Spatial and Seasonal Variations of Heavy Metals in Wetland Soils of the Tidal Flats in the Yangtze Estuary, China: Environmental Implications

作     者：HU Xue-Feng DU Yan FENG Jian-Wei FANG Sheng-Qiong GAO Xiao-Jiang XU Shi-Yuan 

作者机构：Department of Environmental Science and Engineering School of Environmental and Chemical EngineeringShanghai University Department of Environmental Science and Engineering Fuzhou University Department of Environmental Science and Engineering Fudan University Department of Geography East China Normal University 

出 版 物：《Pedosphere》 (土壤圈（英文版）)

年 卷 期：2013年第23卷第4期

页      面：511-522页

核心收录：

学科分类：12[管理学] 1204[管理学-公共管理] 082803[工学-农业生物环境与能源工程] 08[工学] 0828[工学-农业工程] 0818[工学-地质资源与地质工程] 0903[农学-农业资源与环境] 0901[农学-作物学] 120405[管理学-土地资源管理] 

基　　金：Supported by the National Natural Science Foundation of China (Nos. 41130526, 40971126, and 40771093) the Shanghai Leading Academic Discipline Project of China (No. S30109) 

主　　题：clay fraction grain-size characteristics intertidal soils pollutants sedimentary environments 

摘      要：The environment of estuarine wetlands has been attracting worldwide attention. To study the spatial distribution of pollutants in the tidal flats of the Yangtze Estuary, Southeast China, the Eastern Tidal Flat of Chongming Island (EC) and the Jiuduansha Shoal (JS) of the estuary were selected as the study sites. At each of the two sites, a cross-transect from land to sea was established and topsoil and soil core samples in the cross-transect were collected spatially and seasonally to determine their contents of heavy metals (Cu, Zn, Pb, Cd, Cr, Ni, Mn, and Fe) and grain-size characteristics. The results showed that the heavy metal loads were commonly higher in the soils of nearshore high tidal flats and had a tendency of decreasing from land to sea at both of the study sites. The contents of heavy metals in the soils of the high and medial tidal flats were mostly higher in April and November but lower in July. Corresponding spatial and seasonal variations in grain size of the intertidal soils were also observed at the two study sites. The soils in the nearshore high tidal flats were finer and gradually got coarser seawards; they were relatively finer in April and November but coarser in July. Furthermore, the contents of heavy metals in the intertidal soils of both the sites EC and JS were significantly positively correlated with the clay (63 μm) and 20-63 μm fractions, which suggested that the heavy metals in the intertidal soils were primarily combined with the fine particulate fraction (20 μm), especially clay, and hence the spatial and seasonal variations in heavy metals were actually caused by the change of the grain-size characteristics of the intertidal soils due to the different sedimentary environments in the estuary. The results of this study may also contribute to a better understanding of the soil formation and classification in the tidal flats of the Yangtze Estuary.