Concentrations of oils and grease (AG) and total hydrocarbons (HT) were assessed. Granulometric and
geochemical analyzes were performed on surface and subsurface layers. Seven cores were sampled in May 2010 using plastic
PVC tubes (70 x 3.5 cm) that were frozen (-4 ° C) until processing. The layers were obtained, depending on the size of the
nucleus (14 and 38 cm). AG and HT concentrations were determined using the technique of infrared. AG and HT were observed
in not-contaminant level as established by UNESCO; they showed correlations with each other (r = 0.42; p = 0.000) and mud
(r = 0.49; p = 0.05) and its vertical distribution was inconstant. The total organic matter content (MOT) and calcium
carbonate (CaCO3) were observed significantly higher and correlated with each other (r = 0.68; p = 0.000) in Caribbean islet.
Vertical distribution to MOT was similar though to CaCO3 was diverse; which may be explained by the enrichment of water,
either by upwelling; plumes tributaries of the Orinoco and Amazon rivers, the effects of internal waves and the contributions
of coastal lagoons. Hydro-geochemical conditions suitable to accumulate oils, grease and total hydrocarbons were observed in
the southern part of the Chacopata lagoon (core 3). Identified sites of ancient deposition of material biogenic calcareous in
the middle of the Chacopata lagoon area and at the mouth of the Bocaripo lagoon. Sediments were evaluated as sandy,
permeable and with natural levels of oil, grease and total hydrocarbons; they may be considered reference values.