ARBUSCULAR MYCORRHIZAE FUNGI IN AGRICULTURAL SOILS CONTAMINATED WITH LEAD

BLANCO, A.; SALAZAR, M.J.; BECERRA, A.; PIGNATA, M.L.; RODRIGUEZ, J.H.

Congreso; XI CONGRESO ARGENTINO DE MICROBIOLOGÍA GENERAL - SAMIGE; 2015

Regarding to high toxicity of heavy metals, polluted agricultural soils affects not only crop growth and the quality of agricultural products but also poses serious threats to human health through contamination of the food chain. Among industrial practices that contribute to heavy metals pollution in soils we can mention the lead smelters and secondary lead smelters (recycling of Pbfrom Pb-containing products). On the other hand, soil microorganisms play an important role in the mobilization and immobilization of metals, changing itsavailability to plants. In this context, the arbuscular mycorrhizal fungi (AMF) belonging to the phylum Glomeromycota, have been described in sites with heavy metals, indicating that exist a fungal inoculum adapted to these contaminated environments. AMF play a significant role in phytostabilization of toxic elements in contaminated soils by kidnapping and, in this way, helping mycorrhizal plants to survive. In the town of Bouwer, Córdoba, it worked years ago a recycling plant of lead batteries which was closed for failing to complywith emission standards of pollutants, leaving high levels of lead in soil. This area is characterized by intensive agriculture, mainly soybean (Glycine max) and other crops associated like Sorghum bicolor. The purpose of this study were: I) to evaluate the Pb content in top soils and crops (soybean and sorghum) growing in the vicinity of a former smelter in Bouwer, Córdoba; II) to determine the AMF in soybean and sorghum crops that grow in Pb contaminated soils.The concentrations of Pb in soybeans and sorghum and in top soils (bioavailable, mobilized and residual fraction) wereinvestigated. Furthermore, AMF morphospecies were identificated. The results show that the concentrations of Pb in crops at allsites (controls and close to the smelter) were above the maximum permitted levels. Regarding to Pb in soil a pollution gradientin relation to the smelter distance was observed, which values above 1000 ppm near to the source. On the other hand, the studyof AMF community showed a geometric distribution based on their rank-abundance diagram, being Glomus brohultii thedominant species. This distribution is typical of disturbed environments, being the species of Glomeromycota mentioned inassociation with heavy metals. However, no relationships were found between arbuscular morphospecies and Pb in soils.Taking into account these findings, future studies need to be performed in order to evaluate its relationship with thebioavailability of toxic metals in agricultural soils. The purpose not only is to assess the current state of crops in terms of foodsecurity but also evaluating possible soil remediation techniques.