【作者】 单长青；

【导师】 单红仙； 刘汝海；

【作者基本信息】 中国海洋大学 ， 环境工程， 2006， 硕士

【摘要】 汞是一种全球性污染物,具有很高的毒性,易在环境中发生甲基化,并在生物体内累积、放大,危害生态系统健康,环境汞污染问题自20世纪50年代日本“水俣病”事件以来,一直是环境科学领域的热点问题之一。汞及其化合物污染范围广,危害大,难治理,一个重要的原因就是汞在环境中易发生迁移和转化,汞在土壤-大气、水体-大气和植物-大气等介质之间的迁移转化规律已经有了较多的研究,本文则以胶州湾海泊河口和李村河口为例,研究了其沉积物中的汞在不同环境条件下向水体和大气的释放特征。胶州湾是一个半封闭的海域,其东部的海泊河口和李村河口污染尤为严重,沉积物中汞的含量分别高达5.62μg /g和2.92μg /g。pH值、温度、沉积物厚度以及光照等多种环境因素均会影响汞向上覆水的释放。当pH<7时,沉积物-海水汞的释放速率、最大释放量和最大释放率均随pH值的升高而降低,当pH>7时,则随pH值的升高而升高;汞的释放随着海水温度的升高而增强;对上覆水影响较大的是较薄的表层沉积物,测定的海泊河口和李村河口沉积物的有效厚度分别为3.0cm和2.5cm左右,在有效厚度范围内,汞向上覆水的释放速率和释放量随沉积物厚度的增加而增加,汞的释放率随沉积物厚度的增加而降低;光照下沉积物中的汞向海水的释放量大于遮光下。实验结果表明在模拟条件下汞向上覆水的释放趋于平衡时,上覆水汞含量一般可增加几个μg /L,对海水水质产生较大的影响。汞的释放动力学数据与常用模型的拟合结果表明,除动力学一级方程外,双常数方程、Elovish方程、抛物线扩散方程、Ho的一级动力学方程和Ho的二级动力学方程都能够很好的描述汞的释放动力学过程,在0.05水平上显著相关,其中与Ho的二级动力学方程拟合的结果最好,在0.01水平上显著相关。落潮时光照下河口沉积物中的汞会快速释放到大气中,其释放通量一天之中遵循先升高后降低的规律,在正午左右达到最大值。光照8h后,海泊河口和李村河口沉积物汞的释放率夏季分别为58.3%和52.4%,冬季分别为18.5%和27.1%,汞的平均释放通量夏季分别为1300μg/(m2·h)和900μg/(m2·h),冬季分别为613μg/(m2·h)和466μg/(m2·h),夏季高于冬季。更多还原

【Abstract】 Mercury is a global pollutant with high toxicity. Inorganic mercury can be easily changed into methymercury, and accumulated in life bodies. The toxicity is enlargem-ented, so it has a serious influence on ecosystem. Since the 1950’s Minamata Disease in Japan, the mercury pollution is always a concerning question in the environment science field. Mercury pollution appears widely and can’t be easily disposed, mainly because mercury and its compounds can easily transport and transform in the environments. Many scholars have researched mercury transport from the soil to the atmosphere, the water to the atmosphere, and the vegetation to the atmosphere. UsingHaipo Estuary and Licun Estuary sediments in Jiaozhou Bay, we discuss the releasing of mercury from the estuary sediment to the upper water and the atmosphere. Haipo and Licun Estuary were polluted heavily in the east of Jiaozhou Bay. The mercury concentrations were 5.62μg /g and 2.92μg /g respectively. Some factors such as pH, temperature, depth of the sediment and solar radiation affected the release of mercury from sediment to upper water. When pH <7, the release rate, content and percentage of mercury decreased following the increase of pH, and when pH >7, they increased following the increase of pH. The release of mercury increased following the increase of temperature of seawater. The release of mercury was related to the depth of sediment. The effective depth of Haipo and Licun Estuary Sediment were 3.5cm and 2.5cm respectively. Within the effective depth, the release content increased and the release rate decreased following the increase of sediment depth. The release content of mercury to the upper water increased under solar radiation. When the release of mercury reached a balance, the mercury of upper water could usually contain severalμg /L. This heavily affected the intertidal seawater of Jiaozhou Bay.Mercury release fitted to the First-order equation, the Double constant equation, the Elovish equation, the Parabola diffusion equation, the Ho’s first-order equation and更多还原