Mobility of antimony, arsenic and lead at a former mine, Glendinning, Scotland

Elevated concentrations of antimony (Sb), arsenic (As) and lead (Pb) in upland organic-rich soils have resulted from past Sb mining activities at Glendinning, southern Scotland. Transfer of these elements into soil porewaters was linked to the production and leaching of dissolved organic matter and to leaching of spoil material. Sb was predominantly present in truly dissolved (< 3 kDa) forms whilst As and Pb were more commonly associated with large Fe-rich/organic colloids. The distinctive porewater behaviour of Sb accounts for its loss from deeper sections of certain cores and its transport over greater distances down steeper sections of the catchment. Although Sb and As concentrations decreased with increasing distance down a steep gully from the main spoil heap, elevated concentrations (~ 6-8 and 13-20 μg L− 1, respectively) were detected in receiving streamwaters. Thus, only partial attenuation occurs in steeply sloping sections of mining-impacted upland organic-rich soils and so spoil-derived contamination of surface waters may continue over time periods of decades to centuries

Strategies for producing biochars with minimum PAH contamination

With the aim to develop initial recommendations for production of biochars with minimal contamination with polycyclic aromatic hydrocarbons (PAHs), we analysed a systematic set of 46 biochars produced under highly controlled pyrolysis conditions. The effects of the highest treatment temperature (HTT), residence time, carrier gas flow and typical feedstocks (wheat / oilseed rape straw pellets (WSP), softwood pellets (SWP)) on 16 US EPA PAH concentration in biochar were investigated. Overall, the PAH concentrations ranged between 1.2 and 100 mg kg-1. On average, straw-derived biochar contained 5.8 times higher PAH concentrations than softwood-derived biochar. In a batch pyrolysis reactor, increasing carrier gas flow significantly decreased PAH concentrations in biochar; in case of straw, the concentrations dropped from 43.1 mg kg-1 in the absence of carrier gas to 3.5 mg kg-1 with a carrier gas flow of 0.67 L min-1; for woody biomass PAHs concentrations declined from 7.4 mg kg-1 to 1.5 mg kg-1 with the same change of carrier gas flow. In the temperature range of 350-650°C the HTT did not have any significant effect on PAH content in biochars, irrespective of feedstock type, however, in biochars produced at 750°C the PAH concentrations were significantly higher. After detailed investigation it was deduced that this intensification in PAH contamination at high temperatures was most likely down to the specifics of the unit design of the continuous pyrolysis reactor used. Overall, it was concluded that besides PAH formation, vaporisation is determining the PAH concentration in biochar. The fact that both of these mechanisms intensify with pyrolysis temperature (one increasing and the other one decreasing the PAH concentration in biochar) could explain why no consistent trend in PAH content in biochar with temperature has been found in the literature

An Investigation of Actinide Interactions With Humic Substances

Saltmarsh and intertidal areas in SW Scotland and NW England receive inputs of natural and anthropogenic radionuclides from a number of sources. Discharges of low level liquid radioactive waste from the Sellafield nuclear fuel reprocessing plant, with maximum releases in the 1970s, have resulted in contamination of the offshore sediment in the proximity of the discharge point with the anthropogenic nuclides, 238Pu, 239u, 240Pu and 241Am and 237Np. Dispersal and redeposition of the contaminated sediment has resulted in continuous input of these nuclides to soils and sediments in coastal areas over the past 40 years which will continue for the forseeable future. Natural decay series radionuclides are subject to similar deposition processes following their discharge from a phosphate refinery at Whitehaven. Additionally, natural decay series radionuclides occur at enhanced levels in saltmarsh sediments of the Solway Firth as a consequence of deposition from natural uranium mineralisations. Previous studies, involving sequential extraction of components of soils and sediments, have highlighted the importance of the organic fraction in binding significant proportions of actinides present in these environments. This thesis presents a study of three locations - a saltmarsh in SW Scotland, a floodplain soil (R. Esk, W Cumbria) and a highly organic soil on the bank of the R. Esk, W Cumbria. The saltmarsh sediments and the Esk soils vary in the degree of marine inundation experienced and provide contrasting environmental conditions which in turn affect actinide geochemistry. Gel filtration chromatography, FTIR, UV and Fluorescence spectroscopy, alpha spectrometry and ICP-MS were used to investigate the influential role of the organic fraction, and in particular humic substances, in determining actinide behaviour. Specifically, these techniques were used to investigate humic properties including structural characteristics and actinide binding ability. An important part of this work involved the evaluation of traditional extraction methodology and, following the observation that humic substances were irreversibly altered during the separation of humic and fulvic acids, both in terms of their actinide binding capacity and chemical characteristics, the application of new methodology was developed to minimise these etfects. Conclusions from this study are as follows: i) the sum of properties of humic acid and fulvic acid is not equal to those of humic substances: ii) humic substances from diverse locations are compositionally different retlecting the variations in the source of the precursor material, iii ) humic substances comprise only a minor component of the total soil mass but account disproponionately for a significant amount of the actinide binding capacity the soil or sediment, iv) gel chromatographic separation of humic substances provides fractions which are less heterogeneous than the bulk material , v) gel fractionation is unsuitable for size determination of humic materials since certain humic components are retarded by the gel resulting in their elution at greater volumes than proposed purely on the basis of size, VI) characterisation of fractions of humic substances showed that they vary in chemical composition and in their actinide binding capacity. This provided evidence of discrete associations of actinide elements with fractions of humic substances indicating that a single parameter describing their interaction with the bulk humic material is inadequate, vii) characterisation of fractions also shows that actinide associations with humic material are influenced by the composition and the degree of diagenetic alteration of the humic material. In summary, this study has provided evidence of discrete associations of actinide elements with fractions of humic substances and that different components of the humic fraction have widely varying actinide binding capacities. The chemical characteristics of these molecules are vitally important in determining the mobility of these species in the environment

Investigating the hydration of C3A in the presence of the potentially toxic element chromium–a route to remediation?

Pollution by hexavalent chromium is a growing, global problem. Its presence in public water systems is often the result of industrial activities, both past and present. In this study, tricalcium aluminate (C3A, Ca(3)Al(2)O(6)) is added to solutions of varying concentrations of potassium chromate (K(2)CrO(4)) and samples of both the solid and liquid are taken at various time intervals to monitor the removal of chromium from the solutions. Solution concentrations of 0.2 M, 0.1 M, 0.02 M, and 0.01 M are used, and the chromium concentration is found to reduce in all cases. For the 0.02 M solution the chromium concentration is reduced from 1040 ppm to 3.1 ppm in 1 week, and the chromium concentration of the 0.01 M solution is reduced from 520 ppm to 0.26 ppm in only one day of reaction with the C3A. The chromium removed from solution is identified in the solid products, which were fully characterised as being a mixture of ettringite (Ca(6)[Al(OH)(6)](2)(CrO(4))(3)·26H(2)O) and monochromate (Ca(4)[Al(OH)(6)](2)CrO(4)·8H(2)O) phases from analysis of Powder X-ray Diffraction and Fourier Transform Infrared Spectroscopy data. The work presented here is a proof of concept study to investigate C3A as a potential material for the removal of hexavalent chromium from solution. The results from this study are initial steps towards development of this as a technology for hexavalent chromium remediation

A microanalytical study of iron, aluminium and organic matter relationships in soils with contrasting hydrological regimes

It is recognised that interactions between mineral oxides and soil organic matter (SOM) are an important factor in the stabilisation of soil organic carbon (SOC). The nature of these interactions is particularly complex in gleyed soils that experience periodic waterlogging and changeable redox conditions. This study explores the complex patterns of iron (Fe) (hydr)oxides and SOM in three soils with contrasting hydrological regimes (Gleysol, Stagnosol and Cambisol). Micromorphological examination of undisturbed soil thin sections was teamed with SEM-EDS analysis and sequential dissolution of Fe pedofeatures to gain a better understanding of the mechanisms involved in SOM stabilisation by mineral oxides. All soils contained a diverse range of particulate SOM forms and Fe pedofeatures; the degree of impregnation of the Fe pedofeatures was found to increase with depth and a strong correlation between the presence of SOM and Fe pedofeatures was found to exist through all soils. Weakly crystalline Fe (hydr)oxides were found in association with partially degraded tissue residues and amorphous fine organic matter (OM). Strongly crystalline Fe (hydr)oxides were found in all impregnative Fe pedofeatures and high Fe/C ratios suggested precipitative processes rather than sorption dominate SOC sequestration in these features. In addition, at the core of some strongly impregnated Fe nodules, occluded well preserved organic tissues were identified. The study highlights the range of processes and complexity involved in SOC sequestration over mm to cm scales and untangling this complexity is vital to understanding and modelling terrestrial C fluxes. Whilst the methods used here are not without their complications, the value of micro-scale studies of undisturbed soil thin sections is clearly demonstrated

Laser desorption/ionization coupled to FT-ICR mass spectrometry for studies of natural organic matter

Laser desorption/ionization (LDI) was investigated as an ionization method for Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) studies of natural organic matter (NOM). Using International Humic Substances Society standards, Suwannee River fulvic acid (SRFA) and Suwannee River natural organic matter (SRNOM), LDI was found to ionize a very similar set of compounds (>90% of molecular formulas identity) to the matrix assisted laser desorption/ionization (MALDI), while producing higher quality spectra. A comparison of electrospray ionization (ESI) and LDI spectra showed that different types of compounds are ionized by these methods with only 9.9% of molecular formulas common to both. The compounds ionized by LDI/MALDI belong to low oxygen classes (maximum number of species for O7–O9), while ESI compounds belong to higher oxygen classes (maximum number of species for O14–O16). Compounds ionized by LDI can be classified as aliphatic, aromatic, and condensed aromatics in approximately equal measure, while aliphatic compounds dominated the ESI spectra of SRFA. In order to maximize the coverage of molecular species, LDI, as a particularly convenient and readily deployable ionization method, should be used routinely in combination with other ionization methods, such as ESI, for FTICR MS studies of NOM

Dissemination and implementation science training needs: Insights from practitioners and researchers

INTRODUCTION: Dissemination and implementation research training has great potential to improve the impact and reach of health-related research; however, research training needs from the end user perspective are unknown. This paper identifies and prioritizes dissemination and implementation research training needs. METHODS: A diverse sample of researchers, practitioners, and policymakers was invited to participate in Concept Mapping in 2014–2015. Phase 1 (Brainstorming) gathered participants' responses to the prompt: To improve the impact of research evidence in practice and policy settings, a skill in which researchers need more training is… The resulting statement list was edited and included subsequent phases. Phase 2 (Sorting) asked participants to sort each statement into conceptual piles. In Phase 3 (Rating), participants rated the difficulty and importance of incorporating each statement into a training curriculum. A multidisciplinary team synthesized and interpreted the results in 2015–2016. RESULTS: During Brainstorming, 60 researchers and 60 practitioners/policymakers contributed 274 unique statements. Twenty-nine researchers and 16 practitioners completed sorting and rating. Nine concept clusters were identified: Communicating Research Findings, Improve Practice Partnerships, Make Research More Relevant, Strengthen Communication Skills, Develop Research Methods and Measures, Consider and Enhance Fit, Build Capacity for Research, and Understand Multilevel Context. Though researchers and practitioners had high agreement about importance (r =0.93) and difficulty (r =0.80), ratings differed for several clusters (e.g., Build Capacity for Research). CONCLUSIONS: Including researcher and practitioner perspectives in competency development for dissemination and implementation research identifies skills and capacities needed to conduct and communicate contextualized, meaningful, and relevant research

Relating microfeatures of soil organic matter to C stabilisation: optical microscopy, SEM-EDS, abiotic oxidation

We investigated the relationships between microscale distribution of soil organic matter (SOM) features and their stability by combining optical microscopy, SEM-EDS analysis and NaClO oxidation of soil thin sections on five soils from Harwood Forest in Northumberland (UK) differently affected by water stagnation. Plant organs at different stages of decomposition and amorphous organic matter were observed by optical microscopy in all samples. SOM microfeature distribution, size of SOM features and the relation with the C-to-N ratio suggested that amorphous features could be the end-products of organ transformation. SEM-EDS elemental analysis showed that amorphous material had higher Si/C, Al/C and Fe/C molar ratios than organs, clearly pointing to interactions with the soil inorganic phases, which contributed to SOM stabilisation. Soil porosity coupled with water stagnation seemed to affect the Fe-SOM interactions as a greater proportion of small water retention pores (10- 50 μm) was associated with higher abundance of Fe-rich amorphous organic features. The higher chemical stability of amorphous features was confirmed by oxidation. After NaClO treatment, organs were almost totally removed, while amorphous organic material was less affected both morphologically and chemically. Our results demonstrate that in water-affected soils local environment defined by the pore system affects the distribution of SOM microfeatures and that the highest resistance to oxidation of the amorphous features is attributable to the formation of organic-inorganic associations. The proposed combined approach seems to be a promising mean to investigate SOM dynamics by relating features to stability

FAK Deletion Promotes p53-Mediated Induction of p21, DNA-Damage Responses and Radio-Resistance in Advanced Squamous Cancer Cells

Focal adhesion kinase (FAK) is a cytoplasmic tyrosine kinase that is elevated in a variety of human cancers. While FAK is implicated in many cellular processes that are perturbed in cancer, including proliferation, actin and adhesion dynamics, polarisation and invasion, there is only some limited information regarding the role of FAK in radiation survival. We have evaluated whether FAK is a general radio-sensitising target, as has been suggested by previous reports. We used a clean genetic system in which FAK was deleted from mouse squamous cell carcinoma (SCC) cells (FAK −/−), and reconstituted with exogenous FAK wild type (wt). Surprisingly, the absence of FAK was associated with increased radio-resistance in advanced SCC cells. FAK re-expression inhibited p53-mediated transcriptional up-regulation of p21, and a sub-set of other p53 target genes involved in DNA repair, after treatment with ionizing radiation. Moreover, p21 depletion promoted radio-sensitisation, implying that FAK-mediated inhibition of p21 induction is responsible for the relative radio-sensitivity of FAK-proficient SCC cells. Our work adds to a growing body of evidence that there is a close functional relationship between integrin/FAK signalling and the p53/p21 pathway, but demonstrates that FAK's role in survival after stress is context-dependent, at least in cancer cells. We suggest that there should be caution when considering inhibiting FAK in combination with radiation, as this may not always be clinically advantageous