The protection of the Yangtze River is an important national strategy in China, but it faces many problems such as difficult water environment protection, unclear pollution sources, and low integration of measures. Aimed at addressing watershed scale multi-source pollution together with facing the bottleneck method, by combining research data analysis, mechanism model, and intelligent algorithm optimization, this study built the framework for accurate pollution apportionment, measures evaluation, and overall measure optimization. Shun'an watershed in Tongling City of Anhui Province was set as an example for the application.
View Article and Find Full Text PDFDirect oxidative C(sp)-H/C(sp )-H cross-coupling offers an ideal and environmentally benign protocol for C(sp)-C(sp ) bond formations. As such, reactivity and site-selectivity with respect to C(sp )-H bond cleavage have remained a persistent challenge. Herein is reported a simple method for iron-catalyzed/silver-mediated tertiary alkylation of terminal alkynes with readily available and versatile 1,3-dicarbonyl compounds.
View Article and Find Full Text PDFWe have presented a unique example of dehydrogenative acylation of enamides with aldehydes enabled by an earth-abundant iron catalyst. The protocol provides the straightforward access to valuable β-ketoenamides with ample substrate scope and excellent functional group tolerance. Notably, distinct C-H acylation of enamide rather than at N-H moiety site occurs with absolute -selectivity was observed.
View Article and Find Full Text PDFMicroorganism pollution in rivers is of great importance to the protection of watershed water quality and public health management. As a typical watershed of the Haihe River watershed, the Beiyun River was chosen as the study area, and the characteristics and health risk of microorganism pollution were assessed from a comprehensive perspective. The results showed that the microbial contamination of the fecal sources was serious during the wet season, and the microbial amount at most river sections was more than 10 MPN·L.
View Article and Find Full Text PDFBased on the investigation on the distribution of total contents and speciation of 8 heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, Zn) in the surface sediments at 14 typical sites of the Yangtze Estuary during three hydrological seasons ( wet, normal, and dry seasons) , this study applied equilibrium partitioning approach to build the sediment quality guidelines (SQGs) of the Yangtze Estuary, and assessed ecological risks of the heavy metals. The relationship between ecological risk and speciation of heavy metals was also revealed. The results showed that, except for Cd, the residual fraction was the main speciation of heavy metals, especially for As, Cr and Hg, their residual fraction proportions were all over 90%.
View Article and Find Full Text PDFThe interactions between trivalent or pentavalent As/Sb and dissolved organic matter (DOM) in four regions (the river channel, the adjacent coastal area, and the northern and southern nearshore areas) of the Yangtze Estuary, China, were studied using fluorescence quenching titration combined with excitation-emission matrix spectroscopy and parallel factor analysis (PARAFAC). The As/Sb-DOM complexation characteristics were investigated using FTIR and UV absorbance spectroscopy and zeta potential analysis. Four protein-like components and one humic-like component were identified in the DOM from the Yangtze Estuary, China, by PARAFAC analysis.
View Article and Find Full Text PDFIn order to provide regulatory support for management and control of non-point source (NPS) pollution in Fujiang watershed, agricultural NPS pollution is simulated, spatial distribution characteristics of NPS pollution are analyzed, and the primary pollution sources are also identified, by export coefficient model (ECM) and geographic information system (GIS). Agricultural NPS total nitrogen (TN) loading was of research area was 9.11 x 10(4) t in 2010, and the average loading was intensity was 3.
View Article and Find Full Text PDFLand use type is one of the most important factors that affect the uncertainty in non-point source (NPS) pollution simulation. In this study, seventeen sensitive parameters were screened from the Soil and Water Assessment Tool (SWAT) model for parameter uncertainty analysis for different land use types in the Daning River Watershed of the Three Gorges Reservoir area, China. First-Order Error Analysis (FOEA) method was adopted to analyze the effect of parameter uncertainty on model outputs under three types of land use, namely, plantation, forest and grassland.
View Article and Find Full Text PDFThe SWAT model was used to simulate the effects of parameter spatial distribution on flow and nutrients loadings in the Daning river watershed. It was first calibrated and validated using the measured data for the period of 2000 - 2004. Then the model was used to simulate the effects of watershed delineation scenarios on flow and nutrients loadings, using six watershed delineations, each with a different number of sub-watersheds.
View Article and Find Full Text PDFHuan Jing Ke Xue
November 2006
The nitrogen and phosphorous transport in the Maoping River watershed was modelled using the SWAT model, which simulates the water cycle and the transformation of nutrients. The model was first calibrated by comparing the observed and the simulated data from May to October 2004, and then validated. The Nash-Sutcliffe coefficient (R2), the mean square root error (RMSE) and the relative error(CV) were used to test the agreement between observed and simulated data.
View Article and Find Full Text PDFOn the basis of other scholars' researches, utilizes export coefficient model, adopts RS and GIS techniques, estimates the non-point source (NPS) pollution load of upper reach of Yangtze River Basin, and simulates its special distribution. The results indicates that the total nitrogen load caused by land use drop from 1.23 x 10(6) tons in 1970s' to 1.
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