Total oxyradical scavenging capacity and cell membrane stability of haemocytes of the Arctic scallop, Chlamys islandicus, following benzo(a)pyrene exposure     

L. Camus  M. B. Jones  J. F. Brseth  B. E. Grsvik  F. Regoli  M. H. Depledge 《Marine environmental research》2002,54(3-5)

Industrial activities, notably oil and gas industries, are expanding in the Arctic. Most of the biomarkers were developed using temperate organisms living at temperatures above 10 °C. Little is known about the biomarker responses of organisms living between −1.88 and 5 °C. Therefore, assessment of the toxicity of chemicals to cold-water adapted species is required. In this study, the Arctic scallop, Chlamys islandicus, was selected as a key species for bio-monitoring because of wide distribution in Arctic waters and its commercial value. Test animals, stored in seawater at 2 °C, were injected with benzo(a)pyrene (diluted in cod liver oil 5 mg ml⁻¹) in the adductor muscle every 24 h for four days giving a final dose of 0, 74 and 90.6 mg kg⁻¹ wet weight for control, low and high dose, respectively. The biomarkers used were total oxyradical scavenging capacity (TOSC) in the digestive gland and cell membrane stability of haemocytes. TOSC values were significantly reduced (ca. 30%) in exposed groups (P<0.05), indicating a depletion in oxyradical molecular scavengers. The antioxidant defences appeared to be overwhelmed by the reactive oxygen species as the plasma membranes of haemocytes were destabilised (P<0.05) probably due to lipid peroxidation. These data indicate that reactive oxygen species (ROS) were produced by Arctic scallops via the metabolisation of benzo(a)pyrene at 2 °C.  相似文献   

Biomarker responses in Macoma nasuta (Bivalvia) exposed to sediments from northern San Francisco Bay     

Ingeborg Werner  Swee J. Teh  Seema Datta  XiaoQiao Lu  Thomas M. Young 《Marine environmental research》2004,58(2-5):299

Our study investigates biomarker responses and survival of Macoma nasuta exposed to sediments collected from six locations in northern San Francisco Bay. Biomarkers analyzed were stress proteins (hsp70) in gill, mantle and digestive gland, lysosomal membrane damage and histopathologic lesions. Sediments and clam tissues were analyzed for a comprehensive suite of heavy metals and trace organic pollutants. Sediment grain size and organic carbon content were determined. Clams accumulated metals, polyaromatic hydrocarbons (PAHs) and organochlorine pesticides (aldrin and p,p^′-DDT and its metabolites p,p^′-DDD and p,p^′-DDE). Pearson and Spearman correlation analysis revealed that mortality, hsp70 in gill and histopathologic lesion scores in gonads, and lysosomal membrane damage were significantly correlated with tissue concentrations of DDT and/or its metabolites. Tissue concentrations of metals, in particular nickel, chromium, and copper, were associated with macrophage aggregates in digestive gland and germ cell necrosis. Cadmium was linked to mortality and lysosomal membrane damage.  相似文献   

UV-B辐射对2种海洋微藻膜脂过氧化和脱酯化伤害     

王军  肖慧  冯蕾  蔡恒江  唐学玺 《中国海洋大学学报(自然科学版)》2006,36(5):763-766

研究海洋生态系统在调节全球变化中的作用,采用生态毒理学的方法研究了UV-B辐射增强对2种海洋微藻膜的损伤及其差异性。结果表明,随着UV-B辐射剂量的增加,叉鞭金藻(Dicrateriasp.)和三角褐指藻(Phaeodactylum tricornu-tum)的光合速率降低。同时,膜相对透性增大,细胞内H2O2含量上升,微粒体膜中磷脂减少,游离脂肪酸增加。表明UV-B辐射增强使2种微藻的膜受到了严重伤害,而且膜伤害的加剧与活性氧的积累和由此引发的膜脂脱酯化有关。2种微藻细胞匀浆中丙二醛(MDA)含量无显著变化,而微粒体膜的MDA含量随着UV-B辐射剂量的加大显著提高。这表明UV-B辐射增强对2种海洋微藻膜的损伤可能是由膜脂过氧化和脱酯化作用共同引起的。  相似文献   

锯缘青蟹皮层反应与受精膜形成研究   总被引：3，自引：0，他引：3  

康现江  李少菁  王桂忠  陈锦民 《海洋科学》2001,25(1):40-43

锯缘青蟹成熟卵子排出时具有两层卵黄膜，卵子排出后形成壳膜，与卵子附着有关。成熟卵子具有两种皮层颗粒，精子入卵后，皮层反应开始，两种皮层颗粒相继胞吐。首先由致密颗粒胞吐，形成一层很薄的膜性结构，接着环形颗粒大量胞吐，其内含物融合，并与外面薄层融合为受精膜。卵子质膜由于皮层颗粒胞吐作用形成镶嵌膜。  相似文献   

联合机制下黏土垫层多离子扩散模型     

张志红  韩林  吕清硕 《岩土力学》2022,43(2):539-548

扩散是工程领域中的一种重要现象,尤其是针对填埋场底部的压实黏土垫层。扩散过程受多种因素影响,如离子种类、离子价态和离子浓度等,因此建立准确的扩散模型对填埋场垫层系统设计和评估具有极其重要的意义。引入简化的Guntelberg活度系数表示真实溶液与理想溶液浓度值的偏差,采用化学势和扩散势共同表征多离子扩散的驱动力,并考虑黏土介质特有的半透膜性能对离子扩散规律的影响,建立了复杂机制联合作用下多组分并存时离子在黏土垫层中的扩散模型。采用多物理场仿真软件COMSOL Multiphysics对所建扩散模型进行数值求解,结果表明,黏土半透膜效应、溶液非理想性和扩散势均显著影响多离子扩散行为,考虑黏土半透膜效应及溶液非理想性条件下,多离子扩散进程明显减缓,考虑扩散势时,阳离子扩散速度显著提高。复杂机制联合作用下,多离子扩散规律并非单一影响机制的简单叠加,各机制之间相互制约共同影响多离子扩散行为。  相似文献   

Uptake and depuration of PAHs and chlorinated pesticides by semi-permeable membrane devices (SPMDs) and green-lipped mussels (Perna viridis)     

Bruce J. Richardson  Edmund S.-C. Tse  Sharon B. De Luca-Abbott  Michael Martin  Paul K.S. Lam 《Marine pollution bulletin》2005,51(8-12):975

Semi-batch seawater experiments were conducted to follow the uptake and release of selected PAHs (anthracene, fluorathene, pyrene and B[a]P) and organochlorine pesticides (α-HCH, aldrin, dieldrin, p,p′-DDT) in semi-permeable membrane devices (SPMDs) and green-lipped mussels (Perna viridis). Mathematical models were applied to describe the uptake and elimination curves of the contaminants for SPMDs, and kinetic parameters, such as uptake rate constants, and equilibrium triolein/water partitioning coefficients were calculated. SPMD data showed a good fit to estimate rate constant and partition coefficient equations, but only those contaminants which partitioned mainly in the dissolved phase (α-HCH and dieldrin) were well explained for mussels. Poor conformity of the other contaminants indicated mussels uptake by routes other than diffusion, such as ingestion of algae. An apparent equilibrium state was only noted for α-HCH in mussels. Aldrin was not detected in mussels in the first few days of exposure, indicating potential metabolism of this compound. B[a]P was not detected in the triolein of SPMDs, which suggests that the membrane may act as a reservoir. Loss of spiked B[a]P from the triolein was evident in a depuration experiment, which may indicate transfer to the membrane. Rate constants for mussels were higher than those for SPMDs, but the reverse was true for partition coefficients. Overall, mussels and SPMDs had similar uptake rates for all compounds in this study, excluding p,p′-DDT and dieldrin. Contaminant elimination took place more rapidly in mussels, implying that SPMDs are better candidates for detecting episodic discharge of organic contaminants.  相似文献   

Electrokinetic remediation of an electroplating site: design and scale-up for an in-situ application in the unsaturated zone   总被引：1，自引：0，他引：1  

S. Wieczorek  H. Weigand  M. Schmid  C. Marb   《Engineering Geology》2005,77(3-4):203-215

In-situ electrokinetic remediation of contaminated soils requires integrated approaches and adequately engineered setups to control relevant mass fluxes. Based on laboratory findings, this study presents the design of a pilot-scale remediation at an operating electroplating site. The fine-textured soil developed from Jurassic limestone exhibits a chromium, copper, nickel, and zinc contamination down to depths of more than 4 m. The feasibility of an electrokinetic remediation in the unsaturated zone was tested in a lab-scale experiment with subsoil material sampled at the site. The electrodes were placed in water-impermeable, ion-selective membrane wells. This construction allows the necessary watering of the electrodes, maintains unsaturated conditions in the soil compartment, and enables the transfer of contaminant ions into the wells. In addition, the soil is protected from pH changes caused by water electrolysis at the electrodes. The setup includes a watering and drainage system to compensate the electroosmotic water flux and impede desiccation of the anodic region. With a direct current of 70 V and an electric field strength of 2.2 V cm⁻¹, contaminant removal rates amounted up to 27% and 66% (w/w) of the initial zinc/copper and chromium/nickel concentrations. Copper, nickel, and zinc accumulated in the cathode well, while chromate species were enriched in the anode well. Given the successful lab-scale remediation, the pilot plant was designed for the in-situ treatment of a soil volume of 12 m³ below a production hall. A power of 500 V DC at a maximum current of 30 A is supplied by a transformer rectifier. This yields an electric field strength comparable to the lab-scale experiment and thereby similar contaminant transport velocities. A vacuum distillation unit is employed for process water reuse and to control electrolyte conductivity. To cope with chlorine gas generation at the anodes a gas absorber unit is employed. According to the lab-scale results, about 2, 9, 9, and 15 kg zinc, chromium, copper, and nickel, respectively, are expected to be removed from the field plot during an operation time of 10 months.  相似文献   

Development of a Two‐Tier Fibrous Membrane by Sequential Electrospinning for Effective Air Filtration          下载免费PDF全文

Sowndarya Ramachandran  Sheeja Rajiv 《洁净——土壤、空气、水》2018,46(6)

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土壤石油污染物微生物降解机理与修复技术研究   总被引：13，自引：0，他引：13  

王红旗  陈延君  孙宁宁 《地学前缘》2006,13(1):134-139

较为系统地概述了土壤石油污染物的微生物修复技术和近年来石油烃代谢机理以及微生物细胞膜转运石油烃机理研究等方面的进展。文中着重讨论烷烃代谢途径、影响烷烃降解酶合成的阻遏物和激活物、芳香烃代谢过程和基因方面的研究,以及细胞膜结构的改变和石油烃的迁移等重要特性,最后从宏观系统的修复技术和微观分子学方面探讨微生物降解石油污染土壤的发展方向。  相似文献   

基于改进Terzarghi方法的桩网地基桩土应力计算     

黄宇华  徐林荣  周俊杰  蔡雨 《岩土力学》2020,41(2):667-675

桩土应力比是桩网复合地基承载力和沉降计算的重要参数,其与地基的固结沉降相关,具有明显的时变特性。已有基于Terzarghi土拱模型的松动土压力计算理论是在滑动面土体均达到极限状态的假定上讨论的,不适用于桩网地基小变形条件下桩土应力的计算。为此,在Terzarghi模型的基础上,相对位移面摩阻力传递函数采用等刚度理想弹塑性模型,结合土体单元的平衡方程与变形协调方程,导出了桩土应力及土拱高度理论解,系统分析了桩土应力及拉膜效应随各设计参数的定量变化规律。分析结果表明,改进方法与现有土拱效应模型相比适用性较好,随着桩土差异沉降增加,土拱高度和桩土应力比逐渐增大,土拱率呈双曲线形减小,同时拉膜效应逐渐发挥。增加填筑荷载对土拱效应有显著削弱作用,桩土应力比随桩距增大而减小,随黏聚力增大而增大。结合改进方法与已有现场实测数据,分析了桩土应力的时变特性,验证了该方法的合理性,可为桩网地基桩土应力计算提供参考。  相似文献