[Simulation of Pollution Apportionment and Optimization of Control Methods in Watershed Scale: A Case Study of the Shun'an Watershed in Tongling City].

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. The results showed that the new method could accurately quantify the impacts of planting industry, rural life, livestock and poultry breeding, aquaculture, industrial sewage, and domestic sewage in the watershed and evaluate the overall effects of various measures. The multi-objective optimization algorithm provided a cooperative multi-source pollution control scheme with higher cost performance and better environmental benefit by comparing the cost effectiveness of various schemes systematically. The optimization scheme showed that total nitrogen could be reduced by 1274.24 t·a-1 in wet years, 855.24 t·a-1 in normal years, and 381.96 t·a-1 in dry years. Total phosphorus was reduced by 321.42 t·a-1 in wet years, 159.80 t·a-1 in normal years, and 42.93 t·a-1 in dry years, such that the water quality reached the surface class Ⅲ water quality standard. These research results can be extended to other watersheds and provide a method reference for water environment protection under the background of the high-quality development of watersheds.

Iron-Catalyzed Tertiary Alkylation of Terminal Alkynes with 1,3-Diesters via a Functionalized Alkyl Radical.

Direct oxidative C(sp)-H/C(sp3 )-H cross-coupling offers an ideal and environmentally benign protocol for C(sp)-C(sp3 ) bond formations. As such, reactivity and site-selectivity with respect to C(sp3 )-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. The reaction is suitable for an array of substrates and proceeds in a highly selective manner even employing alkanes containing other tertiary, benzylic, and C(sp3 )-H bonds alpha to heteroatoms. Elaboration of the products enables the synthesis of a series of versatile building blocks. Control experiments implicate the in situ generation of a tertiary carbon-centered radical species.

Selective Dehydrogenative Acylation of Enamides with Aldehydes Leading to Valuable ß-Ketoenamides.

We 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 ß-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 Z-selectivity was observed. Late-stage modifications of complex molecules and versatile synthetic utility of ß-ketoenamides further highlight the practicability of this transformation.

[Pollution Characteristics and Health Risk Assessment of Microorganism Pollutions in the Beiyun River].

Microorganism 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 105 MPN·L-1. During the normal season and dry season, the microbial amount was approximately 103-105 MPN·L-1. Therefore, no obvious change could be observed. The fecal pollution in the agricultural river sections was the most severe, and the water quality of over 60% of these river sections was below the state Grade V level. The fecal microbial biomass of some urban river sections increased from 103 MPN·L-1 to 106MPN·L-1 after the rainfall event, indicating an obvious change of fecal microbial pollution during the rainfall process. For the Beiyun River, the exposure risk of the fecal microbial biomass was mainly between 0.015-0.035, while the Lianhua River, Macao River, lower reaches of Qinghe River, and lower reaches of Wenyu River were hotspots for contamination. Greater attention should be paid to these areas.

[Speciation and Risk Characteristics of Heavy Metals in the Sediments of the Yangtze Estuary].

Based 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%. The sediment quality guidelines of the Yangtze Estuary for As, Cd, Cr, Cu, Hg, Ni, Pb, Zn were 43.29, 0.672, 79.65, 19.08, 0.569, 339.09, 30.87, 411.36 µg · g⁻¹, respectively. Cu had the highest ecological risk to aquatic organisms. The upstream of Yangtze Estuary was mainly affected by Yangtze River runoff, where the risks were relatively high in wet season and relatively low in normal and dry seasons. However, the downstream of the estuary was mainly affected by municipal sewage of cities like Shanghai, where the risks were relatively high, especially in normal and dry seasons. There were three different relationships between the ecological risks and speciation of the eight heavy metals.

Investigation of the interaction between As and Sb species and dissolved organic matter in the Yangtze Estuary, China, using excitation-emission matrices with parallel factor analysis.

The 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. The tryptophan-like substance represented by component 2 was the dominant component and played an important role in the complexation between DOM and As/Sb. The results of complexation modeling demonstrated that the binding capacity of trivalent As/Sb with DOM was higher than that of pentavalent As/Sb with DOM. The DOM from the north nearshore area with the most acidic functional groups and greatest aromaticity possessed the highest binding capacity for trivalent and pentavalent As/Sb. The increase in the UV absorbance and the charge neutralization further indicated the interaction between As/Sb and DOM. The higher binding capacity of Sb(III) with DOM was mainly due to the hydroxyl and carboxyl groups. Our study demonstrates that the use of the advanced EEM-PARAFAC method in fluorescence quenching studies is very useful for evaluating the properties of DOM-pollutant interactions.

[Spatial distribution and pollution source identification of agricultural non-point source pollution in Fujiang watershed].

In 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 3.10 t x km(-2). Agricultural NPS TN loading mainly distributed over dry lands, Mianyang city and gentle slope areas; high loading intensity areas were dry lands, Deyang city and gentle slope areas. Agricultural land use, of which contribution rate was 62. 12%, was the most important pollution source; fertilizer loss in dry lands, of which contribution rate was 50.49%, was the prominent. Improving methods of agricultural cultivation, implementing "farm land returning to woodland" policy, and enhancing treatment efficiency of domestic sewage and livestock waster wate are effective measures.

Parameter uncertainty analysis of non-point source pollution from different land use types.

Land 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. The model outputs selected in this study consisted of runoff, sediment yield, organic nitrogen (N), and total phosphorus (TP). The results indicated that the uncertainty conferred by the parameters differed among the three land use types. In forest and grassland, the parameter uncertainty in NPS pollution was primarily associated with runoff processes, but in plantation, the main uncertain parameters were related to runoff process and soil properties. Taken together, the study suggested that adjusting the structure of land use and controlling fertilizer use are helpful methods to control the NPS pollution in the Daning River Watershed.

[Effects of parameter spatial distribution on non-point pollution source model].

The 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. The max relative error is 19.6% for the annual mean flow under different watershed delineation scenarios. The flow increase first and then decrease with the number of sub-watersheds. The efficiencies coefficient is 0.52 - 0.82 for annual mean flow and 0.80 - 0.83 for monthly mean flow under six delineation scenarios. Outlet nutrients simulations are slightly affected by changes in watershed delineation scenarios. The relative errors of organic nitrogen and organic phosphorous are 16.2% and 7.7% respectively and no explicit trend is observed.

[Simulation of nonpoint source pollution load in Maoping River watershed].

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. The validated model was then be used to simulate the nutrients load in Maoping River watershed. The Nash-Sutcliffe coefficient of flow, nitrogen and phosphorous was 0.71, 0.51 and 0.62 with the minimum relative error 1.8%, 1.1% and 10% respectively. Despite achieving the relatively lower resemblance between observed and simulated phosphorous and nitrogen load the model showed good agreement in simulating runoff. The results showed that 102.5t nitrogen and 9.46t phosphorous entered intoYangtze River during May to October 2004. One of the important reason that caused the water quality deterioration can be attributed to the nonpoint source pollution.

[Effect of land use/cover change on pollution load of non-point source in upper reach of Yangtze River Basin].

On 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 1.16 x 10(6) tons in 2000 on the premise of taking no account of basin loss. It reduced year by year basically in the past several decades and so did TP load which decreased from 3.7 x 10(4) tons in 1970s' to 3.5 x 10(4) tons in 2000. As far as province, land use and water system are considered, Sichuan province, crop land grass, Jinsha river and Jialing river are important contributories of NPS pollution load in study area. Intensity analysis shows the region of Chongqing municipality and the watershed of Jialing River are two highest NPS pollution load areas, and these areas should be gained more attention in the future. Using the method put forward in this paper, NPS pollution space simulation is carried out in large scale basin such as upper reach of Yangtze River Basin precisely basically.