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21.
纳米二氧化钛(TiO_2-NPs)是目前应用最为广泛的纳米材料之一,在城市污水处理厂的出水、污泥以及地表水体中已均有检出,进入到天然湿地和人工湿地中的TiO_2-NPs会在湿地生物、基质、水体之间进行迁移转化和归趋。目前针对TiO_2-NPs对湿地植物金鱼藻的毒性研究很少。本文采用水培实验方法,研究了不同粒径TiO_2对金鱼藻种子发芽和植株生长的影响,解析了TiO_2-NPs对金鱼藻的生态毒理效应。研究结果表明:各粒径TiO_2-NPs对金鱼藻种子的发芽均具有一定的抑制作用,表现为发芽率、发芽幼苗重量、发芽指数、发芽势和活力指数的降低,且粒径越小、浓度越高对金鱼藻种子发芽的抑制作用越强,4 nm、20 nm和50 nm的TiO_2-NPs对金鱼藻种子发芽的半数有效浓度(EC_(50))分别为1 180、1 520和1 810 mg·L~(-1)。TiO_2-NPs对金鱼藻植株的毒害作用表现为叶片失绿发黄、脱落,植株呈萎焉状,并且TiO_2-NPs的粒径越小、浓度越高毒害作用越明显。随TiO_2-NPs浓度升高,处理后金鱼藻叶片的叶绿素含量和植株体内的Mg含量均降低,丙二醛(malondialdehyde,MDA)含量均升高,而超氧化物歧化酶(superoxide dismutase,SOD)活性则先升高后降低,而且越小粒径的TiO_2-NPs对金鱼藻的处理效果越明显。3种粒径的TiO_2-NPs均能进入金鱼藻体内,粒径越小、浓度越高进入的量越多。综上表明,TiO_2-NPs对金鱼藻种子发芽和植株生长均有一定的抑制作用,且粒径越小、浓度越高抑制作用越强。  相似文献   
22.
抗生素与重金属复合污染的生态毒理效应研究进展   总被引:2,自引:0,他引:2  
随着越来越多的污染物进入环境,复合污染已经成为各类环境介质中普遍存在的现象,也是当前环境污染研究的重点方向之一。抗生素和重金属在环境中均具有持久性和毒性,且都对生态环境产生潜在长期的危害。重点论述了抗生素与重金属复合污染的生态毒理效应,以期为今后探索抗生素与重金属复合污染环境风险评价和污染治理提供一定参考,并对未来该领域需要进一步研究的问题和方向进行了展望。  相似文献   
23.
以土壤微生物生化过程与数量、土壤酶活性为指标,通过正交实验,在室内培养条件下探讨了Cd、Cu、Pb复合污染对土壤微生物的生态毒理效应.结果表明,1)Cd、Cu、Pb复合污染可显著降低土壤脲酶、蔗糖酶活性,对土壤过氧化氢酶和磷酸酶则表现出协同抑制或激活效应,不同重金属对土壤酶抑制效应顺序为Cd>Cu>Pb,土壤脲酶、蔗糖酶活性可作为指示土壤Cd、Cu、Pb复合污染程度的预警指标;2)不同微生物对Cd、Cu、Pb复合污染的敏感性为:细菌>放线菌>真菌,对微生物种群数量的影响强度为Cd>Cu>Pb;3)Cd、Cu、Pb复合污染对土壤微生物呼吸强度的影响较小,抑制率普遍较低,个别组出现激活作用.  相似文献   
24.
Aerosol leads to 30% reduction in solar radiation reaching the earth’s surface, and a similar reduction in crops yield for both wheat and rice. To determine the effect of aerosol wet deposition on crops, aerosol samples were collected in September, 2006 at Xi’an urban suburb (34?44 N, 109?49 E), and wheat seedlings were treated with aerosol of different concentrations in laboratory conditions. Changes in physiological and biochemical parameters of wheat seedlings were measured. In comparison with the control, the activities of superoxide dismudase (SOD) and catalase (CAT) and the concentration malondialdehyde (MDA) and oxidized glutathione (GSSG) of wheat seedlings increased progressively with increasing concentrations of added aerosol, while the opposite trend was seen for the activities of nitric oxide synthase (NOS), the concentrations of glutathione (GSH) and nitric oxide (NO), and the ratio of GSH/GSSG. When the seedlings were treated with the aerosol of 1 and 2 mg/L, the coleoptile elongation, shoot elongation and biomass accumulation were increased, the effect at treatment of 2 mg/L was most significant. However, aerosol treatments with rates of 3 and 4 mg/L resulted in a decrease in coleoptile elongation, shoot elongation and biomass accumulation in seedlings, and significant effect was for the treatment of 4 mg/L. Hence, lower concentrations of aerosol wet deposition were in favor of crops growth, but its higher concentrations could result in deleterious effects for crops and decreased crops growth.  相似文献   
25.
Bioassays as well as biochemical responses (biomarkers) in ecosystems due to environmental stress provide us with signals (environmentally signalling) of potential damage in the environment. If these responses are perceived in this early stage in ecosystems, the eventual damage can be prevented. Once ecosystem damage has occurred, the remedial action processes for recovery could be expensive and pose certain logistical problems. Ideally, “early warning signals” in ecosystems using sensing systems of biochemical responses (biomarkers) would not only tell us the initial levels of damage, but these signals will also provide us with answers by the development of control strategies and precautionary measures in respect to the European Water Framework Directive (WFD). Clear technical guidelines or technical specifications on monitoring are necessary to establish and characterise reference conditions for use in an ecological status classification system for surface water bodies. For the Ecotoxicological Risk Assessment (ERA) of endocrine effects we used an approach of the exposure – dose – response concept. Based on the “Ecototoxicological Classification System of Sediments” that uses pT-values to classify effects in different river systems, we transferred the bio-monitoring data to the five-level ecological system of the WFD. To understand the complexity of the structure of populations and processes behind the health of populations, communities and ecosystems an ERA should establish links between natural factors, chemicals, and biological responses so as to assess causality. So, our ecological monitoring assessment has incorporated exposure & effects data.  相似文献   
26.
三氯生的生态效应及其在环境中的迁移转化   总被引:3,自引:0,他引:3  
三氯生(triclosan)是一种广泛使用的抗菌剂和杀菌剂,主要添加于个人护理品等各类消费产品中。目前,三氯生在各种环境介质和生物体中普遍存在,其具有亲脂性、持久性、生物累积性和毒性,对生态环境和人类健康造成了潜在危害。归纳和分析了近年来国内外有关三氯生的研究成果,全面系统地介绍了三氯生在环境中的分布现状、生态效应和生物降解等,重点讨论了三氯生的环境毒性,以及三氯生杀菌的作用机制及其导致的细菌耐药性,最后对未来的研究工作进行了展望。  相似文献   
27.
污染土壤修复效果评定方法的研究   总被引:7,自引:0,他引:7  
在实施污染土壤修复的环境工程后,需要通过灵敏和有效的评定方法对污染土壤修复的效果进行评定。然而,单纯依靠化学方法进行污染土壤修复效果的评定,不能揭示土壤的整体质量特征,因此需要生态毒理方法作为相互补充的手段。本文概述了植物毒性评定法、陆生无脊椎动物评定法和土壤微生物评定法及其在污染土壤修复效果评定中的应用,并对污染土壤修复效果评定方法的发展前景进行展望。  相似文献   
28.
On 25 April 1998, as a consequence of the breaking of a dam containing the tailings of a pyrite mine, a land strip of approximately 43 km in length was covered with a layer of black sludge, containing high levels of heavy metals, along the Guadiamar River Basin (southern Spain). In this investigation we carried out an ecotoxicological assessment (field and laboratory studies) of the impact of residual heavy metals (Cu, Pb, Zn, Ni) on soil nematodes in the impacted riparian zone, two years after the huge mine spillage. Concentrations of residual heavy metals were significantly (P<0.05) higher at the impacted sampling sectors (S-2, S-3, S-4, S-5) than at the unpolluted (reference) sampling sector (S-1). Nickel however exhibited the lowest increases at the impacted sectors. As a consequence, correlation coefficients between concentrations of heavy metals and values of ecological indices were not significant for Ni. In contrast, copper, lead and zinc exhibited significant (P<0.05) negative correlation coefficients with ecological indices, particularly with diversity indices (including the~number of taxa). In addition, the toxicity of Cu and Pb to nematode test species (Aphelenchus avenae and Cephalobus persegnis) during short-term toxicity bioassays was much higher than the toxicity of Zn and Ni. We conclude that residual heavy metals were still influencing adversely the community of soil nematodes in the impacted riparian zone of the Guadiamar River Basin. Cu, Pb and, to a lesser extent, Zn would be major responsible for the observed impact.  相似文献   
29.
土壤生态毒理学研究进展与展望   总被引:21,自引:8,他引:21  
土壤生态毒理学是污染土壤生态风险评价以及土壤污染控制的理论依据,土壤环境中有毒物质的生态毒理效应及其分子机制的研究是土壤生态毒理研究的核心内容.首先从土壤重金属污染胁迫、有机污染胁迫以及复合污染的联合胁迫三个方面,概述了土壤污染所致的生态毒理效应最新研究进展;在理论剖析种群水平上污染土壤的分子生态毒理效应的基础上,较为系统地介绍了各种与污染土壤生态毒理效应有关的生物标记物,论述了污染土壤生态毒理分子诊断的基本原理、意义并对其今后的研究动态给予了分析;最后,对土壤生态毒理学研究今后的发展进行了展望.  相似文献   
30.
A new approach to environmental studies was investigated by the authors, who propose the use of cryopreserved biological systems in ecotoxicological bioassays. The feasibility of spermiotoxicity tests using cryopreserved semen of the sea bream Sparus aurata, with sperm motility parameters as the endpoint, was evaluated. Thawed sperm was incubated in environmental samples (sediment elutriate and dumpsite leachate) and in a reference toxicant (cadmium) at scaled concentrations. Motility was then evaluated by video-microscopy using both visual and computer-assisted analyses. Activation time, sperm motility and velocity and motility duration were assessed on thawing and at the end of the incubation time, and the difference with respect to the control was statistically evaluated. All the endpoints of the bioassay proved to have good sensitivity even at the highest dilutions of the tested matrices. Observed differences in the sensitivity thresholds of the endpoints were considered to be representative of different aspects of sperm physiology. Therefore the proposed bioassay is a promising starting point for the development of toxicity tests that are increasingly tailored to the needs of ecotoxicology and environmental quality evaluation strategies for aquatic environments.  相似文献   
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