Oxygen-Containing Compounds Identified in Groundwater from Fuel Release Sites Using GCxGC-TOF-MS     

Kirk T. O'Reilly  Rachel E. Mohler  Dawn A. Zemo  Sungwoo Ahn  Renae I. Magaw  Catalina Espino Devine 《Ground Water Monitoring & Remediation》2019,39(4):32-40

This research continues a 7-year study of oxygen-containing organic compounds present in groundwater at gasoline and diesel fuel release sites that are quantified as diesel-range “total petroleum hydrocarbons” when measured by methods utilizing solvent extraction and gas chromatography. Two-dimensional gas chromatography with time-of-flight mass spectrometry was used to tentatively identify 1162 compounds (TICs) in 113 groundwater samples from 22 sites. Samples were collected from wells either upgradient of the release, within the source zone, or downgradient of the source but still within the plume of dissolved organics associated with release. The names and formulas of all TICs found in samples from each well type are presented and the results from upgradient and downgradient locations are compared in detail. About 60% of the most frequently detected TICs in downgradient wells were also detected in upgradient wells. A majority of these were saturated straight chain alkyl acids, commonly called fatty acids, or fatty acid esters. Of TICs frequently detected in downgradient wells but not upgradient wells, over half were branched alkyl alcohols. Hierarchical cluster analysis results suggest about 80% of the chemical composition of downgradient samples is more similar to upgradient samples than to source area samples. This similarity is due to the presence of the same types of fatty acids and esters. Principal component analysis indicates a continuum of biodegradation between the source area and downgradient samples with the latter becoming more consistent with upgradient samples. Results suggest some TICs may not be petroleum degradation intermediates but compounds synthesized by microorganisms through secondary production and carbon cycling.  相似文献   

Rock slope failure in a recently deglaciated permafrost rock wall at Piz Kesch (Eastern Swiss Alps), February 2014          下载免费PDF全文

Marcia Phillips  Andrea Wolter  Rachel Lüthi  Florian Amann  Robert Kenner  Yves Bühler 《地球表面变化过程与地形》2017,42(3):426-438

In February 2014, a rock pillar with a volume of around 150 000  m³ collapsed at Piz Kesch in the Eastern Swiss Alps. A reconstruction of the conditions prior to the event and of the event itself is presented on the basis of different sources of data. The methods applied include photogrammetry, terrestrial laser scanning, structural geological analysis, examination of meteorological data, carbon‐14 (¹⁴C) dating of organic material in permafrost ice from a tension crack and numerical modelling of likely modes of failure. Despite a complete lack of in situ measurements in the rock wall prior to the event and of direct observations during the event, the available data allow the determination of the approximate timing of the event as well as the structural predisposition, the probable mode of failure and the timescale of several millennia involved in the triggering of the failure of the rock pillar. The interdisciplinary analysis of this event contributes towards understanding the complex interaction of processes involved in large rock slope failures currently occurring in warming mountain permafrost regions. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Effects of Planting Field on Groundwater and Surface Water Pollution in China     

Yaa Opoku‐Kwanowaa  Rachel Kasoro Furaha  Li Yan  Daming Wei 《洁净——土壤、空气、水》2020,48(5-6)

Water forms an essential resource for life on earth because all living things on earth depend on water for life activities. However, with the increase in the human population, which is coupled with intense urbanization and agricultural activities, global water pollution has increased over the past decades. In China, agricultural activities that occure mainly in the planting fields have been listed as the main source of surface water and groundwater pollution. This review focuses on the major factors that influence pollution from planting fields in China mainly as a result of farming activities such as flood irrigation, excessive application of fertilizers and pesticides, and poor management practices. At present, good results are achieved by adopting soil fertilization test formula, biodegradable pesticides, proper irrigation, and agroforestry interventions. In the future, pollution from planting fields as a non‐point source of water pollution can be improved and resolved by perfect nutrient management, best management practices, organic amendments, restoring water environment, and intelligent assessment management.  相似文献   

Microplastic Contamination in Karst Groundwater Systems     

Samuel V. Panno  Walton R. Kelly  John Scott  Wei Zheng  Rachel E. McNeish  Nancy Holm  Timothy J. Hoellein  Elizabeth L. Baranski 《Ground water》2019,57(2):189-196

Groundwater in karst aquifers constitutes about 25% of drinking water sources globally. Karst aquifers are open systems, susceptible to contamination by surface-borne pollutants. In this study, springs and wells from two karst aquifers in Illinois, USA, were found to contain microplastics and other anthropogenic contaminants. All microplastics were fibers, with a maximum concentration of 15.2 particles/L. The presence of microplastic was consistent with other parameters, including phosphate, chloride and triclosan, suggesting septic effluent as a source. More studies are needed on microplastic sources, abundance, and impacts on karst ecosystems.  相似文献   

Local government perspectives on rural retirement migration and social sustainability     

Rachel Winterton  Andrew Butt  Bradley Jorgensen  John Martin 《The Australian geographer》2019,50(1):111-128

Within the policy and academic literature, the impact of rural retirement migration (RRM) on community sustainability has been questioned. This qualitative study investigated the perceived impact of retirement migration on rural social sustainability from a local government perspective. Focus groups were conducted with local government senior managers and community services staff (n = 39) across six rural local government areas in one Australian state. Data were analysed against the three components of rural social sustainability (equity, community and rurality) proposed by Jones and Tonts [1995. “Rural Restructuring and Social Sustainability: Some Reflections on the Western Australian Wheatbelt.” Australian Geographer 26: 133–140]. While RRM is perceived to benefit rural community capacity to facilitate or maintain equity, community and rurality, it also presents challenges for local government. Participants suggested that capacity to facilitate equity, community and rurality in contexts of RRM was impacted by uncertainty around future impacts of RRM on population ageing, increasing advocacy and expectations of older in-migrants, and the impact of RRM on rural heterogeneity. These issues required local governments to think critically about how to accommodate and manage the needs and expectations of older in-migrants, while mediating potential impacts associated with RRM.  相似文献   

Perceived attributes of hurricane-related retrofits and their effect on household adoption     

Zou  Yilin  Stock  Alexia  Davidson  Rachel  Nozick  Linda  Trainor  Joseph  Kruse  Jamie 《Natural Hazards》2020,104(1):201-224

Natural Hazards - Understanding how homeowners make protective action decisions is important for designing policies and programs to encourage those actions and community resilience as a whole. This...  相似文献   

Macrofaunal density, biomass and composition of estuarine sediments and their relationship to the river plume of the Rhone River (NW Mediterranean)     

Rachel Hermand  Chantal Salen-Picard  Elisabeth Alliot  Claude Degiovanni 《Estuarine, Coastal and Shelf Science》2008,79(3):367-376

This study investigates species community patterns and sediment relationships of benthic macrofauna off the Rhone river delta. Along a WE transect, changes in diversity, density, biomass and trophic structure were coupled with the mean extension of the river dilution plume. Species number and diversity were at a minimum off the river mouth, below the area of the minimum surface salinity. Density decreased by a factor 2 and biomass by a factor 5 from the fluvial to the marine system. These features are due to high overload of terrestrial organic matter in the river prodelta as evidenced by the carbon isotopic signature of surface sediment and by pigment content. On the basis of a non-metric MDS analysis and of Dufrêne and Legendre method (1997), groups of stations and characteristic species associated were identified. These species, mainly small capitellids, spionids, lumbrinerids and sternaspids, correspond to a successional dynamic in response to changes in sedimentation conditions, mainly in organic matter quality of the surface sediment. The succession observed in space was similar to described in macrotidal estuaries and off other deltaic systems all over the world and to that observed in time following the Rhone river severe flood events. Results suggest that organic matter quality is an important factor with regard to benthic macrofauna successions and recovery mechanisms following disturbances. The differences observed between the Rhone deltaic system and the general model of relations between shelf processes and discharge of large rivers are attributed to a more regular supply of organic material from terrestrial origin on the Rhone continental shelf.  相似文献   

Cataclysmic variables based on the stellar spectral survey LAMOST DR3     

Xianming L.Han  Li-Yun Zhang  Jian-Rong Shi  Qing-Feng Pi  Hong-Peng Lu  Li-Bo Zhao  Rachel K.Terheide  Lin-Yang Jiang 《天文和天体物理学研究(英文版)》2018,(6)

Big data in the form of stellar spectra from the spectroscopic survey associated with the Large Sky Area Multi-object Fiber Spectroscopic Telescope(LAMOST) are important for studying properties of cataclysmic variables(CVs). By cross matching the catalogs of CVs compiled with LAMOST DR3,acquired from October 2011 to July 2015, we obtained the first spectroscopic catalog for CVs observed by LAMOST with high signal to noise ratio, above 8. By integrating line profiles, their equivalent widths(EWs) of the Hα, Hβ, Hγ and Hδ, as well as He I 5876 and 6678 A? lines, were calculated. There were74 stellar spectra from 48 known CVs and three spectra from three new CV candidates. At the same time, we also collected their previously published EWs. Thirty-three objects had repeated spectra and30 stars showed spectral variability in the Hα line. Moreover, we carried out photometric follow-up studies for five CVs(UU Aqr, TT Tri, PX And, BP Lyn and RW Tri). We obtained nine new light curves and revised their linear ephemerides. For RW Tri, there is a possible oscillation with an amplitude of0.0031(2) days and a period of 47.6±0.4 years, which might be caused by a third body(brown dwarf)or magnetic activity cycle.  相似文献