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1

Effect of landscape control on the spatiotemporal variability of riverine chromophoric dissolved organic matter

100%
Mu G., Li S.
Polish Journal of Environmental Studies
|
2019
|
tom 28
|
nr 2
An increase in the release of sewage discharge and stream ecosystem degradation is contributing to increased chromophoric dissolved organic matter (CDOM) in the Yinma River Watershed, which is a polluted watershed of the Songhua River. This study involves the spatiotemporal characterization of CDOM, CDOM-DOC relationships, and the influence of environmental factors (e.g., natural geographical and anthropogenic activities). Riverine waters showed higher aCDOM (335) and DOC concentrations in the spring and autumn than in the summer, and positive correlations were found between the aCDOM (335) and DOC concentrations in the summer (r = 0.90, 2-tailed, p<0.01) and autumn (r = 0.58, 2-tailed, p<0.01). Storms in May 2016 affected DOC flux from terrestrial ecosystems into the stream, and the CDOM-DOC relationship in the spring. Environmental factors such as water quality, precipitation, soil, gradient, land-use, and GDP could have affected the optical properties of CDOM (DOC). Gradient was correlated with the optical properties (2-tailed, p<0.05) of CDOM. Types of land-use, pollutant discharge from point sources, and GDP (r = 0.58, 2-tailed, p<0.05) affected the composition and creation of CDOM (DOC). The correlations among CDOM absorption parameters, gradient, and GDP were driven by samples that were related to regional terrestrial and anthropogenic pollutants. High loading of complex CDOM (DOC) inputs from anthropogenic activities combine with natural influences and constitute a challenge for CDOM (DOC)-derived pollution treatment, and treatment of pollution in the watershed.
2

Biosorption of antimony (Sb) by the cyanobacterium synechocystis sp.

81%
Zhang D., Pan X., Zhao L., Mu G.
Polish Journal of Environmental Studies
|
2011
|
tom 20
|
nr 5
Antimony (Sb) pollution has been of growing environmental concern. Little information is available on biosorption of Sb. In the present study, biosorption behavior and mechanisms of Sb(III) to the cyanobacterium Synechocystis sp. cells were investigated by batch experiments and FTIR analysis. Our study shows that Synechocystis sp. cells are a good adsorbent for Sb(III) with a sorption capacity of 4.68 mg・g⁻¹ dry weight adsorbent. The isothermal sorption data can be described by the Langmuir Isotherm and the Freundlich Isotherm. Several mechanisms were involved with biosorption of Sb to Synechocystis sp. cells and sorption to binding sites might be dominant. The sorption kinetics followed the pseudo-second order model. The adsorbed Sb is mainly located in extracellular polysaccharides (EPS) and within the cell, and a small proportion was adsorbed onto the cell wall. The proteins and polysaccharides in EPS and the polysaccharides on the cell are the main functional groups that are responsible for adsorption of Sb to Synechocystis sp. cells.
3

Biosorption of Sb(III) to exopolymers from Cyanobacterium Synechocystis sp.: a fluorescence and FTIR study

81%
Zhang D., Pan X., Mu G.
Polish Journal of Environmental Studies
|
2012
|
tom 21
|
nr 5
Antimony (Sb) pollution in Sb mining areas has been of growing environmental concern. However, limited information is available on environmental behavior and biogeochemical process of Sb. In the present study, complexation of Sb(III) with extracellular polymeric substances (EPS) from cyanobacterium Synechocystis sp. was investigated using excitation-emission matrix (EEM) fluorescence spectroscopy. Two protein-like fluorescence peaks were identified in the EEM spectra of EPS. Fluorescence of both peaks was clearly quenched by Sb(IlI). The quenching constants (logKₐ) and the binding constants (logKb) for peaks A and B were in the range of 3.21-4.13 and 3.22-4.14, respectively. The interaction between EPS and Sb(III) is spontaneous and endothermic. The binding of Sb(III) to EPS is dominated by the hydrogen bonding and Van der waals forces. FTIR analysis showed that polysaccharides in EPS also participated in complexation EPS with Sb(III).
4

Evaluating CDOM sources using excitation-emission matrix fluorescence and parallel factor analysis, and their links to water quality in highly polluted rivers in China

71%
Ji M., Zhang J., Li S., Mu G., Di H.
Polish Journal of Environmental Studies
|
2019
|
tom 28
|
nr 3
Chromophoric dissolved organic matter (CDOM) is a valuable optically active substance. This study examined the seasonal characteristics of fluorescent CDOM components in the Yinma and Songhua rivers, highly polluted watershed tributaries of the Songhua River, and a drinking water source for the city of Changchun, China. Parallel factor analysis (PARAFAC) and excitation-emission matrix (EEM) spectra were used to assess CDOM fluorescence. Four components attributed to CDOM in 51 water samples were identified: three were humic-like (C1, C3, and C4) and one was protein-like (C2). The average fluorescence intensities of the four components showed seasonal variation from May to November 2016. A positive linear correlation was found between components C3 and C4 (R = 0.86, p<0.001). The results from this investigation demonstrated that the frequency of rainfall and human activities may be the main factors influencing the quantity and quality of CDOM in samples collected from the watershed, and that the Yinma and Yitong rivers were polluted by terrestrial and agricultural pollution. Furthermore, the utility of combining EEM fluorescence and PARAFAC to study CDOM dynamics for different seasons and to quantify CDOM components for similar environmental (water quality) conditions was established.
5

Sb uptake and photosynthesis of Zea mays growing in soil watered with Sb mine drainage: an OJIP chlorophyll fluorescence study

61%
Pan X., Zhang D., Chen X., Li L., Mu G., Li L., Song W.
Polish Journal of Environmental Studies
|
2010
|
tom 19
|
nr 5
Maize (Zea mays) growing in soil watered with Sb mine drainage (SMD) could accumulate Sb and transferred Sb from roots to shoots. The photosynthetic processes in the leaves were clearly inhibited by SMD. Chlorophyll synthesis was inhibited. Photosystem II (PSII) was sensitive to SMD. PSII activity (FV/FM and PIABS) was reduced due to SMD. Irrigation with SMD resulted in an increase in the proportion of the closed PSII reaction centers (RCs) and a decrease in the proportion of QB binding centers. The electron transport on both the donor side and the acceptor side was inhibited by SMD. The total electron transport flux in PSII was reduced and the electron transport beyond QA¯ was the primary target site for toxicity of SMD. PSII RCs were transformed into dissipative sinks for excitation energy under stress of SMD. Sb accumulation in crops due to SMD irrigation may not only reduce crop growth and yield, but also pose a threat to food security and human health.
6

Optical properties of chromophoric dissolved organic matter in the Yinma River watershed and drinking water resource of Northeast China

51%
Li S., Zhang J., Mu G., Ha S., Sun C., Ju H., Zhang F., Chen Y., Ma Q.
Polish Journal of Environmental Studies
|
2016
|
tom 25
|
nr 3
Spectral characteristics of optically active constituents (OACs) in waters are key parameters of biooptical modeling. Comparative analyses about the differences of optical characteristics and composition between riverine and reservoir waters in the second Songhuajiang River tributaries were conducted, and the influencing factors impacting on chromophoric dissolved organic matter (CDOM) and organic carbon (DOC) were examined based on the absorption properties. Dissolved organic carbon (DOC) and total suspended matter (TSM) were significantly higher in the riverine waters, and chlorophyll-a (Chl-a) was opposite. The relationship between the CDOM absorption coefficient at specific wavelength and DOC concentration both in the riverine and reservoir waters exhibited a positive correlation (r = 0.90, p< 0.01). The close relationship between Chl-a concentration and CDOM absorption confirmed a small amount of phytoplankton absorption to total absorption in the individual samplings. Analysis of absorption ratio (E250:365), specific UV absorbance (SUVA254), and spectral slope ratio (Sr) indicated that CDOM in riverine waters had lower aromaricity, molecular weight, and vascular plant contributions than in reservoir waters. Furthermore, non-algal particles played an important role in the total non-water absorption for riverine waters, and CDOM was dominant in the reservoir waters. This indicated that the Yinma River watershed was strongly influenced by the artificial discharge. As a parameter of the bio-optical model, the spectral characteristics of CDOM could help to adjust derived algorithms based on remote sensing and to estimate the dissolved organic carbon flux.
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