VRAKA—A Probabilistic Risk Assessment Method for Potentially Polluting Shipwrecks

Abstract

Shipwrecks around the world contain unknown volumes of hazardous substances which, if discharged, could harm the marine environment. Shipwrecks can deteriorate for a number of reasons, including corrosion and physical impact from trawling and other activities, and the probability of a leakage increases with time. Before deciding on possible mitigation measures, there are currently few comprehensive methods for assessing shipwrecks with respect to pollution risks. A holistic method for estimating environmental risks from shipwrecks should be based on well-established risk assessment methods and should take into account both the probability of discharge and the potential consequences. The purpose of this study was therefore to present a holistic risk assessment method for potentially polluting shipwrecks. The focus is set to developing a method for estimating the environmental consequences of potential discharges of hazardous substances from shipwrecks and to combine this with earlier research on a tool for estimating the probability of discharge of hazardous substances. Risk evaluation should also be included in a full risk assessment and is the subject of further research. The consequence assessment was developed for application in three tiers. In Tier 1, the probability of discharge and possible amount of discharge are compared to other shipwrecks. In Tier 2, a risk matrix, including a classification of potential consequences, is suggested as a basis for assessment and comparison. The most detailed level, Tier 3, is based on advanced tools for oil spill trajectory modeling and sensitivity mapping of the Swedish coast. To illustrate the method an example application on two wrecks is presented. Wreck number 1 present a lower probability of discharge and a lower consequence in a Tier 1 and Tier 3 assessment. For the Tier 2 consequence assessment, the two example wrecks present equal consequence. The tool for estimating the probability of discharge of hazardous substances from shipwrecks, and the approach for consequence estimation, offers a comprehensive method for assessing the risks presented by potentially polluting shipwrecks. The method is known as VRAKA (short for shipwreck risk assessment in Swedish) and provides decision support, facilitating prioritization of risk mitigation measures enabling efficient use of available resources.

Decolonising Environmental Risk Assessments of Potentially Polluting Wrecks: a Case Study of the Wreck of the USS Mississinewa in Ulithi Lagoon, Federated States of Micronesia

“…Mangroves cannot be decontaminated "because this is persistent oil, and there's been lots of studies that have shown that … there is de nitely long-term consequences to ... this pollution" (SPREP-3). The Swedish 'VRAKA' wreck risk assessment methodology offers an alternative by considering the speci c vulnerability of shorelines that could become oiled, based on how easily pollution can be remediated on different shoreline types (Amir-Heidari et al, 2019, Landquist et al, 2016). This is an important aspect of shoreline pollution persistence which affects the people, plants and animals living with pollution, but it could go further to consider human vulnerabilities speci cally.…”

“…Removing oil from a wreck costs millions of dollars (NAVSEA, 2004), making it impractical to empty them all, so they must be prioritised according to risk. Several wreck risk assessment methodologies have been devised to assess potentially polluting wrecks either globally (Michel et al, 2005;Goodsir et al, 2019) or regionally, in American (NOAA, 2013), Swedish (Landquist et al, 2016) and Greek (Ventikos et al, 2013) waters, and in the Paci c (Carter et al, 2021). All assessments use archival research to build up a picture of the wreck's condition and how much oil it is likely to contain, some use oil spill modelling to predict where spilled oil might end up, and most include an assessment of what ecological and socioeconomic resources could be impacted.…”

“…However, the frequency of such storms is not a feature of the E-DBA, despite it being considered in other wreck risk assessments (e.g Landquist et al, 2016),. nor are other natural hazards that can impact wrecks, such as tectonic activity(Dillenia et al, 2016).…”

Prediction of corrosion failure probability of buried oil and gas pipeline based on an RBF neural network

“…There are five natural language variables: little, fairly little, medium, fairly big, and big. Since the input variable must be a specific value between (0, 1) when conducting RBF neural network prediction training, this study will try to convert the language variable into a numerical variable (Landquist et al, 2016;Guo et al, 2019;Zhang et al, 2020), as shown in Table 2. Through the corresponding transformation between language variables and numerical variables, it can be determined that the input layer neuron is a 77-dimension numerical vector, and the output layer neuron is a 1-dimension numerical vector.…”

Coastal Risk Modelling for Oil Spill in The Mediterranean Sea

“…These approaches attracted growing interest both from international organizations that have suggested the use of specific risk analysis and management tools [8,9], and from researchers who focused on fundamental issues relevant to risk assessment. From the academic viewpoint, the main topics referred to terminology, concepts and perspectives of risk analysis and management in the maritime context [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25].…”