Evaluación de la concentración de metales pesados en la alimentación primaria de ganado bovino en zonas de la provincia de Chimborazo afectadas por la ceniza del volcán Tungurahua y estudio de su impacto en la cadena trófica

Abstract

The main objective of this research study was to examine the concentration of heavy metals (HM) in areas of the province of Chimborazo that were affected by ash from the Tungurahua volcano and its impact of it on the food chain. Soils, plant material (stems, leaves, and fodder roots), and food, sampled in fifteen points of the province, were characterized physicochemically. The concentrations of Hg, As, Se, Pb, and Cd were determined by atomic absorption spectroscopy. The impact of HM in the food chain was evaluated with bioconcentration, translocation, and biotransfer factors. For risks in the consuming population, the target hazard ratio, hazard index, and estimated daily intake. The HM Cd, Pb, and Se were below the maximum tolerable concentrations (As <0.1 ppm; Cd < 0.05 ppm; Se <0.05 ppm) established by the EPA and CODEX ALIMENTARIUS in all cases. In soils, As exceeded the limits established by the EPA (<0.01 ppm) in nine points, while in plant material the concentrations of Hg in the roots exceeded the limit indicated by the CODEX ALIMENTARIUS (<0.001 ppm) in all the sampled points. The correlation study between the soil that was analyzed, and plant material reported non-significant coefficients in all cases.Bioaccumulation factors were calculated for lead in six zones a BCF <1 was obtained, thirteen reported a TF <1, and in nine a BTF <1 was also found. The HI, EDI, and THQ for lead showed values less than 1, therefore, it does not indicate a negative impact on the health of the consuming population despite its entry into the food chain. It is recommended to carry out the determination of heavy metals using more sensitive methods than the one used in the present investigation and also to design remediation plans.