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。     

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。     

基于多评估法的硫铁矿区土壤重金属污染特征及源分析

以川南某硫铁矿采选矿区及其尾矿渣场周边农用地为研究对象,采集并测定了51个表层土壤样品、4个背景点土壤样品和4个剖面土壤样品的Cd、Cr、Hg、Ni、Pb、As、Cu、Zn含量,分析其空间分布特征,应用内梅罗综合污染指数法剖析土壤重金属污染现状,并结合相关性分析和正定矩阵因子分析法对土壤重金属来源进行解析。结果表明：研究区土壤Cd、Cr、Hg、Ni、Pb、As、Cu、Zn含量均值分别为2.2、163.0、0.2、66.6、41.8、15.1、80.8、153.0 mg/kg,其中Cd、Cr、Ni、Cu存在不同程度的累积现象,且多个重金属元素之间存在显著相关性;Cd为主要污染元素,Cu具有较强的垂向迁移能力;土壤重金属主要来源为工矿活动源(39.5%)、自然源(37.6%)、大气沉降与交通混合源(22.9%)。川南某硫铁矿周边农用地存在多重金属元素复合污染,其中工矿活动起主导作用。     

地质高背景区铅锌矿废弃地土壤重金属污染评价

调查研究了某废弃铅锌矿区周边农田土壤中重金属Hg、As、Cd、Cr、Pb、Cu、Zn的污染状况,并结合单因素指数法、地累积指数法、污染指数负荷法、灰色聚类法及聚类热图分析对重金属污染程度和空间分布状况进行评价,采用相关性分析和主成分分析识别污染途径。结果表明,研究区Cd、Zn、Hg、Pb、Cu和As含量均超过贵州省土壤背景值。Cd的外源污染最严重,Zn、Pb、Hg次之。重金属污染程度与河流以及距矿区距离呈正相关。主要污染因子为Cd,次要污染因子为Hg和Zn,各采样点均处于严重污染。研究区重金属来源可分为4类,Cu、Cd、Zn属工业源污染,主要为矿山开采;As、Hg污染与工业源和农业源有关;Cr、Pb含量受交通源与工业源以及自然源多方面影响。     

某铜矿区土壤重金属污染评价

分析测试了青海某铜矿区土壤重金属元素(As、Cd、Hg、Pb、Cu、Zn、Cr、Ni)含量,研究了对照区土壤似背景值,采用单因子指数法、内梅罗综合污染指数法、地累积污染指数法评价了矿业活动区土壤重金属污染状况。结果表明,除废石堆场周边区域极个别的土壤样品As、Pb、Cu、Cd元素超标外,矿业活动区土壤环境质量良好;对照区土壤似背景值与青海省土壤元素背景值相当,不是重金属高背景区。     

某铅锌矿区土壤重金属污染分析

分析检测了某铅锌矿区水、土壤、尾矿、废石等样品重金属元素含量,追踪调查了尾矿库、排土场下游土壤重金属污染程度和分布范围,并对重金属元素相关性进行了研究。结果表明:铅锌矿区土壤环境质量总体较差,铅锌矿区重金属污染集中分布在尾矿库和排土场下游地块;铅锌矿区主要污染元素为Cd、Cu、Pb、Zn、As,污染程度以轻度-中度污染为主;尾矿库下游重金属元素Cu、Pb、Zn、As污染分布在1 600m内;排土场重金属污染范围主要集中在下游400m内。土壤样品Cu、Pb、Zn与As、Cd元素呈显著正相关性,Cu、Pb、Zn、As、Cd元素来自同一源头,可能源自尾矿、废石等固体废物;Hg、Cr、Ni元素来自另一源头,与矿业活动无关。     

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。     

某冶炼厂周边农田土壤重金属污染状况分析与评价

采用随机布点的方法采取冶炼厂周边农田土壤样品53个,分析了其中Cd、Cu、As、Pb、Zn的含量及部分样品中重金属的赋存形态,结合国家土壤环境质量标准和内梅罗污染指数法对土样进行分级评价.结果表明,该地区农田土壤受重金属综合污染程度依次为:Cd > As > Cu > Zn > Pb,其中水田土壤受Cd、Cu污染较旱地严重,受As污染略轻于旱地.水旱2种类型土壤中各重金属的形态分布规律相似,其中Cd以弱酸态和可还原态为主,Cu、As、Pb、Zn均以残渣态为主.     

钨矿矿区土壤多种重金属含量及赋存形态研究

以赣州市赣县王母渡镇东埠头钨矿矿区开采区、尾砂库、矿区附近河流沿岸及矿区土壤为研究对象,选择该矿区污染土壤样本21个,采用王水消煮法对土壤样品进行处理,运用等离子体发射光谱仪（ICP-AES）测定土壤样品中Pb、As、Hg、Cr、Cd、Zn、Cu、Ni的含量.选用修正的BCR法测定矿区土壤中重金属元素的赋存形态,结果表明：As、Zn、Cr、Pb、Ni在外界条件影响下可转换为可交换态,矿区中残留选矿剂对重金属赋存形态的影响较大,As、Cd污染较为严重.     

转炉炉壳热应力分析

根据实际转炉建立实体模型。以有限元为手段,考虑了炉衬和炉壳材料的物性参数随温度变化的特点和炉衬与炉壳之间膨胀间隙,计算了转炉炉壳在温度载荷和炉衬膨胀压力同时作用下的热应力。所得结果可为转炉炉壳设计提供依据。     

焦炭热性能指标意义浅析

通过对焦炭在高炉内的历程及其变化规律的剖析,阐述焦炭热性能指标的意义,形象地把焦炭在高炉内的损耗分为三部分(M1,M2,M3)。指出M2对焦比及焦炭价格有一定的指导作用。     

Results of treatment of cancer of the cardia

Cancer of the cardia is traditionally discussed with cardiac cancer of the lower portion of the esophagus and upper gastric cancer invading the esophagus, and the specific characteristics of cancer of the cardia have never been clearly defined. We reviewed the outcome of 172 patients with adenocarcinoma of the cardia who had undergone radical surgery between 1949 and 1994 in the Division of Gastrointestinal Surgery of the Cancer Institute Hospital. The centers of the tumors were located within 2 cm above and below the boundary between the esophagus and the stomach, and their longitudinal diameter was less than 8 cm. We divided the patients into an early period (1949-1979; n = 79) and a late period (1980-1994; n = 93), and focused on the historical transition. There were no differences in patient gender or histology between the two periods. However, the late period was associated with fewer cases of esophageal invasion and shorter longitudinal diameter, as the age of the population advanced. The number of advanced cancers such as the localized and infiltrative type had decreased, and early cancer and early clinical stage had become more common, but despite the fact that the number of early cancers had increased, extended dissection, such as thoracic and paraaortic lymph node dissection, was performed more frequently. By clinical stage, the long-term outcome markedly improved in Stage I patient in the late period, and tended to improve in Stage II and III patients. This appears to have been attributable to the prevention of micrometastasis by extended dissection, although the number of early cancers is another major potential cause. There were no differences in the outcome of Stage IV patients between the two periods, and further advances in multimodality therapy must be awaited. The range of resection is basically proximal gastrectomy, and if there are adequate indications, the prognosis is favorable. In view of the status of lymphatic flow and lymph node metastasis, and long-term results, lateroaortic lymph node dissection is important. Since the number of early cancer patients has been increasing, if intraabdominal recurrence is prevented, intrathoracic lymph node dissection will contribute greatly to the outcome of such patients.     

The effect of amount of possession of the trait of hostility on accuracy of perception of hostility in others.

Some theories of personality hold that an individual's perception of others is influenced by his own personality characteristics; more specifically, that a trait of low social value will be projected more into others, and that insight into the possession of these characteristics reduces this distortion. These 2 hypotheses were tested by having a group of college students rate each other (including themselves) on degree of friendliness or hostility. Agreement with group rating about self yielded the insight score. In general, the hypotheses were supported; the "friendly" Ss were most accurate in their perception of others, and insight was positively associated with accurate perception. From Psyc Abstracts 36:04:4HL16M. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of rates of infection of two methods of emergency ventricular drainage

The rates of infection of two methods of external ventricular drainage in use at Atkinson Morley's Hospital--namely, (a) percutaneous drainage with Rickham reservoirs and (b) tunnelled ventriculostomies--were compared in this retrospective review. Percutaneous drainage of CSF with Rickham reservoirs was associated with a 27% rate of infection as identified by positive microbiological cultures; tunnelled ventriculostomy catheters had a 10% infection rate. The difference in the infection rate between the two methods was statistically significant (P < 0.015). Other variables examined, including the age and sex of the patients and the reasons for ventricular drainage, were not associated with an increased rate of infection. Most infections from either method were caused by a coagulase negative staphylococcus. The average duration of ventricular drainage before identification of positive cultures was 5.7 days for Rickham reservoirs and 6.0 days for ventriculostomies.     

浅析《野草》的版画特征

鲁迅先生一生热爱美术作品,对版画中木刻兴趣尤甚.<野草>作为其"写心之作",亦呈现出一些与木刻版画一致的审美特征:一是具有木刻版画的色彩特征,多对比、多冷色,有阴郁的美感;二是具有木刻版画的力度特征,环境描写、人物刻画处处刀锋毕现,遒劲有力,有一种"力之美".     

四辊破碎机车刀架的改造

针对四辊破碎机车刀架车削中存在的几个问题,详细介绍了电动车刀架的结构和工作原理,建立主要设计参数的数学表达式,并进行适当的分析。改造后,这种电动车刀架运行平稳、可靠、方便、省力,取得了预期的效果。     

Effect of antibiotics of chemotaxis of human leukocytes

The effect of 20 different antibiotics on chemotaxis by human neutrophils was studied. Human leukocytes incubated with chloramphenicol, rifampin, sodium fusidate, and tetracyclines in vitro showed markedly depressed migration. The mechanisms by which these antibiotics affect leukotaxis are discussed.