| 1. |
- Amir Heidari, Payam, 1989, et al.
(author)
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A state-of-the-art model for spatial and stochastic oil spill risk assessment: A case study of oil spill from a shipwreck
- 2019
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In: Environment International. - : Elsevier BV. - 0160-4120 .- 1873-6750. ; 126, s. 309-320
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Journal article (peer-reviewed)abstract
- Oil spills are serious environmental issues that potentially can cause adverse effects on marine ecosystems. In some marine areas, like the Baltic Sea, there is a large number of wrecks from the first half of the 20th century, and recent monitoring and field work have revealed release of oil from some of these wrecks. The risk posed by a wreck is governed by its condition, hazardous substances contained in the wreck and the state of the surrounding environment. Therefore, there is a need for a common standard method for estimating the risks associated with different wrecks. In this work a state-of-the-art model is presented for spatial and stochastic risk assessment of oil spills from wrecks, enabling a structured approach to include the complex factors affecting the risk values. A unique feature of this model is its specific focus on uncertainty, facilitating probabilistic calculation of the total risk as the integral expected sum of many possible consequences. A case study is performed in Kattegat at the entrance region to the Baltic Sea to map the risk from a wreck near Sweden. The developed model can be used for oil spill risk assessment in the marine environment all over the world.
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| 2. |
- Bergion, Viktor, 1986, et al.
(author)
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Accounting for Unexpected Risk Events in Drinking Water Systems
- 2021
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In: Exposure and Health. - : Springer Science and Business Media LLC. - 2451-9685 .- 2451-9766. ; 13:1, s. 15-31
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Journal article (peer-reviewed)abstract
- Unexpected risk events in drinking water systems, such as heavy rain or manure spill accidents, can cause waterborne outbreaks of gastrointestinal disease. Using a scenario-based approach, these unexpected risk events were included in a risk-based decision model aimed at evaluating risk reduction alternatives. The decision model combined quantitative microbial risk assessment and cost–benefit analysis and investigated four risk reduction alternatives. Two drinking water systems were compared using the same set of risk reduction alternatives to illustrate the effect of unexpected risk events. The first drinking water system had a high pathogen base load and a high pathogen log10 reduction in the treatment plant, whereas the second drinking water system had a low pathogen base load and a low pathogen Log10 reduction in the treatment plant. Four risk reduction alternatives were evaluated on their social profitability: (A1) installation of pumps and back-up power supply, to remove combined sewer overflows; (A2) installation of UV treatment in the drinking water treatment plant; (A3) connection of 25% of the OWTSs in the catchment area to the WWTP; and (A4) a combination of A1–A3. Including the unexpected risk events changed the probability of a positive net present value for the analysed alternatives in the decision model and the alternative that is likely to have the highest net present value. The magnitude of the effect of unexpected risk events is dependent on the local preconditions in the drinking water system. For the first drinking water system, the unexpected risk events increase risk to a lesser extent compared to the second drinking water system. The main conclusion was that it is important to include unexpected risk events in decision models for evaluating microbial risk reduction, especially in a drinking water system with a low base load and a low pathogen log10 reduction in the drinking water treatment plant.
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| 3. |
- Bergion, Viktor, 1986, et al.
(author)
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Economic Valuation for Cost–Benefit Analysis of Health Risk Reduction in Drinking Water Systems
- 2020
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In: Exposure and Health. - : Springer Science and Business Media LLC. - 2451-9685 .- 2451-9766. ; 12:1, s. 99-110
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Journal article (peer-reviewed)abstract
- Microbial risk mitigation measures in drinking water systems aiming at preventing gastrointestinal disease can provide substantial societal health benefits if implemented properly. However, the procedure of including and monetising the health benefits in cost–benefit analysis (CBA) has been somewhat scattered and inconsistent in the literature, and there is a need for a comparison of available methods. First, through a literature review, we identified the methods to include health benefits in decision support and to monetise these benefits in CBA. Second, we applied the identified health valuation methods in a case study. In the case study, we investigated if changing the health valuation method could change the rank order of the decision alternatives’ net present values. In the case study a risk-based decision model that combined quantitative microbial risk assessment and CBA was used. Seven health valuation methods were identified, each of them including different aspects of health benefits. The results of the case study showed that the choice of the health valuation method can change the rank order of decision alternatives with respect to their net present values. These results highlight the importance of choosing an appropriate health valuation method for the specific application. Although this study focused on the drinking water context, the identified health valuation methods can be applied in any decision support context, provided that input in terms of the health risk reduction is available.
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| 4. |
- Bergion, Viktor, 1986, et al.
(author)
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Hydrological modelling in a drinking water catchment area as a means of evaluating pathogen risk reduction
- 2017
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In: Journal of Hydrology. - : Elsevier BV. - 0022-1694. ; 544, s. 74-85
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Journal article (peer-reviewed)abstract
- Waterborne outbreaks of gastrointestinal diseases are of great concern to drinking water producers and can give rise to substantial costs to the society. The World Health Organisation promotes an approach where the emphasis is on mitigating risks close to the contamination source. In order to handle microbial risks efficiently, there is a need for systematic risk management. In this paper we present a framework for microbial risk management of drinking water systems. The framework incorporates cost-benefit analysis as a decision support method. The hydrological Soil and Water Assessment Tool (SWAT) model, which was set up for the Stäket catchment area in Sweden, was used to simulate the effects of four different mitigation measures on microbial concentrations. The modelling results showed that the two mitigation measures that resulted in a significant (p
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| 5. |
- Bergion, Viktor, 1986, et al.
(author)
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Risk-based cost-benefit analysis for evaluating microbial risk mitigation in a drinking water system
- 2018
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In: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 132, s. 111-123
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Journal article (peer-reviewed)abstract
- Waterborne outbreaks of gastrointestinal diseases can cause large costs to society. Risk management needs to be holistic and transparent in order to reduce these risks in an effective manner. Microbial risk mitigation measures in a drinking water system were investigated using a novel approach combining probabilistic risk assessment and cost-benefit analysis. Lake Vomb in Sweden was used to exemplify and illustrate the risk-based decision model. Four mitigation alternatives were compared, where the first three alternatives, A1-A3, represented connecting 25, 50 and 75%, respectively, of on-site wastewater treatment systems in the catchment to the municipal wastewater treatment plant. The fourth alternative, A4, represented installing a UV-disinfection unit in the drinking water treatment plant. Quantitative microbial risk assessment was used to estimate the positive health effects in terms of quality adjusted life years (QALYs), resulting from the four mitigation alternatives. The health benefits were monetised using a unit cost per QALY. For each mitigation alternative, the net present value of health and environmental benefits and investment, maintenance and running costs was calculated. The results showed that only A4 can reduce the risk (probability of infection) below the World Health Organization guidelines of 10−4 infections per person per year (looking at the 95th percentile). Furthermore, all alternatives resulted in a negative net present value. However, the net present value would be positive (looking at the 50th percentile using a 1% discount rate) if non-monetised benefits (e.g. increased property value divided evenly over the studied time horizon and reduced microbial risks posed to animals), estimated at 800–1200 SEK (€100–150) per connected on-site wastewater treatment system per year, were included. This risk-based decision model creates a robust and transparent decision support tool. It is flexible enough to be tailored and applied to local settings of drinking water systems. The model provides a clear and holistic structure for decisions related to microbial risk mitigation. To improve the decision model, we suggest to further develop the valuation and monetisation of health effects and to refine the propagation of uncertainties and variabilities between the included methods.
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| 6. |
- Dahlqvist, Peter, et al.
(author)
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Potential benefits of managed aquifer recharge MAR on the Island of Gotland, Sweden
- 2019
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In: Water. - : MDPI AG. - 2073-4441. ; 11:10
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Journal article (peer-reviewed)abstract
- The Island of Gotland (3000 km2), east of mainland Sweden, suffers from insufficient water availability each summer. Thin soils and lack of coherent reservoirs in the sedimentary bedrock lead to limited reservoir capacity. The feasibility of Managed Aquifer Recharge (MAR) is explored by identifying suitable areas and estimating their possible contribution to an increased water availability. MARis compared to alternative water management measures, e.g., increased groundwater abstraction, in terms of costs and water availability potential. Results from GIS analyses of infiltration areas and groundwater storage, respectively proximity to surface water sources and surface water storage were classified into three categories of MAR suitability. An area of ca 7700 ha (2.5% of Gotland) was found to have good local conditions for MAR and an area of ca 22,700 ha (7.5% of Gotland) was found to have moderate local conditions for MAR. These results reveal the MAR potential on Gotland. The water supply potential of MAR in existing well fields was estimated to be about 35% of the forecasted drinking water supply and 7% of the total water demand gap in year 2045. It is similar in costs and water supply potential to increased surface water extraction. © 2019 by the authors.
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| 7. |
- Georgiou, C., et al.
(author)
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Self-stabilization overhead: A case study on coded atomic storage
- 2019
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In: Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics). - Cham : Springer International Publishing. - 1611-3349 .- 0302-9743. ; 11704 LNCS, s. 131-147
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Conference paper (peer-reviewed)abstract
- Shared memory emulation on distributed message-passing systems can be used as a fault-tolerant and highly available distributed storage solution or as a low-level synchronization primitive. Cadambe et al. proposed the Coded Atomic Storage (CAS) algorithm, which uses erasure coding to achieve data redundancy with much lower communication cost than previous algorithmic solutions. Recently, Dolev et al. introduced a version of CAS where transient faults are included in the fault model, making it self-stabilizing. But self-stabilization comes at a cost, so in this work we examine the overhead of the algorithm by implementing a system we call CASSS (CAS Self-Stabilizing). Our system builds on the self-stabilizing version of CAS, along with several other self-stabilizing building blocks. This provides us with a powerful platform to evaluate the overhead and other aspects of the real-world applicability of the algorithm. In our case-study, we evaluated the system performance by running it on the world-wide distributed platform PlanetLab. Our study shows that CASSS scales very well in terms of the number of servers, the number of concurrent clients, as well as the size of the replicated object. More importantly, it shows (a) to have only a constant overhead compared to the traditional CAS algorithm and (b) the recovery period (after the last occurrence of a transient fault) is no more than the time it takes to perform a few client (read/write) operations. Our results suggest that the self-stabilizing variation of CAS, which is CASSS, does not significantly impact efficiency while dealing with automatic recovery from transient faults.
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| 8. |
- Gärtner, Nadine, 1990, et al.
(author)
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Integrating Ecosystem Services into Risk Assessments for Drinking Water Protection
- 2022
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In: Water (Switzerland). - : MDPI AG. - 2073-4441 .- 2073-4441. ; 14:8
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Journal article (peer-reviewed)abstract
- Water protection is a widely supported goal in society, but competing interests often complicate the implementation of water protection measures. Moreover, the benefits of protection efforts are typically underestimated as risk assessments focus on the provision of drinking water and neglect the additional services provided by a clean drinking water source. We developed a list of water system services (WSS) that allows assessment of all biotic and abiotic services provided by a drinking water source. The WSS were derived from the Common International Classification of Ecosystem Services (CICES). The objectives of this paper are to (i) introduce the concept of WSS, (ii) describe a procedure on how to develop a region-specific list of WSS and present a list of WSS specifically tailored to Sweden, (iii) present how to integrate WSS into a risk assessment for drinking water, and (iv) illustrate a practical application on a Swedish case study. The results, presented as an assessment matrix, show the provided services and contrast the hazard sources with their impact on all services. The WSS assessment can be used to communicate and negotiate the extent of water protection measures with relevant stakeholders and illustrate synergies and trade-offs of protective measures beyond drinking water protection.
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| 9. |
- Hassellöv, Ida-Maja, 1974, et al.
(author)
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Miljörisker sjunkna vrak
- 2014
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Reports (other academic/artistic)abstract
- Arbetet med en nationell strategi för hantering av miljöfarliga vrak påbörjades 2007 med Statskontorets utredning Vrak och ägarlösa båtar, men ingen enskild myndighet har tilldelats övergripande ansvar för vrakfrågan. Utöver ansvarsfrågan har också förväntade höga kostnader för inspektion och sanering av vrak fördröjt det fortsatta arbetet. Ett steg närmare en nationell strategi redovisas här genom regeringsuppdraget Miljörisker sjunkna vrak. Genom samordning och ökat informationsutbyte mellan berörda myndigheter finns stor potential att minska de förväntade kostnaderna för inspektion av vrak och omgivande miljö. Om den föreslagna strategin antas, beräknas informationsläget avseende vraken att snabbt förbättras så att det år 2030 inte längre finns några potentiellt miljöfarliga vrak i svenska vatten.Havs- och vattenmyndigheten (HaV) och Naturvårdsverket har idag delat ansvar för övervakning och åtgärdande av miljögifter i marin miljö. Mot denna bakgrund hade det varit naturligt att låta HaV få ett övergripande ansvar för hantering av miljöfarliga vrak. Genom flexibelt upplägg avseende tidsramar bedöms övervakning och inspektion av potentiellt miljöfarliga vrak kunna utföras genom att HaV ger de berörda myndigheterna uppdrag; kartering och sjömätning (Sjöfartsverket), ROV och dykinspektion (Kustbevakningen och/eller Försvarsmakten), sediment- och bottenförhållanden (Statens geologiska undersökning). En förutsättning är dock väl fungerande samverkan och kommunikation mellan berörda myndigheter. Existerande plattformar för detta finns redan på såväl operativ nivå i form av Projekt ”Sjöstjärnan” - samordning och samverkan mellan myndigheter avseende information och inhämtning av djup- och bottendata; respektive högsta ledningsnivå i form av Samordningsgruppen för havs- och vattenmiljöfrågor (SamHav).Enligt Sjöfartsverkets tidigare inventering (Miljörisker från fartygsvrak, 2011) finns det utmed Sveriges kust knappt tre tusen vrak som inte kan avskrivas utan vidare informationsinhämtning. Drygt trehundra av dessa klassades som potentiellt miljöfarliga. Av dessa har 31 listats som de sannolikt mest miljöfarliga vraken. Listan över de 31 vraken har därför varit utgångspunkt för projektet Miljörisker sjunkna vrak, vars syfte var att ta fram en metod för prioritering och inspektion av potentiellt miljöfarliga vrak.Undervattensinspektion av vrak är kostsamt och kostnaden ökar kraftigt om vrakets läge är otillgängligt. Av de 31 vraken valdes därför nio relativt lättillgängliga vrak ut för noggrannare arkivstudier, samt sjömätning. Utifrån informationen från arkivstudierna och sjömätningen gjordes ett ytterligare urval om fyra vrak (Altnes, Skytteren, Thetis och Villon), vilka även inspekterades med ROV och/eller dykare. Huvudsyftet var att, inför och under arbetet med inspektionerna, utarbeta Standard Operating Procedures (SOPs) som framgent kan användas som stöd inför kommande operationer rörande potentiellt miljöfarliga vrak.Under arbetet med inspektionerna observerades inte några pågående läckage av olja från vraken. Trots denna positiva information är det viktigt att komma ihåg att endast bevis på tomma tankar kan fullt ut avskriva vraken från listan över potentiellt miljöfarliga vrak. Även om det under projektets fältarbete inte observerades läckage av olja, finns dokumenterade läckage sedan tidigare (senast 2008-04-26) för Skytteren. Noterbart är också att Kustbevakningen 2014-06-29, fick rycka ut för att omhänderta olja som börjat läcka efter vraket Immen, norr om Gotska Sandön. Immen var inte med bland fallstudieobjekten i projektet.I tillägg till undervattensinspektion placerades strömmätningsutrustning ut vid vraken Skytteren och Villon. Strömdata kan sedan användas för att modellera ett hypotetiskt spill av olja från ett vrak och ge en indikation på var läckage av olja kan tänkas påverka den marina miljön negativt. Exempel på sådana negativa effekter kan vara försämrad förmåga hos sedimentlevande organismer att omsätta näringsämnen, vilket i sin tur kan påverka hela det marina ekosystemet. Strömdata är också ett viktigt underlag för utformning av övervakningsprogram, exempelvis med passiva provtagare för att detektera läckage av miljöfarlig substans från vrak.Samtlig insamlad data kommer att användas för att validera riskbedömningsverktyget VRAKA, som möjliggör resurseffektiv prioritering av vilka vrak som bör undersökas och/eller saneras. VRAKA, SOPs för inspektion, samt tillgång till specifik kompetens för utvärdering av samtliga resultat är nyckelelement för att kunna presentera en tillförlitlig riskbedömning av potentiellt miljöfarliga vrak. Havs- och vattenmyndigheten skulle kunna vara lämplig myndighet med huvudansvar för miljöfarliga vrak, i operativ samverkan med övriga berörda myndigheter.
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| 10. |
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