDBS had greater electronegativity and were prone to oxidation reaction. The biodegradation of SDBS in CW-MFCs was a process of alkyl chain degradation, desulfonation and benzene ring cleavage in sequence via ω, β and/or α-oxidations and radical attacks under the action of coenzymes and oxygen, in which 19 intermediates were produced, including four anaerobic degradation products (toluene, phenol, cyclohexanone and acetic acid). Especially, for the first time cyclohexanone was detected during the biodegradation of LAS. The bioaccumulation potential of SDBS was greatly reduced through the degradation by CW-MFCs, and thus the environmental risk of SDBS was effectively reduced.

Quaternary ammonium compounds of emerging concern: Classification, occurrence, fate, toxicity and antimicrobial resistance

Amplified hygiene and precautionary measures are of utmost importance to control the spread of COVID-19 and future infection; however, these changes in practice are projected to trigger a rise in the purchase, utilisation and hence, discharge of many disinfectants into the environment. While alcohol-based, hydrogen peroxide-based, and chlorine-based compounds have been used widely, quaternary ammonium compounds (QACs) based disinfectants are of significant concern due to their overuse during this pandemic. This review presents the classification of disinfectants and their mechanism of action, focusing on QACs. Most importantly, the occurrence, fate, toxicity and antimicrobial resistance due to QACs are covered in this paper. Here we collated evidence from multiple studies and found rising trends of concern, including an increase in the mass load of QACs at a wastewater treatment plant (WWTP) by 331% compared to before the COVID-19 pandemic, as well as an increases in the concentration of 62% in residential dust, resulting in high concentrations of QACs in human blood and breast milk and suggesting that these could be potential sources of persistent QACs in infants. In addition to increased toxicity to human and aquatic life, increased use of QACs and accelerated use of antibiotics and antimicrobials during the COVID-19 pandemic could multiply the threat to antimicrobial resistance.

Glyphosate versus glyphosate based ionic liquids: Effect of cation on glyphosate biodegradation, soxA and phnJ genes abundance and microbial populations changes during soil bioaugmentation

The applicability of herbicidal ionic liquids (HILs) as an alternative form of herbicides is currently evaluated. Yet, the available research is lacking information on the behaviour of herbicidal ionic liquids upon addition to the environment, i.e., if cations and anions act as separate moieties or remain an ionic salt. Hence, we tested degradation of five HILs with the glyphosate anion, their bioavailability in soil, toxicity towards microorganisms, impact on the biodiversity and the abundance of phnJ and soxA genes. The cations were proven to be slightly or moderately toxic. The properties of cations determined the properties of the whole formulation, which might suggest that cations and anion act as the independent mixture of ions. The mineralisation efficiencies were in the range of 15-53%; however, in the case of cations (except non-toxic choline), only 13-20% were bioavailable for degradation. The hydrophobic cations were proven to be highly sorbed, while the anion was readily available for microbial degradation regardless of its counterion. The approach to enrich test samples with isolated microorganisms specialised in glyphosate degradation resulted in higher degradation efficiencies, yet not high enough to mitigate the negative impact of cations. In addition, increased activity of enzymes participating in glyphosate degradation was observed. In the view of obtained results, the use of cationic surfactants in HILs structure is not recommended, as sorption was shown to be determining factor in HILs degradation efficiency. Moreover, obtained results indicate that corresponding ions in HILs might act as separate moieties in the environment.

Evaluation of the Ecotoxicity of New Polyurethane Composites on Target Organisms for Aquatic and Atmospheric Environments

The present study investigated if new biocomposite materials, polyurethanes (PURs) added with functionalized cellulose fibers, produce potential toxic effects on two target organisms currently used in biomonitoring the quality of two different environmental compartments. Natural fibers were extracted from the species Spartium junceum L., a shrub commonly found in the southern region of the Mediterranean having a high cellulose content. All PURs produced were characterized by Fourier-transform infrared spectroscopy, and their structure was analyzed by scanning electron microscopy. We measured the effects of exposure to aromatic and aliphatic PUR composites (containing or not cellulose fibers) on the aquatic model organism Daphnia magna Straus, a freshwater crustacean (Cladocera), and a biomonitor of air quality, the fruticose epiphytic lichen Pseudevernia furfuracea (L.) Zopf. Leachates from aliphatic PUR composite not containing cellulose are more toxic to D. magna than all others, showing a slight acute toxicity in the case of the shortest exposure (24 h) and a moderate acute toxicity in the longer one (48 h). This effect is most likely due to the presence of free organic ammines and amides, which, in their turn, are immobilized in composites containing cellulosic fibers because of the considerable amount of chemical functional groups. Regarding lichens, both types of aliphatic PURs resulted in a toxic effect. Formulate not added with cellulose strongly promoted fungal peroxidation, whereas that which was functionalized affected the pigment concentration of the algal partner. Our results suggest that the use of cellulose in PUR production, in general, can limit the ecotoxicological effects on both test organisms and reduce the potential environmental impact due to this type of polymer. Environ Toxicol Chem 2023;42:421-436. © 2022 SETAC.

Widespread occurrence of quaternary alkylammonium disinfectants in soils of Hesse, Germany

Quaternary alkylammonium compounds (QAACs) are cationic organic compounds with amphiphilic properties that are widely used as surfactants and disinfectants in industry, households and agriculture. Several studies suggest that QAACs co-select for antibiotic resistant microorganisms and thus may contribute to the spread of antibiotic resistance in the environment. Data on QAAC occurrence in soil are scarce and limited to soils that are prone to direct exposure to QAACs. Therefore, we conducted a comprehensive study on the occurrence of QAACs in soils of Hesse, a federal state in Germany, covering an area of 21,115 km². Sixty-five soil samples that comprised different land uses (arable, grassland, forest, vineyard) and area types (rural, agglomeration) were analysed for concentrations of alkyltrimethylammonium (ATMACs, with alkyl chain lengths C8-C16), benzylalkyldimethylammonium (BACs, C8-C18) and dialkyldimethylammonium compounds (DADMACs, C8-C18) via HPLC-MS/MS after ultrasonic-assisted extraction with acidified acetonitrile. QAACs were detected in 97 % of the soil samples irrespective of land use and area type. The most abundant QAAC homologues were DADMACs > BACs > ATMACs. The highest total QAAC concentrations were detected in alluvial soils influenced by the deposition of suspended particles during flood events, with DADMAC-C16 and -C18 as the dominant homologues. The high abundance of long-chain DADMACs suggests that legacy pollution and accumulation govern QAAC concentrations in soils. The presence of QAACs in forest soils points to a potential input via atmospheric deposition. Our work highlights the widespread occurrence of QAACs in soils of Hesse and the need for more research on their entry paths and fate in the soil ecosystem.

Graphene quantum dots functionalised with rhamnolipid produced from bioconversion of palm kernel oil by Pseudomonas stutzeri BK-AB12MT as a photocatalyst

Methylene blue (MB) is a common organic dye found in textile wastewater and can harm the environment. Rhamnolipid-functionalized graphene quantum dots (RL-GQDs) are a newly developed eco-friendly photocatalyst to degrade MB. This photocatalyst is synthesized from graphene quantum dots (GQDs) and rhamnolipid. GQDs are already promising visible-light photocatalysts to degrade organic dyes. However, GQDs are not promising photocatalysts due to their reusability and photocatalytic performance. In this work, we used rhamnolipid to modify GQDs' structure and enhance their photocatalytic performance. The rhamnolipid used in this work was produced from bioconversion of palm kernel oil by mutated bacterial cells of Pseudomonas stutzeri BK-AB12MT. Meanwhile, GQDs were synthesized using the bottom-up method by pyrolysing citric acid. Transmission electron microscopy and Fourier-Transform Infrared spectroscopy were used to characterize these hybrid materials. These characterization techniques verified the formation of RL-GQDs. To prove the photocatalytic performance of RL-GQDs, we investigated the photocatalytic activity under visible light compared to some common photocatalysts, such as zinc oxide and titanium dioxide. Our findings showed that RL-GQDs could be applied as an eco-friendly photocatalyst to replace TiO₂ with a degradation efficiency of 59% ± 3% under visible light irradiation, higher than TiO₂.

New aspects of lipopeptide-incorporated nanoparticle synthesis and recent advancements in biomedical and environmental sciences: a review

The toxicity of metal nanoparticles has introduced promising research in the current scenario since an enormous number of people have been potentially facing this problem in the world. The extensive attention on green nanoparticle synthesis has been focussed on as a vital step in bio-nanotechnology to improve biocompatibility, biodegradability, eco-friendliness, and huge potential utilization in various environmental and clinical assessments. Inherent influence on the study of green nanoparticles plays a key role to synthesize the controlled and surface-influenced molecule by altering the physical, chemical, and biological assets with the provision of various precursors, templating/co-templating agents, and supporting solvents. However, in this article, the dominant characteristics of several kinds of lipopeptide biosurfactants are discussed to execute a critical study of factors affecting synthesis procedure and applications. The recent approaches of metal, metal oxide, and composite nanomaterial synthesis have been deliberated as well as the elucidation of the reaction mechanism. Furthermore, this approach shows remarkable boosts in the production of nanoparticles with the very less employed harsh and hazardous processes as compared to chemical or physical method-based nanoparticle synthesis. This study also shows that the advances in strain selection for green nanoparticle production could be a worthwhile and strong economical approach in futuristic medical science research.

Ecotoxicological Effects of the Anionic Surfactant Sodium Dodecyl Sulfate (SDS) in Two Marine Primary Producers: Phaeodactylum tricornutum and Ulva lactuca

Sodium Dodecyl Sulfate (SDS) is an anionic surfactant, extensively used in detergents, household and personal care products, as well as in industrial processes. The present study aimed to disclose the potential toxicological effects of SDS exposure under environmentally relevant concentrations (0, 0.1, 1, 3, and 10 mg L^-1) on the physiology and biochemistry (photosynthesis, pigment, and lipid composition, antioxidative systems, and energy balance) of two marine autotrophs: the diatom Phaeodactylum tricornutum and the macroalgae Ulva lactuca. A growth rate (GR) reduction in P. tricornutum was observed with a classic dose-response effect towards the highest applied concentration, while a GR increase occurred in U. lactuca. Regarding photochemistry, the decrease in the fluorescence of the OJIP curves and laser-induced fluorescence allowed a better separation between SDS treatments in U. lactuca compared with P. tricornutum. Although all pigments significantly decreased in U. lactuca at the highest concentrations (except for antheraxanthin), no significant variations occurred in P. tricornutum. On the other hand, changes in fatty acid content were observed in P. tricornutum but not in U. lactuca. In terms of classical biomarker assessment, a dose-effect relationship of individual biomarkers versus SDS dose applied; U. lactuca displayed a higher number of biomarker candidates, including those in distinct metabolic pathways, increasing its usefulness for ecotoxicological applications. By evaluating the potential application of optical and biochemical traits, it was evident that the fatty acid profiles of the different exposure groups are excellent candidates in P. tricornutum, concomitant with the characteristics of this anionic surfactant. On the other hand, the results presented by laser-induced fluorescence and some parameters of PAM fluorometry in U. lactuca may be an advantage in the field, offering non-invasive, fast, easy-to-use, high-throughput screening techniques as excellent tools for ecotoxicology assessment.

Production of Mannosylerythritol Lipids Using Oils from Oleaginous Microalgae: Two Sequential Microorganism Culture Approach

Mannosylerythritol lipids (MELs) are biosurfactants with excellent biochemical properties and a wide range of potential applications. However, most of the studies focusing on MELs high titre production have been relying in the use of vegetable oils with impact on the sustainability and process economy. Herein, we report for the first time MELs production using oils produced from microalgae. The bio-oil was extracted from Neochloris oleoabundans and evaluated for their use as sole carbon source or in a co-substrate strategy, using as an additional carbon source D-glucose, on Moesziomyces spp. cultures to support cell growth and induce the production of MELs. Both Moesziomyces antarcticus and M. aphidis were able to grow and produce MELs using algae-derived bio-oils as a carbon source. Using a medium containing as carbon sources 40 g/L of D-glucose and 20 g/L of bio-oils, Moesziomyces antarcticus and M. aphidis produced 12.47 ± 0.28 and 5.72 ± 2.32 g/L of MELs, respectively. Interestingly, there are no significant differences in productivity when using oils from microalgae or vegetable oils as carbon sources. The MELs productivities achieved were 1.78 ± 0.04 and 1.99 ± 0.12 g/L/h, respectively, for M. antarcticus fed with algae-derived or vegetable oils. These results open new perspectives for the production of MELs in systems combining different microorganisms.

Immobilization of mixed bacteria by novel biocarriers extracted from Cress and Chia seeds for biotreatment of anionic surfactant (SDS)-bearing real wastewaters

Selection of biocarrier type is an essential element for successful bacterial cells immobilization. The present investigation aimed to evaluate a novel application of Cress and Chia seeds as biocarriers for immobilization of mixed bacterial cells. Being an environmentally friendly, non-polluting, inexpensive, and non-toxic substances makes them promising biocarriers. On the other hand, there is an increasing concern about contamination by surfactants, sodium dodecyl sulfate (SDS) is among the most commonly used surfactant. The Cress and Chia seeds were cross-linked with PVA to prepare two types of beads; CrE-PVA and ChE-PVA, respectively. The beads were utilized for the SDS biodegradation in four kinds of actual SDS-bearing wastewaters originated from; carwash garage (CWW), laundry facility (LWW), and household detergent industry (HWW), in addition to domestic wastewater (DWW). The results revealed that maximum efficiencies of SDS elimination in DWW, LWW, HWW, and CWW were 98.12, 94.32, 93.04, and 99.08%, respectively, using CrE-PVA and 99.04, 94.96, 94.71, and 99.27%, respectively using ChE-PVA. Finally, both types of beads were recycled for five times without losing their stability and efficiency for SDS biodegradation. Four kinetic models were adopted which were Blackman, Monod, Haldane, and Teissier. Results revealed that Teissier model well fitted the experimental data.

Graywater treatment of emerging pollutant linear alkylbenzene sulfonate by adsorption with leather shave waste activated carbon

The purpose of this research is to evaluate the use of leather shave waste activated carbon (ACLW) as an alternative for the treatment of wastewater containing linear alkylbenzene sulfonate (LAS). Batch adsorption tests were carried out (pH effect, isotherms, kinetics). The activated carbon was tested for its life cycle by desorption with solvent and it was further evaluated as real wastewater treatment for bath graywater. Under the optimum pH of 2.5, kinetic studies showed a better correlation with the pseudo-second order model, with an activation energy of 27.5 kJ mol-1. Equilibrium isotherms correlated better with the double layer model, indicating hemi-micelle formation and performing a high-affinity isotherm. Adsorption was shown to be endothermic (∆H0 =  + 73.89 kJ mol-1), entropy driven (∆S0 =  + 0.46 kJ mol-1 K-1), and occurring spontaneously. The use of ethanol solution was effective for the regeneration of the adsorbent. Adsorption was applied in real wastewater, removing contaminants from bath graywater, especially anionic surfactants with up to 95% removal efficiency.

Death at the interface: Nanotechnology’s challenging frontier against microbial surface colonization

The emergence of antimicrobial-resistant bacterial strains has led to novel approaches for combating bacterial infections and surface contamination. More specifically, efforts in combining nanotechnology and biomimetics have led to the development of next-generation antimicrobial/antifouling nanomaterials. While nature-inspired nanoscale topographies are known for minimizing bacterial attachment through surface energy and physicochemical features, few studies have investigated the combined inhibitory effects of such features in combination with chemical alterations of these surfaces. Studies describing surface alterations, such as quaternary ammonium compounds (QACs), have also gained attention due to their broad spectrum of inhibitory activity against bacterial cells. Similarly, antimicrobial peptides (AMPs) have exhibited their capacity to reduce bacterial viability. To maximize the functionality of modified surfaces, the integration of patterned surfaces and functionalized exteriors, achieved through physical and chemical surface alterations, have recently been explored as viable alternatives. Nonetheless, these modifications are prone to challenges that can reduce their efficacy considerably in the long term. Their effectiveness against a wider array of microbial cells is still a subject of investigation. This review article will explore and discuss the emerging trends in biomimetics and other antimicrobials while raising possible concerns about their limitations and discussing future implications regarding their potential combined applications.

Highly Ca2+-Ion-Tolerant Biobased Zwitterionic Surfactant with High Interfacial Activity

The wide application of surfactants has a harmful effect on the environment, drawing more attention to the development and application of low-toxicity surfactants. A salt-tolerant and low-toxicity biobased zwitterionic surfactant, N,N-dimethyl-N-[2-hydroxy-3-sulfo-propyl]-N-benzyloxyoctadecanoyl-1,3-propanediamine (SPBOPA), was prepared from the oleic acid extracted from waste oils and anise ether extracted from the tarragon. The final surfactant structure was confirmed using gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS), and ¹H nuclear magnetic resonance (NMR) spectroscopy. The SPBOPA surfactant could reduce the interfacial tension between crude oil and formation brine to ultralow (5.2 × 10^-4 mN/m) at a low dosage without extra alkali. It still had good interfacial properties in NaCl up to 60 g/L, Ca²⁺ up to 2000 mg/L, and temperature up to 100 °C. Furthermore, SPBOPA had strong antidilution and antiadsorption properties with low toxicity as demonstrated by the high LD₅₀ value of >5000 mg/kg·BW. It could also enhance the wetting ability of crude oil surfaces. Meanwhile, it showed a high biodegradability in the environment. All of the results achieved in this work confirmed that the SPBOPA surfactant is a more robust and promising biobased surfactant candidate than traditional surfactants as an eco-friendly surfactant for enhanced oil recovery (EOR).

Enhancing extraction of alginate like extracellular polymers (ALE) from flocculent sludge by surfactants

Alginate like extracellular polymers (ALE) recovered from flocculent sludge has been identified as a kind of highly valuable biomaterials. However, the extraction protocols limit the production of biopolymers as ALE extracted from flocculent sludge is at a lower level, around 90-190 mg/g VSS. Under this circumstance, the eco-friendly and effective optimizations for the ALE extraction protocols are expected, and thus surfactants have gained an attention to enhancing the ALE extraction. With this study, different surfactants with different structures and chemical characteristics, such as sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB) and octyl phenyl polyoxyethylene ether (Triton X-100), were experimented to improve the ALE extraction, and in turn the optimal conditions and the associated mechanisms were evaluated and figured out. The experimental results indicated that surfactants could enhance the ALE extraction but also improve the alginate purification of ALE. With the optimal dosage of surfactants, the ALE extraction increased from 124.1 mg/g VSS to about 222.8-281.9 mg/g VSS, and the alginate purify was at around 54%-70%, in which the efficiency of the ALE extraction was improved by 79.5%-127.2%. Among others, Triton X-100 had the best performance on improving the ALE extraction, followed by CTAB and SDS. The mechanisms of surfactants on enhancing the ALE extraction and improving the alginate purify can be attributed to: i) surfactants micelles, which can solubilize flocs and extracellular biopolymers; ii) similar structures of surfactants and ALE, which follows the rule of "like dissolves like"; iii) functional groups adsorption, which facilitates the ALE release from matrixes. In a word, the optimized extraction protocol by using surfactants can be effectively applied to extract ALE from flocculent sludge.

Fate of 14C-labelled ionic organic chemicals in a water-sediment system and surface water

The persistence assessment of organic chemicals is based on neutral reference substances. Therefore, our study aimed at investigating the influence of a chemical charge on the degradation of organic compounds in a water-sediment system (OECD 308) and surface water (OECD 309). We used radiolabelled 4-n-dodecylbenzenesulfonic acid sodium salt (¹⁴C-DS^-, anionic), 4-n-dodecylbenzyltrimethylammonium chloride (¹⁴C-DA⁺, cationic) and 4-n-dodecylphenol (¹⁴C-DP, non-ionic) which are structurally similar except their charges. After 120 days of incubation in a water-sediment system, 68% (¹⁴C-DS^-), 6% (¹⁴C-DA⁺) and 63% (¹⁴C-DP) of the applied radioactivity (AR) were mineralized. The formation of non-extractable residues (NER) after 120 days was highest for ¹⁴C-DA⁺ (33% AR), followed by ¹⁴C-DS^- (19% AR) and ¹⁴C-DP (14% AR). Dissipation half-lives (DT₅₀) at 12 °C decreased as follows: ¹⁴C-DA⁺ (346 days) ≫ ¹⁴C-DS^- (47 days) > ¹⁴C-DP (30 days). After 60 days of incubation in surface water with suspended sediment, mineralization of ¹⁴C-DS^-, ¹⁴C-DA⁺ and ¹⁴C-DP accounted for 63%, 7% and 58% AR, respectively. Highest NER formation was observed for ¹⁴C-DP (21% AR), followed by ¹⁴C-DA⁺ (14% AR) and ¹⁴C-DS^- (9% AR). DT₅₀ (12 °C) decreased as follows: ¹⁴C-DA⁺ (45 days) > ¹⁴C-DP (3 days) > ¹⁴C-DS^- (2 days). We showed that a positive charge reduces the degradability of organic chemicals in both test systems. From a scientific point of view, simulation studies following OECD 309 should always be complimented by tests with high sorption capacity, e.g. OECD 308 and OECD 307 tests in order to assess the degradation of a compound, especially in case of cationic organic compounds.

An overview on surfactants as pollutants of concern: Occurrence, impacts and persulfate-based remediation technologies

Surfactants are molecules that reduce interfacial energy and increase solubility of other pollutants in water. These properties make them suitable for various domestic and industrial applications, soil remediation, pesticide formulation, among others. The increase in their use and the lack of strict regulations regarding their disposal and management is a matter of concern and requires more attention since the release and distribution of these compounds into the environment can modify important water quality parameters. As a result of these changes, different toxicological effects to aquatic organisms are discussed and exposed herein. On this basis, we provide an overview of the classes of surfactants, as well as their occurrence in different aqueous matrices. In addition, existing regulations around the world regarding their concentration limit for different environments are discussed. Current research focuses on the application of conventional treatments, such as biological treatments; notwithstanding, more toxic and bioaccumulative products can be generated. Advanced Oxidation Processes are promising alternatives and have also been widely applied for the removal of surfactants. This study provides, for the first time, an overview of the application of persulfate-based processes for surfactants degradation based on recent literature findings, as well as the various factors related to the activation of the persulfate anions. This review also highlights the challenges and opportunities for future research to overcome the obstacles to the practical application of this process.

Moesziomyces spp. cultivation using cheese whey: new yeast extract-free media, β-galactosidase biosynthesis and mannosylerythritol lipids production

Mannosylerythritol lipids (MELs) are biosurfactants with excellent biochemical properties and a wide range of potential applications. However, high production costs, low productivity and unsatisfactory scale-up production have hampered commercial adoption. Herein, we report for the first time the β-galactosidase production by Moesziomyces spp. from different sugars (D-galactose, D-glucose and D-lactose), with D-galactose being the best β-galactosidase inducer, with 11.2 and 63.1 IU/mgbiomass, for Moesziomyces aphidis 5535 T and Moesziomyces antarcticus 5048 T, respectively. The production of this enzyme allows to break down D-lactose and thus to produce MEL directly from D-lactose or cheese whey (a cheese industry by-product). Remarkably, when CW was used as sole media component (carbon and mineral source), in combination with waste frying oil, MEL productivities were very close (1.40 and 1.31 gMEL/L/day) to the ones obtained with optimized medium containing yeast extract (1.92 and 1.50 gMEL/gsusbtrate), both for M. antarcticus and M. aphidis. The low-cost, facile and efficient process which generates large amounts of MELs potentiates its industrialization.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13399-022-02837-y.

A Simplified Techno-Economic Analysis for Sophorolipid Production in a Solid-State Fermentation Process

Sophorolipids (SLs) are microbial biosurfactants with an important role in industry and a continuously growing market. This research addresses the use of sustainable resources as feedstock for bioproducts. Winterization oil cake (WOC) and molasses are suitable substrates for SLs via solid-state fermentation (SSF). The model proposed herein was established for annually processing 750 t of WOC and comparing three support materials: wheat straw (WS), rice husk (RH), and coconut fiber (CF). Production capacity ranged 325–414 t of SLs per year. Unit Production Cost was 5.1, 5.7, and 6.9 USD/kg SL for WS, RH, and CF production models, respectively, and was slightly lower with other substrates. Financial parameters were CAPEX 6.7 MM USD and OPEX 1.9 MM USD/y, with a NPV, IRR and payback time of 6.4 MM USD, 31% and 3.2 y, respectively. SLs recovery from the solid matrix was the major contributor to operating costs, while fermentation equipment shaped capital costs. Results show that the physical properties (bulk density, WHC) of substrates and supports define process costs beyond substrate purchase costs and process yields in SSF systems. To our knowledge, this is the first attempt to model SLs production via SSF at full scale for the economic valuation of the SSF process.

Surfactant Pollution, an Emerging Threat to Ecosystem: Approaches for Effective Bacterial Degradation

The use of surfactants in households and industries is inevitable and so is their discharge into the environment, especially into the water bodies as effluents. Being surface-active agents, their utilization is mostly seen in soaps, detergents, personal care products, emulsifiers, wetting agents, etc. Anionic surfactants are the most used class. These surfactants are responsible for the foam and froth in the water bodies and cause potential adverse effects to both biotic and abiotic components of the ecosystem. Surfactants are capable of penetrating the cell membrane and thus cause toxicity to living organisms. Accumulation of these compounds has been known to cause significant gill damage and loss of sight in fish. Alteration of physiological and biochemical parameters of water decreases the amount of dissolved oxygen and thus affecting the entire ecosystem. Microbes utilizing surfactants as substrates for energy form the basis of the biodegradation of these compounds. The main organisms for surfactant biodegradation, both in sewage and natural waters, are bacteria. Several Pseudomonas and Bacillus spp. have shown efficient degradation of anionic surfactants namely: sodium dodecyl sulphate (SDS), linear alkylbenzene sulphonate (LAS), sodium dodecylbenzenesulphonate (SDBS). Also, several microbial consortia constituting Alcaligenes spp., Citrobacter spp., etc. have shown efficacy in the degradation of surfactants. The biodegradation efficiency studies of these microbes/microbial consortia would be of immense help in formulating better solutions for the bioremediation of surfactants and help to reduce their potential environmental hazards.

Occurrence of alkylphenols and alkylphenol ethoxylates in North Sea sediment samples collected across oil and gas fields

Alkylphenol ethoxylates (APEs) have been used in several offshore oil and gas production applications including as emulsifiers in drilling mud formulations, which may have resulted in their disposal to sea. Despite concern over the endocrine disrupting potential of their alkylphenol (AP) degradation products, information on the presence of AP/APEs in marine sediments in the vicinity of oil and gas production facilities is scarce. This paper presents the occurrence of AP/APEs in marine sediment in North Sea oil and gas fields. The concentrations of octylphenol, nonylphenol and their ethoxylates near offshore installations were broadly comparable to, or higher than those of coastal and estuarine point source discharges. When compared to environmental assessment criteria, the NPCA Class V threshold values for octylphenol and nonylphenol were exceeded within 100 m and 500 m of infrastructure respectively, with higher concentrations of AP/APEs reported in fields that came online prior to 1986.

An introduction to the sources, fate, occurrence and effects of endocrine disrupting chemicals released into the environment

Many classes of compounds are known or suspected to disrupt the endocrine system of vertebrate and invertebrate organisms. This review of the sources and fate of selected endocrine disrupting chemicals (EDCs) in the environment includes classes of compounds that are "legacy" contaminants, as well as contaminants of emerging concern. EDCs included for discussion are organochlorine compounds, halogenated aromatic hydrocarbons, brominated flame retardants, per- and polyfluoroalkyl substances, alkylphenols, phthalates, bisphenol A and analogues, pharmaceuticals, drugs of abuse and steroid hormones, personal care products, and organotins. An exhaustive survey of the fate of these contaminants in all environmental media (e.g., air, water, soil, biota, foods and beverages) is beyond the scope of this review, so the priority is to highlight the fate of EDCs in environmental media for which there is a clear link between exposure and endocrine effects in humans or in biota from other taxa. Where appropriate, linkages are also made between the fate of EDCs and regulatory limits such as environmental quality guidelines for water and sediments and total daily intake values for humans.

Domestic wastewater in Indonesia: generation, characteristics and treatment

With a 270 million Indonesian population, domestic wastewater is one of the major contributors to wastewater generated from human activities. This review aimed to give an overview of the current state of domestic wastewater generation, characteristics and treatment systems in Indonesia. Overall, grey water quantity in Indonesia was 1 to 4 times higher than black water quantity, while the quantity of untreated grey water was 3 to 6 times higher than untreated black water. Parameters of concern include suspended solids, biochemical oxygen demand, chemical oxygen demand, oil and grease, nitrogen and coliforms. Our analysis shows that grey water can be a significant source of water pollution due to the large quantity and lack of treatment. In addition, black water treatment that relies mainly on on-site treatment is often inadequate due to the lack of quality control for the infrastructure, operation and maintenance. An incentive or penalty scheme to build and ensure the quality of domestic wastewater treatment is required and can be applied at the household, community or central (city) level.

Effects of anionic hydrocarbon surfactant on the transport of perfluorooctanoic acid (PFOA) in natural soils

The widespread usage of per- and polyfluoroalkyl substances (PFASs) has led to their ubiquitous co-existence with hydrocarbon surfactants in the subsurface environment. In this study, column experiments were conducted to investigate the effect of an anionic hydrocarbon surfactant (sodium dodecylbenzene sulfonate, SDBS, 1 and 10 mg/L) on the transport of perfluorooctanoic acid (PFOA) in two saturated natural soils under different cation type (Na⁺ and Ca²⁺) conditions. Results showed that SDBS (10 mg/L) significantly enhanced the transport of PFOA in two soils. This was likely because SDBS had a stronger adsorption affinity to the soils than PFOA, and can outcompete PFOA for the finite adsorption sites on the soil surface. The effect of SDBS on PFOA transport varied greatly in the two soils. More negatively charged soil surface and greater soil particle size likely contributed to the more noticeable transport-enhancement of PFOA resulting from the presence of SDBS. Also, the enhancement effect of SDBS (10 mg/L) with Ca²⁺ on PFOA transport was more significantly than that with Na⁺. This was possibly due to the blocking effect of SDBS to the more positively charged soil surface induced by Ca²⁺. Findings of this study point out the importance of anionic hydrocarbon surfactants on PFOA transport when assessing its environmental risks and implementing remediation efforts.