OPRC Level 3 Causes, Fate and Effects of Spilled Oil

OPRC Level 3 2 Overview Sources and Causes Fate and Behaviour Effects and Issues Case Studies

OPRC Level 3 3 Oil Inputs To The Marine Environment Offshore production Land based Natural Atmosphere Transportation Non tanker accidents Scrapping ships Non tanker operations (bilges & fuel oil) Tanker accidents Marine terminals Tanker operations Dry docking Source: IMO estimates Total= 2.35 Mt

OPRC Level 3 4 Number Of Spills > 700 Tonnes

OPRC Level 3 5 Quantities Of Oil Spilt

OPRC Level 3 6 Incidence of Spills by Cause <7 Tonnes Tonnes >700 Tonnes Total OPERATIONS Loading/Discharging Bunkering Other operations ACCIDENTS Collisions Groundings Hull Failures Fire & Explosions Other/unknown TOTAL

OPRC Level 3 7 Loading / Discharging Oil

OPRC Level 3 8 Bunkering Operations

OPRC Level 3 9 Grounding

OPRC Level 3 10 Collision

OPRC Level 3 11 Spill Risk Factors Quantity of oil transported Local navigation features: –traffic density –weather and sea conditions –visibility –water depth and nature of seabed Operations in progress: –entering / leaving port –loading / unloading / bunkering oil

OPRC Level 3 12 Oil Types Crude oil Some refined products: –Gasoline (petrol) –Diesel –Bunker C –Lubricating oils

OPRC Level 3 13 Persistent and Non-persistent Oils Persistent –many crude oils –heavy products including fuel oil –lubricating oils Non persistent –kerosene –diesel oil –petrol

OPRC Level 3 14 Properties of Oil Specific gravity / o API: density Viscosity: resistance to flow Pour point: temperature below which oil does not flow Volatility: propensity to evaporate Asphaltene content: propensity to emulsify

OPRC Level 3 15 Fate and behaviour of Spilled Oil Major processes: Drifting/movement Spreading Evaporation Emulsification Dispersion Minor processes: Biodegradation Dissolution Photo-oxidation Sedimentation Shoreline interaction

OPRC Level 3 16 Fate of Oil Spilled at Sea

OPRC Level 3 17 Relative Importance of weathering Processes over Time Evaporation Dissolution Photo-oxidation Biodegradation Sedimentation Emulsification Dispersion Spreading 0 1 Hours Day WeekMonth Year Processes Over Time unstable emulsion Stable “mousse”

OPRC Level 3 18 Main Effects of Weathering Processes Increase in volume Change in properties and colour EMULSIFICATION Reduction in volume Enhances biodegradationDISPERSION Reduction in volume Changes in oil propertiesEVAPORATION

OPRC Level 3 19 Drifting at Sea marina time A time B 100% current 3% wind

OPRC Level 3 20 Effects of Spilled Oil Impacts caused by: Toxic effects Physical effects continued.

OPRC Level 3 21 Effects of Spilled Oil Sensitive environments(eg mangroves, marshes, mud flats) Birds and marine mammals Tourism and leisure activities Fishing and aquaculture Industry and water intakes

OPRC Level 3 22 Sensitive Environments

OPRC Level 3 23 Birds and marine mammals

OPRC Level 3 24 Tourism and Leisure Activities

OPRC Level 3 25 Fishing and aquaculture

OPRC Level 3 26 Industry and water intakes

OPRC Level 3 27 Policy Issues Handling the media Fishing bans Bathing bans Health risks to public and workers Perceptions of damage Environmental damage / monitoring

OPRC Level 3 28 Braer – United Kingdom, tonnes of light crude oil High level of natural dispersion Relatively little clean-up/response required Major impact on fisheries and aquaculture

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OPRC Level 3 30 Erika – France, tonnes very persistent heavy fuel oil Oil stranded over a long distance Difficult to observe from the air Highly viscous emulsion Problems: clean-up, access, disposal Impacts: fisheries, aquaculture, amenities

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OPRC Level 3 32 Prestige – Spain, 2002 Cargo of 77,000 tonnes of heavy fuel oil; unknown quantities released 800 km of Spanish beaches affected plus impact on French coasts Significant oiling of coasts and waste disposal problems Large impact on fishing Lesser impacts on aquaculture and tourism industries

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OPRC Level 3 34

OPRC Level 3 35 Key Messages Vast majority of spills are small (<7 t) Catastrophic tanker spills are rare Properties of spilt oil change over time: this affects response options Oil spills can have a major impact on: –Sensitive environments –Tourism and leisure activities –Industry, fishing and aquaculture