黄河口潮间带表层沉积物重金属和营养元素的分布特征

Distribution characteristics of heavy metals and nutrient elements in inter-tidal surface sediments of Yellow River estuary

于2010年5月采集了5个断面的黄河口潮间带高、中和低潮滩的表层沉积物样品,对沉积物的理化性质、重金属和营养元素的空间分布特征进行了研究,并采用单因子污染指数法和综合潜在生态风险指数法,参考加拿大安大略省环境和能源部关于沉积物质量指南,对黄河口潮间带沉积物质量进行了评价。结果表明,除Cu和Pb外,其它重金属和营养元素质量分数均表现为河口北侧高于南侧;除Hg外,高、中和低潮滩的表层沉积物重金属和营养元素质量分数无显著差异,没有表现出成熟潮滩明显的垂岸分带特征。Pb质量分数高于渤海表层沉积物的高值,是该区域的首要污染因子;Hg在河口北侧近河口的两个站位低潮滩质量分数达到海洋沉积物质量一类标准的1.7和1.8倍,存在一定的潜在生态风险;TN和TOC质量分数范围在安全级别,TP质量分数在20%的站位超过最低安全级别,存在一定的安全风险。与国内其它潮滩相比,黄河口潮间带重金属Zn、Cd、Hg和As的质量分数处于较低水平,Cu和Pb质量分数处于中等水平,TOC和TP质量分数与长江口潮间带相当,TN质量分数较低。研究结果将为黄河三角洲地区生态保护、环境管理和污染治理提供基础数据。

In May, 2010, surface sediment samples were collected from the high, middle and low inter-tidal zones along five sections in the Yellow River Estuary, and analysis were carried out on their physico-chemical properties as well as the distribution characteristics of heavy metals and nutrient elements across the area. Through adopting the index number techniques of single factor and Hakanson ecological risk and referring the sediment quality standards of Environment and Energy Department in the province of Ontario, Canada, quality status of these sediments were evaluated. Results showed that concentrations of most heavy metals and nutrient elements exhibited a higher tendency in the northern bank than the southern bank, except Cu and Pb; Concentrations of heavy metals and nutrient elements showed no significant differences among high, middle and low tidal fiats except Hg, and hence no prominent vertical characteristics of a mature tidal fiat were exhibited. The concentration of Pb was higher than the maximum value of surface sediment in Bohai Sea, making it the most important pollution factor in the research area; The concentration of Hg of low tidal fiat at two stations near estuary severely exceeded the class I standard of GB 18668-2002, namely, 1.7 and 1.8 times of it respectively and possessed a certain potential ecological risk. TN and TOC were in the range of safety level, while TP at 20% stations exceeded the lowest safety level and possessed security risk to some extent. Compared with other tidal flats, the concentrations of Zn, Cd, Hg and As in sediments of the study area were at a relatively low level, those of Cu and Pb were at a moderate level; concentrations of TOC and TP were equivalent to those in the intertidal zone of Yangtze River; while that of TN was relatively low. The results of this study would supply some basic data for the ecological protection, environmental management and pollution controlling in Yellow River Delta.