To better understand the characterization and secondary organic aerosol (SOA) formation of volatile organic compounds (VOCs) during non-haze and haze days, ambient VOCs were continuously measured by a vehicle-mounted online thermal desorption system coupled with a gas chromatography–mass spectrometry (TD–GC/MS) system in Shanghai, China. The average concentrations of VOCs in haze episodes (193.2 μg m⁻³) were almost 50% higher than in non-haze periods (130.8 μg m⁻³). VOC concentrations exhibited a bi-modal pattern in the morning and evening rush hour periods on both non-haze and haze days. The ratios of toluene to benzene (T/B) and m,p-xylene to ethylbenzene (X/E) indicated that VOCs were aged air mass transported from nearby areas. The estimated SOA yields were 12.6 ± 5.3 and 16.7 ± 6.7 μg m⁻³ for non-haze and haze days, respectively, accounting for 9.6 and 8.7% of the corresponding PM₂.₅ concentrations, which were slightly underestimated. VOCs–sensitivity (VOCs–S) based on a PM₂.₅-dependent model was used to investigate the variation between VOCs and PM₂.₅ concentrations in the morning rush hour. It was found that VOCs were more sensitive to PM₂.₅ on clean days than during periods of heavy particulate pollution. VOCs–sensitivity was significantly correlated with the ratio of specific PM₂.₅ to background PM₂.₅, with a simulated equation of y = 0.84x⁻⁰.⁶² (r ² = 0.93, p < 0.001). Our findings suggest that strategies to mitigate VOC emissions and further alleviate haze episodes in Shanghai based on reducing gasoline vehicle-related sources would be very efficient.

A total of 54 raw wastewater samples collected from three urban treatment plants and two slaughterhouses in Tehran, Iran, were assessed for the presence of the Giardia cysts using immunofluorescence with monoclonal antibodies. To characterize the cysts at the molecular level, the three genetic loci were amplified and sequenced. The assemblages A (37.5 %) and E (58.3 %) were detected in livestock wastewater samples. Assemblage A, which is composed of only G. duodenalis genotype, was detected in 100 % of urban wastewater samples. The subassemblages A2, A3, A-I, A-II, and E3 were identified with β-giardin, triose phosphate isomerase, and glutamate dehydrogenase genes. This study is the first to report on G. duodenalis genotypes in aquatic environmental samples in Iran.

Single extraction methods have been extensively used to assess the availability of metals in polluted soils. This work focused on checking the feasibility of several chemicals, i.e. CaCl₂, EDTA, diethylenetriaminepentaacetic acid (DTPA) and a low-molecular-weight organic acid mixture (rhizosphere-based method), to be used as extractants for mercury (Hg) in a soil from the Almadén mining district (Spain). Moreover, the effect of several experimental parameters, i.e. extraction time (0.5, 1, 2, 5, 16 and 24 h), concentration of extractant (0.01, 0.05, 0.1 and 1 M) and soil/extractant ratio (1:2, 1:5 and 1:10), on the amount of Hg extracted was investigated. The Hg extraction ability followed the descending order EDTA > rhizosphere-based method > DTPA ≈ CaCl₂. This ranking was attributed to the higher complexation power of EDTA and organic acids. It was also found that extraction times between 2 and 5 h are required to avoid underestimation of mobile Hg and re-adsorption of the Hg previously extracted. Although some exceptions were found, Hg extraction efficiency was generally enhanced with higher extractant concentrations. Finally, the amount of Hg extracted by the four extractants increased with decreasing soil/extractant ratios.

Textile manufacturing is the one responsible for water bodies’ contamination through the discharge of colored wastes. This work presents the study of reactive yellow HF (RYHF) dye degradation under two different electrochemical advanced oxidation processes (EAOP), namely anodic oxidation (AO) and electro-Fenton (EF)/boron-doped diamond (BDD) process. For the AO, 100 and 300 mg/L solutions using Pt and BDD as anodes in a 100 mL stirred tank cell were used, with a supporting electrolyte of 0.05 mol/L of Na₂SO₄ at pH 3 under 30 and 50 mA/cm² current density. The EF/BDD process was carried out in a flow reactor at 4 and 7 L/min to degrade 100, 200, and 300 mg/L RYHF solutions under 50 and 80 mA/cm². UV-Vis determinations were used for decolorization evaluation, while high-performance liquid chromatography (HPLC) method provided information on dye degradation rate.

Triclocarban (TCC) is an antibacterial agent found in pharmaceuticals and personal care products (PPCP). It is potentially bioaccumulative and an endocrine disruptor, being classified as a contaminant of emerging concern (CEC). In normal uses, approximately 96% of the used TCC can be washed down the drain going into the sewer system and eventually enter in the aquatic environment. UV photolysis can be used to photodegrade TCC and ecotoxicity assays could indicate the photodegradation efficiency, since the enormous structural diversity of photoproducts and their low concentrations do not always allow to identify and quantify them. In this work, the TCC was efficiently degraded by UVC direct photolysis and the ecotoxicity of the UV-treated mixtures was investigated. Bioassays indicates that Daphnia similis (48 h EC₅₀ = 0.044 μM) was more sensitive to TCC than Pseudokirchneriella subcapitata (72 h IC₅₀ = 1.01 μM). TCC and its photoproducts caused significant effects on Eisenia andrei biochemical responses (catalase and glutathione-S-transferase); 48 h was a critical exposure time, since GST reached the highest activity values. UVC reduced the TCC toxic effect after 120 min. Furthermore, TCC was photodegraded in domestic wastewater which was simultaneously disinfected for total coliform bacterial (TCB) (360 min) and Escherichia coli (60 min). Graphical abstract TCC degradation and ecotoxicological assessment

To understand the relationship between chemical and microbial treatment at each treatment step, as well as the relationship between microbial community structure in biofilms in biofilters and their ecological functions, a drinking water plant with severe organic matter-polluted source water was investigated. The bacterial community dynamics of two drinking water supply systems (traditional and advanced treatment processes) in this plant were studied from the source to the product water. Analysis by 454 pyrosequencing was conducted to characterize the bacterial diversity in each step of the treatment processes. The bacterial communities in these two treatment processes were highly diverse. Proteobacteria, which mainly consisted of beta-proteobacteria, was the dominant phylum. The two treatment processes used in the plant could effectively remove organic pollutants and microbial polution, especially the advanced treatment process. Significant differences in the detection of the major groups were observed in the product water samples in the treatment processes. The treatment processes, particularly the biological pretreatment and O₃–biological activated carbon in the advanced treatment process, highly influenced the microbial community composition and the water quality. Some opportunistic pathogens were found in the water. Nitrogen-relative microorganisms found in the biofilm of filters may perform an important function on the microbial community composition and water quality improvement.

The present study investigated the effect of copper on photosynthesis, antioxidant potential, and anatomical response of aquatic fern, Salvinia cucullata, with a view to ascertain its phytoremediation potential. Plants were exposed in hydroponics for 21 days to different Cu concentrations (10, 15, 20, and 30 mg/L). Significant declines in chlorophyll, carotenoids, and soluble proteins, as a function of Cu proportion were observed. Lipid peroxidation was also evident, which implied reactive oxygen species (ROS) generation. However, both root and leaf tissues responded remarkably to the ROS produced, by inducing superoxide dismutase (1.6–6.5 times), catalase (1.5–5.4 times), guaicol peroxidase (1.5–7.2 times), and ascorbyl peroxidase (1.3–4.7 times) over the control. The plant showed best phytoremedial activity within Cu range of 10–15 mg/L, with maximum accumulation of 2956 ± 82.6 μg/g dw., at 15 mg Cu/L and showed efficient root to shoot translocation (translocation factor, TF > 1) at this range, which is the stipulated minimum requirement to be a hyperaccumulator. The capacity of metal extraction from environment to leaf (extraction coefficient, EC) was also high (EC = 73–197). However, at higher doses (20–30 mg/L), the plant resorted to an exclusion strategy, whereby, more metal accumulation was observed in root than in leaf. The plant conferred suitable remediation attributes by showing minimal root and leaf anatomical damages along with high Ca peaks in both the tissues, and rapid leaf stomatal closure, all of which probably helped in the Cu induced stress mitigation. Due to its widespread availability, fast growth, ability to grow in myriads of polluted environment, and having hardy physiology, this plant can be suggested for use as a suitable Cu phytoremediator.

Magnetic cerium-doped mesoporous titanium dioxide was synthesized by combining sol–gel method and calcination using tetrabutanate and ammonium cerium nitrate as precursors and Pluronic P123 as a template coating on iron oxide covered with carbon in ethanol. The magnetic Ce-doped catalyst showed only anatase structure with a slight increase in lattice parameters compared to the undoped catalyst. The Ce LIII-edge X-ray absorption near-edge spectroscopy (XANES) spectra showed Ce³⁺, and the cerium substitution doping into titanium dioxide was proposed. Degradation of S-metolachlor in aqueous magnetic photocatalyst suspension followed (pseudo) first-order kinetics in the presence of 0.5 g L⁻¹ of γ-Fe₂O₃@[email protected] mol% Ce-mTiO₂ with a half-life of 55.18 ± 1.63 min. Fifteen degradation products were identified, and their transformation routes of the photocatalytic degradation were then proposed. Complementary toxicity assessment of the treated S-metolachlor solution was undertaken with Environment Canada’s algal microplate assay measuring growth inhibition (72-h IC₅₀) in the freshwater chlorophyte Pseudokirchneriella subcapitata. This test method revealed a significant decrease in toxicity (1.7-fold reduction after 180 min of irradiation treatment), thereby confirming that the by-products formed following photocatalysis would be less harmful from an environmental point of view. Photocatalytic degradation of S-metolachlor thus appears to hold promise as a cost-effective treatment technology to diminish the presence of this herbicide in aquatic systems.

In this work, the main objectives were to assess the mutagenic and genotoxic effects of fine particulate matter collected in an industrial influenced site in comparison with a non-industrial influenced one (rural site) and to relate the particulate matter (PM) composition to the observed genotoxic effects. At the industrial influenced site, higher concentrations of phosphates, trace metals, and polycyclic aromatic hydrocarbons (PAHs) in particles could be related to the contributions of quarries, fertilizer producer, cement plants, and tires burning. Gasoline and diesel combustion contributions were evidenced in particles collected at both sites. Particles collected under industrial influence showed a higher mutagenic potential on three tested strains of Salmonella typhimurium (TA98, YG1041, and TA102), and especially on the YG1041, compared to particles from the rural site. Furthermore, only particles collected in the vicinity of the industrial site showed a tendency to activate the SOS responses in Escherichia coli PQ37, which is indicative of DNA damage as a result of exposure of the bacteria cells to the action of mutagenic samples. The mutagenicity and genotoxicity of the industrial PM₂.₅–₀.₃ particulates may be attributed to its composition especially in organic compounds. This study showed that proximity of industries can affect local PM composition as well as PM genotoxic and mutagenic potential.

Nitrite is present as a noxious contaminant in drinking water and causes oxidative damage in various tissues of humans and animals. It is a well-known methemoglobin-forming agent that has been shown to damage blood cells. The protective effect of taurine, a semi-essential sulfur-containing amino acid, was studied on sodium nitrite (NaNO₂)-induced oxidative damage in human erythrocytes. Erythrocytes were incubated with NaNO₂, in the presence and absence of taurine, and changes in oxidative stress parameters determined. Pretreatment with taurine significantly ameliorated NaNO₂-induced oxidative damage to lipids, proteins, and plasma membrane. It also reduced the NaNO₂-induced increase in methemoglobin levels and ROS production. Taurine improved the antioxidant capacity of cells, restored the alterations in the activities of various metabolic enzymes, and prevented morphological changes in erythrocytes. Thus, taurine can be potentially used as a protective agent against the damaging effects of nitrite.