Antifouling paint booster biocides in the UK coastal environment and potential risks of biological effects   总被引：5，自引：0，他引：5  

Thomas KV  Fileman TW  Readman JW  Waldock MJ 《Marine pollution bulletin》2001,42(8):677-688

In the yachting sector of the UK antifouling market, organic biocides are commonly added to antifouling preparations to boost performance. Few data presently exist for concentrations of these compounds in UK waters. In this study the concentrations of tributyltin (TBT) and eight booster biocides were measured before and during the 1998 yachting season. The Crouch Estuary, Essex, Sutton Harbour, Plymouth and Southampton Water were chosen as representative study sites for comparison with previous surveys of TBT concentrations. Diuron and Irgarol 1051 were the only organic booster biocides found at concentrations above the limits of detection. Diuron was measured at the highest concentrations, whilst detectable concentrations of both Irgarol 1051 and diuron were determined in areas of high yachting activity (e.g. mooring areas and marinas). Maximum measured values were 1,421 and 6,740 ng/l, respectively. Lower concentrations of both compounds were found in open estuarine areas, although non-antifouling contributions of diuron may contribute to the overall inputs to estuarine systems. TBT was found to be below or near the environmental quality standard (EQS) of 2 ng/l for all samples collected from estuarine areas frequented by pleasure craft alone, but with much higher concentrations measured in some marinas, harbours and in areas frequented by large commercial vessels. Using the limited published environmental fate and toxicity data available for antifouling booster biocides, a comparative assessment to evaluate the risk posed by these compounds to the aquatic environment is described. TBT still exceeds risk quotients by the greatest margins, but widespread effects due to Irgarol 1051 and less so diuron cannot be ruled out (particularly if use patterns change) and more information is required to provide a robust risk assessment.  相似文献   

Some effects of human modifications on sand-bed channels in southwestern Mississippi,U.S.A.     

Richard H. Kesel  Elaine G. Yodis 《Environmental Geology》1992,20(2):93-104

This study examines the effects of land-use changes and channel foreshortening on the sediment regime and channel morphology of two sand-bed rivers in southwestern Mississippi. Historical data including sequences of channel surveys at various bridge sites document the impact of these human modifications. Land-use changes caused an increase in point bar size, but this trend was found to be reversed as the result of conservation and reforestation practices. Channel foreshortening has produced a knickpoint that has migrated 50 km upriver. River response to this disturbance included 5 m of channel incision, a 4.5-fold increase in bankfull width, and a fourfold increase in point bar size.  相似文献   

Mercury exposure through fish consumption in the urban area of Alta Floresta in the Amazon Basin     

Sandra Hacon  Elaine R.R. Rochedo  Reinaldo R.R. Campos  Luis Drude Lacerda 《Journal of Geochemical Exploration》1997,58(2-3)

This work addresses the mercury exposure scenarios through fish consumption in the urban area of Alta Floresta, by comparing the different patterns of mercury exposure from fish ingestion for different population groups. This study was based on field surveys that could provide background information, such as the characteristics of Hg sources, characteristics of local and regional environment, Hg concentrations in different media, and the characterization of the local urban population. The urban area of Alta Floresta is one of the most important gold-trading centers in Amazonia, where approximately 1 ton of gold has been commercialized monthly. The general adult urban population is exposed to low-level mercury concentration via fish consumption with an average daily intake of 0.2 μg/kg (b.w.) and an estimated hazard quotient of 0.7. However, the fishermen families present an average daily intake of 2.2 μg/kg (b.w.) and a hazard quotient of 8.6. The children of fishermen families between 5 and 14 years old are the main risk group for Hg exposure via fish ingestion. Based on the uncertainty analysis, the Hg fish concentrations and the fish ingestion rate were found to be the main parameters affecting the variability of the model outputs.  相似文献   

Monitoring the Marine Environment     

Douglas A. Segar  Elaine Stamman 《Marine pollution bulletin》1984,15(1):36

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Photographic spectrophotometry of selected bright B and Be Stars     

Elaine M. Hendry  J. D. R. Bahng 《Journal of Astrophysics and Astronomy》1981,2(2):141-159

Coudé spectra taken in the red region of 49 bright B and Be stars were examined for the behaviour of Hα and the He I λλ 5876 and 6678 line profiles. 51 per cent of the stars were found to show Hα emission to some degree and 22 per cent showed helium emission. Evidence is presented for the existence of drastic changes in the line profile and the radial velocity in some of the stars on a time scale of fractions of a day. Visiting Astronomer, Kitt Peak National Observatory and Cerro Tololo Inter-American Observatory, operated by the Association of Universities for Research in Astronomy, under contract with the National Science Foundation.  相似文献   

NIST RM 8301 Boron Isotopes in Marine Carbonate (Simulated Coral and Foraminifera Solutions): Inter‐laboratory δ11B and Trace Element Ratio Value Assignment     

Joseph A. Stewart  Steven J. Christopher  John R. Kucklick  Louise Bordier  Thomas B. Chalk  Arnaud Dapoigny  Eric Douville  Gavin L. Foster  William R. Gray  Rosanna Greenop  Marcus Gutjahr  Freya Hemsing  Michael J. Henehan  Philip Holdship  Yu‐Te Hsieh  Ana Kolevica  Yen‐Po Lin  Elaine M. Mawbey  James W. B. Rae  Laura F. Robinson  Rachael Shuttleworth  Chen‐Feng You  Shuang Zhang  Russell D. Day 《Geostandards and Geoanalytical Research》2021,45(1):77-96

The boron isotopic ratio of ¹¹B/¹⁰B (δ¹¹B_SRM951) and trace element composition of marine carbonates are key proxies for understanding carbon cycling (pH) and palaeoceanographic change. However, method validation and comparability of results between laboratories requires carbonate reference materials. Here, we report results of an inter‐laboratory comparison study to both assign δ¹¹B_SRM951 and trace element compositions to new synthetic marine carbonate reference materials (RMs), NIST RM 8301 (Coral) and NIST RM 8301 (Foram) and to assess the variance of data among laboratories. Non‐certified reference values and expanded 95% uncertainties for δ¹¹B_SRM951 in NIST RM 8301 (Coral) (+24.17‰ ± 0.18‰) and NIST RM 8301 (Foram) (+14.51‰ ± 0.17‰) solutions were assigned by consensus approach using inter‐laboratory data. Differences reported among laboratories were considerably smaller than some previous inter‐laboratory comparisons, yet discrepancies could still lead to large differences in calculated seawater pH. Similarly, variability in reported trace element information among laboratories (e.g., Mg/Ca ± 5% RSD) was often greater than within a single laboratory (e.g., Mg/Ca < 2%). Such differences potentially alter proxy‐reconstructed seawater temperature by more than 2 °C. These now well‐characterised solutions are useful reference materials to help the palaeoceanographic community build a comprehensive view of past ocean changes.  相似文献   

Organic and soil material between tills in east-midland England – direct evidence for two episodes of lowland glaciation in Britain during the Middle Pleistocene     

James Rose  Jenni Turner  Elaine Turton  James B. Riding  Adrian Palmer  John K. Wright  Jonathan R. Lee  Nicholas S. J. Q. Bullimore 《第四纪科学杂志》2021,36(4):547-569

This paper provides a record and analysis of a site in east-midland England, at which organic and soil material are found between two Middle Pleistocene tills. This is the first discovery of its kind in the area, and demonstrates unequivocally that the region was glaciated on two separate occasions, something that has long been inferred and articulated, but not actually demonstrated. The landforms, sediments and soils are studied with respect to their geomorphological, lithological, pedological, palaeobotanical and structural properties. The organic and soil material along with soil structures indicate, sequentially, a periglacial climate, a long period of warm temperate weathering and a cool temperate climate. Evaluation of this evidence in terms of existing published work identifies a number of problems with existing models and suggests that the most likely model for the glacial history of this part of midland England is an early Middle Pleistocene glaciation which is represented only by trace erratics, a Marine Isotope Stage (MIS) 12 age glaciation which moved across the area from the NW and deposited a chalk-free till, and an MIS 8 age glaciation that transported and deposited an upper chalky till from the NE. © 2021 The Authors. Journal of Quaternary Science Published by John Wiley & Sons Ltd.  相似文献   

Migration‐as‐development repackaged? The globalizing imperative of the Singaporean state's diaspora strategies          下载免费PDF全文

Elaine Lynn‐Ee Ho  Mark Boyle 《Singapore journal of tropical geography》2015,36(2):164-182

Diaspora strategizing is becoming an important field of public policy in countries that seek to advance development through migration. Diaspora strategies present a way of complicating interpretations of development, as countries that represent different levels of development seek to mobilize diaspora networks nonetheless. While Singapore's diaspora strategies prioritize diaspora knowledge networks, it bears the stamp of the country's colonial history, postcolonial priorities and developmental state apparatus. We suggest that these factors result in a distinctive diaspora strategy characterized by a centralized and technocratic approach more similar to diaspora strategies found in emerging economies. Earlier research on diaspora strategies has been concerned with assessing successes or failures, but a more critical scholarship that questions the logics and outcomes of diaspora strategizing is emerging. We bring the Singaporean case into dialogue with four such critiques: first, the intellectual foundations of diaspora‐centred development; second, the hyperextension of state infrastructure for emigration and stakeholder alignment; third, the selective mobilization of the idea of diaspora; and fourth, the evidence base upon which diaspora‐centred development is predicated. Our goal is to further critical interrogation into the logics, efficacy and sustainability of diaspora strategizing. We situate our analyses in the international literature on diaspora knowledge mobilization.  相似文献   

Fracture-frequency prediction from borehole wireline logs using artificial neural networks     

Elaine M. FitzGerald  Christopher J. Bean  & Ronan Reilly 《Geophysical Prospecting》1999,47(6):1031-1044

Borehole-wall imaging is currently the most reliable means of mapping discontinuities within boreholes. As these imaging techniques are expensive and thus not always included in a logging run, a method of predicting fracture frequency directly from traditional logging tool responses would be very useful and cost effective. Artificial neural networks (ANNs) show great potential in this area. ANNs are computational systems that attempt to mimic natural biological neural networks. They have the ability to recognize patterns and develop their own generalizations about a given data set. Neural networks are trained on data sets for which the solution is known and tested on data not previously seen in order to validate the network result. We show that artificial neural networks, due to their pattern recognition capabilities, are able to assess the signal strength of fracture-related heterogeneity in a borehole log and thus fracture frequency within a borehole. A combination of wireline logs (neutron porosity, bulk density, P-sonic, S-sonic, deep resistivity and shallow resistivity) were used as input parameters to the ANN. Fracture frequency calculated from borehole televiewer data was used as the single output parameter. The ANN was trained using a back-propagation algorithm with a momentum learning function. In addition to fracture frequency within a single borehole, an ANN trained on a subset of boreholes in an area could be used for prediction over the entire set of boreholes, thus allowing the lateral correlation of fracture zones.  相似文献   

Techniques for the Determination of Cyanide in a Process Environment: A Review   总被引：1，自引：0，他引：1  

Deon E. Barnes  Peter J. Wright  Sandra M. Graham  Elaine A. Jones-Watson 《Geostandards and Geoanalytical Research》2000,24(2):183-195

The determination of cyanide in various forms is important for industrial processes as well as for environmental investigations and monitoring associated with these processes. The accurate determination of cyanide is difficult for various reasons. Depending on the pH of the solution, cyanide is present both in molecular form (HCN) and ionic form (CN). Furthermore, cyanide is a good complexing reagent and reacts with almost all cations resulting in complexes with widely varying properties, such as stabilities, solubilities and rates of reaction. Cyanide also breaks down in sunlight and air, so that sampling and sample treatment become very important aspects to consider in the methodologies. During the last fifty years the determination of cyanide has been approached from various angles and a myriad of methods has been developed for its determination. This study represents a survey of methods commonly used in industrial laboratories for the analysis of cyanide-containing solutions. An overview of the nomenclature often used for the various forms of cyanides is discussed and the values resulting from a particular analysis will be interpreted. Most common interferences in samples originating from gold processing plants will be discussed.  相似文献