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Benzo[a]pyrene (B[a]P) as a representative polycyclic aromatic hydrocarbons is concerned by global scientists in various fields, but its biological and biochemical actions in soil-wheat systems are still rarely reported. The B[a]P as a ubiquitous soil pollutant possesses varied contents in real environment, and herein was studied in systems of soil and wheat to obtain relative results to reveal their variations in different systems. Its bioavailability (extractability and bioaccumulation) and basic biological toxicity were tested based on three typical soil types (red, black, and brown) in China and spiked amounts (0.1, 1, and 10 mg/kg) with several orders of magnitude. Results showed that B[a]P concentrations in soil-wheat systems extracted by HPCD were insignificantly (p > 0.05) higher than Tenax-TA, and varied with soil types and spiked concentrations. Besides, the root and shoot length were mostly inhibited, in a range of -21.85%-26.35% and -0.48%-54.85%, respectively, by B[a]P in different soil types and increased with its increasing concentration. Comparatively, higher bioconcentration factor and translocation factor values were observed under lower group in red soil-wheat systems, and higher spiked groups in black and brown soil-wheat systems. Moreover, inhibitive effects posed by B[a]P were mainly targeted at wheat shoots in these soils. The simultaneous studies provided a comparable knowledge of B[a]P in ecosystems of different soil types combined with different plant species due to lots of variations, further to serve for contaminated soil remediation and sustainable agricultural management.

Solid-state ionic conductors are compelling alternatives to liquid electrolytes in clean energy-harvesting and -storage technologies. The development of novel ionic conducting materials is one of the most critical challenges for next-generation energy technologies. Several advancements in design strategies, synthetic approaches, conducting properties, and underlying mechanisms for ionic conducting metal-organic frameworks (MOFs) have been made over the past five years; however, despite the recent, considerable expansion of related research fields, there remains a lack of systematic overviews. Here, an extensive introduction to ionic conducting performance for MOFs with different design strategies is provided, focusing primarily on ion mobility with the aid of hydrogen-bonding networks or solvated ionic charge. Furthermore, current theories on ion conducting mechanisms in different regimes are comprehensively summarized to provide an understanding of the underlying working principles in complex, realistic systems. Finally, challenges and future research directions at the forefront of ionic conducting MOF technologies are outlined.

During land development, some important changes take place in the soil environment. Understanding these responses is of great significance for solving local and global environmental issues caused during land development. Till now, studies within education parks or university/college towns, especially inside and outside of a campus, were rarely reported. Herein, treating a campus as a semi‐open and coupled system, we collected soil samples (109 sites) inside and outside of a campus to reveal the variation in their soil‐geochemical parameters, available microelements, and microbial communities. Results shown that soil samples inside of the campus had lower pH (p

Many countries have developed university/college towns with specific characteristics (temporal, spatial, structural, and functional aspects). During the land development, there were obvious changes in soil metal levels and distribution patterns attributed to anthropogenic activities, thus having induced comparable results in university/college towns due to similar anthropogenic activities. Until now, specific studies on the metal status in university/college towns, especially the variation inside and outside of a campus were rarely involved. Herin we report on 109 soil samples around a new campus within a developing education park, in which the levels, spatial distributions, and possible sources of (alkali, alkaline‐earth, transition, and main group) metals and metalloids (Cd, Cr, As, Pb, Zn, Cu, Mn, Ba, Ni, Ti, Be, Bi, Sb, Sn, Co, V, and Zr) were systematically investigated. The Nemerow pollution indexes, spatial analysis, principal components analysis, and cluster analysis were calculated and analyzed. The results showed that the level of most metals within the campus with different functional areas (college, activity, and greening areas) was 1–1.3‐times as much as that outside in four directions and had greater variations. Moreover, the level of most metals was 1–1.5‐times as much as their background value and they distributed in the areas under specific developments and might mainly be attributed to anthropogenic sources. These findings provide the knowledge about effects of land development and anthropogenic activities on soil metal status that could be used by university/college towns in the similar context around the world.

This work was financially supported by the National Natural Science Foundation of China (NSFC Nos. 21875112 and 21576139), the National and Local Joint Engineering Research Center of Biomedical Functional Materials, and the Priority Academic Program Development of Jiangsu Higher Education Institutions.

A review of the literature published in 2016 on topics relating to water reclamation and reuse is summarized. The review is divided into the following sections: 1) General: monitoring and assessment, social awareness and acceptance, and energy and resources recovery; 2) Treatment technology: integrated technologies, membrane treatment, reactors, WSPs, disinfection, and others; 3) Planning and Management: modeling, LCA, GHG emission, and case studies. Much of the water treatment research focused on the integrated technologies and membrane treatment.

Efficient noninvasive techniques are desired for repairing organic-contaminated soils. Bioelectrochemical technology, especially microbial fuel cells (MFCs), has been widely used to promote a polluted environmental remediation approach, and applications include wastewater, sludge, sediment, and soil remediation. Soil MFC remediation has been of significant concern in recent years, and thus, several aspects, including reactor configuration, electrode materials, soil conductivity, mass transfer, and microbial activity, are reviewed. Recent studies and key issues of soil MFCs and perspectives of organic-contamination remedial application are summarized, with the aim of assisting environmental scholars and engineers to gain a comprehensive understanding of MFC remediation. Insights are also offered on how to extend applications to help soil MFC remediation technology to advance and be applied in the future on a large scale.

To mitigate the impact and dissemination of clubroot in western Canada, canola (Brassica napus) producers have relied on clubroot resistance traits. However, in 2013 and 2014, new strains of the clubroot pathogen, Plasmodiophora brassicae, emerged that are virulent on most clubroot-resistant (CR) canola genotypes. Novel strains of the pathogen were inoculated onto two susceptible canola cultivars, one resistant line and six CR cultivars. Although all cultivars/lines showed a susceptible response to inoculation with the new strains of P. brassicae, the severity of disease reaction, root hair infection rates and the amount of P. brassicae DNA present in each canola genotype varied depending on the strain. In addition, the effect of inoculum density on disease severity and gall formation was recorded for one of these new strains on a universally susceptible Chinese cabbage cultivar and one susceptible and 10 resistant canola genotypes. Although root galls were observed at an inoculum density of 103 spores per mL of soil, clear differentiation of susceptible and resistant reactions among canola cultivars/lines was not observed until the inoculum density reached 105 spores mL−1. At a spore density of 106 spores mL−1 and above, all cultivars/lines developed susceptible reactions, although there was some differentiation in the degree of reaction. This study shows the potential to develop a unique disease profile for emergent clubroot pathotypes and shows a useful range of spore densities at which to study new P. brassicae strains.

BACKGROUND: Bioelectrochemical remediation of soils contaminated by petroleum hydrocarbons has received increasing attention as an effective approach to remove pollution with simultaneous electricity generation. RESULTS: Here, glucose was added as a co-substrate in this system. The charge output of soil microbial fuel cells (MFCs) was enhanced by 262%, and the total petroleum hydrocarbon degradation rate increased by 200%. According to the increased dehydrogenase and polyphenol oxidase activities, the exogenetic glucose substantially activated hydrocarbon degradation bacteria (such as Alcanivorax). The Shannon–Wiener Index and richness of soil microbial community decreased after glucose addition, indicating that a selective enrichment of specific communities was imposed by glucose. Correlation analysis showed the biodiversity in soil far from the cathode was mainly determined by the concentration of petroleum hydrocarbons, while that in soil close to the cathode was dominated by the current. CONCLUSION: This study demonstrated that an exogenetic carbon source enhanced the bioelectrochemically assisted degradation of aged petroleum hydrocarbons in saline soils, providing an effective approach to remove contaminations from soil in barren areas or extreme environments. © 2015 Society of Chemical Industry Supporting information may be found in the online version of this article.

Plasmodiophora brassicae, causal agent of clubroot of crucifers, poses a serious threat to Canadian canola production. The effects of fallow (F) periods and bait crops (clubroot-susceptible canola (B) and perennial ryegrass (R)) on clubroot severity and P. brassicae resting spore populations were evaluated in five sequences: R–B, B–R, R–F, B–F and F–F. Both host and non-host bait crops reduced clubroot severity in a subsequent crop of a susceptible canola cultivar compared with fallow. Resting spore and P. brassicae DNA concentrations decreased in all treatments, but were lowest for the R–B and B–R bait crop sequences. In addition, two studies were conducted in mini-plots under field conditions to assess the effect of rotation of susceptible or resistant canola cultivars on clubroot severity and P. brassicae resting spore populations. One study included three crops of susceptible canola compared with a 2-year break of oat–pea, barley–pea, wheat–wheat or fallow–fallow. The other study assessed three crops of resistant canola, two crops of resistant canola with a 1-year break, one crop of resistant canola and a 2-year break, and a 3-year break with barley followed by a susceptible canola. The rotations that included non-host crops of barley, pea or oat reduced clubroot severity and resting spore concentrations, and increased yield, compared with continuous cropping of either resistant or susceptible canola. Growing of a susceptible canola cultivar contributed 23–250-fold greater gall mass compared with resistant cultivars.

Clubroot, caused by Plasmodiophora brassicae, has become a serious threat to canola (Brassica napus) production in western Canada. Experiments were conducted under greenhouse and field conditions to assess the effect of Vapam fumigant (dithiocarbamate; sodium N-methyldithiocarbamate) on primary and secondary infection by P. brassicae, clubroot severity, and growth parameters in canola. Preliminary trials showed a 12–16-fold reduction in primary and secondary infection and clubroot severity at all of the Vapam application rates (0·4–1·6 mL L−1 soil) assessed. Vapam was also found to be effective in reducing clubroot severity and improving seed yield of canola under field conditions. Application of Vapam at soil moisture levels in the range of 10–30% (v:v) had a large effect on both disease severity and infection rates and plant growth parameters. The results suggest that Vapam can effectively reduce clubroot severity and may be useful for the treatment of transplant propagation beds in brassica vegetable production, and for the containment of small, localized clubroot infestations in commercial canola crops.

Bean anthracnose is a seedborne disease of common bean (Phaseolus vulgaris) caused by the fungal pathogen Colletotrichum lindemuthianum. Using seed that did not test positive for the pathogen has been proven to be an effective strategy for bean anthracnose control. To quantify the extent of anthracnose seed infection, a real-time PCR-based diagnostic assay was developed for detecting C. lindemuthianum in seeds of the commercial bean class navy bean. The ribosomal DNA (rDNA) region consisting of part of the18S rDNA, 5.8S rDNA, internal transcribed spacers (ITS) 1, 2 and part of the 28S rDNA of seven races of C. lindemuthianum, 21 isolates of Colletotrichum species and nine other bean pathogens were sequenced with the universal primer set ITS5/ITS4. Based on the aligned sequence matrix, one primer set and a probe were designed for a SYBR Green dye assay and a TaqMan MGB (minor groove binder) assay. The primer set was demonstrated to be specific for C. lindemuthianum and showed a high sensitivity for the target pathogen. The detection limit of both assays was 5 fg of C. lindemuthianum genomic DNA. To explore the correlation between the lesion area and the DNA amount of C. lindemuthianum in bean seed, seeds of the navy bean cultivar Navigator with lesions of different sizes, as well as symptomless seeds, were used in both real-time PCR assays.

BACKGROUND: Pt-free cathodic catalyst is needed for microbial fuel cells (MFCs). Perovskite-type oxide could be a substitute for Pt because it has been proved to be a highly active and low-cost oxygen reduction catalyst in chemical fuel cells. RESULTS: A nano-sized La0.4Ca0.6Co0.9Fe0.1O3 perovskite-type oxide on a carbon support (LCCF/C) was prepared and tested for its performance and stability (15 cycles) in MFCs. An exchange current density of 7.030 × 10−5 (A cm−2) was obtained with fresh LCCF/C cathode and is increased to 7.438 × 10−5 (A cm−2) after 15 cycles operating in MFCs. A power density of 405 mW m−2 was achieved with the LCCF/C cathode at the 2nd cycle which was between those of Pt/C (560 mW m−2) and C (339 mW m−2) cathodes. At the end of the 15th cycle, the lowest decay (due to biofouling) rate on the open circuit voltage (2%) and the maximum power density (15%) were observed with LCCF/C cathode compared with those of Pt/C (4%, 17%) and C (22%, 69%) cathodes, respectively. CONCLUSIONS: This study demonstrated that perovskite-type oxide on carbon support catalysts could be a potential substitute for Pt for cathodic oxygen reduction reaction (ORR) in air-cathode MFCs. © 2012 Society of Chemical Industry

Clubroot, caused by Plasmodiophora brassicae, has become a serious threat to canola (Brassica napus) production in western Canada. Experiments were conducted to assess the effect of growing resistant and susceptible canola genotypes on P. brassicae soil resting spore populations under greenhouse, mini-plot and field conditions. One crop of susceptible canola contributed 1·4 × 108 spores mL−1 soil in mini-plot experiments, and 1 × 1010 spores g−1 gall under field conditions. Repeated cropping of susceptible canola resulted in greater gall mass compared to resistant canola lines. It also resulted in reduced plant height, increased clubroot severity in susceptible canola, and increased numbers of resting spores in the soil mix.

The impact on clubroot severity of growing susceptible canola or mixtures of resistant and susceptible canola genotypes was examined. Bioassays revealed greater clubroot severity and incidence, and reduced plant height, where 100% of a susceptible cultivar had been grown. A higher proportion of susceptible plants within a resistant canola crop increased root hair and secondary infections. Regression analysis of root hair infection and the amount of Plasmodiophora brassicae DNA (as determined by quantitative PCR) revealed strong linear relationships between the two parameters. The linear relationships between root hair infection and P. brassicae DNA were stronger for the resistant cultivar than for the susceptible cultivar when regression analysis was conducted by cultivar over the sampling dates. In conclusion, the cropping of a resistant cultivar reduced clubroot severity, while the presence of susceptible volunteer canola increased inoculum potential. Quantitative PCR was a reliable tool for the quantification of root hair infection.

Summary Concern about combined pollution of agricultural ecosystems by chlorimuron-ethyl (CHL) and copper (Cu) has increased of late, particularly in northeastern China. Sorption and desorption of CHL and Cu on soils and their interactive effects strongly affect their mobility and bioavailability. Thus, the interaction between CHL and Cu(II) with regard to their sorption and desorption on brown earth (BE, luvisols) and black soils (BS, phaeozem), two typical soils in northeastern China, was investigated by using batch experiments. The results indicated that the presence of Cu(II) increased the sorption of CHL on the two soils, which can be attributed to decreased pH in the equilibrium solution and Cu-bridging. The formation of a Cu-CHL complex with stronger affinity to the soils than CHL itself may be another mechanism. Addition of Cu(II) also enhanced the hysteresis effect of CHL desorption from BS but decreased that from BE. CHL at small concentrations promoted Cu(II) slightly sorption on BE and BS by the bridging effect of CHL. In addition, CHL suppressed Cu(II) desorption from the two soils, decreasing the mobility and bioavailability of Cu(II).

The impact of cultivar resistance and inoculum density on the incidence of primary infection of canola root hairs by Plasmodiophora brassicae, the causal agent of clubroot, was assessed by microscopy. The incidence of root hair infection in both a resistant and a susceptible cultivar increased with increasing inoculum density, but was two- to threefold higher in the susceptible cultivar; the relationship between root hair infection and inoculum density was also substantially stronger and more consistent in the susceptible cultivar. In the susceptible cultivar, the root hair infection rate peaked between 6 and 8 days after sowing and then declined. In the resistant cultivar, it increased over the 14-day duration of each study. It appears that examination of root hair infection by microscopy in a bait crop of susceptible canola could serve as a useful tool for estimating P. brassicae inoculum levels in soil. In a separate trial, the relationship between inoculum density and clubroot severity, plant growth parameters, and seed yield was assessed under greenhouse conditions. Inoculum density in the susceptible genotype was strongly and positively correlated with clubroot severity and negatively correlated with plant height and seed yield. In addition, a single cropping cycle of the susceptible cultivar contributed significantly higher levels of resting spores to the soil in a greenhouse test than did a cycle of the resistant cultivar, as assessed by quantitative PCR and microscope analysis.

Polycyclic musks have been indicated to cause lethal and sublethal effects on exposed biota. However, knowledge about the effect of polycyclic musks on the antioxidant defense system in earthworms is vague. In this work, the activities of antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and malondialdehyde (MDA) exposed to 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethyl-cyclopenta-γ-2-benzopyran (HHCB) were systematically investigated. The investigation shows that their activities are closely related to the exposed dose and time of HHCB. For SOD and CAT, the activities increased monotonically with increased exposed dose of HHCB, which indicates a dose-dependent change pattern. POD exhibited its peak activity in 0.0157 μg cm(-2) HHCB treatment and decreased at higher concentrations. These two changing patterns were complementary, which reveals the cooperation of enzymes in response to oxidative stress. MDA content in earthworms was basically unaffected with a 1-day exposure and significantly increased after 2-day and 3-day exposures, correlating with changes in the activities of SOD and CAT when the concentration of HHCB was high. It was also found that the sensitivity of Eisenia fetida to HHCB increased over time. These results may support the theoretical hypothesis that oxidative stress is an important component for the response of earthworms to the toxicity of HHCB in environment. Among the studied enzymes, SOD and CAT appeared to be the most responsive biomarkers of oxidative stress caused by HHCB. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012.

The study focused on the proposal and experimental validation of an combined photoelectrocatalytic principle for chemical oxygen demand determination (combined PeCOD, PeCOD-combined), which was functionally comprised of photon-efficient thin-film photochemical, photocarrier-efficient electrochemical and conventional bulk-phase photochemical digestion types in one single photodigestion process. The combined PeCOD technology was proposed mainly on the basis of the significantly informative work of existing photoelectrocatalytic COD (thin-layer PeCOD, PeCOD-thin), and could realize the three different digestion types on one single rotating photoanode. The three important operation conditions of rotating speed, applied bias and pH value were investigated and optimized, and a wide analytical linear range of 2.7–11 500 mg/L was consequently obtained during an approximately 5–110 min determination period, and a real sample analysis further validated the practical feasibility of the proposed PeCOD-combined. In PeCOD-combined the main organics digestion and signal generation occurred via PeCOD-thin due to efficient UV utilization and excellent photodigestion activity.

The adsorption and desorption behavior of tetracycline on an Alfisol and an Ultisol was investigated at varying soil/solution ratios (1:10, 1:50, and 1:100) and different cation types (CaCl 2 , KCl, and NaCl) and H 2 O using a batch equilibration experiment. Kinetic studies revealed that the adsorption of tetracycline on the two soils was rate limited, and the adsorption kinetics could be well described by the Elovich equation and exponent equation. Changes in the soil/solution ratio affected the relative equilibration time in the Ultisol, but there was no effect of the initial tetracycline concentration. The adsorption rate in the soils decreased as the soil/solution ratio increased from 1:50 to 1:10. The adsorption and desorption data on tetracycline in the two soils could be described by the Freundlich isotherm equation, with r values >0.952 under all experimental treatments. The Ultisol always had stronger adsorption (higher distribution coefficient [K d ] value) than the Alfisol under all experimental conditions. The K d values decreased with increasing soil/solution ratios in the two tested soils at 1 or 1.25 mg L ―1 of tetracycline; however, this trend did not occur at 25 mg L ―1 of tetracycline. The adsorption isotherm had an S-type curve that changed into an L-type curve with decreasing soil/solution ratios from 1:10 to 1:100. The presence of cations in the soil solution, especially CaCl 2 , can significantly reduce the adsorption of tetracycline in soils. The presence of cations also significantly reduced the nonlinearity of the adsorption isotherms.

Clubroot, caused by Plasmodiophora brassicae, is one of the most serious diseases of cultivated cruciferous crops in the world. However, the basis for pathogenicity in P. brassicae is not well understood. In this study, a serine protease gene (PRO1) was cloned from P. brassicae and its molecular characteristics were investigated. Southern analysis and specific polymerase chain reaction (PCR) amplification indicated that PRO1 is a single-copy gene present in a broad range of P. brassicae pathotypes. Northern analysis revealed that the expression of PRO1 was induced during plant infection, and that the quantity of transcript fluctuated according to the stage of pathogenesis. Amino acid sequence analysis suggested that the encoded protein (Pro1) belongs to the S28 family of proteases, with a predicted signal peptide and a theoretical molecular mass of 49.4 kDa. The open reading frame (ORF) of PRO1 was transferred into Pichia pastoris and Pro1 was heterologously produced. Pro1 showed proteolytic activity on skimmed milk and N-succinyl-Ala-Ala-Phe-7-amido-4-methylcoumarin, and the activity could be inhibited by serine protease inhibitors and the chelating agent ethylenediaminetetraacetic acid. The optimal temperature of Pro1 was 25 degrees C, and it exhibited high activity at pH 6.0-6.4. These values coincide with the temperature and pH conditions favourable for P. brassicae resting spore germination in the field. When Pro1 was used to treat canola root exudates, it enhanced the stimulating effect of the root exudates on P. brassicae resting spore germination, indicating that Pro1 may play a role during clubroot pathogenesis by stimulating resting spore germination through its proteolytic activity.

Increasing attention is now being paid to antibiotic contamination as a serious environmental issue. Chlortetracycline has been widely used for decades as a human and veterinary medicine, which has resulted in environmental residues and damage to living organisms. In the present study, the physiological and potential genetic toxicity of chlortetracycline was investigated using a wheat (Triticum aestivum L.) bioassay at a concentration range of 0.0625 to 300 mg/L and an exposure time of 24, 48, and 72 h. The results indicated that chlortetracycline at the lower concentrations stimulated germination and cell mitotic division and growth, whereas higher concentrations significantly inhibited processes such as bud length (50–300 mg/L), percentage germination (25–300 mg/L), root length (25–300 mg/L), and mitotic index (MI) (25–300 mg/L). The lowest concentration of chlortetracycline slightly augmented the frequency of micronucleus (MN), chomosomal aberration (CA), and sister chomatid exchange (SCE) in the root tips; however, significant (p

Both oxidative stress and neurotoxicity are huge challenges to human health, and effective methods and agents for resisting these adverse effects are limited, especially in vivo. It is shown here that, compared to large graphene oxide (GO) nanosheets, GO quantum dots (GOQDs), as nanozymes, efficiently reduce reactive oxygen species (ROS) and H2O2 in 1‐methyl‐4‐phenyl‐pyridinium ion (MPP+)‐induced PC12 cells. In addition, GOQDs exert neuroprotective effects in a neuronal cell model by decreasing apoptosis and α‐synuclein. GOQDs also efficiently diminish ROS, apoptosis, and mitochondrial damage in zebrafish treated with MPP+. Furthermore, GOQDs‐pretreated zebrafish shows increased locomotive activity and Nissl bodies in the brain, confirming that GOQDs ameliorate MPP+‐induced neurotoxicity, in contrast to GO nanosheets. GOQDs contribute to neurotoxic amelioration by increasing amino acid metabolism, decreasing tricarboxylic acid cycle activity, and reducing steroid biosynthesis, fatty acid biosynthesis, and galactose metabolic pathway activity, which are related to antioxidation and neurotransmission. Meanwhile, H2O2 decomposition and Fenton reactions suggest the catalase‐like activity of GOQDs. GOQDs can translocate into zebrafish brains and exert catalase‐mimicking activity to resist oxidation in the intracellular environment. Unlike general nanomaterials, biocompatible GOQDs demonstrate their high potential for human health by reducing oxidative stress and inhibiting neurotoxicity.

The ecotoxicological effects of aluminum (Al)-based coagulants are of concern because of their wide-ranging applications in wastewater treatment and water purification. As important Al-based coagulants, AlCl3 and PAC (polyaluminum-chloride) were selected as examples to examine the toxic effects on representative vegetables including the cabbage Brassica chinensis and the radish Raphanus sativus over a range of exposure concentrations in neutral (pH 7.00) and acidic (pH 4.00) conditions, using seed germination and root elongation in the early-growth stage as indicators of toxicity. The results showed that root elongation of the two vegetables was a more sensitive indicator than was seed germination for evaluating the toxicity of Al. As a single influencing factor, H+ had no significant direct effects on root elongation of Brassica chinensis and Raphanus sativus under the experimental conditions. The toxicity of Al played the main role in inhibiting root elongation and seed germination and was strongly related to changes in pH. There was a markedly positive relationship between the inhibitory rate of root elongation, seed germination, and the concentration of Al at pH 4.00 (p < 0.01). The toxic effect of AlCl3 on Brassica chinensis was less with a neutral pH than at pH 4.00, but Raphanus sativus was more susceptible to AlCl3 toxicity at a neutral pH than at pH 4.00. Both Raphanus sativus and Brassica chinensis had a more toxic response to a low concentration (