Geaccumulation index and enrichment factor for lead, cadmium and nickel in agricultural soils of San Alfonso area in Machachi

Geoaccumulation index and enrichment factor of lead, cadmium and nickel inagricultural soil samples from San Alfonso in the Parish of Machachi, MejíaCounty, through the application of techniques for geochemical normalizationwere determined. All determinations were performed by atomic absorptionflame spectroscopy. Lead and cadmium are expressed as major contaminants.90 % of the batch had lead concentration values higher than 25 mg/kg, whereas100 % of the batch had cadmium values concentration higher than 0,5 mg/kg.The enrichment factor for lead showed values between 10,3 and 12,9, whichindicates a moderate enrichment different of the bedrock mineral. In the caseof cadmium, the values are between 484,8 and 568,1 indicating a high enrich-ment and serious pollution of anthropogenic origin. For nickel, the values areless than 10 so its enrichment comes only from the bedrock. Regarding geoac-cumulation index, for the case of lead, values between 0,7 and 1,1 classifies itas a moderate contaminant. For cadmium values from 6,4 to 6,6 indicate ex-treme contamination. The values for nickel are lower than 0, indicating that themetal is not present as a contaminant. In the case of cadmium, it was shownthat there is a serious contamination of anthropogenic origin, which may bedue to the proximity of a junkyard that runs along the study area