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1.
厦门湾颗粒活性污染物归宿的研究   总被引:2,自引:0,他引:2  
陈敏  黄奕普 《海洋学报》1998,20(5):70-74
采用条件分配系数Kd作为量度污染物颗粒活性强弱的基准,结合234Th-238U不平衡确定的颗粒物停留时间以及水体的停留时间,建立了一个简单的模型用于预测具有不同Kd值的污染物在厦门湾的归宿,该模型最终确定了某一污染物进入该海域后迁出至沉积物与离开该海域进入外海水之相对份额大小。污染物质的最终归宿通常依赖于其本身的化学性质、环境中的颗粒动力学性质及水动力作用,忽略其中任何一个因素都是不合适的。  相似文献   

2.
A wide variety of substances, including known or potential pollutants, become associated with particles in coastal marine environments. This association may result from: (1) ion exchange, precipitation, or hydrophobic interactions with the particle surface, (2) co-precipitation with iron and manganese hydrous oxide coatings, (3) complexation with organic substances bound or aggregated with particles, (4) incorporation into mineral lattices, organisms or fecal material, or (5) flocculation of colloidal organic and inorganic matter during river and sea water mixing. The transport, accumulation and fate of such chemically-reactive pollutants in coastal marine environments are governed to a great extent by particle dynamics. Understanding of the mechanisms and processes affecting pollutant-particle associations and dynamics allows the prediction of the fate of a wide variety of pollutants in estuarine, coastal and marine environments.  相似文献   

3.
利用234Th-238U不平衡研究南海东北部海域3个站位上层水体中的颗粒动力学性质,测定了水往中溶解态及颗粒态234Th的比活度,具体讨论各相中234Th/238U)AR(放射性活度比)比值的垂直分布情况及其与水化学要素间的关系。运用稿态箱式模型计算出各站位不同水层中溶解态234Th相对于清除至颗粒物的平均停留时间和颗粒态234Th相对于迁出作用的停留时间。由模型得出的参数表明3个站位的真光层具有两种不同的层化图像,这一情形与我们在南沙群岛海域得到的结果相一致。结合POC/PTh比值,估算出3个站位从真光层输出的颗粒有机碳(POC)通量分别为4.025.0和5.4mmolC·m-3-d-1。文中进一步讨论了234Th与POC两者停留时间的关系。  相似文献   

4.
A tracer model with random diffusion coupled to the hydrodynamic model for the Zhujiang River Estuary (Pearl River Estuary, PRE) is to examine the effect of circulations on the transport of completely conservative pollutants. It is focused on answering the following questions: (1) What role does the estuarine plume front in the winter play in affecting the pollutants transport and its distribution in the PRE? (2) What effect do the coastal currents driven by the monsoon have on the pollutants transport? The tracer experiment results show that: (1) the pollutant transport paths strongly depend on the circulation structures and plume frontal dynamics of the PRE and coastal waters; (2) during the summer when a southwesterly monsoon prevails, the pollutants from the four easterly river inlets and those from the bottom layer of offshore stations will greatly influence the water quality in Hong Kong waters, however, the pollutants released from the four westerly river-inlets will seldom affect the water quality of Hong Kong waters due to their transport away from Hong Kong; (3) during the winter when a northeasterly monsoon prevails, all pollutants released from the eight river gates will be laterally transported seaward inside the estuary and transport westward in the coastal waters along the river plume frontal zone. However, pollutants released from the surface layer of offshore stations near or east of the Dangan Channel will be carried into the coastal waters of Hong Kong by the landward component of the westward coastal current driven by the winter northeasterly monsoon. But the pollutants from the bottom layer of the offshore stations will be carried away from the offshore by the bottom flow driven by the northeasterly monsoon. This implies that only surface-released matter from offshore stations will affect the water quality of the coastal waters around Hong Kong during the winter when a northeasterly monsoon prevails.  相似文献   

5.
A tracer model with random diffusion coupled to the hydrodynamic model for the Zhujiang River Estuary (Pearl River Estuary, PRE) is to examine the effect of circulations on the transport of completely conservative pollutants. It is focused on answering the following questions: (1) What role does the estuarine plume front in the winter play in affecting the pollutants transport and its distribution in the PRE ? (2) What effect do the coastal currents driven by the monsoon have on the pollutants transport? The tracer experiment results show that: (1) the pollutant transport paths strongly depend on the circulation structures and plume frontal dynamics of the PRE and coastal waters; (2) during the summer when a southwesterly monsoon prevails, the pollutants from the four easterly river inlets and those from the bottom layer of offshore stations will greatly influence the water quality in Hong Kong waters, however, the pollutants released from the four westerly river-inlets will seldom affect the water quality of Hong Kong waters due to their transport away from Hong Kong; (3) during the winter when a northeasterly monsoon prevails, all pollutants released from the eight river gates will be laterally transported seaward inside the estuary and transport westward in the coastal waters along the river plume frontal zone. However, pollutants released from the surface layer of offshore stations near or east of the Dangan Channel will be carried into the coastal waters of Hong Kong by the landward component of the westward coastal current driven by the winter northeasterly monsoon. But the pollutants from the bottom layer of the offshore stations will be carried away from the offshore by the bottom flow driven by the northeasterly monsoon. This implies that only surface-released matter from offshore stations will affect the water quality of the coastal waters around Hong Kong during the winter when a northeasterly monsoon prevails.  相似文献   

6.
1996年 9~10月在厦门湾上屿附近海域定点站连续6个航次测定了水柱中溶解态(DTh)、颗粒态~(234)Th(PTh)和溶解态~238U,获得了~234Th的时空分布图象。研究海域水柱中DTh、PTh和总~234Th(TTh)的放射性比度分别在0.80~3.95山/m~3、1,93~5.65Bq/ m~3和 3.47~9. 18Bq/m~3之间,整个水柱中 DTh、PTh和TTh均与~(238)U呈不平衡,其特征是~(234)Th亏损,且亏损程度明显大于大洋水体。颗粒态~(234)Th和总悬浮颗粒物(TSM)在水体中的分布及其随时间的变化趋势相当一致,非生物过程可能对近岸海域水体中~(234)Th的分布起着非常重要的作用。  相似文献   

7.
Plastic pollution has biological, chemical, and physical effects on marine environments and economic effects on coastal communities. These effects are acute on southeastern Hawai‘i Island, where volunteers remove 16 metric tons of debris annually from a 15 km coastline. Although the majority is foreign-origin, a portion is locally-generated. We used floating debris-retention booms in two urban waterways to measure the input of debris from Hilo, the island’s largest community, and released wooden drifters in nearby coastal waters to track the fate of that debris. In 205 days, 30 kilograms of debris (73.6% plastic) were retained from two watersheds comprising 10.2% of Hilo’s developed land area. Of 851 wooden drifters released offshore of Hilo in four events, 23.3% were recovered locally, 1.4% at distant locations, and 6.5% on other islands. Comparisons with modeled surface currents and wind were mixed, indicating the importance of nearshore and tidal dynamics not included in the model. This study demonstrated that local pollutants can be retained nearby, contribute to the island’s debris-accumulation area, and quickly contaminate other islands.  相似文献   

8.
林以安  Martin  J.M  Thomas  A.J 《海洋与湖沼》1996,27(2):145-150
于1986年1月,采取大体积取样,Co-APDC螯合并沉淀富集分离,银片上自沉积和a-计算分析,研究长江口区可溶态210Pb的来源,分布和逗留时间。结果表明,全区平均放射性比度为7.5dpm/m^3,从河向海纵向分布呈口内段和近外海两端高,而低谷出现在中间的口门外最大浊度及稀释带高生产力区。210Pb明显因悬浮颗粒物的吸附絮凝沉降和浮游生物的吸收利用被清除。经探析,该区210Pb主要来源是大气气溶  相似文献   

9.
《Journal of Sea Research》1999,41(1-2):35-53
Suspended matter samples filtered from surface waters and two depth profiles from the Flores Sea and Makasar Strait were investigated by electron probe X-ray microanalysis (EPXMA) and laser microprobe mass analysis (LAMMA). EPXMA yielded discrete morphological and chemical analysis of the major particle types of suspended matter. Cluster analysis revealed that thirteen main particle types described the composition of suspended matter of the Flores Sea and Makasar Strait. Silicates, aluminosilicates and Fe-oxyhydroxides were the predominant particle types. Suspended matter of the basins studied contained high levels of tin-bearing particles. On the basis of their composition, tin particles can be divided into three groups: (1) tin oxide/hydroxides (cassiterite, romarchite, hydroromarchite); (2) iron-oxyhydroxides with adsorbed tin; and (3) mixed oxidation state tin hydroxysulphates. Only ultra-fine cassiterite particles enter the seawater in suspended state. Dissolved tin species entering the sea have three alternatives: (1) to be scavenged by Fe-oxyhydroxides; (2) to precipitate as tin oxide/hydroxides (romarchite, hydroromarchite); (3) to precipitate as tin hydroxysulphates. The conclusion is that dissolved and suspended tin originate from local sources in the land frame of the basins as well as from remote sources in the Indonesian Archipelago. Four different sectors of the waters studied have suspended matter with different composition: (1) the Mahakam River–Delta zone; (2) the open Flores Sea; (3) the landlocked Saleh Bay; (4) the Makasar Strait proper. The depth distribution of suspended particle types is mainly influenced by: (1) the bottom nepheloid layer and calcite lysocline in the Flores Sea; (2) the high bioproduction in the surface water layer and the vertical distribution of organic matter in the Makasar Strait.  相似文献   

10.
对北太平洋西部海域、苏禄海及印尼海、中国南海、印度洋东部海域、孟加拉湾及安达曼海等表层水体中放射性核素137Cs的活度进行了测定。结果表明,上述海域表层水体中137Cs活度显示了较大的变化范围,最低值出现在南极附近的南大洋(1.1Bqm-3),较高的活度值则出现在北太平洋西部海域及中国南海(3Bqm-3)。在所研究水域范围内,137Cs活度的纬度分布特征并没有完全有效地反映出137Cs的全球理论大气沉降趋势及其纬度效应。综合本研究及Miyake等人(1988)的测定结果,我们计算出137Cs自表层海水中的析出速率在苏禄海及印尼海约为0.016/a,在孟加拉湾及安达曼海约为0.033/a,在中国南海约为0.029/a,这一结果明显低于西北太平洋日本沿海表层水体中137Cs的析出速率。这可能是因为在这些海域,横向及纵向的水体混合过程相对都较慢,而且颗粒物对137Cs的吸附析出过程也比较弱所致。  相似文献   

11.
《Marine Chemistry》1987,21(1):75-89
The distribution of hydrocarbons in the water column seems to be affected by inputs from both interfaces of accumulation: the surface microlayer and the water/sediment interface. Volatilization and accommodation appear to be the major factors controlling the fate of hydrocarbons, especially in the dissolved phase, whereas some classes of particles are confirmed as important supports for the transport of such pollutants. In this respect, the 20–200 μm planktonic fraction is less contaminated than the total suspended matter.This study gives evidence for intense bacterial degradation affecting the hydrocarbons in the whole water column. In spite of the chronic petroleum pollution, we have also observed the predominance of n-alkanes in the [n-C16; n-C18] and [n-C27, n-C29] boiling ranges, which could be used as biological markers in these highly polluted waters.  相似文献   

12.
Three-dimensional numerical simulation for transport of oil spills in seas   总被引:4,自引:0,他引:4  
This study extends previous two-dimensional research [Wang, S.D., Shen, Y.M., Zheng, Y.H., 2005. Two-dimensional numerical simulation for transport and fate of oil spills in seas. Ocean Engineering 32, 1556–1571] to three dimensions in order to investigate the vertical dispersion/motion of the spilled oil slick, which is a more realistic model of the motion of the spilled oil. To this end, a three-dimensional (3-D) model, based on the particle approach, is developed for simulating oil spill transport and fate in seas. The amount of oil released at sea is distributed among a large number of particles tracked individually. These particles are driven by a combination of water current, wave- and wind-induced speed and move in a 3-D space. Horizontal and vertical diffusion are taken into account using a random walk technique. The model simulates the most significant processes which affect the motion of oil particles, such as advection, surface spreading, evaporation, dissolution, emulsification, turbulent diffusion, the interaction of the oil particles with the shoreline, sedimentation and the temporal variations of oil viscosity, density and surface tension. In addition, the processes of hydrolysis, photo-oxidation and biodegradation are also considered in this model. The model has been applied to simulate the oil spill accident in the Bohai Sea.  相似文献   

13.
海南岛三亚港现代沉积速率的研究   总被引:8,自引:0,他引:8  
对1988年所采集的海南岛三亚港6个沉积柱样作了沉积结构及^210Pb放射性分析。结果表明,三亚港潮汐通道及航道上,沉积物主要为细颗粒的粉砂、粘土,沉积速率为0.91-1.24cm/a,近年来砂质物的输入,反映了疏浚等人类活动对该区的影响;外港浅滩砂洲区的沉积速率小于0.4cm/a;潮汐通道中过剩^210Pb总量亦明显大于港口的其它区域。  相似文献   

14.
n-Alkanes and polyaromatic hydrocarbons (PAHs) were analysed on suspended particles from surface waters of the Changjiang Estuary to assess the sources and fate of river-borne material in a meso-tidal riverine system. The n -alkane and PAH assemblages indicated prevailing terrestrial and anthropogenic inputs. Measurements performed at several stations within the estuary showed lower concentrations in the North than in the South Channel. These observations were in agreement with the dynamics and flow pattern of the Changjiang in this part of the estuary. Concentrations measured at a tidal series station over two tidal cycles exhibited a significant increase in flooding of more saline waters. Total suspended particles were also higher, reaching their maximum value (1·9 g l-1) at high tide during the first flood. These findings were attributed to the landwards transport of the turbidity maximum zone from the outer estuary, as the Taiwan Warm Current funnels into the Changjiang River mouth. Saltier and less turbid waters with a more pronounced marine character could reach the tidal series site at the final stage of the second flood. During the ebb, suspended n-alkane and PAH concentrations were lower but their compositional features remained similar to those during the flood. A high total suspended particle concentration was observed during the ebb, presumably due to the Huang Pu waters flushing. The n -alkane and PAH content of the particles during such an event pointed out stronger contamination of the waters after crossing the highly populated and industrialized area of Shanghai. Flux calculations based on current meter data indicated significant differences between flood and ebb transports.  相似文献   

15.
本文提出一种将二维动态水质模型与三维稳态水质模型有机结合的新方法,用来处理沿海深水岸段排污口近区污染物混合问题,使之能较好地再现其客观混合过程。将这种方法应用于深圳大鹏湾某大型石化项目的环境影响预测中.结果令人满意。  相似文献   

16.
Measurements of phytoplankton distribution and production, and zooplankton abundance and biomass were made during the summer of 1979 along several shelf-slope transects in the Mid-Atlantic Bight. At the shelf-break, macrozooplankton (>200 μm) grazing was estimated to be sufficient to remove a substantial proportion of daily phytoplankton production. In contrast, on the shelf and in slope waters, where ciliates were abundant, estimates of macrozooplankton grazing indicated a consumption rate less than 15% of the daily primary production. Ciliate grazing, even at non-maximum rates, potentially could have consumed the entire daily primary production in all areas sampled. The findings indicate that the nature of the heterotrophic community is spatially variable in offshore waters even during summer conditions and could influence not only trophodynamic pathways but perhaps nutrient regeneration and recycling. This would be an important consideration in evaluating the fate of particle-bound chemcial species in the water column since fecal pellet producing zooplankton would affect rates of removal and sedimentation in a different manner than ciliates which produce non-compacted digestive debris.  相似文献   

17.
A novel approach to particle sizing in estuarine waters using a submersible laser diffraction instrument is described. In situ measurements with this instrument are rapid and avoid both the physical disruption of fragile aggregates with pumping and the settlement of larger particles in isolated samples which interfere with currently available sizing techniques. Measurements of the size distributions of suspended particle populations in the Tamar Estuary using this apparatus are compared with measurements carried out on discrete samples obtained from the same depth by pumping. The results confirm the fragile nature of estuarine aggregates and the necessity for in situ measurements in studies of estuarine suspended particle dynamics and fluxes.  相似文献   

18.
阐述了大亚湾北部沿岸污水排海位置优选的方法。根据研究海区的水深条件、海岸地形特点、欧拉余流流场、海流流速、渔业水产、旅游等资源的分布特征和水质条件等,定性地确定6个预选排污海区。然后利用Roberts的近区初始稀释模型和二维水质模型,以南海石油化工项目的污水排海为例,定量地计算被确定的六个预选排污海区的稀释扩散输移能力。通过比较,认为大亚湾北部沿岸的污水不适宜就近排入靠岸海域。当污水量不大时,排污位置选在距马鞭洲岛南端以东约4km处(即C海区),可达到环境、经济、社会三大效益协调统一的效果。但当污水量较大,排海污染物量大时,排污海域的位置应选择在赤洲岛与黄毛山岛之间,即E海区.或在C海区与E海区之间。  相似文献   

19.
Aluminium distributions in Central East Atlantic waters (Canary Islands)   总被引:1,自引:0,他引:1  
DASA-reactive aluminium and nutrients have been determined on a grid located in Central East Atlantic waters (Canary Islands) during early spring. The sample area shows major features of biogeochemical interest, such as elevated aeolian (dust) inputs from the Sahara desert, proximity to upwelling areas (150–200 km) and mesoscale features induced by the effect of the islands on the course of the Canary Current. The aluminium distributions show a marked latitudinal E-W gradient. The low values towards the east are explained by the intrusion of cold waters originated in the upwelling region off northwest Africa, where aluminium is scavenged by organic matter. High values towards the west suggest aeolian inputs that may stretch to below the seasonal thermocline. Nutrients are shown to be inefficient to trace these features, as they are quickly used by biological uptake. The mesoscale circulation south of the islands produces cyclonic and anticyclonic eddies that, respectively, rise and sink the thermocline over 60 m. Aluminium appears to be a useful tracer for this mixing process as well as for the intrusion of cold waters coming from the eastern boundary.  相似文献   

20.
1994 年9 月1 日~11 日采集珠江口表层海水水样。利用模拟水样和现场水样稀释比与化学要素浓度关系的数学模式,对珠江口表层水Alk ,K+ ,Na+ ,Ca2 + 在运移过程的稀释规律进行了研究,并利用上述模式计算了珠江口表层水样的Alk ,K+ ,Na+ ,Ca2 + 在河海水整个混合过程和相应于各稀释比条件下的转移量。  相似文献   

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