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Abstract: Receptor models are useful tools to identify sources of a specific pollutant and to estimate the quantitative contributions of each source based on environmental data. This paper reports on similarities and differences in results achieved when testing three receptor models for estimating the sources of polycyclic aromatic hydrocarbons (PAHs) in soils from Huanghuai Plain, China. The three tested models are Principal Component Analysis with Multiple Linear Regression (PCA-MLR), Positive Matrix Factorization (PMF) and Unmix. Overall source contributions as well as modeled ∑PAHs concentrations compared well among models. All three models apportioned three common PAH sources: wood/biomass burning, fossil fuel combustion and traffic emission, which contributed on average 27.7%, 53.0% and 19.3% by PCA-MLR, 36.9%, 27.2% and 16.3% by PMF, and 47.8%, 21.1% and 18.3% by Unmix to the total sum of PAHs (∑PAHs), respectively. Moreover, the spatial evolution of the common sources were well correlated among models (r=0.83–0.99, p <0.001). In addition, the PMF and Unmix models allowed segregating an additional source from the fossil fuel combustion source, with 19.6% and 11.8% contributions to ∑PAHs, respectively. The current findings further validate that different receptor models provide divergent source profiles, which are mainly attributed to both the model itself and/or the underlying dataset. It is therefore generally recommended to apply multiple techniques to determine the source apportionment in order to minimize individual-method weaknesses and thereby to strengthen the conclusion. [Copyright &y& Elsevier]

Abstract: Soil erosion is a major global environmental problem that has caused many issues involving land degradation, sedimentation of waterways, ecological degradation, and nonpoint source pollution. Therefore, it is significant to understand the processes of soil erosion and sediment transport along rivers, and this can help identify the erosion prone areas and find potential measures to alleviate the environmental effects. In this study, we investigated soil erosion and identified the most seriously eroded areas in the East River Basin in southern China using a physically-based model, Soil and Water Assessment Tool (SWAT). We also introduced a classical sediment transport method (Zhang) into SWAT and compared it with the built-in Bagnold method in simulating sediment transport process along the river. The derived spatial soil erosion map and land use based erosion levels can explicitly illustrate the identification and prioritization of the critical soil erosion areas in this basin. Our results also indicate that erosion is quite sensitive to soil properties and slope. Comparison of Bagnold and Zhang methods shows that the latter can give an overall better performance especially in tracking the peak and low sediment concentrations along the river. We also found that the East River is mainly characterized by sediment deposition in most of the segments and at most times of a year. Overall, the results presented in this paper can provide decision support for watershed managers about where the best management practices (conservation measures) can be implemented effectively and at low cost. The methods we used in this study can also be of interest in sediment modeling for other basins worldwide. [Copyright &y& Elsevier]

Abstract: Near surface disposal of low- and intermediate-level radioactive wastes (LILW) requires evaluating the field conditions of the candidate site. However, assessment of the site conditions may be challenging due to the limited prior knowledge of some remote sites, and various multi-disciplinary data requirements at any given site. These situations arise in China as in the rest of the industrialized world, particularly since a regional strategy for LILW disposal has been implemented to protect humans and the environment. This paper presents a demonstration of the site assessment process through a case study focusing mainly on the geologic, hydrogeologic and geochemical characteristics of the candidate site. A joint on-site and laboratory investigation, supplemented by numerical modeling, was implemented in this assessment. Results indicate that no fault is present in the site area, although there are some minor joints and fractures, primarily showing a north–south trend. Most of the joints are filled with quartz deposits and would thus function hydraulically as impervious barriers. Investigation of local hydrologic boundaries has shown that the candidate site represents an essentially isolated hydrogeologic unit, and that little or no groundwater flow occurs across its boundaries on the north or east, or across the hilly areas to the south. Groundwater in the site area is recharged by precipitation and discharges primarily by evapo-transpiration and surface flow through a narrow outlet to the west. Groundwater flows slowly from the hilly area to the foot of the hills and discharges mainly into the inner brooks and marshes. Some groundwater circulates in deeper granite in a slower manner. The vadose zone in the site was investigated specially for their significant capability for restraining the transport of radionuclides. Results indicate that the vadose zone is up to 38m in thickness and is made up of alluvial clay soils and very highly weathered granite. The vadose zone has low saturated hydraulic conductivities on the order of 10-5 cm/s and in this respect is well-suited for the disposal of LILW. The saturated formations are primarily made up of silt and moderately-to-slightly weathered granite, which exhibit even lower hydraulic conductivities, on the order of 10−6 cm/s, also favorable for restraining the transport of radionuclides. Chemical analyses indicate that the groundwaters at the site are of the HCO3–Na·Ca and HCO3·SO4–Na·Ca types and are weakly corrosive to concrete and steel. Geochemical analyses indicate that the rock and soil materials (particularly weathered granite) at the site contain very small fractions of colloidal particles and exhibit low Cation Exchange Capacities (CEC), and would therefore have limited capacity for sorption of radionuclides. Groundwater flow and solute transport models of the candidate site have been developed using MODFLOW and MT3DMS, incorporating the data obtained during the assessment program. Calibration was based on the available measured groundwater level fluctuations and tracer concentrations from in situ dispersion tests. The longitudinal dispersion coefficient as determined in calibration is equal to 5.0×10−3 m2/d. Numerical sensitivity analyses indicate that the hydraulic conductivity and the longitudinal dispersion coefficient are the key parameters controlling the transport of radionuclides, while the numerical model is not sensitive to changes in the effective porosity and the specific yield. Preliminary predictions have been performed with the calibrated model both for the natural setting of the site and the graded site in which the valleys of the site are backfilled with low permeable materials. Results indicate that the proposed site grading increases the safety of the site for disposal of LILW by reducing both the groundwater level and the hydraulic gradient and that radionuclide transport would not likely be a problem or cause groundwater contamination. Although there are some problems remaining to be addressed in future work, the conclusion of the assessment is that the conditions at this site are appropriate for LILW disposal. This study provides an example of the procedures necessary in an assessment of site conditions relevant to the safe disposal of LILW. Such an assessment is crucial to the site selection process and to subsequent environmental impact assessment. [Copyright &y& Elsevier]

Abstract: Member enterprises have a vital effect on the stability and system efficiency of an eco-industrial park (EIP), and a selection and control for them is an important part. This paper proposes a new method which is an establishment of both an access indicator system and an extendable optimal degree evaluation model. The indicator system comprises seven primary indicators and twenty-seven secondary indicators. The first three primary indicators, matching the existing industrial chains or not, park capacity and park environmental performance improvement, are proposed from the perspective of an EIP. The others including eco-design, economic benefit, utilization of resources, and pollution control, are suggested from the point of view of enterprises. This new access indicator system provides a basis for evaluating candidate enterprises. The extendable optimal degree evaluation which was proposed by Prof. Caiwen is a method to assess the satisfactoriness of all the indicators and to assign an optimal degree order to each candidate enterprise accordingly. There are four steps to conduct the evaluation after establishing the access indicator system: (1) selecting correlation function; (2) calculating correlations; (3) assigning weights and current values of indicators; and (4) calculating the optimal degree of all the candidate enterprises. The enterprises can be ranked based on optimal degree results. The highest-ranked enterprise should have the highest priority of entering the EIP. This study provides the specifics of applying the method by examining the case of Yantai Economy Technology Development Zone EIP (YTEIP) in Shandong province. The method provides a practical tool for controling enterprise access to an EIP. However, the reasonability and validity of indicators and effectiveness of the established method of extendable optimal degree evaluation merit further studies. [ABSTRACT FROM AUTHOR]

Harmful algal blooms (HABs) have drawn great attention in coastal areas worldwide in the past decades because of their multiple effects on marine ecosystems as well as public health. This study utilized geographic information system (GIS) techniques to analyze the primary data on HABs, as well as shellfish toxins data, in the East China Sea from 2000 to 2006. The frequency of HABs was mapped by kernel density estimation, and the relative risk posed by HABs was assessed based on their physical–chemical characteristics. In addition, the spatial patterns and the trend of HAB events were examined by nearest neighbor analysis and time series analysis, respectively. The results revealed that HAB events not only had an increasing trend and significant seasonality, but also were clustered in space and time. HAB events displayed a higher frequency and a higher risk in Zhejiang coastal waters, particularly in the Zhoushan Archipelago, the largest marine fishery in China. Shellfish toxins were detected in areas with high HAB risk, but were not correlated with the risk. This paper provides a novel method to assess the relative risk caused by HABs and some useful information for HAB monitoring and management and aquaculture development. [Copyright &y& Elsevier]