Antimony, Arsenic and Thallium Bioaccumulation in Asiatic Clam (Corbicula fluminea) Transplanted along the Manadas Creek, Laredo, Texas

Manadas Creek is an urban tributary of the Rio Grande that flows past a decommissioned antimony smelter and processing plant. This antimony plant is associated with heavy metal contamination in the creek and still poses a threat to the surrounding aquatic environment. Corbicula fluminea was used to determine bioaccumulation from the water column and sediments in Manadas Creek. The metals arsenic (As), antimony (Sb) and thallium (Tl) were analyzed in the water, sediments, gills, mantle, foot, digestive (DI) tract, gonads and shell of clams being monitored at eight sites between March and August 2013. Sediment, water, and dissected Corbicula fluminea samples from different sites in the Creek were acid-digested and analyzed by Inductively Coupled Plasma Optical Emission Spectroscopy. High levels of antimony (25.88 ug/L;75.96 mg/kg) and arsenic (8.26 ug/L;6.41 mg/kg) in the water and sediments were observed at the site downstream from the smelter. There were no detectable concentrations of arsenic, antimony, or thallium in the shell of C. fluminea. Arsenic and antimony were detected in the tissues of C. fluminea but thallium was not detected. Based on the results, the organotropism for arsenic is DI tract > gills > gonads > foot > mantle > shell and the organotropism for antimony is gills > DI tract > gonads > mantle > foot > shell. This study shows that the Asiatic clam (Corbicula fluminea) is a useful bio-monitor to provide data on the status of metal pollution in Manadas Creek, Laredo, Texas.

Diel,seasonal,and annual variations of fish assemblages in intertidal creeks of the Changjiang River estuary

The use patterns of salt marsh habitats by fish assemblages were investigated in two welldeveloped intertidal creeks in the Changjiang(Yangtze)River estuary on spatial and temporal scales.Samples were collected using fyke nets at two sites during day and night in each season throughout four years.Notable changes in fish assemblages were detected over seasonal and interannual cycles,with many more marine species present in winter assemblages,whereas freshwater and estuarine species characterized the other seasonal samplings.The appearance of catadromous species in intertidal creeks mainly depended upon their specific physiological requirements,such as spawning migration.No significant diel shifts were observed in fish assemblages.This diel pattern may be a combined consequence of avian predation pressure and other drivers(i.e.,inherent living behaviors,food availability,and predation by piscivorous fishes).The spatial difference in fish community was insignificant even though the two intertidal creeks were different in size.Intertidal creeks with different size could possess similar ecological value for fish fauna.Redundancy analysis(RDA)showed that biological factors exerted greater effects on fish assemblages than physical variables.Temporal variations were strongly facilitated by food availability,but negatively impacted by avian predation.Salinity,water temperature,and river runoff had weak influence on temporal variations of fish communities.The lengthfrequency distribution showed that the fish collected in these two sites mainly consisted of young-of-year and juvenile fish,which confirmed that the creeks provided important nursery and forage roles in the process of fish ontogenetic development.Further,we proposed that salt marsh conservation management should be equally applied to all well-developed intertidal creeks regardless of creek size.

地震综合解释技术在尼日尔三角洲盆地STUBB CREEK区块中的应用

通过对尼日尔三角洲盆地STUBB CREEK区块复杂断块油藏的研究,以新采集的三维地震资料为基础,探讨了复杂断块油藏的研究思路及研究方法,利用相干数据体、时间切片研究断层平面展布规律,借助三维可视化解释技术查看断层面空间展布形态,综合地震资料综合解释的成熟技术,探索出一套适合复杂断块油藏研究的思路,形成了一套有效的综合解释的技术流程。在研究的基础上部署了两口井,取得了油气突破。

储层横向预测技术在尼日利亚Stubb Creek油田的应用

Stubb Creek油田研究工区面积42 km2,研究层位是阿格巴达组的C3、C7、C9、D1、D3、D5、D8小层。根据已钻探的4口井和现有的认识成果,进行了测井曲线标准化、井震标定、体系域的层序划分,进行了岩石物理和岩相物理的研究,通过多种地震相结合单井相,刻画出了上述7层的有利相带。用支持向量机技术,进行了泥质含量的分频反演,通过砂岩的泥质含量门槛值计算了上述7层的砂体厚度,筛选了C9、D3两个有利相带。在有利相带控制下雕刻了过井砂体的顶面构造图和砂体厚度等值线图,并进行了综合评价。

Jackson Creek中学的“戏趣”教育模式探略

Jackson Creek中学是美国印第安纳州的一所五星级初中。该校的"戏趣"教育模式颇受瞩目,诸如形同"剧场"的流动课堂、人人"有戏"的团队合作、情境"入戏"的填字训练、现场"看戏"的调研实践、情状"戏谑"的教师言行,等等,其生发的"趣味"易激发学生的积极性、参与度,吸引学生的注意力,有利于教学活动的开展和学生个性的培养,从而能形成良性的课堂教学和教育模式。其"戏趣"教育模式值得我们借鉴,将能促进和优化已有的教育模式和教学形态。

用性价比说话--评英国Creek 4330 MK3功放

当我常常用性价比这个指标来评点一部器材的时候,不禁会想到,性价比究竟是生产者刻意为之的产品指标呢,还是迫于市场与销售份额的压力而不得已的追求?对于一个设计师来讲,是用不惜一切代价但取好声的方法来完成设计任务来得爽呢,还是要在成本与声音之间苦苦寻找平衡,绞尽脑汁地苦苦思索最佳设计方案而更为有趣呢?想来想去,我也没有得到答案.或许,对于生产、设计这两方面,性价比大概就意味着百分之一的灵感加上百分之九十九汗水混合而成的结晶.

航空磁法在澳大利亚北领地Tennant Creek金矿田勘探中的应用

Tennant Creek金矿田矿床类型属铁氧化物型铜金矿(IOCG),含矿部位均呈现高的航磁异常。本区矿体地表露头以褐铁矿为主,深部以磁铁矿为主,高品位的金通常位于铁矿体底部,呈细脉-浸染状产出。为了进一步寻找IOCG型矿床,在Tennant Creek金矿田内28 904区块开展了大比例尺航空磁法工作,综合分析航磁-地层特征,圈出航磁异常17处。其中2处异常经地表查证,发现了大型褐铁矿化带,并有Au异常显示。下一步若对其它异常进行钻探验证,证明其深部存在IOGC型金矿,则说明大比例尺航空磁法测量在Tennant Creek金矿田是有效的找矿方法。

Stubb Creek边际油田水平井部署参数优化研究

针对Stubb Creek边际油田油藏过渡带宽,纯油带较窄,边水强,适合采用水平井开发的特点,借鉴国内比较成功的理论和实践,应用专业软件模拟,对水平井井段长度、部署参数等进行优化研究,提出了该油田水平的部署方案,以扩大单井控制储量,提高采油速度和采收率。

美国俄亥俄州Sugar Creek流域的病原微生物来源分析

为了解美国俄亥俄州Sugar Creek流域的病原微生物污染程度和污染源,为决策层制定行之有效的治污办法提供数据支持,利用拟杆菌分子溯源技术跟踪测定了上游水域21个取样点微生物污染状况,并调查了水域内土地利用及化粪池系统情况。结果表明:Sugar Creek流域受到微生物严重污染,除社区居民饮用水源外,其余20个取样点均超过州环保部娱乐用水安全标准(235个/100mL),20个样点(95.2%)均受到人粪便污染,其中有4个样点受动物粪便污染。不适合的污水处理系统、化粪池污水直排和化粪池泄漏是污染的主要原因。

Assessment of Sea Water Inundation Along Daboo Creek Area in Indus Delta Region, Pakistan

Indus Deltaic Region(IDR) in Pakistan is an erosion vulnerable coast due to the high deep water wave energy. Livelihood of millions of people depends on the fisheries and mangrove forests in IDR. IDR consists of many creeks where Daboo is a major creek located at southeast of the largest city of Pakistan, Karachi. Unfortunately, there has been no detailed study to analyze the damages of sea water intrusion at a large temporal and spatial scale. Therefore, this study is designed to estimate the effects of sea water inundation based on changing sea water surface salinity and sea surface temperature(SST). Sea surface salinity and SST data from two different surveys in Daboo creek during 1986 and 2010 are analyzed to estimate the damages and extent of sea water intrusion. Mean salinity has increased 33.33% whereas mean SST decreased 13.79% from 1987 to 2010. Spatio-temporal analysis of creek area using LANDSAT 5 Thematic mapper(TM) data for the years 1987 and 2010 shows significant amount of erosion at macro scale. Creek area has increased approximately 9.93%(260.86 m^2 per year) which is roughly equal to 60 extensive sized shrimp farms. Further Land Use Land Cover(LULC) analyses for years 2001 and 2014 using LANDSAT 7 Enhanced Thematic Mapper Plus(ETM+) has indicated 42.3% decrease in cultivated land. Wet mud flats have spread out at the inner mouth of creek with enormous increase of 123.3%. Significant sea water intrusion has increased the area of barren land by 37.9%. This also resulted in overall decrease of 6.7% in area covered by mangroves. Therefore, this study recorded a significant evidence of sea water intrusion in IDR that has caused serious damages to community living in the area, economical losses. Additionally, it has also changed the environment by reducing creek biological productivity as reported by earlier studies over other regions of the world.

澳大利亚北领地Pine Creek造山带中部地区金矿成矿规律

Pine Creek造山带中部地区是北领地三大金矿矿集区之一,区内金矿床/矿点主要有三种类型:a)石英脉型金矿,b)条带状铁质岩相关金矿,c)金-多金属型金矿。本文通过梳理金矿床/矿点数据库,分析各类型金矿床/矿点的分布情况以及典型矿床的地质特征,总结了各类型金矿的空间分布与地层、构造、岩浆岩的关系,矿化局部富集规律等。

EVOLUTION OF RAPIDS OF CREEK MOUTH－BAR AT GEZHOUBA RESERVOIR AND THE IMPACTS ON NAVIGABLE CHANNEL IN THE UPPER REACHES OF THE CHANGJIANG RIVER

ＥＶＯＬＵＴＩＯＮＯＦＲＡＰＩＤＳＯＦＣＲＥＥＫＭＯＵＴＨ－ＢＡＲＡＴＧＥＺＨＯＵＢＡＲＥＳＥＲＶＯＩＲＡＮＤＴＨＥＩＭＰＡＣＴＳＯＮＮＡＶＩＧＡＢＬＥＣＨＡＮＮＥＬＩＮＴＨＥＵＰＰＥＲＲＥＡＣＨＥＳＯＦＴＨＥＣＨＡＮＧＪＩＡＮＧＲＩＶＥＲ￥ＬｉｎＣ...

Review Paper of “The Buffalo Creek Disaster”

"The buffalo creek disaster"mainly tells about a true story of"how a small West Virginia community responded to a horrendous coal-mining disaster that killed over 125 people and left thousands homeless".(Gerald M. Stern, 2008) I use two aspects- the analysis of legal content, the human factors- to analyse the issue that how people could deal with the man-made disaster.

Assessment of Mangrove Covers Change and Biomass in Mida creek, Kenya

This study uses old aerial photographs, current high resolution satellite images and ground truthing to analyze the patterns and dynamics of Mida Creek mangrove forest changes over 41 years from 1969-2010. A non-distractive method was used to collect data on 25 sample plots and 934 trees were measured to estimate the above ground biomass and carbon stock of the forest. General published allometric equations with variables of Diameter at Breast Height (DBH) and wood density (ρ) which were species specific were used to estimate above ground biomass. A decline in mangrove cover (16%) took place between 1969 and 1989 and between 1989 and 2010 an increment was observed in mangrove cover (1452.5 ha in 1989 to 1655.7 ha in 2010). Signs of degradation within the mangrove forest were observed in 2010 in which the degraded land covered 8.8 ha. The total above ground biomass and carbon estimated on the 25 plots was 296.14 ton·ha-1 and 148.07 ton·ha-1 respectively. Mida Creek mangrove forest is largely dominated by the presence of Rhizophora mucronata and Ceriop tagal and the regeneration of these two species is very high. If the present dominance of the two species continues it will affect the species composition of the current mangrove forest. This study recommends a better management plan for the mangrove forest through increasing involvement of the surrounding communities. Furthermore, there should be a way to control selective and illegal cutting of mangroves and promote other species of trees for domestic and commercial use to reduce the high dependency on the use of mangroves for construction purposes.

Physico-Chemistry of Elechi Creek in the Upper Bonny Estuary, Rivers State, Nigeria

The physico-chemistry of tidal Elechi Creek in the upper Bonny Estuary was investigated to assess the toxicity of the water body as this could have adverse effects on the native organisms that form part of the ecosystem and to evaluate the extent and magnitude of petroleum hydrocarbon and heavy metal concentration in the water body. Standard field procedures were adopted in sample collection while laboratory analysis was carried out also following standard methods. Parameters measured include pH, temperature, dissolved oxygen (DO), biological oxygen demand (BOD), electrical conductivity, salinity and total dissolved solids (TDS). Heavy metals namely Copper (Cu), Lead (Pb), Zinc (Zn), nitrate (NO3), sulphate (SO4), Ammonia (NH4), and Total Hydrocarbon Concentration (THC) in the surface water body were also determined on samples collected from five (5) sampling stations spread along the creek in both dry and wet seasons. The results showed that the surface water body is oligohaline with low acidity, pH values ranging from 6.2 to 7.6. Temperature varies from 27&#176C to 30&#176C. Dissolved Oxygen (DO) concentration ranges from 2.9 to 7.5 mg/l which is adequate for aquatic organism with Biological Oxygen Demand (BOD) values varying from 0.45 to 7.0 mg/l. The values of total dissolved solids (TDS) vary from 11,700 mg/l to 26,250 mg/l with the highest mean value obtained at the study station located downstream. The mean nutrient concentration showed that the study area is not eutropic. Anthropogenic activities were very high at the sites throughout the period of the study and may have resulted in the stress conditions of the area. Pollution trend along the study stations showed that no one station is unpolluted. The study recommends the introduction of enforceable and stringent waste management plans to highlight and discourage direct discharge of untreated waste and storm water runoff into an aquatic environment.

Perception Assessment of the Impact of Human Activities on Stubbs Creek Forest Reserve, Akwa Ibom State, Nigeria

Perception assessment of the impacts of human activities on Stubbs Creek Forest Reserve (SCFR) which is located between latitude 4°32'N and 4°40'N and longitude 7°48'E and 8°20'E (Figure 1) distributed into four Local Government Areas-Eket, Esit Eket, Ibeno and Mbo of Akwa Ibom State was carried out. Structural questionnaires to extract the common types of useful plants and animals, status of the protected area, derivable benefits and ways of preserving the SCFR were ministered to Chiefs Priests, Local Chiefs, Elderly People and Farmers who lived at least twenty years in the areas. Convenient sampling method was used to randomly select fifty respondents for the study. Descriptive statistics to summarize feedbacks from respondents presented in the form of tables, charts and histogram in line with the SCFR anthropogenic activities assessment indicators showing percentages and frequencies of such response was employed for data analyses and presentation. The results showed that the Stubbs Creek Forest Reserve have been disturbed and degraded due to uncontrolled human activities. Endangered fauna species including the Giraffa camelopardalis(Giraffe), Hippopotamus amphibious (Hippopotamus), Loxodonta africana (Elephant), Hynas, Kangaroo, Pantherpardus (Leopard), Panther leo (Lion), Porcupine and Tiger were last seen between twenty and thirty five years ago in the forest while some useful plants of huge economic and medicinal values like Irvingia gabonensis(Bush mango) Tetrapleura itraptera, Gambeya albidum, Raphia hookeri (Rafia palm), Garcinia cola (Bitter kola) and Dacryodes edulis (Native pear) etc were last observed about eleven to twenty years ago. The study further revealed that Monkeys and Alligators are still very common in the Forest Reserve. It, therefore, recommends the strengthening and enforcement of regulatory controls on the use of SCFR by relevant authorities and alternative source of firewood to reduce anthropogenic abuses and protect the rich resources of the forest from extinction.

Petrographic Studies on Hydrothermally Altered Conglomerates at Naer Creek, Sichuan Province, China

Based on analysing the wall rock alterations and related rocks which were used as a hint for mineral deposits and as a basis of mechanism research of fluid rock interaction, according to the results of petrographic analysis, the authors of this paper consider that the hydrothermally altered conglomerates have the following features. First, the conglomerates studied can be divided into two groups: Group A consists mainly of the gravels of granite and basalt; Group B is mainly composed of the gravels of basalt, limestone, mudstone and granite. Second, three distinct hydrothermal alterations or diagenesis were distinguished in Group A, that is, pre depositional hydrothermal alteration of the volcanic gravels (saussuritzation chloritization, epidotization chloritization, albitization and sericitization), mechanical diagenesis and post diagenetic hydrothermal alteration (epidote chlorite and prehnite calcite association). Third, the Group B is subjected mainly to pre depositional hydrothermal alteration; the alteration types are the same as of Type A. Last, the origin of the post diagenetic hydrothermal alteration of Group A is presumed to be related to the ascending of thermal water along the Naer Creek fault.

Characterization of Springtime Coliform Populations at the End Creek Wetland Restoration (Union Co., Oregon, USA): A Three-Year Study

In 2005, a 550-acre tract of agricultural land containing two small streams near La Grande, Oregon was registered in the U.S. Federal Wetlands Reserve Program. This designation was part of a plan to reclaim and restore the wetland to its natural state. Initial efforts at the End Creek Restoration Project restored both End Creek and South Fork Willow Creek to a natural course through rechanneling, and several plantings had restored some of the native flora. Since its establishment, the End Creek streams and floodplain have become a reserve for summer steelhead (Oncorhynchus mykiss), a threatened anadromous salmonid, and many migratory birds. The threatened Columbia Spotted Frog has also established itself in some of the ponds. As part of an effort to establish a baseline for water quality, we monitored total springtime coliform and fecal coliform bacteria in three of the End Creek ponds for three years. The results of this study indicate that, throughout any given spring, the numbers of both coliform and fecal coliform bacteria can fluctuate markedly among ponds on any given day, and that in any particular pond the numbers fluctuate from week to week. In addition, our analysis suggests that in early spring, the numbers of these organisms also fluctuate from year to year. The causes of these fluctuations are not well understood, but are expected to reflect both springtime flooding and the migrations of source animals such as waterfowl and cervids. Information gathered from this study will help inform future management activities on the wetland.

Assessment of Physicochemical Characteristics of Sediment from Nwaja Creek, Niger Delta, Nigeria

Sediments are complex environments, with varying physicochemical characteristics, such as composition and type of organic matter, particle size distribution, and pH. Contaminated sediment is a significant environmental problem affecting many marine, estuarine and freshwater environments throughout the world. Most assessments of water quality have historically focused on water-soluble compounds, with relatively little attention paid to sediment. The aim of this research is to assess the physical and chemical parameters of sediments from Nwaja Creek, Niger Delta, Nigeria. Monitoring of this sediment quality is an important part of preserving and restoring the biological integrity of water bodies as well as protecting aquatic life, wild life and human health. Sediment samples from Nwaja Creek were sampled from seven sampling stations along the creek for over three months May to July, 2015, rainfall peak period, for assessment of their physical and chemical characteristics, such as grain size, organic carbon, pH, conductivity, nitrate and phosphate. These parameters are known to influence the interactions and dynamics of pollutants within sediment matrix. Sediment particle size distribution indicates that they have higher proportion of clay (clay > silt > sand), the mean percentage composition of clay, silt and sand ranged between 64.28% ± 22.04% - 72.36% ± 14.00%, 18.71% ± 12.03% - 27.32% ± 22.17% and 8.40% ± 6.28% - 9.76% ± 4.59% respectively. TOC in the study area is generally above 1% across all stations during the study period with a range between 0.98% and 4.58%. Minimal monthly and spatial variations are observed in particle distribution, pH (3.9 - 8.5) and phosphate (5.5 - 15.5 kg/mg) while significant variations are observed in conductivity (23.0 - 567.0 uS/cm), total organic carbon (0.98% - 4.58%) and nitrate (0.45 - 11.9 mg/kg) concentration. It is concluded that physicochemical characteristics of the sediments from Nwaja Creek are influenced by anthropogenic sources rather than natural as shown by the elevated phosphate and nitrate levels because the Niger Delta geology is not essentially rich in nitrate and its excess in surface or groundwater is considered as pollutant.