Water circulation in karst systems: comparing physicochemical and environmental isotopic data interpretation     

Joseph Asante  Sam Dotson  Evan Hart  David K. Kreamer 《Environmental Earth Sciences》2018,77(11):421

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Distribution and ecological risks of polycyclic aromatic hydrocarbons (PAHs) in sediments of different tropical water ecosystems in Niger Delta,Nigeria     

Edu Inam  Inemesid Etuk  Nnanake-Abasi Offiong  Kyoung-Woong Kim  Seo-Young Kang  Joseph Essien 《Environmental Earth Sciences》2018,77(5):216

Sediments are considered as suitable matrices to study the contamination levels of aquatic environment since they represent a sink for multiple contaminant sources. In this study, the influence of sediment characteristics on the distribution of polycyclic aromatic hydrocarbons (PAHs) and its potential risk in euryhaline, freshwater and humic aquatic bodies of Douglas/Stubbs creek, Ikpa River and Eniong River, respectively, were investigated. The level of PAHs in sediment was quantified using GC–MS, while sediment properties including total organic carbon (TOC) content and grain size were determined by the wet oxidation and hydrometer methods, respectively. The results revealed that the total levels of PAHs in sediment varied significantly between the euryhaline, freshwater and humic freshwater ecosystems. In Ikpa River freshwater ecosystem, a total PAHs load of 1055.2 ng/g was recorded with the suites concentration ranging from 13.0 ng/g (for acenaphthylene) to 161 ng/g (for pyrene). The humic ecosystem of Eniong River had a total PAH load of 11.06 ng/g, while the suites level recorded ranged from 0.04 ng/g for acenaphthene to 2.65 ng/g for chrysene. The total level of PAHs detected in the euryhaline Douglas/Stubbs creek was 14.47 ng/g, and suite concentrations varied between 4.27 ng/g for naphthalene and 5.13 ng/g for acenaphthylene. This shows variation in quantity and quality of PAH contaminants with the nature of ecosystems. It implies complex and diverse contamination sources as well as different capabilities to recover from PAH contamination. Correlation analysis has shown that sediment particle and TOC content influenced PAHs burden in bottom sediments, but the effects varied with the molecular weight of PAHs and the nature of the ecosystems. The TOC was the most significant determinant of PAHs load and distribution in sediment of the freshwater Ikpa River and euryhaline Douglas/Stubbs but had little or no influence in the humic sediment of Eniong River, while the influence of particle size was generally indefinite but slightly associated with PAHs accumulation in the euryhaline sediment. Generally, the total PAH levels (11.0–1055.2 ng/g) recorded were low and below the allowable limit for aquatic sediments. The ecological risk assessment revealed that these levels were lower than the effects range low and effects range medium values. This indicates no acute adverse biological effect although the accumulation of PAHs in freshwater ecosystem of Ikpa River may pose ecological risks as most of the carcinogenic PAH suites had relatively high pollution indices compared to other ecosystem types studied.  相似文献   

Hydrogeochemistry and water quality assessment of shallow aquifers in the western flanks of Southern Western Ghats,SW India     

Hema Chandrasekharan Nair  Damodaran Padmalal  Ammini Joseph  Vinod Padmakumari Gopinthan 《Arabian Journal of Geosciences》2018,11(4):73

The present study deals with the hydrogeochemistry and water quality of shallow aquifers in two important river basins—the Ithikkara and Kallada river basins—draining the south western flanks of Western Ghats in Kerala, South West India. Well water samples were collected from 20 dug wells with a depth range of 1 m below ground level (mbgl) to 18.2 mbgl during pre-monsoon, monsoon, and post-monsoon seasons of the year 2011–2012. These samples were analyzed for various physico-chemical parameters following standard methods and were evaluated for their interrelations and drinking water suitability. The pH of the water samples shows wide variation from highly acidic to highly alkaline water. About 80% of pre-monsoon samples recorded Fe²⁺ concentration above the permissible limit of drinking water standard. Water Quality Index (WQI) shows that majority of the well water samples fall in the category of excellent–good for drinking purpose. The results of the irrigation suitability assessment using the procedures like Percent Sodium, Sodium Absorption Ratio, Residual Sodium Carbonate, Kelly Index, Permeability Index, and Magnesium Hazard reveal that the well waters of the study area are fit for irrigation purpose. Na⁺/Cl^? ratio reflects the release of sodium to water due to silicate weathering. The samples have a Ca²⁺/Mg²⁺ ratio equal or greater than 2 indicating the effect of silicate minerals in contributing Ca²⁺ and Mg²⁺ ions to the well water. The saturation indices reveal that groundwater is supersaturated with SiO₂. Among the causative factors that determine the hydrochemical quality of well water samples, silicate weathering plays a pivotal role with significant input of ions from anthropogenic sources.  相似文献   

The potential to reduce greenhouse gas emissions in the UK through healthy and realistic dietary change     

Rosemary Green  James Milner  Alan D. Dangour  Andy Haines  Zaid Chalabi  Anil Markandya  Joseph Spadaro  Paul Wilkinson 《Climatic change》2015,129(1-2):253-265

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NIST RM 8301 Boron Isotopes in Marine Carbonate (Simulated Coral and Foraminifera Solutions): Inter‐laboratory δ11B and Trace Element Ratio Value Assignment     

Joseph A. Stewart  Steven J. Christopher  John R. Kucklick  Louise Bordier  Thomas B. Chalk  Arnaud Dapoigny  Eric Douville  Gavin L. Foster  William R. Gray  Rosanna Greenop  Marcus Gutjahr  Freya Hemsing  Michael J. Henehan  Philip Holdship  Yu‐Te Hsieh  Ana Kolevica  Yen‐Po Lin  Elaine M. Mawbey  James W. B. Rae  Laura F. Robinson  Rachael Shuttleworth  Chen‐Feng You  Shuang Zhang  Russell D. Day 《Geostandards and Geoanalytical Research》2021,45(1):77-96

The boron isotopic ratio of ¹¹B/¹⁰B (δ¹¹B_SRM951) and trace element composition of marine carbonates are key proxies for understanding carbon cycling (pH) and palaeoceanographic change. However, method validation and comparability of results between laboratories requires carbonate reference materials. Here, we report results of an inter‐laboratory comparison study to both assign δ¹¹B_SRM951 and trace element compositions to new synthetic marine carbonate reference materials (RMs), NIST RM 8301 (Coral) and NIST RM 8301 (Foram) and to assess the variance of data among laboratories. Non‐certified reference values and expanded 95% uncertainties for δ¹¹B_SRM951 in NIST RM 8301 (Coral) (+24.17‰ ± 0.18‰) and NIST RM 8301 (Foram) (+14.51‰ ± 0.17‰) solutions were assigned by consensus approach using inter‐laboratory data. Differences reported among laboratories were considerably smaller than some previous inter‐laboratory comparisons, yet discrepancies could still lead to large differences in calculated seawater pH. Similarly, variability in reported trace element information among laboratories (e.g., Mg/Ca ± 5% RSD) was often greater than within a single laboratory (e.g., Mg/Ca < 2%). Such differences potentially alter proxy‐reconstructed seawater temperature by more than 2 °C. These now well‐characterised solutions are useful reference materials to help the palaeoceanographic community build a comprehensive view of past ocean changes.  相似文献   

Synoptic conditions and potential causes of the extreme heavy rainfall event of January 2009 over Mindanao Island,Philippines     

Olaguera  Lyndon Mark Payanay  Caballar  Michelle Español  De Mata  Joseph Cabacungan  Dagami  Loida Ann Torres  Matsumoto  Jun  Kubota  Hisayuki 《Natural Hazards》2021,109(3):2601-2620

Natural Hazards - This study investigates the synoptic conditions that led to the heavy rainfall/flood (HRF) event in Mindanao Island, Philippines (122??127°E;...  相似文献   

Managed out of existence: over-regulation of Indigenous subsistence fishing of the Yukon River     

Victoria Walsey  Joseph Brewer 《GeoJournal》2018,83(5):1169-1180

Humans are adversely affected by the loss of vital fishery resources, specifically Indigenous peoples and the traditional knowledge systems that are foundationally tied to their culture. Discounting the ability and knowledge of Indigenous peoples stems from concepts rooted in “Tragedy of the Commons” in which a shared resource, in this case fisheries, if left unchecked will be destroyed by the mismanagement of users. The Alaskan fisheries policy regime is recognized as one of the best managed and influential fisheries in the world, but the state is predominantly driven by a conservation approach that discounts other knowledge systems. Alaskan Native fishers, for example the Gwich’in, who maintain a sustainable 30,000 year (conservatively) relationship with their environment, possess culturally specific Traditional Ecological Knowledge (TEK) that is a result of the mechanisms or physical act of fishing, thus giving meaning to the term we will use in this paper, Indigenous Fishers’ Knowledge (IFK). Alaskan Natives along the Yukon River derive specific knowledge about their environment and King Salmon through the act of fishing. TEK is not static nor is IFK as it is transmitted to younger generations through the practice of fishing. TEK and IFK play a large role in the transmission and acquisition of knowledge, they both connect knowledge to culture and play a role in creating culture and traditions, they are in fact very intricate systems. Indigenous fishers seek inclusion and involvement that does not separate them from their knowledge but recognizes and implements their practices/control on a local level.  相似文献   

On the track of the elusive Sudbury impact: geochemical evidence for a chondrite or comet bolide          下载免费PDF全文

Joseph A. Petrus  Doreen E. Ames  Balz S. Kamber 《地学学报》2015,27(1):9-20

Siderophile and lithophile trace element data for 69 samples from the Sudbury impact crater fill (Onaping Formation) and quartz diorite offset dikes help constrain the sources of the established moderately elevated platinum group element signature associated with the impact structure. The siderophile element distribution of the crater fill requires contributions from bulk continental crust, mafic rocks and a chondritic component. A mantle component is absent, but the involvement of mid to lower crust is implied. After considering post‐impact hydrothermal alteration, melt heterogeneity and mafic target admixture, the projectile elemental ratios were determined on a more robust data subset. Chondrite discrimination diagrams of these ratios identify an ordinary or enstatite chondrite as the most probable source of meteoritic material in the Sudbury crater fill. However, the relative and absolute siderophile element distributions within the impact structure as well as bolide size models are congruent with the bolide being a comet that had a chondritic refractory component.  相似文献   

Petrogenetic variability along the North–South Propagating Spreading Center of the North Fiji Basin     

C. Fleutelot  J.-P. Eissen  L. Dosso  T. Juteau  P. Launeau  C. Bollinger  J. Cotten  L. Danyushevsky  L. Savoyant 《Mineralogy and Petrology》2005,83(1-2):55-86

Summary Previous studies on propagating rifts suggested that segmentation of a spreading axis could represent the superficial mark of mantle behavior (Sinton et al., 1983; Nicolas, 1989; Gente et al., 1995). The study of North–South Propagating Spreading Center (NS-PSC) from the North Fiji Basin (NFB) brings new insights to this debate. Basalts from the central part of the propagator have more variable incompatible and isotopic ratios then those from its northern tip. A model of dynamic partial melting of a thermally and slightly geochemically and isotopically heterogeneous mantle is proposed. Beneath the central segment, the partial fusion starts deeper (ca. 30km) and reaches a higher rate (ca. 22%). Further open system differentiation occurs within shallow permanent magma reservoirs along most of the central segment. Below the segment closest to the tip of the propagator the partial fusion starts shallower (ca. 25km) and stays at a lower rate (ca. 16%). The maximum of differentiation occurs close to the propagator, in small, periodically disconnected, magma bodies resulting in the production of ferrobasalts close to the tip. In order to explain these variations, the presence of an asthenospheric diapir focused beneath the central part of the NS-PSC is proposed. The petrogenetic processes of propagating spreading centers of mature oceanic basins or back-arc basins are identical.  相似文献   

    

K. T. Joseph 《GeoJournal》1982,4(1):66-70

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