赤泥和骨炭对污染土壤As化学形态及其生物可给性的影响

EFFECTS OF RED MUD AND BONE CHAR ADDITION ON FRACTIONATION AND BIO-ACCESSIBILITY OF ARSENIC IN CONTAMINATED SOIL

通过室内土壤培养实验,研究添加赤泥和骨炭对污染土壤As化学形态及其生物可给性的影响.结果表明,培养3个月后,添加5%赤泥促进了土壤中As从结晶铁铝水化氧化物结合态向专性吸附态和残渣态的转化;添加5%骨炭促进了土壤中As从结晶铁铝水化氧化物结合态向专性吸附态和非专性吸附态的转化.培养3个月后,土壤中生物可给性As含量随着赤泥和骨炭用量的增加而显著增加.当赤泥和骨炭用量为5%时,土壤中生物可给性As含量分别比对照提高6.25倍和12.31倍.添加赤泥和骨炭增强了土壤中As的移动性,提高了As对人体的健康风险.

Effects of red mud and bone char addition on the fractionation and bio-accessibility of As in contaminated soil were studied by batch soil column incubation experiment.Seven treatments were designed：control,1%,2% and 5% red mud addition（by weight）,1%,2% and 5% bone char addition.Results showed that 5% red mud addition resulted in the transformation of As fractions from well-crystalline hydrous oxides of Fe and Al to specifically-sorbed and residual phase after 3 months incubation;5% bone char addition resulted in the transformation of As fractions from well-crystalline hydrous oxides of Fe and Al to specifically-sorbed and non-specifically sorbed after 3 month incubation.Compared with the control,contents of bio-accessible As increased remarkedly with the increasing amount of red mud and bone char addition.Contents of bio-accessible As were increased by 6.25-fold and 12.31-fold with 5% red mud and 5% bone char addition after 3 months incubation.Addition of red mud and bone char enhanced the mobility of As in soil,and raised the health risk of As to humans.