Evaluation of PCDD/Fs patterns emitted from incinerator via direct ambient sampling and indirect serum levels assessment of Taiwanese

The aim of this study was to evaluate the PCDD/Fs patterns in ambient air based on data information emitted from incinerator generated from ambient air measurements and those in serum. Four circular zones, namely A, B, C, and D, were identified based on simulated ambient annual average PCDD/Fs concentrations, from a selected municipal waste incinerator. Sixteen ambient samples were taken from the 4 circular zones across 4-seasons. Eighty-nine volunteers were recruited according to the demographic distribution within each zone. PCDD/Fs profiles were documented both for air and serum samples collected. Comparing to the congener patterns from ambient air and serum samples, we found that OCDD, OCDF, 1,2,3,4,6,7,8-HpCDD, and 1,2,3,4,6,7,8-HpCDF were the predominant groups among 17 congeners from both the ambient air and serum sample. And, factor analysis showed the distribution patterns of PCDD/Fs from ambient air and serum samples are almost identical across different zones, except for congener patterns of serum samples from residents in zone C. In addition, the average PCDD/Fs level significantly reduced for about 10 folds than those of the other three seasons when the incinerator was shut down in one of sampling periods. We might conclude that ambient air exposure was the most important contributor to PCDD/Fs levels in ambient air but not the single in serum. Therefore, another or more powerful source, such as occupational exposure, dietary intake or the consumption of local food, should be further investigated at the same time.     

Do economic development and population agglomeration inevitably aggravate haze pollution in China? New evidence from spatial econometric analysis

Environmental Science and Pollution Research - With sustained economic development, China’s ecological environment is becoming increasingly fragile and the problem of haze pollution is...     

Model calculating annual mean atmospheric dispersion factor for coastal site of nuclear power plant

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Distribution of Al-, Fe- and Mn-pools and their correlation in soils from two acid deposition small catchments in Hunan, China

Distribution of Al-, Fe- and Mn-pools was investigated in five forest soil profiles (consisting of four horizons) in each of two Hunan catchments (BLT and LKS) where acid deposition has been considered critical. Al- and Fe-pools were higher in BLT than those in LKS, but Mn-pools much lower in BLT. Mn-pools vary from topsoils to bottom soils, but there are different trends for different Mn speciation. Al- and Fe-pools, except amorphous Fe_ox, were positively correlated to contents of soil organic matter (OM) showed by the loss on ignition in the two catchments. Accumulation of Al- and Fe-pools may occur in the area where soil organic matter was enriched (e.g. in top soil and rhizosphere soil). However, no direct correlation is observed between Mn and OM. Acidic atmospheric deposition may affect transforming among speciations of Al-, Fe- and Mn-pools and leaching of soil Al, Fe and Mn through formation of soluble organo-metal dissolved Al which was potentially toxic, increased. There were significant correlations between Al-pools complexes or change of oxidation–reduction conditions. Mn_ex (exchangeable Mn) and Mn_ox (amorphous and organic Mn) were highly linearly correlation with soil pH values at LKS but at BLT. Under acid deposition, the availability of the nutrient Fe increased with the amount of dissolved Al, which was potentially toxic, in the two catchments. There are no significant correlations between Al_ex (exchangeable Al) and Mn_ex, Fe_ex (exchangeable Fe) and Mn_ex in this work, indicating potentially toxic Mn increase seldom accompanying with Al increase in the two catchments.     

Spatial and temporal variations of nitrogen pollution in Wen-Rui Tang River watershed, Zhejiang, China

Water quality has degraded dramatically in Wen-Rui Tang River watershed, Zhejiang, China, especially due to rapid economic development since 1995. This paper aims to assess spatial and temporal variations of the main pollutants (NH??-N, TN, BOD(5), COD(Mn), DO) of water quality in Wen-Rui Tang River watershed, using the geographic information system, cluster analysis (CA) and principal component analysis (PCA). Results showed that concentrations of BOD(5), COD(Mn), NH??-N, and TN were significantly higher in tertiary rivers than in primary and secondary rivers. From April 2006 to March 2007, the concentrations of NH? ?-N (2.25-57.9 mg/L) and TN (3.78-70.4 mg/L) in all samples exceeded Type V national water quality standards (≥2 mg/L), while 5.3% of all COD(Mn) (1.83-27.5 mg/L) and 33.6% of all BOD(5) (0.34-50.4 mg/L) samples exceeded Type V national water quality standards (COD(Mn)?≥ 15 mg/L, BOD(5)?≥ 10 mg/L). Monthly changes of pollutant concentrations did not show a clear pattern, but correlation analysis indicated that NH??-N and TN in tertiary rivers had a significant negative correlation with 5-day cumulative rainfall and monthly rainfall, while there were no significant correlations in primary and secondary rivers. The results of CA and spatial analysis showed that the northern part of Wen-Rui Tang River watershed was the most seriously polluted. This region is characterized by the high population density and industrial and commercial activities. The PCA and spatial analysis indicated that the degraded water quality is caused by anthropogenic activities and poor wastewater management.     

Low-cost and efficient adsorbent derived from pyrolysis of Jatropha curcas seeds for the removal of Cu2+ from aqueous solutions

Biochar, is a low-cost material that can be used as an alternative adsorbent for the removal of heavy metals. In this study, a low-cost and efficient adsorbent synthesised from Jatropha curcas seeds was used for the uptake of Cu²⁺ from aqueous solutions. The as-prepared adsorbent was characterised by scanning electron microscopy and Brunauer–Emmett–Teller analysis post calcination at 500 °C, its BET surface area and total pore volume were 39.62?m²?g^?1 and 0.049?m³?g^?1, respectively. Subsequently, the effects of initial pH of the solution, contact time, and adsorbent material dosage on the adsorption of Cu²⁺ by the prepared adsorbent were investigated. The as-prepared adsorbent exhibited a high performance, with a maximum adsorption amount of 32.895?mg?g^?1 for Cu²⁺ at pH 5.0 and 25 °C, owing to the presence of ?OH, C=O, C–O, Si-O-Si, and O-Si-O on its surface. The predominant Cu²⁺ adsorption mechanism was assumed to be ion exchange. Notably, the Cu²⁺ adsorption could attain equilibrium within 90?min. In addition, the fact that the Langmuir model was a better fit than the Freundlich model for the isotherm data of Cu²⁺ adsorption by the as-prepared adsorbent suggested that the adsorption of Cu²⁺ was a monolayer adsorption process.     

Assessment of pollution of potentially harmful elements in soils surrounding a municipal solid waste incinerator,China

We assessed the contamination levels of Mn, Zn, Cr, Cu, Ni, Pb, As and Hg and the risks posed by these potentially harmful elements in top-soils around a municipal solid waste incinerator (MSWI).We collected 20 soil samples, with an average pH of 8.1, and another fly ash sample emitted from the MSWI to investigate the concentrations of these elements in soils. We determined the concentrations of these elements by inductively coupled plasma–optical emission spectrometer (ICP-OES), except for Hg, which we measured by AF-610B atomic fluorescence spectrometer (AFS). We assessed the risks of these elements through the use of geoaccumulation index (I _geo), potential ecological risk index (RI), hazard quotient (HQ _i ) and cancer risk (Risk _i ). The results showed that concentrations of potentially harmful elements in soil were influenced by the wind direction, and the concentrations of most elements were higher in the area northwest of the MSWI, compared with the area southeast of the incinerator, with the exception of As; these results were in accordance with those results acquired from our contour maps. According to the I _geo values, some soil samples were clearly polluted by Hg emissions. However, the health risk assessment indicated that the concentrations of Hg and other elements in soil did not pose non-carcinogenic risks to the local populations. This was also the case for the carcinogenic risks posed by As, Cr, and Ni. The carcinogenic risk posed by As was higher, in the range 6.49 × 10^–6–9.58 × 10^–6, but this was still considered to be an acceptable level of risk.

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Effects of exotic Spartina alterniflora on rhizosphere and endophytic bacterial community structures and diversity in roots of native mangroves北大核心CSCD

Root-associated microbial communities are very important for biogeochemical cycles of carbon, nitrogen, and sulfur in wetland ecosystems, and help to enhance the mechanisms of plant invasions. In the estuary of Jiulong River (China), Spartina alternifiora has widely invaded Kandelia obovata-dominated habitats, making it necessary to investigate the influence of rootassociated bacteria. The endophytic and rhizosphere bacterial community structures associated with selected plant species were investigated using the barcoded Illumina paired-end sequencing technique. The diversity indices of bacteria associated with the roots of S. alterniflora were higher than those of the transition stands and K. obovata monoculture. Using principal coordinate analysis with UniFrac metrics, the comparison of diversity showed that all samples could be significantly clustered into three major groups, according to the bacterial communities of origin. Four phyla, namely, Proteobacteria, Bacteroidetes, Chloroflexi, and Firmicutes, were abundant in the rhizoplane of the two salt marsh plants, whereas Cyanobacteria and Proteobacteria were the more abundant endophytic bacteria. Proteobacteria, Bacteroidetes, Chloroflexi, and Firmicutes in the rhizosphere bacteria of S. alterniflora accounted for 78.0%, 5.6%, 3.3%, and 1.6%, respectively. Members of the phyla Spirochaetes and Chloroflexi were found among the endophytic bacteria of S. alterniflora and K. obovata, respectively. Using linear discriminate analysis, we found some dominant rhizoplane and endophytic bacteria, including Pseudoalteromonadaceae, Vibrionaceae, Methylophilaceae, and Desulfovibrio, which could potentially affect the carbon, nitrogen, and sulfur cycles. Of interest was that endophytic bacteria were more sensitive to plant invasion than rhizosphere bacteria. Thus, the results provide evidence for the isolation of functional bacteria and the effects of root-associated microbial groups on S. alterniflora invasions. © 2018 Science Press. All rights reserved.     

双室和单室微生物燃料电池的研究及比较

微生物燃料电池(MFC)可分为双室和单室燃料电池.简述了双室和单室MFC的工作机制,综述了双室MFC中阳极(材料)、阴极(材料)、分割材料和单室MFC中"二合一"、"三合一"型以及无膜型电池的特点,比较并分析了双室和单室MFC在构型上的优缺点,以及两者在内阻、功率密度和库仑效率等方面产生差异的原因,展望了MFC的发展前景.