菲和镉单一及复合污染条件下在毛蚶体内的富集动力学研究

采用室内半静态双箱动力学模型实验,研究了菲和镉单一及复合污染条件下在毛蚶(Anadara subcrenata)体内的生物富集,通过对富集与释放过程中毛蚶体内菲和Cd的富集量进行非线性曲线拟合,获得了菲和Cd单一及复合污染条件下在毛蚶体内的吸收速率常数k1、释放速率常数k2、生物富集因子BCF、生物半衰期B1/2和平衡状态下最大富集量CA max等动力学参数。实验结果表明,菲和Cd在实验前期富集速率较高,8 d以后富集速率减缓,释放阶段与富集阶段相似。毛蚶对菲的BCF值为37.80,远大于Cd的BCF值13.12,且生物半衰期时间更长,菲更容易在生物体内富集。菲和Cd联合暴露条件下,在毛蚶体内的CA max和BCF值均大于单一作用,说明二者同时暴露时,毛蚶对菲和镉的吸收富集均有所增强。实验模型拟合度较好,输出值和实测值之间无显著性差异,拟合方程和拟合参数可信。     

CdIn2S4/复合材料的制备及光降解罗丹明B

利用高压静电纺丝技术,制得含有羧基的导电聚合物纤维(聚偏氟乙烯/苯乙烯-马来酸酐共聚物/纳米石墨),高温水热条件下在纤维表面制备CdIn2S4颗粒,得到CdIn2S4/导电聚合物纤维复合材料。运用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、紫外-可见吸收光谱仪(UV-Vis)和热失重分析仪(TGA)对复合材料的结构进行表征。并利用350 W氙灯模拟太阳光进行光催化降解罗丹明B。结果发现,CdIn2S4/导电聚合物纤维复合材料的降解效率高于CdIn2S4粉体和Degussa P25 TiO2粉体,光催化降解3 h,罗丹明B的降解率为96.2%。     

Analysis of ecotoxic influence of waste from the biomass gasification process

Environmental Science and Pollution Research - The purpose of this research was evaluation of the effect of soil contamination with waste coming from biomass gasification on chosen indicators of...     

Histopathological changes in zebrafish embryos exposed to DLPCBs extract from Zhanjiang coastal sediment

Dioxin-like polychlorinated biphenyls (DLPCBs) are ubiquitous persistent pollutants that cause adverse effects in many environmental organisms. DLPCBs in marine sediments can be absorbed by benthic organisms, bioaccumulate, and biomagnify through the food chain and threaten animal and human health. There are no reports of DLPCBs concentrations in the Zhanjiang Gulf seabed. This study was designed to investigate the concentration of DLPCBs in the Zhanjiang coastal sediment and histopathological changes in zebrafish (Diano rerio) embryos exposed to environmentally relevant concentrations of DLPCBs. Of the five sites selected, two sites TS and JSW contained DLPCBs at concentrations of 0.08 and 22.54 ng/g dry sediment, respectively. Two groups of zebrafish embryos were used. One group was exposed to 3.75, 7.5, 15, 30, and 60 mg/ml of DLPCBs extracted from the sediments sampled from the TS site and the second group to 4.375, 8.75, 17.5, 35, and 70 mg/ml of DLPCBs from JSW site from 0.75 h post-fertilization (hpf) to 96 hpf. The zebrafish exposed to 60 and 70 mg/ml of DLPCBs at 96 hpf displayed gross histopathological changes with cardiac lesions including pericardial edema being the most deleterious. Other changes observed were hydropic degeneration of gill filaments and hepatocytes, loss of intestinal folds, and uninflated swim bladder. It appears that only a few sites of the Zhanjiang gulf are contaminated with DLPCBs. This is the first report of histopathological changes in the gills, hepatocytes, intestines, heart, and the swim bladder in zebrafish embryos exposed to DLPCBs from a coastal sediment. Further studies with sampling at different stages of development are required to identify which organ/tissue is most sensitive to DLPCBs.     

Influence of filtration velocity on DON variation in BAF for micropolluted surface water treatment

Biological aerated filters (BAFs) are widely used for the treatment of micropolluted surface water. However, the biological process produces dissolved organic nitrogen (DON), which, as precursors of nitrogenous disinfection by-products, pose potential threats to drinking water safety. Therefore, to control DON in BAF effluent, it is necessary to study the influence of BAF operation parameters on DON production. In this study, the influence of filtration velocity in a BAF on DON production was investigated. Under different filtration velocity (0.5, 2, and 4 m/h) conditions, profiles of DON concentrations along the media layer were measured. The profile at a filtration velocity of 0.5 m/h showed a decreasing trend, and the ones under filtration velocities of 2 and 4 m/h fluctuated in a small range (from 0.1 to 0.4 mg/L). Moreover, the relatively high filtration velocities of 2 and 4 m/h resulted in a lower level of DON concentration. Additionally, 3D excitation-emission matrix fluorescence spectroscopy was used to characterize DON. It is found that the patterns of DON at a relatively high filtration velocity condition (4 m/h) were obviously different from the ones under low filtration velocity conditions (0.5 and 2 m/h).     

Identifying resource and environmental carrying capacity in the Yangtze River Economic Belt,China: the perspectives of spatial differences and sustainable development

Environment, Development and Sustainability - The resource and environmental carrying capacity (RECC) is an important foundation and support for a city or region, and determines the direction of...     

Optimal Policy Mechanism Design for Cross-Sector and Multi-Stage Pollution Control with a Bilevel Model: Application to SO<Subscript>2</Subscript> Emission in China

In this paper, we construct a multi-stage coordinated programming model under tax system to control SO₂ emission. The model is based on an explicitly formulated SO₂ abatement cost function created under Chinese condition. Analysis of the effectiveness and impact on the economy of the model is carried out with consideration of game theory. By solving the model, theoretical results show that the volume-based multi-stage SO₂ tax system has two properties: effectiveness and equal-rate. Based on these theoretical results, empirical study is also performed using Chinese historical data. Compared with yearly single-stage programming model, the tax rate generated by the coordinated multi-stage programming model is time-invariant and rather moderate in scale. The total abatement cost among planning years in our model is 21.03 % less than the actual number and 6.68 % less than that in the single-stage situation. The tax payment suggested by our model is 10.62 % less than by the single-stage model. In general, a coordinated multi-stage programming model helps reduce the overall costs of environmental protection while achieving the same emission control target with less burden added to the economy.     

Research status,challenges and future prospects of renewable synthetic fuel catalysts for CO2 photocatalytic reduction conversion

Environmental Science and Pollution Research - In recent years, with global climate change, the utilization of carbon dioxide as a resource has become an important goal of human society to achieve...     

Carbon Sequestration Function of Check-Dams: A Case Study of the Loess Plateau in China

Check-dams are the most common structures for controlling soil erosion in the Loess Plateau. However, the effect of check-dams on carbon sequestration, along with sediment transport and deposition, has not been assessed over large areas. In this study, we evaluated the carbon sequestration function of check-dams in the Loess Plateau. The results indicate that there were approximately 11 000 check-dams distributed in the Loess Plateau, with an estimate of the amount of sediment of 21 × 10⁹ m³ and a soil organic carbon storage amount of 0.945 Pg. Our study reveals that check-dams in the Loess Plateau not only conserve soil and water but also sequester carbon.     

Effects of pig manure containing copper and zinc on microbial community assessed via phospholipids in soils

Pig manure (PM) is widely used as an organic fertilizer to increase yields of crops. Excessive application of compost containing relatively great concentrations of copper (Cu) and zinc (Zn) can change soil quality. To clarify the effects of different rates of application and to determine the optimal rate of fertilization, PM containing 1,115 mg Cu kg^?1, dry mass (dm) and 1,497 mg Zn kg^?1, dm was applied to alkaline soil at rates of 0, 11, 22, 44, 88, and 222 g PM kg^?1, dm. Phospholipid fatty acids (PLFAs) were used to assess soil microbial community composition. Application of PM resulted in greater concentrations of total nitrogen (TN), NH₄ ⁺-N, NO₃ ^?-N, total carbon (TC), soil organic matter (SOM) but lesser pH values. Soils with application rates of 88–222 g PM kg^?1, dm had concentrations of total and EDTA-extractable Cu and Zn significantly greater than those in soil without PM, and concentrations of T-Cu and T-Zn in these amended soils exceeded maximum limits set by standards in china. Except in the soil with a rate of 11 g PM kg^?1, dm, total bacterial and fungal PLFAs were directly proportional to rate of application of PM. Biomasses of bacteria and fungi were significantly greater in soils with application rates of 44–222 g PM kg^?1, dm than in the soil without PM. SOM, TC and EDTA-Zn had the most direct influence on soil microbial communities. To improve fertility of soils and maintain quality of soil, rate of application should be 22–44 g PM kg^?1 dm, soil containing Cu and Zn.