Speciation analysis and significance of ecological geochemistry     

Yaping WANG Chunxue XU Ziyi AN Suming WANG 《中国地球化学学报》2006,25(B08):205-205

Different species of one element have different activities, so it has different effects on environment and human health. To analyze qualitatively and quantitatively the speciation of a special element in sample, which is the important basis for appraising the toxicity and studying the rule of transfer and translation of elements. Since the 1970＇s, the scheme of sequential extraction has already been used at many laboratories both at home and abroard, to get the information about heavy metals＇ activity in polluted soils. Because this method has the experimental nature, many schemes of problem has taken place, the absence of consistency of these sequential extraction have been formed. Thus the complexity of the schemes, the lack of selectivity of reagent, the lack of quality control, the result mainly related to the extraction scheme used, and so on. In the face of these problems, the study of experimental methods of sequential extraction on three different soils, sediment in Dongting Lake, soil in Jiangsu Province and loess in Shanxi Province was made. Reference materials of heavy metal speciation following sequential extraction in soil and sediment had been developed. Nowadays two kinds of sequential extraction methods which are widely used are BCR （three steps） and improved Tessier methods （seven steps）. Based on three steps of BCR, water-soluble speciation and the residual speciation were increased in our research. BCR701 was determined eight times at different laboratories using BCR three steps. The results showed that determined data obtained eight times were identical to the standard value, and it is indicated that this method has good reproducibility. The stability and homogeneity experiments indicated that the preparation of three types of candidates accorded with our requirements. Eight laboratories had afforded the determined values of 12 heavy metal elements （Cu, Pb, Zn, Mn, Co, Ni, Cd, Cr, Mo, As, Sb, Hg, Se et al.） using BCR three steps. Also, these three candidates afforded the determined values by seven steps, and 12 laboratories had participated.  相似文献   

Methylmercury and human biomarkers： Questioning the evidence     

《中国地球化学学报》2006,25(B08):239-239

Methylmercury （MeHg） is a powerful neurotoxicant in humans. In terms of biomarkers of MeHg exposure, hair and blood have long been used in epidemiological studies as the biomarkers of choice. In fact, total hair mercury （Hg） content as well as organic blood Hg concentrations reflects exposure to organic Hg from food consumption. Extensive studies, establishing a constant and linear relation between MeHg intake versus Hg levels in hair and blood, were conducted by governmental officials to establish guidelines on safe levels of MeHg exposure, which were translated into threshold daily fish consumption rates （usually expressed as μg MeHg per kg bodyweight）. Nowadays, in most epidemiologic studies blood or hair mercury （Hg） level is commonly used as a valid proxy to estimate human exposure to methylmercury （MeHg） through fish consumption without relating this signal to actual fish consumption patterns among populations. Human variability in mercury toxicokinetics was identified and measurement error has been pointed out to be a substantial contributor to observed variability, particularly where dietary information is retrospective and self-reported. However, experimental evidence indicates that significant variability among individuals may exist in the biokinetics of mercury. Also recent findings from previous population-based studies through COMERN initiative also revealed that MeHg metabolic processes might greatly vary across populations. In fact, it is unlikely that the magnitude of the difference measured between observed and expected levels of mercury, given the reported intake, can be entirely explained by laboratory measurement errors or reporting bias.  相似文献   

Study on Kailyard soil amendment by adding compost of sludge     

Shaoqi ZHOU Weidong LU 《中国地球化学学报》2006,25(B08):252-253

Mixture of municipal sewage sludge and organic garbage, which was alternatively treated by aerobic and anaerobic composting technologies for 60 days. The characteristics of the compost are as follows： the total nitrogen （TN）, total phosphors （TP） and total potassium （TK） are 1.40%, 0.101% and 1908.32 mg/kg on dry weight basis, the contents of Cu, Ni, Cd, Cr, Pb and Zn are 131.23, 21.49, 1.31, 35.49, 72.50 and 616.76 mg/kg on dry weight basis. A basin-scale experiment was carded out by planting watercress with kailyard soil fertilizing with the compost, the results showed that the municipal sewage sludge and organic garbage compost could promote the production of watercress to different degrees, the crop biomass increased from 74.46% to 312.00% with the amount of compost fertilizing on the kaliyard soil while the amount of compost fertilizing on the kaliyard soil below 150 g per 3.75 kg kaliyard soil and decreased from 312.00% to 102.29% while the amount of compost fertilizing on it over 150 g per 3.75 kg kaliyard soil, so the optimal addition of compost in the watercress and soil was 150 g compost per 3.75 kg kailyard soil. Furthermore,  相似文献   

Influence of humic acid on bioavailability of heavy metals in sediments     

Wenhong FAN Jun CHEN 《中国地球化学学报》2006,25(B08):261-261

The mimetic ocean environment and chemical method were used to research the bioavailability effect of humic acid on five heavy metals in sediment, including Cd, Cu, Zn, Pb and Ni. The sediment was separated into four containers with artificial seawater, and each of them had different concentrations of humic acid. The values of concentrations covered the whole range found in natural sediment （0.1%-10%）. According to the 48 hours LC50 of clam and distribution coefficient, metals were added in artificial seawater, and their speciation was determined at first and then after two days＇ incubation. It was found the bioavailability of heavy metals was reduced in the presence of humic acid. The obvious negative effect on Zn was observed, but the influence on Cd was not remarkable. In addition, the contents of Pb and Ni increased obviously in organic phase, and they are correlative with the concentrations of humic acid.  相似文献   

《生物地理学》实践教学改革与大学生创新能力培养     

衣华鹏 《福建地理》2006,21(2):132-134

当前,社会对人才创新能力与实践能力的要求越来越高,如何培养高素质创新能力的人才已成为检验高等教育的重要标志。本文探讨了将“自主、探究与合作的学习方式”运用于《生物地理学》实践教学,激发学生的创新思维,学习科学研究的方法,发展综合运用知识的能力,培养创新能力。  相似文献   

桂北地区早石炭世杜内期的长身贝类的发现及其生物古地理意义     

王海涛  孙元林  陆济璞 《古地理学报》2006,8(4):439-550

在广西北部兴安县高尚镇金子山剖面下石炭统鹿寨组底部，新发现了长身贝类腕足化石，包括1新种、1个相似种、6个未定种和2个属种未定类型。这些长身贝类以Productellidae和Productidae科的分子为主，另有少量Echinoconchidae和Monticuliferidae科的分子。这些长身贝类全部属于生活在静水环境中的薄壳类型，无一与华南同期地层中已知类型相同。它们之间的差异可能反映了不同沉积环境条件对腕足动物群属种的控制。在鹿寨组底部发现的长身贝类以及近年在桂林南边村和黔南睦化剖面腕足动物群的发现显示出华南台缘斜坡―盆地相区杜内阶中的腕足动物群具有极高的属种分异度，不但有大量见于世界其他地方同期动物群中的分子，也包含有不少原本认为只在维宪阶或更高层位出现的类型或全新的类型，说明华南台缘斜坡―盆地相区不但与世界其他地区的腕足动物群之间存在密切的生物地理区系联系，而且华南台缘斜坡―盆地相区是杜内期腕足动物起源和辐射演化的重要策源地之一。许多属种可能是在这里起源，并迁移扩散到其他地方。  相似文献   

胞外聚合物对膜生物反应器运行性能的影响   总被引：3，自引：1，他引：3  

张凤君  王顺义  邓锡斌  赵芝清  沙娜  王鹤 《吉林大学学报(地球科学版)》2006,(Z1)

膜生物反应器处理污水过程中,依据胞外聚合物(EPS)、蛋白质、多糖、粘度等参数随时间的变化趋势以及对膜通量的影响,求出上述参数及蛋白质/多糖的比值与膜通量间的相关系数分别为0.28、0.57、0.38、0.14、0.70。结果表明:蛋白质/多糖的比值与膜通量的衰减速度两者相关系数最大。  相似文献   

酶法催化餐饮废油制备生物柴油的研究     

安永磊  唐唯森  高松 《吉林大学学报(地球科学版)》2006,(Z1)

以废物资源转化为宗旨,利用固定化脂肪酶催化餐饮废油与乙醇反应制备生物柴油,通过实验获得最佳酯化反应条件:反应温度47℃、有机溶剂为正己烷、醇油比3∶1,5次投加乙醇,酶用量为0.3g,反应时间32h时,生物柴油产率可达81%。  相似文献   

广东瑶岭钨矿矿化类型多样性及成矿规律研究     

王燕  陈梦熊  李明高  曾永熊 《矿产与地质》2006,(5)

近年来,广东瑶岭钨矿床在原来中型石英脉型黑钨矿床的基础上,又相继发现了花岗岩岩体带附近的矽卡岩型白钨矿化和深部花岗岩体中的构造蚀变岩型白钨矿化.通过对这新老发现的三种类型钨矿化地质特征及成矿规律的总结和归纳,建立了瑶岭不同类型钨矿化成生关系及成矿模式.研究认为,该模式可能会给整个粤北甚至南岭成矿带的地质找矿带来新的启示.  相似文献   

谁为王者     

本刊编辑部 《地图》2005,(2):F005-F005

不久前在国内公映的法国电影《虎兄虎弟》,引来掌声一片:一对健壮美丽的虎夫妻和刚出生不久的两个儿子在森林中享受着天伦之乐,然而人类摧毁了它们的家园,一家四口夫亡妻离,虎兄虎弟则背井离乡,沦为大众娱乐的玩偶。这是曾经拍摄过《熊的故事》的法国导演让·雅克·阿诺在2004年的最新作品,其关于动物、自然、友谊的真挚表达,令人唏嘘不已。按照达尔文的进化论,老虎在这个星球上呆的时间比我们要长得多,人在当猴子的时期,还是归这位响当当的“百兽之王”统治管辖呢,然而风水轮流转,不知何时老虎早已被人赶得无家可归、濒临灭绝,正是“山中无…  相似文献