Three Mexican crudes from El Batab (light), Paredón (medium) and El Carrizo (heavy) perforation wells were characterized with two different purposes: a) as an initial characterization of the complex mixture to be treated by physical-chemical or biological process, e.g., soil washing, biopiles, soil vapor venting, and b) with environmental forensic goals.

Gas chromatography using flame ionization (FID) and sulfur chemiluminiscence detectors (SCD) were used to visualize hydrocarbon patterns. Total petroleum hydrocarbons, diesel and gasoline fractions were estimated using the techniques suggested by EPA. In the case of the gasoline fraction, the analysis of the contribution of <C₅, >C₅>C₁₀, >C₁₀<C₁₅, and >C₁₅ (volatiles) as well as >C₁₅<C₂₀, >C₂₀<C₂₅, and >C₁₀<C₁₅ chains was performed. Besides, benzene, toluene, ethyl-benzene and xylenes measurements were carried out. The 16 PAHs suggested as priority by USEPA were measured too. An extensive quantification of metals was carried out and total sulfur was estimated for all crudes.