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Ecological network analysis for an industrial solid waste metabolism system
2019
Guan, Yuru | Huang, Guohe | Liu, Lirong | Huang, Charley Z. | Zhai, Mengyu
Faced with an increasing amount of industrial solid waste (ISW) in the process of rapid industrialization, it is indispensable to carry out ISW metabolism study to realize source and waste reduction. In this study, a new composite waste input-output (WIO) model is developed to examine ISW production and production relationships among different sectors. In particular, the extended methods of network control analysis and network utility analysis are used in the ecological network analysis under two ISW scenarios (i.e. common industrial solid waste (CISW) and hazardous waste (HW) scenarios). Furthermore, comprehensive utilization analysis is first developed to evaluate the ISW utilization level and to guide the planning of sectors with large proportion of ISW production. A case study of Guangdong, China shows that indirect flow analysis can be used to understand the internal ISW metabolism structure. The mining sectors produce a large amount of direct ISW and perform a low level of comprehensive utilization, but they have mutualism relationships with other sectors. The energy transformation (EH) sector in the CISW system has high direct generation intensity and plays as a main controller. The situation of paper manufacturing (MP) sector in HW system is similar to that of EH. Therefore, it is expected that the results of this study will provide scientific foundations for these sectors to formulate future ISW reduction policies.
显示更多 [+] 显示较少 [-]Evaluation on the stabilization of Zn/Ni/Cu in spinel forms: Low-cost red mud as an effective precursor
2019
Su, Minhua | Liao, Chang-Zhong | Ma, Shengshou | Zhang, Kuibao | Tang, Jinfeng | Liu, Chengshuai | Shih, Kaimin
Red mud, which is from the aluminum industry, is a potentially under-utilized resource. Technological processes for using low-cost red mud as an alternative precursor for detoxifying metal pollutants urgently need to be developed. In this study, we systematically investigated the feasibility of using red mud to detoxify metal-containing wastes (e.g., fly ash) via the formation of preferable crystalline phases. To understand the mechanism of metal detoxification by red mud, CuO, NiO, and ZnO were blended with red mud at different weight ratios and the mixtures were then subjected to ceramic-sintering. After sintering, the X-ray diffraction results revealed that all of the metals (i.e., Cu, Ni, and Zn) were able to be crystallographically incorporated into spinel lattices. Sintering the red mud at 1100 °C for 3 h effectively converted the metals into spinels. The mixing weight ratios strongly affected the efficiency of the metal incorporation. The red mud was able to incorporate 15 wt% of metal oxides. The incorporation mechanisms mainly occurred between the metal oxide(s) and hematite. Modified TCLP tests were conducted to further evaluate the metal stabilization performance of the red mud, which demonstrated the leachabilities of ZnO and the sintered red mud + ZnO product. The concentration of leached metal was substantially reduced after the incorporation process, thus demonstrating that red mud can be successfully used to detoxify metals. The results of this study reveal that waste red mud can be feasibly reused as a promising waste-to-resource strategy for stabilizing heavy metal wastes.
显示更多 [+] 显示较少 [-]Suspended particles potentially enhance nitrous oxide (N2O) emissions in the oxic estuarine waters of eutrophic lakes: Field and experimental evidence
2019
Zhou, Yiwen | Xu, Xiaoguang | Han, Ruiming | Li, Lu | Feng, Yu | Yeerken, Senbati | Kang, Song | Wang, Qilin
Estuaries are considered hot spots for the production and emissions of nitrous oxide (N2O) and easily occur suspended particles (SPS), however, current understanding about the role of SPS in the N2O emissions from the oxic estuarine waters of lacustrine ecosystems is still limited. In this study, field investigations were performed in the estuaries of hypereutrophic Taihu Lake, and laboratory simulations were simultaneously conducted to ascertain the characteristics of N2O emissions with different SPS concentrations. The results showed that the N2O emission fluxes ranged from 9.75 to 118.38 μg m−2 h−1, indicating a high spatial heterogeneity for the N2O emissions from the estuaries of Taihu Lake. Although the dissolved oxygen (DO) concentrations were up to 7.85 mg L−1 in the estuarine waters, from where the N2O emissions fluxes were approximately three times that of the lake regions. Multiple regression model selected the total nitrogen (TN), SPS, and DO concentrations as the crucial factors influencing the N2O emission fluxes. Particularly for SPS, the simulation results showed that the N2O concentrations increased gradually with the increase in the SPS concentrations of an oxic water column containing 4 mg L−1 of NO3−-N, indicating that a high SPS concentration can accelerate the N2O emissions. It was related to the change of denitrifying bacteria population in the SPS, as evidenced by its significantly positive correlation with N2O emissions (p < 0.01). Our findings will draw attentions to the role of SPS playing in the N2O productions and emissions in eutrophic lakes, and its effect on nitrogen cycle should be considered in the future study.
显示更多 [+] 显示较少 [-]Occurrence of swampy/septic odor and possible odorants in source and finished drinking water of major cities across China
2019
Wang, Chunmiao | Yu, Jianwei | Guo, Qingyuan | Sun, Daolin | Su, Ming | An, Wei | Zhang, Yu | Yang, Min
Swampy/septic odors are one of the most important odor types in drinking water. However, few studies have specifically focused on it compared to the extensive reported musty/earthy odor problems, even though the former is much more offensive. In this study, an investigation covering the odor characteristics, algal distribution and possible odorants contributing to swampy/septic odor, including dimethyl disulfide (DMDS), dimethyl trisulfide (DMTS), diisopropyl sulfide (DIPS), dipropyl sulfide (DPS), dibutyl sulfide (DBS), 2-methylisoborneol (2-MIB) and geosmin (GSM), was performed in source and finished water of 56 drinking water treatment plants (DWTPs) in 31 cities across China. While the musty/earthy and swampy/septic odors were dominant odor descriptors, the river source water exhibited a higher proportion of swampy/septic odor (38.5%) compared to much higher detection rate of musty/earthy odor (50.0%) in the lake/reservoir source water. The occurrence of swampy/septic odor, which was much easier to remove by conventional drinking water treatment processes compared to musty/earthy odors, was decreased by 62.9% and 46.3% in river and lake/reservoir source water respectively. Statistical analysis showed that thioethers might be responsible for the swampy/septic odor in source water (R2 = 0.75, p < 0.05). Specifically, two thioethers, DMDS and DMTS were detected, and other thioethers were not found in all water samples. DMDS was predominant with a maximum odor activity value (OAV) of 2.0 in source water and 1.3 in finished water. The distribution of the thioethers exhibited a marked regional characteristics with higher concentrations being detected in the east and south parts of China. The high concentrations of thioethers in lake/reservoir source water samples could be partly interpreted as the bloom of the cyanobacteria. This study provides basic information for swampy/septic odor occurrence in drinking water and will be helpful for further water quality management in water industry in China.
显示更多 [+] 显示较少 [-]Distribution, metabolism and metabolic disturbances of alpha-cypermethrin in embryo development, chick growth and adult hens
2019
Liu, Xueke | Liu, Chang | Wang, Peng | Liang, Yiran | Zhan, Jing | Zhou, Zhiqiang | Liu, Donghui
Alpha-cypermethrin (Alpha-CP), an important pyrethroid pesticide, has been widely used for pest control in agriculture and parasite control in livestock farms. Thus, alpha-CP is easily exposed to wild birds and poultry, which may pose a potential risk to birds. Alpha-CP and its metabolites have been detected in many environmental samples, including poultry and wild birds. We studied the distribution and metabolism of alpha-CP and its metabolites in embryo development and newborn chick. The results showed that metabolites were the main residual forms of alpha-CP in different stages of life and might increase the exposure risk of bird and its offspring. Metabolomics investigation of newborn chick exhibited that the metabolic profiles of chicks were disturbed, especially lipid metabolism. The concentrations of cis-DCCA and trans-DCCA were high in the first and second weeks of chick growth, indicating that chicks have limited ability to further metabolize and excrete cis-DCCA and trans-DCCA during the early stages of chicks. Toxicokinetics of alpha-CP in adult hens showed that alpha-CP was rapidly metabolized to acid metabolites, which could be further metabolized and excreted. The results about metabolism of alpha-CP in different stages of chicken indicate that the ability of the embryo and early chick to metabolize alpha-CP and its metabolites was the weakest. Therefore, it is of important significance to focus on evaluating the ecological risk of cypermethrin on birds at different stages of life cycle.
显示更多 [+] 显示较少 [-]Effects of perinatal exposure to BPA, BPF and BPAF on liver function in male mouse offspring involving in oxidative damage and metabolic disorder
2019
Meng, Zhiyuan | Tian, Sinuo | Yan, Jin | Jia, Ming | Yan, Sen | Li, Ruisheng | Zhang, Renke | Zhu, Wentao | Zhou, Zhiqiang
Bisphenols (BPs) are common environmental pollutants that are ubiquitous in the natural environment and can affect human health. In this study, we explored the effects of perinatal exposure to BPA, BPF and BPAF on liver function involving in oxidative damage and metabolic disorders in male mouse offspring. We found that BPA exposure impairs the antioxidant defense system, increases lipid peroxidation, and causes oxidative damage in the liver. Furthermore, the levels of 13 metabolites were significantly altered following BPA exposure. We found that BPF exposure significantly increased the expression and activity of CAT, suggesting disturbances in the antioxidant defense system. Moreover, BPF exposure led to metabolic disorders in the liver due to changes in the levels of 8 key metabolites. Exposure to BPAF caused no negative effects on oxidative damage, but altered the levels of β-glucose and glycogen. In summary, perinatal exposure to BPA, BPF and BPAF differentially influence oxidative damage and metabolic disorders in the livers of male mouse offspring. The impact of early life exposure to BPs now warrants future investigations.
显示更多 [+] 显示较少 [-]Vertical profiles and distributions of aqueous endocrine-disrupting chemicals in different matrices from the Pearl River Delta and the influence of environmental factors
2019
Gong, Jian | Ran, Yong | Zhang, Dainan | Chen, Diyun | Li, Haiyan | Huang, Youda
The occurrence and distributions of selected endocrine-disrupting chemicals (EDCs), along with related environmental factors, were investigated in two rivers and six reservoirs in the Pearl River Delta. The vertical profiles of aqueous 4-tert-octylphenol (OP), 4-nonylphenol (NP), and estrone (E1) were constant, with little change in concentration between the surface and the river bottom, while higher aqueous concentrations of bisphenol A (BPA) were found in the bottom layers of the rivers. OP and NP in suspended particulate matter (SPM) were transferred from the surface to the bed layer, ultimately accumulating in the sediment. However, the particulate profiles of BPA and E1 both featured increases from the surface to the bottom layers and attenuation in the river bed. Dissolved oxygen (DO), water temperature, and pH were negatively correlated with the EDC concentrations, and negative relationships between DO and distribution coefficient (Kd) values for OP and NP were found as well. This indicated that these environmental parameters were primarily responsible for the EDC vertical distribution and SPM-water partitioning in the rivers. Positive relationships were observed between chlorophyll a and EDCs in the particulate phase, and the algae/water Kd values for EDCs in reservoirs were comparable to the SPM/water and sediment/water Kd values from the rivers. These results suggest that algae played an important role in regulating the distribution of EDCs in surface waters. Moreover, relationships between UV absorbance and EDCs revealed that π-π interactions were among the dissolved organic carbon (DOC)-EDC binding mechanisms and that DOC fractions with higher degrees of aromaticity and humification possessed higher affinities towards EDCs.
显示更多 [+] 显示较少 [-]Effect of colloids on non-Fickian transport of strontium in sediments elucidated by continuous-time random walk analysis
2019
Liu, Dong-Xu | Zuo, Rui | Jivkov, Andrey P. | Wang, Jin-Sheng | Hu, Li-Tang | Huang, Liu-Xing
Understanding the influence of colloids on radionuclide migration is of significance to evaluate environmental risks for radioactive waste disposals. In order to formulate an appropriate modelling framework that can quantify and interpret the anomalous transport of Strontium (Sr) in the absence and presence of colloids, the continuous time random walk (CTRW) approach is implemented in this work using available experimental information. The results show that the transport of Sr and its recovery are enhanced in the presence of colloids. The causes can be largely attributed to the trap-release processes, e.g. electrostatic interactions of Sr, colloids and natural sediments, and differences in pore structures, which gave rise to the varying interstitial velocities of dissolved and, if any, colloid-associated Sr. Good agreement between the CTRW simulations and the column-scale observations is demonstrated. Regardless of the presence of colloids, the CTRW modelling captures the characteristics of non-Fickian anomalous transport (0 < β < 2) of Sr. In particular, a range of 0 < β < 1, corresponding to the cases with greater recoveries, reveal strongly non-Fickian transport with distinctive earlier arrivals and tailing effects, likely due to the physicochemical heterogeneities, i.e. the repulsive interactions and/or the macro-pores originating from local heterogeneities. The results imply that colloids can increase the Sr transport as a barrier of Sr sorption onto sediments herein, apart from often being carriers of sored radionuclides in aqueous phase. From a modelling perspective, the findings show that the established CTRW model is valid for quantifying the non-Fickian and promoted transport of Sr with colloids.
显示更多 [+] 显示较少 [-]Soil physiochemical properties and landscape patterns control trace metal contamination at the urban-rural interface in southern China
2019
Li, Cheng | Sun, Ge | Wu, Zhifeng | Zhong, Honglin | Wang, Rongping | Liu, Xiaonan | Guo, Zhixing | Cheng, Jiong
This study examined the influences of three subsets of environmental factors (i.e. soil physicochemical properties including pH, organic matters and soil texture, landscape patterns, and parent materials) on the spatial variations and sources of soil trace metal contamination across an urban-rural environmental gradient in Guangzhou City, southern China. We collected 318 surface soil samples from forests, orchards, farmlands, and urban lawns using a random tessellation design for selecting sample sites. The geo-accumulation indices showed that 18%–88% of soil samples were contaminated: moderate to high contamination with Cd and Hg, low to moderate contamination with Cu, Pb, Zn and Ni, and low contamination with As and Cr. However, less than 13% of soil samples were considered to have exceeded the national standards causing environmental and human health concerns. The mean geo-accumulation indices increased in the order of forest, paddy field/orchard, vegetable, road/residential, and park/residential areas for As, Cd, Ni, Pb, Zn, closely following a land disturbance gradient. Spearman Correlation and Cluster Analyses showed that Pb-Cu-Zn had traffic-related origins, Cd-Hg were mainly influenced by fertilization or industrial emissions, and As-Cr-Ni had geogenic origins for agricultural soils. In contrast, the Ni, Hg and Cd contamination sources for urban soils included both anthropogenic and geogenic origins. The Stepwise Regression and Partial Redundancy Analyses showed that three subsets of environmental factors explained 43%–87% of variations of soil contamination for both agricultural and urban soils. We concluded that soil contamination was mainly controlled by soil physiochemical properties followed by landscape patterns. Soil absorption of aerial loads of trace metal pollutants dominated the soil contamination processes. Our findings implied that improving soil physiochemical properties and landscape designs can strengthen environmental buffering and carrying capacity, thus alleviating soil contamination and reducing non-point-source pollution in the study region.
显示更多 [+] 显示较少 [-]Tris(1,3-dichloro-2-propyl) phosphate accelerated the aging process induced by the 4-hydroxynon-2-enal response to reactive oxidative species in Caenorhabditis elegans
2019
Wang, Chen | An, Jing | Bai, Yingchen | Li, Hui | Chen, Haibo | Ou, Dong | Liu, Yongdi
Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) has been frequently detected in environmental media and biological samples. However, knowledge of its adverse health consequences is limited. In the current study, Caenorhabditis elegans (C. elegans, L1 larvae) were exposed to TDCPP at environmentally relevant concentrations (control, 0.1, 1, 100 and 1000 μg L⁻¹) for 72 h to explore any association between TDCPP and the aging process. Some of the degenerative age-related indicators were observed, including locomotion behaviors and lifespan. As crucial biomarkers of aging, the accumulation of lipofuscin, and lipid peroxidation (LPO) products exemplified by 4-hydroxynon-2-enal (4-HNE) were detected. This product forms as a result of oxidative stress, as confirmed by an N-acetyl-L-cysteine (NAC) pharmacological assay. Moreover, a significant increase in reactive oxide species (ROS) production in a dose-dependent manner using a fluorescent probe was observed. For the underlying molecular mechanism of the above aging phenotypes, significantly upregulated transcription of genes related to antioxidant systems, especially a subset of glutathione S-transferase (gst-5, gst-6, gst-9, gst-10, gst-19, gst-24, gst-26, gst-29, gst-33, and gst-38), was found by RNA-Seq and further confirmed by RT-qPCR. The elevated glutathione S-transferase (GST) was attributed to the significant increase in 4-HNE because mutations in gst-5 and gst-24 inhibited the conjugation of GSTs with 4-HNE. Therefore, GST play an indispensable role in the detoxification process of TDCPP exposure and further confirmed LPO accumulation at the molecular mechanism level. In conclusion, TDCPP accelerated the aging process induced by the LPO products, 4-HNE, response to reactive oxidative species in C. elegans.
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