Subsoil TPH contamination in two oil pipeline pumping stations and one pipeline right-of-way in north Mexico.

This investigation deals with the characterization carried out in zones around two pipeline pumping stations and one pipeline right-of-way in the north of Mexico. In particular those areas where contamination was evaluated: (a) south area of the separation ditch in the Avalos station, (b) the area between the separation ditch at the Avalos station, (c) km 194+420 of the Moctuzma station, and (d) km 286+900 in the Candelaria station. Results of this investigation showed that only four samples showed TPH values higher than the Mexican limit for 2004: AVA 1B, with 21,191 mg kg(-1); AVA 1C, with 9348 mg kg(-1); AVA 2B, with 13,970 mg kg(-1); and MOC 2A, with 4108 mg kg(-1).None of the sampled points showed the presence of PAHs at values higher than those found in the Mexican or American legislations. PAH were detected in the range of 0.0004 and 13.05 mg kg(-1).It is suggested to implement surfactant soil washing as a remediation technique for the approximately 600 m(3) that need to be treated.