Assessment of heavy metals space-temporal evolution in protected areas from Romania. Case studies.

Good knowledge of the concentrations of chemical elements in soil in some geographical regions is fundamental to understanding the pre-existing natural background, on top of which the anthropogenic input is added, especially through pollution. There are many areas left without a geochemical assessment. In these cases knowing the areas where the contribution of the anthropic factor is non-existent or minimal is particularly important from the point of view mentioned previously. This article aims to highlight the spatial and temporal variation of 5 heavy metals identified in soil and water (surface water and underground water) within 5 protected geographical areas in Romania, chosen as case studies. In these areas, the manifestation of natural factors, namely geomorphological, lithological, edaphic, climatic, and, last but not least, the anthropogenic factor that cannot be neglected, gives the possibility of an objective, quantifiable evaluation of the areas under study. The comparisons made highlighted the zonal variability underlying the influencing factors, as well as the way in which the normal values are or are not exceeded.