海南乐东海域浅表沉积物中汞的形态分布特征研究

方超 郎春燕 王小云 孙黎 吴晓蓉 周莉

摘 要：采用改進的Tessier法及王水消解法，以冷原子荧光技术对海南乐东海域10个浅表沉积物中总汞及各形态汞进行了测定。系统考察了高锰酸钾对提取液中汞的氧化条件。样品中各形态汞的检出限范围为0.000 3～0.002 7 μg/g，总汞检出限为0.002 1 μg/g，各形态汞之和与总汞的百分比范围为92.2%～115%。2个海洋沉积物标准物质（GBW07314，GBW07334）总汞及各形态之和的测量值均与参考值吻合。除离子交换态和碳酸盐结合态因含量太低而导致RSD大于10 %以外，其他3个态的RSD范围均在2.7%～6.7%之间。9个样品总汞含量均未超过我国海洋沉积物质量第1类标准。各形态汞占总汞的平均百分比顺序为：残渣态>铁锰氧化态 > 有机结合态 > 碳酸盐结合态 > 离子交换态，前三个态之和占到94.25%，后两个态仅占5.75%。总汞与铁锰氧化态和残渣态之间均具有显著相关性，后两种形态控制了总汞在不同海水深度下的走势。

关 键 词：海南;沉积物;汞形态

中图分类号：O 657 文献标识码： A 文章编号： 1671-0460（2015）06-1268-04

Distribution of Mercury Species in Marine Surface Sediments

in Hainan Ledong Offshore

FANG Chao， LANG Chun-yan， WANG Xiao-yun， SUN Li， WU Xiao-rong， ZHOU Li

（College of Materials and Chemistry & Chemical Engineering，Chengdu University of Technology，

Sichuan Chengdu 610059， China）

Abstract： Total mercury and mercury species in surface sediments from Hainan Ledong offshore were determined by CV-AFS after aqua regia digestion and extraction with improved Tessier method. The influence of KMnO4 on oxidation of mercury in extraction process was systematically investigated. The results show that the detection limits of mercury species are in the range of 0.000 3 ～ 0.002 7 μg/g and total mercury of 0.002 1 μg/g. The percentages of the sum （of Hg species ） of total Hg are in the range of 92.2%～115%. The measured values （total and sum of species） of mercury in marine reference materials are in good agreement with the recommended values. The RSDs of exchangeable Hg and Hg bound to carbonates are more than 10% due to their lower concentrations， the RSDs of the other three Hg species are in the range of 2.7% ～ 6.7%. The contents of total Hg in nine of the ten samples dont exceed the national qualityⅠstandard for marine sediment. The average percentages of individual Hg species of total Hg follows： residual Hg > Hg bound to Fe-Mn oxides > Hg bound to organic matter > Hg bound to carbonate > ion exchangeable Hg， the sum of the first three species are 94.25% and the last two species are 5.75%. There are significant correlations between total Hg and Hg bound to Fe - Mn oxide & residual Hg， the last two species control the trend of total mercury in seawater at different depths.

Key words： Hainan; Sediment; Mercury species

汞及其化合物以其极高的毒性、流动性和生物富集性以及广泛的来源，而成为目前全球优先污染物之一[1]。沉积物既是重金属污染物的汇聚场所也是其潜在的来源。海洋沉积物中汞的含量和形态分布，不仅可以在一定程度上反映所在海域的污染情况，更能反映出汞的迁移转化能力、毒性和生物有效性[2，3]。

近年来，Covelli等[4]对工矿业影响较大的意大利亚得里亚海marano泄湖、Leonard Boszke等[5]对泰国海啸受灾海域、Parthasarathi Chakraborty等[6]对印度人口及贸易最集中的中央东海岸、Ef……