1,721,007 research outputs found
University of Southampton co-ordinated response to: The NDA group Draft Strategy 2025 for public consultation
No full textThe University of Southampton's co-ordinated response to The NDA group Draft Strategy 2025 for public consultation
A critical review of sampling, extraction and analysis methods for tyre and road wear particles
No full textTyre and road wear particles (TRWPs) have become an increasing contamination concern because of their extensive distribution in the environment. A comprehensive overview of the methods for sampling, treatment and analysis of environmental samples for TRWPs (and their benefits and limitations) is lacking. We evaluate and critically assess the sampling, treatment and analysis methods previously reported for water, air, road dust and sediment/soil samples. We suggest research frameworks for studying TRWPs in these media. Microscopy and thermal analysis techniques such as scanning electron microscopy (with energy dispersive X-ray analysis), environmental scanning electron microscopy, 2-dimensional gas chromatography mass spectrometry and liquid chromatography with tandem mass spectrometry in the case of complex samples, are optimal methods for determination of the number and mass of TRWPs. Issues for further investigation and analysis recommendations are provided
Storm Response of Fluvial Sedimentary Microplastics
Full text linkUp to 80% of the plastics in the oceans are believed to have been transferred from river networks. Microplastic contamination of river sediments has been found to be pervasive at the global scale and responsive to periods of flooding. However, the physical controls governing the storage, remobilization and pathways of transfer in fluvial sediments are unknown. This means it is not currently possible to determine the risks posed by microplastics retained within the world’s river systems. This problem will be further exacerbated in the future given projected changes to global flood risk and an increased likelihood of fluvial flooding.Using controlled flume experiments we show that the evolution of the sediment bed surface and the flood wave characteristics controls the transition from rivers being ‘sinks’ to ‘sources’ of microplastics under flood conditions. By linking bed surface evolution with microplastic transport characteristics we show that similarities exist between granular transport phenomena and the behavior, and hence predictability, of microplastic entrainment during floods. Our findings are significant as they suggest that microplastic release from sediment beds can be managed by altering the timing and magnitude of releases in flow managed systems. As such it may be possible to remediate or remove legacy microplastics in future. <br/
“Old” and “new” contaminants and their management: learning from the past, looking to the future
No full textWithin the 50 year lifetime of the Society for Environmental Geochemistry and Health (SEGH), we have seen a number of contaminants transfer from being the wonder chemical of their day through to becoming current contaminants of concern. This is also true for a variety of emerging contaminants such as plastic microbeads, pharmaceutical residues, and fire retardant chemicals, amongst others. This thought piece discusses the risk associated with a range of these emerging contaminants, their global nature, how existing models and frameworks can be applied to deal with their impacts, and research and management gaps and challenges
A qualitative review of tsunamis in Hawaiʻi
No full textThe Hawaiian Islands have a long history of destructive and deadly tsunamis from both distant and local sources. Gaining a more detailed understanding of the historical record of tsunami impacts is a key step in reducing the vulnerability of coastal communities to tsunami inundation. This paper explores the history and prehistory of tsunamis in the Hawaiian archipelago, while proposing methods to narrow the gaps in our current understanding of their impacts. Fu
Data: FTIR spectra for particles in subsampled water samples from Southampton Water and analysed for microplastic content'
No full textFTIR spectra for particles identified in subsampled water samples taken in Southampton Water and analysed for microplastic content.
Data used in Chapter 3, Seasonal Variation of Microplastics in Southampton Water; from Stead (2021), Fate and Transport of Microplastics within Estuaries (PhD thesis). </span
Towards the application of electrokinetic remediation for nuclear site decommissioning
No full textContamination encountered on nuclear sites includes radionuclides as well as a range of non-radioactive co-contaminants, often in low-permeability substrates such as concretes or clays. However, many commercial remediation techniques are ineffective in these substrates. By contrast, electrokinetic remediation (EKR), where an electric current is applied to remove contaminants from the treated media, retains high removal efficiencies in low permeability substrates. Here, we evaluate recent developments in EKR for the removal of radionuclides in contaminated substrates, including caesium, uranium and others, and the current benefits and limitations of this technology. Further, we assess the present state of EKR for nuclear site applications using real-world examples, and outline key areas for future application
Electrokinetic Remediation - Where Next?
No full textIn this poster and presentation we will briefly introduce electrokinetic remediation (EKR; Fig. 1), a remediation technology that uses electricity to remove pollutants, such as fission products (137Cs, 90Sr), actinides (U-Am) and other radioactive and non-radioactive species, from contaminated nuclear site materials. We will also discuss its advantages, namely, that it is a versatile, low-energy (< 1 V.cm-1) and low-impact technique that operates effectively in low permeability substrates (clays, cements, etc.) which are difficult to remediate by conventional remediation technologies (e.g. chemical oxidation). Being a low-cost, in-situ remediation technology that can flexibly be applied on working sites, and in combination with other technologies, means EKR also aligns very well with emerging trends towards ‘low-impact’ remediation technologies, particularly on-site.
Using a recent case study or studies we will then show how EKR can be used to effectively remediate challenging substrates (clayey, organic-rich soils). We also show how the technology, currently restricted at scale, can in fact easily be scaled up to the pilot (metre-plus) size using in-situ iron barriering technology (ferric iron remediation and stabilisation, or FIRS). We will then very briefly highlight upcoming literature arising from this project, concluding with a “forward look” in which we briefly discuss progress towards the remaining TRANSCEND objectives, and where research into this rapidly developing technology should go next
Current technologies for the remediation of difficult-to-measure radionuclides at nuclear sites - 22224
No full textDifficult-to-measure radionuclides (DTMRs), defined by an absence of high-energy gamma emissions during decay, are problematic at nuclear sites. They are common contaminants at many facilities, including Hanford (WA, USA) and Sellafield (Cumbria, UK), that often have long half-lives and can potentially result in adverse health effects in humans, e.g. thyroid cancer from I-129 exposure. Effective remediation is therefore essential if nuclear site end-state targets for return to safe use are to be met. However, due to a lack of techniques for their in-situ detection, technologies designed to remediate these DTMRs are chronically underdeveloped and tend to be labour intensive and environmentally invasive (e.g. excavation), which can lead to further complications including elevated worker exposure doses during decommissioning. This, plus an emerging emphasis on sustainable remediation (e.g. ISO 18504, ASTM-E2876), means there is a renewed focus on less invasive technologies for radionuclide clean-up, and specifically for DTMRs.In this paper, we outline current technologies (Figure 1) for the remediation of DTMRs I-129, Tc-99, Sr-90 and H-3. These radionuclides have been selected based on their < 100 keV gamma emissions during decay, in combination with their high mobilities in groundwaters and prevalence at nuclear sites. We focus on the strengths and weaknesses of common remediation techniques that include ‘pump-and-treat’ (P&T) for contaminated groundwaters, in addition to permeable reactive barriers (PRBs) that are planted into spoilt land as engineered barrier systems to treat contaminated waters in-situ. Phytoremediation, which uses plants to extract, stabilise or degrade contamination, is also assessed as an emerging DTMR clean-up technology, with continuing development being driven by sustainability concerns and rising costs for traditional remediation methods. We supplement this discussion with examples from nuclear sites that are currently undergoing, or have previously undergone, decommissioning. We then conclude with our assessment on the future directions for these technologies and how they, either by themselves or in combination with others, may evolve over time to give more sustainable and less intrusive remediation options for assessors at nuclear or contaminated sites
Electrokinetic Remediation for Nuclear Site Decommissioning (RSC Radiochemistry YRM2021)
No full textElectrokinetic Remediation, EKR, is an electrochemical remediation technology that uses electricity to remove pollutants, such as fission products (137Cs, 90Sr), actinides (U-Am) and other radioactive and non-radioactive species, from contaminated nuclear site materials. It is a flexible and low-energy (< 1 V.cm-1) technique that operates effectively in low permeability substrates (cements, etc.) which are difficult to remediate by conventionally (e.g. chemical oxidation). It can be combined with renewable power inputs and operate in-situ, providing effective, safe, and sustainable solutions in which worker exposure to hazardous radiochemicals is minimized while high remediation efficiencies are retained. However, EKR is limited mostly to the laboratory or pilot scale for nuclear industry applications, with reliable, meter-plus scale studies in real operating environments still lacking.
Figure 1 – The EKR process, with precipitation of iron-rich phases shown when electrodes used are steel. Cation (C+) and anion (A–) movement with pH gradient, towards electrodes of opposing charge, is shown. Water electrolysis half-cell values are vs. SHE.
Here, we discuss EKR and its potential uses at nuclear sites at scale. We begin by summarizing the key advantages offered by EKR over other, conventional remediation methods and, from this, review how EKR, singly or in combination with other technologies, can be or has been applied practically. We also discuss our recent efforts (e.g. analysis by XRD, SEM/EDX, - and Mossbauer spectroscopies, etc.) to understand how a model system, using electrochemically precipitated Fe (Figure 1), influences sorption of selected contaminants in real nuclear materials. The target audience for this contribution cross-cuts academia and industry, developing fundamental concepts (electrochemistry, geochemistry) and applying them to the grand challenge of tackling the UK’s nuclear waste legacy
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