Toward a robust analytical method for separating trace levels of nano-materials in natural waters: cloud point extraction of nano-copper(II) oxide

Cloud point extraction (CPE) factors, namely Triton X-114 (TX-114) concentration, pH, ionic strength, incubation time, and temperature, were optimized for the separation of nano-sized copper(II) oxide (nCuO) in aqueous matrices. The kinetics of phase transfer was studied using UV–visible spectroscopy. From the highest separation rate, the most favorable conditions were observed with 0.2 %?w/v of TX-114, pH?=?9.0, ionic strength of 10 mM NaCl, and incubation at 40 °C for 60 min, yielding an extraction efficiency of 89.2?±?3.9 % and a preconcentration factor of 86. The aggregate size distribution confirmed the formation of very large nCuO–micelle assemblies (11.9 μm) under these conditions. The surface charge of nCuO was also diminished effectively. An extraction efficiency of 91 % was achieved with a mixture of TX-100 and TX-114 containing 30 wt.% of TX-100. Natural organic and particulate matters, represented by humic acid (30 mg/L) and micron-sized silica particles (50 mg/L), respectively, did not significantly reduce the CPE efficiency (<10 %). The recovery of copper(II) ions (20 mg/L) in the presence of humic acid was low (3–10 %). The spiked natural water samples were analyzed either directly or after CPE by inductively coupled plasma mass spectrometry following acid digestion/microwave irradiation. The results indicated the influence of matrix effects and their reduction by CPE. A delay between spiking nCuO and CPE may also influence the recovery of nCuO due to aggregation and dissolution. A detection limit of 0.04 μg Cu/L was achieved for nCuO.     

Another avenue of action: an examination of climate change countermovement industries’ use of PAC donations and their relationship to Congressional voting over time

The political mobilization of American business elites in the 1970s and 1980s has been well studied by political scientists. Environmental sociologists have explored how industries in this elite countermovement have organized to prevent environmental legislation. The literature often focuses on the efforts of this movement to shape public opinion on climate change. However, political scientists argue business elites are running several parallel strategies simultaneously in order to protect their interests. FEC data are utilized in multilevel logit models to examine how donations from industrial Political Action Committees (PACs) relate to Congressional representative’s environmental voting behavior over a 20-year period. Industries associated with the environmental countermovement have increasingly used PAC donations over time, and every additional $10,000 a representative received from countermovement industries significantly decreased odds of their taking the pro-environmental stance even when controlling for representatives’ demographics, districts, Congressional polarization and time-period.     

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.     

Threats to intact tropical peatlands and opportunities for their conservation

Large, intact areas of tropical peatland are highly threatened at a global scale by the expansion of commercial agriculture and other forms of economic development. Conserving peatlands on a landscape scale, with their hydrology intact, is of international conservation importance to preserve their distinctive biodiversity and ecosystem services and maintain their resilience to future environmental change. We explored threats to and opportunities for conserving remaining intact tropical peatlands; thus, we excluded peatlands of Indonesia and Malaysia, where extensive deforestation, drainage, and conversion to plantations means conservation in this region can protect only small fragments of the original ecosystem. We focused on a case study, the Pastaza‐Marañón Foreland Basin (PMFB) in Peru, which is among the largest known intact tropical peatland landscapes in the world and is representative of peatland vulnerability. Maintenance of the hydrological conditions critical for carbon storage and ecosystem function of peatlands is, in the PMFB, primarily threatened by expansion of commercial agriculture linked to new transport infrastructure that is facilitating access to remote areas. There remain opportunities in the PMFB and elsewhere to develop alternative, more sustainable land‐use practices. Although some of the peatlands in the PMFB fall within existing legally protected areas, this protection does not include the most carbon‐dense (domed pole forest) areas. New carbon‐based conservation instruments (e.g., REDD+, Green Climate Fund), developing markets for sustainable peatland products, transferring land title to local communities, and expanding protected areas offer pathways to increased protection for intact tropical peatlands in Amazonia and elsewhere, such as those in New Guinea and Central Africa which remain, for the moment, broadly beyond the frontier of commercial development.     

Aerosol speciation and mass prediction from toluene oxidation under high NOx conditions

A kinetically based gas-particle partitioning box model is used to highlight the importance of parameter representation in the prediction of secondary organic aerosol (SOA) formation following the photo-oxidation of toluene. The model is initialized using experimental data from York University's indoor smog chamber and provides a prediction of the total aerosol yield and speciation. A series of model sensitivity experiments were performed to study the aerosol speciation and mass prediction under high NO_x conditions (VOC/NO_x = 0.2). Sensitivity experiments indicate vapour pressure estimation to be a large area of weakness in predicting aerosol mass, creating an average total error range of 70 μg m^?3 (range of 5–145 μg m^?3), using two different estimation methods. Aerosol speciation proved relatively insensitive to changes in vapour pressure. One species, 3-methyl-6-nitro-catechol, dominated the aerosol phase regardless of the vapour pressure parameterization used and comprised 73–88% of the aerosol by mass. The dominance is associated with the large concentration of 3-methyl-6-nitro-catechol in the gas-phase. The high NO_x initial conditions of this study suggests that the predominance of 3-methyl-6-nitro-catechol likely results from the cresol-forming branch in the Master Chemical Mechanism taking a significant role in secondary organic aerosol formation under high NO_x conditions. Further research into the yields and speciation leading to this reaction product is recommended.     

Use of ATP Readings to Predict a Successful Hygiene Intervention in the Workplace to Reduce the Spread of Viruses on Fomites

The purpose of this study was to validate the use of adenosine triphosphate (ATP) for evaluating hygiene intervention effectiveness in reducing viral dissemination in an office environment. The bacterial virus MS-2 was used to evaluate two scenarios, one where the hand of an individual was contaminated and another where a fomite was contaminated. MS-2 was selected as a model because its shape and size are similar to many human pathogenic viruses. Two separate experiments were conducted, one in which the entrance door push plate was inoculated and the other in which the hand of one selected employee was inoculated. In both scenarios, 54 selected surfaces in the office were tested to assess the dissemination of the virus within the office. Associated surface contamination was also measured employing an ATP meter. More than half of the tested hands and surfaces in the office were contaminated with MS-2 within 4 h. Next, an intervention was conducted, and each scenario was repeated. Half of the participating employees were provided hand sanitizer, facial tissues, and disinfecting wipes, and were instructed in their use. A significant (p < 0.05) reduction was observed in the number of surfaces contaminated with virus. This reduction in viral spread was evident from the results of both viral culture and the surface ATP measurements, although there was no direct correlation between ATP measurements with respect to viral concentration. Although ATP does not measure viruses, these results demonstrate that ATP measurements could be useful for evaluating the effectiveness of hygiene interventions aimed at preventing viral spread in the workplace.     

海洋环境中光合色素分析方法研究与应用进展

根据国内外的文献,综述了海洋环境中光合色素分析方法的发展状况,指出了其分析方法在发展过程中创新的主要方面,并对光合色素分析在赤潮监测、藻类的化学分类及生物碳生物量和矿物质通量方面的应用进行了展望。     

改性氢氧化镁制备及其去除地下水中Cr3+性能研究

氢氧化镁作为一种可缓慢释放OH-的碱,能使多数重金属离子转换为沉淀,而且不会引起太大的pH变化.但氢氧化镁难溶于水,在含水层中的迁移能力很差.若要用于地下水重金属污染修复,需要对氢氧化镁进行改性.因此,本文利用表面活性剂对氢氧化镁粉末进行改性,合成了氢氧化镁胶体,并对改性氢氧化镁的稳定性、粒度及其对Cr3+的稳定化效果进行了分析.结果表明,复配表面活性剂改性的氢氧化镁悬浮液稳定性好,粒径小,0.6~8.4μm的颗粒占82.41%.利用改性氢氧化镁对Cr3+污染地下水进行处理,其对Cr3+的去除机理主要为沉淀反应,氢氧化镁和Cr3+反应的质量比约为1.333∶1,氢氧化镁和初始Cr3+浓度对Cr3+的去除效果都有较大的影响.     

Myrothecium verrucaria NF-08产漆酶条件的响应面法优化及粗酶染料脱色研究

以半知菌属疣孢漆斑菌Myrothecium verrucaria NF-08为供试菌,采用响应面方法优化菌株产漆酶条件,并以其漆酶粗酶进行3种结构类型6种染料的脱色试验,考察了粗酶浓度、温度和p H值对脱色率的影响.两水平析因设计、中心组合设计和验证试验结果表明:葡萄糖浓度为15.4 g·L~(-1)、蛋白胨浓度为43.3 g·L~(-1)和培养基初始p H值为6.68时,漆酶活性达到最大值(25.58±1.60)U·m L~(-1),是单因素试验(16.82 U·m L~(-1))的1.52倍,提高了52.1%.以上述发酵条件获得的M.verrucaria NF-08漆酶粗酶对3种结构类型染料均有脱色效果,排序为偶氮类优于芳甲烷类优于蒽醌类.脱色率随粗酶浓度增大(2~8 U·m L~(-1))、反应温度升高(15~35℃)而上升,随p H值上升(4~10)而下降.粗酶浓度为5 U·m L~(-1),反应温度为25℃,p H值为4时,偶氮类染料铬黑T和芳甲烷类染料碱性品红即可几乎完全脱色,脱色率分别为99.2%和94.6%.     

Distributions of radionuclide sorption coefficients (Kd) in sub-surface sediments and the implications for transport calculations

The effect of the spatial variability of K_d on calculations of contaminant travel time in the vadose zone was determined. Depth discrete measurements of K_d were made for a suite of radionuclides (¹⁰⁹Cd, ⁵⁷Co, ⁶⁰Co, ⁸⁵Sr, ¹³⁷Cs, and ⁸⁸Y) utilizing a sediment core from the E-Area at the Savannah River Site. The K_d’s were ordered as ⁸⁵Sr²⁺ < ¹³⁷Cs⁺ < ¹⁰⁹Cd²⁺ < ⁵⁷Co²⁺ = ⁶⁰Co²⁺ << ⁸⁸Y³⁺ and the values generally fell below or near the lowest quartile of values reported in the literature. Correlations were generally weak between soil properties and K_d values. Most importantly, all of the K_d distributions could be reasonably approximated as log-normal. Deterministic and stochastic calculations of contaminant travel time to the water table were made. The deterministic calculations were based on each of three conceptual models of the vadose zone: complete stratification (17 strata, each with a different K_d), two strata (two sections of the vadose zone, each characterized by a single, average K_d), and unstratified (a single zone with an average K_d). Stochastic calculations were based on log-normal fits to the K_d data. The two strata model generally yielded travel times 2× greater than those in the completely stratified model. The unstratified model yielded travel times that were between 3 and 5 times greater than the completely stratified model. The stochastic mean travel times were comparable to those of the two strata model.