Copper continued soil corrosion

Copper finds many applications in the handling of seawater and/or fresh water. The corrosion resistance of copper, when in contact with fresh water or seawater, is dependent upon the surface oxide film that forms. For corrosion to continue, oxygen must diffuse through this film. High-velocity water will disturb the film, whereas carbonic acid or organic acids that are present in some fresh waters and soils will dissolve the film. Either situation leads to an appreciably high corrosion rate. If the water velocity is limited to 4r-5 ft/s, the film will not be disturbed. 

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