1 discharges or accidental discharges, may cause serious harm to various 



2 marine and coastal environments. 



3 This first slide summarizes the types of discharges and activities 



4 that could result in adverse effects to the marine environment. 



5 The mere physical structure of the platform, especially if it is 



6 sitting on the bottom, as would be a production platform, can cause 



7 local reef effects, causing a localized erosion, or attracting a 



8 different fauna and flora and, therefore, changing the local 



9 environment. 



10 There are a variety of so-called reef effects, either physical or 



11 biological that can occur and have been documented in several cases. Of 



12 course, in the Arctic you have artificial islands which obviously are a 



13 physical disruption of the local environment. 



14 During drilling there are drill cuttings produced continuously 



15 during the drilling operation, and then drilling fluids used for the 



16 drilling operations, and generally about a 1,000 metric tons of cuttings 



17 are produced per well during exploration, less for production wells. 



18 Nearly about the same amount of drilling fluids. During drilling 



19 operations these materials are discharged in bulk quantities several 



20 times during the drilling operation, so there is a net discharge over 



21 the period of time when the drilling is going on. 



22 In addition, there are a variety of other discharges that are 



23 permitted by MPDS permits, including cooling water, deck drainage, 



24 ballast water, domestic sewage, and so forth. All of these effluents 



25 usually are treated on an on-board treatment system before they are 



26 discharged. 



27 Actually, the domestic sewage is treated better than most on-shore 



28 domestic sewage before discharge to the ocean. Of course, there are 



29 sources of metals and sacrificial anodes. Any time you put a metal 



30 structure below water you have to have these anodes to prevent corrosion 



31 of the structure, and these contain high levels of a variety of metals, 



32 but the total amounts here are very small. 



33 During the actual production phase, you have produced water, which 



34 is water generated during the production of the oil. It is usually 



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