any hazardous and noxious substances which are carried by sea as cargo to a port or terminal in the territory of a State Party and discharged in that State. Cargo in transit which is transferred directly, or through a port or terminal, from one ship to another, either wholly or in part, in the course of carriage from the port or terminal of original loading to the port or terminal of final destination shall be considered as contributing cargo only in respect of receipt at the final destination.