野生动物重金属污染研究进展

重金属污染问题已成为全球热点,会对野生动物及环境造成严重危害。野生动物体内重金属主要来自食物链的传递,植物从空气和土壤中吸收重金属离子及其化合物,被采食后富集到草食性动物体内,逐级传递,最终会进入野生动物体内,对野生动物健康造成严重危害。体内重金属超标可以导致鸟类产生生殖障碍,降低种群数量,同时也会影响鸟类的行为。体内重金属超标会对哺乳动物骨骼发育、生殖健康等方面产生极大危害,对哺乳动物繁衍生息产生影响。文中主要综述重金属污染对野生鸟类、野生哺乳动物生长发育的影响;重金属在生物链传递过程的富集机制及其对野生鸟类、野生哺乳动物的毒理分子机制,以期对重金属环境污染的预防与治理提供理论基础。     

挥之不去的重金属

重金属一般以天然浓度广泛存在于自然界中,主要通过空气、水、土壤和食物等多种途径进入人体。环境中的重金属不能被降解,可通过食物链富集。环境中低浓度的重金属通过食物链中的富集作用,最终在人体内大量蓄积,破坏人体内正常生理代谢活动,损害人体健康。随着工业的发展,人类对重金属的开采、冶炼、     

牡蛎对重金属生物富集动力学特性研究

应用半静态双箱模型室内模拟了牡蛎对四种重金属 (As、Hg、Cd、Pb)的生物富集实验 ,通过非线性拟合得到了牡蛎富集重金属的吸收速率常数 k1 、排出速率常数 k2 、生物富集因子 BCF、生物学半衰期 B1 /2 等动力学参数。结果表明 :吸收速率常数 k1及生物富集因子 BCF均随着外部水体浓度的增大而减小而平衡状态下生物体内金属含量 CAmax随着外部水体浓度的增大而增大 ,且成显著正相关 ,这说明牡蛎比较理想的重金属 Hg、Cd、Pb污染的指示生物。     

挥之不去的重金属

重金属一般以天然浓度广泛存在于自然界中,主要通过空气、水、土壤和食物等多种途径进入人体。环境中的重金属不能被降解,可通过食物链富集。环境中低浓度的重金属通过食物链中的富集作用,最终在人体内大量蓄积,破坏人体内正常生理代谢活动,损害人体健康。随着工业的发展,人类对重金属的开采、冶炼、     

持久性有机污染物（POPs）对鸟类的影响

持久性有机污染物(POPs)是高残留物质,进入生物体后会长期存留并产生危害。近年来,有关生物体中POPs的研究已成为环境化学、生态毒理学研究的热点之一。本文概述了持久性有机污染物(POPs)的主要类型、生态特征、来源和污染效应。介绍了POPs在鸟类体内富集的特点及其对鸟类的危害;分析了以鸟类作为环境监测指示生物时应注意的问题;对POPs的防治以及利用鹭类等水鸟监测环境污染的方法提出了建议。     

重金属在海洋食物链中的传递

近年来 ,金属在不同海洋食物链中摄食富集的定量研究得到越来越多的关注。自然环境中生物体内金属的浓度并不一定和生物在食物链中所处的营养级有相关关系 ,金属在生物体内的富集还受到生物的同化、排出等过程以及其它生理生化因子的影响。在经典的海洋浮游生物食物链中 (浮游植物→桡足类→鱼类 ) ,桡足类往往可以很有效地排出体内的金属 ,同时鱼类的金属同化率又很低 ,所以该食物链中金属的浓度随食物链水平增加而减少。目前研究发现只有甲基汞和铯 Cs会被食物链所放大。在以腹足动物为顶级捕食者的底栖食物链中 ,因为生物结合金属的效率很高 ,高同化率和低排出率导致金属浓度在生物体内得到放大。重金属在生物体内的可利用性可以通过测定同化率、排出率等参数、并结合考虑生物对该金属的消化行为 ,运用一个简易的动态模型来估算。已有的研究中人们多考虑金属的化学性质对食物链传递的影响。着重介绍了近年来国外对金属在不同海洋食物链 (底栖和浮游 )中的传递的研究成果 ,强调在金属的生物可利用性评估中 ,要充分考虑到动物的生理、生化过程的影响 ,同时也必须认识到不同的海洋生物有着复杂且不同的金属代谢机制     

广州黄埔区夜鹭和池鹭体内汞浓度和分布特性

1　引　　言许多研究表明,汞是能在食物链中富集的重金属[2].汞对鸟类的危害受到广泛的关注,Sundlof等[12]学者指出,全球涉禽种群减少的部分原因可能是汞中毒.鸟类从食物中摄取的汞在体内组织中富集.在鸟的生长过程中,体内富集的汞释放入羽毛中,鸟类通过定期的换羽把汞排出体外.汞进入羽毛后牢固地与羽毛中的角蛋白结合,其生理和化学过程比较稳定,所以汞在羽毛中的浓度最高.有研究表明,博氏鸥(Larusphiladelphia)成鸟体内93%的汞存留在羽毛中,黑鸢(Milvusmigrans)体内70%的汞在羽毛中[1,9].羽毛中汞的浓度与鸟体内组织中汞浓度相关[4].其…     

关于生物富集的几个问题

在高级中学全一册(甲种本)《教学参考书》第七章的教学参考资料中,关于DDT的使用对环境和人类产生的影响的论述,引出了生物富集这一概念,他们的解释是“……象DDT这样的污染物,通过食物链就在各个营养级的生物体内逐级地浓集起来,这叫做污染物的生物富集。”并进一步解释“DDT在高位营养级动物体内的浓度,可以是最初营养级植物体内浓度的几千倍,甚至几十万倍。”“在食物链中,营养级越高,DDT积累的剂量越大,其毒害作用也就越明显。”如果按此给学生讲解,容易使学生产生以下误解:(1)生物富集必须在食物链上进行。(2)随着营养级的增高,生物体内的毒物浓度和     

海南万宁海域海洋生物重金属分析与评价

海洋经济生物体内重金属含量直接影响到人类健康。根据2020年12月对万宁海域12个调查站、10种生物(鱼类7种、软体类1种、甲壳类2种)体内的7种重金属(Cu、Pb、Zn、Cd、Cr、As、Hg)含量监测结果,分析了重金属的含量特征,并分别利用单因子污染指数法和重金属富集系数对重金属污染水平和它在生物体内的富集情况进行了评价。结果表明:(1)各类生物体内重金属含量的高低顺序不一致,但三类生物体内锌和铜的含量均相对较高。生物对必需元素锌和铜的富集明显高于对非必需元素铅、镉和总汞的,主动吸收能力明显。(2)不同类生物同种重金属的含量存在一定差异,甲壳类的高于鱼类和软体类的。万宁海域鱼类和软体类生物重金属单因子污染指数均小于1,部分甲壳类生物的铬单因子污染指数大于1,超标率为41.7%。铬是万宁海域海洋生物的主要污染因子,影响其含量的原因可能是周围的围填海工程,以及所研究物种的生理特性。(3)万宁海域甲壳类生物体内总汞已呈轻污染状态,铬呈重污染状态。(4)甲壳类生物对重金属的富集能力强于鱼类和软体类的,各类生物对Cu的富集能力最高,对As的富集能力最低,且对重金属Cu、Cd和Zn有潜在的严重...     

硅藻重金属污染生态学研究进展

硅藻是水生生态系统健康的指示生物之一,对环境变化极为敏感,某些典型硅藻已应用于指示水体重金属污染.本文围绕地表水重金属污染,从毒性效应、生物吸附和累积、生态适应机制及生物指示与生态修复作用等方面,综述了硅藻重金属污染生态学研究进展,阐述重金属污染下硅藻的生长趋势和硅壳形态的变化,硅藻对重金属生物吸附和生物累积的差别,硅藻对重金属的表面络合和离子交换等生态适应机制,以及硅藻对水体重金属污染的指示作用和生态修复作用,为水生生态系统的重金属污染防治与预警技术提供科学依据.     

Marine Birds as Sentinels of Environmental Pollution

Marine birds are useful as bioindicators of environmental pollution in estuarine and marine environments because they are often at the top of the food chain, ubiquitous, and many are abundant and common, making collecting possible. Seabirds have the advantage of being large, wide-ranging, conspicuous, abundant, long-lived, easily observed, and important to people. Many species are at the top of the food chain where they bioaccumulate contaminants with age. One disadvantage is that many species are migratory, making it difficult to determine where exposure occurred. This can be eliminated by using sedentary species or young birds that obtain all their food from parents. Further, noninvasive collection of feathers can be used to assess heavy metal levels, both from current collections and from historical collections in museums dating back centuries. Marine birds can be used as bioindicators in many ways, including tissue levels of contaminants, epidemiological field studies of effects, and experimental and laboratory studies of dose and effects. Examples from our research indicate some of the ways marine birds can be useful as indicators and sentinels of contamination, particularly by using young birds and feathers.     

Biomonitoring Heavy Metal Pollution Using an Aquatic Apex Predator,the American Alligator,and Its Parasites

Monitoring the bioaccumulation of chemical elements within various organismal tissues has become a useful tool to survey current or chronic levels of heavy metal exposure within an environment. In this study, we compared the bioaccumulations of As, Cd, Cu, Fe, Pb, Se, and Zn between the American alligator, Alligator mississippiensis, and its parasites in order to establish their use as bioindicators of heavy metal pollution. Concomitant with these results, we were interested to determine if parasites were more sensitive bioindicators of heavy metals relative to alligators. We found parasites collectively accumulated higher levels of As, Cu, Se, and Zn in comparison to their alligator hosts, whereas Fe, Cd, and Pb concentrations were higher in alligators. Interestingly, Fe levels were significantly greater in intestinal trematodes than their alligator hosts when analyzed independently from other parasitic taxa. Further analyses showed alligator intestinal trematodes concentrated As, Cu, Fe, Se, and Zn at significantly higher levels than intestinal nematodes and parasites from other organs. However, pentastomids also employed the role as a good biomagnifier of As. Interestingly, parasitic abundance decreased as levels of As increased. Stomach and intestinal nematodes were the poorest bioaccumulators of metals, yet stomach nematodes showed their ability to concentrate Pb at orders of magnitude higher in comparison to other parasites. Conclusively, we suggest that parasites, particularly intestinal trematodes, are superior biomagnifiers of As, Cu, Se, and Zn, whereas alligators are likely good biological indicators of Fe, Cd, and Pb levels within the environment.     

拟水狼蛛对食物中镉的吸收和排泄及生物学响应

为明确拟水狼蛛对食物中镉的吸收和排泄及生物学响应,采用原子吸收光谱法检测了连续3代拟水狼蛛对食物中Cd²⁺的吸收和排泄情况,并测定了Cd²⁺对其生长发育、繁殖力和耐饥力的影响。结果表明:食物中过量的Cd²⁺能够通过食物链进行传递并在拟水狼蛛体内积累,积累量随拟水狼蛛代数的增加而增加,第2代和第3代拟水狼蛛体内Cd²⁺积累量浓度显著高于第1代中Cd²⁺积累量,第2代和第3代间差异不显著,积累量与消耗的黑腹果蝇数量极显著正相关,P<0.01;与消耗食物中Cd含量显著正相关,P<0.05。连续3代拟水狼蛛分别吸收了食物中65.4%、68.5%和69.1%的Cd,生物营养级放大因子分别为1.71、2.12和2.17。连续3代拟水狼蛛Cd排泄量极低。Cd处理能显著改变拟水狼蛛背胸甲宽、幼蛛存活率、生长历期和繁殖力。随拟水狼蛛受胁迫代数的增加,幼蛛存活率显著减少,生长历期显著延长。卵袋重量显著减轻,卵数目显著减少,卵体积显著升高。Cd处理还能显著降低拟水狼耐饥力。研究结果可为进一步研究环境中Cd沿土壤-昆虫-天敌传递、放大和生理耐受提供更为充分的理论依据。     

Nematodes as Sentinels of Heavy Metals and Organic Toxicants in the Soil

Field and laboratory research has repeatedly shown that free-living soil nematodes differ in their sensitivity to soil pollution. In this paper, we analyze whether nematode genera proved sensitive or tolerant toward heavy metals and organic pollutants in six long-term field experiments. We discuss overlaps between nematode physiological responses to heavy metals and to organic pollutants, which may explain why nematodes can exhibit co-tolerance toward several contaminants. We propose a simple method for separating direct effects of soil contamination on nematode populations from indirect effects mediated through the food chain. Finally, we analyze the extent to which nematodes exhibited consistent responses across the experiments analyzed. Our results show that (a) indirect effects of pollution were generally strong; (b) fewer nematode genera were tolerant than sensitive; (c) many genera, including practically all Adenophorea, exhibited a common response pattern to contaminants; and (d) several genera of the Secernentea exhibited differential tolerance toward particular pollutants. We conclude that bioindication of soil contamination should preferentially be based on tolerant, and less on sensitive, nematodes. We provide a list of nematode genera that may potentially serve as differential bioindicators for specific soil contaminants.     

重金属污染影响植食性昆虫的研究进展

重金属污染是世界各国面临的最为棘手的问题之一,对生态系统和食品安全构成了严重威胁。作为生态系统中食物链和食物网的重要环节,植食性昆虫是环境中重金属迁移、积累的重要媒介,其因重金属污染而受到的影响引起了大家的关注。本文综述了从2007至2018年重金属污染对植食性昆虫影响的研究进展。昆虫受重金属胁迫的研究途径有人工饲料添加、野外田间暴露、“土壤-植物-昆虫”食物链传递以及体外注射等。积累在植食性昆虫体内的过量重金属可导致其存活率、繁殖力和种群增长率降低,生长发育迟缓。重金属污染对植食性昆虫的生理生化毒性包括细胞超微结构破坏和DNA损伤,体内能量物质含量降低,酶活性、基因表达改变等。植食性昆虫会通过重金属硫蛋白、解毒酶活性的诱导等机制抵御重金属的毒害,从而对低浓度、长期重金属暴露产生生态适应性,甚至提高对其他逆境(如农药等)的耐受性。     

Challenging the model for induction of metallothionein gene expression

Metallothioneins (MTs) are low-molecular-weight, cysteine-rich metal-binding proteins found in a wide variety of organisms including bacteria, fungi and all eukaryotic plant and animal species. MTs bind essential and non-essential heavy metals. In mammalian cells MT genes are highly inducible by many heavy metals including Zn, Cd, Hg, and Cu. Aquatic systems are contaminated by different pollutants, including metals, as a result of man's activities. Bivalve molluscs are known to accumulate high concentrations of heavy metals in their tissue and are widely used as bioindicators for pollution in marine and freshwater environments, with MTs frequently used as a valuable marker of metal contamination. We here describe the MT isoform gene expression patterns of marine and freshwater molluscs and fish species after Cd or Zn contamination. Contamination was carried out at a river site polluted by a zinc ore extraction plant or in the laboratory at low, environmentally relevant metal concentrations. A comparison for each species based on the accumulated MT protein levels often shows discrepancies between gene expression and protein level. In addition, several differences observed in the pattern of MT gene expression between mollusc and mammalian species enable us to discuss and challenge a model for the induction of MT gene expression.     

Pollution characteristics and risk assessment of heavy metals in the soil of a construction waste landfill site

Heavy metals found in construction waste can enter soil and water bodies through surface runoff and leachate, where they represent an environmental hazard. In this study, we investigate the pollution characteristics and ecological risks of eight heavy metals (Cd, Cr, Cu, Mn, Ni, Pb, Zn, and As) in the soils of an unofficial construction waste landfill site in Beijing, China. The results indicate that long-term disposal of construction waste in the dry riverbed can reduce the pH value of the soil, increase the soil organic carbon content, and affect the total amount and distribution of heavy metals. Moreover, the landfill site pollutes the external soil environment, with Cd, Zn, Pb, and Cu as the characteristic pollutants. According to the Nemerow comprehensive pollution index and potential ecological risk assessment, heavy metal pollution decreases in the following order: internal soil > bottom soil > boundary soil. Cd, Zn, Pb, and Cu pollution is higher in the internal region, with single heavy-metal pollution indexes (Pi) of 1.41, 1.65, 1.26, and 1.28, respectively. Conversely, the Pi for Cr is higher in boundary and bottom soils (1.91 and 1.94, respectively). Risk assessment codes indicate that Cd and Mn pose the greatest environmental risk (31.9% and 17.8%, respectively) as they have the highest effective content, bioavailability, and mobility. Thus, environmental monitoring is a necessity for these metals.     

Environmental pollution affects genetic diversity in wild bird populations

Many common environmental pollutants, together with nuclear radiation, are recognized as genotoxic. There is, however, very little information on pollution-related genetic effects on free-living animal populations, especially in terrestrial ecosystems. We investigated whether genetic diversity in two small insectivorous passerines, the great tit (Parus major) and the pied flycatcher (Ficedula hypoleuca), was changed near point sources of heavy metals (two copper smelters) or radioactive isotopes (nuclear material reprocessing plant). We measured concentration of heavy metals and nucleotide diversity in mitochondrial DNA in feather samples taken from nestlings in multiple polluted areas and at control sites. In both species, heavy metal concentrations - especially of arsenic - were increased in feathers collected at smelter sites. The P. major population living near a smelter showed significantly higher nucleotide diversity than a control population in an unpolluted site, suggesting increased mutation rates in a polluted environment. On the contrary, F. hypoleuca showed reduced nucleotide diversity at both smelter sites but increased nucleotide diversity near the source of radioactivity. Our results show that heavy metal pollution and low level nuclear radiation affect the nucleotide diversity in two free-living insectivorous passerines. We suggest that the different response in these two species may be due to their different ability to handle toxic compounds in the body.     

环境重金属污染物的生物有效性

利用生态系统研究了白银有色金属冶炼矿区周围环境中重金属的分布及生物有效性。结果表明 ,工厂在冶炼过程中已造成 Pb、Cd、Cu、Zn对周围环境不同程度的污染 ,其含量与距工厂的距离呈负相关 ;重金属在各种生物体内均有不同程度的吸收和累积 ,其吸收累积量随重金属和生物种类的不同而有差异 ;土壤的污染 ,使农作物和牧草中 Pb、Cd含量超过动物的最大耐受量和中毒的临界值 ;动物研究发现 ,肾脏、骨骼和肝脏是机体内重金属蓄积的主要器官。因此 ,放牧动物可作为环境重金属污染状况的标识 ,对评价重金属环境污染对当地人群的危害也有重要意义     

Functional expression of a bacterial heavy metal transporter in Arabidopsis enhances resistance to and decreases uptake of heavy metals

Large parts of agricultural soil are contaminated with lead (Pb) and cadmium (Cd). Although most environments are not heavily contaminated, the low levels observed nonetheless pose a high risk of heavy metal accumulation in the food chain. Therefore, approaches to develop plants with reduced heavy metal uptake are important. Recently, many transgenic plants with increased heavy metal resistance and uptake of heavy metals were developed for the purpose of phytoremediation. However, to reduce heavy metal in the food chain, plants that transfer less heavy metals to the shoot are required. We tested whether an Escherichia coli gene, ZntA, which encodes a Pb(II)/Cd(II)/Zn(II) pump, could be useful for developing plants with reduced heavy metal content. Yeast cells transformed with this gene had improved resistance to Pb(II) and Cd(II). In Arabidopsis plants transformed with ZntA, ZntA was localized at the plasma membrane and improved the resistance of the plants to Pb(II) and Cd(II). The shoots of the transgenic plants had decreased Pb and Cd content. Moreover, the transgenic protoplasts showed lower accumulation of Cd and faster release of preloaded Cd than wild-type protoplasts. These results show that a bacterial transporter gene, ZntA, can be functionally expressed in plant cells, and that that it may be useful for the development of crop plants that are safe from heavy metal contamination.