Selenium content in soils from Murcia Region (SE, Spain)

The objective of this study was to determine the selenium content in soils from the Region of Murcia (SE, Spain) and to study the possible relationship between mineralogical composition, soil properties and selenium content. In addition, generic reference level (GRL) for selenium was determined according to Spanish legislation. For this study, 490 samples were selected in areas subjected to agricultural activity or abandoned agricultural soils with natural vegetation. Five different zones were established in order to study selenium variability. Four different mineralogical groups were established, based on significant relationship with the mineralogical composition, and each sample was included in one mineralogical group. The results showed that the concentration of selenium is correlated with the electrical conductivity, sulphate content and with the mineralogical composition, particularly positively with quartz and in a negative way with calcite percentage. In addition, selenium level was positively correlated with the phyllosilicate content. Established GRL for selenium varies with the mineralogical group, having a great transcendence from the legal and economic points of view.

Research Highlights
► Selenium levels in Murcia Region soils are similar to those values found in other non-contaminated world soils developed over limestones and metamorphic materials.
► Selenium content in soil samples from Murcia Region was related with the electrical conductivity, sulphate content and with the phyllosilicate content.
► Established Generic reference level for selenium varies with the mineralogical group.