Metal diffusion properties of a Nafion-coated porous membrane in an aquatic passive sampler system

A cellulose acetate membrane, positioned in a passive sampler system, was coated with the perfluorinated polymer Nafion. Aqueous metal transport through the membrane and the Nafion film was investigated. The Nafion-coated membrane prevents the transport of metals bound to natural organic material to the receiving phase in the passive sampler, while copper associated with small synthetic ligands pass through the Nafion film. Increasing thickness of the Nafion film decreases the metal uptake rate to the receiving phase in the passive sampler and increases the response time. A decreased response time for the passive sampler would provide a better estimation of rapid changes in concentration, particularly for dynamic aquatic systems such as urban runoff. Limited biofouling protection with the Nafion coating was demonstrated by growth inhibition of natural periphyton communities on glass surfaces.     

QUANTIFICATION FOR VISUALIZATION OF TIME TREND1

ABSTRACT: A method for quantifying fluctuations in time-series data was developed and tested to aid the process of visualization. The methodology is based on free-form sliding polynomials and identifies (a) short-period variability about the mean value, (b) a long-term trend or cycle, and (c) random errors residual to these two structured components. Consistent results were obtained for designed synthetic data and natural data from seven sites in Georgia. Statistics of fit of the analytical model for the natural data were not significant on a site-by-site basis. An unexpected finding for the study was obtained when the statistical results for the seven data sets for temperature were pooled. The smoothing model yielded consistent long-term trends even though the individual station results were not significant. Also, the correlation coefficients, while low, showed a statistically significant trend toward higher values toward the northwest and away from the Georgia coast line. This study thus supports the concept that multiple-site, and regionally based, analyses are necessary for the detection of trends. Secondarily, such consistency of results strengthens the conclusion that the proposed smoothing method is an effective procedure in the presence of varying amounts of random content in the natural data sets.     

WATER BALANCE AT A LOW-LEVEL RADIOACTIVE-WASTE DISPOSAL SITE1

ABSTRACT: The water balance at a low-level radioactive-waste disposal site in northwestern Illinois was studied from July 1982 through June 1984. Continuous data collection allowed estimates to be made for each component of the water-balance equation independent of other components. The average annual precipitation was 948 millimeters. Average annual evapotranspiration was estimated at 637 millimeters, runoff was 160 millimeters, change in water storage in a waste-trench cover was 24 millimeters, and deep percolation was 208 millimeters. The magnitude of the difference between precipitation and all other components (81 millimeters per year) indicates that, in a similar environment, the water-budget method would be useful in estimating evapotranspiration, but questionable for estimation of other components. Precipitation depth and temporal distribution had a very strong effect on all other components of the water-balance equation. Due to the variability of precipitation from year to year, it appears that two years of data are inadequate for characterization of the long-term average water balance at the site.     

Edge Effects and Isolation: Red-Backed Voles on Forest Remnants

Negative effects of habitat edge have been advanced as an important proximate cause of extinction, and a growing literature calls attention to the matrix surrounding habitat remnants as a critical factor determining population persistence. I examined spatial distribution of California red-backed voles ( Clethrionomys californicus ) on 13 forest remnants and five control sites in southwestern Oregon. The species was virtually isolated on remnants, making little use of the regenerating clearcuts surrounding the remnants. The effects of the clearcut also impinged on the remnants as edge effects: six times more voles were captured per trap in the interior of remnants than on the edge. Consequently, the density of voles per unit area on remnants increased with remnant size, despite the potential buildup of population density in small isolates due to limited emigration. I explored potential mechanisms of the negative edge effect on voles and found that the biomass of coarse woody debris, per se, did not explain the vole distribution because both number and volume of logs increased from the interior to the edge of remnants. However, the distribution of the vole's primary food item, hypogeous sporocarps of mycorrhizal fungi, did correspond to the vole edge effect     

Phenological weighting of ozone exposures in the calculation of critical levels for wheat, bean and plantain

This paper presents phenological weighting factors to be applied to AOT40 (accumulated ozone exposure above a threshold of 40 nl l(-1)) ozone exposure-response relationships for crops at different growth stages. The quantification of such factors represents a step-forward in the derivation of Level II critical levels for ozone. The weighting factors presented are derived from published literature on the sensitivity of wheat (Triticum aestivum), bean (Phaseolus vulgaris) and plantain (Plantago major) to ozone at different growth stages. Weighting functions were calculated using either multiple linear regression or the reciprocal residual mean square (RMS(-1)). The resulting weights were transformed into multiplication factors to be applied to the monthly AOT40 during the 3-month assessment period of critical level exceedance. Interspecific differences were too large to allow for the development of a unified weighting function for the three species considered. For wheat grain yield, the derived multiplication factors varied by almost four-fold (0.40, 1.06, 1.54), while those for bean pod yield varied by only about 25% (0.85, 1.01, 1.14). The available data for plantain were restricted to short-term studies conducted under controlled conditions. These data were not suitable for the derivation of weighting factors comparable to those derived for bean and wheat. Based on known differences in wheat development and phenology across Europe, the need for a geographic differentiation of the time period for the calculation of the critical level exceedances is also discussed and examples provided of the adoption of the derived weightings in the mapping of critical level exceedances. Differences between critical level exceedance maps using weighted and unweighted AOT40 calculations are discussed.     

青岛理工大学安全工程专业课程体系设置模式

介绍了我国安全工程专业发展概况、存在的问题及青岛理工大学安全工程专业现状.重点介绍了青岛理工大学安全工程专业课程体系设置情况,提出了2006年安全工程专业课程体系设置调整的构想.     

The Student Volunteer Army: a ‘repeat emergent’ emergency response organisation

This paper seeks to contribute to understanding of the factors associated with an effective emergent emergency response organisation and to provide new insights into this understudied area. It examines, through an analysis of a range of textual resources, the emergence and re‐emergence of the Student Volunteer Army (SVA) during the devastating earthquakes in Canterbury, New Zealand, in 2010–11. This evaluation is conducted in relation to the four key features of an effective emergency response organisation: adaptability; direction; leadership; and communication. In addition, the paper aims to further understanding of ‘emergency entrepreneurship’ and thus of the values and strategies that underpin social entrepreneur organisations in times of normalcy. The paper concludes that the unique position of the SVA as a ‘repeat emergent’ emergency response organisation enabled it to innovate continually and to improve repeatedly its systems, relationships, and image, such that it exhibited features common to emergent and established emergency response organisations.     

The development and application of remote sensing to monitor sand dune habitats

Sand dunes are complex systems that contain several habitats, often as mosaics or transitions between types. Several of these habitats are afforded protection under European Legislation and in the UK nationally within Special Areas of Conservation (SAC) and Sites of Special Scientific Interest (SSSI). Natural England has a statutory duty to report to Europe on the conservation status and condition of sand dunes; and is required to report to the UK Government on designated sites. To achieve this we have sought ways of capturing, analysing and interpreting data on the extent and location of sand dune habitats. This requires an ability to be able to obtain data over large areas of coastline in an efficient way. Natural England and Environment Agency Geomatics have worked collaboratively for over 16 years, sharing data and ecological knowledge. In 2012 work started to evaluate the use of remote sensing to map UK BAP and Annex I sand dune habitats. A methodology has now been developed and tested to map sand dune habitats. The key objective was to provide an operational tool that will help to map these habitats and understand change on sites around England. This has been achieved through analysis of LIDAR and Compact Airborne Spectrographic Imager (CASI) data using Object Orientated Image Analysis. Quality Control (QC) and accuracy assessments have shown this approach to be successful and 11 sites have been mapped to date. These techniques are providing a new approach to monitoring change in coastal vegetation communities and informing management of protected sites.     

利用彗星实验检测丙烯酰胺对小鼠两种细胞的DNA损伤和修复

为了研究丙烯酰胺致小鼠睾丸细胞和外周血淋巴细胞DNA的损伤及修复情况,同时比较这两种细胞对丙烯酰胺的敏感性,将雄性昆明种小鼠一次性腹腔注射丙烯酰胺(50mg·kg-1(bw)),在暴露后第1、2、4、6、8、10、12d,分别对其睾丸组织细胞和外周血淋巴细胞DNA损伤进行彗星实验分析.结果表明,暴露结束后每个时间点小鼠睾丸组织细胞、外周血淋巴细胞DNA的迁移率均显著高于阴性对照组,随时间推移两种细胞DNA迁移距离逐渐降低,同一时间点睾丸组织细胞DNA损伤较外周血淋巴细胞DNA损伤更为严重,两者差异显著(p<0.05).以上结果表明,睾丸组织和外周血淋巴细胞可能是丙烯酰胺的作用位点;机体对丙烯酰胺造成的遗传损伤有一定的修复能力;与淋巴细胞相比,睾丸细胞对丙烯酰胺导致的遗传损伤更为敏感.     

Abiotic transformation of estrogens in synthetic municipal wastewater: An alternative for treatment?

The abiotic transformation of estrogens, including estrone (E1), estradiol (E2), estriol (E3) and ethinylestradiol (EE2), in the presence of model vegetable matter was confirmed in this study. Batch experiments were performed to model the catalytic conversion of E1, E2, E3 and EE2 in synthetic wastewater. Greater than 80% reduction in the parent compounds was achieved for each target chemical after 72 h with the remaining concentration distributed between aqueous and solid phases as follows: 13% and 7% for E1, 10% and 2% for E2, 6% and 2% for E3, and 8% and 3% for EE2, respectively. Testosterone, androstenedione and progesterone were also monitored in this study, and their concentrations were found to be in agreement with initially spiked amount. Data collected under laboratory conditions provided the basis for implementing new abiotic wastewater treatment technologies that use inexpensive materials.