Village-scale reserves in the forest frontier regions of Chenes and Calakmul,Mexico

ABSTRACT

Sketch-map-facilitated interviews were conducted in 23 villages in two adjacent regions in the southern Yucatan Peninsula of Mexico – the Maya (and increasingly Mennonite) forest-agriculture mosaic of the Chenes, and the late-20^th-century-settlement forest frontier of Calakmul – to determine the frequency and typology of local-scale reserves, including the external (e.g. Payments for Environmental Services programs) and internal sources of their generation. 9% of the study communities are found to satisfy the author’s criteria for deliberate, autochthonous reserves. The static polygon reserve and static map are found to have limited value for understanding the evolving cultural ecologies of these regions. Alternative approaches are discussed, particularly those employed by geographers.     

Determination of 27 pharmaceuticals and personal care products (PPCPs) in water: The benefit of isotope dilution

• Isotope dilution method was developed for the determination of 27 PPCPs in water. • The established method was successfully applied to different types of water samples. • The correction effect of corresponding 27 ILSs over 70 d was investigated. • Benefit of isotopic dilution method was illustrated for three examples. Pharmaceuticals and personal care products (PPCPs) are a unique group of emerging and non-persistent contaminants. In this study, 27 PPCPs in various water samples were extracted by solid phase extraction (SPE), and determined by isotope dilution method using liquid chromatography coupled to tandem triple quadruple mass spectrometer (LC-MS/MS). A total of 27 isotopically labeled standards (ILSs) were applied to correct the concentration of PPCPs in spiked ultrapure water, drinking water, river, effluent and influent sewage. The corrected recoveries were 73%–122% with the relative standard deviation (RSD)<16%, except for acetaminophen. The matrix effect for all kinds of water samples was<22% and the method quantitation limits (MQLs) were 0.45–8.6 ng/L. The developed method was successfully applied on environmental water samples. The SPE extracts of spiked ultrapure water, drinking water, river and wastewater effluent were stored for 70 days, and the ILSs-corrected recoveries of 27 PPCPs were obtained to evaluate the correction ability of ILSs in the presence of variety interferences. The recoveries of 27 PPCPs over 70 days were within the scope of 72%–140% with the recovery variation<37% in all cases. The isotope dilution method seems to be of benefit when the extract has to be stored for long time before the instrument analysis.     

Biological conversion pathways of sulfate reduction ammonium oxidation in anammox consortia

• The SRAO phenomena tended to occur only under certain conditions. • High amount of biomass and non-anaerobic condition is requirement for SRAO. • Anammox bacteria cannot oxidize ammonium with sulfate as electron acceptor. • AOB and AnAOB are mainly responsible for ammonium conversion. • Heterotrophic sulfate reduction mainly contributed to sulfate conversion. For over two decades, sulfate reduction with ammonium oxidation (SRAO) had been reported from laboratory experiments. SRAO was considered an autotrophic process mediated by anammox bacteria, in which ammonium as electron donor was oxidized by the electron acceptor sulfate. This process had been attributed to observed transformations of nitrogenous and sulfurous compounds in natural environments. Results obtained differed largely for the conversion mole ratios (ammonium/sulfate), and even the intermediate and final products of sulfate reduction. Thus, the hypothesis of biological conversion pathways of ammonium and sulfate in anammox consortia is implausible. In this study, continuous reactor experiments (with working volume of 3.8L) and batch tests were conducted under normal anaerobic (0.2≤DO<0.5 mg/L) / strict anaerobic (DO<0.2 mg/L) conditions with different biomass proportions to verify the SRAO phenomena and identify possible pathways behind substrate conversion. Key findings were that SRAO occurred only in cases of high amounts of inoculant biomass under normal anaerobic condition, while absent under strict anaerobic conditions for same anammox consortia. Mass balance and stoichiometry were checked based on experimental results and the thermodynamics proposed by previous studies were critically discussed. Thus anammox bacteria do not possess the ability to oxidize ammonium with sulfate as electron acceptor and the assumed SRAO could, in fact, be a combination of aerobic ammonium oxidation, anammox and heterotrophic sulfate reduction processes.     

Enhanced debromination of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) by zero-valent zinc with ascorbic acid

• Highly efficient debromination of BDE-47 was achieved in the ZVZ/AA system. • BDE-47 debromination by the ZVZ/AA can be applied to a wide range of pH. • AA inhibits the formation of (hydr)oxide and accelerates the corrosion of ZVZ. • Reduction mechanism of BDE-47 debromination by the ZVZ/AA system was proposed. A new technique of zero-valent zinc coupled with ascorbic acid (ZVZ/AA) was developed and applied to debrominate the 2,2′,4,4′-Tetrabromodiphenyl ether (BDE-47), which achieved high conversion and rapid debromination of BDE-47 to less- or non-toxic forms. The reaction conditions were optimized by the addition of 100 mg/L ZVZ particles and 3 mmol/L AA at original solution pH= 4.00 using the solvent of methanol/H₂O (v:v= 4:6), which could convert approximately 94% of 5 mg/L BDE-47 into lower-brominated diphenyl ethers within a 90 min at the ZVZ/AA system. The high debromination of BDE-47 was mainly attributed to the effect of AA that inhibits the formation of Zn(II)(hydr)oxide passivation layers and promotes the corrosion of ZVZ, which leads to increase the reactivity of ZVZ. Additionally, ion chromatography and gas chromatography mass spectrometry analyses revealed that bromine ion and lower-debromination diphenyl ethers formed during the reduction of BDE-47. Furthermore, based on the generation of the intermediates products, and its concentration changes over time, it was proposed that the dominant pathway for conversion of BDE-47 was sequential debromination and the final products were diphenyl ethers. These results suggested that the ZVZ/AA system has the potential for highly efficient debromination of BDE-47 from wastewater.     

肥煤自燃全过程热动力学特征参数研究

实验测定了林西矿肥煤样品30~900℃煤自燃全过程热动力学特征参数,得出:TG/DTG曲线显示煤样DTG初始临界温度45℃,干裂温度122℃,活性温度195℃,增速温度265℃,质量极大值温度342℃,着火温度465℃,最大热失重速率温度515℃和燃尽温度690℃;DSC曲线显示,煤样初始放热温度60℃、最大热释放速率温度511℃。结合TG-DTG-DSC曲线综合分析可知,煤温达到510℃左右时煤样反应最剧烈。由煤自燃标志气体测定实验系统得出:煤温130℃后CO,CO 2释放量迅速增加,210℃增加速度下降;CH 4,C 2 H 6含量变化具有规律性且两者变化相近;C 2 H 4出现温度为130℃;C 2 H 4/C 2 H 6比值在190~350℃有较强的规律性,呈上升趋势且上升速度较快;350℃之后,CH 4,C 2 H 6,C 2 H 4体积分数均开始急剧增大;C 2 H 4/CO与C 2 H 4/CO 2变化趋势大致相同,在130~350℃时缓慢增长,达到350℃后比值呈指数形式上升。经拟合曲线,得到活化能的3个突变点温度:70,180,220℃,其中180℃与交叉点温度相吻合。通过以上研究,得到了肥煤自燃全过程的热力学特征参数,为实际生产中防治煤自燃提供了理论依据。     

大型碳化硅生产园区面源源强及减排指标核算

以某年产25万吨大型碳化硅园区无组织排放面源为例,提出基于多个地面站气象数据的CALPUFF模型地面浓度反推方法,优化流场模拟,使得无组织面源源强核算结果更加准确,并以环境保护目标空气质量达标为原则,核算其大气污染物减排指标,得出具体结论:园区大气污染物SO2、NOX、CO、PM10年排放量分别为449.06t、86.98t、5158.58t、115.06t;无组织排放SO2、CO及PM10的减排比例分别为63.5%、19.2%、42.44%,对应减排量分别为285.16 t/a、990.45 t/a、48.83 t/a。     

饮用水源微生物快速检测技术的发展及应用

微生物是威胁饮用水安全的首要问题，水环境微生物快速检测技术的开发和应用是推动饮用水源微生物快速检测和水质安全预警技术发展的保障。随着对水质微生物污染快速检测和准确预警新要求的提出，水环境中微生物在线检测和预警技术得到了越来越多的开发和应用。笔者总结了水环境常见微生物检测方法和技术的发展，重点讨论了饮用水源微生物快速检测技术的发展和应用，根据各项技术的应用和推广使用程度，将其归纳为常用快速检测技术、潜在适用快速检测技术和新型快速检测技术等类别，并详细阐述了一些应用较广的技术，以期为构建水质微生物污染早期预警系统提供参考。     

“竞争申请制”:可持续发展政策试点与央地关系重构

可持续发展目标(SDGs)的提出,开启了人类可持续发展领域最宏大的政策实验,也为开展国际视野的比较公共政策研究提供了难得机遇。执行SDGs及国家可持续发展政策需要处理好中央政府与地方政府间关系,而政策试点是协调这一关系的重要政策工具。已有文献对经济政策试点做了较充分的研究,然而对旨在实现经济、社会与环境协调的可持续发展政策试点,现有研究尚缺乏成型理论。在复杂央地关系格局下,对于需持续投入成本且成果难以界定的可持续发展政策试点,其具有怎样的不同于经济政策试点的机制?此外,众多西方学者将美国作为政策试点研究的制度基础并视其为“民主实验室”。然而,政策试点在以中国为代表的不同体制国家中同样存在,并以多样的机制发挥作用。那么,不同国家体制内的可持续发展政策试点又有哪些异同?政策试点影响下中国既有的央地关系发生了怎样的重构?对此,本文基于最典型案例原则,选取中国与美国响应SDGs分别开展的政策试点进行比较研究。笔者识别了不同体制下试点机制的异同,指出中国基于“竞争申请制”开展的可持续发展政策试点强化了中央部委与地方政府间关系,形成了地方官员的可持续发展激励,保障了政策试点的实施。     

Emergency shutdown of fluidized bed reaction systems

With several industrial applications of fluidized bed technology recently commercialized worldwide, it becomes essential to develop safe operation methods for fluidized bed reaction systems (FBRSs) to prevent any influence on their process values, which lead to accidents. To preventing any disaster or malfunction in an FBRS, an emergency shutdown system (ESD) is initiated, closing the reaction system in case of any abnormality by effectively isolating the flammable gas. However, an ESD is also prone to the “inactivation problem,” in which in the case of failure it initiates the emergency shutdown, even when the operating conditions of the reaction system are abnormal. It is also vulnerable to a “malfunction problem,” where the emergency shutdown is performed even when the operating conditions of the reaction system are normal. In this study, these problems were solved by investigating a reaction system through the monitoring of appropriate parameters and setting up of trigger levels, which reflect the uniqueness of an FBRS using an ESD. The parameters were identified by analyzing the scenario leading to an accident. The trigger levels were determined as the points at which the loss is smaller in the presence of an ESD, as compared to the value of the loss function in the presence or absence of an ESD. Furthermore, the ESD design model was applied as a case study in the ammoxidation process of propylene. The results showed that an ESD can prevent an approximately 8 billion yen of loss due to accidents in plant operations, against an investment of 200 million yen.     

桂林市城区大气VOCs污染特征及对O3和SOA的生成潜势

对桂林市城区大气中挥发性有机物(VOCs)的污染特征,以及VOCs对臭氧(O3)和二次有机气溶胶(SOA)的生成潜势进行了研究。结果显示,研究期间,共检出VOCs物种78种,平均体积分数为21.32×10-9,表现为芳香烃(67.82%)烷烃(19.56%)卤代烃(7.50%)烯烃(2.86%)含氧挥发性有机物(1.41%)。VOCs体积分数空间分布呈现市中心和下风向郊区两个高值区。通过苯与甲苯的浓度比值发现,林科所VOCs主要来自交通源和生物源,师专甲山校区VOCs主要是来自交通源,其余测点VOCs主要来自交通源、工业源和外来传输源。分析乙苯和间/对二甲苯的浓度比值发现,电子科大尧山校区气团光化学年龄较大,光化学反应活性相对较强烈;旅游学院、华侨旅游经开区、大埠中心校气团光化学年龄较小,光化学反应活性相对较弱。VOCs对O3生成潜势最大的为芳香烃(93.81%),其次是烷烃(7.22%)和烯烃(4.75%);对SOA生成潜势最大的为芳香烃(97.45%),其次是烷烃(2.55%)。