桑沟湾经济贝类有机氯农药和多氯联苯残留水平及分布特征

采用气相色谱法定量测定了桑沟湾海域2009年4月-2009年12月的经济贝类中有机氯农药和多氯联苯的残留量。结果显示：该海域贝类中 HCHs 为 N.D.~2.04×10-9,均值为0.30×10-9; DDTs 为(0.13~3.36)×10-9,均值为0.97×10-9;PCBs为(0.01~3.20)×10-9,均值为0.59×10-9,有机氯物质含量均低于相关国家标准值,符合食用安全要求。经济贝类中的有机氯农药的组分特征为HCHs中b-HCH占优势, DDTs中p, p′-DDT占相对优势; PCBs中多为5~7个氯原子。与北海等6个海域相比,桑沟湾海域经济贝类有机氯污染物中, HCHs、DDTs和PCBs的残留量都处于中等水平。     

浙江沿岸海域经济贝类中有机氯农药和多氯联苯的残留分布与污染评价

对2006年6月和2007年6月采集于浙江沿岸海域12个站位的5种经济贝类样品,采用气相色谱(GC)方法,进行了有机氯农药(HCHs和DDTs)和多氯联苯(PCBs)残留量的检测,分析了不同种类贝类中HCHs、DDTs和PCBs异构体组分特征,探讨了浙江沿岸海域HCHs、DDTs和PCBs残留分布状况、年际变化趋势和DDTs的来源,并与厦门岛东部等5个主要沿海海域进行了污染物残留量的比较。结果表明:(1)调查区各海域贝类中的HCHs、DDTs和PCBs残留量(湿质量)分别为:(ND~7.86)×10-9,(0.72~281.73)×10-9,(ND~97.95)×10-9;残留量(湿质量)平均值分别为:1.50×10-9,33.65×10-9,19.56×10-9。调查区各海域所有贝类中的HCHs残留量,均符合国家一类生物质量标准,DDTs残留量仅在四角蛤蜊中符合国家一类生物质量标准,在其余4种贝类中仅符合国家二类生物质量标准。DDTs残留量平均值明显高于HCHs和PCBs,因此可以将DDTs视为调查区各海域典型的有机氯污染物。(2)在HCHs和DDTs组分中,分别以-αHCH和P,P-′DDT占优势;在PCBs中,以含4~7个氯原子的PCB占主要优势,调查区部分海域有新的HCHs和DDTs污染源。(3)自2006年6月至2007年6月,HCHs和PCBs残留量总体呈下降趋势,而DDTs残留量则呈上升趋势,不同海域的有机氯残留量有较明显差异。DDTs的污染源与农业生产中三氯杀螨醇的使用有关。(4)与厦门岛东部等5个主要沿海地区相比,浙江沿岸海域经济贝类有机氯污染物中,HCHs残留量仍处于较低水平,DDTs残留量处于中等水平,PCBs残留量则处于较高水平。     

福建省漳江口表层沉积物中滴滴涕的残留特征

采用GC-ECD方法分析了漳江口表层沉积物样品中滴滴涕（DDTs）的残留量,并对其来源和生态风险进行了分析与评价。结果表明,沉积物中DDTs的残留量平均为16.4 ng·g^-1,其4种异构体p,p′-DDE,p,p′-DDD,o,p′-DDT,p,p′-DDT的平均残留量分别是4.12ng·g^-1,9.54 ng·g^-1,0.529 ng·g^-1和2.26 ng·g^-1。DDTs沿漳江呈波浪型分布,至佳洲岛分流前DDTs的残留比较高。组成特征显示DDTs主要为环境中的早期残留,且多为厌氧性生物降解,而在Z9站（江心岛后）近期可能有新的DDTs输入。与其它地区相比,漳江口表层沉积物中的DDTs残留属于中等水平。生态风险评价结果显示,86.7%的样品DDTs含量超过风险评估低值（ERL）,13.3%样品的含量超过风险评估中值（ERM）,说明存在较高的生态风险,对生态环境已造成一定的危害,必须引起重视。     

厦门港湾表层沉积物BHC和DDT含量的分布

人工合成的有机氯农药BHC、DDT主要通过大气传输、河口径流和沿岸排水进入海洋。由于海洋生物对它们有较强的富集能力,所以输入到海洋的有机氯农药不但污染海洋环境,而且会通过食物链的传输反馈给人类,危害人类健康。因此,BHC和DDT含量已成为评价环境污染的重要指标。测定表层沉积物中BHC和DDT的含量还可以估计上复水层农药的污染现状,预测生物和非生物因素对污染物分布的影响。本文据1982年9月的调查资料,首次报道了厦门港湾表层沉积物BHC和DDT的含量及其分布特征;初步讨论了岸畔农药使用、水动力、地质地貌和滩涂养殖等因素对BHC、DDT含量分布的影响。     

渤海湾的有机氯农药和多氯联苯

有机氯农药(DDT，BHC)和多氯联苯(PCBs)是人工合成的有机氯化合物。它们的化学性质稳定，在环境中能持久地残留并不易受环境中各种因素的作用而降解，它们在生物体内的累积和生物链中的浓缩已构成对人类和生态系统的潜在危害，早已引起世界各国的关注，并公认为全球性的环境污染物。许多国家的学者对不同海区、各大洋海水、沿岸海水、沉积物以及海洋生物体内的DDT, BHC, PCBs作了广泛深入的调查研究(Elear, 1976; Edwand et al, 1975; Ehrhardt, 1981; Harvey, 1973; Osterroht, 1977;Robert, 1976)。我国对近海海域有机氯农药污染状况作过一些调查，但对多氯联苯未见有过报道。、1980年8月作者在渤海湾采集了26个站位的海水样品，22个站位的沉积物样品和8个毛蚶(Arasubcrenata Lischke)样品，分析了其中DDT, BHC, PCBs的含量水平，并对其在渤海湾中的分布特征作了初步探讨。     

胶州湾水域有机农药HCH的分布和残留量

根据1984年7月、8月和10月的胶州湾水域调查资料,对有机农药HCH在胶州湾水域的分布、来源和季节变化进行了分析,研究结果表明,胶州湾水域没有受到HCH污染。通过7月,HCH含量变化的水平分布,发现土壤中残留的HCH通过地表径流方式汇入近岸水域,并且HCH的含量很低,HCH来源是面来源。通过10月,HCH含量变化的水平分布,发现胶州湾水域输入的HCH只有通过外海的海流输送。HCH含量的季节变化展示了:HCH含量在7月比较高,在10月比较低。这揭示了在7月,HCH的表层含量高,通过沉降,在10月,HCH的表层含量变低。7月和10月,胶州湾水域水体中表层以及胶州湾的湾口水域水体中表、底层HCH含量水平分布表明:表层的HCH的含量减少完全依赖胶州湾潮流的稀释。在禁止HCH农药的使用后,海水中HCH含量大幅减少,这表明陆地残留量的衰减引起水域HCH的减少。而且,海水中HCH含量的快速下降,说明陆地HCH残留量的衰减也较快,下降了38.14%~212.17%。     

大亚湾海域典型有机氯农药生物累积特征及变化因素研究

于2003年采集大亚湾海域28个鱼类等生物样品和14个表层沉积物样品,分析其中滴滴涕(DDTs)、六六六(HCHs)和氯丹(CHLs)各组分的含量以及脂含量和δ15N,δ13C同位素值,重点研究了大亚湾沉积物和生物体中有机氯农药(OCPs)的污染现状及其生物积累规律.大亚湾海域鱼类DDTs,HCHs和CHLs平均含量分别为57.1±52.9,0.30±0.18和0.87±0.35ng/g(湿重);与其他海区相比,该海域生物体中DDTs的含量相对较高,HCHs和CHLs较低;表层沉积物中高的p,p'-DDT含量及较低的(DDE+DDD)/DDT比值(平均为0.56,<1),均显示仍有新的DDTs源输入;OCPs在生物累积中表现出脂溶性的特征,生物体内脂含量越高,其OCPs含量也越高;δ15N,δ13C同位素的研究结果显示肉食性生物比植食性生物更易累积OCPs;大亚湾海域OCPs的生物-沉积物累积系数(BSAF)与有机物的亲脂性程度即辛醇-水比值(K_OW)存在显著的正相关.     

胶州湾水域有机农药HCH的分布和稀释过程

根据1983年5月、9月和10月的胶州湾水域调查资料,分析了有机农药六六六(HCH)在胶州湾水域的分布、来源和季节变化。研究结果表明:在胶州湾水域没有受到HCH的污染。通过河流输入近岸水域和通过地表径流直接输入近岸水域的HCH含量是一样的,非常低。HCH来源是面来源。在夏季,输入的胶州湾水域的HCH含量与春、秋季相比,相对较高。根据HCH在胶州湾水域的分布、来源和季节变化,认为1983年HCH含量变化由胶州湾附近盆地的雨量大小所决定。在胶州湾湾口水域,表层的HCH水平分布状况与底层的HCH水平分布状况一致。HCH的含量在表层的减少完全依赖胶州湾潮流的稀释,不仅在水体表层中HCH含量会形成低值区域,而且在水体底层中HCH含量也会形成低值区域。     

黄河三角洲表层土壤有机氯农药分布及生态风险评价

利用GC-MS测定37个黄河三角洲表层土壤样品中的有机氯农药含量,揭示其中的有机氯农药残留特征,结果表明,HCHs的含量为0.04～1.19 ng/g,均值为0.47ng/g,DDTs的含量为0.05～6 ng/g,均值为0.85 ng/g.多数站位β-HCH、DDE百分含量较高,表明可能来自土壤中农药残留,仅2个站位DDT/(DDE+DDD)＞1,可能有新的农药输入.生态风险评价结果表明,该区有机氯污染的生态风险较低.     

桑沟湾水体中有机氯农药和多氯联苯的浓度水平及分布特征

以气相色谱-电子捕获检测器(GC/ECD)分析并结合外标法,定量测定了桑沟湾海域水体中15种有机氯农药和多氯联苯类化合物的含量.结果表明:桑沟湾海域表层水体中有机氯农药浓度范围为20.34～52.86 ng/L,底层水中的浓度范围为31.7～58.68 ng/L.该海域水体中共检出有机氯农药6种,DDTs类化合物是水体...     

Microbial Biomass and Organic Nutrients in the Deep-Sea Sediments of the Central Indian Ocean Basin

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.     

海上大直径钢管桩打桩过程中桩周土强度弱化研究

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。     

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.     

Phylogenetic diversity and phenotypic characterization of cultivable bacterioplankton isolated from polar oceans

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.     

Deep-Sea Sediment Compression Curves: Some Controlling Factors, Spurious Overconsolidation, Predictions, and Geophysical Reproduction

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.     

INFORMATION FOR AUTHORS

<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology,     

Evaluation of the Risk of Marine Slope Instability: A Pseudo-3D Approach for Application to Large Areas

This article presents a methodology developed to evaluate the instability of submarine slopes that extend over a large area. Special attention was paid to (1) the complex geometry (bathymetry) and the expanse of the slope, (2) the heterogeneity of the sediment, and (3) the distribution of the pore pressure. The safety factor was considered as a spatially varying quantity. The General Formulation (GLE, Fredlund and Krahn 1977), which fully satisfies equilibrium conditions, was used for evaluating the stability of the marine slope. The submarine slope failure, which occurred on 16 October 1979 during the construction of the new Nice airport, was studied in order to test the developed model. Geotechnical parameters were taken from experimental tests carried out by IFREMER on 19 cores extracted at different depths (from 27 m to 1300 m) (Cochonat, Bourillet, and Savoye, 1993; Mulder et al., 1994). Many scenarios were proposed in order to explain the cause of the Nice slope failure (Habib, 1994). In this article, two of those scenarios were tested. Simulation results are presented and discussed.