Effects of photodegradation on the composition characteristics and metal binding behavior of sediment-derived dissolved organic matter (SDOM) in nansi lake, China.

Sediment-derived dissolved organic matter (SDOM) is instrumental in the cycling of nutrients and heavy metals within lakes, influencing ecological balance and contaminant distribution. Given the influence of photodegradation on the alteration and breakdown of SDOM, further understanding of this process is essential. In this research, the properties of the SDOM photodegradation process and its metal-binding reactions in Nansi Lake were analyzed using the EEM-PARAFAC and 2D-SF/FTIR-COS techniques.

Composition characteristics and metal binding behavior of macrophyte-derived DOM (MDOM) under microbial combined photodegradation: A state closer to actual macrophytic lakes.

In actual lakes, the "unstable components" of macrophyte-derived DOM (MDOM) are always degraded and cannot exist abidingly, but the environmental impact brought by it is ignored. In this study, MDOM from Potamogeton crispus was extracted to carry out microbial combined photodegradation (M-Photodegradation) and fluorescence titration experiments. Then the traits and metal binding reaction of MDOM under M-Photodegradation were analysed and compared with the features of lake-derived DOM (LDOM) from point monitoring of Dongping Lake through EEM-PARAFAC, 2D-SF-COS, and 2D-FTIR-COS.

Properties and metal binding behaviors of sediment dissolved organic matter (SDOM) in lakes with different trophic states along the Yangtze River Basin: A comparison and summary.

The nature of sediment dissolved organic matter (SDOM) can reflect the environmental background, nutritional status and human activities and is an important part of lakes. The differences in the binding capacity of heavy metals and organic matter in lake sediments with different trophic states at the catchment scale and the mechanism of the differences in binding are still unclear. To solve this problem, we collected bulk SDOMs (< 0.

Regional-scale investigation of the molecular weight distribution and metal-binding behavior of dissolved organic matter from a shallow macrophytic lake using multispectral techniques.

In this work, based on excitation-emission matrix spectroscopy combined with parallel factor analysis (EEM-FARAFAC) and two-dimensional correlation analysis of synchronous fluorescence spectroscopy, Fourier transform infrared spectroscopy, and combination of two spectra (2D-SF-COS, 2D-FTIR-COS, and Hetero-2D-COS), the characteristics and metal-binding behaviors of DOM in Dongping Lake were explored for molecular weight (MW), fluorescence components, and functional groups. The results showed that the entire lake was governed by protein-like materials with low MW(< 1 kDa). The complexation occurred preferentially in protein-like materials for bulk DOM after adding copper (Cu) and lead (Pb), which were changed by fractionation for MW.

Physicochemical properties and greenhouse gas emissions of water body during the decomposition of Potamogeton crispus with different values of initial debris biomass.

A sediment-water mesocosm experiment was set up to identify the effects of different debris biomass P. crispus decomposition on water body physicochemical properties and greenhouse gas emissions in Dongping Lake, a typical shallow macrophytic lake in the north of China. The results indicated that the decomposition of high biomass (BL-2) of P.

Characterizing variations in dissolved organic matter (DOM) properties in Nansi Lake: a typical macrophytes-derived lake in northern China.

Nansi Lake is the largest lake along the eastern route of China's South-to-North Water Diversion Project (SNWDP). It is divided into the upper lake and the lower lake by a dam. By using UV-Vis spectroscopy, synchronous fluorescence (SF) spectroscopy, excitation-emission matrix and parallel factor analysis (EEM-PARAFAC), spatial, and temporal differences in the properties of dissolved organic matter (DOM) were found in the 2 areas of Nansi Lake under different hydrological conditions.

Biological denitrification in a macrophytic lake: implications for macrophytes-dominated lake management in the north of China.

Denitrification plays an important role in nitrogen (N) removal in freshwater ecosystems. Aquatic plants might have an impact on the sediment denitrification of water body, especially in macrophytes-dominated lake; however, there were different opinions about it. Our hypothesis was that the sediment denitrification rates differ significantly in different vegetation zones and seasons because of direct and indirect effect of the aquatic plants.

Characterizing the interactions between sediment dissolved organic matter and zinc using multispectroscopic techniques.

Sediment dissolved organic matter (DOM) was collected in November 2018 from Lake Dongping, China. The lake was divided into the entrance of the Dawen River, the open region of the lake, the tourism district and the macrophyte-dominated region based on principal component analysis (PCA) of 9 DOM-related parameters. Multispectroscopic tools were used to investigate the binding of zinc (Zn) with four kinds of DOM collected from the entrance of the Dawen River (EDOM), the open area of the lake (ODOM), the macrophyte-dominated area (mainly dominated by Potamogeton crispus L.

Metal release/accumulation during the decomposition of Potamogeton crispus in a shallow macrophytic lake.

Changes in metal concentrations in the litter of Potamogeton crispus were monitored during a consecutive 40-day in situ decomposition experiment using the litterbag method. The accumulation index was calculated and used to indicate the changes in the metals in litter. The results showed that the concentrations of Al, Cd, Cr, Fe, Mn, and Pb in litter increased significantly during the decomposition, while Cu and Zn concentrations decreased dramatically.

Vertical dissolved inorganic nitrogen fluxes in marsh and mudflat areas of the yangtze estuary.

Nitrogen (N) is a dominant macronutrient in many river-dominated coastal systems, and excess concentrations can drive eutrophication, the effects of which can include hypoxia and algal blooms. The Yangtze River in China transports a large amount of dissolved inorganic N. Therefore, it is important to understand the role of the marsh and mudflat areas within the estuary on processing this exogenous N load.

Denitrification controls in urban riparian soils: implications for reducing urban nonpoint source nitrogen pollution.

The purpose of this research was to thoroughly analyze the influences of environmental factors on denitrification processes in urban riparian soils. Besides, the study was also carried out to identify whether the denitrification processes in urban riparian soils could control nonpoint source nitrogen pollution in urban areas. The denitrification rates (DR) over 1 year were measured using an acetylene inhibition technique during the incubation of intact soil cores from six urban riparian sites, which could be divided into three types according to their vegetation.

The capability of estuarine sediments to remove nitrogen: implications for drinking water resource in Yangtze Estuary.

Water in the Yangtze Estuary is fresh most of the year because of the large discharge of Yangtze River. The Qingcaosha Reservoir built on the Changxing Island in the Yangtze Estuary is an estuarine reservoir for drinking water. Denitrification rate in the top 10 cm sediment of the intertidal marshes and bare mudflat of Yangtze Estuarine islands was measured by the acetylene inhibition method.

Heavy Metal Contamination and Assessment of Roadside and Foliar Dust along the Outer-Ring Highway of Shanghai, China.

Foliar and roadside dust samples were collected from five sites along the outer-ring highway of Shanghai, one of the biggest metropolitan areas of China, to assess heavy/toxic metal contamination. Concentrations of Zn, Cu, Ni, As, and Hg in foliar dust were higher than in roadside dust, whereas concentrations of Pb and Cd were higher in roadside dust. In the roadside dust, average concentrations of all metals except As in foliar and roadside dust samples were significantly above the background values of soil in Shanghai: the ratios between the average of samples and background values of Shanghai were in the order: Cd (25.

Nitrous oxide emissions in the Shanghai river network: implications for the effects of urban sewage and IPCC methodology.

Global nitrogen (N) enrichment has resulted in increased nitrous oxide (N(2)O) emission that greatly contributes to climate change and stratospheric ozone destruction, but little is known about the N(2)O emissions from urban river networks receiving anthropogenic N inputs. We examined N(2)O saturation and emission in the Shanghai city river network, covering 6300 km(2), over 27 months. The overall mean saturation and emission from 87 locations was 770% and 1.

A comprehensive investigation and assessment of mercury in intertidal sediment in continental coast of Shanghai.

The aims of this paper were to survey the total Hg levels and distribution character in intertidal sediment in continental coast of Shanghai, and identify the environment factors that might influence the sediment Hg concentrations, and to assess the pollution degree and potential ecological risk of Hg in sediment. Eighty-eight surface sediment samples and 18 sediment cores were collected for Hg contamination analysis. Physicochemical properties including Eh, particle size, content of total organic carbon (TOC), and acid volatile sulfide (AVS) were also measured.

Toxic heavy metal contamination and risk assessment of street dust in small towns of Shanghai suburban area, China.

The aims of this paper were to quantify the heavy metal concentrations in street dust of small towns in Shanghai suburban area compared with those in urban area, and examine their seasonal and spatial variations, and to assess their risks to water environment and local populations. Street dust samples were collected from three small towns and urban area in Shanghai in different seasons. Levels of heavy metals were determined by atomic adsorption spectrophotometer analyzer.

[Effects of sediment resuspension on nitrogen and phosphate exchange at the sediment-water interface in East Chongming Tidal Flat].

Sampling sediment and water to mimic sediment resuspension and researching its effects on nitrogen and phosphate exchange at the sediment-water interface in east Chongming tidal flat. Through the experiment, it was found that sediment resuspension causes NO3(-)-N, NH4(+)-N, NO2(-)-N and DIP releases. The release of NO3(-)-N is most marked, the increasing concentration of NO3(-)-N, NH4(+)-N, NO2(-)-N and DIP reach in turns: 11.