The weathering of rocks and consequently of the minerals that make them up leads to the formation of soils, containing these primary and secondary minerals that are organized in horizons on top of the parent rock. When these alteration products are transported (erosion) and accumulate in continental, transitional or marine sedimentation environments, they form sediment deposits in aquatic or sub-aerial environments (e.g. fluvial, lacustrine, estuarine, lagoonal, dune). Soils and sediments, although made up of minerals, have different evolutionary processes and consequently have specific geochemical signatures of the processes and conditions inherent in their formation. On the other hand, different Dimensional and Textural Classifications have been established for soils and sediments, which can add some complexity when it comes to defining their study and making comparisons.
In geochemical studies of SOILS and SEDIMENTS, it is essential to define various criteria so that the concentrations obtained can be correctly compared. The sampling methods, the type of material to be analyzed (total sample, coarse fraction, fine fraction), the analytical equipment and even the methodology for preparing the samples for analysis must be taken into account. If these conditions are not the same, it is not appropriate to make comparisons.
In pollution assessment studies, it is essential to know the Natural Geochemical Background Value, and in determining this, the conditions must be established (type of sample, analytical method, sample preparation method) that allow for accurate comparisons and verify the enrichment factor attributed to anthropogenic activity.