Suitability of a municipal solid waste as organic amendment for agricultural and metal(loid)- contaminated soils: effects on soil properties, plant growth and metal(loid) allocation in Zea mays L.

Purpose The use of municipal solid wastes (MSWs) as a lowcost source of organic matter for soils should be considered after discarding the environmental risks related to their metal(loid) load. The goal of this work was to assess the employment of a MSW as an organic amendment in two types of soil (an agricultural soil, A, and ametal(loid)-enrichedmine tailings soil, T) attending to changes in soil properties and in plant growth, nutrition and metal(loid) translocation from roots to aerial parts of Zea mays L. (stalk, leaves, tassel, husk, cob and kernel). Materials and methods After a comprehensive characterisation of each soil treatment (A, A + MSW, T, T + MSW), a potdesigned experiment was carried out. Soil solution was monthly monitored throughout the experiment, and metal(loid) concentrations were measured. Results and discussion The MSW improved some fertilityrelated parameters in both soils, A and T:increased total and dissolved organic carbon, total nitrogen and soil microbiology. However, an increase in 0.01M CaCl2-extractable metal(loid) concentration was also observed. No differences in dry biomass were found between amended and not amended treatments. A fractionation of metal(loid) concentrations among plant organs occurred. For instance, the highest Cu and Pb concentrations were found in roots, while for Zn occurred in the stalk and the cob. The amended treatments favoured the accumulation of Mn in all plant organs. Kernels showed in general the lowest metal(loid) concentrations. Conclusions The addition of municipal solid wastes as organic amendment could be a suitable tool to increase soil fertility. However, due to the high metal(loid) content of this particular MSW, its use on agricultural soils would not be appropriate. By other hand, along with the improvement of soil fertility, the MSW was useful to promote plant development in the mine tailings soil which should be then considered as a potential tool to promote plant establishment in those metal(loid)-impacted soils.