Oxygenated polycyclic aromatic hydrocarbons (oxyPAHs) are directly discharged into the atmosphere with exhaust gas from diesel engine automobiles and industry and are also generated by photo-oxidation and/or microbial metabolism of parent polycyclic aromatic hydrocarbons (PAHs). They are widely distributed in environment, especially around urban areas. We evaluated the effects of exposure to oxyPAHs as acenaphthenequinone (ANQ), 7,12-benz(a)anthracenequinone (BAQ), 1,4-naphthoquinone (NAQ), and 9,10-phenanethrenequinone (PHQ) in Japanese medaka (Oryzias latipes) embryos. ANQ (>2720 μg/L) caused caving in the yolk sac, and BAQ (>22.4 μg/L) caused tanning of the oil droplet. Additionally, NAQ (>314 μg/L) and PHQ (>734 μg/L) stopped development of medaka embryos beginning 2 days after the start of exposure. The hatched larvae from embryos exposed to ANQ, BAQ, NAQ, or PHQ at 518, 9.86, 36.5, or 80.7 μg/L, respectively, exhibited incomplete development of the cephalic region, incomplete palate, unabsorbed and hypertrophied yolk sac, tubular heart, altered axial curvature, and poor swimming ability. These symptoms were similar to those observed in blue sac disease, which is caused by exposure to PAHs.

Water contaminated with microorganisms causes numerous diseases and is a major concern for public health. In search of a simple material which can provide clean water free from pathogens, nanofibers of poly(4-chloro-3-methylphenyl methacrylate, abbreviated as CMPMA, and nano Ag-doped poly(CMPMA) composite nanofibers were used to decontaminate water from microorganisms such as Escherichia coli and Bacillus subtilis. Nanofibers were prepared by electrospinning. X-ray diffraction (XRD) and transmission electron microscopy (TEM) provide the diameters of the Ag nanoparticles which are in the range 18–21 and 13–18 nm. The diameter of the poly(CMPMA) and nano Ag-doped poly(CMPMA) composite nanofiber is seen to vary between 400 and 700 nm with the change of the processing parameters. Optimum parameters for uniform nanofibers have been obtained. The morphology of the fibers is derived from scanning electron microscopy (SEM). The superiority of the nano Ag-doped poly(CMPMA) composite nanofiber was established.

The HAP crystallization for phosphorus removal from wastewater contributes to an environmental friendly production due to the fact that it helps reduce or eliminate the water eutrophication as well as increases the recovery of mineral resources. However, the generated microcrystalline with poor settleability in high levels of supersaturation solution has a negative effect on the phosphorus recovery efficiency. To overcome the drawback, multiple reagent feed ports (four feed ports) and different recirculation ratio (1.0, 1.5, 2.0, 2.5, 3.0) were investigated to control the levels of supersaturation in an air-agitated reactor with calcite as seeds. Results showed that the approach of multiple reagent feed ports could improve the conversion ratio of orthophosphate, but it had a limited effect (∼3% improvement) on phosphorus recovery efficiency (deposition on the seeds). With the increase of the recirculation ratio, the recovery efficiency was increased gradually and reached an optimal value of 85.63% under the recirculation ratio of 2.5 and four feed ports. This is because the adopted strategies could reduce the level of supersaturation by diluting the concentration of the reagents and inhibit large numbers of microcrystalline coinstantaneous occurrence. Meanwhile, the crystallized products were detected and analyzed by scanning electron micrograph (SEM) with energy-dispersive spectrometry (EDS) and X-ray diffraction (XRD), which were proved to be HAP with a high purity. Collectively, these results demonstrated that supersaturation control using conventional approaches had a limited improvement on the phosphorus recovery efficiency in the form of HAP, and the new control strategies for supersaturation dispersion should be developed in the further study.

Carbon nanoparticles that may be potent air pollutants with adverse effects on human health often contain heteroatoms including sulfur. In order to study in detail their effects on different physiological and biochemical processes, artificially produced carbon dots (CDs) with well-controlled composition that allows fluorescence detection may be of great use. Having been prepared from different types of organic precursors, CDs expose different atoms at their surface suggesting a broad variation of functional groups. Recently, we demonstrated neurotoxic properties of CDs synthesized from the amino acid β-alanine, and it is of importance to analyze whether CDs obtained from different precursors and particularly those exposing sulfur atoms induce similar neurotoxic effects. This study focused on synthesis of CDs from the sulfur-containing precursor thiourea-CDs (TU-CDs) with a size less than 10 nm, their characterization, and neuroactivity assessment. Neuroactive properties of TU-CDs were analyzed based on their effects on the key characteristics of glutamatergic and γ-aminobutyric acid (GABA) neurotransmission in isolated rat brain nerve terminals. It was observed that TU-CDs (0.5–1.0 mg/ml) attenuated the initial velocity of Na⁺-dependent transporter-mediated uptake and accumulation of L-[¹⁴C]glutamate and [³H]GABA by nerve terminals in a dose-dependent manner and increased the ambient level of the neurotransmitters. Starting from the concentration of 0.2 mg/ml, TU-CDs evoked a gradual dose-dependent depolarization of the plasma membrane of nerve terminals measured with the cationic potentiometric dye rhodamine 6G. Within the concentration range of 0.1–0.5 mg/ml, TU-CDs caused an “unphysiological” step-like increase in fluorescence intensity of the рН-sensitive fluorescent dye acridine orange accumulated by synaptic vesicles. Therefore, despite different surface properties and fluorescent features of CDs prepared from different starting materials (thiourea and β-alanine), their principal neurotoxic effects are analogous but displayed at a different level of efficiency. Sulfur-containing TU-CDs exhibit lower effects (by ~30%) on glutamate and GABA transport in the nerve terminals in comparison with sulfur-free β-alanine CDs. Our results suggest considering that an uncontrolled presence of carbon-containing particulate matter in the human environment may pose a toxicity risk for the central nervous system.

This paper reports on a study that investigated the aquatic toxicity of new non-ionic surfactants derived from renewable raw materials, polyoxyethylene glycerol ester (PGE), and their binary mixtures with anionic and non-ionic surfactants. Toxicity of pure PGEs was determined using representative organisms from different trophic levels: luminescent bacteria (Vibrio fischeri), microalgae (Pseudokirchneriella subcapitata), and freshwater crustaceans (Daphnia magna). Relationships between toxicity and the structural parameters such as unit of ethylene oxide (EO) and hydrophilic-lipophilic balance (HLB) were evaluated. Critical micellar concentration (CMC) in the conditions of the toxicity test was also determined. It was found that the toxicity of the aqueous solutions of PGE decreased when the number of EO units in the molecule, HLB, and CMC increased. PGEs showed lower CMC in marine medium, and the toxicity to V. ficheri is lower when the CMC was higher. Given their non-polar nature, narcosis was expected to be the primary mode of toxic action of PGEs. For the mixture of surfactants, we observed that the mixtures with PGE that had the higher numbers of EO units were more toxic than the aqueous solutions of pure surfactants. Moreover, we found that concentration addition was the type of action more likely to occur for mixtures of PGE with lower numbers of EO units with non-ionic surfactants (alkylpolyglucoside and fatty alcohol ethoxylate), whereas for the mixture of PGE with lower EO units and anionic surfactant (ether carboxylic derivative), the most common response type was response addition. In case of mixtures involving amphoteric surfactants and PGEs with the higher numbers of EO units, no clear pattern with regard to the mixture toxicity response type could be observed.

Biosolids contain inorganic and organic contaminants, including pharmaceutical and personal care products (PPCPs) that have accounted for a series of emerging contaminants, such as triclosan (TCS) and the hormone 17α-ethinylestradiol (EE2). The general aim of this study was to evaluate the effects of biosolid application on EE2 and TCS adsorption and bioavailability in soils through testing with wheat plants. For the bioavailability study, sand and two soils, Lampa and Lo Prado, were used. The sand and soils were treated using two biosolid application rates (0 and 90 mg ha⁻¹), and the EE2 and TCS concentrations in the biosolids were determined as 0.54 ± 0.06 and 8.31 ± 0.19 mg kg⁻¹, respectively. The concentration observed in wheat plants indicated that EE2 and TCS are mainly concentrated in the roots rather than in the shoots. Furthermore, the bioavailability of the compounds in plants depends on the properties of the contaminants and the soil. Adsorption studies showed that increasing the soil organic matter content increases the adsorption of TCS and EE2 on these substrates and that both compounds follow the Freundlich adsorption model. The desorption procedure indicated that availability for both TCS and EE2 depended on the soil type because TCS and EE2 were small in the Lampa soil with and without biosolid application and TCS increased by nearly 50% in the Lo Prado soil. The Lo Prado soil had an acidic pH (5.9) and the Lampa soil had a neutral pH of 7.3, and the organic carbon content was smaller.

Some pollutants can be resistant to wastewater treatment, hence becoming a risk to aquatic and terrestrial biota even at the very low concentrations (ng L⁻¹–μg L⁻¹) they are commonly found at. Tertiary treatments are used for micropollutant removal but little is known about the ecotoxicity of the treated effluent. In this study, a municipal secondary effluent was treated by a solar photo-Fenton reactor at initial neutral pH in a raceway pond reactor, and ecotoxicity was evaluated before and after micropollutant removal. Thirty-nine micropollutants were identified in the secondary effluent, mainly pharmaceuticals, with a total concentration of ≈80 μg L⁻¹. After treatment, 99 % microcontaminant degradation was reached. As for ecotoxicity reduction, the assayed organisms showed the following sensitivity levels: Tetrahymena thermophila > Daphnia magna > Lactuca sativa > Spirodela polyrhiza ≈ Vibrio fischeri. The initial effluent showed an inhibitory effect of 40 % for T. thermophila and 20 % for D. magna. After 20 min of photo-Fenton treatment, no toxic effect was observed for T. thermophila and toxicity dropped to 5 % for D. magna. Graphical abstract Ecotoxicity removal by solar photo-Fenton at neutral pH. ᅟ

With the development of ultra-high-voltage direct-current (UHVDC) transmission technology and increase in transmission voltage, the issue of environmental static electric field (SEF) pollution is standing out and its possible health effects have caused much public attention. In this study, the effects of chronic exposure to SEF on reproductive capacity of male mice were investigated. Twenty Institute of Cancer Research (ICR) mice were exposed to SEF (56.3 ± 1.4 kV/m, 49 days) generated by a high-voltage device. Several biological end points related to spermatogenesis and testicular function were evaluated, including reproductive organ coefficients, sperm motility and morphology, serum testosterone level, and testicular histology. No significant differences were found between the SEF-exposed and sham-exposed groups at the end of the exposure period. However, further observation through transmission electron microscopy revealed cristae losses in mitochondria of spermatogenic cells after SEF exposure. Nevertheless, the mitochondria injury did not affect sperm motility, which might be explained from the perspective of energy supply. That is, most of the energy required for sperm movement is generated by glycolysis which occurs in the cytoplasm rather than oxidative phosphorylation which occurs in mitochondria. In conclusion, this study indicates that exposure to SEF (56.3 ± 1.4 kV/m, 49 days) has limited effects on male reproductive capacity.

The oxidation of methane (CH₄) using biofilters has been proposed as an alternative to mitigate anthropogenic greenhouse gas emissions with a low concentration of CH₄ that cannot be used as a source of energy. However, conventional biofilters utilize organic packing materials that have a short lifespan, clogging problems, and are commonly inoculated with non-specific microorganisms leading to unpredictable CH₄ elimination capacities (EC) and removal efficiencies (RE). The main objective of this work was to characterize the oxidation of CH₄ in two biotrickling filters (BTFs) packed with polyethylene rings and inoculated with two methanotrophic bacteria, Methylomicrobium album and Methylocystis sp., in order to determine EC and CO₂ production (pCO₂) when using a specific inoculum. The repeatability of the results in both BTFs was determined when they operated at the same inlet load of CH₄. A dynamic mathematical model that describes the CH₄ abatement in the BTFs was developed and validated using mass transfer and kinetic parameters estimated independently. The results showed that EC and pCO₂ of the BTFs are not identical but very similar for all the conditions tested. The use of specific inoculum has shown a faster startup and higher EC per unit area (0.019 gCH₄ m⁻² h⁻¹) in comparison to most of the previous studies at the same CH₄ load rate (23.2 gCH₄ m⁻³ h⁻¹). Global mass balance showed that the maximum reduction of CO₂ equivalents was 98.5 gCO₂ₑq m⁻³ h⁻¹. The developed model satisfactorily described CH₄ abatement in BTFs for a wide range of conditions.

Perfluoroalkyl substances (PFASs) are a class of widely used chemicals that have been detected in the environment and general population. However, the isomer patterns in human are poorly characterized. Previous studies observed the isomer-specific maternal-fetal transfer of PFASs in human. In our current study, we first examined the profile of PFASs and isomers, including 17 linear PFASs and 10 branched PFOS/PFOA isomers by using isotopic internal standards in umbilical cord serum samples from Guangzhou, China. We collected a total of 321 of cord blood serum samples from July to October in 2013, and analyzed the PFASs concentration with isomer-specific PFASs analysis method. The results showed that 9 out of 17 PFASs (linear PFASs) were detected (>50% detection rate). Perfluorohexane sulfonate (PFHxS, median 3.87 ng/mL) was the predominant, followed by total PFOS (median 2.99 ng/mL) and total PFOA (median 1.23 ng/mL) in cord serum. In addition, 1m-, iso-, ∑3+4+5m-PFOS and iso-PFOA were the branched PFASs detected in the current study. The proportion of linear PFOS (n-PFOS) was 75.16% of ∑PFOS which was similar to the proportion of electrochemical fluorination that produces ca. 70% linear PFOS and 30% branched. On the contrary, linear PFOA (n-PFOA) accounted for 98.69% ∑PFOA in cord serum samples. Our finding indicates distinct PFASs and PFOS/PFOA isomer profile in cord serum, suggesting there might be a different exposure pathway and metabolism of PFASs.