Suchergebnisse

The use of metal tolerant plants for the phytostabilization of metal contaminated soil is an area of extensive research and development. In this study the effects of inoculation of Ni-resistant bacterial strains on phytostabilization potential of various plants, including Brassica juncea, Luffa cylindrica and Sorghum halepense, were studied. A Ni-resistant bacterial strain SR28C was isolated from a nickel rich serpentine soil and identified as Bacillus megaterium based on the morphological features, biochemical characteristics and partial 16S rDNA sequence analysis. The strain SR28C tolerated concentrations up to 1200 mg Ni L 1 on a LuriaeBertani (LB) agar medium. Besides, it showed high degree of resistance to various metals (Cu, Zn, Cd, Pb and Cr) and antibiotics (ampicillin, tetracycline, streptomycin, chloramphenicol, penicillin and kanamycin) tested. In addition, the strain bound considerable amounts of Ni in their resting cells. Besides, the strain exhibited the plant growth promoting traits, such as solubilization of phosphate and production of indole-3-acetic acid (IAA) in modified Pikovskayas medium and LB medium, respectively in the absence and presence of Ni. Considering such potential, the effects of SR28C on the growth and Ni accumulation of B. juncea, L. cylindrica and S. halepense, were assessed with different concentrations of Ni in soil. Inoculation of SR28C stimulated the biomass of the test plants grown in both Ni contaminated and non-contaminated soils. Further, SR28C alleviated the detrimental effects of Ni by reducing its uptake and translocation to the plants. This study suggested that the PGPB inoculant due to its intrinsic abilities of growth promotion and attenuation of the toxic effects of Ni could be exploited for phytostabilization of Ni contaminated site. ; M. Rajkumar acknowledges the financial support received in the form of Ramalingaswami re-entry fellowship from Department of Biotechnology (DBT), Government of India. Y. Ma thankfully acknowledges the Portuguese Foundation for Science and Technology (FCT) for awarding a post-doctoral research grant (SFRH/BPD/ 76028/2011).

For many years, Beijing has suffered from severe air pollution. At present, fine particulate matter (PM2.5) pollution in the winter and ozone (O3) pollution in the summer constitute serious environmental problems. In this study, the combination of a comprehensive air quality model with particulate matter source apportionment technology (CAMx-PAST) and monitoring data was used for the high-spatial resolution source apportionment of secondary inorganic components (SNA: SO42−, NO3−, and NH4+) in PM2.5; their corresponding precursor gases (SO2, NO2, and NH3); and O3 in the winter and summer over Beijing. Emissions from residents, industry, traffic, agriculture, and power accounted for 54%, 25%, 14%, 5%, and 2% of PM2.5 in the winter, respectively. In the summer, the emissions from industry, traffic, residents, agriculture, and power accounted for 42%, 24%, 20%, 10%, and 4% of PM2.5, respectively. The monthly transport ratio of PM2.5 was 27% and 46% in the winter and summer, respectively. The regional transport of residential and industrial emissions accounted for the highest proportion of PM2.5. The regional transport of emissions had a significant effect on the SO42− and NO3− concentrations, whereas SO2 and NO2 pollution were mainly affected by local emissions, and NH4+ and NH3 were mainly attributed to agricultural emissions. Industrial and traffic sources were two major emission sectors that contributed to O3 pollution in Beijing. The monthly transport ratios of O3 were 31% and 65% in the winter and summer, respectively. The high-spatial resolution regional source apportionment results showed that emissions from Langfang, Baoding, and Tangshan had the greatest impact on Beijing's air pollution. This work's methods and results will provide scientific guidance to support the government in its decision-making processes to manage the PM2.5 and O3 pollution issues.

The aim of this study was to investigate the effects of metal mobilizing plant-growth beneficial bacterium Phyllobacterium myrsinacearum RC6b on plant growth and Cd, Zn and Pb uptake by Sedum plumbizincicola under laboratory conditions. Among a collection of metal-resistant bacteria, P. myrsinacearum RC6b was specifically chosen as a most favorable metal mobilizer based on its capability of mobilizing high concentrations of Cd, Zn and Pb in soils. P. myrsinacearum RC6b exhibited a high degree of resistance to Cd (350 mg L 1), Zn (1000 mg L 1) and Pb (1200 mg L 1). Furthermore, P. myrsinacearum RC6b showed multiple plant growth beneficial features including the production of 1-aminocyclopropane-1-carboxylic acid deaminase, indole-3-acetic acid, siderophore and solubilization of insoluble phosphate. Inoculation of P. myrsinacearum RC6b significantly increased S. plumbizincicola growth and organ metal concentrations except Pb, which concentration was lower in root and stem of inoculated plants. The results suggest that the metal mobilizing P. myrsinacearum RC6b could be used as an effective inoculant for the improvement of phytoremediation in multi-metal polluted soils. ; Y. Ma thankfully acknowledges the Portuguese Foundation for Science and Technology (FCT) for awarding a post-doctoral research grant (SFRH/BPD/76028/2011). M. Rajkumar acknowledges the financial support received in the form of Ramalingaswami re-entry fellowship from Department of Biotechnology (DBT), Government of India.

The research on municipal waste management is getting some traction from both scholars and practitioners. However, few studies have systematically reviewed this issue in China. Therefore, the purpose of our paper is to respond to this lacuna by systematically reviewing the research on urban waste management in China. In addition, we addressed the difficulties encountered by multiple stakeholders with respect to municipal waste management and provide a coherent understanding from a social governance perspective. Drawing on a systematic literature review, we analyzed 40 papers on social governance of waste management. The synthesis of previous studies demonstrates that although government deserves credit for guiding other actors, it cannot effectively safeguard the interests of all stakeholders. We integrated previous findings and gleaned suggestions for governments to implement strategic waste management.

AbstractEmployees' pro‐environmental behavior serves as a cornerstone in realizing organizations' sustainability initiatives. Leadership plays a vital role in shaping and nurturing the desired employee behaviors. Building upon social learning and self‐determination theories, we developed and tested a research model that investigated the mediating role of employees' green intrinsic motivation and the moderating influence of their green self‐efficacy on the relationship between green servant leadership and pro‐environmental behavior. Data were collected in two waves from 323 pairs of employee‐manager working in Pakistan's energy sector and analyzed with partial least squares path modeling (PLS‐PM). The findings endorsed that green servant leadership influences pro‐environmental behavior through the mediating mechanism of green intrinsic motivation. Further, green self‐efficacy played an interactive role with green servant leadership in shaping pro‐environmental behavior. This research responds to multiple calls for research and advances the knowledge on servant leadership and pro‐environmental behavior.

Abstract. In regions with distinct seasons, soil salinity usually
varies greatly by season. Thus, the seasonal dynamics of soil salinization
must be monitored to prevent and control soil salinity hazards and to reduce
ecological risk. This article took the Kenli District in the Yellow River
delta (YRD) of China as the experimental area. Based on Landsat data from
spring and autumn, improved vegetation indices (IVIs) were created and then
applied to inversion modeling of the soil salinity content (SSC) by
employing stepwise multiple linear regression, back propagation neural
network and support vector machine methods. Finally, the optimal SSC model
in each season was extracted, and the spatial distributions and seasonal
dynamics of SSC within a year were analyzed. The results indicated that the
SSC varied by season in the YRD, and the support vector machine method
offered the best SSC inversion models for the precision of the calibration
set (R2>0.72, RMSE < 6.34 g kg−1) and the validation
set (R2>0.71, RMSE < 6.00 g kg−1 and RPD > 1.66). The best SSC inversion model for spring could be applied to the SSC
inversion in winter (R2 of 0.66), and the best model for autumn could be applied to the SSC inversion in summer (R2 of 0.65). The SSC exhibited a gradual increasing trend from the southwest to northeast in the Kenli District. The SSC also underwent the following seasonal dynamics: soil salinity accumulated in spring, decreased in summer, increased in autumn and reached its peak at the end of winter. This work provides data support for the control of soil salinity hazards and utilization of saline–alkali soil in the YRD.