龙葵修复镉污染土壤的研究进展

近年来土壤镉污染问题日趋严重,对镉污染土壤的治理迫在眉睫。植物修复是净化重金属污染土壤最有潜力的原位修复技术之一,因地制宜地选择植物修复材料是大田植物修复成功实施的关键。本文综述了镉富集植物龙葵(Solanum nigrum)对镉的富集特性及生理响应;揭示了在镉胁迫下,龙葵产生根际螯合作用、区隔化及抗氧化系统的耐镉机制;概括了龙葵与添加剂、农艺措施、微生物联合修复技术等的应用研究;阐明了未来对龙葵的研究侧重点应放在提高龙葵对土壤中镉的固定和吸收方面;研究结果为重金属污染土壤植物修复工作的深入开展提供了参考。     

不同水域中水葫芦对铅、镉、铬、汞的富集规律研究

试验主要研究不同水域的水葫芦(Eichhornia crassipes)对铅、镉、铬、汞的吸收规律。采集浙江金华、绍兴等地8处不同水域的水葫芦样品及水样,采用原子吸收光谱法和原子荧光光谱法测定该4种重金属含量。结果表明:水污染严重区域,水葫芦中重金属含量较高。被调查地区水中铅、镉含量显著高于铬及汞含量(P0.05)。水葫芦根中各重金属含量总体高于茎叶,茎叶中镉的含量显著低于铬的含量(P0.05),而根中镉含量也低于铬但差异不显著(P0.05)。在试验条件下,随着水中铅、镉含量的增加,根与茎叶中相应金属含量有上升趋势。     

重金属污染对免疫功能的影响

金属元素种类很多,通常将比重大于4或5的称之为重金属。如果这么计算,在自然界中的重金属约有60种或45种。这些重金属元素中大部分对动物机体具有明显的毒害作用,尤其是铅、镉、汞等重金属,其毒害作用更为明显。在自然状态下,这些重金属引起机体的机能异常,主要是通过较长时间的慢性作用才实现的,即通过对环境中土质、水质等的污染而实现的。造成环境污染的因素很多,但对于重金属污染且不可忽视。尤其镉、铅、汞等所造成的污染实有增加的趋势。对某些矿厂及冶炼厂的废水、废气处理不当     

汞中毒对动物体内铜,锌,铁重新分配的影响

重金属汞、镉、铅等在环境污染中起着特殊的作用。与有机化合物不同,有毒元素在土壤和水源中不被破坏,而蓄积于环境客体中,并沿着农畜饲料和人类营养品的营养链迁徒。大部分汞化物,尤其是溶解的汞,是最危险的一种重金属。它具有很高的毒性,并有蓄积作用。这种特征的...     

化肥对土壤的污染及防治对策

1化肥对土壤环境污染表现 1．1重金属和有毒元素有所增加,危害人体健康 产生污染的重金属主要有锌、铜、钴和铬。从化肥的原料开采到加工生产,会带进一些重金属元素或有毒物质,其中以磷肥为主。目前我国施用的化肥中,磷肥约占20％,磷肥的生产原料为磷矿石,含有大量有害元素氟和砷。同时磷矿石的加工过程还会带进其他重金属镉、汞、砷、氟,特别是镉。     

环洪泽湖农田土壤重金属污染现状及修复对策研究

为了研究环洪泽湖地区农田土壤重金属污染状况,试验采用常规方法测定了农田土壤环境中汞、镉、铅、铬、砷等重金属含量。结果表明:环洪泽湖地区农田土壤中重金属汞和镉重度污染,其中汞含量较高的是泗洪县和洪泽县农田,泗阳县和盱眙县次之,淮阴区最低;泗阳、泗洪县农田土壤中镉含量较高,洪泽、盱眙县次之,淮阴区含量最低。     

家禽饲料中重金属和微生物污染的危害及防治

<正>重金属和微生物通过污染家禽饲料而影响家禽产品进而危害人体健康已经成为食品安全关注的焦点。重金属,如铅、镉、汞和铬等在少量甚至微量下就可引起家禽明显的毒性作用。同时,重金属由于难以被家禽机体分解代谢和易蓄积等特性通过食物链最终会对人体造成危害。     

伊犁地区肉牛产业链中土壤、饲料及牛肉中重金属残留分析

为了解新疆伊犁地区肉牛产业链中重金素元素的残留情况,本研究采用原子吸收法对新疆伊犁地区肉牛养殖场的土壤、饲料及屠宰场的牛肉进行重金属砷、铅、汞、铬、镉的检测。结果表明土壤样品中重金属铅、砷、汞、铬、镉元素含量分别为0.03~0.20、3.87~8.30、0.15~0.23、0.09~0.48和0.41~0.86 mg/kg。饲料样品中铅、砷、汞、铬、镉元素含量分别为3.01~18.09、75.35~94.27、19.65~24.37、0.06~1.04和1.81~8.46 μg/kg。牛肉中铅、砷、汞、铬、镉元素含量分别为0.23~0.54、1.22~7.12、0.28~0.53、0.01~0.27及0.02~0.03 μg/kg。土壤和饲料、饲料和牛肉、土壤和牛肉中重金素含量的相关系数分别是0.96、0.99、0.98。综上所述,伊犁地区肉牛养殖场的土壤和饲料,屠宰场的牛肉中重金素铅、砷、汞、铬、镉元素的含量均没有超标,三者中重金属含量具有较高的相关性。     

哈茨木霉的耐镉性及其对狗牙根耐镉能力的影响

为明确耐镉微生物的生物学特性及其对植物耐镉性的影响,并为微生物-植物联合修复重金属污染土壤提供参考,以从湖南株洲清水塘化工厂重金属污染土壤样品筛选鉴定出来的一株耐镉性较强的真菌-哈茨木霉（Trichoderma harzianum）为试验材料,研究了其基本生物学特性和对镉胁迫下狗牙根（Cynodon dactylon）生长与生理的影响。结果表明：哈茨木霉生长的适宜pH约为7,最大生长量的培养时间约为72 h;哈茨木霉对镉离子的吸附率在镉浓度为100 mg·L^-1时最高,达到63.54%;在镉浓度为0~300 mg·L^-1条件下,哈茨木霉对镉离子的吸附方式主要为细胞壁吸附;在不同镉浓度下,哈茨木霉均能产生吲哚乙酸（Indole-3-acetic acid,IAA）;正常培养条件下（镉浓度为0 mg·L^-1时）,哈茨木霉产IAA量为30.88 μmol·L^-1,镉浓度为300 mg·L^-1时,产IAA量为10.46 μmol·L^-1;外源添加哈茨木霉能有效缓解镉胁迫对狗牙根根长的抑制、降低丙二醛（Malondialdehyde,MDA）含量,并有效促进狗牙根对镉离子的吸收。本试验研究结果不仅为镉污染土壤的微生物修复提供重要菌株,同时提供了一种高效的微生物-植物联合修复重金属污染土壤的途径。     

草本能源植物修复重金属污染土壤的潜力

在北京郊区重金属轻度污染土地开展了柳枝稷、荻、芦竹、杂交狼尾草四种草本能源植物的规模化种植,分析其对砷、汞、铜、铬、铅、镉等六种重金属的富集能力与修复潜力。结果表明,四种草本能源植物均属于非超积累植物,但柳枝稷、荻、芦竹、杂交狼尾草的生物质产量较高,分别为23.23t.hm-2、28.22t.hm-2、47.08t.hm-2、59.22t.hm-2,且不受重金属轻度污染的明显负面影响,因此其重金属绝对富集量可观。杂交狼尾草对砷、汞、铜、铅、镉的绝对富集量分别为23.12g.hm-2、0.35g.hm-2、1132.62g.hm-2、95.18g.hm-2、6.07g.hm-2,芦竹对铬的绝对富集量达到1333.37g.hm-2。草本能源植物对重金属污染土壤具有一定的修复潜力,并以杂交狼尾草最大,芦竹、荻、柳枝稷次之。     

Determination of the immunotoxic potential of heavy metals on the functional activity of bottlenose dolphin leukocytes in vitro

Heavy metals may affect the immune system of cetaceans. But no information exists on their effects on the bottlenose dolphin (Tursiops truncatus) immune system, although this species is a coastal top predator which can bioaccumulate high concentrations of them. This work studies the effects of Hg (1, 5 and 10mg/L), Al (2,5, 25 and 50mg/L), Cd (1, 10, 20 and 40mg/L), Pb (1, 10, 20 and 50mg/L) and Cr (1 and 10mg/L), on the function of phagocytes and lymphocytes isolated from the peripheral blood of bottlenose dolphins under in vitro conditions. Cell viability, apoptosis, lymphocyte proliferation and phagocytosis were evaluated. Viability and lymphoproliferation were measured with Alamar Blue assay, and apoptosis and phagocytosis were evaluated with flow cytometry. Apoptosis was detected as mechanism of cell death after cadmium and mercury exposure. A significant reduction in the lymphoproliferative response was registered by exposure to 1mg/L of mercury, 10mg/L of cadmium and 50mg/L of lead. Decreased phagocytosis was also observed at 5mg/L of mercury, 50mg/L of aluminium and 10mg/L of cadmium. Chromium did not present any effects on any immune assay at the concentrations tested. The concentrations of heavy metals that were found to affect the functional activity of bottlenose dolphin leukocytes are within the environmental ranges reported in the tissues of bottlenose dolphins. These results support the hypothesis that exposure to these contaminants, particularly mercury and cadmium could lead to a reduction in host resistance to disease in these animals.     

Heavy metals (cadmium, copper, lead and mercury) in common eiders (Somateria mollissima) from Denmark

In an examination of 50 Danish common eiders, the liver and kidney content of cadmium, copper, lead and mercury was determined. Eiders were chosen for analysis, because this species feed almost exclusively on the common mussel (Mytilus edulis), which is known to accumulate heavy metals. The concentrations recorded of cadmium, copper, and mercury were lower than what is usually regarded as toxic for birds, except for one eider which carried more than 2000 mg copper/kg liver tissue (dry weight). Of the 42 eiders analysed for lead, four had toxic levels, i.e., more than 7 mg per kg liver wet weight, and two other had increased levels, i.e., 3-7 mg lead per kg liver wet weight. The mean Cd concentration was 3.3 mg/kg liver (ww). This means that by consumption of ab. 160 gram liver from the common eider, the weekly tolerable intake of cadmium suggested by FAO/WHO would be exceeded.     

Heavy metal, polychlorinated biphenyl and organochlorine pesticide residues in marine organisms: risk evaluation for consumers

This survey provides information on the levels of heavy metal, polychlorinated biphenyl and organochlorine pesticide residues in marine organisms to ascertain whether these concentrations exceeded the prescribed legal limits. In order to assess the potential human health impact, the weekly intake was estimated. Most of the organisms analysed showed higher levels of mercury than the maximum permissible limit, while cadmium and lead were below the proposed permissible limits in all samples. The estimated intake was far above the established Provisional Tolerable Weekly Intake for all metals, except for total mercury.     

Heavy Metal,Polychlorinated Biphenyl and Organochlorine Pesticide Residues in Marine Organisms: Risk Evaluation for Consumers

This survey provides information on the levels of heavy metal, polychlorinated biphenyl and organochlorine pesticide residues in marine organisms to ascertain whether these concentrations exceeded the prescribed legal limits. In order to assess the potential human health impact, the weekly intake was estimated. Most of the organisms analysed showed higher levels of mercury than the maximum permissible limit, while cadmium and lead were below the proposed permissible limits in all samples. The estimated intake was far above the established Provisional Tolerable Weekly Intake for all metals, except for total mercury.

     

Role of the Food and Drug Administration concerning chemical contaminants in animal feeds.

Chemical contamination of animal feeds and feed ingredients is of concern to the Food and Drug Administration. Contamination by industrial chemicals such as polychlorinated biphenyls and polybrominated biphenyls; heavy metals such as lead, cadmium, and mercury; and pesticides such as dieldrin and chlordane exemplify the problem in feeds and the resulting problem of tissue residues in human foods.     

Mortality factors, environmental contaminants, and parasites of white-tailed sea eagles from Greenland

Twelve white-tailed sea eagles (Haliaeetus albicilla groenlandicus) found dead between 1997 and 2000 in Greenland were examined to investigate the health status, including the causes of death and the burden of organochlorine contaminants and potentially toxic heavy metals. The determined causes of death were unspecific trauma (n = 6), lead poisoning (n = 2) with 36 and 26 ppm lead in the liver tissue, infectious diseases (n = 1), injuries sustained during intraspecific conflict (n = 1), and gunshot (n = 1). One lead poisoned eagle had a single lead shot pellet in its gizzard. No diagnosis could be made in one case because of decomposition of the carcass. Four of the investigated eagles were injured with lead shot or bullet fragments; one of the birds was killed with about 69 lead shots. Levels of organochlorine pesticides, polychlorinated biphenyls, mercury, and cadmium in organs were moderate. The parasite fauna consisted of one coccidian and three helminth species. The acanthocephalas Profiliocollis botulus and Corynosoma suduche as well as the nematode Stegophorus stellaepolaris are all new records for the white-tailed sea eagle.     

重金属元素在家蚕体内累积及其对家蚕细胞(BmN)的急性损伤

利用不同浓度的CACl2溶液对培养的家蚕细胞(BmN)进行诱导,结果表明,随CACl2浓度的改变,其细胞形态发生了相应的变 化,死亡率与浓度具有一定量效关系;对4龄起家蚕(菁松,原种)添食不同浓度的CACl2、Pb(NO3)2,结果显示,Ca2+、Pb2+具抑制其生长,影响其 茧质的不良影响,耐重金属能力差于皓月原种。     

污染指数及危害系数(HQ)评价生乳中重金属残留风险分析方法研究

本研究建立了应用单项污染指数及内梅罗综合污染指数法评价生乳中重金属的污染情况的方法,以分析不同地区的污染情况;并且对于生乳中低浓度的重金属残留及没有残留限量的重金属残留,以慢性非致癌性风险HQ值进行描述,与参考剂量相比较,进而确定其对于成人饮用的安全性。对中国2个奶业主产区的20个生乳中的砷、铅、铬、汞、铝、镍进行了污染分析及危害描述,证明了本方法的合理性和适用性。     

Effects on interferon of heavy metal excess and zinc deficiency.

Near toxic concentrations of cadmium sulfate, mercuric chloride, and nickel sulfate reduced interferon action in tissue cultures, but increased intake by the intact mouse of lead acetate and mercuric chloride did not reduce interferon action. Lead and nickel given orally inhibited the protective activity of Newcastle disease virus against encephalomyocarditis virus-induced mortality, whereas cadmium, mercury, cobalt sulfate, and sodium arsenite given orally and deficiency of zinc did not influence this action. Excess lead and cobalt and deficiency of zinc, but not excess cadmium, mercury, or nickel, inhibited the protective activity of poly I/poly C against encephalomyocarditis virus-induced mortality. These results illustrate the various actions of increased concentrations of certain metals or a deficiency of zinc on interferon action or on actions of interferon inducers.