Chaoyang Liu

Site-specific risk assessment and integrated management decision-making: A case study of a typical heavy metal contaminated site, Middle China

ABSTRACT A typical contaminated land was spatially investigated and assessed based on Chinese guidelines to establish remediation strategy for exploring the shortcomings of the current guidelines to suggest improvements. Results showed that Cr, As, Pb, and Cd should be regarded as the priority pollutants under sensitive land use, while Cr and As should be regarded as the priority pollutants under insensitive land use. Ingestion of soil for each studied metal appeared to be the main exposure pathway under both the land uses. The calculated screening values of the priority metals were conservative to certain extent—even some were lower than their background values. Therefore, an integrated risk management strategy was suggested and the hierarchic clean-up values were proposed considering the health risk, local background value, land remediation cases, current remediation technology, and financial cost. Consequently, it was suggested the clean-up values of Cr(VI), Cr, As, Pb, and Cd, under future sensitive land use, should be 7.5, 1000, 30, 250, and 1.4 mg/kg in the first class control layer, respectively. For future insensitive land use, the clean-up values of Cr(VI), Cr, As, Pb, and Cd should be 20.4, 8000, 60, 580, and 4.3 mg/kg in the first class control layer, respectively.

Spatial Distribution and Fuzzy Health Risk Assessment of Trace Elements in Surface Water from Honghu Lake

Previous studies revealed that Honghu Lake was polluted by trace elements due to anthropogenic activities. This study investigated the spatial distribution of trace elements in Honghu Lake, and identified the major pollutants and control areas based on the fuzzy health risk assessment at screening level. The mean total content of trace elements in surface water decreased in the order of Zn (18.04 μg/L) > Pb (3.42 μg/L) > Cu (3.09 μg/L) > Cr (1.63 μg/L) > As (0.99 μg/L) > Cd (0.14 μg/L), within limits of Drinking Water Guidelines. The results of fuzzy health risk assessment indicated that there was no obvious non-carcinogenic risk to human health, while carcinogenic risk was observed in descending order of As > Cr > Cd > Pb. As was regarded to have the highest carcinogenic risk among selected trace elements because it generally accounted for 64% of integrated carcinogenic risk. Potential carcinogenic risk of trace elements in each sampling site was approximately at medium risk level (10−5 to 10−4). The areas in the south (S4, S13, and S16) and northeast (S8, S18, and S19) of Honghu Lake were regarded as the risk priority control areas. However, the corresponding maximum memberships of integrated carcinogenic risk in S1, S3, S10–S13, S15, and S18 were of relatively low credibility (50–60%), and may mislead the decision-makers in identifying the risk priority areas. Results of fuzzy assessment presented the subordinate grade and corresponding reliability of risk, and provided more full-scale results for decision-makers, which made up for the deficiency of certainty assessment to a certain extent.

Investigation, Pollution Mapping and Simulative Leakage Health Risk Assessment for Heavy Metals and Metalloids in Groundwater from a Typical Brownfield, Middle China

Heavy metal and metalloid (Cr, Pb, Cd, Zn, Cu, Ni, As and Hg) concentrations in groundwater from 19 typical sites throughout a typical brownfield were detected. Mean concentrations of toxic metals in groundwater decreased in the order of Cr > Zn > Cu > Cd > Ni > Pb > Hg > As. Concentration of Cr6+ in groundwater was detected to further study chromium contamination. Cr6+ and Cd in groundwater were recommended as the priority pollutants because they were generally 1399-fold and 12-foldgreater than permissible limits, respectively. Owing to the fact that a waterproof curtain (WPC) in the brownfield is about to pass the warranty period, a steady two-dimensional water quality model and health risk assessment were applied to simulate and evaluate adverse effects of Cr6 + and Cd on the water quality of Xiangjiang River and the drinking-water intake of Wangcheng Waterworks. The results indicated that when groundwater in the brownfield leaked with valid curtain prevention, the water quality in Xiangjiang River and drinking-water intake downstream were temporarily unaffected. However, if there was no curtain prevention, groundwater leakage would have adverse impact on water quality of Xiangjiang River. Under the requirements of Class III surface water quality, the pollution belt for Cr6+ was 7500 m and 200 m for Cd. The non-carcinogenic risk of toxic metals in Xiangjiang River exceeded the threshold in a limited area, but did not threaten Wangcheng Waterworks. By contrast, the carcinogenic risk area for adults was at a transverse distance of 200 m and a longitudinal distance of 18,000 m, which was close to the Wangcheng Waterworks (23,000 m). Therefore, it was essential to reconstruct the WPC in the brownfield for preventing pollution diffusion.

Removal of organic matter and heavy metals of low concentration from wastewater via micellar-enhanced ultrafiltration: an overview

As a new and effective means of wastewater treatment, the micellar-enhanced ultrafiltration (MEUF) has been extensively studied. In this paper, MEUF was introduced from the aspects of theory basis, ultrafiltration membranes, and surfactants. Additionally, the latest research achievements in removing organic matter and heavy ions, its application in actual wastewater, and the characterization parameters of MEUF were introduced and summarized. Then, influences and mechanisms of the primary operation parameters, including surfactant concentration, pH, electrolytes, and transmembrane pressure on the performance of the MEUF process were analyzed. Finally, existing problems in the MEUF process were identified and developmental trends were predicted.

Spatial Distribution, Chemical Fraction and Fuzzy Comprehensive Risk Assessment of Heavy Metals in Surface Sediments from the Honghu Lake, China

Spatial concentrations and chemical fractions of heavy metals (Cr, Cu, Pb, Zn and Cd) in 16 sampling sites from the Honghu Lake were investigated using an atomic absorption spectrophotometer and optimized BCR (the European Community Bureau of Reference) three-stage extraction procedure. Compared with the corresponding probable effect levels (PELs), adverse biological effects of the studied five sediment metals decreased in the sequence of Cr > Cu > Zn > Pb > Cd. Geo-accumulation index (Igeo) values for Cr, Cu, Pb and Zn in each sampling site were at un-contamination level, while the values for Cd varied from un-contamination level to moderate contamination level. Spatially, the enrichment degree of Cd in lower part of the South Lake, the west part of the North Lake and the outlet were higher than the other parts of Honghu Lake. For metal chemical fractions, the proportions of the acid-extractable fraction of five metal contents were in the descending order: Cd, Cu, Zn, Pb and Cr. Cd had the highest bioaccessibility. Being the above indexes focused always on heavy metals’ total content or chemical fraction in deterministic assessment system, which may confuse decision makers, the fuzzy comprehensive risk assessment method was established based on PEI (Potential ecological risk index), RAC (Risk assessment code) and fuzzy theory. Average comprehensive risks of heavy metals in sediments revealed the following orders: Cd (considerable risk) > Cu (moderate risk) > Zn (low risk) > Pb > Cr. Thus, Cd and Cu were determined as the pollutants of most concern. The central part of South Honghu Lake (S4, S5, S6, S9, S12 and S14), east part of the North Honghu Lake (S1) and outlet of outlet of the Honghu Lake (S10) were recommended as the priority control areas. Specifically, it is necessary to pay more attention to S1, S4, S5, S6, S9 and S16 when decision making for their calculated membership values (probabilities) of adjacent risk levels quite close.

Comparison of Toxic Metal Distribution Characteristics and Health Risk between Cultured and Wild Fish Captured from Honghu City, China

Honghu Lake, which listed in the “Ramsar Convention”, is the seventh largest freshwater lake in China and is regarded as one of the biggest freshwater product output areas in China. The toxic element distribution in cultured and wild fish and the corresponding health risks through fish consumption from Honghu area were investigated. The mean concentration in the muscle of cultured and wild fish (Carassius auratus and Ctenopharyngodon idellus) decreased in the order: Zn (18.94) > Cu (0.8489) > Cr (0.2840) > Pb (0.2052) and Zn (16.30) > Cr (1.947) > Cu (0.4166) > Pb (0.0525) > Cd (0.0060) (mean; mg/kg, wet weight). Scales (Multi factor pollution index (MPI) = 3.342) and the liver (MPI = 1.276) were regarded as the main accumulation tissues for cultured fish, and the bladder (MPI = 0.640) and intestine (MPI = 0.477) were regarded as the main accumulation tissues for wild fish. There were no obvious health risks associated with the consumption of cultured and wild fish based on the calculated results of the target hazard quotient (THQ), carcinogenic risk (CR), and estimated weekly intake (EWI). Pb and Cr were recognized as the major health risk contributors for inhabitants through wild and cultured fish consumption. Cultured fish had a greater health risk than wild fish based on the calculation results of THQ and CR. Muscle consumption resulted in more health risks than mixed edible tissues for cultured fish, but for wild fish, the conclusion was the opposite. Mixed fish (cultured:wild = 1:1) muscle consumption had relatively lower risks than the consumption of cultured or wild fish muscle separately. Consuming no more than 465 g/day (wet wt) of cultured fish muscle, 68 g/day (wet wt) of wild fish muscle, 452 g/day (wet wt) of mixed cultured fish edible tissues or 186 g/day (wet wt) of mixed wild fish edible tissues from the Honghu area can assure human health.

Heavy metals and metalloid distribution in different organs and health risk assessment for edible tissues of fish captured from Honghu Lake

Honghu Lake is the seventh largest freshwater lake in China, and fishery is one of the most important economic sources for local inhabitants. Toxic metal concentrations in muscle of all analyzed fish species captured from Honghu Lake were generally below China standards, except Cr in crucian carp. The average concentrations were decreased in the following order, Zn (14.65 mg/kg) > Cr (1.25 mg/kg) > Cu (0.5994 mg/kg) > Pb (0.0884 mg/kg) > Cd (0.0069 mg/kg) > As (0.0007 mg/kg). There was no significant health risk in consuming fish captured from Honghu Lake, based on the analysis results of target hazard quotient (THQ), carcinogenic risk (CR), and estimated weekly intake (EWI). Mixed edible fish tissues consuming brought higher carcinogenic risks than muscle consuming. Pb was regarded as the major contributor of potential non-carcinogenic risk, while As of the potential carcinogenic risk. THQ set the most stringent allowed values of the average consuming amount of fish muscle at 1,316 g/d, while CR set the value of mixed fish tissues at 525 g/d.

Efficiency Evaluation on the Application of Internet Plus in College Teaching Based on Analytic Hierarchy Process and Multiple Linear Regression

In the background of Internet Plus, the construction of digital campus has been constantly advanced. The traditional Higher-Education industry is seeking new breakthrough in the aspect of classroom teaching. According to the analysis of Network-based classroom status around the world and the survey of Zhongnan University of Economics and Law, this study proposed a new strategy that using the mobile Internet technology named Internet Plus into classroom to improve the quality of classroom teaching in order to design and implementation of “Synchronous E-test System”. Moreover, this study combined with the practice situations of the system, and used AHP method and multiple regression analysis to demonstrate the applicability and effectiveness of the system. Introduction Since Premier Li Keqiang put forward the concept of Internet Plus in the government work report in 2015, the major domestic traditional industries are seeking new breakthroughs actively in the context of this era, the Internet has become a driving engine that can make Chinese economy transforming and upgrading. The concept of Internet Plus has many features contains ubiquitous, open, equality, cooperation and free, it reconstructed the teaching and learning process and the impact caused bumpy and profound change of traditional Higher-Education through big data collection, reorganization and reutilization[1]. The Higher-Education Field which has kinds of resources and takes the responsibility of national innovation development can only grasp the opportunities so that can achieve further development. Digital campus construction has become much more completed in fundamental facilities, but the future direction of digital campus construction is facing new opportunities and challenges under the circumstance that mobile Internet has become a new normality. Numbers of teachers thought that the smart phone or other mobile terminal was a tenacious third party in class. However, it is undeniable that the students can obtain more information whenever and wherever they want through the mobile Internet. Recently, except for a few universities have been attempting a new mode called “turnover classroom”, most of the university classrooms maintain the traditional method “teaching and listening”. Classroom questioning was the mainly way of the teachers and students’ interaction. Teachers couldn’t have a global awareness about students’ knowledge reception and students lack feedback to teachers as well. How to use the rapid development of mobile Internet technology to bring new vitality to classroom education is the problem to be solved in Higher-Education Field. According to the problems in classroom combined with the survey results, this paper proposes a new form of the combination of mobile Internet and teaching that the teachers and students get

Efficiency evaluation of an Internet Plus University Student Affairs System based on fuzzy theory and the analytic hierarchy process

Internet Plus now has been widely applied to various societal aspects and areas of human life in China, including higher education. Student affairs management is necessary for the successful implementation of higher education management. The quality and overall standards of higher education management could be further enhanced through the integration of student affairs management with the Internet. Chinese colleges have already begun to promote the implementation of Internet Plus student affairs systems. Therefore, a set of universal and effective evaluation index mechanism for the comprehensive evaluation of the system efficiency of these applications could be used as valuable references for the further implementation of higher education management in China. In this article, a comprehensive evaluation model for the system efficiency of an Internet Plus student affairs system based on the universal behavior characteristics of Chinese school counsellors and students is developed using fuzzy mathematics and the analytic hierarchy process (AHP). Furthermore, the efficacy of the proposed evaluation model is verified using data collected from the Micro-Campus Information System at Zhongnan University of Economics and Law.

Causes Analysis on the Pollution of the South Lake in Wuhan City Based on Fault Tree Theory

South Lake, the second largest lake in Wuhan, has been polluted seriously in recent years. Unfortunately, specific reasons for the pollution phenomenon impose an insurmountable hurdle. To address this challenge, we used the fault tree theory as a effective tool to conduct comprehensive analysis of the pollution top events. Innovatively, on the basis of integrated area pollution status research, we initiated the qualitative and quantitative analyses of pollution reasons in South Lake. The results showed that there were three main causes leading to the water pollution in South Lake: the weakness of environmental awareness, the lack of government supervision, the frequent of sewage discharge. Notably, we suggested the optimal strategy to make efficient pollution management based on the priority of criticality, which including improving the environmental awareness of businesses and residents, enhancing the government supervision and reducing the discharge frequency. We summarized scientific and objective measures to control water pollution of the South Lake, and it provide a scientific and efficient method to prevent the deterioration of the urban lakes.