Re: identify which jobs make a connection to a specific Database source
If you want to see who (or what) accesses a specific database, you'll need DBQL Object Logging turned on. Then, you can look at the DBQLObjTbl in conjunction with the DBQLogTbl to show usernames, application IDs, IP Addresses, SQL, etc. that access a particular database.
Now, as for the ETL Job information, I don't know what it's going to be easy to figure out. Unless you set up something like query banding, ETL job information isn't passed to Teradata. It sounds like you're using DataStage for ETL. Depending on your version, the SET QUERY_BAND statement isn't supported so this isn't really an option. It's been a while since I've looked at Metadata Services, but the last time I used it, it only showed you data you explicitly loaded into it. So unless you can get the data out of DataStage (or any ETL tool), Metadata Services doesn't gain you much here.