白洋淀沼泽化区域土壤重金属含量的剖面分布特征——以烧车淀为例

Profile Distribution of Soil Heavy Metals in the Paludification Region of Baiyangdian Lake—A Case Study of Shaochedian Lake

以烧车淀土壤为研究对象,研究白洋淀沼泽化区域7种重金属在土壤剖面(深度0～70cm)中的含量分布特征。研究结果表明,在烧车淀3块样地剖面中,各层土壤的As和Cd含量都超过了国家土壤质量一级标准;烧车淀入口剖面各层土壤中的Cr、Ni、Cu、Pb和Zn含量总体上低于国家土壤质量一级标准;而烧车淀台地和淀区剖面大部分土层的重金属含量,特别是Cu、Zn和Ni的含量都超过了国家土壤质量一级标准。在烧车淀入口土壤中,沿剖面重金属含量基本上呈由表层向下逐渐减少的变化规律,而台地和淀区土壤重金属则在中下部土层发生显著累积。烧车淀土壤中,As和Cd分别来源于不同的源;Cr、Ni、Cu、Pb和Zn具有相似的源。烧车淀土壤有机质是土壤中Cd、Ni、Cu、Pb和Zn的重要载体;除As外,土壤pH对其他重金属含量没有明显影响。烧车淀土壤重金属的剖面分布规律可能与历史时期该区域的污染情况、底泥施肥方式以及种植业和养殖业的影响有关。区内生活污水、渔业、养殖业、淀区周边工业污水等污染源可能是烧车淀土壤重金属的主要来源。

Soil profiles from 0 cm to 70 cm depth were collected from 3 sampling sites of Shaochedian Lake and total contents of these heavy metals such as As,Cr,Cd,Cu,Ni,Pb and Zn were determined to investigate their profile distribution of these heavy metals and identify their relationships and other selected soil properties in the paludified region of Baiyangdian Lake. Our results showed that both As and Cd contents at all soil layers from 3 sampling sites of Shaochedian Lake exceeded the Criteria I of soil quality guidelines in China. These heavy metals such as Cr, Ni, Cu, Pb and Zn at the entrance site were generally lower than the criteria I of soil quality guidelines in China, while they, especially Cu, Zn and Ni, exceeded the criteria I at most soil layers of both terrace and central lake sites of Shaochedian Lake. Heavy metals decreased gradually with depth along soil profiles at the entrance site of Shaochedian Lake, whereas the obvious accumulation appeared at the middle and deeper soil layers of both terrace and central lake sites. The correlation analysis showed that As and Cd in soils from Shaochedian Lake originated from different sources, but other heavy metals （i.e., Cr, Ni, Cu, Pb and Zn） had common origin. Soil organic matter was the important carrier of Cd, Ni, Cu, Pb and Zn in Shaochedian Lake. With the exception of As, soil pH values had no significant effects on other heavy metals. Profile distribution patterns of heavy metals in Shaochedian Lake were probably associated with pollution status in historical period, the application of sewage fertilization as well as planting and aquiculture. Therefore, the domestic sewage, fishery, aquiculture , and industrial sewage might be the main pollution sources of these heavy metals in soils of Shaochedian Lake.