厦门西港近岸沉积物中重金属元素背景值的确定

重金属环境背景值是评价环境中重金属污染和制定环境质量标准的前提和基础,为确定厦门西港近岸海域沉积物中重金属元素的背景值水平,以厦门西港近岸海域柱状沉积物样品为研究对象,对不同深度沉积物样品的重金属元素含量进行测定,在分析重金属元素垂直分布特征的基础上,筛选未受人为活动影响的沉积层位,根据数据分布类型计算得到17种重金属元素的背景值(范围):Sc 13. 85(11. 52～16. 69)、V 101. 03(94. 61～107. 45)、Cr 63. 50(55. 00～69. 20)、Co 14. 62(13. 70～15. 54)、Ni 29. 92(27. 23～32. 54)、Cu 21. 48(17. 95～25. 01)、Zn 118. 81(96. 39～141. 23)、Pb 41. 80(38. 41～57. 35)、Sr 97. 78(93. 22～102. 34)、Mo 1. 39(0. 59～2. 19)、Sb 0. 58(0. 53～0. 63)、Ba 407. 00(378. 15～427. 00)、Tl 0. 93(0. 72～1. 05)、Bi 0. 71(0. 51～0. 82)、Fe 32 610. 27(19 903. 73～53 428. 67)、Mn 393. 20(306. 67～793. 63)、Cd 0. 066(0. 056～0. 076) mg/kg。以上背景值与福建省海岸带土壤、厦门A层土壤、中国陆壳、中国浅海沉积物和全国水系沉积物元素背景值相比,总体上比较接近,但Sr含量略低,Pb和Zn含量略高,说明可信度较高且具有地域性。影响厦门西港近岸海域沉积物中重金属元素背景值的主要因素是陆源物质、沉积物粒度和地球化学特征。

Determination of Background Values of Heavy Metals in Coastal Sediment of the Western Bay, Xiamen

The environmental background values of heavy metals are the premise and basis for evaluating environmental pollution of heavy metals and setting environmental quality standards. In order to determine the background values of heavy metals in sediment of the Western Bay coastal area of Xiamen, sediment cores were sampled and contents of heavy metals in sediments from different depths were determined. The segments in sediment cores received no influence from human activities were screened and the background values of heavy metals of the study area were determined on the basis of vertical distributions of heavy metals in sediment cores. The results showed that background values (ranges) of heavy metals are respectively Sc 13.85 (11.52-16.69), V 101.03 (94.61-107.45), Cr 63.50 (55.00-69.20), Co 14.62 (13.70-15.54), Ni 29.92 (27.23-32.54), Cu 21.48 (17.95-25.01), Zn 118.81 (96.39-141.23), Pb 41.80 (38.41-57.35), Sr 97.78 (93.22-102.34), Mo 1.39 (0.59-2.19), Sb 0.58 (0.53-0.63), Ba 407.00 (378.15-427.00), Tl 0.93 (00.72-1.05), Bi 0.71 (0.51-0.82), Fe 32 610.27 (19 903.73-53 428.67), Mn 393.20 (306.67-793.63), Cd 0.066 (0.056-0.076) mg/kg. Compared with background values in coastal soils of Fujian, surface soils of Xiamen, continental crust of China, shallow sea sediments of China and drainage sediments of China, the content of Sr is slightly lower while the contents of Pb and Zn are slightly higher, indicating that above background value data are regional and credible. The main factors of affecting background values of heavy metals in sediments of the Western Bay coastal area of Xiamen are terrestrial material, sediment grain size and geochemical characteristics.