VRAKA—A Probabilistic Risk Assessment Method for Potentially Polluting Shipwrecks

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

Comparing emissions of polyaromatic hydrocarbons and metals from marine fuels and scrubbers

In January 2020, new global regulations were implemented to limit the maximum sulphur content in marine fuels. As an alternative to switch to compliant fuels, the regulations allow for installations of exhaust gas cleaning systems, e.g. scrubbers, that enables a continued use of less expensive heavy fuel oils (HFOs). Characterization of scrubber discharge water shows that the acidified water also becomes enriched with contaminants, and large quantities of metals and polyaromatic hydrocarbons (PAHs) are thus being discharged directly to the marine environment. When emissions of contaminants to the atmosphere and the marine environment are evaluated simultaneously, the results show that HFO, with scrubbers installed, generates higher emission factors of both metals and PAHs compared to MGO. This highlights the importance of including both the marine and the atmospheric perspective when comparing environmental loads and impact of contaminants from shipping

Use of port State control inspection data from the Paris MoU to assess pressure from shipping on the marine environment

In this report we analyse the relation between the Port State Control (PSC) system, as implemented by Paris Memorandum of Understanding (Paris MoU), and the Marine Strategy Framework Directive (MSFD), which obligates EU member States to achieve a Good Environmental Status of their marine waters. The deficiency codes in the Paris MoU PSC THETIS list were reviewed to explore how the codes relate to, i.e. directly or indirectly affect, the marine environment. We further sorted these identified deficiency codes into different, partly overlapping, categories based on their relation to MSFDdescriptors. The number of deficiencies in the different categories were thereafter used as indices to infer pressures on the marine environment from different classes of ships. The approach was applied on a PSC inspection data set of ships that operated in the Baltic Sea or Skagerrak in 2018 to investigate if the number of deficiencies in four deficiency categories differed among ship types, ships of different ages and ships from different flagstates. We also analysed how deficiencies related to five different MSFD descriptors were distributed among ship classes.General cargo, container and dry bulk ships had on average more deficiencies per ship than other ship types. The youngest ships had on average fewer deficiencies per ship than older ships and ships from black and grey listed flag states had on average more deficiencies per ship than ships from white listed flag states. Ships registered in Sweden had on average fewer deficiencies per ship than average ships from white-listed flag states. The number of all deficiencies per ship was generally correlated with the number of deficiencies related to the marine environment. Thus, on a general level, the totalnumber of registered deficiencies also reflected the relative environmental performance of different ship classes. However, on a more detailed level, when deficiencies related to specific MSFD descriptors were analysed, some deviances from this general pattern were observed.The number of ships, as well as the total travelled distance, differed greatly among the different classes of ships. The total pressure on the Baltic marine environment, will, therefore, be larger from the more common middle-aged ships than from older ships, even though older ships on average performed worse than young and middle-aged ships. Similarly, because ships from white listed flag states are much more common, the total number of deficiencies of ships registered in white listed flag states, and hence, the total pressure on the marine environment, is much higher than the total number of deficiencies of, and total pressures from, ships from black and grey listed flag states. The insight that the total pressure of a class of ships is affected not only by the average performance of the ships in that class, but also by the number of ships and the total travelled distance, does not in any way reduce the need to stop the operation of the worst performing individual ships, and by various means to improve the average performance of ships in the low performing general cargo and dry bulk ship classes. From a marine environment management perspective, it is also important to recognize that alsocontinuous smaller improvements of the performance of the more numerous middleaged ships and of ships registered in white listed flag states will increase the possibility to achieve Good Environmental Status of the marine environments in Europe.We conclude that although the Paris MoU scheme for Port State Controls is an important measure to prevent pollution from ships, there is no harmonization between the work of Paris MoU and the marine environmental management in the EU including the implementation of MSFD. At least eight of the eleven descriptors of the MSFD are influenced by shipping but at least three of them cannot be evaluated by the present scheme for PSC. It is possible, according to our view, to develop the present PSC system to also include control measures that focus on these three descriptors, that is, on theeffect on biodiversity, sea-floor integrity and on the production of underwater noise. It is also important to investigate ways to add or modify deficiency codes that would capture the chemical composition of waste streams and remnant chemicals after tank cleanings. An additional development of the PSC system could be to also investigate the behaviour of ships during the period between PSC inspections, e.g. through the use of logged AIS data. The proposed system development would likely require both new financial resources and competencies

In situ observations of turbulent ship wakes and their spatiotemporal extent

In areas of intensive ship traffic, ships pass every 10ĝ€\uafmin. Considering the amount of ship traffic and the predicted increase in global maritime trade, there is a need to consider all types of impacts shipping has on the marine environment. While the awareness about, and efforts to reduce, chemical pollution from ships is increasing, less is known about physical disturbances, and ship-induced turbulence has so far been completely neglected. To address the potential importance of ship-induced turbulence on, e.g., gas exchange, dispersion of pollutants, and biogeochemical processes, a characterisation of the temporal and spatial scales of the turbulent wake is needed. Currently, field measurements of turbulent wakes of real-size ships are lacking. This study addresses that gap by using two different methodological approaches: in situ and ex situ observations. For the in situ observations, a bottom-mounted acoustic Doppler current profiler (ADCP) was placed at 32ĝ€\uafm depth below the shipping lane outside Gothenburg harbour. Both the acoustic backscatter from the air bubbles in the wake and the dissipation rate of turbulent kinetic energy were used to quantify the turbulent wake depth, intensity, and temporal longevity for 38 ship passages of differently sized ships. The results from the ADCP measurements show median wake depths of 13ĝ€\uafm and several occasions of wakes reaching depths >ĝ€\uaf18ĝ€\uafm, which is in the same depth range as the seasonal thermocline in the Baltic Sea. The temporal longevity of the observable part of the wakes had a median of around 10ĝ€\uafmin and several passages of >ĝ€\uaf20ĝ€\uafmin. In the ex situ approach, sea surface temperature was used as a proxy for the water mass affected by the turbulent wake (thermal wake), as lowered temperature in the ship wake indicates vertical mixing in a thermally stratified water column. Satellite images of the thermal infrared sensor (TIRS) onboard Landsat-8 were used to measure thermal wake width and length, in the highly frequented and thus major shipping lane north of Bornholm, Baltic Sea. Automatic information system (AIS) records from both the investigated areas were used to identify the ships inducing the wakes. The satellite analysis showed a median thermal wake length of 13.7ĝ€\uafkm (nCombining double low line144), and the longest wake extended over 60ĝ€\uafkm, which would correspond to a temporal longevity of 1ĝ€\uafh 42ĝ€\uafmin (for a ship speed of 20ĝ€\uafkn). The median thermal wake width was 157.5ĝ€\uafm. The measurements of the spatial and temporal scales are in line with previous studies, but the maximum turbulent wake depth (30.5ĝ€\uafm) is deeper than previously reported. The results from this study, combined with the knowledge of regional high traffic densities, show that ship-induced turbulence occurs at temporal and spatial scales large enough to imply that this process should be considered when estimating environmental impacts from shipping in areas with intense ship traffic

Deep learning for deep waters: An expert-in-the-loop machine learning framework for marine sciences

Driven by the unprecedented availability of data, machine learning has become a pervasive and transformative technology across industry and science. Its importance to marine science has been codified as one goal of the UN Ocean Decade. While increasing amounts of, for example, acoustic marine data are collected for research and monitoring purposes, and machine learning methods can achieve automatic processing and analysis of acoustic data, they require large training datasets annotated or labelled by experts. Consequently, addressing the relative scarcity of labelled data is, besides increasing data analysis and processing capacities, one of the main thrust areas. One approach to address label scarcity is the expert-in-the-loop approach which allows analysis of limited and unbalanced data efficiently. Its advantages are demonstrated with our novel deep learning-based expert-in-the-loop framework for automatic detection of turbulent wake signatures in echo sounder data. Using machine learning algorithms, such as the one presented in this study, greatly increases the capacity to analyse large amounts of acoustic data. It would be a first step in realising the full potential of the increasing amount of acoustic data in marine sciences

Effects of seawater scrubbing on a microplanktonic community during a summer-bloom in the Baltic Sea

The International Maritime Organization (IMO) has gradually applied stricter regulations on the maximum sulphur content permitted in marine fuels and from January 1, 2020, the global fuel sulphur limit was reduced from 3.5% to 0.5%. An attractive option for shipowners is to install exhaust gas cleaning systems, also known as scrubbers, and continue to use high sulphur fuel oil. In the scrubber, the exhausts are led through a fine spray of water, in which sulphur oxides are easily dissolved. The process results in large volumes of acidic discharge water, but while regulations are focused on sulphur oxides removal and acidification, other pollutants e.g. polycyclic aromatic hydrocarbons, metals and nitrogen oxides can be transferred from the exhausts to the washwater and discharged to the marine environment. The aim of the current study was to investigate how different treatments of scrubber discharge water (1, 3 and 10%) affect a natural Baltic Sea summer microplanktonic community. To resolve potential contribution of acidification from the total effect of the scrubber discharge water, “pH controls” were included where the pH of natural sea water was reduced to match the scrubber treatments. Biological effects (e.g. microplankton species composition, biovolume and primary productivity) and chemical parameters (e.g. pH and alkalinity) were monitored and analysed during 14 days of exposure. Significant effects were observed in the 3% scrubber treatment, with more than 20% increase in total biovolume of microplankton compared to the control group, and an even greater effect in the 10% scrubber treatment. Group-specific impacts were recorded where diatoms, flagellates incertae sedis, chlorophytes and ciliates increased in biovolume with increasing concentrations of scrubber water while no effect was recorded for cyanobacteria. In contrast, these effects was not observed in the “pH controls”, a suggestion that other parameters/stressors in the scrubber water were responsible for the observed effects

Modelling spatial dispersion of contaminants from shipping lanes in the Baltic Sea

Major sources of pollution from shipping to marine environments are antifouling paint residues and discharges of bilge, black, grey and ballast water and scrubber discharge water. The dispersion of copper, zinc, naphthalene, pyrene, and dibromochloromethane have been studied using the Ship Traffic Emission Assessment Model, the General Estuarine Transport Model, and the Eulerian tracer transport model in the Baltic Sea in 2012. Annual loads of the contaminants ranged from 10-2 tons for pyrene to 100 s of tons for copper. The dispersion of the contaminants is determined by the surface kinetic energy and vertical stratification at the location of the discharge. The elevated concentration of the contaminants at the surface persists for about two-days and the contaminants are dispersed over the spatial scale of 10-60 km. The Danish Sounds, the southwestern Baltic Sea and the Gulf of Finland are under the heaviest pressure of shipborne contaminants in the Baltic Sea

Modelling of discharges from baltic sea shipping

This paper describes the new developments of the Ship Traffic Emission Assessment Model (STEAM) which enable the modelling of pollutant discharges to water from ships. These include nutrients from black/grey water discharges as well as from food waste. Further, the modelling of contaminants in ballast, black, grey and scrubber water, bilge discharges, and stern tube oil leaks are also described as well as releases of contaminants from antifouling paints. Each of the discharges is regulated by different sections of the IMO MARPOL convention, and emission patterns of different pollution releases vary significantly. The discharge patterns and total amounts for the year 2012 in the Baltic Sea area are reported and open-loop SOx scrubbing effluent was found to be the second-largest pollutant stream by volume. The scrubber discharges have increased significantly in recent years, and their environmental impacts need to be investigated in detail

ICES Viewpoint background document: Impact from exhaust gas cleaning systems (scrubbers) on the marine environment (Ad hoc).

Shipping is a diverse industry that connects the world. The distribution and intensity of commercial shipping is increasing and there is a growing need to assess and mitigate the impacts of vessel activities on the marine environment. New global standards on sulphur content in marine fuels have led to an increasing number of ships installing exhaust gas cleaning systems (EGCS), also known as scrubbers, to reduce their emissions of sulphur oxides to the atmosphere. Ships equipped with a scrubber can continue to use heavy fuel oil, and the process results in discharges of large volumes of acidified water that contain a mix of contaminants, such as heavy metals, polycyclic aromatic hydrocarbons (PAHs), oil residues, and nitrates. For the most common type of scrubber, open loop, this polluted water is directly discharged back to the sea, trading reductions in air pollution for increased water pollution. The scrubber discharge mixture has demonstrated toxic effects in laboratory studies, causing immediate mortality in plankton and exhibiting negative synergistic effects. The substances found in scrubber discharge water are likely to have further impacts in the marine environment through bioaccumulation, acidification and eutrophication. The impacts of scrubber discharge water can be completely avoided through the use of alternative fuels, such as distilled low sulphur fuels. Distilled fuels have the added benefit that they remove the threat of heavy fuel oil spills from shipping activities. If the use of alternative fuels is not adopted, and scrubbers continue to be considered an equivalent method to meet the sulphur emissions limits, then there is urgent need for:1) significant investment in technological advances and port reception facilities to allow zero discharge closed loop scrubber systems;2) improved protocols and standards for measuring, monitoring and reporting on scrubber discharge water acidity and pollutants;3) evidence-based regulations on scrubber water discharge limits that consider the full suite of contaminants