【摘要】 通过野外调查与室内分析,对喀斯特林地土壤重金属全量及形态构成进行了调查,对土壤重金属污染及其生物有效性进行了评价,并探讨分析了土壤重金属与土壤pH值的相关性。结果表明:中性土壤As,Cd,Cu,Ni,Pb,Zn及Cr全量均大于酸性土壤的全量;As以酸溶态为主,Cd,Cu,Ni,Pb,Zn及Cr以残渣态为主,残渣态土壤重金属比例为中性高于酸性土壤;酸性和中性土壤重金属Pb全量、中性土壤的As和Cu全量均高于贵州土壤背景值;中性和酸性土壤重金属As,Cd和Ni全量及酸性土壤重金属Cu全量超过土壤环境质量二级标准值;酸性土壤为轻度污染,中性土壤为中度污染;重金属生物有效性表现为As>Cd>Cr>Ni>Pb>Zn>Cu,酸性土壤As生物有效性指数最高,与中性土壤相比,酸性土壤重金属生物有效性高;Cu全量、可氧化态Pb、残渣态Cu与pH值呈极显著正相关,酸溶态Zn与pH值呈极显著负相关,酸溶态Cr与pH值呈显著负相关,残渣态As与pH值呈显著正相关。喀斯特林地土壤主要受到As,Cd,Cu,Ni这4种重金属的影响,除As外,其余3种元素属于"高背境,低活性"状态。更多还原

【Abstract】 The field survey and indoor analysis were carried out to investigate the characteristics of total contents and the speciation of heavy metals in forest soil of Karst, to evaluate the heavy metal contamination and the bioavailability of heavy metals in soil, and to discuss and analyze the correlation between heavy metal and soil pH value. The results showed that the total contents of As, Cd, Cu, Ni, Pb, Zn and Cr in neutral soil were higher than those in acid soil, As mainly occurred in acid soluble fraction, Cd, Cu, Ni, Pb, Zn and Cr mainly occurred in residual fraction, and the proportion of residual fraction of heavy metal in neutral soil was higher than that in acid soil; the total contents of Pb in acid and neutral soils were higher than the soil background value in Guizhou Province, and the total contents of As and Cu in neutral soil were higher than the soil background values in Guizhou Province; the total contents of As, Cd and Ni in neutral and acid soil were higher than the secondary standard values of soil environmental quality, the total content of Cu in acid soil was higher than the secondary standard values of soil environmental quality. The comprehensive pollution index showed that the acid soil was slightly polluted, the neutral soil was moderately polluted. The bioavailability of heavy metals decreased in the order: As>Cd>Cr>Ni>Pb>Zn>Cu, the bioavailability of As in acid soil was the highest, and the bioavailability of heavy metals in acid soil was higher than that in neutral soil. The total content of Cu, the oxidizable fraction of Pb, the residual fraction of Cu were extremely significantly positively correlated with soil pH value, the acid soluble fraction of Zn was extremely significantly negatively correlated with soil pH value, the acid soluble fraction of Cr was significantly negatively correlated with soil pH value, and the residual fraction of As was significantly positively correlated with soil pH value. The forest soil in karst was mainly affected by As, Cd, Cu and Ni. Except As, the other three soil heavy metals belong to the state of high environmental background and low activity.更多还原