鄱阳湖典型湿地土壤-植物系统重金属沿湖向富集及迁移转换特征分析  

Enrichments,Migrations,and Conversions of Heavy Metal in the Soil/Sediment-Plant System Towards the Lake in Typical Poyang Lake Wetland

作　　者：曾欢 张华[1,2] 丁明军[1,2] 王鹏[1,2] 黄高翔[1,2] 彭翔 秦瑗 杨越 邹天娥 徐欢 黄鹏 ZENG Huan;ZHANG Hua;DING Ming-jun;WANG Peng;HUANG Gao-xiang;PENG Xiang;QIN Yuan;YANG Yue;ZOU Tian-e;XU Huan;HUANG Peng(School of Geography and Environment,Jiangxi Normal University,Nanchang 330022,China;Key Laboratory of Poyang Lake Wetland and Watershed Research,Ministry of Education,Jiangxi Normal University,Nanchang 330022,China)

机构地区：[1]江西师范大学地理与环境学院,南昌330022 [2]江西师范大学鄱阳湖湿地与流域研究教育部重点实验室,南昌330022

出　　处：《环境科学》2023年第2期781-795,共15页Environmental Science

基　　金：国家自然科学基金项目(4206010185);江西省师范大学鄱阳湖湿地与流域研究教育部重点实验室开放基金项目(PK2019003)。

摘　　要：特殊的水文节律导致鄱阳湖形成面积较大的周期性环湖消落带,大量的营养物质和污染物极易在消落带中发生沉积,选择鄱阳湖典型河口型消落带,沿湖向按照不同植被类型设置采样断面,采集土壤-沉积物和优势植物样品(不同组织),分析不同时空下土壤/沉积物和优势植物体中重金属(Cr、 Ni、 Cu、 Zn、 As、 Cd、 Sb和Pb)的含量特征及富集水平,并进一步分析土壤-植物系统中重金属的迁移转换特征,揭示鄱阳湖典型消落带土壤-植物系统重金属迁移转换的影响因素.结果表明,消落带土壤/沉积物重金属含量沿湖向表现为明显的分布规律,呈现为先升高后降低的分布特征,即季节性淹水带土壤/沉积物是重金属富集的主要地带,Cu、 Pb和Sb在土壤/沉积物中的富集水平较高,其中Cu和Sb为显著富集(EF>5);潜在生态风险结果表明季节性淹水带总体处于轻度生态危害水平(70≤RI<140),显著高于淹水带和未淹水带.消落带沿湖向带状分布的优势植物体中重金属含量并未表现出显著的空间分布特征,但表现为显著的季节差异,生长季(4月)优势植物体内重金属具有较高的含量水平,重金属不同介质和组织的分配大体遵循基质>根部≥地上部分的分布特征,但根部Cd含量显著高于沉积物/土壤中Cd的含量,Sb含量在三者间差异不显著.消落带优势植物生物富集因子(BAF)与转移系数(TF)并未表现出明显的空间分布规律,其中未淹水带茵陈蒿具有较高的BAF和TF值;利用RDA综合排序发现,pH、有机碳、株高和铁锰氧化物是影响土壤-沉积物-优势植物迁移转换的关键环境因子.研究结果可为鄱阳湖典型湿地生物多样性和重金属污染防治提供科学依据和理论支撑.A large area of periodic water-level-fluctuating zone(WLFZ) in the Poyang Lake,regulated by a special hydrologic rhythm,was deposited with significant amounts of nutrients and pollutants.In this study,the WLFZ located in a typical estuarine wetland was chosen and sampling transects were arranged according to different vegetation types towards the lake.Soil/sediment and dominant plant(different tissues) samples were collected,and contents and enrichment levels of heavy metals(Cr,Ni,Cu,Zn,As,Cd,Sb,and Pb) in these samples were analyzed.The migrations and conversions of heavy metal in the soil/sediment-plant system were evaluated,and driving environmental factors were explored.The results indicated that the contents of heavy metal in the soil/sediment presented an obvious single-peak distribution towards the lake,that is,the seasonally flooded zone was identified as the main deposited zone of heavy metals.There was a high enrichment level of Cu,Pb,and Sb in the soil/sediment from the WLFZ,and significant Cu and Sb pollution was identified(EF>5).The results from the potential ecological risk evaluation(RI) indicated that the ecological risk of the seasonally flooded zone was significantly higher than that in the flooded and unflooded zones,being at a low ecological risk(70≤RIroot ≥ above-ground part,except for in Cd and Sb.The Cd content in the roots was significantly higher than that in the sediment/soil,and the Sb concentration was not significantly different among the three tissues.The bio-enrichment coefficient(BAF) and transfer factor(TF) of heavy metal in the dominant plant towards the lake did not show an obvious spatial pattern,and BAF and TF of heavy metals in the Artemisia capillaris Thunb.was higher than those in other dominant plants.The RDA revealed that pH,organic matter,plant height,and Fe-Mn oxides were the key environmental factors driving the migrations of heavy metals in the soil/sediment-plant system.These results will provide scientific basis and theoretical support for the biodiversity conse

关 键 词：鄱阳湖 消落带 季节性淹水带 土壤/沉积物-植物系统 重金属 迁移转换 

分 类 号：X524[环境科学与工程—环境工程]