Chrysotile is the most widely used form of asbestos worldwide. China is the world’s largest consumer and second largest producer of chrysotile. The carcinogenicity of chrysotile has been extensively documented, and accumulative evidence has shown that chrysotile is capable of causing lung cancer and other forms of cancer. However, molecular mechanisms underlying the tumorigenic effects of chrysotile remained poorly understood. To explore the carcinogenicity of chrysotile, Wistar rats were administered by intratracheal instillation (by an artificial route of administration) for 0, 0.5, 2, or 8 mg/ml of natural chrysotile (from Mangnai, Qinghai, China) dissolved in saline, repeated once a month for 6 months (a repeated high-dose exposure which may have little bearing on the effects following human exposure). The lung tissues were analyzed for viscera coefficients and histopathological alterations. Expression of P53, P16, C-JUN, and C-FOS was measured by western blotting and qRT-PCR. Our results found that chrysotile exposure leads the body weight to grow slowly and lung viscera coefficients to increase in a dose-dependent manner. General sample showed white nodules, punctiform asbestos spots, and irregular atrophy; moreover, HE staining revealed inflammatory infiltration, damage of alveolar structures, agglomerations, and pulmonary fibrosis. In addition, chrysotile can induce inactivation of the anti-oncogene P53 and P16 and activation of the proto-oncogenes C-JUN and C-FOS both in the messenger RNA and protein level. In conclusion, chrysotile induced an imbalanced expression of cancer-related genes in rats’ lung tissue. These results contribute to our understanding of the carcinogenic mechanism of chrysotile.

Anthropogenic CO₂ emissions from cities represent a major source contributing to the global atmospheric CO₂ burden. Here, we examined the enhancement of atmospheric CO₂ mixing ratios by anthropogenic emissions within the Yangtze River Delta (YRD), China, one of the world’s most densely populated regions (population greater than 150 million). Tower measurements of CO₂ mixing ratios were conducted from March 2013 to August 2015 and were combined with numerical source footprint modeling to help constrain the anthropogenic CO₂ emissions. We simulated the CO₂ enhancements (i.e., fluctuations superimposed on background values) for winter season (December, January, and February). Overall, we observed mean diurnal variation of CO₂ enhancement of 23.5~49.7 μmol mol⁻¹, 21.4~52.4 μmol mol⁻¹, 28.1~55.4 μmol mol⁻¹, and 29.5~42.4 μmol mol⁻¹ in spring, summer, autumn, and winter, respectively. These enhancements were much larger than previously reported values for other countries. The diurnal CO₂ enhancements reported here showed strong similarity for all 3 years of the study. Results from source footprint modeling indicated that our tower observations adequately represent emissions from the broader YRD area. Here, the east of Anhui and the west of Jiangsu province contributed significantly more to the anthropogenic CO₂ enhancement compared to the other sectors of YRD. The average anthropogenic CO₂ emission in 2014 was 0.162 (± 0.005) mg m⁻² s⁻¹ and was 7 ± 3% higher than 2010 for the YRD. Overall, our emission estimates were significantly smaller (9.5%) than those estimated (0.179 mg m⁻² s⁻¹) from the EDGAR emission database.

The aim of this study was to analyze the mechanisms, stoichiometry, and stability of 4-chlorophenol (4CP) biodegradation kinetics by phenol-acclimated activated sludge using open respirometry. While the removal of 4CP was higher than 98%, the removal of chemical oxygen demand (COD) ranged between 69 and 79% due to the accumulation of an intermediate metabolite. The value obtained from respirometric profiles for the stoichiometric ratio of O₂ to 4CP (YO₂/₄CP) was 1.95 ± 0.04 mol of oxygen consumed per mol of 4CP removed. This YO₂/₄CP value reflected the action of the oxygenases responsible for the first steps of the aerobic oxidation of 4CP. The 4CP degradation activity decreased noticeably when successive pulses of 4CP were added to the respirometer. A mathematical model was developed to represent the aerobic biodegradation of 4CP. The fitted model adequately predicted the oxygen consumption rate, total phenols, and soluble COD concentrations as a function of time. The results presented could help to predict the dynamic of biodegradation of chlorophenols in a biological wastewater treatment system.

The production of biofuels from microalgae is a promising and sustainable alternative. Its production is determined by the content of lipids and carbohydrates, which is different for each microalgae species and is affected by environmental factors, being lighting one of the principal determining their biochemical composition. The colour temperature (electromagnetic radiation and light spectrum) is a determining factor for the production of lipids and carbohydrates in microalgae. The aim of this assay was to evaluate the effect of three colour temperatures (6500, 10,000 and 20,000 °K) on the biomass (cel mL⁻¹), biomass production and productivity (g L⁻¹ and g L⁻¹ day⁻¹), lipid and carbohydrate content (%), lipid and carbohydrate production and productivity (mg L⁻¹ and mg L⁻¹ day⁻¹), composition and content of fatty acids (%) in two microalgae species: Dunaliella salina and Nannochloropsis oculata. The highest cell density was observed for N. oculata in stationary phase in the control (83.93 × 106 cel mL⁻¹). However, higher lipid content was obtained in D. salina in stationary phase at 10,000 °K (80%), while N. oculata showed 67% at 6500 °K. The highest carbohydrate content was 25% in stationary phase for D. salina at 20,000 °K. Regarding the production of lipids, D. salina reached a maximum of 523 mg L⁻¹ in exponential phase at 6500 and 10,000 °K. The highest carbohydrate production was 38 mg L⁻¹ for D. salina in exponential phase at 20,000 °K. In both microalgae, 15 different fatty acids were identified; the most abundant was palmitic acid with 35.8% for N. oculata in stationary phase at 10,000 °K, while D. salina showed 67% of polyunsaturated fatty acids in exponential phase at 6500 °K. In conclusion, the ideal colour temperature for microalgae culture to obtain biofuels should be based on the biomolecule of interest, being necessary to individually evaluate for each species.

Granulation of biomass is at the basis of the operation of the most successful anaerobic systems (UASB, EGSB and IC reactors) applied worldwide for wastewater treatment. Despite of decades of studies of the biomass granulation process, it is still not fully understood and controlled. “Degranulation/lack of granulation” is a problem that occurs sometimes in anaerobic systems resulting often in heavy loss of biomass and poor treatment efficiencies or even complete reactor failure. Such a problem occurred in Mexico in two full-scale UASB reactors treating cheese wastewater. A close follow-up of the plant was performed to try to identify the factors responsible for the phenomenon. Basically, the list of possible causes to a granulation problem that were investigated can be classified amongst nutritional, i.e. related to wastewater composition (e.g. deficiency or excess of macronutrients or micronutrients, too high COD proportion due to proteins or volatile fatty acids, high ammonium, sulphate or fat concentrations), operational (excessive loading rate, sub- or over-optimal water upflow velocity) and structural (poor hydraulic design of the plant). Despite of an intensive search, the causes of the granulation problems could not be identified. The present case remains however an example of the strategy that must be followed to identify these causes and could be used as a guide for plant operators or consultants who are confronted with a similar situation independently of the type of wastewater. According to a large literature based on successful experiments at lab scale, an attempt to artificially granulate the industrial reactor biomass through the dosage of a cationic polymer was also tested but equally failed. Instead of promoting granulation, the dosage caused a heavy sludge flotation. This shows that the scaling of such a procedure from lab to real scale cannot be advised right away unless its operability at such a scale can be demonstrated.

This paper evaluates the cesium adsorption of marine actinobacterium Nocardiposis sp. 13H strain isolated from nuclear power plant sites in India. It could remove 88.6 ± 0.72% of Cs⁺ from test solution containing 10 mM CsCl₂. The biosorption of Cs⁺ with different environmental factors such as pH, temperature, and time interval is also determined. Scanning electron microscopy coupled with energy dispersive spectroscopy (EDS) confirmed the Cs⁺ adsorption by Nocardiopsis sp. 13H. Most of the bound cesium was found to be associated extracellular polymeric substances (EPS) suggesting its interaction with the surface active groups. The main component of the EPS was carbohydrate followed by protein and nucleic acid. Further, Fourier transform infrared (FTIR) spectroscopy suggested the carboxyl, hydroxyl, and amide groups on the strain cell surface were likely to be involved in Cs⁺ adsorption. Results from this study show Nocardiopsis sp. 13H microorganism could be useful in exploring the biosorption of radioisotope pollution and developing efficient and eco-friendly biosorbent for environmental cleanup.

Oil spills in the marine environment can cause ecosystem-level impacts. Dispersant application as an oil spill response measure leads to the widespread distribution of hydrocarbons in the water column and marine sediments. The North Sea is an area of intense hydrocarbon production and is at risk of oil spills, which are of concern to its benthic ecosystem due to its sediments’ high permeability. Here, entrainment of hydrocarbons via pore-water advection into permeable North Sea sands and the associated effect of Superdispersant-25, a commercial oil dispersant, were evaluated in a laboratory. Centrally stirred chambers that induce advective pore-water fluxes in sediments were filled with sediment, seawater and mixtures of oil and Superdispersant-25. Dispersant application had contrasting effects on hydrocarbon interactions with sediment: (1) it reduced accumulation of hydrocarbons in surface sediments and (2) facilitated the entrainment of hydrocarbons up to 8 cm deep into sediments by increasing hydrocarbon solubility in seawater and its subsequent washout or pumping into sediment by pore-water movement. Results here show that dispersant application can have counter-intuitive effects on hydrocarbon interactions with marine sediments and highlight the need for further research in this area to make better informed decision in an oil spill response scenario.

Wastewater streams containing hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) are subject to regulatory discharge regulations that require processing through industrial waste treatment. Thus, the development of easy-to-apply technologies for the treatment of RDX-laden wastewater streams is imperative. In the present study, the reduction of RDX by granular zero valent iron (GZVI) in batch and column experiments was investigated. Preliminary batch tests conducted under both oxic and anoxic conditions showed that after 3.0 h of reaction with GZVI, RDX was mainly converted to formaldehyde (CH₂O), nitrate (NO₃⁻), and ammonium (NH₄⁺). Column filtration tests showed that pretreatment of the GZVI media with acid wash and low influent pH (4.0 ± 0.1) achieved 99% removal of RDX up to 5000 bed volume. BOD tests carried out on the post-treatment streams showed increased biodegradability of the treated wastewater, leading to a lower environmental impact for the final waste.

Anopheles stephensi acts as vector of Plasmodium parasites, which are responsible for malaria in tropical and subtropical areas worldwide. Currently, malaria management is a big challenge due to the presence of insecticide-resistant strains as well as to the development of Plasmodium species highly resistant to major antimalarial drugs. Therefore, the present study focused on biosurfactant produced by two bacteria Bacillus subtilis A1 and Pseudomonas stutzeri NA3, evaluating them for insecticidal applications against malaria mosquitoes. The produced biosurfactants were characterized using FT-IR spectroscopy and gas chromatography-mass spectrometry (GC-MS), which confirmed that biosurfactants had a lipopeptidic nature. Both biosurfactants were tested against larvae and pupae of A. stephensi. LC₅₀ values were 3.58 (larva I), 4.92 (II), 5.73 (III), 7.10 (IV), and 7.99 (pupae) and 2.61 (I), 3.68 (II), 4.48 (III), 5.55 (IV), and 6.99 (pupa) for biosurfactants produced by B. subtilis A1 and P. stutzeri NA3, respectively. Treatments with bacterial surfactants led to various physiological changes including longer pupal duration, shorter adult oviposition period, and reduced longevity and fecundity. To the best of our knowledge, there are really limited reports on the mosquitocidal and physiological effects due to biosurfactant produced by bacterial strains. Overall, the toxic activity of these biosurfactant on all young instars of A. stephensi, as well as their major impact on adult longevity and fecundity, allows their further consideration for the development of insecticides in the fight against malaria mosquitoes.

1H-Benzo[d]imidazole (BMA) has been considered as an emerging pharmaceutical organic contaminant, leading to the increasing BMA detection in wastewaters and need to be removed from ecosystem. This study investigated a highly synergistic BMA chemisorption using a novel ternary cross-coupled nanohybrid [γ-APTES]-Fe₃O₄@PAN@rGO. Magnetic nanoparticles (Fe₃O₄) were in situ core-shell co-precipitated with polyacrylonitrile polymer (PAN). Then, the prepared Fe₃O₄@PAN was decorated on hexagonal arrays of reduced graphene oxide (rGO) inside the framework of γ-aminopropyltriethoxysilane ([γ-APTES]). The final nanohybrid [γ-APTES]-Fe₃O₄@PAN@rGO produced adjacent inter-fringe distances of 0.2–0.4 nm corresponded well to (111), (220), and (311) parallel sub-lattices with two oblique intersections at 90° right angle and 60° triangle. The BMA adsorption was favorable in neutral pH 7, aroused temperature (50 °C), and controlled by endothermic process. The identified maximum adsorption capacity of 221.73 mg g⁻¹ was 30% higher than the reported adsorbents. The adsorption mechanisms include ion exchange, hydrogen bond, dipole-dipole force, π-conjugation, electrostatic, and hydrophobic interaction. Graphical abstract The synthetic route of novel nanohybrid [γ-APTES]-Fe₃O₄@PAN@rGO was investigated. After BMA adsorption, the adsorbent surface was entirely changed, thus an efficiently facile magnetic separation within 8s. [γ-APTES]-Fe₃O₄@PAN@rGO formed different oblique intersections of 60° and 90° sub-lattices