Two-stroke outboard marine engines typically produce
200–300 g of uncombusted polycyclic aromatic
hydrocarbons (PAHs) and other hydrocarbons per litre
of fuel (Tja¨ rnlund et al., 1996). Hydrocarbon emissions
from outboard engines may represent 30% of the total
emissions from off-road vehicles (EPA, 1996), in total
around 1.6109 l of unburned gasoline and other
hydrocarbons into US waters per year. A disadvantage
of widely used mineral-derived lubricants (MDL) is their