14 
Oil Spill Identification - Round Robin 20045 
Fig 1 Bilge samples used to prepare the 
source samples. 
Two bilge samples (Fig 1) from a ship with three engines and a bilge 
tank for each engine were used. The amount of gas oil was small, but 
different for the samples. The biomarker patterns were quite similar. 
To increase the amount of gas oil the two bilge samples were mixed 
with the bilge samples of two different ships from another case, 
containing mainly gas oil(Fig 2). These bilge samples are different in the 
amount of lubricating oil and also show a different alkane pattern. 
Fig 2 Bilge samples used to prepare the 
source samples.