Uptake of potentially toxic elements by edible plants in experimental mining Technosols: preliminary assessment.

A study was carried out to evaluate the absorption of potentially toxic elements from mining Technosols by three types of vegetable plants (broccoli (Brassica oleracea var. italica), lettuce (Lactuca sativa) and onion (Allium cepa)), the different parts of which are intended for human and farm animal consumption (leaves, roots, edible parts). The preliminary results obtained highlight the importance of the design of the mining Technosols used for agricultural purposes, obtained from soils and sediments of mining origin and amended with residues of high calcium carbonate concentrations (limestone filler and construction and demolition wastes). The experiment was carried out in a greenhouse, and the total metal(loid)s concentration (As, Pb, Cd, Cu, Fe, Mn and Zn) of the soil, rhizosphere, aqueous leachates and plant samples was monitored, the translocation and bioconcentration factors (TF and BCF, respectively) being calculated. The characterization of the soils included a mobilization study in media simulating different environmental conditions that can affect these soils and predicting the differences in behavior of each Technosol. The results obtained showed that the levels of potentially toxic elements present in the cultivated species are within the range of values mentioned in the literature when they were cultivated in soils with calcareous amendments. However, when the plants were grown in contaminated soils, the potentially toxic elements levels varied greatly according to the species, being higher in onions than in lettuce. Experiments with the use of lime filler or construction and demolition wastes for soil remediation result in crops that, in principle, do not present health risks and are similar in development to those grown on non-contaminated soil.

Assessment of risk from lead intake in mining areas: proposal of indicators.

This study discusses an estimate of the risk associated with the intake of soil contaminated by lead, based on the nature of the source, through a detailed study of the parameters that can influence the bioaccessibility of the element from soil intake. Statistical variables that are related to the solubility and bioavailability of lead are used for this purpose. This includes considering the values of pH, electrical conductivity, particle size, mineralogical composition and the bioaccessibility/bioasimilability of lead. Obtaining an algorithm, represented by different probability distributions of the parameters considered, needs a thorough knowledge of the source materials, which may allow estimating/evaluating the intake health risk provided by the concentration of the metal present. The selected materials are from sites affected by mining activities in the Region of Murcia (SE of Spain) and soils in nearby areas, using a total of 186 samples. Soil samples, once screened and homogenized, were parameterized by determining pH, electrical conductivity, granulometry, both total and water-extractable Pb content. Oral bioaccessibility tests were also performed, and a detailed mineralogical analysis by X-ray diffraction was carried out.