Estudio de bioacumulación de metales pesados por actividades agrícolas del cantón Pastaza en la estación experimental Pastaza - ESPOCH

Abstract

The aim of the research was to study the heavy metals bioaccumulation process due to agricultural activities in the Pastaza county, through the variability and effects of heavy metals bioaccumulation in the treatments to be studied and the risk evaluation for the ecosystem, by which the concentrations of mercury and cadmium in soil and biomass samples of the Allium fistulosum species were determined by means of the flame atomic absorption spectrophotometry method. A simple random probability sampling was used in three types of treatment: no treatment, chemical fertilizer and poultry manure. The parameters for the analysis were pH, electrical conductivity, real density, bulk density, texture and organic matter; in addition, macro and micronutrient levels were also determined. Regarding biomass, heavy metals, morphological properties as well as the accumulation and transport of heavy metals were evaluated by means of bioaccumulation (BCF) and translocation (TF) factors. The results were registered into SPSS 22 software, performing an ANOVA analysis of variance and a TUKEY-B test. It was possible to evaluate the mercury, while cadmium was detected at slight levels. Mercury is under the permissible limits established by the legislation for the use of agricultural soils, but there is an increase in the metal concentration after harvesting, this exceeds the permissible limit. The use of the BCF factor determined that the onion is MP-excluding, while the TF factor confirmed the transport of mercury in the plant by the leaf. It is concluded that the soil does not reflect an important contamination problem caused by heavy metals which represents environmental risk. It is recommended to use improved organic amendment in order to obtain better accumulation results as neutral as possible for the soil, as well as the use of more sensitive equipment when determining heavy metals.