黄河口及其附近海域砷的分布，沉积物中砷的生物可利用性及粒度校正的研究

IOCAS-IR > 海洋环流与波动重点实验室

	黄河口及其附近海域砷的分布，沉积物中砷的生物可利用性及粒度校正的研究
	高兴梅
学位类型	博士
	1990
学位授予单位	中国科学院海洋研究所
学位授予地点	中国科学院海洋研究所
摘要	氮、磷、砷在周期表中位于同一主族，氮和磷是营养元素，而砷却是有毒的元素。砷在海水中有三价、五价二种存在形式。它们是如何分布变化的？它在沉积物中的含量与底栖生物是否有关？黄河口是我国研究得较少的一个海区，带着上述问题，我们于1989年5月（枯水期）和8月（丰水期）进行了二个航次的调查。除得到了砷在海水、沉积物中的分布外还得到如下结果：一、黄河口区三价和五价砷的平均含量如表所示：在热力学平衡时，海水中的砷主要应以砷酸盐（五价）形式存在。但黄河口区三价砷的存在量点总砷的0－70％。通过与叶绿素a的相关分析得知，三价砷是浮游植物产生的。但在低温时（低于13℃），即使浮游植物量很高也不产生三价砷。二、沉积物中砷的含量与沉积物的粒径有关：细粒径的沉积物含砷较高。粗粒径的沉积物含砷较低。但在河口，由于流速大沉积物多为粗粒径的。河水中砷含量比海水高，而河口沉积物中砷含量往往比附近海区沉积物中的低，不能反映河水中砷高的情况，为此做了沉积物比表面的较正，前人用比表面校正时发现比表面和重金属含量在低表面时呈线性关系，随着比较表面增大，重金属含量不再增加，我们认为沉积物可以分成二部分：一部分是岩石碎屑、粘土矿等组成，这部分中的砷是生物不能吸收利用的“非活性”部分；另一部分是水合氧化物、有机质等组成的，其中的砷能被生物摄取（“活性”部分），而且也只有“活性”部分才是和沉积物比表面有关。通过研究得到以下有意义的结果：1、用1MHCl提取沉积物中的“活性”砷，其含量和相应位置采集到的四角蛤蜊（Mactra Veneriformis Reeve）中砷含量具有良好的线性关系。说明对砷来说1MHCl和四角蛤蜊消化液具有同样的效力。2、沉积物外比表面和“活性”砷之间有很好的线性关系。我们提出了以每平方米沉积物外表面积含活性砷量作为沉积物中砷的评价单位，克服了沉积物粒径不同的影响。上述方法可以推广到沉积物中其它污染物质的研究上去。上述方法对制订沉积物的环境质量标准是有参考价值的，因为环境质量标准是要以生物的毒理试验为依据的。
其他摘要	Different from nitrogen and phosphorus, both known as nutrient elements, arsenic (As), existing in +5, As(V), and, +3, As(III) in marine environment, is a typical poisonous element, although they belong to the same group of the Periodic Table. Yellow River is the second largest river in China in terms of length but the largest river in the ability of solid material transportation, which makes the Yellow River Estuary one of the most intereting arcas for studies of distribution, participation, grain-size offect correction, and bioavailability of As. During two cruises (May and August, 1989)in the Yellow River Estuary area, we investigated the participation, transformation, grain-size effect correction, and the distribution of arsenic in water, sediment, and the relationship between As contents and in a benthic mollusc, Mactra Veneriformis (Reeve). The results of our investigations are reported as follows: 1. The contents of As(III), As(V), and dissolved As in the Estuary waters are summarized in Table 1. Table 1. Average contents of As in Yellow River Estuary water The dominant form of As in seawater should be As(V) at a thermodynamical equilibrium. But As(III) content is much greater than that could be accounted for by thermodynamic equilibrium in Yellow River Estuary area. The ratio of As(III) to dissolved As is 0-70%. The strong correlation between As(III) and Chlorophyll a indicates that As(III) may be produced/transformed by phytoplankton (at the temperatures above 13℃). 2. The contents of 1M-HCl extractable As in sediments has stong correlation with the As contents in Mactra Veneriformis, a benthic mollusc, indicates that 1M-HCl extractable As seems to be the "bioavailable" for of As in the sediments. 3. The ratio of "bioavailable" As in weight (ng)/extra surface area in m~2 is a constant because of the excellent correlation between the extra specific surface area and the contents of "bioavailable" As (1 M-HCl extractable) in uncontaminated sediments from the same origin. This constant can be used in assessing As contents in marine sediments and this correction method is better than ≤16um extrapolation from grain-size distribution correction. The above mentioned area correction method may be also valid for other heavy metals in evaluating marine environment, qualities and making marine sediment criterion or standards. 4. Extra specific surface area correction is necessary for comparison and evaluation of participation and distribution of As in sediments and related waters, by which we can explain why higher As contents in water near the River mouth is related to lower As levels (in weight/weight bases, not in weight/surface area bases).
页数	96
语种	中文
文献类型	学位论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/981
专题	海洋环流与波动重点实验室
推荐引用方式 GB/T 7714	高兴梅. 黄河口及其附近海域砷的分布，沉积物中砷的生物可利用性及粒度校正的研究[D]. 中国科学院海洋研究所. 中国科学院海洋研究所,1990.

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