select user from sys.dual running 2 million times

  Hi, We are having a problem where there is contention for the sys.dual table. On running the statspack reports we have found that the select user from sys.dual is running 2 million times an hour. We have tracked this down to the USER function within the SYS.STANDARD package, but we don't know why this is being called so many times. We are using ODP.NET 11.2 for client connections from the application server. Thanks for any help. Rgds. Sheryl