Fractionation of potentially toxic elements in urban soils from five European cities by means of a harmonised sequential extraction procedure

The revised (four-step) BCR sequential extraction procedure has been applied to fractionate the chromium, copper, iron, manganese, nickel, lead and zinc contents in urban soil samples from public-access areas in five European cities. A preliminary inter-laboratory comparison was conducted and showed that data obtained by different laboratories participating in the study were sufficiently harmonious for comparisons to be made between cities and land types (e.g. parks, roadside, riverbanks, etc.). Analyte recoveries by sequential extraction, with respect to direct aqua regia digestion, were generally acceptable (100 ± 15%). Iron, nickel and, at most sites, chromium were found mainly in association with the residual phase of the soil matrix. Copper was present in the reducible, oxidisable and residual fractions, whilst zinc was found in all four sequential extracts. Manganese was strongly associated with reducible material as, in some cities, was lead. This is of concern because high lead concentrations were present in some soils (>500 mg kg−1) and the potential exists for remobilisation under reducing conditions. As would be expected, extractable metal contents were generally highest in older, more heavily industrialised cities. Copper, lead and zinc showed marked (and often correlated) variations in concentrations between sites within the same city whereas manganese and, especially, iron, did not. No overall relationships were, however, found between analyte concentrations and land use, nor between analyte partitioning and land use

The development and validation of a scoring tool to predict the operative duration of elective laparoscopic cholecystectomy

Background: The ability to accurately predict operative duration has the potential to optimise theatre efficiency and utilisation, thus reducing costs and increasing staff and patient satisfaction. With laparoscopic cholecystectomy being one of the most commonly performed procedures worldwide, a tool to predict operative duration could be extremely beneficial to healthcare organisations. Methods: Data collected from the CholeS study on patients undergoing cholecystectomy in UK and Irish hospitals between 04/2014 and 05/2014 were used to study operative duration. A multivariable binary logistic regression model was produced in order to identify significant independent predictors of long (> 90 min) operations. The resulting model was converted to a risk score, which was subsequently validated on second cohort of patients using ROC curves. Results: After exclusions, data were available for 7227 patients in the derivation (CholeS) cohort. The median operative duration was 60 min (interquartile range 45–85), with 17.7% of operations lasting longer than 90 min. Ten factors were found to be significant independent predictors of operative durations > 90 min, including ASA, age, previous surgical admissions, BMI, gallbladder wall thickness and CBD diameter. A risk score was then produced from these factors, and applied to a cohort of 2405 patients from a tertiary centre for external validation. This returned an area under the ROC curve of 0.708 (SE = 0.013, p  90 min increasing more than eightfold from 5.1 to 41.8% in the extremes of the score. Conclusion: The scoring tool produced in this study was found to be significantly predictive of long operative durations on validation in an external cohort. As such, the tool may have the potential to enable organisations to better organise theatre lists and deliver greater efficiencies in care

Online computer-mediated decision-making for sustainable environmental management

This thesis describes emerging European Union challenges for environmental justice: public participation with transparent decision-making; and knowledge transfer of complex scientific information. It describes the Delphi technique, a pen-and-paper decision support framework developed during the late 1950s and 1960s and its potential to meet environmental justice challenges, if coupled with internet-based computer technologies; online computer mediated decision making (OCMDM). Through various case studies, mainly with one group of soil experts, a long term assessment of OCMDM is presented. This thesis argues that OCMDM provides a technologically flexible, relatively inclusive and efficient framework for discourse capture. However, from a social perspective, OCMDM is far from universally popular, mirroring long-held views of traditional pen-and-paper-based Delphis. At this time, the tool could not be recommended as a transferable panacea for public consultation. Nevertheless, a long-term study of user group engagement with the tool identifies significant utility for conflict resolution, with scope for application within contentious decision-making arenas, if utilised sparingly and thoughtfully. Criteria for successful 'real-world' acceptance of application and research with the tool are provided, together with examples of real-world decision-making arenas that meet them. Through analysis of participants' perceptions, a tantalising glimpse of potentially complex fractal-based decision processes is offered: honing and spiraling towards an ever-refining definition of a truth. This study suggests that this singular decision is itself only part of other archetypal honing-spiraling mechanisms of decision-making, either objectively or metaphorically; each of differing attractions and repulsion to an end user. By identifying some of these fundamental rules of participation, this study provides an opportunity to explore human interaction and decision-making with greater accuracy. There is considerable potential to eliminate most, if not all, OCMDM participant concerns.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

The influence of anthropogenic and natural geochemical factors on urban soil quality variability: a comparison between Glasgow, UK and Aveiro, Portugal

As part of a harmonised assessment of urban soils (http://www.urbsoil.paisley.ac.uk), we investigated the variability of metal content in soils from Aveiro (Portugal) and Glasgow (UK). Samples were collected from parks and other public open spaces in each city. Metal content (Al, Ca, Cr, Cu, Fe, Mn, Ni, Pb and Zn) and basic soil parameters (texture, CEC, pH, organic matter) were determined and data investigated using principal component analysis (PCA). The two cities differ in absolute levels of metal content reflecting industrial and historical development. Factors identified by PCA included anthropogenic (Cu, Pb, Zn), soil properties and geology, which explain variability when data were assessed based on metal content, soil properties and land use. This study highlights the contribution from geological background even in strongly urbanised environments

Quality and comparability of measurement of potentially toxic elements in urban soils by a group of European laboratories

A study has been conducted to assess the quality and comparability of measurement of aqua-regia-soluble cadmium, chromium, copper, iron, manganese, nickel, lead, and zinc in urban soils within a small cohort of European research laboratories specializing in soil science or environmental analytical chemistry. An initial survey indicated that highly variable levels of analytical quality control (e.g. use of certified reference materials) were routinely implemented in participant laboratories. When a set of soil samples-differing in metal contents and in characteristics such as pH and organic-matter content-were exchanged and analysed, approximately 20% of results differed from target values by more than 25%. A principal-component analysis was applied to data for chromium, copper, nickel, lead, and zinc, and proved successful in assessing overall laboratory performance. The study indicates that greater prominence needs to be given to quality assurance and control if comparable data are to be generated in international, collaborative research projects