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51.
海水养殖环境污染及控制对策   总被引:4,自引:0,他引:4  
随着我国海水养殖业的快速发展,养殖自身污染日益突出,并逐渐成为近岸海域的重要污染源。本文就海水养殖所带来的饵料污染、化学污染、生物污染及其环境效应等方面进行了综述,并重点从物理、化学、生物修复技术方面提出了海水养殖环境治理及控制对策。  相似文献   
52.
An oil-refining plant site located in southern Taiwan has been identified as a petroleum-hydrocarbon [mainly methyl tert-butyl ether (MTBE) and benzene, toluene, ethylbenzene, and xylenes (BTEX)] spill site. In this study, groundwater samples collected from the site were analyzed to assess the occurrence of intrinsic MTBE biodegradation. Microcosm experiments were conducted to evaluate the feasibility of biodegrading MTBE by indigenous microorganisms under aerobic, cometabolic, iron reducing, and methanogenic conditions. Results from the field investigation and microbial enumeration indicate that the intrinsic biodegradation of MTBE and BTEX is occurring and causing the decrease in MTBE and BTEX concentrations. Microcosm results show that the indigenous microorganisms were able to biodegrade MTBE under aerobic conditions using MTBE as the sole primary substrate. The detected biodegradation byproduct, tri-butyl alcohol (TBA), can also be biodegraded by the indigenous microorganisms. In addition, microcosms with site groundwater as the medium solution show higher MTBE biodegradation rate. This indicates that the site groundwater might contain some trace minerals or organics, which could enhance the MTBE biodegradation. Results show that the addition of BTEX at low levels could also enhance the MTBE removal. No MTBE removal was detected in iron reducing and methanogenic microcosms. This might be due to the effects of low dissolved oxygen (approximately 0.3 mg/L) within the plume. The low iron reducers and methanogens (<1.8×103 cell/g of soil) observed in the aquifer also indicate that the iron reduction and methanogenesis are not the dominant biodegradation patterns in the contaminant plume. Results from the microcosm study reveal that preliminary laboratory study is required to determine the appropriate substrates and oxidation-reduction conditions to enhance the biodegradation of MTBE. Results suggest that in situ or on-site aerobic bioremediation using indigenous microorganisms would be a feasible technology to clean up this MTBE-contaminated site.  相似文献   
53.
地浸采铀技术已成为世界采铀的主流工艺,采区退役后地下水环境修复亦为人们所关注的热点。文章简要介绍了碱法、中性和酸法三种典型地浸采铀技术的特点,系统分析了地浸采铀对地下水环境的影响,并以酸法地浸铀矿山地下水环境修复技术为例,重点介绍了物理化学修复技术和生物修复技术及其原理与应用,归纳总结了其优缺点,并对未来的研究方向进行了展望。指出下一步应加强在酸性与氧化环境中能使铀固定并长期稳定的新技术,高活性、强适应性修复菌群的选育、驯化技术,地下水异位-原位协同生物修复技术,以及放射性核素及重金属在铀矿地浸地下水环境中的吸附-解吸、氧化-还原、溶解-沉淀等行为与机理及其主控因素等方面的研究。  相似文献   
54.
Geobacter become dominant members of the microbial community when Fe(III)-reducing conditions develop as the result of organic contamination, or when Fe(III) reduction is artificially stimulated. These results suggest that further understanding of the ecophysiology of Geobacter species would aid in better prediction of the natural attenuation of organic contaminants under anaerobic conditions and in the design of strategies for the bioremediation of subsurface metal contamination. Received, May 1999/Revised, October 1999/Accepted, October 1999  相似文献   
55.
鼠尾藻对重金属锌、镉富集及排放作用的研究   总被引:5,自引:0,他引:5  
将鼠尾藻(Sargassum thunbergii)暴露在不同质量浓度锌和镉溶液里40 d,以及暴露20 d后,移入自然海水恢复20 d,分析了藻体内金属离子含量的变化。富集实验结果表明,鼠尾藻积累金属离子的量和暴露溶液金属质量浓度正相关、与暴露时间具有线性关系;暴露3 d,藻体的金属离子含量(除了暴露在Cd2+质量浓度为0.1 mg/L处理组)均显著增加;在Zn2+处理组,溶液里Zn2+质量浓度越大,线性关系越显著,而在Cd2+处理组,Cd2+质量浓度5.0 mg/L处理组藻体内Cd2+含量与暴露时间的线性关系则最低。排放试验结果表明,排放20 d后与排放0 d比较,藻体内的金属离子质量浓度均显著降低,但是均显著高于暴露前水平;在Zn2+溶液里,鼠尾藻暴露Zn2+质量浓度0.1 mg/L和Zn2+质量浓度5.0 mg/L 20 d后移入自然海水5 d后,藻体内的Zn2+含量与排放0 d相比显著降低,而在Cd2+溶液里,藻体排放5 d后,藻体内的Cd2+含量与排放0 d相比均显著降低。最终结果表明,鼠尾藻潜在地可作为一种指示生物,用于监测海洋环境重金属污染状况。同时,鼠尾藻对Zn2+和Cd2+具有较强的富集能力,可以利用鼠尾藻修复受重金属污染的海洋水体,尤其是锌的污染。  相似文献   
56.
Hexavalent chromium Cr(VI) has emerged as a contaminant of prime concern for the environmentalists because of its improper disposal by tannery, dye, and electroplating industries. Adsorption is the most exploited method for its removal from industrial wastewater because of its high removal efficiency even at low Cr(VI) concentration, minimal sludge, and ease of regeneration. In recent years, several adsorbents of biological origin such as plants, algae, fungi, and bacteria have been explored for Cr(VI) remediation. This review comprehends the recent studies involving usage of biopolymer-based nano-composites with respect to its adsorption mechanisms, adsorption capacities, isotherms, and kinetics. The conventional abiotic and biotic techniques for removal of Cr(VI) are also discussed with a comparative insight of their adsorption capacity and removal efficiency. Nano-biocomposites integrate the functional properties of both nanoparticles and biopolymers, which make them efficient biosorbents. Nano-biocomposites offer a large surface area, reduced particle loss, minimal particle agglomeration on the surface, and high stability. Common kinetic models among the nano-biocomposites,  and various equilibrium models are also analyzed to understand the mode of adsorption and associated factors. These materials are mostly found to follow monolayer adsorption with ion exchange, electrostatic interaction, and surface complexation as major players in the process.  相似文献   
57.
Pollution of petroleum hydrocarbons, in particular oil spills, has attracted much attention in the past and recent decades. Oil spills influence natural microbial community, and physical and chemical properties of the affected sites. The biodegradation of hydrocarbons by microorganisms is one of the primary ways by which oil spill is eliminated from contaminated sites. One such spill was that of the Russian tanker the Nakhodka that spilled heavy oil into the Sea of Japan on January 2, 1997. The impact of the Nakhodka oil spill resulted in a viscous sticky fluid fouling the shores and affected natural ecosystems. This paper describes the weathering of hydrocarbon-degrading bacteria (genus Pseudomonas) and crystallized organic compounds from the Nakhodka oil spill-polluted seashores after nine years. The Nakhodka oil has hardened and formed crust of crystalline paraffin wax as shown by XRD analysis (0.422, 0.377, and 0.250 nm d-spacing) in association with graphite and calcite after 9 years of bioremediation. Anaerobic reverse side of the oil crust contained numerous coccus typed bacteria associated with halite. The finding of hydrocarbon-degrading bacteria and paraffin wax in the oil crust may have a significant effect on the weathering processes of the Nakhodka oil spill during the 9- year bioremediation.  相似文献   
58.
The distribution of phytoplankton and its correlation with environmental factors were studied monthly during August 2012 to July 2013 in the Yantian Bay. A total of 147 taxa of phytoplankton were identified, and the average abundance was in the range of 0.57×10~4 to 7.73×10~4 cell/L. A total of 19 species dominated the phytoplankton assemblages, and several species that are widely reported to be responsible for microalgae blooms were the absolutely dominant species, such as Skeletonema costatum, Navicula sp., Thalassionema nitzschioides,Pleurosigma sp., and Licmophora abbreviata. The monthly variabilities in phytoplankton abundance could be explained by water temperature, dissolved oxygen, salinity, dissolved inorganic nitrogen(DIN), and suspended solids. The results of a redundancy analysis showed that p H and nutrients, including DIN and silicate(SiO_4), were the most important environmental factors controlling phytoplankton assemblages in specific months. It was found that nutrients and pH levels that were mainly influenced by mariculture played a vital role in influencing the variation of phytoplankton assemblages in the Yantian Bay. Thus, a reduction of mariculture activities would be an effective way to control microalgae blooms in an enclosed and intensively eutrophic bay.  相似文献   
59.
测定不同光强下菊花心江蓠(Gracilaria lichevoides)的产氧率和耗氧率.结果表明,20 000 lx以内菊花心江蓠的产氧率和光强的相关曲线的回归方程为y=0. 000 144 3x-0. 122 1,R2=0. 993 8,实验条件下菊花心江蓠的耗氧率为0. 121±0. 010 mg/(g·h),光补偿点为825 lx,光饱和点在20 000~22 000 lx之间,光饱和时的产氧率为2. 723±0. 329 mg/(g·h).光饱和以后菊花心江蓠的产氧率基本保持不变,45 000 lx以后出现轻微光抑制现象.测量水下光强随水深变化情况,发现水深达到水体透明度深度时,光强约14 000~15 000 lx,与菊花心江蓠的最大生长率的光强接近.测量不同养殖模式的溶解氧浓度昼夜变化,发现养殖密度过大可能在凌晨出现缺氧状态.根据菊花心江蓠的光合特性,提出江蓠养殖、江蓠用于生态修复的水深调控方法以及江蓠用于生态养殖的密度调控方法,以保持不同需求条件下较高的经济或生态效益.  相似文献   
60.
介绍了施加营养修复石油污染海滩的3个典型实例。Exxon Valdez溢油生物修复的研究中发现,以藿烷为内标,施加营养的生物降解速率比石油的自然清除速率快将近5倍。美国特拉华州的现场研究结果表明,孔隙水中维持初始N浓度为1~2 mg/L可以使降解率接近最大值;海滩上N的背景浓度很高时,即使不添加任何肥料,石油烃的生物降解也可接近最大值。英国对细颗粒沉积物的生物修复试验结果显示:在被石油污染的区块上施加营养物质使石油降解菌的数量增加了10倍,石油烃相对于藿烷的比值在施加肥料组和控制组中有显著的不同。此外,还对海滩石油污染生物修复过程中孔隙水中的最佳营养浓度、营养的施加频率及方法进行了综述。  相似文献   
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