Factors affecting the elimination of PCBs in the marine copepod Acartia tonsa     

George B. McManus  Kevin D. Wyman  William T. Peterson  Charles F. Wurster 《Estuarine, Coastal and Shelf Science》1983,17(4):421-430

The effects of feeding, egg laying, and fecal pellet production on the elimination of polychlorinated biphenyls (PCBs) from the marine copepod Acartia tonsa were studied in a series of experiments. Copepods were exposed to ¹⁴C-labelled Aroclor 1254 and allowed to depurate in clean seawater. Copepods fed during depuration eliminated PCBs more rapidly than unfed copepods whether or not the original PCB exposure medium had contained food. Both eggs and fecal pellets contained PCBs during depuration, with the weight specific concentration of PCB in the eggs (up to 407 ppm, dry weight) exceeding four times that in the females that produced them. Female copepods eliminated PCBs twice as rapidly as males, indicating that egg production is an important route for PCB elimination.  相似文献   

Kinetics of phosphate adsorption by iron oxyhydroxides in aqueous systems     

S.A. Crosby  G.E. Millward  E.I. Butler  D.R. Turner  M. Whitfield 《Estuarine, Coastal and Shelf Science》1984,19(2):257-270

The rate of uptake of phosphate onto synthetic Fe(III)- and Fe(II)-derived oxyhydroxides has been studied using reaction conditions similar to those encountered in natural waters. Kinetic analyses were carried out on the adsorption profiles and both first-order and second-order conditional rate constants were obtained. The temperature dependence of some of the rate constants was investigated and corresponding apparent activation energies calculated. Similar experiments and analyses were undertaken using Fe from natural sources and in general the conditional rate constants obtained in seawater were in agreement with the synthetic ones. The results of this study are of value when comparing the time scales of adsorption processes in natural waters with the time scales of mixing and advection.  相似文献   

Organochlorines and dioxin-like compounds in green-lipped mussels Perna viridis from Hong Kong mariculture zones     

So MK  Zhang X  Giesy JP  Fung CN  Fong HW  Zheng J  Kramer MJ  Yoo H  Lam PK 《Marine pollution bulletin》2005,51(8-12):677-687

Concentrations of persistent organic pollutants including polychlorinated biphenyls (PCBs), organochlorine (OC) pesticides and dioxin-like compounds were measured in green-lipped mussels, Perna viridis, collected from seven mariculture zones in Hong Kong between September and October in 2002 in order to evaluate the status, spatial distribution and potential sources of pollution in these areas. Concentrations ranged from 300 to 4400 ng/g lipid weight for total OCs and 170–1000 ng/g lipid weight for total PCBs (based on 28 congeners). Relatively smaller DDT concentrations in mussels compared with previous studies suggest reduced discharges of DDTs from nearby regions into Hong Kong waters. Detection of a mixture of HCH isomers in the mussels indicated that Hong Kong waters were predominantly contaminated by technical HCHs rather than lindane. Mussel samples from all sampling locations elicited significant dioxin-like activity in the H4IIE-luc bioassay. The greatest magnitude of dioxin-like response (39 pg TEQ/g wet wt.) was detected in mussels from Ma Wan in the western waters of Hong Kong, which is strongly influenced by the Pearl River discharge. Human health risk assessment was undertaken to evaluate potential risks associated with the consumption of the green-lipped mussels. Risk quotient (RQ) for dioxin-like compounds was greater than unity suggesting that adverse health effects may be associated with high mussel consumption.  相似文献   

The amino acid composition of estuarine colloidal material     

A.C. Sigleo  P.E. Hare  G.R. Helz 《Estuarine, Coastal and Shelf Science》1983,17(1):87-96

Amino acids were determined in estuarine colloidal and particulate material from near surface waters ranging from fresh to brackish water (12 g kg^?1 salinity). The hydrolizable amino acids and associated ammonia account for an average of 80% of the nitrogen present in colloidal samples, and approximately 75% of the nitrogen from particulate fractions of the same samples. The relative proportions of these amino acids are similar to those of a cultured estuarine diatom. There are no significant amounts of D amino acids, or non-protein amino acids characteristic of bacteria in sediments and soil. A single deep-water sample (25 m) shows some evidence of bottom mud resuspension by the presence of a possible aspartic acid-hydroxyproline dimer.  相似文献   

20世纪90年代初东亚夏季风的年代际转型   总被引：3，自引：1，他引：2       下载免费PDF全文

唐佳  武炳义 《应用气象学报》2012,23(4):402-413

利用1979—2009年JRA-25和NCEP/NCAR再分析资料,通过复矢量经验正交方法揭示了东亚地区夏季850 hPa风场变率的优势模态。结果表明:两套再分析资料所揭示的东亚夏季风在20世纪90年代初均发生了年代际转型,与我国夏季降水的年代际转型时间一致。伴随着东亚夏季风的年代际转型,我国北方大部分地区夏季降水减少,尤其是我国东北北部和长江、黄河之间105°E附近区域显著减少,而华南地区和淮河流域降水显著增加。从动力上解释我国夏季降水年代际转型特征,夏季500 hPa高度场两个时段 (1993—2009年和1979—1992年) 的差值分布显示为欧亚大陆北部准纬向遥相关波列,夏季850 hPa风场差值分布表现为贝加尔湖东南侧和日本以南地区存在两个异常反气旋式环流,而我国南方地区和鄂霍次克海附近均为异常气旋式环流。夏季西北太平洋、北印度洋以及部分中高纬度海洋的海温和春季欧亚大陆积雪在20世纪90年代初出现显著变化,春季北极海冰的年代际转型发生在20世纪90年代初,都可能成为东亚夏季风年代际转型的原因。  相似文献   

Composition and major sources of organic compounds in urban aerosols     

Xinhui Bi  Bernd R.T. Simoneit  Guoying Sheng  Shexia Ma  Jiamo Fu   《Atmospheric Research》2008,88(3-4):256-265

Total suspended particles (TSP), collected during June 2002 to July 2003 in Guangzhou, a typical economically developed city in South China, were analyzed for the organic compound compositions using gas chromatography–mass spectrometry (GC/MS). Over 140 organic compounds were detected in the aerosols and grouped into different classes including n-alkanes, hopanoids, polycyclic aromatic hydrocarbons, alkanols, fatty acids, dicarboxylic acids excluding oxalic acid, polyols/polyacids, lignin products, phytosterols, phthalates and water-soluble sugars. The total amounts of the identified organic compounds including unresolved complex mixture (UCM) ranged from 3112 ng/m³ in spring to 5116 ng/m³ in winter, comprising on seasonal average 2.8% of TSP. Primary organic compounds peaked in winter although there are no heating systems burning fuels in Guangzhou. The highest saccharide levels occurred in fall due to agricultural activities. This study demonstrated that utilization of fossil fuels, biomass burning, soil resuspension and plastic/refuse burning are the major contributors to the identified organic compounds in the urban atmosphere of South China.  相似文献   

黑龙江北部孙吴-嘉荫盆地构造特征、演化及石油地质条件   总被引：2，自引：0，他引：2       下载免费PDF全文

杨建国  吴河勇  王洪伟  林东成  姜丽娜 《地质科学》2009,44(2):679-691

重力解释孙吴-嘉荫盆地基底埋深一般在0.1～2.5 km,基底形态具有北东走向的“三断两隆”的构造特征,自西向东称孙吴断陷、茅栏河隆起、沾河断陷、富饶隆起和嘉荫断陷.地震解释基底深度一般在0.1～6.3 km,并据之进一步划分了断陷的次级构造单元.孙吴-嘉荫盆地的形成和演化与南部的松辽盆地颇为相似,大致经历了前裂陷、断陷、坳陷和萎缩4个阶段.下白垩统淘淇河组、上白垩统永安村组和太平林场组埋藏较深,厚度较大,烃源岩达到成熟阶段,储层发育,物性较好,为油气勘探的主要目的层.对沾河断陷和嘉荫断陷油气勘探有利区做了进一步预测,确定乌拉嘎凹陷是嘉荫断陷最有利的勘探区,确定沾河向斜是沾河断陷最有利的勘探区.  相似文献   

冀北小寺沟铜钼矿外围银金资源潜力浅析   总被引：6，自引：1，他引：5       下载免费PDF全文

孙冀凡  王会文  许振海 《地质找矿论丛》2004,19(1):20-23

小寺沟周边地区成矿地质条件十分优越,与燕山期中晚期陆相潜火山作用有关的多金属矿化广泛发育.在岩体内产有中大型规模的斑岩型铜钼矿床.近年来在其外围新发现一批银、金多金属异常,经初步评价已发现一具中型以上规模的银金矿床.本区具有系列成矿特征,银金资源潜力较大.  相似文献   

东营凹陷北部陡坡带稠油成藏机理与油气运聚特征   总被引：6，自引：1，他引：5  

李素梅  庞雄奇  邱桂强  高永进  孙锡年 《地球科学》2004,29(4):451-456,466

东营凹陷北部陡坡带的王庄—宁海地区发现了大量稠油 ,但原油的成因及其成藏机理仍不甚了解 .在以往原油成因与油源调查基础上 ,利用非烃含氮化合物及包裹体均一化温度对该区进行油气运移方向与相对距离、成藏时间与期次的分析 .结果表明 ,东营凹陷北部带原油具有由南而北的运移分馏效应 ,反映北部陡坡带原油来自南部的利津洼陷 ;王庄—宁海地区原油总体具有由东而西的运移分馏效应 ,其东、西两侧各有一主要油气注气点 .王庄—宁海原油烃类与非烃组成与分布特征揭示该区油气具有混合聚集特征 .包裹体测试反映王庄—宁海地区油藏主要为晚期成藏 ,距今小于 5Ma ;而靠近生油中心地带包裹体具有早期成藏的记录 (± 36Ma) .  相似文献   

南海北部油气缓释环境沉积物脂类化合物组成特征     

邱红  邹立  张民生  朱超祁  贾永刚 《沉积学报》2019,37(2):416-423

认识沉积环境有机碳留存状况是阐述油气形成过程中有机碳早期成岩的关键内容。以南海珠江口盆地及其邻近海域为背景,通过研究表层沉积物中脂类化合物的形态组成,认识脂类有机碳的来源和留存状态,阐述特征脂类分子的早期成岩特征。结果表明,研究区域表层沉积物有机碳含量为0.22%～0.66%,有机碳稳定同位素分布在-20.88‰～-22.93‰之间,表现为显著的海源特征。沉积物中共检测出21种脂肪酸、6种脂肪醇、8种甾醇和植醇;总脂肪酸、脂肪醇、甾醇和植醇含量分别为12.57～40.27μg/g、5.35～8.98μg/g、0.15～3.75μg/g和0.01～3.99μg/g干重,总体表现为靠近珠江口和台湾海峡略高。脂类化合物的存在形态以游离态(FR)和碱性水解态(BH)为主,酸性水解态(AH)贡献较低;其中植醇和甾醇呈现显著的BH优势,植醇中未检出AH组分的贡献。脂类化合物主要来自于海洋现场生产,海洋微藻和细菌的相对贡献率分别为21.18%～33.78%和11.02%～15.64%,陆源高等植物贡献低于5%。来源于硫酸盐还原菌的支链脂肪酸在靠近珠江口海域高达1.79～2.62μg/g,占总脂肪酸的5.14%～6.50%,并与硫酸盐还原过程相关的古菌分布相一致。  相似文献