Estimation of soil and tailing dump toxicity: development and validation of a protocol based on bioindicators and ICP-OES

A protocol for estimation of soil toxicity based on germination test, open acid sample digestion and ICP-OES determination of heavy metals and metalloids was proposed. Triticum aestivum was used as a bioindicator and germinated on contaminated soils. After estimation of the state of the plantlets, the accumulated heavy metals and metalloids content were determined. The sample digestion procedure and ICP-OES measurement were validated by analysing plant certified reference material. Additionally, standard addition before sample pretreatment was applied for estimation of method recovery at the levels of heavy metals found in plants from contaminated region. The recovery obtained was between 97 and 105 %. The precisions of the complete protocol (RSD), which included germination tests, sample digestion and ICP-OES measurements, ranged between 4.7% for Mn and 11 % for As. The expanded uncertainty was estimated. The proposed protocol was applied for estimation of soil toxicity and heavy metals bioavailability of tailing dump material and surrounding soils from an abandoned barite mine in Tarniţa, Suceava, Romania. The coltsfoot used for remediation of the soil in the studied region was analysed. Cu, Ni, Zn, Mn, Pb, Fe and Al were found in the sample harvested nearby the tailing dump.