Challenges in the use of gross alpha and beta screening in nuclear waste characterisation and land remediation.

Gross alpha & beta measurement is a widely used technique for rapid screening of radionuclide content. The study evaluated the influence of geometry, alpha & beta energy and presence of natural decay chain nuclides on the observed gross alpha & beta response. Measured calibration data were validated using Monte Carlo-based modelling.

The distribution and enrichment of trace elements in surface and core sediments from the Changjiang River Estuary, China: Evidence for anthropogenic inputs and enhanced availability of rare earth elements (REE).

Huge amount of trace metals emitted through manmade activities are carried by the Changjiang River into the East China Sea. Most of them deposit in the Changjiang River Estuary and threaten the regional aquatic environment. In this study, major and trace elements of 34 archive surface sediments and two cores are examined.

Environmental risk of trace metals and metalloids in estuarine sediments: An example from Southampton Water, U.K.

Industrial and commercial port activities are widely recognized worldwide as an important source of pollution to proximal estuaries. In this study, we analysed geochemical and sedimentological parameters including major and trace elements, organic matter and sediment texture in surface sediments from the estuarine environment of Southampton Water, U.K.

A compact, dual-zone vertical tube furnace for the determination of tritium and carbon-14 in decommissioning wastes.

A compact dual zone, two work-tube, vertical tube furnace system (Raddec Pyrolyser-Mini) has been designed for the determination of H-3 and C-14 in decommissioning wastes. An optimised methodology was developed following improvements to sample holder and bubbler trap design, sample loading and loading temperature, as well as length and style of heating programmes. A significant efficiency enhancement was obtained through 'hot-loading' of the sample into the furnace at 600 °C before finally ramping to 900 °C.

Development of a numerical simulation method for modelling column breakthrough from extraction chromatography resins.

A numerical simulation method has been developed to describe the transfer of analytes between solid and aqueous phases and assessed for a commercially available extraction chromatography resin (UTEVA resin). The method employs an ordinary differential equation solver within the LabVIEW visual programming language. The method was initially developed to describe a closed batch system.

Assessing the role of the "estuarine filter" for emerging contaminants: pharmaceuticals, perfluoroalkyl compounds and plasticisers in sediment cores from two contrasting systems in the southern U.K.

The environmental occurrence, fate and ecotoxicity of emerging contaminants (ECs) has been the subject of increasing research, policy and public concern over the past two decades. While a wide range of publications have examined the environmental persistence and sediment/soil interactions of ECs following their discharge into aquatic environments, the extent to which ECs are sequestered in estuarine sediments, and the impact of this on their environmental persistence and supply to the ocean, in comparison remains unclear. This Article examines the environmental concentrations of seven, relatively water-soluble and environmentally mobile, ECs (including pharmaceuticals, perfluoroalkyl compounds, and plasticisers) in dated intertidal saltmarsh cores from two contrasting estuarine sites in the southern U.

Measuring anthropogenic impacts on an industrialised coastal marine area using chemical and textural signatures in sediments: A case study of Augusta Harbour (Sicily, Italy).

From the early 1950s until the late 1970s, Augusta Bay (Sicily, Italy) served as a major European (petro) chemical hub. It thereafter began a progressive decline as several crude oil refining and industrial plants closed due to the transfer of production cycles to other sites around the globe. As a result of the rapid and relatively uncontrolled post-WWII development of the site, several environmental studies identified significant contamination in sediments around the southernmost sector of the bay.

Human settlement of East Polynesia earlier, incremental, and coincident with prolonged South Pacific drought.

The timing of human colonization of East Polynesia, a vast area lying between Hawai'i, Rapa Nui, and New Zealand, is much debated and the underlying causes of this great migration have been enigmatic. Our study generates evidence for human dispersal into eastern Polynesia from islands to the west from around AD 900 and contemporaneous paleoclimate data from the likely source region. Lake cores from Atiu, Southern Cook Islands (SCIs) register evidence of pig and/or human occupation on a virgin landscape at this time, followed by changes in lake carbon around AD 1000 and significant anthropogenic disturbance from c.

Tracing lake pollution, eutrophication and partial recovery from the sediments of Windermere, UK, using geochemistry and sediment microfabrics.

Many lakes undergo anthropogenically driven eutrophication and pollution leading to decreased water and sediment quality. These effects can enhance seasonally changing lake redox conditions that may concentrate potentially toxic elements. Here we report the results of a multi-method geochemical and sediment microfabric analysis applied to reconstruct the history of cultural eutrophication and pollution of the North and South Basins of Windermere, UK.

Rapid assessment of heavy metal pollution using ion-exchange resin sachets and micro-XRF core-scanning.

Conventional pollution monitoring strategies for heavy metals are often costly and unpractical. Innovative sampling and analytical approaches are therefore needed to efficiently monitor large areas. This study presents a novel, simple, fast, and inexpensive method to monitor heavy metal pollution that uses cation-exchange resin sachets and the micro-XRF core-scanning technique (XRF-CS).

Sediment structure and physicochemical changes following tidal inundation at a large open coast managed realignment site.

Managed realignment (MR) schemes are being implemented to compensate for the loss of intertidal saltmarsh habitats by breaching flood defences and inundating the formerly defended coastal hinterland. However, studies have shown that MR sites have lower biodiversity than anticipated, which has been linked with anoxia and poor drainage resulting from compaction and the collapse of sediment pore space caused by the site's former terrestrial land use. Despite this proposed link between biodiversity and soil structure, the evolution of the sediment sub-surface following site inundation has rarely been examined, particularly over the early stages of the terrestrial to marine or estuarine transition.

A rapid method for assessing the accumulation of microplastics in the sea surface microlayer (SML) of estuarine systems.

Microplastics are an increasingly important contaminant in the marine environment. Depending on their composition and degree of biofouling, many common microplastics are less dense than seawater and so tend to float at or near the ocean surface. As such, they may exhibit high concentrations in the sea surface microlayer (SML - the upper 1-1000 μm of the ocean) relative to deeper water.

Historical trace element accumulation in marine sediments from the Tamaulipas shelf, Gulf of Mexico: An assessment of natural vs anthropogenic inputs.

Unlabelled: The Gulf of Mexico is considered one of the world's major marine ecosystems, supporting important fisheries and habitats such as barrier islands, mangrove forests, seagrass beds, coral reefs etc. It also hosts a range of complex offshore petroleum exploration, extraction, and refining industries, which may have chronic or acute impacts on ecosystem functioning. Previous work on the marine effects of this activity is geographically incomplete, and has tended to focus on direct hydrocarbon impacts, while impacts from other related contaminants (e.

Rapid on-site radionuclide screening of aqueous waste streams using dip-stick technologies and liquid scintillation counting.

This paper describes an early-stage evaluation of a purpose-designed extraction/detection system that can be deployed by non-specialists either on-site or as part of a mobile laboratory. The system comprises three main components; (1) an optimised compact extraction system for recovery of radionuclides from the waste form; (2) an extraction test strip designed to recover the radionuclides from the waste digest; (3) a scintillation-based detection system capable of quantification of alpha, low energy beta and high energy beta emitting radionuclides. Data are presented on the preliminary assessment of the extraction/detection system for the measurement of Sr and Tc in aqueous wastes.

Liquid scintillation counters calibration stability over long timescales.

Liquid scintillation spectrometry is widely used for the analysis of alpha and beta emitting radionuclides. Robust calibration of liquid scintillation (LS) spectrometers is fundamental to accurate LS measurement but at the same time is time consuming and costly, particularly if a wide range of radionuclides are analysed by the laboratory. The frequency of the calibration varies in different laboratories and is based on many practical and operational factors.

A new bomb-combustion system for tritium extraction.

Quantitative extraction of tritium from a sample matrix is critical to efficient measurement of the low-energy pure beta emitter. Oxidative pyrolysis using a tube furnace (Pyrolyser) has been adopted as an industry standard approach for the liberation of tritium (Warwick et al. in Anal Chim Acta 676:93-102, 2010) however pyrolysis of organic-rich materials can be problematic.

Feedback of the third interlaboratory exercise organised on wheat in the framework of the OBT working group.

Organically bound tritium (OBT) has become of increasing interest within the last decade, with a focus on its behaviour and also its analysis, which are both important to assess tritium distribution in the environment and dose consequences. After the first OBT International Workshop which was held in France in May 2012, an international working group was created. The expected benefits are the following: remove or reduce uncertainty in OBT analysis results, provide better OBT model validation data and better public dose results, increase the number of potential measuring OBT laboratories, validate all of the stages of the procedures based on a larger population and more statistically significant results, and investigate the feasibility of CRM's and RM's production.

The Fate of Contaminants and Stable Pb Isotopes in a Changing Estuarine Environment: 20 Years On.

Estuarine sediments provide an important sink for contaminants discharged into fluvial, estuarine, and nearshore settings, and numerous authors have utilized this trapping function to assess historical contaminant loadings and contaminant breakdown/transformation processes. This Article examines the retention of elemental and isotopic sedimentary signatures in an industrialized estuarine system subject to a strongly upward sea-level trend, over a 20 year period. Two contrasting saltmarsh sites (at Hythe and Hamble, part of the wider Southampton Water estuarine system, UK) were examined, which had been previously cored and analyzed in the early 1990s.

Fusion Bead Procedure for Nuclear Forensics Employing Synthetic Enstatite to Dissolve Uraniferous and Other Challenging Materials Prior to Laser Ablation Inductively Coupled Plasma Mass Spectrometry.

There is an increasing demand for rapid and effective analytical tools to support nuclear forensic investigations of seized or suspect materials. Some methods are simply adapted from other scientific disciplines and can effectively be used to rapidly prepare complex materials for subsequent analysis. A novel sample fusion method is developed, tested, and validated to produce homogeneous, flux-free glass beads of geochemical reference materials (GRMs), uranium ores, and uranium ore concentrates (UOC) prior to the analysis of 14 rare earth elements (REE) via laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS).

Lake sedimentary DNA accurately records 20 Century introductions of exotic conifers in Scotland.

Sedimentary DNA (sedDNA) has recently emerged as a new proxy for reconstructing past vegetation, but its taphonomy, source area and representation biases need better assessment. We investigated how sedDNA in recent sediments of two small Scottish lakes reflects a major vegetation change, using well-documented 20 Century plantations of exotic conifers as an experimental system. We used next-generation sequencing to barcode sedDNA retrieved from subrecent lake sediments.

Applying multivariate statistics to discriminate uranium ore concentrate geolocations using (radio)chemical data in support of nuclear forensic investigations.

The application of Principal Components Analysis (PCA) to U and Th series gamma spectrometry data provides a discriminatory tool to help determine the provenance of illicitly recovered uranium ore concentrates (UOCs). The PCA is applied to a database of radiometric signatures from 19 historic UOCs from Australia, Canada, and the USA representing many uranium geological deposits. In this study a key process to obtain accurate radiometric data (gamma and alpha) is to digest the U-ores and UOCs using a lithium tetraborate fusion.

A rapid dissolution procedure to aid initial nuclear forensics investigations of chemically refractory compounds and particles prior to gamma spectrometry.

A rapid and effective preparative procedure has been evaluated for the accurate determination of low-energy (40-200 keV) gamma-emitting radionuclides ((210)Pb, (234)Th, (226)Ra, (235)U) in uranium ores and uranium ore concentrates (UOCs) using high-resolution gamma ray spectrometry. The measurement of low-energy gamma photons is complicated in heterogeneous samples containing high-density mineral phases and in such situations activity concentrations will be underestimated. This is because attenuation corrections, calculated based on sample mean density, do not properly correct where dense grains are dispersed within a less dense matrix (analogous to a nugget effect).

Determination of ¹³⁵Cs and ¹³⁷Cs in environmental samples: A review.

Radionuclides of caesium are environmentally important since they are formed as significant high yield fission products ((135)Cs and (137)Cs) and activation products ((134)Cs and (136)Cs) during nuclear fission. They originate from a range of nuclear activities such as weapons testing, nuclear reprocessing and nuclear fuel cycle discharges and nuclear accidents. Whilst (137)Cs, (134)Cs and (136)Cs are routinely measurable at high sensitivity by gamma spectrometry, routine detection of long-lived (135)Cs by radiometric methods is challenging.

Establishing geochemical background levels of selected trace elements in areas having geochemical anomalies: The case study of the Orbetello lagoon (Tuscany, Italy).

The determination of background concentration values (BGVs) in areas, characterised by the presence of natural geochemical anomalies and anthropogenic impact, appears essential for a correct pollution assessment. For this purpose, it is necessary to establish a reliable method for determination of local BGVs. The case of the Orbetello lagoon, a geologically complex area characterized by Tertiary volcanism, is illustrated.

Calixarene-based extraction chromatographic separation of ¹³⁵Cs and ¹³⁷Cs in environmental and waste samples prior to sector field ICP-MS analysis.

Advances in the sensitivities achievable by sector field inductively coupled plasma mass spectrometry (ICP-SFMS) offer the prospect of low-level measurement of shorter and longer lived radionuclides, thus expanding options for environmental and radioactively contaminated land assessment. In ICP-SFMS, the critical requirement for accurate detection is the effective chemical separation of isobaric and polyatomic interferences prior to sample introduction. As instrumental detection limit capability improves, accurate radionuclide determination requires highly effective separation materials that combine high analyte selectivity with subsequent quantitative analyte recovery compatible with ICP-SFMS detection.