Abstract
Aliphatic hydrocarbons and hopanoid hydrocarbons were analyzed in a short (16 cm) sediment core sample from Lake Haruna, and their short-term variations were investigated.
The carbon preference index of n-C25-C33 alkanes in the core decreases from 6.0-7.7 at depths of 7-16 cm to 2.2 in the surface (0-1 cm) sediment. UCM (unresolved complex mixture: hump on a gas chromatogram) increases from the bottom sections to surface sediment, maximizing at depths of 3-4 cm. The vertical profile of UCM coincides well with that of 17α(H), 21β(H) hopanes. These vertical profiles indicate that oil pollution in Lake Haruna started in the 1940's (6-7 cm in depth) reaching its maximum between 1969-1976 (3-4 cm in depth). C31 17α(H), 21β(H) hopane proved to be the best indicator of oil pollution in sediment.
