| 1. |
- Anderson, Robert, 1988, et al.
(författare)
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What's the point? The contribution of a sustainability view in contaminated site remediation
- 2018
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 630, s. 103-116
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Tidskriftsartikel (refereegranskat)abstract
- Decision support tools (DST) are often used in remediation projects to aid in the complex decision on how best to remediate a contaminated site. In recent years, the sustainable remediation concept has brought increased attention to the often-overlooked contradictory effects of site remediation, with a number of sustainability assessment tools now available. The aim of the present study is twofold: (1) to demonstrate how and when different assessment views affect the decision support outcome on remediation alternatives in a DST, and (2) to demonstrate the contribution of a full sustainability assessment. The SCORE tool was used in the analysis; it is based on a holistic multi-criteria decision analysis (MCDA) approach, assessing sustainability in three dimensions: environmental, social, and economic. Four assessment scenarios, compared to a full sustainability assessment, were considered to reflect different possible assessment views; considering public and private problem owner perspectives, as well as green and traditional assessment scopes. Four real case study sites in Sweden were analyzed. The results show that the decision support outcome from a full sustainability assessment most often differs to that of other assessment views, and results in remediation alternatives which balance trade-offs in most of the scenarios. In relation to the public perspective and traditional scope, which is seen to lead to the most extensive and expensive remediation alternatives, the trade-off is related to less contaminant removal in favour of reduced negative secondary effects such as emissions and waste disposal. Compared to the private perspective, associated with the lowest cost alternatives, the trade-off is higher costs, but more positive environmental and social effects. Generally, both the green and traditional assessment scopes miss out on relevant social and local environmental secondary effects which may ultimately be very important for the actual decision in a remediation project.
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| 2. |
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| 3. |
- Back, Erik, et al.
(författare)
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Mucosal blood flow in the remaining rectal stump is more affected by total than partial mesorectal excision in patients undergoing anterior resection : a key to understanding differing rates of anastomotic leakage?
- 2021
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Ingår i: Langenbeck's archives of surgery (Print). - : Springer. - 1435-2443 .- 1435-2451. ; 406:6, s. 1971-1977
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Anterior resection is the procedure of choice for tumours in the mid and upper rectum. Depending on tumour height, a total mesorectal excision (TME) or partial mesorectal excision (PME) can be performed. Low anastomoses in particular have a high risk of developing anastomotic leakage, which might be explained by blood perfusion compromise. A pilot study indicated a worse blood flow in TME patients in an open setting. The aim of this study was to further evaluate perianastomotic blood perfusion changes in relation to TME and PME in a predominantly laparoscopic context.METHOD: In this prospective cohort study, laser Doppler flowmetry was used to evaluate the perianastomotic colonic and rectal perfusion before and after surgery. The two surgical techniques were compared in terms of mean differences of perfusion units using a repeated measures ANOVA design, which also enabled interaction analyses between type of mesorectal excision and location of measurement. Anastomotic leakage until 90 days after surgery was reported for descriptive purposes.RESULTS: Some 28 patients were available for analysis: 17 TME and 11 PME patients. TME patients had a reduced blood perfusion postoperatively compared to PME patients in the aboral posterior area (mean difference: -57 vs 18 perfusion units; p = 0.010). An interaction between mesorectal excision type and anterior/posterior location was detected at the aboral level (p = 0.007). Two patients developed a minor leakage, diagnosed after discharge.CONCLUSION: Patients operated on using TME have a decreased blood flow in the aboral posterior quadrant of the rectum postoperatively compared to patients operated on using PME. This might explain differing rates of anastomotic leakage.TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02401100.
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| 4. |
- Back, Erik, et al.
(författare)
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Permanent stoma rates after anterior resection for rectal cancer : risk prediction scoring using preoperative variables
- 2021
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Ingår i: British Journal of Surgery. - : Oxford University Press. - 0007-1323 .- 1365-2168. ; 108:11, s. 1388-1395
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: A permanent stoma after anterior resection for rectal cancer is common. Preoperative counselling could be improved by providing individualized accurate prediction modelling.METHODS: Patients who underwent anterior resection between 2007 and 2015 were identified from the Swedish Colorectal Cancer Registry. National Patient Registry data were added to determine presence of a stoma 2 years after surgery. A training set based on the years 2007-2013 was employed in an ensemble of prediction models. Judged by the area under the receiving operating characteristic curve (AUROC), data from the years 2014-2015 were used to evaluate the predictive ability of all models. The best performing model was subsequently implemented in typical clinical scenarios and in an online calculator to predict the permanent stoma risk.RESULTS: Patients in the training set (n = 3512) and the test set (n = 1136) had similar permanent stoma rates (13.6 and 15.2 per cent). The logistic regression model with a forward/backward procedure was the most parsimonious among several similarly performing models (AUROC 0.67, 95 per cent c.i. 0.63 to 0.72). Key predictors included co-morbidity, local tumour category, presence of metastasis, neoadjuvant therapy, defunctioning stoma use, tumour height, and hospital volume; the interaction between age and metastasis was also predictive.CONCLUSION: Using routinely available preoperative data, the stoma outcome at 2 years after anterior resection for rectal cancer can be predicted fairly accurately.
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| 5. |
- Back, Pär-Erik, 1961
(författare)
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A model for estimating the value of sampling programs and the optimal number of samples for contaminated soil
- 2007
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Ingår i: Environmental Geology. - : Springer Science and Business Media LLC. - 0943-0105 .- 1432-0495. ; 52:3, s. 573-585
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Tidskriftsartikel (refereegranskat)abstract
- A model is presented for estimating the value of information of sampling programs for contaminated soil. The purpose is to calculate the optimal number of samples when the objective is to estimate the mean concentration. A Bayesian risk-cost-benefit decision analysis framework is applied and the approach is design-based. The model explicitly includes sample uncertainty at a complexity level that can be applied to practical contaminated land problems with limited amount of data. Prior information about the contamination level is modelled by probability density functions. The value of information is expressed in monetary terms. The most cost-effective sampling program is the one with the highest expected net value. The model was applied to a contaminated scrap yard in Goteborg, Sweden, contaminated by metals. The optimal number of samples was determined to be in the range of 16-18 for a remediation unit of 100 m(2). Sensitivity analysis indicates that the perspective of the decision-maker is important, and that the cost of failure and the future land use are the most important factors to consider. The model can also be applied for other sampling problems, for example, sampling and testing of wastes to meet landfill waste acceptance procedures.
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| 6. |
- Back, Par-Erik, et al.
(författare)
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Hållbarhetsanalys i avhjälpandeprocessen för förorenade områden - Principer och lärdomar från forskningsprojektet SAFIRE
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Forskningsprojektet SAFIRE genomfördes under åren 2015–2018. Projektets övergripande syfte var att utvärdera hur hållbarhetsbedömningar kan förbättra effektiviteten vid avhjälpande av föroreningsskador vid förorenade områden i Sverige. Bakgrunden till projektet var bland annat den låga saneringstakten i landet, de ofta höga kostnaderna för avhjälpande åtgärder samt åtgärdernas negativa effekter. Ett viktigt moment i avhjälpandeprocessen är att identifiera det åtgärdsalternativ som är bäst och det är rimligt att denna bedömning baseras på hållbarhet, vilket är det synsätt som tillämpats i forskningsprojektet. I arbetspaketet WP3, Incorporation of sustainability assessment in the remediation process, har lärdomarna från bland annat fallstudier använts för att utvärdera hållbarhetsanalysernas roll i avhjälpandeprocessen. Resultatet av detta arbete presenteras i denna rapport. En viktig slutsats är att arbetet med hållbarhetsanalyser måste komma in tidigt i avhjälpandeprocessen, redan i inledningen av huvudstudien, och hållbarhetsaspekterna bör återspeglas i de övergripande åtgärdsmål som formuleras. Som exempel måste de övergripande åtgärdsmålen lägga en grund för återfyllnadsmassornas kvalitet vid schaktsaneringar, så att en fungerande markmiljö återskapas. En annan slutsats är att det krävs ett iterativt arbetssätt för att en hållbarhetsanalys ska bli framgångsrik. Det innebär att det kan vara nödvändigt att backa till tidigare moment för att modifiera åtgärdsalternativ och samla in kompletterande information. Utgångspunkten i arbetet ska vara att den riskreduktion som krävs ska uppnås på ett så hållbart sätt som möjligt. Det gäller att vara observant på att samtliga efterbehandlingsalternativ verkligen uppfyller kravet på riskreduktion. För flera moment i huvudstudien behöver vägledningar tas fram, med fokus på hållbarhet. Detta gäller bland annat hur övergripande åtgärdsmål formuleras och hur en åtgärdsutredning bör utformas. Tydligare vägledning i dessa och liknande frågor kan i förlängningen bidra till mer hållbara efterbehandlingsåtgärder.
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| 7. |
- Back, Pär-Erik, 1961, et al.
(författare)
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Markmiljöns skyddsvärde – En härledning med utgångspunkt i miljöetik och lagstiftning
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Vid riskbedömning av förorenade områden ska riskerna som föroreningen utgör bedömas för olika skyddsobjekt, främst människor, markmiljö, grund- och ytvatten. I fördjupade riskbedömningar kan det även vara aktuellt att bestämma lämpliga skyddsnivåer för skyddsobjekten. Till vilken nivå vi väljer att skydda ett objekt beror i hög grad på objektets skyddsvärde. Vad detta skyddsvärde består av och hur stort det anses vara beror i sin tur på vem det är som gör värderingen och vilket miljöetiskt synsätt som tillämpas. När skyddsobjektet markmiljö ska värderas uppstår ofta många frågor och oenigheten mellan olika aktörer kan ibland vara stor.Syftet med publikationen är att tydliggöra vad som avses med begreppet markmiljöns skyddsvärde och beskriva vad det består av. Olika miljöetiska synsätt kan leda till att vår markmiljö värderas olika högt beroende på vem som utför värderingen. I syfte att skapa en gemensam grund för denna typ av värderingar har vi här valt att utgå från den miljöetik som ligger till grund för vår miljölagstiftning. Målet med publikationen är att presentera en härledning av markmiljöns skyddsvärde och ge en grund för hur man kan resonera kring flera av de besvärliga frågor som ställs beträffande skyddet av markmiljön.Rapporten innehåller också en allmän diskussion av skyddsvärdet men beskriver inte konkret hur markmiljön bör värderas vid ett enskilt objekt. Publikationen är med andra ord ingen vägledning i den bemärkelsen att den är direkt tillämpbar för värdering i verkliga projekt. Vår förhoppning är istället att publikationen kommer att utgöra en viktig grund för arbetet med att ta fram framtida vägledningsmaterial för ekologisk riskbedömning samt riskvärdering.
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| 8. |
- Back, Pär-Erik, 1961
(författare)
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On Uncertainty and Data Worth in Decision Analysis for Contaminated Land
- 2003
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Contaminated soil and groundwater is a problem that has received increased attention in the last decade. Decision-making about investigation strategies, protective actions, and remedial actions is based on sparse and uncertain information, primarily data of contaminant concentrations and geological information. Because of limited economical resources, cost-efficient decisions must be made. Risk-based decision analysis is a tool for evaluating the cost-efficiency of different decision alternatives. Identification of cost-efficient site investigations can be performed by applying data worth analysis. In such an analysis, the value of additional sample data is compared to sampling cost and if the data worth is larger than the cost it will be worthwhile to carry out the sampling. Because environmental samples are uncertain, this uncertainty should be considered in the analysis. An approach for estimation of uncertainty in soil sampling is presented. It is based on the sampling theory for particulate materials developed for the mining industry. The sample uncertainty is broken down into eight basic types of uncertainty and variability. An application of the methodology is presented for the problem of soil sampling with a drill auger. The result indicate that the uncertainty in sample data can easily be in the range of 30-40 %. The sampling uncertainty is believed to be much more important that the analytical uncertainty. A methodology for including sample uncertainty in data worth analysis is presented. It is based on a Bayesian approach to data worth. The sampling objective is to estimate the mean concentration at a site. A MathCad computer application for the calculations is supplied. An application of the data worth estimation procedure is presented for a sampling problem at a former Ferro-alloy work in Gullspång, Sweden. A conclusion is that prior estimates of contaminant concentrations may have a significant impact on the result, as well as estimates of failure cost. It is recommended to use different estimates of failure cost to study its influence. Results also indicate that when sample uncertainty is increased, the expected net value of the sampling program will decrease moderately and relatively constant. In situations where contamination has not yet occurred, cost-efficient protective actions need to be identified to combat environmental risks. A methodology for selecting costefficient protective actions for water supplies along railways has been developed. The risk object is railway transport of dangerous goods. Also for this problem, estimation of failure cost is believed to be important for the result. The need for additional development of the methodology is identified. Estimation of uncertainty in soil sampling can be improved and the described theory extended. The methodology for data worth analysis for contaminated land should be extended to take additional sampling objectives into account. contaminated land, data worth, decision analysis, risk, sampling, uncertainty
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| 9. |
- Back, Pär-Erik, 1961, et al.
(författare)
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Value of information analysis for site investigation programs accounting for variability, uncertainty and scale effects with the Aspo HRL prototype repository as an example
- 2009
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Ingår i: International Journal of Rock Mechanics and Minings Sciences. - : Elsevier BV. - 1365-1609. ; 46:5, s. 896-904
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Tidskriftsartikel (refereegranskat)abstract
- An important feature of underground projects is the early site investigations, performed as a means to identify and quantify hazards. A methodology is presented for identifying the most cost-effective investigation program among a set of alternatives. Methodologies are presented for both investigation of thermal conductivity in hard rock and collection of rock mechanic data for stress induced spalling problems. The cost-effectiveness of an investigation program is estimated by means of value of information analysis (VOIA). Each investigation program of thermal conductivity is associated with uncertainty due to natural variability and lack of knowledge. These uncertainties are taken into account in a simulation model with the aim to estimate the distribution of thermal conductivity values at different scales. The output is a set of thermal conductivity values from which a design parameter can be estimated. The simplest measure of the value of a site investigation is the expected reduction of uncertaintyofthedesignparameter. The methodology is demonstrated with a case study for the prototype nuclear waste repository at Aspo Hard Rock Laboratory, Sweden. A set of four investigation programs for thermal conductivity were evaluated, and the most effective one identified. The application illustrates that an investigation program may supply very different value to a project, depending on how the objective of the investigation is defined. This is demonstrated by using two different objectives and comparing the results. Practical applications of the methodology on both thermal properties and rock mechanics are discussed, with emphasis on site investigations performed by the Swedish Nuclear Fuel and Waste Management (SKB). (C) 2009 Elsevier Ltd. All rights reserved.
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| 10. |
- Back, Pär-Erik, 1961
(författare)
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Value of Information Analysis for Site Investigations in Remediation Projects
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Site investigations of contaminated land are associated with high costs. From a societal point of view, just enough economic resources should be spent to allow societys limited resources to be allocated optimally to sustainable development. The solution is to design cost-effective investigation programmes, which can be performed using Value of Information Analysis (VOIA). The principle is to compare the expected benefit at present state of knowledge with the benefit that is expected after an investigation has been performed. Statistical methods are used to calculate the expected change, i.e. the value of the investigation. The main strength of the VOIA process is that it promotes clear thinking and forces the decision-maker to reflect on issues that otherwise would be ignored.A general framework for VOIA of site investigations is presented. The framework consists of seven modules: (1) the land use scenario, (2) the objective of investigation, (3) a conceptual site model, (4) a data collection module, (5) a prior information module, (6) an uncertainty reduction module, and (7) a decision model. The decision model is based on Bayesian risk-cost-benefit decision analysis. The result is an estimate of the value of an investigation programme, and for specific problems, the optimal number of samples. The framework can be applied on three complexity levels, where the value is expressed as: (a) the uncertainty reduction, (b) the quotient of uncertainty reduction and investigation cost, or (c) the expected monetary value. VOIA models were developed for investigations at early phases of a project, and for sampling during the later remediation phase. The models were applied in case-studies and the applications illustrate that the investigation objective, the land use, and the benefit of remediation have a major impact on the results. The main contributions of this thesis are: (1) a general framework for VOIA of site investigations in remediation projects, (2) a toolkit of VOIA models for practical application, and (3) a knowledge base of strengths and weaknesses of the methodology, including recommendations of development.
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