Content and maximum capacity of arsenic adsorption in Brazilian oxisols

In view of the toxicity of As for man and animals and the possibility of existence of a great number of contaminated areas it is imperative to know the total As content in soils considered uncontaminated and about As sorption processes in soils of variable charge. The objective of this work was to determine the total content and maximum capacity of As adsorption (CMADS(As)) in Oxisols. The total content was determined by the USEPA 3051A method. The cmADS(As) was determined by the Langmuir Isotherms using six solution concentrations (0, 0.09, 0.19, 0.38, 0.76, 1.15 mmol L-1) (1:100 soil: solution ratio), pH values 5.5 and ionic strength 15 mmol L-1. In the 17 Oxisols the average total As content was 5.92 mg kg(-1) and mean cmADSA, was 2.013 mg kg(-1). Clay, and Fe and Al oxides content influenced cmADS(s) positively.