In French Guiana, native populations present high level of mercury contamination, which has been linked to the consumption of contaminated fishes. The goal of this study is to undertake a cartography of mercury contamination levels in fishes from the six main Guiana rivers. The selected species for this study is the ubiquitous piscivorous fish Hoplias aimara. A total number of 575 fishes from 134 discrete fishing sites are regrouped into 51 river sectors. Results from this study permits to rank the six main Guiana rivers by their mean level of contamination: Oyapock (0.548 mg kg⁻¹), Comté (0.624 mg kg⁻¹), Maroni (0.671 mg kg⁻¹), Approuague (0.684 mg kg⁻¹), Mana (0.675 mg kg⁻¹), and Sinnamary (1.025 mg kg⁻¹). The contamination is however not spatially homogenous along each river, and a map of the different levels of mercury contamination in fishes is provided. Sectors of low mean Hg contamination are observed both upstream (0.471 mg kg⁻¹) and downstream (0.424 mg kg⁻¹), corresponding to areas without any influence of gold mining activities and areas under the influence of estuarine dilution, respectively. Anoxia and gold mining activities are found to be the two main factors responsible for the high mercury concentration in fish muscles. While mean levels of mercury contaminations are higher in anoxia areas (1.029 mg kg⁻¹), contaminations induced by gold mining activities (0.717 mg kg⁻¹) present the most harmful consequences to human populations. No significant differences in Hg concentrations are observed between 2005 and 2014 for neither a pristine nor a gold mining area, while Hg concentration differences are observed between former (0.550 mg kg⁻¹) and current gold mining sites (0.717 mg kg⁻¹).

Phytoremediation has been proposed as a potential biotechnological strategy to remediate effluents before their release into the environment. The use of common aquatic plant species, such as macrophytes (e.g., Lemna spp.) as a cleanup solution has been proposed decades ago. However, the effectiveness of such processes must be assessed by analyzing the toxicity of resulting effluents, for the monitoring of wastewater quality. To attain this purpose, this work intended to quantify the efficacy of a Lemna-based wastewater phytoremediation process, by analyzing toxicological effects of domestic and textile effluents. The toxic effects were measured in Lemna minor (same organisms used in the phytoremediation process, by quantifying toxicological endpoints such as root length, pigment content, and catalase activity) and by quantifying individual parameters of Daphnia magna (immobilization, reproduction, and behavior analysis). Phytoremediation process resulted in a decrease of chemical oxygen demand in both effluents and in an increase in root length of exposed plants. Moreover, textile effluent decreased pigments content and increased catalase activity, while domestic effluent increased the anthocyanin content of exposed plants. D. magna acute tests allowed calculating a EC₅₀ and Toxic Units interval of 53.82–66.89%/1.85–1.49, respectively, to raw textile effluent; however, it was not possible to calculate these parameters for raw and treated domestic effluent (RDE and TDE). Therefore, in general, the acute toxicity of effluent toward D. magna was null for RDE, and mild for the treated textile effluent (TTE), probably due to the effect of phytoremediation. Exposure to textile effluents (raw and treated) increased the total number of neonates of D. magna and, in general, both textile effluents decreased D. magna distance swim. Moreover, although both effluents were capable of causing morphological and physiological/biochemical alterations in L. minor plants, organisms of this species were able to survive in the presence of both effluents and to remediate them.

Cleome amblyocarpa Barr. and Murb is a medicinal plant widespread in North Africa and widely used in Tunisia to treat diabetes and colic. The non-volatile (polyphenols, flavonoids, tannins, and flavonols) and volatile compounds (GC-MS) of C. amblyocarpa leaves and stems have been studied. The antioxidant, antimicrobial, analgesic, and cytotoxic activities of hydroalcoholic extracts of C. amblyocarpa leaves and stems were also investigated. The major volatile components were β-caryophyllene (46.9%), eugenol (25.6%), ethyl 3-methylpentanoate (16.2%), 7-epi-silphiperfol-5-ene (11.0%), and α-copaene (7.0%). The antioxidant activity has been evaluated using various in vitro assays, such as DPPH free radical scavenging activity, iron-chelating capability, and ability to inhibit lipid peroxidation (TBARS). The antibacterial and antifungal effectiveness of leaves and stems parts of Cleome amblyocarpa were investigated by means of the disc diffusion and microdilution techniques. The in vitro cytotoxicity of the hydroalcoholic extract of C. amblyocarpa on A549 and H1299 lung adenocarcinoma cells was determined using the crystal violet assay. The acute toxicity of the extracts on Swiss albino mice at the doses of 3000, 1500, and 500 mg/kg body weight was evaluated. The analgesic effect of leaves and stems extract was also determined by means of the acetic acid induced writhing test. The results indicated that the leaves have higher phenols, and flavonoids contents and potential antioxidant, antimicrobial, and anticancer activities in comparison to stem. In addition, the aerial part of C. amblyocarpa did not cause signs of toxicity or death in animals at doses up to 3000 mg/kg and have a significant analgesic activity.

In this study, an internal circulation biological aerated filter (ICBAF) reactor was applied to pretreat refinery wastewater containing large amounts of organic pollutants. According to the composition change of inlet-and-outlet water, the main organic pollutants, including micromolecular organic-acids, aldehydes, ketones, phenols, and so forth, degraded well in ICBAF unit. The concentration of organic acids, alcohols, and esters changed from 648 to 90 mg/L, 130 to 90 mg/L, and 158 to 228 mg/L, respectively. The average removal efficiencies of chemical oxygen demand (COD) and biological oxygen demand (BOD₅) reached 54.62% and 83.64%, respectively. It was clear that the concentration of effluent organic acids in the ICBAF unit decreased significantly. The degradation process of organic acids, alcohols, and esters (among others) and the degradation pathway of organic acids were also discussed. Straight chain organic acids and naphthenic acids were degraded by α-oxidation, β-oxidation, α- and β-combined oxidation, or aromatization. The study demonstrates the potential of the ICBAF as an alternative for the high-efficiency pretreatment of refinery wastewater.

Spinel ferrite particles (Fe₃O₄, MnFe₂O₄, and CoFe₂O₄) were investigated as magnetic nanosorbents for removing arsenic from spiked water samples. The nanosorbents were collected via magnetic separation from aqueous solutions spiked with an arsenic concentration that mimics the amount of this contaminant in real water samples. This research shows that using amounts of CoFe₂O₄ or MnFe₂O₄ as low as 40 mg/L, the arsenic content in the contaminated water decreased for levels below the maximum admitted value by the World Health Organization for drinking waters (10 μg/L). Moreover, these magnetic nanosorbents also showed good performance for As(V) sorption, when applied to aqueous matrices with variable ionic strength and in the mixtures of other several hazardous contaminants. The good performance observed for the MnFe₂O₄ and CoFe₂O₄ ferrites contrasts with the one observed for Fe₃O₄ nanosorbent, whose efficiency is lower in the removal of As(V) from water, nevertheless increased with the presence of other elements in solution.

The uptake and distribution of four heavy metals, including copper (Cu), cadmium (Cd), lead (Pb) and zinc (Zn), and those of total phosphorus (TP) in 30 plants in North China were investigated through pot trial experiments. Accumulation and distribution of heavy metals or TP were associated with plant species, tissues, metal elements and pollutant loading. The highest amount of heavy metal and TP accumulation was found in the whole plants of Hylotelephium erythrostictum (Miq.) H. Ohba (C1) and Chlorophytum laxum R. Br. (L4), respectively. Considering the biological concentration factor, translocation factor, retention factor and biomass indices, C1 is the suitable plant for Cd and Cu uptake, whereas Hosta plantaginea (Lam.) Aschers (L3) and Viola verecunda A. Gray (V1) are the suitable plants for Pb removal. Rehmannia glutinosa (Gaetn.) Libosch. ex Fisch. (S1) and L4 can be chosen for Zn and TP removal, respectively. Cluster analysis was applied to select suitable plants for heavy metal and TP removal. Results showed that C1, L4 and Pennisetum alopecuroides (L.) Spreng (G1) have a good capability of accumulating heavy metals and TP. Results demonstrated that the plant species rather than the families considerably influenced the accumulation of pollutants.

Monosodium glutamate (MSG) is widely used as food additive and flavor enhancer; however, consumption of high dose of MSG provokes oxidative stress in many organs and its safety and side effects on the body are still controversial. Therefore, it is crucial to investigate the long-lasting effects of MSG on cardiac muscle functions and structure. Forty male Wister albino rats were assigned into 3 groups. Control group was injected intraperitoneally with physiological saline for 7 days. Second group was injected intraperitoneally with MSG at a dose of 4 mg/g b.w/day for 7 consecutive days and then kept without any treatment till 45th day of the experiment. Third group was injected intraperitoneally with MSG at a dose of 6 mg/g b.w/day for 7 consecutive days and then kept without any treatment till 45th day of the experiment. Monosodium glutamate significantly reduced body weight, force of cardiac muscle contractility, serum level of high-density lipoprotein, and superoxide dismutase activity in cardiac muscle, while it significantly elevated heart rate, serum levels of total cholesterol, low-density lipoprotein, triacylglycerides, atherogenic index and troponin T, activities of serum lactate dehydrogenase and creatine kinase-MB, malondialdehyde concentration, and P53 protein expression in cardiac muscle. In addition, it induced myocardial degeneration, cellular infiltration, deposition of collagen in cardiac muscle, and periodic acid–Schiff staining reaction. This study indicated that MSG exerted long-lasting functional and structural alterations in the heart of male albino rats through induction of oxidative stress, atherogenesis, and apoptosis.

Catalytic wet peroxide oxidation (CWPO) is a novel, alternative technology to conventional disinfection methods that are widely used to control microbial parameters in drinking water. To assess its effectiveness, new studies revealing the kinetics of MS2 coliphage inactivation by CWPO technology are required. This investigation therefore aimed to perform mathematical modelling of MS2 inactivation through CWPO technology activated by an Al/Fe-pillared clay catalyst (Al/Fe-PILC) in the presence of a synthetic surrogate of dissolved natural organic matter. The inactivation constant was obtained from two different statistical approaches, and the experimental data were better fitted to the pseudo-first-order Chick-Watson model in which the inactivation rate is constant. For this model, the maximum inactivation rate was k = 0.1648 min⁻¹, which was achieved in the MS2-3 catalytic test using an initial mass ratio of peroxide to active iron (Feₐcₜ) of 1.2 mg H₂O₂/mg Feₐcₜ. To estimate the inactivation rate due to reactive oxygen species (ROS), we supposed that the inactivation constant depends on both ROS and Feₐcₜ. In this case, the maximum inactivation rate due to ROS was kᵣ = 2.4 × 10⁻⁹ min⁻¹ (using 1.17 mg H₂O₂/mg Feₐcₜ), which was achieved in the MS2-10 trial; both cases led to the conclusion that the optimal initial ratio of peroxide to active Fe in the catalyst in CWPO activated by Al/Fe-PILC was close to 1.2 mg H₂O₂/mg Feₐcₜ. These kinetic studies showed that rapid inactivation takes place very early in the reaction, followed by slow inactivation during the remaining period of the recorded reaction time. This research revealed the strong potential of CWPO technology to improve microbiological parameters in drinking water due to the high catalytic performance in the heterogeneous Fenton reaction displayed by Fe sites incorporated in the Al/Fe-PILCs.

Identifying environmental consequences of international trade has a crucial role in constructing and planning strategies of any country, especially in developing countries that are currently witnessing a significant increase in trade openness; however, little efforts are made to investigate the environmental consequences of trade openness. The paper attempts to investigate the dynamic relationship between trade openness and environmental pollutants incorporating potential factors affecting environmental quality in 66 developing economies over the period 1971–2017. This article employs the powerful approach two-step generalized method of moment’s estimators with a finite sample correction to obtain more accurate inference. The key empirical results are as follows: (1) trade openness may be harmful for the environment while confirming the existence of an environmental Kuznets curve hypothesis. (2) An increase in pollutants, namely carbon dioxide emissions, ambient particulate matter and nitrous oxide emissions in the previous period, is associated with a rise in pollutants in the future suggesting that if no action in reducing pollutants is taken, environmental quality is worse. (3) Energy consumption, financial development and industrialization have a significant contribution to deteriorating environment. The implications of these results also are discussed and proposed for developing economies in this research.

This study was concerned with the temporal analysis of benzene, toluene, ethylbenzene, xylenes (BTEXs), and ozone in Rochester, New York, between 2012 and 2018. Additionally, the influence of ozone precursors (e.g., BTEXs and NO₂) and meteorological variables (e.g., relative humidity (RH), temperature along with wind speed) on ozone dispersion was investigated in the eastern half of the USA using the integrated nested Laplace approximation and stochastic partial differential equation (INLA-SPDE). The benzene variability at seasonal scale was characterized by higher values during the cold seasons. On the contrary, the long-term temporal trend of ozone depicted a repetitive cyclic behavior while an episode, with values exceeding 5 μg/m³, was detected associated with benzene in 2015. The spatial analysis by INLA-SPDE indicated that 1,3,5-trimethylbenzene and benzene were the key ozone precursors influencing ozone formation. It was demonstrated that increase of temperature had a considerable impact on ozone build-up whereas the increment of RH leads to decrease in ambient values of ozone. The amounts of root mean squared error (RMSE), mean absolute error (MAE), and bias for the validation data (e.g., 32 samples) were 0.005, 0.004, and 0.0008, exhibiting a reasonable out-of-sample forecasting by the INLA-SPDE model. The distribution map of ozone highlighted a hot spot in the state of Florida.