CAJ | 학술논문

为了解岷江下游不同林分类型土壤重金属的含量特征和污染状况，以岷江下游（五通桥段）小型集水区水杉（Metasequoia glyptostroboides）人工林、杉木（Cunninghamia lanceolata）人工林、巨桉（Eucalyptus grandis）人工林、阔叶混交林4种林分类型为研究对象，分析林地土壤不同层次（0~10、10~40、40~80 cm）5种重金属（As、Cd、Cu、Pb、Zn）含量，采用综合污染指数法对各林分类型土壤重金属进行评价，利用相关分析和聚类分析对其来源进行初步解析。结果表明：集水区中4种林分类型土壤中重金属As、Cd、Cu、Pb和Zn的平均浓度分别为6.57、0.36、14.20、24.69、162.65μg·g-1。土壤总体pH值为4.73~6.49，呈酸性，有机质含量为4.32~19.72μg·g-1，重金属As和Cd含量与土壤pH值为显著负相关，5种重金属相互之间呈极显著正相关关系，与有机质也为极显著正相关关系。总体上4种林分类型土壤重金属含量随土壤深度的增加而降低，表层土Cd污染最严重，只存在轻微的As、Pb和Zn污染，但都未受到Cu的污染。杉木人工林和水杉人工林重金属高于阔叶混交林和巨桉人工林。土壤重金属潜在生态危害程度顺序均为：Cd>Pb>As>Cu>Zn。4种林分类型土壤重金属综合潜在的生态风险指数（RI）的范围为：102.11~247.05。表层土潜在的生态危害等级均为中等，下层土潜在的生态危害等级为中等或轻微。源解析的结果表明集水区林地土壤重金属含量受到自然源和人为源的双重影响，其中Cu主要来自成土母质，As和Cd主要来自农业生产，Pb主要来自采矿业，Zn同时受到采矿业和农业生产等的影响。
위료해민강하유불동림분류형토양중금속적함량특정화오염상황，이민강하유（오통교단）소형집수구수삼（Metasequoia glyptostroboides）인공림、삼목（Cunninghamia lanceolata）인공림、거안（Eucalyptus grandis）인공림、활협혼교림4충림분류형위연구대상，분석임지토양불동층차（0~10、10~40、40~80 cm）5충중금속（As、Cd、Cu、Pb、Zn）함량，채용종합오염지수법대각림분류형토양중금속진행평개，이용상관분석화취류분석대기래원진행초보해석。결과표명：집수구중4충림분류형토양중중금속As、Cd、Cu、Pb화Zn적평균농도분별위6.57、0.36、14.20、24.69、162.65μg·g-1。토양총체pH치위4.73~6.49，정산성，유궤질함량위4.32~19.72μg·g-1，중금속As화Cd함량여토양pH치위현저부상관，5충중금속상호지간정겁현저정상관관계，여유궤질야위겁현저정상관관계。총체상4충림분류형토양중금속함량수토양심도적증가이강저，표층토Cd오염최엄중，지존재경미적As、Pb화Zn오염，단도미수도Cu적오염。삼목인공림화수삼인공림중금속고우활협혼교림화거안인공림。토양중금속잠재생태위해정도순서균위：Cd>Pb>As>Cu>Zn。4충림분류형토양중금속종합잠재적생태풍험지수（RI）적범위위：102.11~247.05。표층토잠재적생태위해등급균위중등，하층토잠재적생태위해등급위중등혹경미。원해석적결과표명집수구임지토양중금속함량수도자연원화인위원적쌍중영향，기중Cu주요래자성토모질，As화Cd주요래자농업생산，Pb주요래자채광업，Zn동시수도채광업화농업생산등적영향。
In order to understand the soil heavy metal pollution characteristics in soils of different forest stands at the downstream of Minjiang River, soil samples at the depth of 0~10, 10~40 and 40~80 cm were collected from four forest types (i.e., Metasequoia glyptostroboides plantation, Cunninghamia lanceolata plantation, Eucalyptus grandis plantation, and broad leaved mixed forest). As, Cd, Cu, Pb and Zn concentration in the soil samples were analyzed, and the comprehensive pollution index was used to assess pollution status in different forest stands. Both correlation analysis and hierarchical cluster analysis were conducted to identify the sources of heavy metals in the soils of forest stands. The results showed that average concentration of As, Cd, Cu, Pb and Zn in soils of 4 types of forest stands at the catchment were 6.57, 0.36, 14.20, 24.69 and 162.65μg·g-1, respectively. The pH with a range of 4.73~6.49 indicated that the soils were acid, and the organic matter content was from 4.32 to 19.72μg·g-1. There was a significant negative relationship between pH and As or Cd concentration; an extremely significant positive relationship between any of five heavy metal concentration and the organic content in soils, and an extremely significant positive relationship among five heavy metals were observed. In generally, the concentration of heavy metals decreased with the increase of soil depth. Surface of soils was polluted most heavily by Cd, slightly polluted by As, Pb and Zn, but not polluted by Cu in all types of forest stands. There were higher concentrations of heavy metals in the soils of M. glyptostroboides and C. lanceolata plantation than that in the soils of E. grandis plantation and broad leaved mixed forest. The potential ecological risk were in the order of Cd>Pb>As>Cu>Zn. The range of potential ecological risk index (RI) was 102.11~247.05 in above four types of forest stands. Ecological risk in the soil surface was medium, and that in subsoil was medium or slight. Hierarchical cluster analysis based on Pearson correlation coefficients suggested that the heavy metals in the forest stands of the catchment were originated from both soil parent rock and external sources related to human activities. Specifically, Cu was largely originated from soil parent materials, As and Cd were from the process of agricultural production, Pb might originate from mining and metal processing, Zn probably derived from agricultural production, mining or metal processing.