Potatoes grown in soil with high Cd concentrations can accumulate high levels of Cd in the tubers. Although there is significant environmental variation involved in the trait of crop uptake of Cd, there are also distinctive cultivar differences. In order to understand this differential Cd accumulation mechanism, two potato cultivars were chosen that accumulate high and low levels of Cd in tubers. The patterns of Cd concentration, Cd content and dry weight accumulation of the two cultivars were examined at different stages of plant growth. The data suggest that differences in total Cd uptake and in Cd partitioning among organs are the mechanisms governing differential Cd-tuber accumulation in the two cultivars. The low tuber-Cd accumulator exhibited lower root-to-shoot and shoot-to-tuber translocation driven by higher root and shoot biomass that retained more Cd in roots and shoots, respectively, reducing its movement to the tubers. Higher remobilization and more efficient tuber loading was observed in the high tuber-Cd accumulator, indicating that remobilization of Cd from leaves to tubers was a major factor, not only in tuber-Cd loading, but also in the establishment of differential tuber-Cd levels. Regardless of cultivar differences, the concentration of Cd in the tuber was very low compared to that in other organs suggesting that, despite its high phloem mobility, Cd tends to be sequestered in the shoots.

Metals are among the most common environmental pollutants, and their presence in high concentration in waters and biota have devastating effects on flora, fauna, and human health. Flocculation process of metals during estuarine mixing can reduce the environmental hazards of metals and also can provide micronutrients to the aquatic system. The present investigation provides a thorough study of eliminating colloidal elements of copper, manganese, nickel, lead, and zinc during estuarine mixing of Shalmanrood River water with Caspian Sea water in Iran. The processes of flocculation were carried out in six different salinity regimes (0.45–2.4 ppt). The obtained result is indicative of non-conservative behavior of the studied metals. Higher flocculation resulted in a lower salinity regime. The obtained results indicated that most of the metals were eliminated during the initial mixing of fresh water with sea water at 0.45–0.9 ppt salinity interval. The trend of flocculation rates of elements is as follows: Zn (59.3%) > Pb (47.6%) > Mn (37.5%) > Cu (29.2%) > Ni (27%).The annual average load of copper (Cu), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn) from Shalmanrood River to Caspian Sea decreases as a result of flocculation process from 9.9, 7.7, 8.9, 5.1, and 23.2 tons per year to 7, 4.8, 6.5, 2.7, and 9.4 tons per year, respectively. According to the cluster analysis, parameters such as temperature, pH, and Eh do not have any impact on flocculation of elements expect for Pb. The only parameter that influences the flocculation of Mn is the salinity. Metal speciation studies that are carried out by Eh-pH software show that the studied metals are present as oxides (Zn, Cu, and Ni) and hydroxides (Mn and Pb).

Plants, being recognized to show high sensitivity to air pollution, have been long used to assess the ecological effects of airborne contaminants. However, many changes in vegetation are now generally attributed to atmospheric deposition of aerosol particles; the dose–effect relationships of this process are usually poorly known. In contrast to bioindication studies, ecotoxicological tests (or bioassays) are controlled and reproducible where ecological responses are determined quantitatively. In our study, the No. 227 OECD Guideline for the Testing of Chemicals: Terrestrial Plant Test: Vegetative Vigour Test (hereinafter referred to as ‘Guideline’) was adapted and its applicability for assessing the ecotoxicity of water-soluble aerosol compounds of aerosol samples was evaluated. In the aqueous extract of the sample, concentration of metals, benzenes, aliphatic hydrocarbons and PAHs was determined analytically. Cucumis sativus L. plants were sprayed with the aqueous extract of urban aerosol samples collected in a winter sampling campaign in Budapest. After the termination of the test, on day 22, the following endpoints were measured: fresh weight, shoot length and visible symptoms. The higher concentrations applied caused leaf necrosis due to toxic compounds found in the extract. On the other hand, the extract elucidated stimulatory effect at low concentration on both fresh weight and shoot length. The test protocol, based on the Guideline, seems sensitive enough to assess the phytotoxicity of aqueous extract of aerosol and to establish clear cause–effect relationship.

Coal-based thermal power plants are the major source of power generation in India. Combustion of coal gives rise to by-products such as fly ash (FA) in huge quantities. The current study focuses on physico-chemical and mineralogical characterization and risk evaluation of FA, generated from five thermal power plants (TPPs) of India. The coal, and corresponding FA and bottom ash (BA) were further analyzed for trace elements in order to observe the enrichment and partitioning behavior of elements. The environmental risk assessment of trace elements in FA was performed in accordance with geoaccumulation index (I gₑₒ) and potential ecological risk index (PERI). The results demonstrated that FA was enriched predominantly in SiO₂, Al₂O₃, and Fe₂O₃ along with small concentrations of CaO and MgO. The mineral phases identified in FA were quartz, mullite, hematite, and magnetite. Elemental characterization indicated that the metals were more enriched in FA as compared to coal and BA. The concentrations of trace elements, Cr, Pb, Hg, and As in FA (TPPs), varied from 12.59–24.28, 22.68–43.19, <0.0001–2.29, and 0.08–3.39 mg/kg, respectively. Maximum enrichment ratio (ER) was observed for Pb (5.21) in TPP3 FA. Hg in TPP1 showed the highest partition ratio (PR) value. I gₑₒ values for metals were mostly below zero. The PERI values indicated moderate risk from TPP4 FA and low risk from TPP1, TPP2, TPP3, and TPP5 FA to the environment, according to the threshold values provided.

To assess the different sensitivity to ozone (O₃) between transgenic Bt Shanyou63 (Bt-SY63) and its nontransgenic counterpart Shanyou63 (SY63), the leaf gas exchange, yield, grain elements, and antioxidant enzymes were investigated by performing a pot experiment under ambient O₃ concentration (A-O₃) and elevated O₃ concentration (1.5 × A-O₃, E-O₃). Under A-O₃, the chlorophyll content and yield of Bt-SY63 were significantly lower than those of SY63, whereas the stomatal conductance (Gs), cellular CO₂ concentration (Ci), and Fe, Zn concentration showed the opposite trends. No significant difference was detected for malondialdehyde (MDA) content between two cultivars, although the antioxidant enzymes including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities in Bt-SY63 tended to be higher than those in SY63. Exposure to E-O₃ resulted in significant reduction for photosynthesis (Pn), yield and all grain elements (except for N) concentration in both varieties, and the extents in Bt-SY63 were much greater than those in SY63. Meanwhile, significant increases for MDA content by 30.6 and 23.7% in Bt-SY63 and SY63, respectively, were detected under E-O₃. These results demonstrated that insertion of exogenous gene could induce several unintentional changes of Bt-SY63 in physiology and growth progress, compared with SY63 under ambient O₃ concentration. On the other hand, the injury of Bt-SY63 caused by elevated O₃ concentration was more severe than that of SY63. This study provided valuable baseline information for the commercial release and breeding strategies of Bt-SY63 under the projected future climate.

Copper mining has polluted soils and water, causing a reduction of the microbial diversity and a change in the structure of the resident bacterial communities. In this work, selective isolation combined with MALDI-TOF MS and the 16S rDNA method were used for characterizing cultivable bacterial communities from copper mining samples. The results revealed that MALDI-TOF MS analysis can be considered a reliable and fast tool for identifying copper-resistant bacteria from environmental samples at the genera level. Even though some results were ambiguous, accuracy can be improved by enhancing reference databases. Therefore, mass spectra analysis provides a reliable method to facilitate monitoring of the microbiota from copper-polluted sites. The understanding of the microbial community diversity in copper-contaminated sites can be helpful to understand the impact of the metal on the microbiome and to design bioremediation processes.

Plant invasion has been reported to affect a mass of soil ecological processes and functions, although invasion effects are often context-, species- and ecosystem- specific. This study was conducted to explore potential impacts of Praxelis clematidea invasion on contents of total and available soil nitrogen (N) and microbial N transformations in a tropical savanna. Soil samples were collected from the surface and sub-surface layers in plots with non-, slight, or severe P. clematidea invasion in Hainan Province of southern China, which remains less studied, and analyzed for contents of the total and available N fractions and microbial N transformations. Results showed that total N content significantly increased in the surface soil but trended to decrease in the sub-surface soil in the invaded plots relative to the non-invaded control. Slight invasion significantly increased soil alkali-hydrolysable N content in the two soil layers. Soil net N mineralization rate was not significantly changed in both the soil layers, although soil microbial biomass N was significantly higher in plots with severe invasion than the control. There was no significant difference in content of soil N fractions between plots with slight and severe invasion. Our results suggest that invasion of P. clematidea promotes soil N accumulation in the surface soil layer, which is associated with increased microbial biomass N. However, the invasion-induced ecological impacts did not increase with further invasion. Significantly higher microbial biomass N was maintained in plots with severe invasion, implying that severe P. clematidea invasion may accelerate nutrient cycling in invaded ecosystems.

The removal and recovery of phosphate from water by calcium-silicate composite (CSC) and alkali-treated calcium-silicate composite (ASC) was investigated. ASC had a higher specific surface area and total pore volume, and exhibited better performance of phosphate adsorption than CSC. In the batch mode adsorption studies, the isotherm adsorption experiments data fitted well the Langmuir isotherm model and the maximum adsorption capacities were 120 and 73.0 mg/g for ASC and for CSC, respectively. For the kinetic study, the experimental data fitted very well the pseudo-second-order kinetic model. The uptake of phosphate could be performed well over a wide pH range, from 3.0 to 13.0 for ASC and from 4.0 to 13.0 for CSC. The adsorption of phosphate by ASC was very selective even with 10 times higher concentration of other coexistent anions. For the adsorption of low phosphate concentration (10 mg/L), ASC could efficiently remove phosphate at the dosage of 0.8 g/L, while CSC was even difficult to remove phosphate at the dosage of 4.0 g/L. Phosphate fractionation results and FTIR spectra showed that phosphate-Ca complex was formed through phosphate adsorption process. The adsorbed phosphate could be successfully desorbed by 2% citric acid solution, indicating that the adsorbent after adsorbed phosphate could be reusable as fertilizer in the agricultural field.

The distribution of heavy metals in agricultural soils is affected by various anthropogenic activities and environmental factors occurring at different spatial scales. This paper introduced the two-dimensional empirical mode decomposition (2D-EMD) to separate the spatial variability in soil heavy metals into different scales. Geostatistics and multivariate analysis were also utilized to quantify their spatial structure and identify their potential influencing factors. The study was conducted in an arable land in southeastern China where 260 surface soil samples were collected and measured for total contents of cadmium (Cdₜₒₜₐₗ), mercury (Hgₜₒₜₐₗ), and sulfur (TS); pH; and soil organic carbon content (SOC). The results showed that both Cdₜₒₜₐₗ and Hgₜₒₜₐₗ had high coefficients of variation. The overall variation in all five soil variables was separated into three intrinsic mode functions (IMFs) and spatial residues. All three IMFs had short-range spatial correlations (1–8 km), while the spatial residues had moderate–large spatial ranges (13–39 km). IMF1 of Cdₜₒₜₐₗ was strongly correlated with IMF1 of SOC and TS, which was consistent with the principal component analysis. This indicated that IMF1 of Cdₜₒₜₐₗ represented local variations which were influenced by agricultural activities. IMFs of Hgₜₒₜₐₗ showed clustered distributions in the study area, with IMF1 and IMF2 of Hgₜₒₜₐₗ correlated in one principal component, and IMF3 of Hgₜₒₜₐₗ and IMF3 of soil pH in another component. This indicated that all three IMFs of Hgₜₒₜₐₗ might be influenced by different industrial activities or different pathways of the same industrial activities. The residues of Cdₜₒₜₐₗ and Hgₜₒₜₐₗ, representing the regional trends, only accounted for 26% of the total variance, whereas IMF1 contributed about half of the total variance. It can be concluded that agricultural activities and industrial activities were the dominant contributors of the overall variations in Cdₜₒₜₐₗ and Hgₜₒₜₐₗ in the study area, respectively.

Anode chamber of a dual chamber microbial fuel cell (MFC) having raw landfill leachate was inoculated with consortium of sulphate-reducing bacteria (SRB) and sulphide-oxidizing bacteria (SOB) to study the phylogenetic architecture, function and mutualism of anolyte community developed in the reactor. Enriched microbial community was analysed with the help of Illumina MiSeq and indicated the dominance of Firmicutes (41.4%), Clostridia (36.4%) and Clostridium (12.9%) at phylum, class and genus level, respectively. Clostridium was associated with fermentation as well as transfer of electrons to the electrode mediated by ferredoxin. Desulfovibrio (6.7%), Aeromonas (6.6%) and Tetrathiobacter (9.8%) were SRB-SOB associated with direct electron transfer to the electrode. Community analysis disclosed a syntrophic association among novel Firmicutes and Proteobacteria species for bioelectricity generation and degradation of organic matter. Complete removal of chemical oxygen demand was observed from landfill leachate within 3 days of inoculation. Lower oxidative slope and polarization resistance revealed from Tafel analysis backed the feasibility of electron transfer from microbes to anodic electrode and thus development of efficient anode-respiring community. Following enrichment and stabilization of the anodic community, maximum power density achieved was 9.15 W/m³ and volumetric current density was 16.17 A/m³. Simultaneous feeding with SRB-SOB and landfill leachate led to the enrichment of a novel, mutually interdependent microbial community capable of synchronized bioremediation of effluents rich in carbon, sulphate, nitrate and aromatic compounds.