ABSTRACT
There is much debate about what would be natural in terms of concentration of an element in soils or sediments (Reimann et al. 2009). Related answers are crucial when health hazards for humans and environment are under scrutiny. Knowledge of the natural As presence is needed to assess environmental quality and to develop actions capable of curbing soil and sediment pollution (c 17). An attempt to understand the As biogeochemistry in subtropical conditions led to a series of studies of the Iron Quadrangle that revealed positive As anomalies in different environmental compartments (Borba et al. 2000, 2003; Eleutério 1997; Haßler 2002; Matschullat et al. 2000; Rawlins et al. 1997). The dimension and number of As anomalies are a serious concern in terms of environmental impact and particularly in respect to their effect on public health. A preliminary human biomonitoring study in regions of the Iron Quadrangle revealed that As assimilation by the human body occurred (Matschullat et al. 2000; c 14). Based on these results, this chapter presents a more detailed study of surface soil material and evaluates the hypothesis that airborne dust could be decisive in As transfer to the human body (c 10). With the analysis of sediment samples, the study seeks to reply to additional questions on As dispersion in the study area. Bearing in mind the development of remedial actions for contaminated soils and sediments, this chapter also contributes to As geochemistry and As mobility in the environment (c 1).
