A powerful tool for assessing distribution and fate of potentially toxic metals (PTMs) in soils: integration of laser ablation spectrometry (LA-ICP-MS) on thin sections with soil micromorphology and geochemistry

摘要: The dynamic behavior and inherent spatial heterogeneity, at different hierarchic levels, of the soil system often make distribution potentially toxic metals (PTMs) quite complex difficult to assess correctly. This work demonstrates that application laser ablation spectrometry (LA-ICP-MS) thin sections constitutes an ancillary powerful tool well-established analytical methods for tracing fate potential contaminants microsite level. It allowed discriminate contribution PTMs in distinct sub-components, such as parent rock fragments, neoformed, clay-enriched or humified matrix, specific pedogenetic features illuvial origin (unstained iron-stained clay coatings) even very low contents. were analyzed three profiles located Muravera area (Sardinia, Italy), where several, now abandoned mines exploited. Recurrent trends increase many from pedogenic matrix coatings, traced by LA-ICP-MS compositional data, revealed a control on metal fractionation distribution, based adsorption properties minerals, iron oxyhydroxides organic matter, downprofile illuviation processes. main patterns coupled with SEM-EDS analyses suggest heavy metal-bearing mineral grains sourced mine plants, addition natural sedimentary input. interplay between soil-forming processes geomorphic dynamics significantly contributed detected horizons features.