Effective degradation of benzene was achieved in sodium percarbonate (SPC)/Fe(II)-Glu system. The presence of glutamate (Glu) could enhance the regeneration of Fe(III) to Fe(II), which ensures the benzene degradation efficiency at wider pH range and eliminate the influence of HCO₃⁻ in low concentration. Meanwhile, the significant scavenging effects of high HCO₃⁻ concentration could also be overcome by increasing the Glu/SPC/Fe(II)/benzene molar ratio. Free radical probe compound tests, free radical scavenger tests, and electron paramagnetic resonance (EPR) analysis were conducted to explore the reaction mechanism for benzene degradation, in which hydroxyl radical (HO•) and superoxide anion radical (O₂•⁻) were confirmed as the predominant species responsible for benzene degradation. In addition, the results obtained in actual groundwater test strongly indicated that SPC/Fe(II)-Glu system is applicable for the remediation of benzene-contaminated groundwater in practice.

On the basis of a previous study performed in our laboratory, the use of organic and inorganic amendments can significantly modify the Hg mobility in soil. We have compared the effectiveness of organic and inorganic amendments such as digestate and fly ash, respectively, reducing the Hg mobility in Chernozem and Luvisol soils differing in their physicochemical properties. Hence, the aim of this work was to compare the impact of digestate and fly ash application on the chemical and biochemical parameters in these two mercury-contaminated soils in a model batch experiment. Chernozem and Luvisol soils were artificially contaminated with Hg and then incubated under controlled conditions for 21 days. Digestate and fly ash were applied to both soils in a dose of 10 and 1.5 %, respectively, and soil samples were collected after 1, 7, 14, and 21 days of incubation. The presence of Hg in both soils negatively affected to processes such as nitrification, provoked a decline in the soil microbial biomass C (soil microbial biomass C (MBC)), and the microbial activities (arylsulfatase, and β-glucosaminidase) in both soils. Meanwhile, the digestate addition to Chernozem and Luvisol soils contaminated with Hg improved the soil chemical properties (pH, dissolved organic carbon (DOC), N (Nₜₒₜ), inorganic–N forms (N–NH₄ ⁺ and N–NO₃ ⁻)), as consequence of high content in C and N contained in digestate. Likewise, the soil MBC and soil microbial activities (dehydrogenase, arylsulfatase, and β-glucosaminidase) were greatly enhanced by the digestate application in both soils. In contrast, fly ash application did not have a remarkable positive effect when compared to digestate in Chernozem and Luvisol soil contaminated with mercury. These results may indicate that the use of organic amendments such as digestate considerably improved the soil health in Chernozem and Luvisol compared with fly ash, alleviating the detrimental impact of Hg. Probably, the chemical properties present in digestate may determine its use as a suitable amendment for the assisted-natural attenuation of mercury-polluted soils.

About a quarter of the human diseases occurs for exposure to air pollution. The male reproductive system, and especially spermatogenesis, seems to be particularly sensitive. As result, male infertility is increasing in industrial countries becoming a top priority for public health. In addition to psychological distress and economic constraints, poorer semen quality may have trans-generational effects including congenital malformations in the offspring and predispose to later onset adult diseases. Genetic and epigenetic alterations are involved in the failure of spermatogenesis. In this paper, we reviewed the major evidences of the effects of air pollutants on male infertility as well as the role of sperm DNA damage and epigenetic changes in affecting spermatogenesis. A better knowledge on the effects of air contaminants on the molecular mechanisms leading to infertility is of huge importance to help clinicians in identifying the cause of infertility but above all, in defining preventive and therapeutic protocols.

Lichens are known to synthesize a variety of secondary metabolites having multifunctional activity in response to external environmental condition. Two common lichen extrolites, atranorin and salazinic acid, are known to afford antioxidant as well as photoprotectant nature depending on the abiotic/biotic stress. The present investigation aims to study the influence of altitudinal gradient on the quantitative profile of atranorin and salazinic acid in three lichen species, Bulbothrix setschwanensis (Zahlbr.) Hale, Everniastrum cirrhatum (Fr.) Hale and Parmotrema reticulatum (Taylor) Choisy, Parmeliaceae using liquid chromatography-mass spectrometry (LC-MS/MS) technique. Samples were collected from high-altitude area, usually considered as non-polluted sites of Garhwal Himalaya. Characterization and quantification of the lichen substances in samples were carried out comparing with the standards of atranorin and salazinic acid. Results indicated significant variation in the chemical content with the rising altitude. All the three lichen species showed higher quantities of chemical substances with the altitudinal rise, while among the three lichen species, E. cirrhatum showed the highest quantity of total lichen compounds. The higher abundance and frequency of E. cirrhatum with increasing altitude as compared to B. setschwanensis and P. reticulatum may be attributed due to the presence of higher quantity of photoprotecting/antioxidant chemicals especially salazinic acid. Thus, the present study shows the prominent role of secondary metabolite in wider ecological distribution of Parmelioid lichens at higher altitudes.

Total selenium removal by the activated sludge process, where selenite is reduced to colloidal elemental selenium nanoparticles (BioSeNPs) that remain entrapped in the activated sludge flocs, was studied. Total selenium removal efficiencies with glucose as electron donor (2.0 g chemical oxygen demand (COD) L⁻¹) at neutral pH and 30 °C gave 2.9 and 6.8 times higher removal efficiencies as compared to the electron donors lactate and acetate, respectively. Total selenium removal efficiencies of 79 (±3) and 86 (±1) % were achieved in shake flasks and fed batch reactors, respectively, at dissolved oxygen (DO) concentrations above 4.0 mg L⁻¹ and 30 °C when fed with 172 mg L⁻¹ (1 mM) Na₂SeO₃ and 2.0 g L⁻¹ COD of glucose. Continuously operated reactors operating at neutral pH, 30 °C and a DO >3 mg L⁻¹ removed 33.98 and 36.65 mg of total selenium per gram of total suspended solids (TSS) at TSS concentrations of 1.3 and 3.0 g L⁻¹, respectively. However, selenite toxicity to the activated sludge led to failure of a continuously operating activated sludge reactor at the applied loading rates. This suggests that a higher hydraulic retention time (HRT) or different reactor configurations need to be applied for selenium-removing activated sludge processes.

The acute toxicity of titanium dioxide nanoparticles (nTiO₂) that occur concomitantly in the aquatic environment with other contaminants such as arsenic (As) is little known in crustaceans. The objective of the present study is to evaluate whether coexposure to nTiO₂ can influence the accumulation, metabolism, and oxidative stress parameters induced by arsenic exposure in the gills and hepatopancreas of the shrimp Litopenaeus vannamei. Organisms were exposed by dissolving chemicals in seawater (salinity = 30) at nominal concentrations of 10 μg/L nTiO₂ or Asᴵᴵᴵ, dosed alone and in combination. Results showed that there was not a significant accumulation of As in either tissue type, but the coexposure altered the pattern of the metabolism. In the hepatopancreas, no changes were observed in the biochemical response, while in the gills, an increase in the glutamate-cysteine-ligase (GCL) activity was observed upon exposure to As or nTiO₂ alone, an increase in the reduced glutathione (GSH) levels was observed upon exposure to As alone, and an increase in the total antioxidant capacity was observed upon exposure to nTiO₂ or nTiO₂ + As. However, these modulations were not sufficient enough to prevent the lipid damage induced by nTiO₂ exposure. Our results suggest that coexposure to nTiO₂ and As does not alter the toxicity of this metalloid in the gills and hepatopancreas of L. vannamei but does alter its metabolism, favoring its accumulation of organic As species considered moderately toxic.

The interaction between a river and the sea results in a turbidity maximum zone (TMZ) within the estuary, which has a great impact on the local ecosystem. In the Yangtze River Estuary, the magnitude and extent of the TMZ vary with water discharge. In this study, the cumulative human activity altered the water discharge regime from the river to the estuary. In the post-Three Gorges Dam (TGD) period, water discharge increased by 35.10 % at Datong in February compared with that in the pre-TGD period. The effects of water discharge variation on the characteristics of the TMZ were analyzed during spring and neap tidal periods using the three-dimensional environmental fluid dynamic code (EFDC) model. The area of the TMZ decreased by 3.11 and 17.39 % during neap and spring tides, respectively. In addition, the upper limit of the TMZ moved 11.68 km seaward during neap tide, whereas the upper limit of the TMZ in the upstream and downstream areas moved seaward 9.65 and 2.34 km, respectively, during spring tide. These findings suggest that the area and location of the TMZ are more sensitive to upstream runoff during spring tide than during neap tide. These changes in the TMZ will impact the biochemical processes in the Yangtze River Estuary. In the foreseeable future, the distribution characteristic of TMZ will inevitably change due to variations in the Yangtze River discharge resulting from new human activities (i.e., new dams), which are being constructed upstream in the Yangtze River system.

Atrazine is an herbicide widely used in crops and has drawn attention due to potential pollution present in soil, sediment, water, and food. Since conventional methods are not potentially efficient to persistent degradation of organic compounds, new technology has been developed to remove them, especially practices utilizing advanced oxidation processes (AOPs). This work aims to evaluate the use of different energies (ultraviolet (UV), microwaves (MW), and radiations (MW-UV)) to the herbicide atrazine through the process of photo-oxidation. These systems found degradation rates of around 12 % (UV), 28 % (MW), and 83 % (MW-UV), respectively, with time intervals of 120 s. After the photolytic processes, the samples were analyzed at a wavelength scanning the range of 190 to 300 nm, where the spectral analysis of the signal was used to evaluate the degradation of atrazine and the appearance of some other peaks (degradation products). The spectrum evaluation resulting from photolytic processes gave rise to a new signal which was confirmed by chromatography. This spectrum indicated the possible pathway of atrazine degradation by the process of photolytic MW-UV, generating atrazine-2-hydroxy, atrazine-desethyl-2-hidroxy, and atrazine-desisopropyl-2-hydroxy. The process indicated that in all situations, chloride was present in the analytic structure and was substituted by a hydroxyl group, which lowered the toxicity of the compound through the photolytic process MW-UV. Chromatographic analysis ascertained these preliminary assessments using spectrophotometry. It was also significantly observed that the process can be optimized by adjusting the pH of the solution, which was evident by an improvement of 10 % in the rate of degradation when subjected to a pH solution equal to 8.37.

Phosphorus (P) is an essential nutrient for aquatic organisms. However, too much P discharged into limnetic ecosystems can induce eutrophication. The concentration of P in freshwater ecosystems has escalated in Eastern China due to overuse of fertilizer and excess emission of sewage, which is the result of the development of industry and agriculture in this area. However, little is known about the P characteristics and its environmental factors in river systems. Here, we present the results of P characterization and its relationships with environmental factors in Eastern China by applying SMT and ³¹P-NMR methods. The results showed that the concentrations of P in surface sediments varied with the river system, and more than 50 % of the samples had P concentrations exceeding 500 mg kg⁻¹. HCl-Pi was the dominant Pi in surface sediments, with the highest percentage (96.5 %) in the Yellow River System. Mono-P was the dominant Po in river sediments, followed by DNA-P. The PCA approach indicated that NaOH-Pi and ortho-P clustered in one group, with a second group including mono-P, diesters-P, and HCl-Pi. Phon-P and pyro-P belonged to different groups. On a regional scale, NaOH-Pi and Po showed a negative relationship with pH in sediments. Continuous eutrophication was induced by the presence of dams, and oxygen-consuming pollutants, such as NH₃-N and CODcr, even when external P input was cut in heavily polluted rivers. The research revealed the characteristics of P in different river systems and proposed a conceptual model of P biogeochemical cycles in heavily polluted rivers. Results from this study may provide insight into P characteristics in Eastern China and would set a scientific basis for effective P management in developing countries.

Pollution of agricultural soils caused by widely employed plastic products, such as phthalic acid esters (PAEs), are becoming widespread in China, and they have become a threat to human health and the environment. However, little information is available on the influence of PAEs on vegetable crops. In this study, effects of different dimethyl phthalate (DMP) treatments (0, 30, 50, 100, and 200 mg L⁻¹) on seed germination and growth of cucumber seedlings were investigated. Although germination rate showed no significant difference compared to control, seed germination time was significantly delayed at DMP greater than 50 mg L⁻¹. Concentrations of DMP greater than 30 mg L⁻¹ reduced cucumber lateral root length and number. The measurement of five physiological indexes in cucumber leaves with increasing DMP concentration revealed a decrease in leaf chlorophyll content, while proline and H₂O₂ contents increased. Peroxidase (POD) and catalase (CAT) activities increased in cucumber plants under 30 and 50 mg L⁻¹ DMP treatments compared to control; while after a 7-day treatment, these activities were seriously reduced under 100 and 200 mg L⁻¹ DMP treatments. According to transmission electron microscopy (TEM) micrographic images, the control and 30 mg L⁻¹ DMP treatments caused no change to leaf chloroplast shape with well-structured thylakoid membrane and parallel pattern of lamellae. At concentrations higher than 30 mg L⁻¹, DMP altered the ultrastructure of chloroplast, damaged membrane structure, disordered the lamellae, and increased the number and volume of starch grains. Moreover, the envelope of starch grains began to degrade under 200 mg L⁻¹ DMP treatment.