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With wide use of nanoparticles, co-exposure of aquatic organisms to nanoparticles and organic pollutants often takes place in the environment. However, the combined effects are still rarely understood. In this study, in order to study the interaction and biological effects of nanoscale zero-valent iron (nZVI) and linear alkylbenzene sulfonate (LAS), which acts as a typical surfactant, the freshwater algae Scenedesmus obliquus was exposed to nZVI and LAS individually and in combination for 96 h. According to the inhibition rate of the algae, the toxic effects were investigated by dose-response analysis. Then the combined effect of nZVI and LAS was evaluated using three evaluation models including toxicity unit (TU), additional index (AI), and mixture toxicity index (MTI). The results showed that the 96 h IC50 of nZVI and LAS to Scenedesmus obliquus was 2.464 mmol L−1 and 0.332 mmol L−1, respectively. When nZVI coexisted with LAS at toxic ratio 1:1, the 96 h IC50 value was 1.658 mmol L−1 (shown with nZVI), and the partly additive effect of nZVI mixed with LAS was confirmed. However, when the toxic ratio of nZVI:LAS was 4:1, it showed synergistic effect. In addition, when nZVI mixed with LAS at toxic ratio 1:4, the joint effect is antagonistic effect. In addition, the content of chorophyll in Scenedesmus obliquus, especially the content of chlorophyll a, was decreased with the increase of mixture dose. However, the protein levels did not show significant changes at different mixture doses.

Surfactants belong to a group of chemicals that are well known for their cleaning properties. Their excessive use as ingredients in care products (e.g., shampoos, body wash) and in household cleaning products (e.g., dishwashing detergents, laundry detergents, hard-surface cleaners) has led to the discharge of highly contaminated wastewaters in aquatic and terrestrial environment. Once reached in the different environmental compartments (rivers, lakes, soils, and sediments), surfactants can undergo aerobic or anaerobic degradation. The most studied surfactants so far are linear alkylbenzene sulfonate (LAS), quaternary ammonium compounds (QACs), alkylphenol ethoxylate (APEOs), and alcohol ethoxylate (AEOs). Concentrations of surfactants in wastewaters can range between few micrograms to hundreds of milligrams in some cases, while it reaches several grams in sludge used for soil amendments in agricultural areas. Above the legislation standards, surfactants can be toxic to aquatic and terrestrial organisms which make treatment processes necessary before their discharge into the environment. Given this fact, biological and chemical processes should be considered for better surfactants removal. In this review, we investigate several issues with regard to: (1) the toxicity of surfactants in the environment, (2) their behavior in different ecological systems, (3) and the different treatment processes used in wastewater treatment plants in order to reduce the effects of surfactants on living organisms.

Caffeine (CAF) and linear alkylbenzene sulfonate (LAS) are human activity indicators, classified as contaminants of emerging concern (CECs). The long-term effects of these CECs on keystone species are still scarce in the literature. In this study, the molting and reproduction of Daphnia magna were evaluated over chronicle experiments by quantitative and qualitative approaches. The reported environmental concentrations (scenario 1) of CAF (0.005, 0.03, and 0.127 mg L−1) and LAS (0.4, 1.0, and 2.5 mg L−1) did not show statistical differences in molting process. Inhibition for molting index (%IM) was observed in expected effect concentration exposures (scenario 2) to CAF (20, 40, and 60 mg L−1) and LAS (4.1, 4.5, and 4.9 mg L−1). A decrease in the number of offspring (17 to 30%) and anticipation of the release time of the first four broods were observed in exposures to CAF. Moreover, LAS increased the offspring number produced per D. magna in the 1st (33 to 40%) and 2nd (22 to 52%) broods, in addition to a reduction of the time between 2nd and 3rd broods. Evidence of offspring induction in offspring index (%IO) was observed in exposures to LAS in scenario 1 and inhibition was recorded for scenario 2 (all LAS concentration and 60 mg L−1 of CAF). In scenario 2, for CAF and LAS, caused an inhibition on %IO and a significant decrease in the total offspring produced, especially on the 2nd brood (from 26 to 48%). These findings suggest that the D. magna life cycle may be impacted by a wide range of doses of environmentally relevant pollutants, whereas different approaches support interpreting the level of damage to daphnids’ reproduction and development.

Real textile wastewater containing high salinity (up to 12.6 g·kg−1) and surfactant (up to 5.9 mg·L−1 of linear alkylbenzene sulfonate – LAS) was submitted to biological treatment for colour (up to 652 mg Pt-Co·L−1) and sulphate (up to 1,568.6 mg SO4−2·L−1) removal. The influence of ethanol and molasses supplementation was firstly evaluated in anaerobic batch reactors for the removal of dyes and sulphate. Subsequently, aiming to remove aromatic amines (dye degradation by-products), an anaerobic–aerobic continuous system supplemented with molasses was applied. Supplementation had no influence on colour removal (maximum efficiencies around 70%), while it improved sulphate reduction (23% without supplementation against 87% with supplementation), and conferred robustness to the reactors, which recovered quickly after higher salinity impact. The aerobic reactor removed aromatic amines when the level of surfactants was lower than 1.0 mg LAS·L−1, but the performance of the system was hindered when the concentration was increased to 5.9 mg LAS·L−1. Findings suggest that the supplementation of an easily biodegradable organic matter might be a strategy to overcome wastewater fluctuation in composition.

This paper presents measurements of the scintillation light yield and time profile for a number of concentrations of water-based liquid scintillator, formulated from linear alkylbenzene (LAB) and 2,5-diphenyloxazole (PPO). We find that the scintillation light yield is linear with the concentration of liquid scintillator in water between 1 and 10% with a slope of 127.9 ± 17.0 ph/MeV/concentration and an intercept value of 108.3 ± 51.0 ph/MeV, the latter being illustrative of non-linearities with concentration at values less than 1%. This is larger than expected from a simple extrapolation of the pure liquid scintillator light yield. The measured time profiles are consistently faster than that of pure liquid scintillator, with rise times less than 250 ps and prompt decay constants in the range of 2.1–2.85 ns. Additionally, the separation between Cherenkov and scintillation light is quantified using cosmic muons in the CHESS experiment for each formulation, demonstrating an improvement in separation at the centimeter scale. Finally, we briefly discuss the prospects for large-scale detectors.

Multivariate statistical techniques, including cluster analysis (CA), discriminant analysis (DA), principal component analysis (PCA) and factor analysis (FA), were used to evaluate temporal and spatial variations in and to interpret large and complex water quality datasets collected from the Shuangji River Basin. The datasets, which contained 19 parameters, were generated during the 2 year (2018–2020) monitoring programme at 14 different sites (3192 observations) along the river. Hierarchical CA was used to divide the twelve months into three periods and the fourteen sampling sites into three groups. Discriminant analysis identified four parameters (CODMn, Cu, As, Se) loading more than 68% correct assignations in temporal analysis, while seven parameters (COD, TP, CODMn, F, LAS, Cu and Cd) to load 93% correct assignations in spatial analysis. The FA/PCA identified six factors that were responsible for explaining the data structure of 68% of the total variance of the dataset, allowing grouping of selected parameters based on common characteristics and assessing the incidence of overall change in each group. This study proposes the necessity and practicality of multivariate statistical techniques for evaluating and interpreting large and complex data sets, with a view to obtaining better information about water quality and the design of monitoring networks to effectively manage water resources.

The methanogenic degradation of oil hydrocarbons can proceed through syntrophic partnerships of hydrocarbon-degrading bacteria and methanogenic archaea 1 – 3 . However, recent culture-independent studies have suggested that the archaeon ‘ Candidatus Methanoliparum’ alone can combine the degradation of long-chain alkanes with methanogenesis 4 , 5 . Here we cultured Ca . Methanoliparum from a subsurface oil reservoir. Molecular analyses revealed that Ca . Methanoliparum contains and overexpresses genes encoding alkyl-coenzyme M reductases and methyl-coenzyme M reductases, the marker genes for archaeal multicarbon alkane and methane metabolism. Incubation experiments with different substrates and mass spectrometric detection of coenzyme-M-bound intermediates confirm that Ca . Methanoliparum thrives not only on a variety of long-chain alkanes, but also on n -alkylcyclohexanes and n -alkylbenzenes with long n -alkyl (C ≥13 ) moieties. By contrast, short-chain alkanes (such as ethane to octane) or aromatics with short alkyl chains (C ≤12 ) were not consumed. The wide distribution of Ca . Methanoliparum 4 – 6 in oil-rich environments indicates that this alkylotrophic methanogen may have a crucial role in the transformation of hydrocarbons into methane. ‘Candidatus Methanoliparum’ overexpresses genes encoding alkyl-coenzyme M and methyl-coenzyme M reductases—markers of archaeal multicarbon alkane and methane metabolism—and thrives on a variety of long-chain alkanes and n -alkylcyclohexanes, and n -alkylbenzenes with long n -alkyl (C ≥13 ) moieties.

The synthetic organic surfactants linear alkylbenzene sulfonate (LAS) and polycyclic aromatic hydrocarbon naphthalene (NAP), two common organic pollutants, are frequently detected in freshwater environments. However, the combined ecotoxicological risks associated with these pollutants have not been fully elucidated. The present study investigated the effects of individual and combined treatments of LAS and NAP on the growth and physiological responses of Spirodela polyrrhiza . The results showed that LAS was the main compound toxic to S. polyrrhiza in a dose-dependent manner. The peroxidase (POD) enzyme and catalase (CAT) enzyme are the main antioxidant enzymes protecting S. polyrrhiza from LAS stress. When exposed to NAP stress alone, only slightly reversible damage was observed as the exposure time was extended (14 days). The antioxidant enzyme systems (including superoxide dismutase (SOD), CAT and POD) showed positive responses. Synergistic effects were induced with LAS-NAP mixtures (≥ 5 + 5 mg L −1 ), and LAS played a major toxic role. The POD enzyme was a sensitive protective enzyme in duckweed during the joint exposure to LAS + NAP. The results indicate that LAS or NAP may cause serious damage to S. polyrrhiza and aggravate ecotoxicity in aquatic ecosystems .

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 (∆ H 0  =  + 73.89 kJ mol −1 ), entropy driven (∆ S 0  =  + 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.