Geochemical characteristics of inorganic sulfur in Shijing River, South China

Different inorganic sulfur species distributed in overlying water, pore water and sediment in a heavily polluted river were determined. The concentrations of S(2-) and SO(4)(2-) in the overlying water were much more than those in the pore water. This result perhaps indicates the S(2-) was mainly from discharged wastewater, not from sediment resuspension. In the sediments, acid-volatile sulfide, chromium(ii)-reducible sulfide, and elemental sulfur were determined by a modified diffusion method. The results indicate that acid-volatile sulfide was the dominant component of the reduced inorganic sulfur, making up about 62% of the total reduced inorganic sulfur.     

Effects of ambient temperature on regulated gaseous and particulate emissions from gasoline-, E10- and M15-fueled vehicles

• Emissions from two sedans were tested with gasoline, E10 and M15 at 30°C and -7°C. • As the temperature decreased, the PM, PN and BC emissions increased with all fuels. • Particulate emissions with E10 and M15 were more sensitive to the temperature. • The PN and BC generated during cold start-up dominated those over the WLTC. Ambient temperature has substantial impacts on vehicle emissions, but the impacts may differ between traditional and alcohol gasolines. The objective of this study was to investigate the effects of temperature on gaseous and particulate emissions with both traditional and alcohol gasoline. Regulated gaseous, particle mass (PM), particle number (PN) and black carbon (BC) emissions from typical passenger vehicles were separately quantified with gasoline, E10 (10% ethanol and 90% gasoline by volume) and M15 (15% methanol and 85% gasoline by volume) at both 30°C and -7°C. The particulate emissions with all fuels increased significantly with decreased temperature. The PM emissions with E10 were only 48.0%–50.7% of those with gasoline at 30°C but increased to 59.2%-79.4% at -7°C. The PM emissions with M15 were comparable to those with gasoline at 30°C, but at -7°C, the average PM emissions were higher than those with gasoline. The variation trend of PN emissions was similar to that of PM emissions with changes in the fuel and temperature. At 30°C, the BC emissions were lower with E10 and M15 than with gasoline in most cases, but E10 and M15 might emit more BC than gasoline at -7°C, especially M15. The results of the transient PN and BC emission rates show that particulate emissions were dominated mainly by those emitted during the cold-start moment. Overall, the particulate emissions with E10 and M15 were more easily affected by ambient temperature, and the advantages of E10 and M15 in controlling particulate emissions declined as the ambient temperature decreased.     

Changes of main secondary metabolites in leaves of Ginkgo biloba in response to ozone fumigation

To investigate the effect of elevated O3 on the accumulation of main secondary metabolites in leaves of Ginkgo biloba L., four-year-old trees were exposed in open-top chambers with ambient air and the air with twice ambient O3 concentration in Shenyang in 2006.Elevated O3 increased the concentrations of terpenes, but decreased the concentrations of phenolics in G.biloba leaves.The results showed that secondary compounds from G.biloba leaves responded to the elevated O3 exposure in a different way when compared to previous studies which showed elevated O3 increased the concentrations of phenolics but had no effect on the terpenes in leaves of other deciduous trees.Furthermore, reduced synthesis of phenolics may decrease the resistance of G.biloba to O3 and other environmental factors.On the other hand, the induced synthesis of terpenes may enhance the antioxidant abilities in G.biloba leaves at the end of O3 fumigation.     

Efficient conversion of lignin waste and self-assembly synthesis of C@MnCo2O4 for asymmetric supercapacitors with high energy density

Lignin waste from the papermaking and biorefineries industry is a significantly promising renewable resource to prepare advanced carbon materials for diverse applications,such as the electrodes of supercapacitors;however,the improvement of their energy density remains a challenge.Here,we design a green and universal approach to prepare the composite electrode material,which is composed of lignin-phenolformaldehyde resins derived hierarchical porous carbon (LR-HPC) as conductive skeletons and the...     

Effects of temperature parameters on thermal-optical analysis of organic and elemental carbon in aerosol

Thermal-optical analysis (TOA) is a popular method to determine aerosol elemental carbon (EC) and organic carbon (OC) collected on quartz fiber filter. However, temperature protocol adopted in TOA has great effects on OC and EC results. The purpose of this study is to investigate and quantify the effects of maximum temperature (T(max)) and residence time (RT) for each step in helium stage on ECOC measurements. Fourteen typical source samples and 20 ambient samples were collected and six temperature programs were designed for this study. It was found that EC value decreases regularly as T(max ) ascends, i.e., EC results from T(max) of 650 degrees C, 750 degrees C and 850 degrees C are 0.89 +/- 0.06, 0.76 +/- 0.10, 0.62 +/- 0.13 times EC value from T( max) of 550 degrees C, respectively, and the magnitude of EC drop (EC(d), percent) is significantly correlated with OC abundance in total carbon (R(OC/TC)), expressed as EC(d) = 66.8R(OC/TC)-14.4 (r = 0.87); pyrolized OC(POC) values are also sensitive to T(max), but there are various trends for samples with different OC constituents. On average of the samples studied here, prolonged RT reduces EC values by only 3%, almost negligible compared to the effect of T(max), and reduces POC by 9%, much less than that by previous report.     

Assessment of bacterial communities and characterization of lead-resistant bacteria in the rhizosphere soils of metal-tolerant Chenopodium ambrosioides grown on lead-zinc mine tailings

Bacterial communities in the rhizosphere soils of metal tolerant and accumulating Chenopodium ambrosioides grown in highly and moderately lead-zinc mine tailings contaminated-soils as well as the adjacent soils with low metal contamination were characterized by using cultivation-independent and cultivation techniques. A total of 69, 73, and 83 bacterial operational taxonomic units (OTUs) having 84.8-100% similarity with the closest match in the database were detected among high, moderate, and low-contamination soil clone libraries, respectively. These OTUs had a Shannon diversity index value in the range of 4.06-4.30. There were 9, 10, and 14 bacterial genera specific to high, moderate, and low metal-contaminated soil clone libraries, respectively. Phylogenetic analysis showed that the Pb-resistant isolates belonged to 8 genera. Pseudomonas and Arthrobacter were predominant among the isolates. Most of the isolates (82-86%) produced indole acetic acid and siderophores. More strains from the highly metal-contaminated soil produced 1-aminocyclopropane-1-carboxylate deaminase than the strains from the moderately and lowly metal-contaminated soils. In experiments involving canola grown in quartz sand containing 200 mg kg⁻¹ of Pb, inoculation with the isolated Paenibacillusjamilae HTb8 and Pseudomonas sp. GTa5 was found to significantly increase the above-ground tissues dry weight (ranging from 19% to 36%) and Pb uptake (ranging from 30% to 40%) compared to the uninoculated control. These results show that C. ambrosioides harbor different metal-resistant bacterial communities in their rhizosphere soils and the isolates expressing plant growth promoting traits may be exploited for improving the phytoextraction efficiency of Pb-polluted environment.     

Occurrence, compositional patterns, and possible sources of polybrominated diphenyl ethers in agricultural soil of Shanghai, China

The present study analyzed surface soil collected from agricultural region of Shanghai to determine the occurrence, compositional patterns and possible sources of polybrominated diphenyl ethers (PBDEs). The results showed that 32 PBDEs were detected among 44 target PBDEs. Total PBDE concentrations ranged from 129 to 1245 ng kg⁻¹ with a mean of 429 ng kg⁻¹. BDE209 was the predominant congener in a range of 33.2-796 ng kg⁻¹ with a mean of 254 ng kg⁻¹. Meanwhile, BDE47, BDE49, BDE153, BDE190, and BDE99 have the most abundant with high concentrations and detectable frequencies. PBDE congeners and homologues analysis and principal component analysis (PCA) also revealed that the major source of PBDE in the soil samples was associated with the prevalent use of technical decabromodiphenyl ether (Deca-BDE) and pentabromodiphenyl ether (Penta-BDE). The correlation analysis proved that there was a significant correlation between total organic carbon (TOC) and lower brominated PBDEs, indicating the significant diffuse nature of the sources of these congeners.     

China’s wastewater discharge standards in urbanization

Background and purpose

China's environmental problems and pollution control have global implications. China??s water pollution has been increasing with its urbanization and industrialization. Although great efforts have been taken to keep its wastewater discharge standards in pace with the water pollution development and technological advances, many challenges remain. A summary of the past achievements and lessons as well as the current problems in water pollution may provide a basis for future improvements in China and a reference for other countries.

Methods

Statistical data are summarized to reveal the evolution of China??s population, wastewater discharge and corresponding discharge standards over the past four decades. In particular, the specific control indexes and number of controlled items are discussed in details. The present water pollution situation is clearly illustrated by the water pollution map and the water quality distribution diagram. A comparison between China??s present wastewater discharge standards and those in the USA and the EU are also presented to find the possibilities for future improvement.

Results

The historical origins, major challenges and future perspectives of China??s wastewater discharge standards are overviewed. The barriers and ongoing efforts for standards formulation and implementation are highlighted. Some suggestions for future endeavors are given.

Conclusions

China??s wastewater discharge standard system has seen significant improvement over the past decades, but it still has many defects and limitations. Nonetheless, unprecedented great efforts are underway to address all these challenges. More stringent standards and subsequently a cleaner water environment in China can be expected in the near future.     

Degradation and detoxification of acetochlor in soils treated by organic and thiosulfate amendments

This work investigated the degradation and detoxification of acetochlor in a soil amended with an organic fertilizer or sodium thiosulfate (STS). Over an incubation period of 28 d, the residual acetochlor was measured, soil dehydrogenase activity was determined, and major degradates were identified. Results show that high-concentration acetochlor was persistent in the soil, as indicated by the depression in soil dehydrogenase activity. When the soil was amended with the organic fertilizer, the soil dehydrogenase activity was stimulated by supplemented nutrients, which resulted in a higher degradation of acetochlor. While STS did not significantly stimulate the soil dehydrogenase activity, acetochlor degraded more rapidly in STS-amended soil than in organic-amended soil. The Wright-Hobbie plots show that the influence of initial acetochlor concentration on degradation was dependent on the amendments. While the organic amendment resulted in the same degradate of acetochlor ethanesulfonic acid as in unamended soil, the STS amendment produced dechlorinated acetochlor thiosulfonic acid. The degradation of acetochlor in organic- and STS-amended soils thus occurred via different mechanisms. Further tests show that both degradates were less toxic to green algae than acetochlor. Both organic and STS amendments thus effectively degrade and detoxify acetochlor in soils.     

Characterization of heavy metal-resistant endophytic bacteria from rape (Brassica napus) roots and their potential in promoting the growth and lead accumulation of rape

Two lead (Pb)-resistant endophytic bacteria were isolated from rape roots grown in heavy metal-contaminated soils and characterized. A pot experiment was conducted for investigating the capability of the two isolates to promote the growth and Pb uptake of rape from Pb-amended soil. The two isolates were identified as Pseudomonas fluorescens G10 and Microbacterium sp. G16 based on the 16S rDNA gene sequence analysis. Strains G10 and G16 exhibited different multiple heavy metal and antibiotic resistance characteristics and increased water-soluble Pb in solution and in Pb-added soil. Root elongation assays demonstrated increases in root elongation of inoculated rape seedlings compared to the control plants. Strain G16 produced indole acetic acid, siderophores and 1-aminocyclopropane-1-carboxylate deaminase. Increases in biomass production and total Pb uptake in the bacteria-inoculated plants were obtained compared to the control. The two strains could colonize the root interior and rhizosphere soil of rape after root inoculation.