Human activities lead to increasing concentration of the stable elements cesium (Cs) and strontium (Sr) and their radioactive isotopes in the food chain, where plants play an important part. Here we investigated Plantago major under the influence of long-term exposure to stable Cs and Sr.The plants were cultivated hydroponically in different concentrations of cesium sulfate (between 0.002 and 20 mM) and strontium nitrate (between 0.001 and 100 mM).Uptake of Cs and Sr into leaves was analyzed from extracts by inductively coupled plasma mass spectrometry (ICP-MS). It was increased with increasing external Cs and Sr concentrations. However, the efficiency of Cs and Sr transfer from solution to plants was higher for low external concentrations. Highest transfer factors were 6.78 for Cs and 71.13 for Sr. Accumulation of Sr was accompanied by a slight decrease of potassium (K) and calcium (Ca) in leaves, whereas the presence of Cs in the medium affected only uptake of K.The toxic effects of Cs and Sr were estimated from photosynthetic reactions and plant growth.In leaves, Cs and Sr affected the chlorophyll fluorescence even at their low concentrations. Low and high concentrations of both ions reduced dry weight and length of roots and leaves.The distribution of the elements between the different tissues of leaves and roots was investigated using Energy Dispersive X-Ray microanalysis (EDX) with scanning electron microscope (SEM). Overall, observations suggested differential patterns in accumulating Cs and Sr within the roots and leaves.When present in higher concentrations the amount of Cs and Sr transferred from environment to plants was sufficient to affect some physiological processes. The experimental model showed a potential for P. major to study the influence of radioactive contaminants and their removal from hotspots.

Radioactive contamination of the natural areas is one of the most long-lasting anthropogenic impacts on the environment. Scots pine (Pinus sylvestris L.) is a promising organism for radiation-related research because of its high radiosensitivity, but the genome size of Pinacea species has imposed obstacles for high-throughput studies so far. In this work, we conducted the analysis of the de novo assembled transcriptome of Scots pine populations growing in the Chernobyl-affected zone, which is still today contaminated with radionuclides because of the accident at the nuclear power plant in 1986. The transcriptome profiles indicate a clear pattern of adaptive stress response, which seems to be dose-dependent. The transcriptional response indicates a continuous modulation of the cellular redox system, enhanced expression of chaperones and histones, along with the control of ions balance. Interestingly, the activity of transposable element families is inversely correlated to the exposure levels to radiation. These adaptive responses, which are triggered by radiation doses 30 times lower than the one accepted as a safe for biota species by international regulations, suggest that the environmental management in radiation protection should be reviewed.

Waste water of the Kettara village, as well as the abandoned tailings, constitute a potential environmental issue with direct consequences on air, soil, water resources qualities and, on human health. In this paper, experimental investigations examine the environmental impact which is induced by the wastewater, mine tailings and the lithological factors of rocks. This multidisciplinary research allows to i) understand the transfer of the Metallic Trace Elements (selenium, arsenic, nickel and zinc) and sulfate ions in the fractured shales media, ii) to assess the water potability by using the microbiological analysis. The microbiological results reveal the domestic impact by the presence of several kinds of bacteria in the groundwater resources: E. coli, Fecal coliforms, Total coliforms, Enterococci, Mesophilic Aerobic Flora, Sulphite-reducing bacteria and Salmonella.Selenium, arsenic and the bacteriological contamination of the groundwater could be explained by five kinds of factors: i) the geological formations and the nature of the hydrogeological system (unconfined layer), ii) the groundwater flow, the hydraulic relation between the hydrogeological wells and, the fractures network in the shale aquifer. The piezometric map allows to highlight the groundwater flow from the North-East to North-West and to the South-West, the drainage axis towards the P21 well and the presence of the dividing axis in the contaminated zone by the arsenic, iii) the absence of the unhealthy habitats with permeable traditional septic tanks in the village; iv) the transfer of the spreading animal excrements from the soil to groundwater and, v) the migration of the wastewater towards downstream of the groundwater flow. The presence of the reed beds could explain the reduction of bacteria in the hydrogeological wells of the study area.

An influx of chloride ions from road de-icing solutions can result in toxicological effects to organisms in terrestrial and aquatic environments. As such, “eco-friendly” de-icing alternatives are sought to mitigate environmental impacts of de-icing impervious surfaces, while maintaining human safety. While many alternative de-icers are economically impractical for municipal use, the residential commercial market is flooded with de-icing formulations claiming to be “eco-friendly”. Given the little regulation and guidance that surrounds eco-labeling, the meaning of “eco-friendly” remains unclear in the context of biological systems. The objective of the current study was to determine the toxicity of three “eco-friendly” de-icing formulations to Chironomus dilutus using 10 d toxicity tests. The toxicity of these three formulations was compared to a traditional formulation composed entirely of chloride salts. Two of the “eco-friendly” de-icers demonstrated LC₅₀s of 6.61 and 6.32 g/L, which were similar in toxicity to the traditional sodium chloride formulation with a LC₅₀ 6.29 g/L. The comparable toxicities of these formulations is likely due to the presence of chloride salts in each of the “eco-friendly” de-icers. The third “eco-friendly” formulation, a urea-based de-icer, demonstrated toxicity an order of magnitude higher than that of the traditional formulation with an LC₅₀ of 0.63 g/L. While C. dilutus may not have been the intended endpoint in consideration when marketing these products as “eco-friendly”, consideration of how eco-labeling is utilized and the role of environmental scientists in determining the meaning of such claims must be considered to ensure continued and future protection of the environment.

Silver ions are among the predominant anthropogenic introduced pollutants in aquatic systems. As silver has effects on species at all trophic levels the community composition in aquatic habitats can be changed as a result of silver stress. The response of planktonic protists to environmental stressors is particularly important as they act both as producers and consumers in complex planktonic communities. Chrysomonad flagellates are of major interest, since this group includes heterotrophic, mixotrophic and phototrophic taxa, and therefore allows analysis of silver stress in organisms with contrasting nutritional strategies independent of a potential taxonomic bias. In a series of lab experiments, we compared the response of different trophic chrysophyte strains to low (5 μg L⁻¹), medium (10 μg L⁻¹) and high (20 μg L⁻¹) nominal Ag concentrations in combination with changes in temperature and light intensity (phototrophs), temperature and food concentration (heterotrophs), or a combination of the above settings (mixotrophs). All tested strains were negatively affected by silver in their growth rates. The phototrophic strains reacted strongly to silver stress, whereas light intensity and temperature had only minor effects on growth rates. For heterotrophic strains, high food concentration toned down the effect of silver, whereas temperatures outside the growth optimum had a combined stress effect. The mixotrophic strains reacted differently depending on whether their nutritional mode was dominated by heterotrophy or by phototrophy. The precise response pattern across all variables was uniquely different for every single species we tested. The present work contributes to a deeper understanding of the effects of environmental stressors on complex planktonic communities. It indicates that silver will negatively impact planktonic communities and may create shifts in their composition and functioning.

Dust samples were collected from four indoor environments, including childcare facilities, houses, hair salons, and a research facility from the USA and were analyzed for brominated compounds using full scan liquid chromatography high-resolution mass spectrometry. A total of 240 brominated compounds were detected in these dust samples, and elemental formulas were predicted for 120 more abundant ions. In addition to commonly detected brominated flame retardants (BFRs), nitrogen-containing brominated azo dyes (BADs) were among the most frequently detected and abundant. Specifically, greater abundances of BADs were detected in indoor dusts from daycares and salons compared to houses and the research facility. Using authentic standards, a quantitative method was established for two BADs (DB373: Disperse Blue 373 and DV93: Disperse Violet 93) and 2-bromo-4,6-dinitroaniline, a commonly used precursor in azo dye production, in indoor dust. Generally, greater concentrations of DB373 (≤3850 ng/g) and DV93 (≤1190 ng/g) were observed in indoor dust from daycares highlighting children as a susceptible population to potential health risk from exposure to BADs. These data are important because, to date, targeted analysis of brominated compounds in indoor environments has focused mainly on BFRs and appears to underestimate the total amount of brominated compounds.

The ultra-high Cd polluted environment is a special habitat in nature. Analysis of the biological adaptation and resistance mechanism of Auxenochlorella protothecoides UTEX234 to ultra-high Cd stress would offer some inspiring understanding on Cd detoxification mechanism and help discovering highly active bioremediation agents. In this study, integrated analyses of the transcriptome, multi-physiological and biochemical data and fatty acid profilings of UTEX2341 were performed for the first time. It was found that exogenous Ca ions could alleviate Cd stress. Manganese-dependent superoxide dismutase and peroxidase also participated in intracellular detoxification. And non-enzymatic antioxidants rather than one specific enzymatic antioxidant were suggested to be used as “core antioxidants”, which witnessed better performance in Cd detoxification. In addition, Cd stress improved sixteen alkane value and biofuel yield and quality.

Water availability is paramount in the response of soil invertebrates towards stress situations. This study aimed to evaluate the effects of forecasted soil moisture scenarios on the avoidance behavior of two invertebrate species (the arthropod Folsomia candida and the soft-bodied oligochaete Enchytraeus crypticus) in soils degraded by different types of anthropogenic metal(loid) contamination (mining soil and agricultural soil affected by industrial chemical wastes). Different soil moisture contents (expressed as % of the soil water holding capacity, WHC) were evaluated: 50% (standard soil moisture conditions for soil invertebrates' tests); 75% (to simulate increasing soil water availability after intense rainfalls and/or floods); 40%, 30%, 25% and 20% (to simulate decreasing soil water availability during droughts). Invertebrates’ avoidance behavior and changes in soil porewater major ions and metal(loid)s were assessed after 48 h exposure. Soil incubations induced a general solubilization/mobilization of porewater major ions, while higher soil acidity favored the solubilization/mobilization of porewater metal(loid)s, especially at 75% WHC. Folsomia candida preferred soils moistened at 50% WHC, regardless the soils were contaminated or not and the changing soil porewater characteristics. Enchytraeus crypticus avoided metal(loid) contamination, but this depended on the soil moisture conditions and the corresponding changes in porewater characteristics: enchytraeids lost their capacity to avoid contaminated soils under water stress situations (75% and 20–25% WHC), but also when contaminated soils had greater water availability than control soils. Therefore, forecasted soil moisture scenarios induced by global warming changed soil porewater composition and invertebrates capacity to avoid metal(loid)-contaminated soils.

High arsenic (As) concentrations in the soil, water and plant systems can pose a direct health risk to humans and ecosystems. Phosphate (Pi) ions strongly influence As availability in soil, its uptake and toxicity to plants. Better understanding of As(V)-Pi interactions in soils and plants will facilitate a potential remediation strategy for As contaminated soils, reducing As uptake by crop plants and toxicity to human populations via manipulation of soil Pi content. However, the As(V)-Pi interactions in soil-plant systems are complex, leading to contradictory findings among different studies. Therefore, this review investigates the role of soil type, soil properties, minerals, Pi levels in soil and plant, Pi transporters, mycorrhizal association and microbial activities on As-Pi interactions in soils and hydroponics, and uptake by plants, elucidate the key mechanisms, identify key knowledge gaps and recommend new research directions. Although Pi suppresses As uptake by plants in hydroponic systems, in soils it could either increase or decrease As availability and toxicity to plants depending on the soil types, properties and charge characteristics. In soil, As(V) availability is typically increased by the addition of Pi. At the root surface, the Pi transport system has high affinity for Pi over As(V). However, Pi concentration in plant influences the As transport from roots to shoots. Mycorrhizal association may reduce As uptake via a physiological shift to the mycorrhizal uptake pathway, which has a greater affinity for Pi over As(V) than the root epidermal uptake pathway.

Biodegradation of 1,4-dioxane was examined in packed quartz and soil column flow-through systems. The inhibitory effects of co-contaminants, specifically trichloroethene (TCE), 1,1-dichloroethene (1,1-DCE), and copper (Cu²⁺) ions, were investigated in the columns either with or without bioaugmentation with a 1,4-dioxane degrading bacterium Pseudonocardia dioxanivorans CB1190. Results indicate that CB1190 cells readily grew and colonized in the columns, leading to significant degradation of 1,4-dioxane under oxic conditions. Degradation of 1,4-dioxane was also observed in the native soil (without bioaugmentation), which had been previously subjected to enhanced reductive dechlorination treatment for co-contaminants TCE and 1,1-DCE. Bioaugmentation of the soil with CB1190 resulted in nearly complete degradation at influent concentrations of 3–10 mg L⁻¹ 1,4-dioxane and a residence reaction time of 40–80 h, but the presence of co-contaminants, 1,1-DCE and Cu²⁺ ions (up to 10 mg L⁻¹), partially inhibited 1,4-dioxane degradation in the untreated and bioaugmented soil columns. However, the inhibitory effects were much less severe in the column flow-through systems than those previously observed in planktonic cultures, which showed near complete inhibition at the same co-contaminant concentrations. These observations demonstrate a low susceptibility of soil microbes to the toxicity of 1,1-DCE and Cu²⁺ in packed soil flow-through systems, and thus have important implications for predicting biodegradation potential and developing sustainable, cost-effective technologies for in situ remediation of 1,4-dioxane contaminated soils and groundwater.