鼻咽癌与土壤环境中化学元素的相关性研究

利用土壤元素数据２０６９４４８个，鼻咽癌死亡调查资料２２５６０例，研究了鼻咽癌死亡率与土壤环境中６１个元素质量分数的相关性。结果表明，汞、铅、硒、针、锡、钛、钽、溴、碘元素质量分数与鼻咽癌死亡率呈非常显著的正相关；铪元素质量分数与鼻咽癌死亡率呈显著的正相关；铟、镱、镥、铀、锆、铋、碲元素质量分数与鼻咽癌死亡率呈较显著的正相关。锰、钠、镁、钙、锶元素质量分数与鼻咽癌死亡率呈非常显著的负相关；钾、钡元素质量分数与鼻咽癌死亡率呈较显著的负相关。钒、铷、铯、银、铝、镓、铊、钪、钇、镧、铈、钕、钆、镝、钬、铒、铥、钼、钨、铁、砷、镉、钴、铬、铜、氟、镍、锌、锂、铍、硼、镨、钐、铕、铽、锗、锑元素质量分数与鼻咽癌死亡率无明显的相关性。     

Chemical composition of plant silica phytoliths

Silica phytoliths are a subgroup of biogenic opal. Silica phytoliths are formed in many plant species and remain preserved in soil and sediments after plant decay. The chemical composition of fossil phytoliths may reveal ancient plant taxa, soil composition and climate. However, actually detailed knowledge on silica phytolith composition is scarce. Here we present result of instrumental neutron activation analysis of barley awns, stems and leaves, and barley phytoliths. The elements of interest were Na, Mg, Al, Si, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Zn, As, Br, Rb, Sb, Cs, Ba, La, Ce, Sm, Eu, Tb, Dy, Yb, Hf, Ta, W, Th, and U. We compared three phytolith extraction methods: dry ashing, acid digestion, and acid digestion followed by incineration. We found that sole acid digestion is inefficient to remove organic matter. By contrast both dry ashing and acid digestion followed by incineration are suitable for phytolith analysis. Comparison of phytoliths with their source plant material shows that phytoliths are enriched in terrigenous elements such as Al, Sc, Ti, V, Cs, Fe, rare earth elements, and depleted in the major inorganic constituents of plants such as K, Ca, Mg, Mn, Cl and Br.     

我国城市土壤重金属的污染格局分析

收集了国内43个大中城市的3688个城区土壤重金属数据,通过描述性分析、评价分析、聚类分析等,初步确定了我国城市土壤重金属的污染格局.结果表明,我国城市土壤As、Cd、Cr、Cu、Hg、Ni、Pb、Zn的平均赋存量分别为13.39、0.68、63.04、38.17、0.31、26.18、47.34、137.72 mg·kg-1.Nemerrow指数、地质累积指数和潜在生态危害指数评价表明,污染最严重的城市是太原、南京、开封,主要污染重金属是Hg、Cd、Pb.43个城市中,上海、武汉、淄博、昆明、抚顺、昌吉、郑州、贵阳、成都、攀枝花、天津、珠海、大庆、北京、南宁、广州、香港、长春、太原等19个城市属于Cd强度污染;徐州、长沙、开封、重庆、乌鲁木齐、沈阳、西安、杭州、南京、兰州、洛阳等11个城市属于Hg-Cd强度污染、Pb中度污染;其余13个城市属一般轻度污染.长江以南城市土壤重金属污染比长江以北城市严重,中小城市土壤重金属污染低于特大城市.     

Assessment of a Smelter Impact Area Using Surface Soils and Plants

The concentrations of 37 trace elements (Ag, Ba, Be, Cd, Ce, Co, Cr, Cs, Cu, Dy, Er, Ga, Gd, Ge, La, Li, Mo, Nb, Nd, Ni, Pb, Pr, Rb, Sb, Sm, Sn, Sr, Tb, Th, Tl, U, V, W, Y, Yb, Zn and Zr) were determined by ICP-MS in surface soils and plants (Sida rhombifolia) sampled around a lead smelter in Lastenia, Province of Tucuman, NW Argentina. Soil and plant patterns of Pb, Cd, Ag, Zn and Cu demonstrate the effects of pollutant dispersion plumes following the prevalent wind directions. The high element concentrations observed, especially Pb (>5,000 mg/kg), could cause serious environmental problems in areas of close proximity to the smelter. Consequently, measures to assess potential consequences for the local population should be considered to determine if measures to protect the environment are necessary.     

贵州省原煤中微量元素的组成特征

研究了贵州省各主要煤田中主要采煤层的Ａｓ,Ｂ,Ｂａ,Ｂｅ,Ｃｄ,Ｃｏ,Ｃｒ,Ｃ,Ｈｇ,Ｌｉ,Ｎｉ,Ｐｂ,Ｓｂ,Ｓｅ,Ｓｒ,Ｔｌ,Ｖ,Ｚｎ等微量元素的组成特征,贵州省原煤中微量元素的含量总体上的世界范围内的一致,但Ｓｂ,Ａｓ,Ｈｇ等有害元素则明显富集,由于煤炭成因上的特殊性,其微量元素的组成除受煤植物的影响外,后期在煤作用对其有决定性的影响。     

Uncommon heavy metals,metalloids and their plant toxicity: a review

Heavy metals still represent a group of dangerous pollutants, to which close attention is paid. Many heavy metals are essential as important constituents of pigments and enzymes, mainly zinc, nickel and copper. However, all metals, especially cadmium, lead, mercury and copper, are toxic at high concentration because of disrupting enzyme functions, replacing essential metals in pigments or producing reactive oxygen species. The toxicity of less common heavy metals and metalloids, such as thallium, arsenic, chromium, antimony, selenium and bismuth, has been investigated. Here, we review the phytotoxicity of thallium, chromium, antimony, selenium, bismuth, and other rare heavy metals and metalloids such as tellurium, germanium, gallium, scandium, gold, platinum group metals (palladium, platinum and rhodium), technetium, tungsten, uranium, thorium, and rare earth elements yttrium and lanthanum, and the 14 lanthanides cerium, dysprosium, erbium, europium, gadolinium, holmium, lutetium, neodymium, promethium, praseodymium, samarium, terbium, thulium and ytterbium.     

Transformations of pentachlorophenol

ANALYTICAL METHODS IN HUMAN TOXICOLOGY, Part 1, edited by A. S. Curry, Reading, U.K., 319 pages (including 91 figures, 28 tables, references added to each chapter, and a subject index of 19 pages), hard cover, format 242 × 160 mm, ISBN 3–527–26284–9, Verlag Chemie GmbH, Weinheim, Deerfield Beach (Florida), and Basle (1985), DM 148.00, US$65.00.

TOXICOLOGY AND BIOLOGICAL MONITORING OF METALS IN HUMANS (INCLUDING FEASIBILITY AND NEED), by Bonnie L. Carson (Midwest Research Institute, Kansas City, Missouri), Harry V. Ellis III (PRC Engineering, Chicago, Illinois), and Joy L. McCann (Midwest Research Institute, Kansas City, Missouri), 328 pages (including one table on human low‐level exposure to metals: exposure levels, biological effects, concentrations in biological media; including also references for each of 69 metals and a valuable index of 24 pages), hard cover, format 236 × 161 mm, ISBN 0–87371–072‐X, Lewis Publishers, Inc., Chelsea, Michigan 48118 (1986), £45.95.

PHOTOMETRIC METHODS IN INORGANIC TRACE ANALYSIS (Comprehensive Analytical Chemistry Volume XX), by Endre Upor, M. Mohai and Gy Novak, Mecsek Ore‐Mining Enterprise, Pecs, Hungary (translated and revised), 404 pages (including 9 figures, 44 tables, a list of 50 pages (appendix) of the most important reagents, and an index of 6 pages), cloth, format 229 × 157 mm, ISBN 0–444–99588–9, Elsevier Science Publishers B.V., Amsterdam and Akadémiai Kiadò, Budapest (1985), hfl 300.00, US$111.00.

CONCEPTS IN MARINE POLLUTION MEASUREMENTS, edited by Harris H. White, National Oceanic and Atmospheric Administration, Rockville, Maryland 20852, 743 pages (including 153 figures, 51 tables, references added to each paper, and an index of 7 pages), cloth, format 236 × 162mm, ISBN 0–943676–18–5, Maryland Sea Grant Publication, College Park, Maryland 20742 (1984), US$12.50.

DETERMINATION OF ORGANIC SUBSTANCES IN WATER, Volume 1, by Thomas Roy Crompton, 560 pages (including 260 figures, 167 tables, references added to the four chapters, and an index of 12 pages), hard cover, format 236 × 161 mm, ISBN 0–471–90468–6, John Wiley &; Sons, Chichester, New York, Toronto, and Singapore (1985), £49.95.

MARINE AND ESTUARINE GEOCHEMISTRY, by Anne C. Sigleo, U.S. Geological Survey, Reston, Virginia, and Akihiko Hattori, Ocean Research Institute, University of Tokyo, 331 pages (including 121 tables, 60 figures, references added to each chapter, and an index of 3 pages), hard cover, format 235 × 160 mm, ISBN 0–87371–007‐X, Lewis Publishers, Inc., Chelsea, Michigan 48118 (1985), £35.90.

INDOOR AIR AND HUMAN HEALTH, by Richard B. Gammage and Stephen V. Kaye, Oak Ridge National Laboratory, Tennessee 37831, 430 pages (including 54 figures, 91 tables, references added to each chapter, a summary and conclusions of 5 pages, and an index of 6 pages), hard cover, format 242 × 164 mm, ISBN 0–87371–006–1, Lewis Publishers, Inc., Chelsea, Michigan 48118 (1985), £35.90.

INDUSTRIAL EXPOSURES IN ALUMINIUM PRODUCTION, COAL GASIFICATION, COKE PRODUCTION, AND IRON AND STEEL FOUNDING, POLYNUCLEAR AROMATIC COMPOUNDS PART 3, IARC Monograph No. 34 on the Evaluation of the Carcinogenic Risk of Chemicals to Humans, by G. Matanoski et al., Johns Hopkins University, Baltimore, Maryland 21205, 219 pages (including 7 figures, 49 tables, two appendices on chemicals considered in the volume, and already evaulated earlier, a glossary of two pages, and a cumulative index to IARC Monographs 1 to 34 of 21 pages), soft bound, format 240 × 179 mm, ISBN 92–832–1234–7, International Agency for Research on Cancer, Lyon and Geneva (1984), SFr. 48.00, US$20.00.

BITUMENS, COAL‐TARS AND DERIVED PRODUCTS, SHALE‐OILS AND SOOTS, POLYNUCLEAR AROMATIC COMPOUNDS PART 4, IARC Monograph No. 35 on the Evaluation of the Carcinogenic Risk of Chemicals to Humans, by E. Bingham et al., University of Cincinnati, Ohio 45267, 271 pages (including 10 figures, 61 tables, glossaries, and a cumulative index to IARC Monographs 1 to 35 of 21 pages), soft bound, format 240 × 179mm, ISBN 92–832–1235–5, International Agency for Research on Cancer, Lyon and Geneva (1985), SFr. 70.00, US$25.00.

THE ROLE OF CHEMICALS AND RADIATION IN THE ETIOLOGY OF CANCER, Volume 10 of Carcinogenesis—A Comprehensive Survey, by Eliezer Huberman and Susan H. Barr, Argonne National Laboratory, Illinois 60439, 538 pages (including 173 figures, 72 tables, references added to each chapter, an index of 10 pages), linen, format 241 × 167 mm, Raven Press, New York City 10036 (1985), US$76.00.

CHEMICAL CARCINOGENS, SECOND EDITION, ACS Monograph 182, by Charles E. Searle, University of Birmingham, England, 1412 pages (including 61 figures and schemes, 178 tables, many formulae, references added to each contribution, an author index of one page, and an excellent subject index of 38 pages), linen, format 235 × 163 mm, ISBN 0–8412–0869–7, American Chemical Society, Washington, DC 20036 (1984), US$155.95 (in U.S.A. and Canada US$129.95).

ALIPHATIC AND POLYHALOGENATED CARCINOGENS, CHEMICAL INDUCTION OF CANCER VOLUME IIIB (STRUCTURAL BASES AND BIOLOGICAL MECHANISMS), by Joseph C. Arcos et al., U.S. Environmental Protection Agency and Tulane University Medical Center, New Orleans, Louisiana, 598 pages (including 23 figures, 77 tables, references added to each section, updating notes, 4 updating appendices, and an index of 28 pages), linen, format 234 × 164 mm, ISBN 0–12–059323, Academic Press, Inc., Orlando, Florida 32887, and London NW1 7DX, U.K. (1985), US$98.50.

ADVANCES IN HEALTH RISK ASSESSMENT FOR SYSTEMIC TOXICANTS AND CHEMICAL MIXTURES, Toxicology and Industrial Health Series Volume 1 (number 4), by Jerry F. Stara and Linda S. Erdreich, U.S. Environmental Protection Agency, Cincinnati, Ohio 45268, 364 pages (including 34 figures, 76 tables, references and discussion remarks after the contributions, a list of participants of 3 pages, and an index of 14 pages), cloth, format 261 × 186 mm, ISBN 0–911131–90–6, Princeton Scientific Publishing Co., Inc., Princeton, New Jersey 08540 (1985), £53.35.

REPRODUCTIVE HAZARDS OF INDUSTRIAL CHEMICALS (an evaluation of animal and human data), by Susan M. Barlow and Frank M. Sullivan, Guy's Hospital Medical School, University of London, U.K., 610 pages (including 3 tables, references (up to 1979, and an index of 11 pages), hard cover, format 235 × 159 mm, ISBN 0–12–078960–4, Academic Press Inc., London, New York and Orlando (1984), USS75.00.

MAXIMUM CONCENTRATIONS AT THE WORKPLACE AND BIOLOGICAL TOLERANCE VALUES FOR WORKING MATERIALS, Reports No. XX and XXI of the Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area, of the Deutsche Forschungsgemeinschaft (Prof. Dr Dietrich Henschler, University of D‐8700 Würzburg), 92 resp. 94 pages, paper board, format 240 × 170 mm, ISBN 3–527–27332–8 resp. 3–527–27340–9, VCH Verlagsgesellschaft D‐6940 Weinheim (1984 resp. 1985).     

常用杀菌剂对啶虫脒中华蜜蜂毒性潜在增效作用研究

啶虫脒对蜜蜂急性毒性较低,且允许在作物花期施用,而杀菌剂也是蜜源植物花期常用药剂。本文采用点滴法和摄入法测定了10种常用杀菌剂对啶虫脒中华蜜蜂毒性的潜在增效作用。结果表明,点滴田间实际暴露剂量的杀菌剂使啶虫脒对中华蜜蜂的毒性不同程度的增加。点滴杀菌剂和啶虫脒24 h、48 h后,咪鲜胺、丙环唑、腈菌唑、戊唑醇、苯醚甲环唑、嘧菌酯、己唑醇、吡唑醚菌酯、三唑酮、氟硅唑使啶虫脒毒性分别增加14.02、10.74、8.50、7.92、4.77、4.28、4.19、4.07、2.74、2.67倍和8.01、10.14、4.80、7.09、2.66、2.56、3.62、2.69、2.24、1.49倍。摄入田间实际暴露剂量的杀菌剂和啶虫脒混剂24 h、48 h后,啶虫脒对中华蜜蜂的毒性增加。其中,丙环唑、氟硅唑、苯醚甲环唑、嘧菌酯、咪鲜胺使啶虫脒的毒性分别增加3.62、2.46、2.10、1.98、1.56倍和2.07、2.81、2.20、2.58、2.23倍。因此蜜源植物花期应避免丙环唑、咪鲜胺、戊唑醇、腈菌唑与啶虫脒先后喷施或混合喷施,慎用己唑醇等其他6种杀菌剂,以防啶虫脒残留导致中华蜜蜂采集蜂中毒。     

Elemental composition of Jamaican foods 1: A survey of five food crop categories

The concentrations of 27 elements in Jamaican food categories consisting of fruit, legumes, leafy and root vegetables and other root crops are reported. The main analytical techniques used were neutron activation analysis and flame and graphite furnace atomic absorption spectrophotometry. The results are compared, where possible, with values from Denmark, the United Kingdom, the United States and Nigeria, and with some regulatory limits. Over 75% of the results for antimony, arsenic, barium, cerium, thorium and uranium were below the respective sample detection limits but even among these, some of the maximum values observed indicate that further examination may be useful for those foods grown in the regions of highest uptake and consumed in large amounts. The other elements reported are bromine, cadmium, calcium, caesium, cerium, chromium, copper, europium, hafnium, iron, lanthanum, lead, magnesium, manganese, phosphorus, potassium, rubidium, scandium, samarium, sodium, strontium, thorium, uranium, and zinc. Many of these elements occur at concentration levels above those reported from the other countries but it seems unlikely that most of these will contribute significantly to public health risk. However, at this stage cadmium clearly appears to be the element of greatest concern in the Jamaican food chain. The observed range of cadmium concentrations suggests that factors such as land selection, coupled perhaps where necessary, with suitably modified agricultural practices, is a feasible way to reduce the cadmium content of certain local foods.     

Occurrence,toxicity and adsorptive removal of the chloramphenicol antibiotic in water: a review

Chloramphenicol is a broad-spectrum bacterial antibiotic used against conjunctivitis, meningitis, plague, cholera, and typhoid fever. As a consequence, chloramphenicol ends up polluting the aquatic environment, wastewater treatment plants, and hospital wastewaters, thus disrupting ecosystems and inducing microbial resistance. Here, we review the occurrence, toxicity, and removal of chloramphenicol with emphasis on adsorption techniques. We present the adsorption performance of adsorbents such as biochar, activated carbon, porous carbon, metal–organic framework, composites, zeolites, minerals, molecularly imprinted polymers, and multi-walled carbon nanotubes. The effect of dose, pH, temperature, initial concentration, and contact time is discussed. Adsorption is controlled by π–π interactions, donor–acceptor interactions, hydrogen bonding, and electrostatic interactions. We also discuss isotherms, kinetics, thermodynamic data, selection of eluents, desorption efficiency, and regeneration of adsorbents. Porous carbon-based adsorbents exhibit excellent adsorption capacities of 500–1240 mg g^?1. Most adsorbents can be reused over at least four cycles.

     

Calibration for the determination of 19 trace elements in serum and urine

A fast, high-throughput and accurate method was developed for determination of Al, As, Ba, Cd, Co, Cr, Cs, Cu, Fe, Mn, Ni, Pb, Se, U, Zn, Sb, Sn, I and Hg in urine and serum by inductively coupled plasma mass spectrometry. The samples were directly analyzed after 1/20 (v/v) dilution in 0.4% (v/v) HNO₃ and 0.005% Triton X-100. Three calibration modes were tested: aqueous and matrix matching with urine and serum. The accuracy was tested using reference materials of serum, urine and spiking. Results showed that the use of matrix matching calibration reduced the interferences and improved the recoveries for Al, Co, Pb and I in urine. The matrix matching did not affect the results considerably for serum. When serum was spiked with As, Co, Cs, Pb, U, Hg, I, Ba, Al, Cr and Ni, only matrix matching presented good recoveries. Helium was used as a collision cell gas reducing effectively polyatomic interferences for Al, Mn, Cu, Ni, Cr, Zn, As and Fe. Selection of the best internal standard was carried out for each element. The use of diluted HNO₃ improved the limit of detection. Finally, the method was applied successfully in samples of urine from workers occupationally exposed.     

Trace element atmospheric pollution in South Albania studied by the moss technique and inductively coupled plasma–atomic emission spectrometry

Monitoring hazardous air pollutants is needed for understanding their spatial and temporal distribution and ultimately to minimize their harmful effects. For the first time, the moss biomonitoring technique has been applied to air pollution monitoring in South Albania. Moss samples were collected during the period of September–October 2010, and were analyzed for total concentration of the elements Al, As, Ba, Ca, Cd, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, P, Pb, Sr, V, and Zn by inductively coupled plasma–atomic emission spectrometry. Geographical distribution maps of the elements over the sampled territory were constructed using geographic information systems technology. Multivariate statistical analysis was applied to distinguish elements mainly of anthropogenic origin from those predominantly originating from natural sources. Four factors were identified: Factor 1 reflects wind-blown mineral particles or local emissions from industry (Al, As, Ba, Ca, Cr, Cu, Fe, Mn, Ni, V, Zn); Factor 2 is related to long-range atmospheric transport of elements or local emissions from industry (Cd, Pb); Factor 3 (Na, Mg) and Factor 4 (K) reflect the natural origin of elements as crustal, marine, and vegetation components.     

Development and applications of functional gene microarrays in the analysis of the functional diversity, composition, and structure of microbial communities

Functional gene arrays (FGAs) are a special type of microarrays containing probes for key genes involved in microbial functional processes, such as biogeochemical cycling of carbon, nitrogen, sulfur, phosphorus, and metals, biodegradation of environmental contaminants, energy processing, and stress responses. GeoChips are considered as the most comprehensive FGAs. Experimentally established probe design criteria and a computational pipeline integrating sequence retrieval, probe design and verification, array construction, data analysis, and automatic update are used to develop the GeoChip technology. GeoChip has been systematically evaluated and demonstrated to be a powerful tool for rapid, specific, sensitive, and quantitative analysis of microbial communities in a high-throughput manner. Several generations of GeoChip have been developed and applied to investigate the functional diversity, composition, structure, function, and dynamics of a variety of microbial communities from different habitats, such as water, soil, marine, bioreactor, human microbiome, and extreme ecosystems. GeoChip is able to address fundamental questions related to global change, bioenergy, bioremediation, agricultural operation, land use, human health, environmental restoration, and ecological theories and to link the microbial community structure to environmental factors and ecosystem functioning.     

Diversity of microflora in the gut and casts of tropical composting earthworms reared on different substrates

The diversity of fungi, bacteria, yeast, actinomycetes and protozoa were analysed in the gut and casts of Eudrilus eugeniae, Lampito mauritii, Eisenia fetida and Perionyx excavatus, both qualitatively and quantitatively as influenced by different feed substrates like clay loam soil, cowdung and pressmud. While actinomycetes (Streptomyces albus, S. somaliensis, Nocardia asteroides, N. caviae and Saccharomonosporia) were not digested by any of these species of worms, protozoa (Amoeba proteus, A. terricola, Paramecium trichium, Euglena viridis, E. orientalis, Vorticella picta and Trichomonas hominis) and yeast (Candida tropicalis, C. krusei C. albicans and Cryptococcus neoformans) were totally digested. Certain species of fungi (Saksenae vasiformis, Mucor plumbeus, Cladosporium carrionii, C. herbacium, Alternaria sp., Cunninghamella echinulata, Mycetia sterila, Syncephalostrum racemosum, Curvalaria lunata, C. geniculata and Geotrichum candidum) and bacteria (Pseudomonas aeruginosa, Bacterium antitratum, Mima polymorpha, Enterobacter aerogenes, E. cloacae, Proteus vulgaris, P. mirabilis, P. rettgeri, Escherichia coli, Staphylococus citreus, Bacillus subtilis, B. cereus, Enterococci and Micrococci) were completely digested. Certain other species were not digested fungi like Aspergillus fumigatus, A. flavus, A. ochraceous, Trichoderma koningii (except by Eeugeniae), Fusarium moniliforme (except by E. eugeniae) and Rhizopus sp., and bacteria like Klebsiella pneumoniae and Morganella morganii) and these were multiplied during the transit of the organic residues through the gut of worms. The microbial proliferation was more in the casts, due to the environment prevailing--rich in nutrient supply and large surface area available for growth and reproduction of the microbes that lead to enhanced microbial activity and humic acid contents in the casts.     

A suggested local regions in the Southern Gulf of Mexico using a diatom database (1979-2002) and oceanic hidrographic features

A diatom data-base of 255 species obtained from 14 oceanographic cruises (14801 entries of 647 sampling sites) together with the analysis of oceanic features were used to establish four local regions in the southern Gulf of Mexico. In addition, common species for each region were designated. This study is based on the application of cluster analysis and the species frequency data. Material for this undertaking consisted of water and net samples obtained between June 1979 and December 2002. Results show that the most frequent species (> 40%) were: Asterionellopsis glacialis, Bacteriastrum delicatulum, B. hyalinum, Chaetoceros affinis, C. coarctatus, C. compresus, C. curvisetus, C. danicus, C. decipiens, C. diversus, C. lorenzianus, C. pelagicus, C. peruvianus, Coscinodiscus radiatus, Cylindrotheca closterium, Guinardia flaccida, Hemiaulus hauckii, H. membranaceus, H. sinensis, Leptocylindrus danicus, Neocalyptrella robusta, Nitzschia bicapitata, Pleurosigma diverse-striatum, Proboscia alata, Pseudo-nitzschia pungens, Pseudosolenia calcar-avis, Rhizosolenia imbricata, R. setigera, Skeletonema costatum, Thalassionema bacillare, T frauenfeldii, T nitzschioides and Thalassiosira eccentrica. The species composition for each region and season are discussed. Itis concluded that sampling site assemblages are related to oceanographic conditions. A total list of species composition is given, forty-seven species taxa being new records for this area.     

A Diverse and Endangered Aquatic Ecosystem of the Southeast United States

We document the biodiversity and conservation status of an extraordinarily diverse and endangered ecosystem in the United States that has failed to attract the same attention as tropical ecosystems—the rivers and streams of Alabama and adjoining states. Relative to North America as a whole, Alabama is a highlight of aquatic diversity supporting 38% of native fresh water fishes, 43% of native freshwater gill-breathing snails, 60% of native mussels, and 52% of native freshwater turtles. Of these, 41%, 77%, 34%, and 22% of the fishes, snails, mussels, and turtles, respectively, are endemic to Alabama and an adjacent state. Like many tropical systems of developing nations, this fauna is in an imperiled state, with 10%, 65%, 69%, and 43% of Alabama's fishes, gill-breathing snails, mussels, and turtles, respectively, considered either extinct, endangered, threatened, or of special concern. Unlike tropical systems, however, little effort has been made to protect the taxa and their habitats. Only 40% of fishes, 1% of gill-breathing snails, 32% of mussels, and 20% of freshwater turtles are formally listed as either threatened or endangered via the U.S. Endangered Species Act of 1973; no critical habitat has been protected. Clearly, the biodiversity crisis in not limited to tropical systems of developing nations. Although the Endangered Species Act of 1973 helps to ensure a future of sustainable diversity, efforts must be made to hasten recognition, protection, and recovery of critical habitat, particularly for hotspots such as the aquatic systems of Alabama.     

The chemistry and parent material of urban soils in Bristol (UK): implications for contaminated land assessment

An earlier survey of topsoil from parks and allotment in the city of Bristol (UK) revealed the presence of relatively high levels of “pseudo-total” Cd, As, Cu, Pb and Zn, with Cd and As exceeding present UK soil guidelines. This follow-up work aimed at (1) estimating geochemical thresholds for these elements based on “near-total” soil, bedrock and sediment heavy metals and (2) determining the genetic relationship between soil and bedrock using rare earth elements (REEs or lanthanides) as tracers. “Near-total” concentration of 34 elements (Al, Ca, Fe, K, Mg, Na, As, Ba, Cd, Cr, Cu, Li, Mn, Ni, P, Pb, Sc, Ti, V, Zn, Y and the rare earth elements Ce, Dy, Er, Eu, Gd, Ho, La, Lu, Nd, Pr, Sm, Tb, Yb) were obtained by ICP-MS and ICP-OES. The results show that the soil composition is largely controlled by the soil parent material, though extreme outliers are indicative of contamination at a few sites of parkland and allotments. Cumulative frequency plots show the presence of different data sets for which separate “background” values should be determined. The REE data provide evidence that weathering of the underlying sandstone was a determinant factor leading to the relatively high heavy metal enrichment found in soil samples and sediments. Reference to UK soil guidelines to decide on possible remediation measures could be very misleading due to the natural high background levels of some elements in the underlying bedrock. Before defining land as “contaminated”, a thorough geochemical investigation is required at local scale in order to produce a more realistic and correct environmental assessment.     

Some characteristics of the distribution of heavy metals in urban topsoil of Xuzhou,China

An assessment is presented of distribution characteristics of heavy metals in the urban topsoil from the city of Xuzhou. The concentrations of Ag, Al, As, Au, Ba, Be, Bi, Cd, Co, Cr, Cu, Fe, Ga, Hg, Li, Mn, Mo, Ni, Pb, Pd, Pt, Sb, Sc, Se, Sn, V and Zn have been determined from 21 soil samples. Examination of lognormal distribution plots indicates that the diagrams of Al, Be, Fe, Ga, Li, and V are almost linear suggesting that these metals are almost unaffected by anthropogenic activities while the plots for As, Cd, Cu, Pb, Pd, Pt, Se, Zn and others are not linear probably due to anthropogenic activities from which these metals are delivered to the soils. Al is used for mineralogical normalization of these data. An evaluation of background values for topsoil is also carried out by means of lognormal distribution plots. The results show our background values obtained from the lognormal distribution plots are comparable to those values of uncontaminated soils of Xuzhou obtained by previous work except for Cd and Hg. At present, no explanation for the exceptions Cd and Hg can be given.     

燕山典型流域两种造林树种生态系统碳储量及固碳潜力研究

选择燕山典型流域6个林龄序列的小叶杨（Populus simonii）和5个林龄序列的山杏（Prunus sibirica）主要造林树种为研究对象,利用时间替代空间样地测量法量化退牧还林后生物量碳储量、凋落物碳储量和土壤碳储量及生态系统碳储量的变化规律,同时以各组成碳库-林龄序列中的最大碳储量之和作为生态系统饱和碳储量,以未退牧的天然草地生态系统碳储量作为初始植被类型的碳储量,分析总结了退牧还林对生态系统碳储量和碳循环的影响。结果表明,退牧还林后生态系统的生物量碳储量、凋落物碳储量基本随退牧年限的增加而增加,土壤碳储量随退牧年限的增加呈现先减小后增加的趋势。在没有人为干扰的情况下,9、15、18、22及29 a生小叶杨林的生态系统碳储量分别为7147.45、7461.67、7509.895、8468.375及8247.85 g·m^-2,9、15、18、22及26 a生山杏林的生态系统碳储量分别为6695.44、6700.82、8011.86、8001.92及7981.92 g·m^-2;9、15、18、22、29及36 a生小叶杨林的生态系统固碳潜力分别为757.08、1071.3、1119.53、2078.01、1857.48及1312.21 g·m^-2,9、15、18、22及26 a生山杏林的生态系统固碳潜力分别为310.45、1621.49、1611.55、1591.55及757.08 g·m^-2。长期来看,研究区退牧还林对提高生态系统碳汇能力是可观的、积极的。研究结果对提高造林对碳汇影响的估测能力提供数据支持,也为政府参与国际全球气候变化的谈判提供一个很好的案例研究和科学根据。     

三峡库区主要粮食作物和土壤中重金属的相关性及富积特征分析

采用野外采样和室内分析,试验结果表明三峡库区土壤中重金属Cu、Zn、Pb、Cd、Fe、Cr的变异系数小于50%,重金属的含量比较稳定。稻谷（Oryza sativa）中Cu、Zn、Pb、Cd、Fe、Mn、Cr,玉米（Zea mays）中Pb、Cd、Fe、Mn、Cr和小麦（Triticum aestivum）中Cu、Pb、Cd、Fe、Mn、Cr的变异系数大于50%。土壤、稻谷、玉米、小麦中大部分重金属呈偏态分布。土壤中重金属间均为正相关,且极显著正相关性明显。稻谷、玉米、小麦中重金属间有正相关,也有负相关,但正相关明显多于负相关;稻谷、玉米、小麦中Mn同其它重金属间均有显著正相关性,协同作用明显。稻谷、玉米、小麦中Pb、Cd、Cr的样本超标率较大,污染明显,并且稻谷中Cd与土壤中Cd有直线关系。