Uptake and leaching of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine by hybrid poplar trees

The feasibility of remediating a high explosive, octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), using hybrid poplar trees (Populus deltoides x nigra, DN34) was investigated. The fate, transport, and toxicity were determined. HMX was taken up by poplar cuttings from hydroponic solutions in long-term experiments (65 days) without evidence of toxicity. HMX was not toxic to actively growing hybrid poplar cuttings, even under saturated conditions. The measured log Kow for HMX was 0.19, less than other explosives, TNT, and RDX. However, the calculated transpiration stream concentration factor (TSCF) and root concentration factor (RCF) for HMX from an uptake study using radiolabeled [U-14C]HMX were 0.21 +/- 0.07 and 5.55 +/- 1.78 mL/g, respectively, both of which were intermediate between the values for TNT and ROX in previous reports. A 70% uptake of [U-14C]HMX was translocated and accumulated in leaves, and no metabolites were observed during a 65-day exposure using radiochromatography of plant tissue extracts. Most of the accumulated HMX (57%) in dried (fallen) poplar leaves was leached by deionized water after 5 days. Bioaccumulation in poplar trees and resolublization of HMX from leaves would be of significant ecological concern, and phytoremediation may not be warranted as a treatment option unless other processes occur under field conditions that degrade HMX to innocuous end products (e.g., photolysis, hydrolysis, or microbial degradation).     

Enantioselective biotransformation of chiral PCBs in whole poplar plants

Chiral PCBs have been used as molecular probes of biological metabolic processes due to their special physical, chemical, and biological properties. Many animal studies showed the enantioselective biotransformation of chiral PCBs, but it is unclear whether plants can enantioselectively biotransform chiral PCBs. In order to explore the enantioselectivity of chiral PCBs in whole plants, poplars (Populus deltoides × nigra, DN34), a model plant with complete genomic sequence, were hydroponically exposed to 2,2',3,5',6-pentachlorobiphenyl (PCB95) and 2,2',3,3',6,6'-hexachlorobiphenyl (PCB136) for 20 days. PCB95 and PCB136 were shown to be absorbed, taken-up and translocated in whole poplars, and they were detected in various tissues of whole poplars. However, the enantioselectivity of poplar for PCB95 and PCB136 proved to be quite different. The first eluting enantiomer of PCB95 was enantioselectively removed in whole poplar, especially in the middle and bottom xylem. It was likely enantioselectively metabolized inside poplar tissues, in contrast to racemic mixtures of PCB95 remaining in hydroponic solutions in contact with plant roots of whole and dead poplars. Unlike PCB95, PCB136 remained nearly racemic in most parts of whole poplars after 20 days exposure. These results suggest that PCB136 is more difficult to be enantioslectively biotransformed than PCB95 in whole poplars. This is the first evidence of enantioselectivity of chiral PCBs in whole plants, and suggests that poplars can enantioselectively biotransform at least one chiral PCB.     

Sustainability science and engineering: the emergence of a new metadiscipline

A case is made for growth of a new metadiscipline of sustainability science and engineering. This new field integrates industrial, social, and environmental processes in a global context. The skills required for this higher level discipline represent a metadisciplinary endeavor, combining information and insights across multiple disciplines and perspectives with the common goal of achieving a desired balance among economic, environmental, and societal objectives. Skills and capabilities that are required to support the new metadiscipline are summarized. Examples of integrative projects are discussed in the areas of sustainability metrics and integration of industrial, societal, and environmental impacts. It is clear that a focus on green engineering that employs pollution prevention and industrial ecology alone are not sufficient to achieve sustainability, because even systems with efficient material and energy use can overwhelm the carrying capacity of a region or lead to other socially unacceptable outcomes. To meet the educational and human resource needs required for this new discipline, the technological and environmental awareness of society must be elevated and a sufficient and diverse pool of human talent must be attracted to this discipline.     

Canavalia brasiliensis seeds. Protein quality and nutritional implications of dietary lectin

This study reports on the performance of rats fed with diets based on Canavalia brasiliensis seed proteins. The raw seeds are not a good regime, causing the animals to lose weight, exhibiting low net protein utilization (NPU) values, high nitrogen excretion and macroscopic alterations of key internal organs. Heat treatment, but not dialysis of the seed meal, had a beneficial effect on the nutritional parameters. Feeding rats with a diet containing pure lectin showed a lower digestibility and NPU, a much higher dry matter and nitrogen excretion, impaired growth rate and small-intestine enlargement in comparison with rats pair-fed on egg-white protein. In addition, lectin was detected fully active against rabbit erythrocytes in the faeces of rats fed lectin-containing diets. It was suggested that the seed lectin acts as an antinutritive dietary component.     

海上风电并网的经济调控——将欧洲经验应用于中国(下)

[目的] 文章为两篇论文中的第二部分,着眼于将欧洲国家的经济调控管理经验应用于中国电力系统当前面临的紧迫挑战之一——海上风电的有效并网。 [方法] 文章通过分析比较调控机制,总结出海上风电监管机制的五个要素：监管实体、有效非绑定程度、补贴管理方法、并网价格制定方法以及责任主体。结合中国国家发改委2015年颁布的电改“9号文”分析了中国并网调控机制及相关机制的变化,这些变化包括为中国并网企业引入单独的经济调控机制,可形象称之为“管住中间、放开两头”。 [结果] 为了确保实现调控目标,如：配置效率、成本效率以及服务质量(包括陆上风电和海上风电的及时连接和输送等),新的监管方法仍需改进。两篇论文中的第一部分基于对三个欧洲案例的研究结果表明：TSO模型、发电机模型和第三方模型,都可以应用于中国。但是考虑到欧洲和中国的差异,建议中国采用和其首要目标最匹配的调控模式。 [结论] 如果中国的首要目标是改善发电和并网的协调发展,激励输电投资,则TSO模式是最好的选择。需要注意的是,采用具有法律约束力的并网计划、并网公司对于未能及时并网确立明晰的责任以及减少弃风弃光的发生,通过独立的监管机构来实施这一模式至关重要。     

Reconstruction of pristine morphology,flow, nutrient conditions and submerged vegetation of lowland river spree (Germany) from palaeomeanders

The European Water Framework Directive requires the definition of reference conditions for each type of surface waters as a base to establish a classification system in which deviations from this high quality status must be determined. In order to reconstruct pristine conditions in the lower river Spree we investigated palaeomeanders using palaeohydrological and palaeolimnological methods. The settlement history of this region suggests low anthropogenic impact for all periods before ～700 cal AD. Three palaeomeanders representing the conditions of the late Sub‐boreal/early Sub‐atlantic were investigated. River width and depth at bankfull stage were reconstructed using cross‐sections of the meanders. Based on these data and experiments on the recent river, a parametric model was developed to calculate the bankfull palaeodischarge. Reconstructions show narrower and shallower channels for the undisturbed lower Spree (～20 m mean width and 0.8 m mean depth at bankfull stage) as compared to recent conditions (35 m and 1.6 m, respectively). Flow velocities and discharge at bankfull stage have been smaller in reconstructed sub‐fossil channels (0.5 m s^?1 and 8 m³ s^?1 in the pristine lower Spree as compared to 0.9 m s^?1 and 52 m³ s^?1 in the recent lower Spree) and flow variability was higher. The increase in bankfull discharge was mainly attributed to deforestation and drainage of the catchment as well as channelization, bank protection and river regulation measures. The organic silt at the base of the sediment cores contained well‐preserved fossil diatom assemblages. Diatom‐inferred total phosphorus (DI‐TP) concentrations of 59–73 µg L^?1 (median 62 µg L^?1) indicate eutrophic to hypertrophic conditions and suggest naturally slightly lower nutrient levels than today. These past nutrient conditions, morphology and large numbers of macrofossil remains indicate optimum growth conditions for submerged macrophytes growth. The combination of palaeohydrological and palaeolimnological parameters proved to be a useful approach for the determination of pristine conditions in a lowland river. Copyright © 2008 John Wiley & Sons, Ltd.     

Comparison of Long-Term Observed Sediment Trap Efficiency with Empirical Equations for Coralville Reservoir, Iowa

Trapping efficiency (TE) is defined as the percent of particles that are retained within an impoundment. TE can vary from ? 0% indicating no sediment is retained or is lost, to 100% where all the sediment is retained. In this paper a high quality, long-term data set (32?years) was used to demonstrate that annual sediment trap efficiencies for a run of the river impoundment are variable. For water years 1973–2005, annual trap efficiencies for Coralville Reservoir ranged from 5.6 to 95.8%, with a mean of 74.7% and a median of 79.9%. Overall trap efficiency for the entire period was determined to be 80.3% and a detention time of 12.4?days. A comparison of the observed long-term TE was done against different empirical TE equations that are commonly used (Brown, Brune, Churchill, Dendy, Heinemann, & USDA/Summit Co., Water District). The Churchill equation provided the best fit of the empirical trap efficiency equations (TEC = 79.1%); all other empirical TE relationships underestimated the observed trap efficiency with errors ranging from 13.7 to 33.1%. Bathymetric data show that since 1958 the reservoir has lost 11% of its flood storage capacity, and over 62% of its normal pool capacity. For the time studied (1973–2005) the loss of storage is estimated to correspond to 16.9×109?kg of sediment deposited in the reservoir, resulting in an annual sedimentation rate of 5.3×108?kg?year?1.