Assessment and sources of nonaromatic hydrocarbons in surface sediments of three harbors in Santa Catarina State, Brazil.

Nonaromatic hydrocarbons and geochemical parameters from 17 sediment-water interface samples were used to assess sources of organic matter in three harbors, located in Santa Catarina State, southern Brazil. The evaluation was based on the molar C/N/P ratios, abundance of resolved nonaromatic hydrocarbons (3.0-25.9 μg g(-1)), unresolved complex mixture, and two indexes: the carbon preference index (CPI) and the low molecular weight to high molecular weight ratio. The results indicate that the organic matter is predominantly of terrestrial origin (C/N>10 and CPI>2). Variations in the total organic carbon from 0.43 to 2.98 mmol g(-1) and total phosphorus from 82.4 to 464.3 μg g(-1) showed no clear correlation with the silt and clay fractions of the sediments possibly due to anthropogenic input. In contrast to the low level of contamination based on the acyclic hydrocarbon distribution, the results obtained from a series of geologically stable hopanes and steranes reveal the presence of less degradable petroleum derivatives.