Which MARPOL Annex regulates oil pollution from ships, and what is the primary discharge limit for oil content in bilge water through an approved oily-water separator?

• A. MARPOL Annex I; 15 mg/L
• B. MARPOL Annex II; 15 mg/L
• C. MARPOL Annex V; 15 mg/L
• D. MARPOL Annex VI; 15 mg/L

Answer: (A)

The main idea tested is which MARPOL part covers oil pollution from ships and what the standard is for treated bilge water. Oil pollution from ships is regulated under MARPOL Annex I, which specifically deals with oil and oily mixtures, including bilge water. When bilge water is treated through an approved oily-water separator, the oil content allowed in the discharged water is limited to 15 mg per liter, which is the same as 15 parts per million. This reflects a balance between operational practicality and environmental protection, enabling routine bilge management while limiting ocean oil pollution.

To place this in context, the other MARPOL annexes address different pollution streams: one covers cargo residues from bulk liquids, another handles garbage from ships, and another regulates air emissions from ships. Thus, the combination of Annex I and the 15 mg/L limit is the correct pairing for this question.