东寨港潮间带沉积物重金属环境背景值构建研究

The construction of heavy metal environmental background values of the intertidal sediments in Dongzhai port

潮间带沉积物作为重金属污染物的源和汇,对海岸带生态环境有着至关重要的影响。本文利用海南省东寨港2个柱状沉积物样品的重金属数据,结合数理统计方法,分析沉积物中Si、Al、Fe、Ca、Li、Ba、Cu、Pb、Zn、Cd、Cr和Ni等12种元素的空间分布特征,选取了归一化重金属元素,建立了东寨港潮间带沉积物各重金属环境背景线。结果表明:柱状沉积物各元素平均值含量排序为Si(以SiO2计)>Al(以Al2O3计)>Fe(以Fe2O3计)>Ca(以CaO计)>Ba>Zn>Cr>Li>Pb>Ni>Cu>Cd,其中,SiO2、CaO、Cu和Pb的变异系数小于10%,表现为弱变异性,其它8种元素表现为中等变异强度。各元素在垂向分布上差异明显,其中沉积物SiO2含量最高,且随深度增加逐渐减小,30 cm以下的沉积物各重金属元素与Al、Fe、Ba、Li在垂向上的变化规律类似。选用Al作为归一化元素,构建了Al元素和重金属元素的一元线性回归方程,绝对系数R2大都在0.85以上,建立了区域重金属环境背景线。本文以东寨港作为中国南部特定类型沉积物代表,其沉积物重金属背景值构建为全国潮间带沉积物环境本底构建提供了有力补充,为潮间带区域的生态安全和环境安全提供基础数据支撑。

As a source and sink of heavy metal pollutants, intertidal sediments have a crucial impact on the ecological environment of coastal zones. In this paper, the spatial distribution characteristics of 12 elements in sediments, including SiO2, Al2O3, Fe2O3, CaO, Li, Ba, Cu, Pb, Zn, Cd, Cr and Ni, were analyzed by using two columnar sediment samples data of heavy metals in Dongzhai port of Hainan province, combined with mathematical statistical methods, and the environmental background lines of heavy metals in the intertidal zone sediments of Dongzhai port were established by selecting normalized heavy metal elements. The results showed that the average content sequence of all elements in the sediment was Si(base on SiO2)>Al(base on Al2O3)>Fe(base on Fe2O3)>Ca(base on CaO)>Ba>Zn>Cr>Li>Pb>Ni>Cu>Cd, among them, the variation coefficient of SiO2, CaO, Cu and Pb is less than 10%, showing weak variability, while the other 8 elements show moderate variation intensity. The vertical distribution of each element is obviously different, of which the content of SiO2 in sediment is the highest, and gradually decreases with the increase of depth, and the variation of heavy metal elements in sediments below 30 cm is similar to that of Al, Fe, Ba and Li. Al was selected as the normalized element, and univariate linear regression equation of Al element and heavy metal elements were established, whose absolute coefficients R2 were mostly above 0.85. Based on the equation, the regional environmental background lines of heavy metals were established. In this paper, Dongzhai port is taken as a representative of the specific types of sediments in southern China. The background values of heavy metals in sediments provide a powerful complement to the national background construction of intertidal sediment environment, and provide basic data support for the ecological and environmental security of intertidal zone.