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笔者于2012年8月对乐清湾表层沉积物进行了采集,并测定了其中各重金属(汞、砷、铅、镉、铜、铬和锌)元素的含量。采用地累积指数法和潜在生态风险指数法对重金属污染情况进行了评价,结果表明:7种重金属元素的地累积污染指数由大到小依次排列为:铜、锌、汞、镉、砷、铅、铬,乐清湾海域基本上所有站位均处于"无-中"的污染水平;同时该海域沉积物重金属污染总体潜在生态风险程度低,各重金属元素潜在生态风险程度由高到低依次排列为:镉、砷、铜、汞、铅、锌、铬,其中镉为该海域主要潜在生态风险因子。 相似文献
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胶州湾、莱州湾潮间带沉积物污染比较 总被引：4，自引：0，他引：4
系统地在胶州湾、莱州湾潮间带获取表层沉积物样,对沉积物中有机污染（有机质,石油类）、重金属（汞,铜,铅,锌,镉,铬,砷）、营养盐（总磷,总氮,总碳）、硫化物进行了定量测定。分析结果表明：除镉、总磷外,各物质在胶州湾潮间带的质量分数普遍大于在莱州湾潮间带内的质量分数;Q型聚类分析将两湾分成两类,受到工业排污、生活污水等人为因素影响严重的胶州湾东部为一类,而受人为因素影响较小的胶州湾西部和莱州湾等其余站位为一类;胶州湾潮间带生态危害程度要高于莱州湾潮间带。 相似文献
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珠江口及其邻近海域重金属的河口过程和沉积物污染风险评价 总被引：3，自引：0，他引：3
根据2006年到2007年,“908专项”珠江口附近海域海水与沉积物的调查资料,研究珠江口海域海水和沉积物中重金属含量分布特征;珠江口及附近海域海水中铜、铅、锌、镉、总铬、汞、砷的含量平均值均符合国家一类海水水质标准,采用数理统计相关分析计算出各重金属元素与各环境因子之间的相关,发现在河口重金属主要以稀释混合过程为主,悬浮颗粒物中重金属在酸化作用下以解吸作用为主,氧化还原作用的影响不大.沉积物中铜-锌、铅-锌、铜-镉、铅-镉、锌-镉、铅-铬,锌-铬、镉-铬8组元素间具有显著的相关性,表明它们具有相似的元素地球化学性质和来源;并运用Hakanson潜在生态危害系数法对其潜在生态危害程度进行评估,珠江口沉积物的潜在生态风险的来源是镉和汞占据主要权重,尤其珠江口沉积物中镉的污染程度和潜在生态风险局部激增的特点值得重点关注. 相似文献
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《中国海洋大学学报(自然科学版)》2020,(Z1)
本文通过整编2000—2016年长江流域沉积物重金属研究数据,对7种重金属(铜、汞、铅、锌、镉、铬和砷)的含量、空间分布和赋存形态比例进行分析总结,并对其污染风险进行评价。研究结果发现沉积物中镉(Cd)含量超标最严重;从污染风险看,Cd在沉积物中的累积程度和生态风险要远高于另外6种重金属;从赋存形态看,Cd在沉积物中以酸提取态(B1)为主,生物可利用性要高于另外6种重金属,易在环境中迁移转化。本文结果表明Cd是长江流域沉积物的首要重金属污染元素和优控重金属元素。优先关注并重点防控沉积物Cd污染对控制长江流域重金属污染存在积极作用。 相似文献
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海洋生物体中痕量金属分析方法的实验室间分析互校 总被引：3，自引：0，他引：3
本文介绍了我国首次海洋生物体中痕量金属分析方法的实验室间互校结果。38个实验室分别参加了铜、铅、锌、镉、铬、硒、砷和汞8种元素,共22个分析方法的分析互校。互校结果表明,除了铅的分光光度法外,其余21个分析方法均能获得准确可比的分析结果。 相似文献
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浙江沿海贝类体内重金属元素含量水平与评价 总被引：4，自引：0，他引：4
利用2006年秋季在浙江沿海潮间带采集的27个典型的双壳纲、腹足纲和头足纲类软体动物(贝类)样品,分析检测了其肌肉组织中锌、铜、镉、砷、铬、铅和汞重金属元素的含量,结果表明:(1)不同重金属元素在不同种类贝类肌肉组织中的含量是不同的,铜、锌元素的含量相对最高,铅、镉、铬和砷元素的含量次之,汞元素的含量最低;重金属元素在贝类体内吸收过程中可能存在拮抗作用,铅、铬、砷与铜、锌元素含量负相关性显著。(2)双壳纲贝类对重金属元素的生物累积最明显,其作为海洋环境监测的指标生物具有明显优势。(3)生物体质量评价表明,铜、锌元素在贝类体内的富集明显,具有潜在的生物累积危害,其他重金属元素在贝类体内的累积均没有超过"潜在危害"的阈值;牡蛎体内铜、锌元素的含量超过海洋生物Ⅲ级质量标准,并超过无公害水产品中有毒有害物质限量标准,但是并没有明显的污染现象,其余贝类生物质量(重金属元素含量)状况基本良好。 相似文献
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渤海莱州湾表层沉积物中金属元素分布及环境质量 总被引：3，自引：1，他引：2
利用X-射线荧光光谱仪、等离子质谱仪或原子荧光光度计测定了莱州湾表层沉积物中金属元素的含量,探讨了它们的分布特征、来源及污染程度,结果表明,沉积物中铜、锌、铅、镉、砷、镍、铬、钴、钒、钪、铁、锰的含量由近岸向湾内递减,莱州湾北部海域的含量大于南部的。银含量高的沉积物主要分布在莱州湾中部偏西南的环流中心区。沉积物中砷和镍含量超过ERL值,潜在生态风险较高。富集系数和主成分分析显示,沉积物中铁、铜、锌、镉、砷、铬、镍、钴、锰、钒和钪为无富集,砷为轻度富集,铅和银为中度富集。铁、铜、锌、镉、铬、镍、钴、锰、钒、砷和钪主要来源于自然源,铅既有岩石和土壤风化产物硅酸盐矿物等自然源的贡献,又受到了人为活动的影响,银主要受人为活动的影响。聚类分析表明,可把莱州湾沉积物分为4类,其中黄河口西北缘沉积物中砷和镍污染生态风险最高,其次是莱州湾中部和北部。 相似文献
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北部湾沉积物中重金属元素的地球化学特征及物源初探 总被引：5，自引：1，他引：5
本文根据北部湾沉积物岩心样调查结果计算了铜、铅、锌、镉、汞、砷等重金属元素的背景值,并分析了其与南海陆架区和南海全海域沉积物背景值、广西土壤背景值之间的差异.对北部湾表层沉积物中重金属含量及近10 a的变化趋势以及岩心样中重金属元素含量近百年以来的变化趋势综合分析结果表明:北部湾近岸海域沉积物中铜、砷、汞、镉重金属元素含量总体呈增长趋势,北部湾中部海域沉积物中重金属元素含量的年际变化有升有降,至湾口处沉积物中重金属元素的含量基本不变.综合评价结果表明,北部湾近岸沉积物中砷、汞、镉等重金属元素的地球化学特征明显受到广西人类活动的影响.北部湾沉积物中的重金属元素主要来源于人类活动影响下的广西沿岸陆源输入,经由琼州海峡的外部海域物质输入也有贡献. 相似文献
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Chandralata Raghukumar G. Sheelu P. A. Loka Bharathi Shanta Nair C. Mohandass 《Marine Georesources & Geotechnology》2001,19(1):1-16
In order to assess the impact of deep-sea mining on the in situ benthic life, we measured the microbial standing stock and concentration of organic nutrients in the deep-sea sediments of the Central Indian Ocean Basin in the Indian pioneer area. Sediments were collected using box core and grab samples during September 1996. The total bacterial numbers ranged from 10 10 -10 11 cells per g -1 dry weight sediment. There was a marginal decrease in the number of bacteria from surface to 30 cm depth, though the subsurface section registered a higher number than did the surface. The highest numbers were encountered at depths of 4-8 cm. The retrievable number of bacteria were two orders less in comparison with the direct total counts of bacteria. An almost homogeneous distribution of bacteria, total organic carbon, living biomass, and lipids throughout the depth of cores indicates active microbial and benthic processes in the deep sea sediments. On the other hand, a uniform distribution of total counts of bacteria, carbohydrates, and total organic carbon in all the cores indicates their stable nature and suggests that they can serve as useful parameters for long-term monitoring of the area after the benthic disturbance. Further studies on temporal variability in this region would not only verify the observed norms of distribution of these variables but would also help to understand restabilization processes after the simulated benthic disturbance. 相似文献
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海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明：土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。 相似文献
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Geoacoustic Inversion via Genetic Algorithm and Its Application to Manganese Sediment Identification
An acoustic inversion method using a wide-band signal and two near field receivers is proposed and applied to multiple layered seabed models including a manganese sediment. The inversion problem can be formulated into a probabilistic model comprised of signals, a forward model, and additive noise. The forward model simulates wide-band signals, such as chirp signals, and is chosen to be the source-waveletconvolution plane wave modeling method. The wavelet matching technique, using weighted least-squares fitting, estimates the sediment sound-speed and thickness on which determination of the possible numerical ranges for a priori uniform distribution is based. The genetic algorithm is applied to a global optimization problem to find a maximum a posteriori solution for determined a priori search space. Here the object function is defined by an L 2 norm of the difference between measured and modeled signals. Not only the marginal pdf but also its statistics are calculated by numerical evaluation of integrals using the samples selected during importance sampling process of the genetic algorithm. 相似文献
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Derek V. Ellis 《Marine Georesources & Geotechnology》2001,19(1):51-63
This article reviews information recently available from existing marine and coastal mining for responses to environmental issues affecting marine mining at different depths. It is particularly but not exclusively concerned with those issues affecting seabed biodiversity impact and recovery. Much information has been gathered in the past 10 years from shallow mining operations for construction aggregate, diamonds, and gold, from coastal mines discharging tailings to shallow and deep water, and from experimental deep mining tests. The responses to issues identified are summarized in a series of eight tables intended to facilitate site-specific consideration. Since impacts can spread widely in the surface mixing layer SML, and can affect the biologically productive euphotic zone, the main issues considered arise from the depth of mining relative to the SML of the sea. Where mining is below the SML, the issue is whether it is environmentally better to bring the extraction products to the surface vessel for processing (and waste discharge), or to process the extraction products as much as possible on the seabed. Responses to the issues need to be sitespecific, and dependent on adequate preoperational environmental impact and recovery prediction. For deep tailings disposal from a surface vessel, there are four important environmental unknowns: (1) the possible growth of "marine snow" (bacterial flocs) utilizing the enormous quantities of fine tailings particles (hundreds or thousands of metric tons per day) as nuclei for growth, (2) the possibility that local keystone plankton and nekton species may migrate diurnally down to and beyond the depth of deep discharge and hence be subjected to tailings impact at depth, (3) the burrow-up capability of deep benthos and their ability to survive high rates of tailings deposition, and (4) the pattern and rate of dispersion of a tailings density current through the deep water column from discharge point to seabed. Actions to obtain relevant information in general and site-specifically are suggested. 相似文献
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G. Parthiban 《Marine Georesources & Geotechnology》2000,18(3):223-235
Particle fluxes were measured 7 m above the sea bottom during the predisturbance, disturbance, and postdisturbance periods by using time series sediment traps attached to seven deep-sea moorings deployed in the INDEX experiment site in the Central Indian Basin. The predisturbance particle fluxes varied between 22.3 to 55.1 mg m -2 day -1 . Increased and variable particle fluxes were recorded by the sediment traps during the disturbance period. The increase observed was 0.5 to 4 times more than the background predisturbance fluxes. The increases in particle fluxes (~4 times) recorded by the sediment trap located in the southwestern direction (DMS-1) were the greatest, which could be the result of preferential movement of resuspended particles generated during the deep-sea benthic disturbance along the general current direction prevailing in this area during the experimental period. Also, the traps located closer to the disturbance area recorded greater fluxes than did the traps far away, across the Deep Sea Sediment Resuspension System path. This variability in recorded particle fluxes by the traps around the disturbance area clearly indicates that physical characteristics such as grain size and density of the resuspended particles produced during the disturbance had an important effect on particle movement. The postdisturbance measurements during ~5 days showed a reduction in particle fluxes of ~50%, indicating rapid particle settlement. 相似文献
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The advanced piston corer (APC) has been used by the Ocean Drilling Program since 1985 for recovering soft sediments from the ocean floor. The pullout force measured on extracting the core barrel from the sediment is shown to correlate with the average shear strength of the sediment core measured in the ship's laboratory. A simple rule of thumb is derived relating the shear strength of the sediment to the pullout force. Multiple APC holes at individual sites allow the consistency of the pullout measurements to be assessed. The effects of different operational procedures during APC coring are also explored. Although generally applicable, the correlation between pullout force and laboratory measurements of shear strength breaks down for some APC holes, possibly because of the disturbance of some sediment types during the APC coring process. A better understanding of the physical process of APC coring, and its effect on the properties of the sediment both inside and immediately outside the core barrel, would indicate what confidence can be put on the measurement of pullout force as a way of evaluating the in situ shear strength of deep sea sediments. 相似文献
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Oedometer tests have been carried out on 70 undisturbed surficial clays (at approximately 250 mm below the mudline), mostly collected by free-fall corers from sites widely scattered throughout the deep-sea North Atlantic. Acoustic measurements were also made, initially on contiguous samples and ultimately on the same sample using a geophysically instrumented oedometer which also collected electrical resistivity data. Apart from those quiescent areas below the carbonate compensation depth, such as north of the West Indies where very fine clays exist, most of the samples are silty clays whose geotechnical-geophysical properties are dependent on the type of clay minerals present (and their ability to take in moisture), the sand-size fraction, and the quantity of carbonate present. Thus the pure clays have high compressibilities which decrease on the addition of coarse particles, while the converse is true for the acoustic parameters, these increasing with the sand fraction. Using the notion of the intrinsic compression line for all samples, and comparison to it of the measured compression curves, it is clear that, contrary to some previously held ideas, most deep-sea clays are normally consolidated; the addition of carbonate has the effect of creating an open, stronger sediment skeleton. Interestingly, where information is available, the variation with depth of a sample's acoustic velocity follows the void ratio pressure relationship of the compression curve. This allows the construction of an in-situ sediment compression curve using the in-situ geophysical observations. 相似文献
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Phylogenetic diversity and phenotypic characterization of cultivable bacterioplankton isolated from polar oceans 总被引：1，自引：0，他引：1
A set of 27 marine planktonic bacteria isolated from the polar regions was characterized by 16S rDNA sequencing and physiological and biochemical testing. More than half of these bacteria were positive for caseinase, gelatinase and 13-glucosidase, and could utilize glucose, maltose or malic acid as carbon source for cell growth. Twelve isolates expressed nitrate reduction activities. Except for one antarctic isolate BSwlO175 belonging to Actinobacteria phylum, these isolates were classified as γ-Proteobacteria, suggesting that γ-Proteobacteria dominated in cultivable marine bacterioplankton at both poles. Genus Pseudoalteromonas was the predominant group in the Chukchi Sea and the Bering Sea, and genus ShewaneUa dominated in cultivable bacterioplankton in the Prydz Bay. With sequence similarities above 97%, genus Psychrobacter was found at both poles. These 27 isolates were psychrotolerant, and significant 16S rDNA sequence similarities were found not only between arctic and antarctic marine bacteria （ 〉 99% ）, but also between polar marine bacteria and bacteria from other aquatic environments （ ≥ 98.8% ）, including temperate ocean, deep sea, pond and lake, suggesting that in the polar oceans less temperature-sensitive bacteria may be cosmopolitan and have a bipolar, even global, distribution at the species level. 相似文献