Multitracer studies on the effects of model acid rain on the adsorption oftrace elements on soils

Using a multitracer technique, the effects of acid rain pH on the adsorptio n of 15 trace elements on soil were studied. Kaolin, forest soil (original and with partially removed oxides), black soil (original and without organi c matter) and Kureha soil (original, with partially removed oxides, and wit hout organic matter) were employed as the adsorbents. Instead of H2SO4 solu tion, HCl solution was selected as the model acid rain based on the results of adsorption experiments on kaolin. in general, the percentage adsorption of cationic elements on three original soils and kaolin increased with inc reasing pH. The adsorption of oxyanionic elements, As and Se, on three soil s was high over the entire pH range studied, while that on kaolin was low a nd decreased with an increase in pH. The differences in the physical and ch emical properties of soils were reflected on the adsorption. The organic ma tter in soil had positive effects on the extent of adsorption of most eleme nts studied, while the oxides apparently showed positive effects only for F e and Se adsorption. The results indicate that acid rain decreases the rete ntion of cations in soil and that it increases or does not change the adsor ption of anions.