The Ni-doped and N-doped TiO₂ nanoparticles were investigated for their antibacterial activities on Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) bacteria. Their morphological features and characteristics such as particle size, surface area, and visible light absorbing capacity were compared and discussed. Scanning electron microscopy, X-ray diffraction, and UV–visible spectrophotometry were used to characterize both materials. The inactivation of E. coli (as an example of Gram-negative bacteria) and S. aureus (as an example of Gram-positive bacteria) with Ni-doped and N-doped TiO₂ was investigated in the absence and presence of visible light. Antibacterial activity tests were conducted using undoped, Ni-doped, and N-doped TiO₂. The N-doped TiO₂ nanoparticles show higher antibacterial activity than Ni-doped TiO₂. The band gap narrowing of N-doped TiO₂ can induce more visible light absorption and leads to the superb antibacterial properties of this material. The complete inactivation time for E. coli at an initial cell concentration of 2.7 × 10⁴ CFU/mL was 420 min which is longer than the 360 min required for S. aureus inactivation. The rate of inactivation of S. aureus using the doped TiO₂ nanoparticles in the presence of visible light is greater than that of E. coli. The median lethal dose (LD50) values of S. aureus and E. coli by antibacterial activity under an 18-W visible light intensity were 80 and 350 mg/ml for N-doped TiO₂, respectively.

Arsenic (As) pollution in water has important impacts for human and ecosystem health. In freshwaters, arsenate (Asⱽ) can be taken up by microalgae due to its similarity with phosphate molecules, its toxicity being aggravated under phosphate depletion. An experiment combining ecological and ecotoxicological descriptors was conducted to investigate the effects of Asⱽ (130 μg L⁻¹ over 13 days) on the structure and function of fluvial biofilm under phosphate-limiting conditions. We further incorporated fish (Gambusia holbrooki) into our experimental system, expecting fish to provide more available phosphate for algae and, consequently, protecting algae against As toxicity. However, this protection role was not fully achieved. Arsenic inhibited algal growth and productivity but not bacteria. The diatom community was clearly affected showing a strong reduction in cell biovolume; selection for tolerant species, in particular Achnanthidium minutissimum; and a reduction in species richness. Our results have important implications for risk assessment, as the experimental As concentration used was lower than acute toxicity criteria established by the USEPA.

The degradation of the marine environment is a subject of concern for the European authorities primarily because of its contamination by hydrocarbons. The traditional methods (ISO 11348 standard) of general toxicity assessment are unsuitable in a context of in situ monitoring, such as seaports or bathing zones. Consequently, to address this issue, bacterial biosensors appear to be pertinent tools. This article presents the design of an innovative bioluminescent biosensor dedicated to in situ toxicity monitoring. This biosensor is based on the entrapment of the wild marine bioluminescent bacterial strain Aliivibrio fischeri ATCC® 49387™ in an agarose matrix within a disposable card. A pre-study was needed to select the most biological parameters. In particular, the regenerating medium’s composition and the hydrogel concentration needed for the bacterial entrapment (mechanical resistance) were optimized. Based on these data, the ability of the bacterial reporter to assess the sample toxicity was demonstrated using naphthalene as a chemical model. The biosensor’s results show a lower sensitivity to naphthalene (EC₅₀ = 95 mg/L) compared with the results obtained using the reference method (EC₅₀ = 43 mg/L). With this architecture, the biosensor is an interesting compromise among low maintenance, ease of use, appropriate sensitivity, relatively low cost and the ability to control online toxicity.

Ecosystems offer material and environmental support for human habitation and development in those areas of the earth where people choose to live. However, urbanization is an inexorable trend of human social development and threatens the health of those ecosystems inhabited by humans. This study calculates the values of NPP (net primary productivity), carbon sequestration, water interception, soil conservation, and agricultural production in the Guanzhong-Tianshui Economic Zone. At the same time, we combined DMSP/OLS (Defense Meteorological Satellite Program Operational Line Scanner) night lights remote sensing data and statistical data to analyze the level of urbanization. Quantitative analysis was performed on the interactions between the ecosystem service functions and urbanization based on the calculations of their coupled coordination degrees. The results were the following: (1) The values of NPP, carbon sequestration, and agricultural production showed a trend of increase. However, water interception decreased before increasing, while soil conservation showed the reverse trend; (2) Urbanization levels in the Guanzhong-Tianshui Economic Zone for the last 10 years have proceeded at a fast pace with comprehensive promotion; and (3) Coupled and coupled coordination degrees between urbanization and ecosystem services show increasing trends. This research can provide a theoretical basis for the region’s rapid economic development in the balance.

Hydroponic experiment was conducted to appraise variation in the salt tolerance potential of two wheat cultivars (salt tolerant, S-24, and moderately salt sensitive, MH-97) at different growth stages. These two wheat cultivars are not genetically related as evident from randomized polymorphic DNA analysis (random amplified polymorphic DNA (RAPD)) which revealed 28 % genetic diversity. Salinity stress caused a marked reduction in grain yield of both wheat cultivars. However, cv. S-24 was superior to cv. MH-97 in maintaining grain yield under saline stress. Furthermore, salinity caused a significant variation in different physiological attributes measured at different growth stages. Salt stress caused considerable reduction in different water relation attributes of wheat plants. A significant reduction in leaf water, osmotic, and turgor potentials was recorded in both wheat cultivars at different growth stages. Maximal reduction in leaf water potential was recorded at the reproductive stage in both wheat cultivars. In contrast, maximal turgor potential was observed at the boot stage. Salt-induced adverse effects of salinity on different water relation attributes were more prominent in cv. MH-97 as compared to those in cv. S-24. Salt stress caused a substantial decrease in glycine betaine and alpha tocopherols. These biochemical attributes exhibited significant salt-induced variation at different growth stages in both wheat cultivars. For example, maximal accumulation of glycine betaine was evident at the early growth stages (vegetative and boot). However, cv. S-24 showed higher accumulation of this organic osmolyte, and this could be the reason for maintenance of higher turgor than that of cv. MH-97 under stress conditions. Salt stress significantly increased the endogenous levels of toxic ions (Na⁺ and Cl⁻) and decreased essential cations (K⁺ and Ca²⁺) in both wheat cultivars at different growth stages. Furthermore, K⁺/Na⁺ and Ca²⁺/Na⁺ ratios decreased markedly due to salt stress in both wheat cultivars at different growth stages, and this salt-induced reduction was more prominent in cv. MH-97. Moreover, higher K⁺/Na⁺ and Ca²⁺/Na⁺ ratios were recorded at early growth stages in both wheat cultivars. It can be inferred from the results that wheat plants are more prone to adverse effects of salinity stress at early growth stages than that at the reproductive stage.

Suspended particulate matter trigger the production of reactive oxygen species. However, most of the studies dealing with oxidative damage of airborne particles focus on the effects of individual compounds and not real mixtures. In order to study the enzymatic superoxide production resulting from the exposition to a complex mixture, we derived organic extracts from airborne particles collected daily in an urban area and exposed kidney, liver, and heart mammal tissues. After that, we measured DNA damage employing the comet assay. We observed that in every tissue, NADPH oxidase and xanthine oxidase were involved in O₂ ⁻ production when they were exposed to the organic extracts, as the lucigenin’s chemiluminescence decays when enzymes were inhibited. The same trend was observed with the percentage of cells with comets, since DNA damage was higher when they were exposed to same experimental conditions. Our data allow us to hypothesize that these enzymes play an important role in the oxidative stress produced by PAHs and that there is a mechanism involving them in the O₂ ⁻generation.

High concentrations of soluble Mn in electrolytic manganese solid waste (EMSW) in soil cause the severe contamination in China. Calcium oxide and magnesium oxide-dominated stabilizers are suitable for the solidification/stabilization (s/s) of EMSW. However, the long-term performance of s/s using those two types of stabilizer is problematic. The aim of this study was to develop an accelerated aging method to simulate the long-term natural carbonation of solidified/stabilized EMSW. The joint use of accelerated carbonation, leaching test, mineralogical analysis, and microstructural observation was applied to assess the long-term performance of the s/s EMSW system. On an accelerated carbonation test for solidified/stabilized EMSW, an increase in Mn leaching from 13.6 to 408 mg/kg and a 1.5–2.3 decrease in pH was achieved by using CaO-dominated stabilizers, while an increase in manganese (Mn) from 30 to 266 mg/kg and a decrease in pH of 0.17–0.68 was seen using MgO-dominated stabilizers. CaO+Na₃PO₄ and CaO+CaCO₃ were exceptions in that the leaching value of soluble Mn was lower after carbonation. Mineralogical analysis showed that rhodochrosite in the carbonated s/s system was generated not only from the reduction of hausmannite but also from the reversible reaction between Mn(OH)₂ and MnCO₃. Carbonation destroyed the tight particle structure resulting in a porous and loose structure. As for s/s EMSW treated by MgO-dominated stabilizers, carbonation affected the agglomerating structure and mineralogical composition by increasing magnesium (Mg) migration, thereby forming hydromagnesite that had weak binding ability and a nested porous shape. Therefore, carbonation by itself does not cause deterioration to s/s products of the soluble Mn but does have significant effects on the microstructure and mineralogical composition. It is recommended to add Na₃PO₄ or CaCO₃ into a single CaO stabilized EMSW system to prevent aging of the system, allow formation of Mn phosphate precipitates, and improve the absorption and oxidation of soluble Mn(II).

In the present study, the field dissipation and transport of quizalofop-p-ethyl by water and sediment runoff were investigated in sunflower experimental cultivation under Mediterranean conditions. The cultivation was carried out in silty clay soil plots with two different slopes of 1 and 5 %. The soil dissipation rate of quizalofop-p-ethyl was fast and can be described by both single first-order (SFO) and Gustafson and Holden (first-order multi compartment (FOMC)) kinetics. The half-life of quizalofop-p-ethyl ranged from 0.55 to 0.68 days and from 0.45 to 0.71 days when SFO and FOMC kinetics were applied, respectively. No herbicide residues were detected below the 10-cm soil layer. A single detection of quizalofop-p-ethyl was observed in runoff water (3 days after application (DAA)) at relatively low concentrations (from 1.70 to 2.04 μg L⁻¹). In sediment, it was detected in the samplings of 3 and 25 DAA at concentrations that never exceeded 0.126 μg g⁻¹. The estimated total losses of quizalofop-p-ethyl as percentage of the initial applied active ingredient were low both in water and sediment (less than of 0.021 and 0.005 %, respectively). Quizalofop-p-ethyl residues were detectable for 18 DAA in the stems and leaves of the plants and 6 DAA in the root system. No herbicide residues were detected in inflorescences and seeds of sunflower plants. Experimental data showed minimal risk for the contamination of soil and adjacent water bodies.

The comparative effectiveness for hexavalent chromium removal from irrigation water, using two selected plant species (Phragmites australis and Ailanthus altissima) planted in soil contaminated with hexavalent chromium, has been studied in the present work. Total chromium removal from water was ranging from 55 % (Phragmites) to 61 % (Ailanthus). After 360 days, the contaminated soil dropped from 70 (initial) to 36 and 41 mg Cr/kg (dry soil), for Phragmites and Ailanthus, respectively. Phragmites accumulated the highest amount of chromium in the roots (1910 mg Cr/kg₍dᵣy ₜᵢₛₛᵤₑ₎), compared with 358 mg Cr/kg₍dᵣy ₜᵢₛₛᵤₑ₎ for Ailanthus roots. Most of chromium was found in trivalent form in all plant tissues. Ailanthus had the lowest affinity for Crⱽᴵ reduction in the root tissues. Phragmites indicated the highest chromium translocation potential, from roots to stems. Both plant species showed good potentialities to be used in phytoremediation installations for chromium removal.

The work highlights the utilization of an agricultural waste mustard plant ash (MPA) as a soil additive and an adsorbent. MPA was characterized by X-ray fluorescence (XRF), energy-dispersive X-ray spectroscopy (EDX), proximate analysis, CHNS analysis, Brunauer–Emmett–Teller (BET) surface area analysis, zeta potential measurements, Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). XRF analysis confirmed the presence of CaO (31.35 %), K₂O (18.55 %), and P₂O₅ (6.99 %), all of which act as micronutrients to plants. EDX also confirms high amount of elemental O, Ca, K, and P. The adsorptive ability of MPA was investigated using a commonly used herbicide, 2,4-dichlorophenoxyacetic acid (2,4-D), as a representative chemical. Batch adsorption experiments were conducted to study the effect of different operational parameters such as adsorbent dose, initial 2,4-D concentration, contact time, and temperature on the adsorption process. Data from experiments were fitted to various kinetic and isothermal models. The pseudo-second-order kinetic model was found to show the best fit (R ² > 0.99), with the highest k ₂ value of the order 10⁵. Based on the study results, dosage of MPA/hectare for different crops has been recommended for effective removal of 2,4-D. To our knowledge, this is the first study in which MPA has been characterized in detail and investigated for dual applications (as an adsorbent and as a soil additive).