Step 1: The clue is the word "saturnine," historically tied to the metal lead through its old alchemical symbol Saturn.
Step 2: Chronic lead poisoning damages the kidneys and disturbs purine handling, so urate accumulates and deposits in joints, producing gout.
Step 3: A well-known route of exposure is moonshine or illicitly distilled liquor contaminated with lead, which classically triggers this form of gout.
Step 4: The other metals listed produce distinct toxic syndromes and are not associated with this gouty arthritis. Therefore lead is the answer.
\[\boxed{\text{Lead}}\]