ENVIRONMENTAL ASSESSMENT OF DREDGING ACTIVITIES IN MEXICAN OIL TERMINALS

摘要

Between 1997-1998 an environmental diagnosis study was held at five Maritime Terminals in Mexico west & east coast, a total of 12 stations were evaluated in each site, taking into account physical and chemical water conditions as well as pollutant agents of the sediments (aromatic hydrocarbons, extractable organic material, heavy metals, total and hexavalent Cr, toxicity, granulometry) and a CRETIB (Corrosivity, Reactivity, Toxicity, Ignitability and Biological) analysis and a biological communities evaluation. The integral analysis obtained as a results of these studies allows to conclude that the evaluated environments, do not present severe damage, although they suffer some temporary changes in sediments, since the purification of the area is caused by the extraction of pollutants and of garbage without altering preserving properties, promoting the restoration of the ecosystem and the regeneration of its biota. In the same way, in the five studied areas, the results of the CRETIB analysis report that there is no dangerous material, according to the Normativity NOM-052-ECOL-1993 evaluated sediment metals in environments influenced by dredging activities presented concentrations were below the permissible maximum limits reported in this norm for dangerous residues. The biological communities presented typical characteristics of the seasonal fluctuations non due totality to dredging.