湖南某铅锌矿区土壤重金属污染及潜在生态风险评价

在湖南郴州某铅锌矿区采集94个表层土样,分析土壤中As、Cd、Pb、Zn的含量及污染程度,并运用hakanson指数法对其进行潜在生态风险评价。结果表明,土壤中As、Cd、Pb、zn的平均含量分别为89．73mg／kg、7．69mg／kg、876．83mg／kg和1018．83mg／kg,均超过国家土壤环境质量三级标准的限定值,其平均污染指数分别为：2．24、7．69、1．75、2．04。研究区综合污染指数为13．76,污染程度为较高污染。土壤重金属元素的潜在生态危害性为Cd〉As〉Pb〉Zn,其中Cd是主要的生态风险的贡献因子。     

海南岛西部地区砖红壤中重金属分布特征及潜在生态风险评价

[目的]对海南岛西部地区砖红壤中重金属元素进行生态地球化学调查和生态风险评价.[方法]时海南岛西部地区砖红壤中的Cr、Cu、Zn、As、Cd、Pb 6种重金属的含量进行分析,并用单因子指数法和Hakanson生态风险指数法评价了砖红壤中重金属综合污染效应.[结果]海南岛西部地区砖红壤中Cr、Cu、Zn、As、Cd、Pb的平均含量分别为65.57、35.16、93.56、8.50、0.24、79.29 mg/kg.其中主要的重金属污染因子是Pb.各金属影响因子的顺序为Pb>Cu=Zn>Cr>As>Cd;各种重金属的潜在生态危害系数大小顺序为Pb>Cd>Cu>As>Cr>Zn;潜在生态风险指数(RI)平均值为45.14,属于低生态危害范畴.[结论]海南岛西部地区砖红壤中重金属污染属于轻微污染.     

有色金属矿区土壤Pb、Zn、Cd污染评价及形态分布研究

以郴州废弃矿区土壤为研究对象,对矿区所采集的12个土壤样品进行重金属含量调查及综合污染程度分析,并采用地累积指数法对重金属污染程度进行评价.结果表明,土样中重金属Pb、Zn、Cd的平均含量分别为:3 149.36 mg/kg、3 848.75 mg/kg、26.74 mg/kg.Zn和Cd达到极严重污染程度,Pb达到强污染严重水平.采用BCR连续提取法对土壤中Pb、Zn、Cd三种重金属元素的形态进行分析,结果表明Pb主要以可还原态存在,Zn主要以残渣态存在,Cd主要以弱酸提取态存在.     

贵州丹寨县铅锌矿区小流域土壤重金属污染特征及生态风险评价

为探究贵州丹寨县铅锌矿区矿业活动对土壤系统运转对环境影响,以丹寨县兴仁镇铅锌矿区土壤为研究对象,采集小流域内河流周边不同土地利用类型土壤表层(0~20cm)的样品,分析测定土壤中Cu、Cd、Pb、Zn、Mn、Hg、As 7种重金属含量。应用单因子污染指数法、内梅罗综合污染指数法、地质累积指数法、潜在生态指数法对矿区不同土壤层重金属进行污染程度和潜在生态风险进行评价。结果表明,0~10cm土壤中Cu、Cd、Pb、Zn、Mn、Hg、As含量分别是贵州省土壤背景值的0.65、5.13、1.74、2.45、0.59、5.08、0.27倍。10~20cm土壤中Cu、Cd、Pb、Zn、Mn、Hg、As含量分别是贵州省土壤背景值的0.71、3.11、1.18、2.21、0.65、4.88、0.21倍。不同小流域与不同深度土层危害程度有所差异,通过评价结果得出研究区主要污染重金属元素为Cd、Hg,土壤重金属处于中等及以上潜在生态危害程度。     

典型冶炼企业集中区土壤重金属污染分析及风险评价

以南方典型有色金属冶炼企业集中区为研究对象,对冶炼企业厂界内表层土壤中Cd、Pb、As、Zn、Hg、Cu、Cr（Ⅵ）、Ni八种元素含量进行测定分析,利用单因子污染指数法、内梅罗污染指数法、潜在生态风险和健康风险模型对冶炼厂的生产区、储存区、废水治理区、固废贮存区或处置区进行重金属污染评价及风险评价。结果表明,冶炼厂内土壤受到Cd、Pb、As、Zn四种元素不同程度的污染;风险评价结果显示,冶炼厂内土壤总体存在强潜在生态风险,Cd、As、Zn是主要生态危害元素;同时As存在非致癌风险和致癌风险,Pb存在非致癌风险;厂内污染主要集中在生产区和废水治理区。     

铬渣堆场周边土壤中重金属污染及风险评估

以铬渣堆场周边土壤为研究对象,分层分区采集土壤样品,采用地累积指数、潜在生态风险指数法和人体健康风险评价模型,对土壤中Cr(VI)、Cr、Pb、As等重金属进行风险评估。结果表明,土壤中Cr(VI)、Cr、Pb、As含量的平均值分别为567.19、9 055.61、457.19、66.80mg/kg。研究区土壤均处于中度偏强的生态风险等级,且铬污染受人为污染影响严重。研究区土壤中的Cr(VI)和As存在致癌风险,主要是经手—口摄入途径暴露所致。研究区土壤的非致癌风险非常严重,且主要贡献来源于铬元素。     

湖南某冶炼区果园土壤Cd、Pb、Zn分布及生物可利用性评价

对湖南某废弃铅锌冶炼厂周边土壤的现场调查和取样分析,发现研究区土壤pH值范围为4.5~6.5。土壤中Cd、Pb、Zn平均含量分别为5.66 mg/kg、2 409.00 mg/kg、1 224.42 mg/kg,污染显著,且变异强度较大。风险评估编码方法(RAC)显示研究区土壤中Zn处于低风险及以下;Pb含量不均匀,污染最重者达到极高风险;Cd绝大部分处于中风险及以上。桔子样品中重金属含量的检测结果表明,Cd未超过《食品中污染物限量》标准;Pb富集程度最高,其含量最低的样品Pb含量为标准的4倍以上。     

某铅锌尾矿库周边土壤重金属污染特征及其来源分析

以某铅锌尾矿库周边土壤为研究对象,测定土壤中Cd、Hg、As、Pb、Cr、Cu、Zn、Ni重金属含量,采用地质统计分析掌握重金属含量空间分布,再利用单因子污染指数、内梅罗综合污染指数和地质累积指数评价重金属污染状况,并结合相关性分析和主成分分析探重金属来源。结果表明,土壤中Cd、Hg、As、Pb、Cr、Cu、Zn、Ni平均含量分别为10.4、1.54、132、653、62.8、73.8、1 392、31.6 mg/kg,越靠近尾矿库,Cd、As、Pb、Cu、Zn、Hg含量越高。内梅罗综合污染指数表明,研究区综合污染指数为11.2,为重污染,单因子污染指数和地质累积指数表明,研究区土壤Cd污染最严重,其次是As、Zn、Pb、Cu、Hg污染,Cr和Ni无污染。相关性分析和主成分分析表明,Cd、Hg、As、Pb、Zn之间存在显著正相关关系,主要受铅锌尾矿库长期堆存、转运及加工等人为活动影响,Cr、Ni主要来自土壤母质,Cu主要受矿业活动和农业活动共同影响。     

某退役稀土回收厂表层土壤重金属污染及其对人体健康风险评价

为查明某退役稀土回收厂表层土壤重金属污染及其对人体健康的风险,在厂区内布设8处土壤采样点,共采集表层土壤样品24份,检测土壤中重金属含量,采用单因子指数法和内梅罗指数法对土壤污染情况进行评价,并对该场地进行人体健康风险评估。结果表明：土壤样品中Cu、Zn、Pb、Cd、Cr、As、Hg、Ni 8种重金属元素的最大浓度分别为56、145、108.20、3.96、64、17.40、0.21、25 mg/kg,均高于研究区土壤环境背景值。其中部分监测点Cu、Pb、Cd浓度高于《土壤环境质量标准 农用地土壤污染风险管控标准》（GB 15618—2018）筛选值标准,集中在储罐区、窑炉、污水处理站、渣堆场附近,铜超标倍数较小,镉最大超标数12.2倍,在储罐区附近。单因子指数法研究表明,Zn、Cr、As、Hg、Ni处于未污染水平,Cu、Pb处于未污染到轻微污染水平,Cd处于未污染到重度污染水平。运用土壤健康风险评价体系中的吸食、皮肤接触、呼吸接触3种暴露因素对人体健康风险的评估表明：Cd、Cr、As存在致癌风险,Pb、Cr、As存在非致癌风险。源解析分析结果表明,研究区土壤中Cu、Zn、Cr、As、Pb有相同或相似的来源,主要来自于储罐的泄漏、污水处理站泄漏、渣堆场淋溶水渗流及扬尘。     

巩义煤矿区周边土壤重金属积累特征研究

测定了巩义某煤矿区周边区域土壤中的重金属含量,并运用单因子污染指数、内梅罗综合指数及地质累计指数评价了该区域重金属污染特征。结果表明,该地土壤已出现多种重金属元素不同程度的累积,Cr,Ni,Cu,Zn,Cd,Pb和As的平均依次分别为59.9,32.23,31.46,99.29,0.32,113.14和8.23 mg/kg。单因子污染指数表明,7种元素单因子污染指数分别为0.95,1.18,1.57,1.59,1.60,5.07和0.84,Pb属重度污染,Ni,Cu,Zn和Cd属轻污染,As,Cr属安全水平。内梅罗综合指数指出,该区域土壤均存在不同程度的重金属污染,84%的采样点处于重污染水平。地质累计指数表明,该区域Pb平均级别属偏中污染,Zn,Cu平均级别均属轻污染,Cd,Ni,Cr和As元素平均级别均属无污染。     

Research and teaching in social and preventive medicine and in public health

Both public health and social and preventive medicine are characterised by the common goal of promoting, maintaining and improving health and preventing disease, and both are concerned with a population-related, preventive and environmental perspective. But whereas public health is interdisciplinary and goes far beyond the medical focus, social and preventive medicine is medically based and forms a bridge between public health and medical practice. Research in a department of social and preventive medicine serves to support preventive and medico-social activities in medical practice as well as in public health. This is illustrated by results from research conducted at the author's department during the last twenty years. Examples are research in support of smoking cessation activities, and research used for the planning of care for the elderly. Both the research and the teaching activities of the department take into account the population focus of public health as well as the focus on individual medicine in clinical practice.     

Identification and changes in prejudice and in authoritarianism.

Ss "were first given the F Scale and a measure of anti-Negro prejudice… . Four weeks later they read a case history of a person who was prejudiced and authoritarian. Half of the subjects were told that the person in the case history was similar to themselves in background and objective personal characteristics. The other half… that the person was dissimilar to them. Three weeks later the F Scale and the anti-Negro prejudice scale were readministered. It was found that those low in prejudice at the first administration became more prejudiced but only if they were told the case history was about someone like themselves… . These results were interpreted in terms of the social support for suppressed 'wrong' feelings and in terms of the pressures to achieve cognitive consistency in one's self-concept." From Psyc Abstracts 36:04:4GD65S. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

MPD and DNA bending in crystals and in solution

Bending of 15 to 24 degrees is observed within crystal structures of B-DNA duplexes, is strongly sequence-dependent, and exhibits no correlation with the concentration of MPD (2-methyl-2,4-pentanediol) in the crystallizing solution. Two types of bends are observed: facultative bends or flexible hinges at junctions between regions of G.C and A.T base-pairs, and a persistent and almost obligatory bend at the center of the sequence R-G-C-Y. Only A-tracts are characteristically straight and unbent in every crystal structure examined to date. A detailed examination of normal vector plots for individual strands of a double helix provides an explanation, in terms of the stacking properties of guanine and adenine bases. The effect of high MPD concentrations, in both solution and crystal, is to decrease local bending somewhat without removing it altogether. MPD gel retardation experiments provide no basis for choosing among the three models that seek to explain macroscopic curvature of DNA by means of microscopic bending: junction being, bent A-tracts, or bent general -sequence DNA. Crystallographic data on the straightness of A-tracts, the bendability of non-A sequences, and the identity of inclination angles in A-tract and non-A-tracts B-DNA support only the general-sequence bending model. The pre-melting transition observed in A-tract DNA probably represents a relaxation of stiff adenine stacks to a flexible conformation more typical of general-sequence DNA.     

Cholestatriene and ergostatetraene as in vivo and in vitro membrane and lipoprotein probes

The fluorescent cholesterol analogues, cholesta-5,7,9(11)triene-3-beta-ol (I) and ergosta-5,7,9(11)-22-tetraene-3-beta-ol (II), have been shown to be readily incorporated by various tissues and lipoproteins in rabbits maintained on diets supplemented with these fluorophores. Human erythrocytes and lipoproteins were also found to incorporate I and II in vitro under physiological conditions. The thermotropic behavior of the lipoproteins and erythrocyte membranes labeled with sterols I and II was evaluated using temperature-dependent fluorescence polarization and/or fluorescence intensity spectra. Erythrocyte ghosts, fluorescently labeled in vivo (rabbit) or in vitro (rabbit and human), were found to undergo a reversible thermally induced transition at 24 +/- 2 degrees C. A similar transition occurring at higher temperatures was also observed in fluorescently labeled human and rabbit LDL particles. Furthermore, the transition temperatures and relative microviscosities of the in vivo labeled rabbit LDL particles were found to be dependent upon the amount of sterol present in the rabbits' diet. No evidence of a similar thermotropic transition was observed in any of the HDL particles. These results are discussed in terms of a thermotropic reordering of cholesterol clusters existing in the erythrocyte membrane and of the cholesteryl ester core present within the low density lipoprotein particle.     

Protein phosphorylation and taurine biosynthesis in vivo and in vitro

Taurine is known to be involved in many important physiological functions. Here we report that both in vivo and in vitro the taurine-synthesizing enzyme in the brain, namely cysteine sulfinic acid decarboxylase (CSAD), is activated when phosphorylated and inhibited when dephosphorylated. Furthermore, protein kinase C and protein phosphatase 2C have been identified as the enzymes responsible for phosphorylation and dephosphorylation of CSAD, respectively. In addition, the effect of neuronal depolarization on CSAD activity and 32P incorporation into CSAD in neuronal cultures is also included. A model to link neuronal excitation and CSAD activation by a Ca2+-dependent protein kinase is proposed.     

Differences and similarities in adjuvant chemotherapy in mouse and man

Supernatants obtained after incubation of tumor patient lymphocytes with the homologous tumor-associated antigen (TAA) elicit adherence inhibition in normal guinea pig peritoneal cells. From 37 tested patients with different carcinomas, the supernatants of 30 caused more than 10 per cent adherence inhibition (breast cancer 11/11, lung cancer 7/8, colon cancer 6/7, stomach cancer 6/11). Besides 40 healthy blood donors were tested to a panel of TAA. There was a reactivity more than 10 per cent only in 2 cases. The supernatants of 14 patients with nonmalignant disorders produced adherence inhibition more than 10 per cent in 2 cases. By incubation of tumor patient lymphocytes with the human encephalitogenic protein the supernatants of 19/27 patients elicited a positive reaction. The results suggest that anti-tumor immunity can be detected in an indirect heterologous adherence inhibition system.     

Interaction in systems Wc-Ni-Al and Wc-NiTi in sintering and impregnation

Translated from Poroshkovaya Metallurgiya, No. 5(317), pp. 77–80, May, 1989.     

Chemo- and baroresponses differ in African-Americans and Caucasians in sleep

To determine sleep effects on baro- and ventilatory responses to transient chemo- and barostimulation in African-Americans and Caucasians, 26 nonobese normotensive young subjects (13 African-Americans and 13 Caucasians) were studied awake and in non-rapid-eye movement (NREM) and rapid-eye-movement sleep during induced transient hypoxemia (N2), hypertension (phenylephrine, PE), and concomitant hypoxemia and hypertension (N2 + PE). Arterial blood pressure was recorded by plethysmographic volume clamp, minute ventilation by pneumotachograph, and arterial O2 saturation by pulse oximeter. For all subjects, chronotropic baroresponse (Deltapulse interval/Deltasystolic blood pressure, where Delta is change) increased with NREM sleep (P = 0.007). Baroresponse slope was greater in Caucasians than in African-Americans (ANOVA, P = 0.02). Hypoxemic ventilatory response (Deltaminute ventilation/Deltaarterial O2 saturation) was greater in African-Americans than in Caucasians in NREM sleep (P = 0.01), as was hypoxemic attenuation of baroresponse (N2 + PE, P = 0.03). These data suggest sleep-related differences in arterial chemo- and baroreceptor responses in normal young African-Americans and Caucasians, which may have implications concerning development of systemic hypertension.     

Photoreactivation in bacteria and in skin

In many procaryotic and eucaryotic cells, photoreactivating enzyme mediates light-dependent repair of UV-induced damage: the enzyme binds to a pyrimidine dimer in DNA, and, on absorption of a photon (300-600 nm), specifically monomerizes the dimer, thus repairing the DNA. Photoreactivating enzyme has been found in human tissues and human cells in culture; human cells in culture can photoreactivate cellular dimers, and can mediate photoreactivation of Herpes (human fibroblasts) and Epstein-Barr virus (human leukocytes). Measurements of pyrimidine dimer formation and repair in human skin indicate that detectable numbers of dimers are formed at 1 minimal erythemal dose, that the dimers are rapidly removed in skin kept in the absence of light, and they are more rapidly removed when the skin is exposed to visible light.