The present study aimed at investigating cytotoxicity and oxidative stress induced by silica-coated iron oxide nanoparticles functionalized with dithiocarbamate (Fe₃O₄ NPs) in Chinook salmon cells (CHSE-214) derived from Oncorhynchus tshawytscha embryos. A significant reduction in cell viability was evident in response to Fe₃O₄ NPs as revealed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay after 24 h of exposure. Out of the tested concentrations (10, 20, and 30 μg/ml), the highest concentration has shown significant decrease in the viability of cells after 24 h of exposure. Alterations in the morphology of CHSE-214 cells was also evident at 10 μg/ml concentration of Fe₃O₄ NPs after 24 h. Fe₃O₄ NPs elicited a significant dose-dependent reduction in total glutathione content (TGSH), catalase (CAT), glutathione reductase (GR) with a concomitant increase in lipid peroxidation (LPO), and protein carbonyl (PC) at highest concentration (30 μg/ml) after 24 h of exposure. In conclusion, our data demonstrated that Fe₃O₄ NPs have potential to induce cytotoxicity in CHSE-214 cells, which is likely to be mediated through reactive oxygen species generation and oxidative stress.

The objectives of the research are to determine the occurrence of pharmaceuticals in surface water and groundwater in the Republic of Serbia and to identify significant effects of river-water purification through riverbank filtration, concerning oxic conditions and hydrogeological conditions of alluvial aquifers in Serbia. Between 2009 and 2015, a total of 19 studied pharmaceuticals and metabolites were analyzed in 184 samples, 10 were detected in surface water, and 8 in groundwater. Carbamazepine and metamizole metabolites N-acetyl-4-amino-antipyrine (4-AAA) and N-formyl-4-amino-antipyrine (4-FAA) have the highest frequency of occurrence in surface water (57.3–68.8 %) and in groundwater (19.5–43.9 %), respectively. Highest detected concentrations were for 4-AAA (520 ng/L) and 4-FAA (248 ng/L) in surface water as well as in groundwater (4-AAA 128 ng/L and 4-FAA 150 ng/L). Results showed that riverbank filtration sites with different hydrogeological and oxic conditions could significantly remove investigated pharmaceuticals. Percentage of removal during riverbank filtration was determined for carbamazepine (65.4 %), trimethoprim (100 %), 4-AAA (91.2 %), and 4-FAA (70 %) for all investigated locations. Based on the available data for three specific locations (Danube River alluvion, Sava River alluvion, and Velika Morava River alluvion), results showed that besides oxic conditions, residence time of groundwater in alluvial aquifer and ratio of infiltrated water from river to the well play very important role in the quality of groundwater. These results are extremely important for better understanding of self-purification potential of alluvial aquifers and protection from potential impacts of anthropogenic pollution to the groundwater sources in the Republic of Serbia.

The concentration characteristics, sources, and potential ecological risk assessment of 16 PAHs were investigated in the surface water from the Songhua River Basin, Northeast China. A total of 48 river water samples, including 16 from the main streams and 32 from the tributaries, were collected. Samples were separated into dissolved phases and suspended particle matter (SPM) via filtration with 0.47 μm glass fiber filters. Each phase was analyzed for PAHs. The total PAH concentration in the dissolved phase in the water ranged from 32.5 to 108 ng L⁻¹ and from 0.3 to 62.3 μg g⁻¹ (dry weight) in the suspended particle matter (SPM). The total PAH concentration in the main stream was lower than in the tributaries; the volume of annual runoff of rivers had a significant effect on the ƩPAH in the rivers. The 2- and 3-ring PAHs dominated in both the dissolved phase and SPM, indicating a relatively recent local source of PAHs in the study area. The concentrations of PAHs in the Songhua River Basin are lower when compared with the values previously reported in the literature from other rivers around the world. The sources of PAHs were assessed by diagnostic ratios and principal component analysis (PCA), and the ecological risk of the PAHs was assessed based on the risk quotient (RQ). The diagnostic ratios and PCA indicated that the main sources of PAHs originated from pyrogenic and petrogenic sources, and pyrogenic sources had a greater impact. The ecological risk assessment indicated that the PAHs presented low ecosystem risk in the Songhua River Basin.

Co-, Ce-, and Ni-doped carbon xerogels (Me-CX) synthesized by sol-gel method followed by an ion exchange process were used as catalysts for catalytic wet air oxidation (CWAO) of phenol. The prepared catalysts were characterized using TEM, SEM, BET surface area, and XRD. Me-CX catalysts were tested in mild conditions (20–60 °C, atmospheric pressure) in a semi-batch reactor in various reaction conditions (30–60 L/h, 0.05–0.2 g catalysts, 50–175 mg phenol/L). Total organic carbon (TOC) removal efficiency values obtained decrease in the following order Co-CX ≅ Ce-CX > Ni1-CX > K-CX for the catalysts obtained using the same procedure. TOC removal efficiencies of up to 72% were reached in case of Co-CX catalyst at 20 °C, 40 L/h, using 0.15 g catalyst and a solution of 100 mg phenol/L.

This greenhouse study examined the use of organic and inorganic soil amendments in waste rock material from the former Questa Molybdenum Mine in northern New Mexico to promote beneficial soil properties. Waste rock material was amended with 11 soil amendment treatments that included municipal composted biosolids, Biosol®, inorganic fertilizer, and two controls (pure waste rock and sand). Elymus trachycaulus and Robinia neomexicana growth performance and plant chemistry were assessed across all treatments over a period of 99 and 141 days, respectively. Even though waste rock material had more than 200 times the molybdenum concentration of native soils, adverse effects were not observed for either species. The two main limiting factors in this study were soil nutritional status and soil water retention. The biosolid amendment was found to provide the greatest buffer against these limiting factors due to significant increases in both nutrition and soil water retention. As a result, both species responded with the highest levels of biomass production and the least amount of required water demands. Use of organic amendments such as biosolids, even though short lived in the soil, may provide plants the necessary growth stimulus to become more resilient to the harsh conditions found on many mine reclamation sites.

Chromium (Cr) is a biologically non-essential, carcinogenic and toxic heavy metal. The cultivation of Cr-tolerant genotypes seems the most favorable and environment friendly strategy for rehabilitation and remediation of Cr-contaminated soils. To prove this hypothesis and identify the Cr tolerance, the present study was performed to assess the physiological and biochemical response of sunflower genotypes to Cr stress. The seeds of six sunflower hybrids, namely FH-425, FH-600, FH-612, FH-614, FH-619, and FH-620, were grown in spiked soil for 12 weeks under increasing concentrations of Cr (0, 5, 10, and 20 mg kg⁻¹). A seed germination test was also run under different concentrations of Cr (0, 5, 10, 200 mM) in petri dishes. Plants were harvested after 12 weeks of germination. Different plant attributes such as growth; biomass; photosynthesis; gas exchange; activity of antioxidant enzymes, i.e., superoxide dismutase (SOD), guaiacol peroxidase (POD), ascorbate (APX), and catalases (CAT); reactive oxygen species (ROS); lipid peroxidation; electrolyte leakage; and Cr concentration as well as accumulations in all plant parts were studied for the selection of the most Cr-tolerant genotype. Increasing concentration of Cr in soil triggered the reduction of all plant parameters in sunflower. Cr stress increased electrolyte leakage and production of reactive oxygen species which stimulated the activities of antioxidant enzymes and gas exchange attributes of sunflower. Chromium accumulation in the root and shoot increased gradually with increasing Cr treatments and caused reduction in overall plant growth. The accumulation of Cr was recorded in the order of FH-614 > FH-620 > FH-600 > FH-619 > FH-612 > FH-425. The differential uptake and accumulation of Cr by sunflower hybrids may be useful in selection and breeding for Cr-tolerant genotypes.

Sealing layers made of two alkaline paper mill by-products, fly ash and green liquor dregs, were placed on top of 50-year-old sulfide-containing tailings as a full-scale remediation approach. The performance and effectiveness of the sealing layers with high water content for an oxygen barrier and low hydraulic conductivity for a sealing layer in preventing the formation of acid rock drainage were evaluated 5 years after the remediation. The leaching behavior of the covered tailings was studied using batch leaching tests (L/S ratio 10 L/kg). The leaching results revealed that, in general, the dregs- and ash-covered tailings released relatively lower concentrations of many elements contained in acid rock drainage compared to those from the uncovered tailings. A change in the chemical composition and mineralogical state of the tailings was observed for the tailings beneath the covers. The increase in pH caused by the alkaline materials promoted metal precipitation. Geochemical modeling using PHREEQC confirmed most of the geochemical changes of the covered tailings. Both the ash and dregs showed potential to function as sealing materials in terms of their geochemical properties. However, mobilization of Zn and Ni from the lower part of the dregs-covered tailings was observed. The same phenomenon was observed for the lower part of the ash-covered tailings. Ash showed advantages over dregs as a cover material; based on geochemical studies, the ash immobilized more elements than the dregs did. Lysimeters were installed below the sealing layers, and infiltrating water chemistry and hydrology were studied to monitor the amount and quality of the leachate percolating through.

Apart from numerous other well-known drawbacks of chlorination, viz. on-site operational hazards and residual chlorine toxicity, trihalomethane (THM) formation is the major factor that came into limelight in the last 40 years, primarily in drinking water treatment industry. Treated effluent from wastewater treatment plants is also chlorinated and then discharged, indirectly coming in human contact, so there is need to consider THM as a potable as well as wastewater parameter. In this study, THMs were identified in seven sewage treatment plants (STPs) in North India. STPs were selected based on treatment technology employed, viz., up-flow anaerobic sludge blanket (UASB), activated sludge process (ASP), sequential batch reactor (SBR), and oxidation pond (OP). THM concentrations obtained at all the seven STPs were below BIS standards of drinking water (0–40 μg L⁻¹). UASB plant shows considerably higher concentration of THM. UV followed by chlorination is suggested as an alternative to chlorination. Per million liter per day (MLD) capital and operation and maintenance (O&M) costs of UV disinfection were analyzed revealing decreasing per MLD capital cost of UV with increasing plant capacity. The comparative annual O&M cost analysis of chlorination, dechlorination, and UV disinfection shows that there is up to 63% reduction of the total annual O&M cost by UV in comparison to chlorination, whereas in the case of chlorination followed by dechlorination, total reduction is 71%.

Bivalve species may be susceptible to environmental estrogenic compounds including estradiol (E₂). However, they are able to biotransform the hormone quite readily and inactivate its estrogenic action. To study the long-term effects of elevated free E₂ tissue levels, we transiently exceeded the biotransformation capacity of the clam Ruditapes decussatus by exposing them with high E₂ concentrations (400 ng/L) and subsequently study the consequences on gametogenesis during the following reproductive cycle. Exposure to 400 ngE₂/L led to a significant increase in tissue free E₂ levels, which reached 10–50 ng E₂Eq/gww. No deleterious effect on gonado-somatic index (GSI), condition index (CI), or ability to respond to the stress on stress test could be detected after a month of exposure, suggesting the absence of negative effects on the clam’s health. However, a marked increase in gametogenesis could be observed in both sexes during the exposure. Subsequent transplantation of the clams in the field allowed the normal development of the male clams and maturation of the gonads without any detrimental effect observed after 4 months. In contrast, in early July, all female clams formerly exposed to E₂ showed lower health status, and only ovaries with atretic oocytes while all control and indigenous females were normal and mature. These results show a sex-specific effect of high E₂ exposure and suggest either a direct or indirect role for E₂ in R. decussatus’ reproduction.

Plants integrate and monitor low temperature signals to cope with the continual variations in their environment. Arabidopsis thaliana cold responsive-element binding factor 3 (AtCBF3) plays its role in various cellular activities by modulating multiple genes induced under chilling stress. In this work, AtCBF3 transcription was remarkably induced following chilling stress. AtCBF3-overexpressors namely AtCBF3-Rio Grande, AtCBF3-Moneymaker, and AtCBF3-Roma showed defensible response to various levels of chilling stress, while their isogenic wild type plants indicated hypersensitive response to chilling stress. Detailed photosynthetic studies revealed that AtCBF3 gene has harmonious influences on the expression of a large set of genes by virtue of improved stomatal conductance, transpiration rate, intercellular CO₂ concentration, and photosynthetic rate compared to wild type plants. The AtCBF3 lines limited the water status-mediated hypersensitive response by lowering leaf osmotic potential due to overexpression of AtCBF3 under chilling stress. Biochemical analyses followed by phenotypic studies demonstrated that AtCBF3 plants exhibited membrane stability and lush green appearance by limiting membrane ions leakage and malondialdehyde contents and by accumulating more proline, soluble sugars, chlorophyll contents, carotenoid contents, and antioxidant enzymes relative to wild type plants. Hence, with a several lines of evidence, these findings support that tomato transgenic plants overexpressing Arabidopsis CBF3 show enhanced chilling tolerance.