Effects of single and combined exposures to benzo(a)pyrene and 3,3'4,4'5-pentachlorobiphenyl on EROD activity and development in Fundulus heteroclitus

The goal of this study was to assess the interactive effects of a polynuclear aromatic hydrocarbon (PAH), benzo(a)pyrene (BaP), and a co-planar halogenated aromatic hydrocarbon (HAH), 3,3'4,4'5-pentachlorobiphenyl (PCB 126) on ethoxyresorufin-O-deethylase (EROD) activity and occurrence of deformities in Fundulus heteroclitus. While each compound administered alone elicited dose-dependent increases in EROD activity, the combined treatment of these two compounds generally did not elicit an additive EROD response. There was a significant correlation between deformity occurrence and EROD induction in embryos dosed with PCB alone but not for embryos dosed with BaP alone, or a combination of BaP and PCB 126.     

黔西南卡林型金矿床与区域古油藏的关系:来自流体包裹体气相组成和沥青拉曼光谱特征的证据

黔西南地区是世界第二大卡林型金矿床集中区,同时也发育有大量古油藏,二者空间关系密切,但是否具有成因联系目前尚不清楚且存在较大争议。本文报道该区典型金矿床与成矿有关的热液矿物中流体包裹体的气相组成和高品位金矿石中沥青的激光拉曼光谱分析结果,以探讨含有机质流体与金成矿作用之间的关系。研究表明,虽然含砷富金黄铁矿、石英、方解石、萤石和雄黄等热液矿物形成于不同的成矿阶段,但其中流体包裹体的有机气相组分种类、含量及相对比例整体较为一致,表明成矿流体中的有机络离子团在成矿作用过程中没有发生明显的分解或重组,进而说明黔西南卡林型金矿成矿作用过程中有机质并未以有机络离子团的形式对金进行有效搬运或其搬运金的能力非常有限。在N2/Ar-CO2/CH4流体来源判别图解中,各蚀变矿物中的流体包裹体气相组成主要落在循环的大气降水区域,经大气水区域向岩浆流体区域延伸,整体上构成一条非常好的线性分布趋势,暗示成矿流体可能起源于深部岩浆但在演化过程中有大量循环大气水的加入。水银洞金矿床的1件石英样品偏离上述趋势线并向有机流体方向偏移,可能反映了流体迁移过程中有机质的加入。该区金矿床的矿石中均不同程度地发育浸染状沥青,不同矿床中沥青的激光拉曼光谱特征基本一致,说明该区金矿床中的沥青具有相同成因。根据沥青激光拉曼光谱特征地质温度计反演计算的成矿早阶段流体温度为317~336℃,明显高于区域古地温温度(160~250℃)以及区域古油藏的流体包裹体均一温度(73~175℃),说明该区卡林型金矿床的成矿热源与区域古地温无关。对区域地质及近年来地球物理与地球化学最新成果的综合分析表明,该区卡林型金矿床可能是叠加在区域古地温场之上的深部岩浆活动远端低温热液成矿作用的产物,与金矿床空间关系密切的有机质可能为来自先存古油藏并沿控矿构造发生逃逸的油气物质裂解产物,金成矿与区域古油藏之间不存在成因联系。     

Bottom sediments in a polluted marine environment,upper Saronikos Gulf,Greece

The domestic and industrial waste water from most of the greater Athens, Greece area is discharged into shallow water at the upper end of the semi-enclosed Saronikos Gulf. The lack of circulation and excess organic matter has led to the formation of a rapidly expanding sludge field. Black anoxic sediments high in organic carbon now cover almost 9 sq km of sea floor and contain high concentrations of heavy metals. Maximum increases above background values range from 22× for mercury, 1500× for arsenic, 1200× for chromium, to 3000× for zinc. The principal sources of metals are 1) a fertilizer factory, 2) the Athens sewer outfall, and 3) the industries in eastern Elefsis Bay.     

Optimal Technology R&D in the Face of Climate Uncertainty

This paper explores optimal near-term technology R&D in the face of uncertain damages caused by the buildup of greenhouse gases. The paper puts particular emphasis on understanding how optimal near-term R&D expenditures might vary based on the technologies pursued in the R&D program. The exploration is conducted in the context of varying impacts from R&D on the global abatement cost function. The R&D planning problem is considered first within a theoretical framework and is then pursued in a stylized application using the DICE model. The paper provides intuition into the circumstances under which near-term technology R&D might increase or decrease under uncertainty, thereby serving as a hedge against climate uncertainty.     

A northwest North American training set: distribution of freshwater midges in relation to air temperature and lake depth

Freshwater midges, consisting of Chironomidae, Chaoboridae and Ceratopogonidae, were assessed as a biological proxy for palaeoclimate in eastern Beringia. The northwest North American training set consists of midge assemblages and data for 17 environmental variables collected from 145 lakes in Alaska, British Columbia, Yukon, Northwest Territories, and the Canadian Arctic Islands. Canonical correspondence analyses (CCA) revealed that mean July air temperature, lake depth, arctic tundra vegetation, alpine tundra vegetation, pH, dissolved organic carbon, lichen woodland vegetation and surface area contributed significantly to explaining midge distribution. Weighted averaging partial least squares (WA-PLS) was used to develop midge inference models for mean July air temperature (r _boot² = 0.818, RMSEP = 1.46°C), and transformed depth (ln (x+1); r _boot² = 0.38, and RMSEP = 0.58).     

Experimental implementation and verification of multi‐degrees‐of‐freedom effective force testing

This paper presents an experimental implementation and verification of multi‐degrees‐of‐freedom effective force testing (MDOF‐EFT). An experimental setup that consists of a two‐degrees‐of‐freedom structural system and two hydraulic actuators at the Johns Hopkins University was utilized in this study. First, experimental system identification was performed to develop compatible analytical models for the multi‐input and multi‐output systems. Dynamics of the control plant, that is, the valve‐to‐force relations, were modeled with a rational polynomial transfer function matrix and delay components. By using the analytical model, a centralized decoupling loop‐shaping force feedback controller was designed such that the forces are uncoupled and the loop transfer functions have desirable dynamic characteristics in the frequency domain. Then, a series of harmonic force and earthquake simulation tests were performed to assess capabilities and limitations of MDOF‐EFT. Experimental results showed that the dynamic forces in the two actuators were accurately controlled to provide tracking while the system was stable and robust for the entire period of the experiment. Furthermore, earthquake simulation tests with increased levels of the reference forces demonstrated the feasibility of MDOF‐EFT with highly nonlinear test structures. Copyright © 2013 John Wiley & Sons, Ltd.     

Affordable Enteric Virus Detection Techniques Are Needed to Support Changing Paradigms in Water Quality Management

In light of water quality monitoring paradigms shifting to a more holistic approach, it is essential that environmental microbiologists embrace new methodological developments in clinical virology to create rapid, laboratory‐free methods for the identification of wastewater pollution. It is widely accepted that routine monitoring of fecal indicator bacteria (FIB) does not adequately reflect human health risks associated with fecal pollution, especially risks posed by viruses. Enteric viruses are typically more resistant to wastewater treatment and persist longer in the environment than FIB. Furthermore, enteric viruses often have extremely low infectious doses. Currently, the incorporation of sanitary surveys, short‐term monitoring of reference pathogens, exploratory quantitative microbial risk assessments, and predictive ecological models is being championed as the preferred approach to water management. In addition to improved virus concentration methods, simple, point‐of‐use tests for enteric viruses and/or improved viral indicators are needed to complement this emerging paradigm and ensure microbial safety worldwide.

     

Spatial and temporal variation of diverse inter‐tidal algal assemblages in Southwest O‘ahu

Spatial and temporal variation in tropical inter‐tidal communities is poorly known, making predictions about the effects of climate change and other anthropogenic disturbances difficult. Along Southwest O‘ahu, Hawai'i, local residents are concerned about the environmental effects of coastal development and the perceived loss of targeted algal species, which are collected for human consumption. To describe the coastal benthic community and better understand the processes that form and maintain it, the abundance and composition of macroalgae were sampled in the region's inter‐tidal zone from 2006 to 2015. Sixty‐six macroalgal species and two broad algal assemblages were identified that corresponded to substrate topography and sand influence at a similar tidal elevation. Along flat carbonate benches with a sand beach, Phaeophyceae and Rhodophytes occurred in almost equal proportions, while shores with slightly more topographic relief and angular substrate were dominated by Rhodophytes. Foliose or turf algal forms were most common. Surveys captured the local invasion of an alga, Avrainvillea sp. and significant declines in abundant macroalgae in 2015 after a period of unseasonably warm, calm water. Temporal changes in algal assemblages were related to maximum water temperature and wave height but not precipitation. Thus, algal assemblages appear to be structured by local beach morphology as they interact with sand and wave activity and episodically by unusual weather events. However, manipulation and continuous monitoring of the algal assemblages coupled to sensing of the localized environment is necessary to confirm factors related to assembly maintenance and recent species shifts.     

Magnetic susceptibility as a proxy for coal ash pollution within riverbed sediments in a watershed with complex geology (southeastern USA)

A study of near surface sediments from the Dan River (southeastern USA) was conducted to assess the use of magnetic properties as proxies of coal ash after a recent spill. The watershed geology is diverse and potentially contributes magnetic minerals to riverbed sediment from diabase dikes in the Dan River Triassic Basin and from granitic gneiss outside the basin. Coal ash is heterogeneous, including aluminosilicate spheres, amorphous particles and carbonaceous rods and lacy particles. The magnetic fraction of ash from the failed storage pond is up to 17 wt% and is mostly composed of black spheres with maghemite and magnetite. Ash was detected in riverbed sediment from quiet water settings such as inside of meander bends, the confluence of tributary streams and near islands between the spill site and 20 miles downstream in the Schoolfield Reservoir, Danville, VA. The strong magnetic signal is detected above background in riverbed samples and is strongly positively correlated with total ash; elevated low field magnetic susceptibility (χ _LF) is evident in samples with ≥ 12% ash content. Anhysteretic remanent magnetization and hysteresis parameters delineate native sediment, ash-bearing sediment, and diabase dikes. Between 20 and 70 miles downstream of the spill site, ash concentrations were either buried or too low due to dilution with native sediment to be detected with χ _LF in riverbed samples.