Adsorption of Ca2+ on single layer graphene oxide

Graphene oxide(GO) holds great promise for a broad array of applications in many fields,but also poses serious potential risks to human health and the environment.In this study,the adsorptive properties of GO toward Ca~(2+) and Na+were investigated using batch adsorption experiments,zeta potential measurements,and spectroscopic analysis.When pH increased from 4 to 9,Ca~(2+)adsorption by GO and the zeta potential of GO increased significantly.Raman spectra suggest that Ca~(2+)was strongly adsorbed on the GO via –COO Ca~+ formation.On the other hand,Na+was adsorbed into the electrical diffuse layer as an inert counterion to increase the diffuse layer zeta potential.While the GO suspension became unstable with increasing pH from 4 to 10 in the presence of Ca~(2+),it was more stable at higher pH in the NaC l solution.The findings of this research provide insights in the adsorption of Ca~(2+)on GO and fundamental basis for prediction of its effect on the colloidal stability of GO in the environment.     

Estimation of bioaccessibility and potential human health risk of mercury in Chinese patent medicines

Mercury(Hg), mainly in cinnabar species, has been used in medicine for thousands of years in China, and worldwide concern has been raised on its toxicity. In this work, the amount of bioaccessible mercury in 16 Chinese patent medicines(CPMs) was measured by using an in vitro simulated digestion system, consisting of simulated gastric and intestinal fluid, to investigate the bioavailability of mercury in CPMs and evaluate its potential risk to human health. Total mercury and mercury in the gastrointestinal extracts were measured by inductively coupled plasma mass spectrometry(ICP-MS). The levels of total Hg in 16 CPMs ranged from not detected to 11.89 mg/g, with a mean value of 1.13 mg/g, while the extractable Hg ranged from not detected to 4.37 μg/g, with a mean value of 0.42 μg/g.Mercury bioaccessibility varied significantly in the investigated CPMs, depending on the ingredient. Compared to the CPMs without cinnabar(2.5%–30.9%), the percentage of mercury in the gastrointestinal supernatants for CPMs with cinnabar was quite a bit lower(0.037%). By comparing with the Food and Agricultural Organization/World Health Organization Joint Expert Committee on Food Additives(FAO/WHO) safety guideline, the average daily intake dose(ADD) of Hg in the medicines was then calculated to access the risk of mercury to human health from taking CPMs.     

Removal of tetracycline from aqueous solution by a Fe3O4 incorporated PAN electrospun nanofiber mat

Pollution of antibiotics, a type of emerging contaminant, has become an issue of concern,due to their overuse in human and veterinary application, persistence in environment and great potential risk to human and animal health even at trace level. In this work, a novel adsorbent, Fe3O4 incorporated polyacrylonitrile nanofiber mat(Fe-NFM), was successfully fabricated via electrospinning and solvothermal method, targeting to remove tetracycline(TC), a typical class of antibiotics, from aqueous solution. Field emission scanning electron microscopy and X-ray diffraction spectroscopy were used to characterize the surface morphology and crystal structure of the Fe-NFM, and demonstrated that Fe-NFM was composed of continuous, randomly distributed uniform nanofibers with surface coating of Fe3O4 nanoparticles. A series of adsorption experiments were carried out to evaluate the removal efficiency of TC by the Fe-NFM. The pseudo-second-order kinetics model fitted better with the experimental data. The highest adsorption capacity was observed at initial solution p H 4 while relative high adsorption performance was obtained from initial solution p H 4 to 10. The adsorption of TC on Fe-NFM was a combination effect of both electrostatic interaction and complexation between TC and Fe-NFM. Freundlich isotherm model could better describe the adsorption isotherm. The maximum adsorption capacity calculated from Langmuir isotherm model was 315.31 mg/g. Compared to conventional nanoparticle adsorbents which have difficulties in downstream separation, the novel nanofiber mat can be simply installed as a modular compartment and easily separated from the aqueous medium, promising its huge potential in drinking and wastewater treatment for micro-pollutant removal.     

A review on completing arsenic biogeochemical cycle：Microbial volatilization of arsines in environment

Arsenic （As） is ubiquitous in the environment in the carcinogenic inorganic forms, posing risks to human health in many parts of the world. Many microorganisms have evolved a series of mechanisms to cope with inorganic arsenic in their growth media such as transforming As compounds into volatile derivatives. Bio-volatilization of As has been suggested to play an important role in global As biogeochemical cycling, and can also be explored as a potential method for arsenic bioremediation. This review aims to provide an overview of the quality and quantity of As volatilization by fungi, bacteria, microalga and protozoans. Arsenic bio-volatilization is influenced by both biotic and abiotic factors that can be manipulated/elucidated for the purpose of As bioremediation. Since As bio- volatilization is a resurgent topic for both biogeochemistry and environmental health, our review serves as a concept paper for future research directions.     

Determination of the effective density and fractal dimension of PM emissions from an aircraft auxiliary power unit

Gas turbine particulate matter (PM) emissions contribute to air quality degradation and are dangerous to both human health and the environment. Currently, PM mass concentrations determined from gravimetric measurements are the default parameter for gas turbine emissions compliance with PM regulations. The measurement of particle size however, is of significant interest due to its specific effects on health and climate science. The mass concentration can be determined from the number-size distribution measurement but requires the experimental evaluation of effective density of a number of particles to establish the power-law relationship. In this study, the effective density of PM emissions from an aircraft Auxiliary Power Unit (APU) with petroleum diesel, conventional aviation fuel (Jet A-1) and a multicomponent surrogate fuel (Banner NP 1014) as combusting fuels have been compared. An experimental configuration consisting of a Differential Mobility Analyzer, a Centrifugal Particle Mass Analyzer and a Condensation Particle Counter (DMA-CPMA-CPC) was deployed for this purpose. Overall, a decrease in the effective density (220–1900 km? 3) with an increase in the particle size was observed and found to depend on the engine operating condition and the type of fuel undergoing combustion. There was a change in the trend of the effective densities between the PM emissions generated from the fuels burnt and the engine operating conditions with increasing particle size.     

Primary neuronal-astrocytic co-culture platform for neurotoxicity assessment of di-(2-ethylhexyl) phthalate

Plastics such as polyvinyl chlorides （PVC） are widely used in many indoor constructed environments; however, their unbound chemicals, such as di-（2-ethylhexyl） phthalates （DEHP）, can leach into the surrounding environment. This study focused on DEHP＇s effect on the central nervous system by determining the precise DEHP content in mice brain tissue after exposure to the chemical, to evaluate the specific exposure range. Primary neuronal-astrocyte co-culture systems were used as in vitro models for chemical hazard identification of DEHP. Oxidative stress was hypothesized as a probable mechanism involved, and therefore the total reactive oxygen species （ROS） concentration was determined as a biomarker of oxidative stress. In addition, NeuriteTracer, a neurite tracing plugin with ImageJ, was used to develop an assay for neurotoxicity to provide quantitative measurements of neurological parameters, such as neuronal number, neuron count and neurite length, all of which could indicate neurotoxic effects. The results showed that with 1 nmol/L DEHP exposure, there was a significant increase in ROS concentrations, indicating that the neuronal-astrocyte cultures were injured due to exposure to DEHP. In response, astrocyte proliferation （gliosis） was initiated, serving as a mechanism to maintain a homeostatic environment for neurons and protect neurons from toxic chemicals. There is a need to assess the cumulative effects of DEHP in animals to evaluate the possible uotake and effects on the human neuronal system from exoosure to DEHP in the indoor environment.     

Distribution and mode of occurrence of uranium in bottom ash derived from high-germanium coals

The radioactivity of uranium in radioactive coal bottom ash(CBA) may be a potential danger to the ambient environment and human health. Concerning the limited research on the distribution and mode of occurrence of uranium in CBA, we herein report our investigations into this topic using a number of techniques including a five-step Tessier sequential extraction, hydrogen fluoride(HF) leaching, Siroquant(Rietveld) quantification, magnetic separation, and electron probe microanalysis(EPMA). The Tessier sequential extraction showed that the uranium in the residual and Fe–Mn oxide fractions was dominant(59.1%and 34.9%, respectively). The former was mainly incorporated into aluminosilicates,retained with glass and cristobalite, whereas the latter was especially enriched in the magnetic fraction, of which about 50% was present with magnetite(Fe_3O_4) and the rest in other iron oxides. In addition, the uranium in the magnetic fraction was 2.6 times that in the non-magnetic fraction. The experimental findings in this work may be important for establishing an effective strategy to reduce radioactivity from CBA for the protection of our local environment.     

Antimony speciation in the environment: Recent advances in understanding the biogeochemical processes and ecological effects

Antimony(Sb) is a toxic metalloid, and its pollution has become a global environmental problem as a result of its extensive use and corresponding Sb-mining activities. The toxicity and mobility of Sb strongly depend on its chemical speciation. In this review, we summarize the current knowledge on the biogeochemical processes(including emission, distribution,speciation, redox, metabolism and toxicity) that trigger the mobilization and transformation of Sb from pollution sources to the surrounding environment. Natural phenomena such as weathering, biological activity and volcanic activity, together with anthropogenic inputs, are responsible for the emission of Sb into the environment. Sb emitted in the environment can adsorb and undergo redox reactions on organic or inorganic environmental media, thus changing its existing form and exerting toxic effects on the ecosystem. This review is based on a careful and systematic collection of the latest papers during 2010–2017 and our research results, and it illustrates the fate and ecological effects of Sb in the environment.     

Cobalt and manganese stress in the microalga Pavlova viridis （Prymnesiophyceae）： Effects on lipid peroxidation and antioxidant enzymes

Pollution of marine environment has become an issue of major concern in recent years.Serious environmental pollution by heavy metals results from their increasing utilization in industrial processes and because most heavy metals are transported into the marine environment and accumulated without decomposition.The aim of the present study is to investigate the effects on growth,pigments, lipid peroxidation,and some antioxidant enzyme activities of marine microalga Pavlova viridis,in response to elevated concentrations of cobalt(Co)and manganese(Mn),especially with regard to the involvement of antioxidative defences against heavy metal-induced oxidative stress.In response to Co~(2 ),lipid peroxidation was enhanced compared to the control,as an indication of the oxidative damage caused by metal concentration assayed in the microalgal cells but not Mn~(2 ).Exposure of Pavlova viridis to the two metals caused changes in enzyme activities in a different manner,depending on the metal assayed:after Co~(2 )treatments,total superoxide dismutase(SOD)activity was irregular,although it was not significantly affected by Mn~(2 )exposure.Co~(2 )and Mn~(2 )stimulated the activities of catalase(CAT)and glutathione(GSH),whereas,ghitathione peroxidase(GPX)showed a remarkable increase in activity in response to Co~(2 )treatments and decreased gradually with Mn~(2 )concentration,up to 50μmol/L,and then rose very rapidly,reaching to about 38.98% at 200μmol/L Mn~(2 ).These results suggest that an activation of some antioxidant enzymes was enhanced,to counteract the oxidative stress induced by the two metals at higher concentration.     

关于对烟花爆竹行业开征环境税问题探讨研究

如今燃放烟花爆竹所带来的环境问题已经日益明显,特别是对环境空气质量的影响。在当今雾霾笼罩的大氛围下,对烟花爆竹的生产和销售、消费领域采取适当环境经济手段来调控(如征收环境税)就显得很有必要,这在一定程度上可以控制烟花爆竹的消费量,减少燃放烟花爆竹所造成的环境外部性。同时用征收来的环境税对研发采用环保药剂、先进技术的企业进行补贴、奖励,或者对于这些企业给予一定的环境税优惠,可以引导烟花爆竹产业朝着更加健康的方向发展。     

《控制船舶有害防污底系统国际公约》及有关问题探讨

介绍了《控制船舶有害防污底系统国际公约》产生的历史背景和基本内容，论述了中国加入该公约的必要性及对中国产生的影响，并提出中国加入控制船舶有害防污底系统国际公约后对策和建议。     

液化石油气推广应用的可行性研究

城市交通带来的大气污染问题日趋严重，为解决这一问题，国内外科研人员进行了数十年的开发研究，液化石油替代传统燃料作为机动车动力源已被认为是解决城市机动车尾气污染行之有效的办法，该方法集环保、经济、安全等优点，是未来汽车工业发展的方向。本文针对目前我国城市大气污染现状，分析比较现有防治对策措施，对液化气汽车在国内推广应用的可行性进行了简单阐述。     

废水脱盐处理技术研究进展

综述了废水脱盐处理的工艺、特点及各自所发挥的功能,重点介绍了膜处理技术的发展与特点、控制膜污染的预防措施与对策, 展望了废水脱盐处理技术的发展方向.     

海水养殖对生物多样性的影响研究进展

近年来,海水养殖对全球海水产品供应的贡献持续增加,但是海水养殖对海洋和沿海生物多样性以及海洋资源可持续利用产生的不利影响,已经引起国内外海洋、环境等领域科学家和大众的广泛关注.海水养殖对生物多样性的影响一般包括在海岸带地区建设养殖场对海域或土地生物多样性的影响,对为维持养殖生产活动所需的超量海域的生物多样性的影响,海水养殖残饵、代谢物污染及养殖生物外逃对海洋生态系生物多样性的影响等方面.本文首先综述了上述影响,并展望了我国海水养殖业生物多样性保护的管理对策,以期为海水养殖业可持续发展、海洋资源可持续利用和生物多样性保护提供参考.     

黄土高原南部土壤退化机理研究

黄土高原土壤侵蚀极其严重 ,这不仅导致了土壤生产力的降低 ,同时也导致了土壤的退化。本文在定位监测、室内分析及野外调查的基础上 ,研究了黄土高原南部土壤的退化机理。结果表明 :土壤中 <0 0 1mm颗粒和土壤养分流失是造成黄土高原土壤退化的主要原因 ,耕地土壤结构状况的恶化和土壤酶的流失使土壤退化程度进一步加剧 ,从而成为严重制约该区经济发展障碍。     

基于AHP-模糊综合评价的LNG接收站安全评价

介绍了一种基于层次分析法和模糊综合评价的LNG接收站的安全评价方法,根据LNG接收站工艺、环境等特点,建立LNG接收站安全评价指标,根据评价指标间的关系构造指标的判断矩阵,求出对应指标系统的权重,对指标进行评价。根据对国内某接收站的安全评价,提出相应的整改措施。     

论环境监测技术的发展

环境监测是为经济发展和环境管理服务的。只有监测技术先进,数据准确可靠,才能有效地为管理和决策服务。本人在煤矿工作多年,调查研究发现,一些环境监测技术方面的问题需要改进和完善,如在环境监测分析过程中,大量的化学试剂、洗涤液等污染物质排入环境。为使环境监测既能提供准确可靠的监测数据,又不使实验室成为污染源,这是一个亟待解决的问题。     

影响赤潮的气象因素分析

以 1 998年 7～ 1 0月辽东湾海域赤潮为例 ,分析了气象因素对赤潮全过程的影响。分析表明 :气温、降水、光照、风速等气象因素与赤潮的发生、发展和消亡有密切的关系 ,气象条件是诱发赤潮的关键因素。在温度适宜的情况下 ,降水量的多少对赤潮的发生、发展有关键的作用。最后探讨了利用气象因素与赤潮的关系进行赤潮发生、发展的气象潜势预报的基本思路