Eroding Wave-Cut Platforms 



Deposited oil is removed relatively rapidly (several weeks) from this 

 environment because of its wave-swept condition. At the Metula site, all 

 traces of oil were eliminated from wave-cut platforms by the time of our first 

 site survey 1 year after the wreck. 



Flat, Fine-Grained Sand Beaches 



Compact, fine-sand beaches inhibit oil penetration; and, as they gener- 

 ally respond slowly to wave or tidal activity, the depth of oil burial is min- 

 imal. As indicated at several oil-affected, fine-sand beaches in Spain and 

 France, indigenous amphipod populations are likely to be destroyed, although 

 recovery may occur over the following several months. Cleanup is simplified 

 by the presence of a hard substrate. 



S teeper, Medium- to Coarse-Grained Sand Beaches 



As observed at the Urquiola spill site, oil burial and penetration may 

 be great on depositional medium- to coarse-sand beaches. Cleanup tends to 

 grind oil into the beach because of the loose packing of the sediment. After 

 a major spill, oil from the beach face is eliminated by natural wave activity 

 usually within months. 



Exposed, Compacted Tidal Flats 



As observed at the Metula and Urquiola spill sites, oil does not readily 

 adhere to, or penetrate into, the compact surface of these sand or mud flats. 

 However, biological damage can be very extensive. At the Amoco Cadiz spill 

 site, millions of heart urchins and clams were killed within the shallow sub- 

 tidal zone. Perhaps in a truly biologically oriented index, this environment 

 should be rated higher. 



Mixed Sand and Gravel Beaches 



On mixed sand and gravel beaches in Spain, oil from the Urquiola rapidly 

 penetrated 30 cm into the sediment. Cleanup is difficult without damaging the 

 beach, by removing the sediment. 



Gravel Beaches 



Investigation of the Urquiola site revealed that oil penetrated most 

 deeply (60 cm) into uniformly coarse-grained sediment. Followup study of a 

 gravel beach at the Amoco Cadiz site revealed that oil persisted as fresh 

 mousse at least until 8 months after the spill. 



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