【作者】 李富祥；

【导师】 李雪铭；

【作者基本信息】 辽宁师范大学 ， 自然地理学， 2012， 博士

【摘要】 本文通过在鸭绿江口进行的海洋地质与地球物理调查,获得了大量沉积物样品和实测数据。通过对表层和剖面沉积物的粒度、碎屑矿物、重金属元素和生源要素的实验室分析,结合剖面沉积物²¹⁰Pb沉积速率测定。研究粒度、碎屑矿物、重金属元素和生源要素在沉积物中的横向和垂向变化特征,探讨了鸭绿江口沉积物的沉积特征、来源及输运过程,分析评价了鸭绿江口环境污染现状、污染物来源及环境演变过程。本文研究主要得到以下几方面成果：对河口不同地区表层沉积中的粒度、碎屑矿物的分布特征的研究,探讨了河口不同地区表层沉积物的来源及输运过程；对重金属元素在不同地区的分布情况及其与粒度之间相互关系的研究,探讨了重金属的来源和沉积环境；采用不同评价方法对重金属污染评价的研究,分析了河口不同地区表层沉积物重金属的污染程度及主要污染因子；对剖面沉积物中的粒度、碎屑矿物、重金属元素和生源要素的研究,得到近百年尺度的河口地区沉积环境变化过程及环境污染的演变过程。本文研究主要得出以下几方面的结论：粒度研究结果显示鸭绿江河口地区表层沉积物来源并不是单一的,而是具有多元性和空间差异性,其表层沉积物底质类型主要为砂、粉砂质砂、砂质粉砂和极少量黏土质粉砂。鸭绿江径流输沙作用在河口地区表现非常明显,同时也伴随着潮汐和波浪引起的浅海沉积物向陆运动,因此河口地区表层沉积物物源存在着多样性。鸭绿江下游地区和中水道沉积物来源主要为河流输送,河流径流作用明显；西水道、辽东浅滩的沉积物来源既有河口输送又有浅海表层沉积物的向陆运动,受河流径流和海洋潮汐、波浪的双重影响。碎屑矿物研究结果显示鸭绿江河口地区具有指“相”性意义的特征矿物包括重矿物中的榍石、红柱石、十字石、蓝晶石和轻矿物中的玻璃质凝灰物,指“相”性矿物的分布特征和碎屑矿物特征指数的变化,表明鸭绿江河口的表层沉积物与毗邻浅海的表层沉积物具有不同的物源。鸭绿江下游地区与中水道的沉积以河流作用为主,属于河流现代沉积；西水道和辽东浅滩受河流和浅海双重作用影响。重金属研究结果表明鸭绿江口重金属主要来源于工业和农业的污染物排放,各重金属元素之间有着较为一致的来源与沉积环境,对鸭绿江口重金属污染生态风险评价贡献率比较高的重金属污染因子是Cu、Cd和Hg。生源要素的研究结果表明其主要来源是工业和农业污染物排放、土地开发、生活污水等；生源要素与除Cu以外的重金属元素有着极高的相关性,表明生源要素和重金属元素有着较为一致的来源与沉积环境剖面沉积物的研究结果显示鸭绿江河口地区的环境演变过程可分为3个阶段：第一阶段为1941年水丰水库建成以前,这一时期污染物含量变化幅度较大,究其原因是因为没有水库拦截,鸭绿江径流年度变化很大；第二阶段为水丰水库建成以后到上世纪80年代初,由于水库的截留作用,鸭绿江年径流量变化幅度较小,污染物含量变化也相对较小；第三阶段为80年代中后期至今,污染物含量由于工农业和城市建设污染物的大量排放出现明显增加趋势。更多还原

【Abstract】 A large number of sediment sampling and measured data was got by the Marine geological and geophysical survey in Yalu River estuary. Through the lab analysis to grain size、detrital mineral heavy metals and biogenic elements in surface sediment and core sediment, and combining with the measurement of sedimentation rates in the core sediment of by210Pb,The paper researched horizontal and vertical variation characteristics of grain size、 detrital minerals、heavy metals and biogenic elements in the sediment, discussed the sedimentary characteristics、sources、transportation process, analyzed the status of environmental pollution、the source of pollution and the evolution processes of environmentThe research of this paper got the following achievements:Researched the distribution characteristics of grain size and detrital minerals in the surface sediment of different zone in Yalu River estuary, and discussed the sources and transport process of surface sediment in different regions.Researched the distribution of heavy metals and the relationship between heavy metals and grain size in different zones, and discussed the sources and sedimentary environment of heavy metals.Evaluated the pollution condition of heavy metals using different assessment methods, and discussed the pollution levels and main pollution factors of heavy metals.Researched the rain size、detrital minerals、heavy metals and biogenic elements in core sediment, and got the change process of sedimentary environment and evolutionary process of environmental pollution in Yalu River estuary in recent century.The research of the paper got the following results:The research results of grain size showed that the source of surface sediment in Yalu river estuary was not single, but had diversity and spatial distribution, and that its surface sediment types were mainly S, ST, TS and very few TS. The sediment transport by runoff of Yalu River is very apparent in the estuary area, and together with the sediment of the shallow sea’s movement to land caused by the tides and waves, so the sediment source of the estuary surface was diversity. The sediment source of the Yalu River downstream area and middle water way was mainly for the river transportation, and the river runoff effect was obvious; The sediment source of west waterway and Liaodong shallow beach were both estuary transportation and the sediment movement of the shallow sea surface to land under the double influence of the rivers runoff and the ocean tide and waves.The research results of detrital minerals showed that the sumptomatic mineral t in the Yalu River estuary areas included the heavy mineral including sphene, andalusite, grenatite, kyanite and the light mineral-vitreous ash, and the distribution characteristics of and characteristic index change of detrital mineral showed that the surface sediment of the Yalu River estuary and of the shallow sea surface had different material sources. The Yalu River downstream area and the East waterway deposition gave priority to river function, and that was river modern sedimentary,then West water channel and the Liaodong shallow beach were affected by the double influence of the rivers and shallow sea.The study results of the heavy metal showed that the heavy metal of the Yalu river estuary mainly came from the industrial and agricultural pollutant discharge, and there was a more consistent source and sedimentary environment among the heavy metal element, then the heavy metal pollution factor with higher ecological risk assessment contribution rate to the metal pollution of the Yalu river estuary was Cu, Cd and Hg.The study results of biogenic elements showed that its main source was the industrial and agricultural pollutant emissions, land development, domestic sewage, etc; Biogenic elements had a high correlation with heavy metal element except Cu, and biogenic elements and heavy metal elements had a consistent source and sedimentary environment.The core sediment’s research results showed that the environment evolution process of the Yalu river estuary area could be divided into three stages:the first stage was before Shui Feng water reservoir built in1941, and pollutant content rangeability was larger, then by reason of no reservoir interceptor, the runoff’s annual change of the Yalu river was very large; The second stage for Shui Feng Water Reservoir built by the early1980s, because of the reservoir’s interception effect, the annual runoff rangeability of the Yalu river was small, and pollutant content change was also relatively small; The third stage is from Later1980s to now, pollutant content appeared an obvious increasing trend because of large amounts of pollutant emission from agriculture, industry and urban construction.更多还原