Application of a level IV fugacity model to simulate the long-term fate of hexachlorocyclohexane isomers in the lower reach of Yellow River basin, China

A level IV multimedia fugacity model was established to simulate the fate and transfer of hexachlorocyclohexane (HCH) isomers in the lower reach of the Yellow River basin, China, during 1952-2010. The predicted concentrations of HCHs are in good agreement with the observed ones, as indicated by the residual errors being generally lower than 0.5 logarithmic units. The effects of extensive agricultural application and subsequent prohibition of HCHs are reflected by the temporal variation of HCHs predicted by the model. It is predicted that only 1.8 tons of HCHs will be left in 2010, less than 0.06% of the highest contents (in 1983) in the study area, and about 99% of HCHs remain in soil. The proportions of HCH isomers in the environment also changed with time due to their different physicochemical properties. Although beta-HCH is not the main component of the technical HCHs, it has become the most abundant isomer in the environment because of its persistence. The dominant transfer processes between the adjacent compartments were deposition from air to soil, air diffusion through the air-water interface and runoff from soil to water. Sensitivity analysis showed that degradation rate in soil, parameters related to major sources, and thickness of soils had the strongest influence on the model result. Results of Monte Carlo simulation indicated the overall uncertainty of model predictions, and the coefficients of variation of the estimated concentrations of HCHs in all the compartments ranged from 0.5 to 5.8.     

低有机碳含量表层土中Fe2O3对γ-666光解的催化作用

考察5种低有机碳含量天然土中Fe₂O₃光催化降解γ-666的光解动力学,γ-666的光解符合准一级动力学方程.从所得的γ-666光解动力学常数可知,随Fe₂O₃质量分数从0.40%增加到5.40%,γ-666的一级光解动力学常数也增大,且两者的线性相关系数为0.952,其在5种天然土中的半衰期随Fe₂O₃含量的增加依次为133.3h,82.5h,44.1h,28.5h,20.4h.由此可见,低有机碳含量天然土中Fe₂O₃对γ-666的光解具有明显的催化作用.     

生物过滤法处理含氨废气研究

研究了生物过滤法处理含氨废气的技术，实验中考察了气体的停留时间、进气方式、进气中氨浓度等因素对氨法除率的影响，当进气中氨的浓度分别为１５．２、７５．９和１５．２０ｍｇ（ＮＨ３）／ｍ＾３时，生物过滤反应器对氨的去除均在９５％以上，反应时间是３２ｓ，处理后的气体中氨的浓度可以达到国家一级排放标准，对填料中各形态氮浓度的分析证明氨在反应器中的转化以硝化反应为主。     

Humic acids decrease the photodegradation of the sunscreen UV filter 2-phenylbenzimidazole-5-sulfonic acid in natural waters

The sunscreen UV filter 2-phenylbenzimidazole-5-sulfonic acid (PBSA) is an emerging pollutant recently detected in surface waters. PBSA is photolabile in pure water and sunscreen cream. PBSA photoinduces DNA damages. However, the photochemical behavior and environmental persistence of PBSA are not well known. Here, we studied the photochemical transformation of PBSA in sea and continental waters. Results show that photodegradation is dependent on water constituents. Whereas low concentrations of humic acids accelerate PBSA photodegradation slightly, high concentrations of humic acids inhibit the photodegradation. Colloidal organic matters of high molecular weights are the main water constituents inhibiting photodegradation. The estimated solar photolytic half-life of PBSA at environmental concentration levels ranged from 3?days from June to August to 35?days in December. Findings show that PBSA is not persistent in waters that are low in colloidal organic matters.     

Detecting antibiotic resistance genes and human potential pathogenic Bacteria in fishmeal by culture-independent method

Environmental Science and Pollution Research - Fishmeal is a fundamental ingredient of feedstuffs and is used globally in aquaculture. However, there are few data on the antibiotic resistance genes...     

Preparation and uranium (VI) biosorption for tri-amidoxime modified marine fungus material

Environmental Science and Pollution Research - The preparation, characterization, and uranium (VI) adsorption properties of tri-amidoxime modified marine fungus material (ZZF51-GPTS-EDA-AM/ZGEA)...     

Frontal crash simulations using parametric human models representing a diverse population

Abstract

Objective: Analyses of crash data have shown that older, obese, and/or female occupants have a higher risk of injury in frontal crashes compared to the rest of the population. The objective of this study was to use parametric finite element (FE) human models to assess the increased injury risks and identify safety concerns for these vulnerable populations.

Methods: We sampled 100 occupants based on age, sex, stature, and body mass index (BMI) to span a wide range of the U.S. adult population. The target anatomical geometry for each of the 100 models was predicted by the statistical geometry models for the rib cage, pelvis, femur, tibia, and external body surface developed previously. A regional landmark-based mesh morphing method was used to morph the Global Human Body Models Consortium (GHBMC) M50-OS model into the target geometries. The morphed human models were then positioned in a validated generic vehicle driver compartment model using a statistical driving posture model. Frontal crash simulations based on U.S. New Car Assessment Program (U.S. NCAP) were conducted. Body region injury risks were calculated based on the risk curves used in the US NCAP, except that scaling was used for the neck, chest, and knee–thigh–hip injury risk curves based on the sizes of the bony structures in the corresponding body regions. Age effects were also considered for predicting chest injury risk.

Results: The simulations demonstrated that driver stature and body shape affect occupant interactions with the restraints and consequently affect occupant kinematics and injury risks in severe frontal crashes. U-shaped relations between occupant stature/weight and head injury risk were observed. Chest injury risk was strongly affected by age and sex, with older female occupants having the highest risk. A strong correlation was also observed between BMI and knee–thigh–hip injury risk, whereas none of the occupant parameters meaningfully affected neck injury risks.

Conclusions: This study is the first to use a large set of diverse FE human models to investigate the combined effects of age, sex, stature, and BMI on injury risks in frontal crashes. The study demonstrated that parametric human models can effectively predict the injury trends for the population and may now be used to optimize restraint systems for people who are not similar in size and shape to the available anthropomorphic test devices (ATDs). New restraints that adapt to occupant age, sex, stature, and body shape may improve crash safety for all occupants.     

基于低碳经济视角的环境资源会计的探析

随着低碳经济的发展,人们意识到环境问题日益严重,尤其作为企业,如何更好地履行社会责任需重点关注。低碳经济不仅影响企业的经济活动,而且使企业的会计核算面临更大的挑战。与传统的会计相比,环境资源会计在加强环境资源管理、促进低碳经济发展方面起到至关重要的作用。然而中国目前还没有构建完善的环境资源会计理论体系来指导相关工作。基于低碳经济视角的环境资源会计核算分析了环境资源会计的内涵、核算对象、目标、确认、计量和信息披露,形成了核算框架,为环境资源会计的具体实施提供参考。     

Enhanced removal of Cr(Ⅵ) by biochar with Fe as electron shuttles

Biochar is extensively used as an effective soil amendment for environmental remediation.In addition to its strong contaminant sorption capability, biochar also plays an important role in chemical transformation of contaminant due to its inherent redox-active moieties.However, the transformation efficiency of inorganic contaminants is generally very limited when the direct adsorption of contaminants on biochar is inefficient. The present study demonstrates the role of Fe ion as an electron shuttle to enhance Cr(Ⅵ) reduction by biochars. Batch experiments were conducted to examine the effects of Fe(Ⅲ) levels,pyrolysis temperature of biochar, initial solution pH, and biochar dosage on the efficiency of Cr(Ⅵ) removal. Results showed a significant enhancement in Cr(Ⅵ) reduction with an increase in Fe(Ⅲ) concentration and a decrease of initial pH. Biochar produced at higher pyrolysis temperatures(e.g., 700°C) favored Cr(Ⅵ) removal, especially in the presence of Fe(Ⅲ), while a higher biochar dosage proved unfavorable likely due to the agglomeration or precipitation of biochar. Speciation analysis of Fe and Cr elements on the surface of biochar and in the solution further confirmed the role of Fe ion as an electron shuttle between biochar and Cr(Ⅵ). The present findings provide a potential strategy for the advanced treatment of Cr(Ⅵ) at low concentrations as well as an insight into the environmental fate of Cr(Ⅵ) and other micro-pollutants in soil or aqueous compartments containing Fe and natural or engineered carbonaceous materials.     

长白山区沟谷乌拉苔草(Carex. meyeriana)沼泽湿地水文物理效应

通过对长白山区沟谷乌拉苔草(C.meyeriana)沼泽湿地和三江平原乌拉苔草沼泽湿地土壤物理性质和乌拉苔草根系生物量的测定,对水文物理效应进行了分析,结果表明:长白山区沟谷乌拉苔草沼泽湿地的土壤孔隙度小于三江平原乌拉苔草沼泽湿地,容重和体积质量则高于三江平原乌拉苔草沼泽湿地。土壤蓄水能力低于三江平原乌拉苔草沼泽湿地;乌拉苔草发达的根系具有强大的蓄水能力,尤以根鞘的蓄水能力最强,蓄水可以占鲜质量的91.1%~93.72%,比根系蓄水能力高出2.54%~33.94%。由此得知乌拉苔草沼泽湿地的具有巨大的蓄水能力,是天然的水调节器。通过分析可知其水文物理过程对沼泽湿地对其上游河流具有调节作用,同时还可以保存上游河流生物多样性,以及严重的影响着水面以下化学过程的发生。