Abstract

GONZALEZ HERRERA, Roger; RODRIGUEZ CASTILLO, Ramiro  and  CORONADO PERAZA, Víctor. Natural attenuation in the aquifer of Yucatán. Rev. Int. Contam. Ambient [online]. 2007, vol.23, n.1, pp.5-15. ISSN 0188-4999.

Natural attenuation means dilution, dispersion, (bio)degradation, irreversible adsorption and/or radioactive decay of contaminants in soils and groundwater. It causes a reduction in contaminant toxicity and decreases human and ecological risk. Nevertheless these mechanisms are rarely used for the remediation of contaminated aquifers. Natural attenuation was characterized in situ at the municipal waste disposal site in Mérida, Yucatán, México. The closed dumpsite does not count with a bottom liner system causing migration of leachate to the local karstic aquifer. When it was closed, in April 1998, a program was implemented to identify attenuation mechanisms of contaminants infiltrated in the shallow groundwater table located five meters below ground level. This program results in a methodology helping to identify whether or not natural attenuation is effective in this karstic system. A contaminant plume was identified in the direction of groundwater flow whose extension was less than one kilometer. Based on a statistical analysis it was confirmed that a contaminant attenuation process was under way.

Keywords : groundwaters; contamination; natural attenuation; karst; Yucatán.

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