Ascar Loreto, Ahumada Inés, Richter Pablo
Departamento de Química Inorgánica y Analítica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Casilla 233, Santiago, Chile.
Chemosphere. 2008 Jan;70(7):1211-7. doi: 10.1016/j.chemosphere.2007.08.012. Epub 2007 Sep 21.
The effect of biosolid incorporation on arsenic distribution in Mollisol soils in central Chile was studied. Two soils were sequentially extracted for arsenic with a five-step method that accounts for the following arsenic forms: non-specifically adsorbed (F1), specifically adsorbed (F2), amorphous and poorly crystallized Fe and Al oxides (F3), well-crystallized Fe and Al oxides (F4) and residual (F5). The arsenic residual fraction was predominant in Pintué soil, whereas in Graneros soil, arsenic was mostly associated to amorphous Fe and Al oxides. Graneros soil exhibited a higher As(V) adsorbing capacity than Pintué soil, which relates to the higher clay and iron and aluminum oxides contents, confirming that these components participation is essential for the adsorption of this metalloid. Biosolid application at a rate of 100Mg ha(-1) caused an increase in arsenic bound to amorphous Fe and Al oxides and in the residual fraction, in Pintué soil. When Pintué soil was spiked with arsenic, aged for two months, and treated with biosolid (100Mg ha(-1)), the content of arsenic in the most labile fractions decreased, thus showing a favorable effect in its application to soils with few specific sites for arsenic adsorption. Arsenic speciation was carried out in the first two fractions of the sequential extraction procedure. As(V) was the main form in both fractions. Biosolid incorporation at a rate of 100Mg ha(-1) caused a significant increase in organic arsenic forms.
研究了在智利中部种植土中添加生物固体对砷分布的影响。采用五步方法对两种土壤中的砷进行连续提取，该方法考虑了以下砷形态：非特异性吸附态（F1）、特异性吸附态（F2）、无定形和结晶度差的铁铝氧化物结合态（F3）、结晶良好的铁铝氧化物结合态（F4）和残渣态（F5）。在平图埃土壤中，砷的残渣态占主导，而在格拉内罗斯土壤中，砷主要与无定形铁铝氧化物结合。格拉内罗斯土壤比平图埃土壤表现出更高的As(V)吸附能力，这与更高的粘土、铁和铝氧化物含量有关，证实了这些组分的参与对于这种类金属的吸附至关重要。在平图埃土壤中，以100Mg ha(-1)的速率施用生物固体导致与无定形铁铝氧化物结合的砷和残渣态砷增加。当向平图埃土壤中添加砷、陈化两个月并施用生物固体（100Mg ha(-1)）时，最不稳定组分中的砷含量降低，从而表明其在应用于砷吸附特定位点较少的土壤时具有良好效果。在连续提取程序的前两个组分中进行了砷形态分析。在这两个组分中，As(V)都是主要形态。以100Mg ha(-1)的速率添加生物固体导致有机砷形态显著增加。
