Acinetobacter guillouiae SFC 500-1A, a native bacterial strain isolated from tannery sediments, is able to simultaneously remove high concentrations of Cr(VI) and phenol. In this complementary study, high-resolution microscopy techniques, such as atomic force microscopy (AFM) and transmission electron microscopy (TEM), were used to improve our understanding of some bacterial adaptive mechanisms that enhance their ability to survive. AFM contributed in gaining insight into changes in bacterial size and morphology. It allowed the unambiguous identification of pollutant-induced cellular disturbances and the visualization of bacterial cells with depth sensitivity. TEM analysis revealed that Cr(VI) produced changes mainly at the intracellular level, whereas phenol produced alterations at the membrane level. This strain tended to form more extensive biofilms after phenol treatment, which was consistent with microscopy images and the production of exopolysaccharides (EPSs). In addition, other exopolymeric substances (DNA, proteins) significantly increased under Cr(VI) and phenol treatment. These exopolymers are important for biofilm formation playing a key role in bacterial aggregate stability, being especially useful for bioremediation of environmental pollutants. This study yields the first direct evidences of a range of different changes in A. guillouiae SFC 500-1A which seems to be adaptive strategies to survive in stressful conditions.

In the current study, water quality of five river sites in Parana River basin (Brazil), utilized for public water supply, was assessed through a set of biomarkers in fish Astyanax spp. Population growth and inadequate use of land are challenges to the preservation of biodiversity and resources such as water. Some physicochemical parameters as well as somatic indexes, gills and liver histopathology, genotoxicity, and biochemical biomarkers were evaluated. The highest gonadosomatic index (GSI) and antioxidant parameters (catalase and glutathione S-transferase activities, non-protein thiols), as well as the lowest damage to biomolecules (lipid peroxidation, protein carbonylation, DNA damage) were observed in site 0 (Piava River), which is located at an environmental protected area. Site 1, located in the same river, but downstream site 0 and outside the protection area, presents some level of impact. Fish from site 2 (Antas River), which lack of riparian forest and suffer from silting, presented the highest micronucleus incidence and no melanomacrophages. Differently, individuals from site 3 (Xambrê River) and site 4 (Pinhalzinho River) which receive surface runoff from Umuarama city, urban and industrial sewage, have the highest incidences of liver and gill histopathological alterations, including neoplasia, which indicated the worst health conditions of all sites. In particular, site 4 had high levels of total nitrogen and ammonia, high turbidity, and very low oxygen levels, which indicate important chemical impact. Comparison of the biomarkers in fish allowed classification of the five sites in terms of environmental impact and revealed that sites 3 and 4 had particular poor water quality.

Troposphere ozone, which is from secondary formation processes, has been increasing dramatically during the last decades in China, inducing high health risks. In this study, temporal and spatial distribution of O₃ was studied among 13 sites of three cities during 2014–2016. The objectives were to clarify the characteristics of the ambient pollution of O₃ under the influence from other pollutants and meteorological parameters and the health outcomes from exposure to O₃. The concentrations of O₃ during summer were much higher than those during winter, and the concentrations in downtown areas were higher than in rural or mountain areas. PM₂.₅, NO₂, SO₂, and wind speed (WS) were negatively correlated with O₃, and CO, temperature (T), and relative humidity (RH) were positively correlated with O₃. In multivariable analysis, two separate factors—solar radiation and atmospheric diffusion status, affected the O₃ levels. The concentrations of O₃ reached the highest level at 15:00 and the lowest value at about 6:00–8:00, with the similar trend to T and WS, and opposite to RH. According to the dose-response model, relative risks (RRs) and population attributable fractions (PAFs) with confidence intervals (CIs) for chronic obstructive pulmonary disease (COPD) from exposure to O₃ were 1.0612 (CI 1.0607–1.0616) and 5.32% (CI 5.29–5.36%), respectively, attributable to 2000 deaths in Zhejiang Province in 2014.

This work focused on the development and validation of methodologies for the accurate determination of mercury in environmental samples and its further application for the preparation and certification of new reference materials (RMs). Two certified RMs ERM-CC580 (inorganic matrix) and ERM-CE464 (organic matrix) were used for the evaluation of digestion conditions assuring the quantitative recovery of mercury. These conditions were then used for the digestion of new candidates for the environmental RMs: bottom sediment (M_2 BotSed), herring tissue (M_3 HerTis), cormorant tissue (M_4 CormTis), and codfish muscle (M_5 CodTis). Cold vapor atomic absorption spectrometry (CV AAS) and inductively coupled plasma mass spectrometry (ICP MS) were used for the measurement of mercury concentration in all RMs. In order to validate and assure the accuracy of results, isotope dilution mass spectrometry (IDMS) was applied as a primary method of measurement, assuring the traceability of obtained values to the SI units: the mole, the kilogram, and the second. Results obtained by IDMS using n(²⁰⁰Hg)/n(²⁰²Hg) ratio, with estimated combined uncertainty, were as follows: (916 ± 41)/[4.5 %] ng g⁻¹ (M_2 BotSed), (236 ± 14)/[5.9 %] ng g⁻¹ (M_3 HerTis), (2252 ± 54)/[2.4 %] ng g⁻¹ (M_4 CormTis), and (303 ± 15)/[4.9 %] ng g⁻¹ (M_CodTis), respectively. Different types of detection techniques and quantification (external calibration, standard addition, isotope dilution) were applied in order to improve the quality of the analytical results. The good agreement (within less than 2.5 %) between obtained results and those derived from the Inter-laboratory Comparison, executed by the Institute of Nuclear Chemistry and Technology (Warsaw, Poland) on the same sample matrices, further validated the analytical procedures developed in this study, as well as the concentration of mercury in all four new RMs. Although the developed protocol enabling the metrological certification of the reference value was exemplified by the determination of mercury in environmental samples, it could be considered as valid for any certification procedure required whenever new certified RMs are introduced.

Biodegradation of pyridine and quinoline is initiated with mono-oxygenation reactions that require an intracellular electron donor. Simultaneous biodegradation of both substrates should set up competition for the intracellular electron donor that may inhibit one or more of the mono-oxygenation steps. An internal circulation baffled biofilm reactor (ICBBR) was used to evaluate the impacts of competition during pyridine and quinoline biodegradation. Compared with independent biodegradation, pyridine and quinoline removal rates were slowed when biodegraded simultaneously, although the pyridine removal rate decreased more than for quinoline. The first mono-oxygenation of quinoline (to 2-hydroxyquinoline) always was faster than the first mono-oxygenation of pyridine (to 2-hydroxypyridine), and the difference was accentuated with pyridine and quinoline which were biodegraded simultaneously due to the competition for intracellular electron donor. Competition also existed between the second mono-oxygenations, and the removal rate of 2-hydroxypyridine was faster than the rate for 2-hydroxyquinoline, even though the rate was faster for quinoline than pyridine. Adding an exogenous electron donor accelerated all mono-oxygenations in proportion to the amount of donor added, but the increments were greater for quinoline due to its higher affinity for intracellular electron donors than pyridine. When actual coking wastewater was used as the background matrix, removals of pyridine and quinoline exhibited the same competitive trends.

Currently, public pay more attention to the adverse effect of organophosphate pesticides on human and animal health and on the environment in developing nations. Vitamin E may protect the hepatocyte and increase the function of liver. The study was to investigate the effects of phoxim-induced hepatotoxicity on Sprague Dawley (SD) rats and the protection of vitamin E. SD rats received by gavage 180 mg kg⁻¹ (per body weight) of phoxim, 200 mg kg⁻¹ (per body weight) of vitamin E, and phoxim + vitamin E. The results showed that exposure to phoxim elevated liver coefficient; glutamyl transpeptidase (GGT), aspartate aminotransferase, alkaline phosphatase, total bilirubin, total bile acid, and alanine aminotransferase in the serum; ROS in the liver; and the expression of p53, Bax, CYP2E1, ROS, caspase-9, caspase-8, and caspase-3, while phoxim caused a reduction of total protein, albumin, and cholinesterase in the serum; acetylcholinesterase, total antioxidant capacity, glutathione peroxidase, and glutathione in the liver; and the expression of Bcl-2. Vitamin E modified the phoxim-induced hepatotoxicity by reducing the GGT in the serum, malondialdehyde in the liver, and the expression of CYP2E1 significantly. There were no significant changes of globulin in the serum, the activity of catalase in the liver, as well as expression levels of Fas and Bad in the liver. Overall, subacute exposure to phoxim induced hepatic injury, oxidative stress damage, and cell apoptosis. Vitamin E modified phoxim-induced hepatotoxicity slightly. And, vitamin E minimized oxidative stress damage and ultrastructural changes in rat hepatocytes notably.

Designing of advanced oxidation process (AOP) requires knowledge of the aqueous phase hydroxyl radical (●OH) reactions rate constants (k OH), which are strictly dependent upon the pH and temperature of the medium. In this study, pH- and temperature-dependent quantitative structure-property relationship (QSPR) models based on the decision tree boost (DTB) approach were developed for the prediction of k OH of diverse organic contaminants following the OECD guidelines. Experimental datasets (n = 958) pertaining to the k OH values of aqueous phase reactions at different pH (n = 470; 1.4 × 10⁶ to 3.8 × 10¹⁰ M⁻¹ s⁻¹) and temperature (n = 171; 1.0 × 10⁷ to 2.6 × 10¹⁰ M⁻¹ s⁻¹) were considered and molecular descriptors of the compounds were derived. The Sanderson scale electronegativity, topological polar surface area, number of double bonds, and halogen atoms in the molecule, in addition to the pH and temperature, were found to be the relevant predictors. The models were validated and their external predictivity was evaluated in terms of most stringent criteria parameters derived on the test data. High values of the coefficient of determination (R ²) and small root mean squared error (RMSE) in respective training (> 0.972, ≤ 0.12) and test (≥ 0.936, ≤ 0.16) sets indicated high generalization and predictivity of the developed QSPR model. Other statistical parameters derived from the training and test data also supported the robustness of the models and their suitability for screening new chemicals within the defined chemical space. The developed QSPR models provide a valuable tool for predicting the ●OH reaction rate constants of emerging new water contaminants for their susceptibility to AOPs.

Despite the environmental risks posed by microplastic pollution, there are presently few standardized protocols for monitoring these materials within marine and coastal habitats. We provide a robust comparison of methods for sampling microplastics on sandy beaches using pellets as a model and attempt to define a framework for reliable standing stock estimation. We performed multiple comparisons to determine: (1) the optimal size of sampling equipment, (2) the depth to which samples should be obtained, (3) the optimal sample resolution for cross-shore transects, and (4) the number of transects required to yield reproducible along-shore estimates across the entire sections of a beach. Results affirmed that the use of a manual auger with a 20-cm diameter yielded the best compromise between reproducibility (i.e., standard deviation) and sampling/processing time. Secondly, we suggest that sediments should be profiled to a depth of at least 1 m to fully assess the depth distribution of pellets. Thirdly, although sample resolution did not have major consequence for overall density estimates, using 7-m intervals provides an optimal balance between precision (SD) and effort (total sampling time). Finally, and perhaps most importantly, comparing the minimum detectable difference yielded by different numbers of transects along a given section of beach suggests that estimating absolute particle density is probably unviable for most systems and that monitoring might be better accomplished through hierarchical or time series sampling efforts. Overall, while our study provides practical information that can improve sampling efforts, the heterogeneous nature of microplastic pollution poses a major conundrum to reproducible monitoring and management of this significant and growing problem.

Sulfur dioxide (SO₂) is considered as a main air pollutant in industrialized areas that can damage vegetation. In the present study, we investigated how exposure to SO₂ and foliar application of iron (Fe) would affect certain physiological characteristics of Plantago major. The plant seedlings exposed or unexposed to SO₂ (3900 μg m⁻³) were non-supplemented or supplemented with Fe (3 g L⁻¹) as foliar spray. Plants were exposed to SO₂ for 6 weeks in 100 × 70 × 70 cm chambers. Fumigation of plants with SO₂ was performed for 3 h daily for 3 days per week (alternate day). Lower leaf Fe concentration in the plants exposed to SO₂ at no added Fe treatment was accompanied with incidence of chlorosis symptoms and reduced chlorophyll concentration. No visible chlorotic symptoms were observed on the SO₂-exposed plants supplied with Fe that accumulated higher Fe in their leaves. Both at with and without added Fe treatments, catalase (CAT) and peroxidase (POD) activity was higher in the plants fumigated with SO₂ in comparison with those non-fumigated with SO₂. Foliar application of Fe was also effective in increasing activity of antioxidant enzymes CAT and POD. Exposure to SO₂ led to reduced cellulose but enhanced lignin content of plant leaf cell wall. The results obtained showed that foliar application of Fe was effective in reducing the effects of exposure to SO₂ on cell wall composition. In contrast to SO₂, application of Fe increased cellulose while decreased lignin content of the leaf cell wall. This might be due to reduced oxidative stress induced by SO₂ in plants supplied with Fe compared with those unsupplied with Fe.

The present study deals with the use of low-cost plant-derived materials, namely a biochar, spent coffee grounds, spent tea leaves, and a compost humic acid, for the adsorptive removal from water of two estrogens, 4-tert-octylphenol (OP) and 17-β-estradiol (E2), and two pesticides, carbaryl and fenuron, each spiked at a concentration of 1 mg L⁻¹. Kinetics and adsorption isotherms have been performed using a batch equilibrium method to measure the sorption capacities of the adsorbents towards the four molecules. Adsorption constants were calculated using the linear, Freundlich, and Langmuir models. Kinetics data obtained evidenced a rapid adsorption of each compound onto both biochar and coffee grounds with the attainment of a steady-state equilibrium in less than 4 h. Significant differences among the adsorbents and the compounds were found regarding the model and the extent of adsorption. In general, the estrogens were adsorbed more quickly and in greater amounts than the less hydrophobic pesticides, following the order: OP > E2 > carbaryl > fenuron. The ranges of Freundlich constants obtained for OP, E2, carbaryl, and fenuron onto the sorbents were 5049–2253, 3385–206, 2491–79, and 822–24 L kg⁻¹, respectively. The maximum values of constants were obtained for biochar, except for OP that was more adsorbed by spent coffee grounds. Adsorption kinetic data followed a pseudo-second-order model, thus indicating the occurrence of chemical interactions between the compounds and the substrates. The remarkable sorption capacities of all adsorbents towards the four molecules suggest the valuable exploitation of these materials for decontamination purposes, such as the treatment of wastewater before a feasible recycle in soil.