河流汞污染对青鳉鱼早期发育的毒性影响

清镇市化工厂是贵州省东门桥河汞污染的重要来源。为了评估这条河流的汞污染程度,本研究调查了东门桥河环境样品中的汞含量和分布情况。河流水体总汞(THg)和甲基汞(MeHg)的平均含量分别为(135.79±47.40)和(0.64±0.58) ng·L^-1;生物膜中THg和MeHg的平均含量分别为(3.38±1.91) mg·kg^-1和(10.47±0.40)μg·kg^-1;沉积物中THg和MeHg的平均含量分别为(23.21±20.22) mg·kg^-1和(32.74±10.96)μg·kg^-1。为了进一步了解这条河流中汞对水生生物的风险,将青鳉鱼胚胎和仔鱼分别暴露于从河中收集的被汞污染的河水、生物膜和沉积物中。青鳉鱼胚胎经15 d暴露后,孵化时间延长、孵化率显著降低,死亡率显著升高,实验暴露还导致胚胎无法破膜、卵黄囊水肿等畸形效应,以及初孵仔鱼不同程度的畸形。青鳉鱼仔鱼经24、48、96 h和21 d暴露后,各暴露组的死亡率和畸形率随着暴露时间的延长而显著升高,且表现出一系列以脊...     

六种选矿药剂对藻类的毒性比较

本文评价了六种选矿药剂对藻类的毒性效应,它们对斜生栅藻的毒性大小排列顺序是:二号油>Fu>0145>Yx>MPA>S-808,96h-EC_(50)值分别为41.2,50.1,82.0,177.8,198.2和900ppm。六种选矿药剂对藻类毒性最大的是二号油,毒性最小的是S-808。对藻类细胞形态的观察结果表明,0145对藻类的细胞形态有轻度的致畸效应,在其它五种药剂的培养物中,均未发现畸变细胞。在室温下存放10d后MPA,0145和二号油,毒性明显下降,其下降速率的顺序是:MPA>0145>二号油。藻类对S-808具有净化脱色作用,100ppm浓度的S-808溶液经藻类作用32d后,其色度可减少48％,作用62d和93d,色度分别降低54％和58％。0145抑制藻类的光合放氧,经50,100和200ppm浓度的0145处理4h后,与对照相比,藻类的光合放氧速率分别下降15、34和36％。     

汞矿山环境汞污染研究进展

汞矿山开采对周边环境的汞污染一直受到关注,尽管全球多数汞矿山已经相继停产、闭坑,但这些废弃的汞矿山仍然通过采矿所遗留的尾矿等固体废弃物、坑道废水和污染的土壤等对当地的环境和居民健康产生着持续的影响和危害.本文总结了环境样品中各形态汞的分析方法,评述了全球范围内汞矿的分布以及汞矿山开采和冶炼过程所造成的环境影响,提出了对于污染治理和风险评价的展望.     

环境有机污染物对藻类生长作用的研究进展

随着现代工农业的迅速发展和城市人口的增加 ,越来越多的工业废弃物、残留农药、生活垃圾等有机污染物通过各种途径进入到环境中。这些有机污染物主要包括两大类 ,它们分别是有机无毒物和有机有毒物。       

汞对慈姑活性氧代谢和染色体的影响

研究了不同浓度Hg2 以及处理时间对慈姑叶和根的活性氧(reactive oxygen species,ROS)和染色体的影响。结果显示：汞能诱导慈姑叶和根大量产生ROS,其中H2O2的突发早于O2。0．5-5mg／L处理组染色体畸变率(Chromosomal aberrant frequency,CAF)和微核率(micronucleus frequency,MCNF)在72h内与处理浓度、时间呈正相关。CAF、MCNF所反映的细胞遗传毒性的大小主要取决于汞处理浓度,而ROS则起次要作用。H2O2很可能在慈姑抵御汞胁迫中起信号传导作用;慈姑通过促进根部部分细胞死亡提高抗汞能力。     

水葫芦对藻类的克制效应

水葫芦对藻类生长有克制作用。其机制主要是由于水葫芦根系向水体分泌的有机物质能伤害和杀死藻类。用水葫芦种植水培养藻类,使藻类的光合作用速率显著降低,叶绿素a破坏,细胞还原TTC的能力下降。在荧光显微镜下可看到藻细胞从鲜红色变为淡蓝绿色。     

三峡库区汞污染的化学生态效应

测定长江三峡库区江段鲤、铜鱼、鲇、长吻中的砷、镉、铜、汞、铅、硒、锌等元素的含量。比例匹配分析表明,样品或元素间无显著相关。铜鱼、鲤、鲇及长吻对汞的富集系数分别为8．0×103、1．5×104、3．3×104、8．4×104（L／kg）。这表明鱼体汞元素含量与鱼类在食物链营养级的位置密切相关,食物链越长,汞的富集系数越高。鲤、鲇及长吻的肌肉、肝、肾和牌间的汞含量比值约为6：2：1,而铜鱼为1：1：2．5。三峡库区降低鲤、鲇及长吻的肌肉有机汞含量占总汞含量的84％－92％,肝、肾和脾的有机汞占总汞的55％－77％。但铜鱼脾中的无机汞约占总汞的89％。并且有机汞与总汞含量间具有显著地线性关系：肌肉：Hg－o＝－0.001094＋0．9101Hg-gP＜0．01这表明鱼体肌肉是储存有机汞主要组织。并且鱼体肌肉汞元素含量C与鱼的体长L或体重W间满足经验方程：LnC＝A＋BLnLLnC＝A'＋B'LnW三峡库区江段因受川东高汞背景的影响,鲤肌肉汞含量高于长江水系鲤汞含量的背景水平。     

除草剂扑草净和阿特拉津对海草与大型藻类的毒性比较

陆地径流等可引起海域中除草剂浓度升高, 从而威胁海洋大型植物——海草和大型藻类的生长。以叶绿素荧光为主要指标测定除草剂阿特拉津和扑草净的低、中、高(1、5和25 μg/L)浓度对4种常见海草:大叶藻(Zostera marina L.)、丛生大叶藻(Z. caespitosa M.)、矮大叶藻(Z. japonica Aschers. & Graebn.)、红须根虾形藻(Phyllospadix iwatensis M.)和2种常见大型藻类:孔石莼Ulva lactuca L.和海索面Nemalion helminthoides的光合抑制。结果显示, 低浓度1 μg/L的扑草净和5 μg/L的阿特拉津即对矮大叶藻、孔石莼和海索面产生了显著的光合抑制, 抑制率约而7.54%—12.97%; 大叶藻、丛生大叶藻和红须根虾形藻的扑草净和阿特拉津的显著作用浓度为5 μg/L, 在相同浓度下, 扑草净的光合抑制较阿特拉津更强, 同时, 矮大叶藻及两种大型藻类较其他3种海草成体对除草剂作用更为敏感。     

藻类污染生物防治新策略

1　水体藻类污染生物防治的必要性近些年来由于污染造成的环境恶化逐步加重 ,水体藻类污染的程度也逐年加深。赤潮或水华 (ＲｅｄｔｉｄｅｏｒＢｌｏｏｍ)在全球范围内频繁出现是藻类污染程度加深的直接反映。我国在 1 933年到 1 979年的 46年中仅发生过 1 2次赤潮 ,而 1 990年到 1 994年的 5年中就发生了 1 39次赤潮 ,藻类污染灾害日趋严重。赤潮可以造成海水ｐＨ值升高 ,粘稠度增大 ,改变浮游生物的生态系统群落结构。当赤潮藻类过度密集或死亡腐解时 ,又造成了海域大面积的缺氧 ,甚至无氧。藻细胞代谢及腐解又会产生大量有害气体和毒素 (…     

Temperature and species differences in susceptibility of kidney cell cultures to mercury toxicity

Summary The effect of temperature on inorganic mercury toxicity was investigated using kidney tissue culture systems. The relative susceptibility of rabbit (homeothermic) kidney to mercury intoxication was compared to that of Coho salmon (poikilothermic) kidney over temperature ranges consistent with the habitat of each of the two species. It was demonstrated that susceptibility to mercury toxicity is species dependent; that is, the rabbit kidney cells tolerated higher mercury concentrations in the medium than did the fish-derived cells. Within a given species, susceptibility to mercury toxicity was temperature dependent. Decreasing the temperature increased the toxicity of mercury to cultures of rabbit kidney cells, whereas decreasing temperatures decreased the effect of mercury toxicity on the salmon kidney cells. As a consequence, fish taken from arctic waters are liable to be more toxic when introduced into mammalian food chains. Albumin was shown to act as a protective agent in vitro against inorganic mercury toxicity. Research was supported in part by the University of Victoria Faculty Grant No. 08-869 and a Medical Staff Research and Education Fund Grant from Wayne County General Hospital, Eloise, Michigan.     

Protective effects of selenium against mercury toxicity as studied in the rat liver and kidney by nuclear analytical techniques

Mercuric chloride and sodium selenite were separately administered to male rats in the drinking water or in a combination (2.5 mmol Hg/L and 0.1 mmol Se/L). The mercuric chloride group showed histopathological lesions, as evidenced by cell necrosis in the liver and tubular necrosis in the kidney. The sodium selenite group showed some depression in growth, but pathological changes were found neither in the liver nor in the kidney. Simultaneous administration of both compounds produced a protective effect on weight loss and histopathology. These effects were associated with some small structures in the kidney proximal tubules and to some structure in the extracellular space in the liver. Thin, unstained cryosections were freeze-dried and examined in the Studsvik Nuclear Microprobe. The structures observed in the liver and the kidney were shown to contain both selenium and mercury.     

Long-term performance of bioreactors cleaning mercury-contaminated wastewater and their response to temperature and mercury stress and mechanical perturbation

The long-term performance of bioreactors retaining mercury from contaminated industrial wastewater was analyzed at the laboratory scale, and its response to mechanical perturbations (gas bubbles and shaking) as well as to physical (increased temperature and hydraulic load) and chemical stresses (increased mercury concentration) likely to occur during on site operation was studied. Two packed-bed bioreactors with 80-cm(3) lava chips as biofilm carrier were inoculated with nine Hg(II)-resistant natural isolates of alpha- and gamma-proteobacteria. Chloralkali wastewater containing ionic mercury (3.0 to 9.7 mg/L Hg(2+)), amended with sucrose and yeast extract, flowed through the bioreactors at 160 mL/h. During the 16-month investigation the bioreactors showed no sign of depleted performance in terms of mercury-retaining capacity. After 16 months, both bioreactors still retained 96% of the mercury load. The performance of the bioreactors was sensitive to mechanical perturbations (e.g., sheer forces of gas bubbles). Shifts to higher Hg(2+) inflow concentrations initially decreased the mercury retention efficacy slightly. However, the bioreactors could adapt to Hg(2+) concentrations of up to 7.6 mg/L within several days. Old biofilms were less affected than the younger ones. The performance of the bioreactors was not affected by an increase in temperature up to 41 degrees C and an increased volumetric load (up to 240 mL/h). The bioreactors regained activity spontaneously after the stress had stopped. Recovery could be accelerated by increased nutrient concentration, although this may lead to blocking of the packed bed.     

Accumulation,regulation and toxicity of copper,zinc, lead and mercury in Hyalella azteca

Zinc, lead and mercury accumulation in the amphipod Hyalella azteca increases with increasing exposure to metals. During 10 week chronic toxicity tests, metal accumulated at the highest non-toxic/lowest toxic concentration was 126/136 µg Zn g^–1, 7.1/16 µg Pb g^–1 and 56/90 µg Hg g^–1 dry weight. Concentrations of lead and mercyry in control animals were substantially lower (1.3 µg Pb g^–1 and 0.4 µg Hg g^–1), but concentrations of zinc in controls (74 µg g^–1) were about one half those of the lowest toxic concentration. Copper was completely regulated. Accumulated copper concentrations after 10 weeks exposure to all waterborne copper concentrations resulting in less than 100% mortality were not significantly different from controls (79 µg g^–1). Lead and mercury concentrations in wild H. azteca should be useful indicators of potential toxicity. Zinc accumulation may also be a useful indicator of zinc toxicity, but careful comparison with control or reference animals is necessary because of the small differences between toxic and control concentrations. Copper is not accumulated by H. azteca under chronic exposure conditions and body burdens of field animals cannot be used as an indicator of exposure or potential toxic effects. Short term exposures to copper, however, result in elevated copper concentrations in H. azteca, even at concentrations below those causing chronic toxicity. Short term bioaccumulation studies might, therefore, provide a useful indication of potential chronic copper toxicity.     

Mercury biotransformations and their potential for remediation of mercury contamination

Bacterially mediated ionic mercury reduction to volatile Hg⁰ was shown to play an important role in the geochemical cycling of mercury in a contaminated freshwater pond. This process, and the degradation of methylmercury, could be stimulated to reduce the concentration of methylmercury that is available for accumulation by biota. A study testing the utility of this approach is described.Abbreviations Hg^R inorganic mercury resistance - Org-Hg organomercury - Org-Hg^R organomercury resistance - SRB sulfate reducing bacteria - Methyl-B12 methylcobalamine     

有害赤潮生物球形棕囊藻对卤虫的毒性研究

利用1997年10月和1998年6月分别在广东汕头饶平海域和香港海域分离到的球形棕囊藻,即球形棕囊藻香港株(Phaeocystis globosastrain HK)和球形棕囊藻汕头株(Phaeocystis globosastrain ST),在实验室条件下研究其对四日龄卤虫(Artemia sinica)的急性毒性。结果表明,对数生长期的HK株藻液24h对卤虫LC₅₀约为2.9×10⁵cell·mL^-1。对数期的ST株对卤虫的毒性难以达到半致死浓度,衰亡期的ST株24h对卤虫LC₅₀约为9.89×10⁶cell·mL^-1。在上述浓度下两者半致死时间分别为20.91h和26.62h,而对数生长期的HK株和衰亡期的ST株的培养物过滤液24h对卤虫LC₅₀则分别为7.1×10⁵cell·mL^-1和1.457×10⁷cell·mL^-1,且在该浓度下的半致死时间分别为26.56h和28.02h。实验表明,HK株藻液和滤液的毒性均大于ST株,且藻液的毒性均大于滤液。     

A stereological study of the effects of mercury inhalation on the cerebellum

Mercury in the environment that arises from organic and inorganic sources can cause irreversible damage to the nervous system. Toxicity may be direct or may arise from interactions with other metals in the environment. We evaluated the possible effects of mercury vapor on rat cerebellum. Twelve adult female rats were divided into control and experimental groups. The rats in the experimental group were exposed to mercury vapor for 9 h/day for 45 days. Cerebellar tissue samples were evaluated using stereology and for histopathology. The total number of Purkinje cells was estimated using a physical disector method. We found that in the experimental group, overall volume decreased and the number of Purkinje cells was reduced. We also found cellular damage including pycnotic nuclei, eosinophilic cytoplasm and vacuolization; these features were absent in the control group. We found that chronic exposure to inorganic mercury vapor is toxic to the cerebellum.     

Flow cytometric analysis of the cadmium-exposed green alga Chlamydomonas reinhardtii (Chlorophyceae)

A flow-cytometric method was developed and evaluated as a rapid ecotoxicological tool using cultures of the microalga Chlamydomonas reinhardtii (Chlorophyceae) under cadmium exposure. Three staining protocols were developed to assess the toxicological impact of this trace metal on algal physiology. Algal cells were exposed to total nominal cadmium concentrations of 5 and 100 µM. After 48 and 72 h exposure the fluorescent probes, fluorescein diacetate (FDA), dihydrorhodamine 123 (DHR123) and tetramethylrhodamine methyl ester (TMRM), were used to assess esterase activity, presence of reactive oxygen species and membrane potential, respectively. Results indicated that cell size, cell granularity and internal complexity were influenced by cadmium, confirming earlier findings on ultrastructural changes in microalgae exposed to trace metals. An increase was observed in the percentage of DHR123 positive cells as well as in their mean fluorescence intensity, on increasing cadmium concentration, confirming that this metal exerts its toxicity through the generation of reactive oxygen species. Furthermore, cadmium exposure resulted in an increase in esterase activity, as reflected in fluorescein fluorescence. We suggest this observation was linked to possible detoxification activity and defence mechanisms. Measurements of control samples during protocol optimization for TMRM proved not to be reproducible, leading us to defer any judgment on results of exposed samples and to conclude that TMRM does not seem suitable for flow cytometric use in algae. Our results demonstrate that although very rarely used in ecotoxicology, flow cytometry is a quick and convenient technique to assess toxic effects that can generate mechanistic information on the mode of action of contaminants.     

汞在SPAC-人体系统中的转递及主要影响因素

汞（Hg）是环境中一种具有高度毒性的重金属元素,且具有较高挥发性,因而作为一种全球性的污染物而备受关注。汞在SPAC系统中的迁移转化,是全球汞循环的重要环节,与人类的建康密切相关。汞通过食物链进入人体并在体内蓄积受多种因素影响,主要包括3个方面：土壤性质（如土壤汞含量、pH、有机质、粘土矿物等）,植物特性（植物类型、种类和生育期等）,大气状况（如光照强度、气温和大气湿度等）。此外,锌、硒和抗氧化剂等的存在也有较大影响。综述了汞在SPAC-人体系统中的迁移积累及其调控机理。