Depuration of copper and zinc by green oysters and blue mussels of Taiwan

This paper describes depuration processes of copper and zinc in green oysters (Crassostrea gigas) and in blue mussels (Mytilus smarangdium) collected from an environment with heavy copper contamination, and then transferred to natural clean seawater. Results show that the total loss of copper content per oyster is an exponential function of exposure time for the first 6 days with a depuration rate of 351 microg g(-1) day(-1) and then levels off. During this exponential decrease period approximately 67% of the copper accumulated in green oysters was depurated. However, when the copper contents in the oysters decreased from 2225 +/- 111 microg g(-1) to 344 +/- 18.7 microg g(-1) the depuration rates decreased from 245 microg g(-1) day(-1) to 0.08 microg g(-1) day(-1). This means that green oysters had a 16-fold higher copper depuration rate (351 microg g(-1) day(-1)) than normal oysters (21.5 microg g(-1) day(-1)) for the first 6 days. However, the depuration of accumulated copper and zinc by the mussels was a fast process in natural clean seawater. About 91% of the accumulated copper was lost during the first 6-day period; copper contents declined from 20.2 +/- 3.41 microg g(-1) to 1.80 +/- 0.21 microg g(-1). Only 36% of the accumulated zinc was lost during a depuration period of 6 days. Calculations show that the biological half-lives of copper in green and normal oysters were 11.6 and 25.1 days, respectively. The biological half-lives of zinc in green and normal oysters were 16.7 and 30.1 days, respectively. In spite of the relatively low initial copper content in blue mussels being 20.2 +/- 3.41 microg g(-1), the biological half-life is only 6.40 days. From these results it is important to emphasise that the fastest turnover rate is for copper in blue mussels. However, zinc is more retentive in blue mussels than copper.     

Coprostanol distribution in marine sediments off southwestern Taiwan

One of the major industries in southern Taiwan is pigfarming along the Kaoping River; some two million animals are being raised along the river banks. Excretions from pigs, treated and untreated, are discharged directly into the river and eventually carried to the sea. Twenty-four surface sediments and one sediment core off southwestern Taiwan were analyzed to determine quantitatively the extent of coprostanol addition and its distribution and to obtain the input of coprostanol over the past. Geographically, the percent coprostanol is highest around the river mouth, and decreases to about 1% at the shelf break and about 0% at a distance of approximately 40 nautical miles (74 km) from the river mouth. The progressive seaward decline of percent coprostanol from the river mouth can be attributed to [1] dilution of coprostanol by uncontaminated sediment and/or sediment containing relatively lower levels of coprostanol, [2] dilution of coprostanol by biogenic sterols, and [3] probably degradation of coprostanol. Further, the Kaoping Canyon sediments contain relatively high percent coprostanol; this can be attributed to [1] a more direct input of the river sediments because the canyon is well aligned with the river, [2] currents in the canyon being alternate upcanyon and downcanyon which tend to keep sediments in the canyon, and [3] the possible blocking effect of a topographic high in the canyon. A sediment core exhibits comparatively higher percent coprostanol in the top 15 cm, indicating an increased input of coprostanol over the past 20 years.     

Comparison of E. coli, enterococci, and fecal coliform as indicators for brackish water quality assessment.

Escherichia coli (E. coli), enterococci, and fecal coliform data were collected and compared as potential indicators for swimmablility assessment of a brackish waterbody (Lake Pontchartrain, Louisiana). These indicators were measured during lake background conditions, in stormwater runoff (before dilution with lake water), and in the outfall plume within the lake following storm events. Microbial indicator titers associated with suspended particles and lake-bottom sediments were also investigated. Overall reduction rate constants for fecal coliform, E. coli, and enterococci in lake water and sediment were measured and reported. Attachment of microbial indicators to suspended matter and subsequent sedimentation appeared to be a significant fate mechanism. A slower reduction rate of indicator organisms in sediment further suggested that bottom sediment may act as a reservoir for prolonging indicator organism survival and added concern of recontamination of overlaying waters due to potential solids resuspension. Results indicated that enterococci might be a more stable indicator than E. coli and fecal coliform and, consequently, a more conservative indicator under brackish water conditions.     

Detection of p34cdc2- and cyclin B-like proteins in Dunaliella tertiolecta (Chlorophyceae)

p34cdc2 and cyclin B are two key proteins in the eukaryotic cell cycle control machinery. They thus could be important cell cycle markers for studies of environmental effects on cell cycle progression and on growth rate of marine phytoplankton. From July 1993 to March 1995, we used commercially available antibodies to examine the presence of their homologs in a marine phytoplankton species, Dunaliella tertiolecta Butcher. A p34cdc2-like protein was detected on the Western blots, with an apparent molecular mass as expected (34 kDa). Anti-cyclin B detected a protein of 63 kDa, a size similar to that of cyclin B in other organisms. The two proteins decreased from the exponential to the stationary growth phase. As determined on the Western blots, their abundance only changed slightly during the cell cycle, being slightly more abundant prior to cell division. Immunofluorescence performed for a partially synchronized culture showed that the fraction of the cell population that was positively stained by anti-p34cdc2 was highest at the time when the culture was mainly in the late G1 or early S phase, and in the late G2 or early M phase, respectively. The fraction was low when the culture was mainly in the S phase. Although further characterization is required to verify their identities, these two growth phase-related proteins appear to be p34cdc2 and cyclin B homologs, which may be useful in studying the cell cycle and growth rates of phytoplankton.     

冀西北间山盆地区景观格局变化及优化研究——以河北省怀来县为例

景观格局的改变会对区域生态系统功能产生影响,对其格局进行优化调控是维持区域生态系统功能稳定性的重要手段。研究以怀来县为例,通过解译判读1993、2003和2013年3期遥感影像,分析了研究区景观格局特征,发现研究区景观破碎化程度呈上升趋势,结合各景观类型在地形位上的分布特征和生态系统服务功能,运用最小累积阻力模型构建了生态源地、生态廊道和生态节点等景观组分,整体连通性指数（dIIC）和可能连通性指数（dPC）评价结果表明河流交汇处及水库周边等区域对景观连通性重要值最大,然后划分了景观生态维持区、景观生态恢复区、景观生态功能强化区和景观生态功能保护区,为该地区景观生态优化提供指导 借鉴。     

Memory effect on the dioxin emissions from municipal waste incinerator in Taiwan

Evaluation of the dioxin removal efficiency of the air pollution control device (APCD) at an existing municipal waste incinerator (MWI) located in Taiwan is conducted via stack sampling and analysis. The MWI investigated is equipped with cyclones, dry lime scrubbing systems and fabric filters as APCDs. Results indicate that the patterns of dioxin isomers at APCDs' inlet and stack are similar. During the first year of carbon injection, the concentrations of emitted dioxin decreased greatly. The dioxin removal efficiency increased from 26.9% to 96.6% after injecting 115 kg/day activated carbon (AC). At the second year, the dioxin removal efficiency reaches 98.7% after injecting the same rate of AC continuously. The lower efficiency achieved with activated carbon injection (ACI) during the first year can be attributed to the memory effect, i.e. the dioxin or precursor desorbs slowly to the flue gas and increases the dioxin concentration at stack, resulting in a lower dioxin removal efficiency than expected.     

Distribution Of Volatile Organic Compounds In Ambient Air Of Kaohsiung, Taiwan

Automobile emissions have created a major hydrocarbon pollution problem in the ambient air of Taiwan. The aim of this study was to determine the volatile organic compounds (VOCs) in the ambient air of Kaohsiung, Taiwan. The spatial distribution, temporal variation, and correlations of VOCs at three study sites, selected based on traffic densities and distances from a freeway, were discussed. Sixty-four hydrocarbons were identified in the ambient air. Among all of the VOC species, acetone, aromatic and aliphatic compounds constituted the major constituents. Higher concentrations of VOCs existed further away from major arteries as compared to those found near the freeway. Therefore, the distance from the freeway may not be a sufficient index for reflecting actual air quality in the study area. Weather conditions, wind speed and direction did not affect the distribution of VOC concentrations in the three study sites. Other factors, such as the height and density of buildings, traffic conditions or commercial activities, might affect the distribution of VOCs.     

Technique for aerosol generation with controllable micrometer size distribution

The purpose of this study is to develop an aerosol generating system that can produce particles of micrometer size in a convenient and efficient way. This system is comprised of an ultrasonic atomizer, potassium sodium tartrate tetrahydrate (PST) as solute and a program-controlled solute feeding unit with different PST concentrations. Both the aerosol concentration and size distribution pattern can be easily controlled and reproduced in the developed system. While the initial size of droplets generated from atomizer may remain unchanged, the size of residual dry aerosols was controlled by the solute concentration adjusted by the mixing ratio of solute and water. In addition, PST concentration could be alternatively adjusted in any cyclic way to provide particles with relatively mono-disperse, bimodal, varying size as well as skew distribution to meet requirements for various applications. The main advantage of the generating system is to generate particles of specific size distribution in order to simulate aerosols in ambient air or working places.     

The interfacial mass transfer resistances of the ozone dry deposition over the field soil of Taichung County in Taiwan

This study aims to design a dry deposition chamber and to measure ozone depletion over the Taichung field soil. This study seeks to verify the phenomena by an experimental and mathematical model. It is demonstrated that interfacial mass transfer resistances of ozone dry deposition involve reactive resistance (R(sr)) and kinetic resistance (R(sk)). It reveals the chemical reaction (O3 + NO --> NO2) to produce the reactive resistance, and verifies that the interfacial mass transfer resistances depend on nitrogen oxide emission and soil temperature. It shows that the interfacial mass transfer resistances are reduced with increasing soil temperature (T(S)). The model profiles are smaller than the observed data within a relative error of 15%. The reactive resistance decreases exponentially with increasing soil temperature; R(sr)(-1) (cm x sec(-1)) = 0.0001 exp (0.1455T(S)). The kinetic resistance decreases linearly with increasing soil temperature; R(sk)(-1)(cm x sec(-1)) = 0.0108T(S) + 1.4012. This model is more accurate with higher soil temperature and larger ozone concentration. Results are consistent with thermodynamics and reaction kinetics. Ozone dry deposition over agricultural soil causes conversion of nitrogen oxide (NO) to nitrogen dioxide (NO2).     

渤海海冰作为淡水资源：脱盐机理与可利用价值

我国北部沿海地区缺水问题十分严重,但冬季在渤海及黄海北部形成较大范围的海冰。海冰因其成冰过程中盐分大量析出而盐度很低,可能成为解决这些地区缺水问题的重要淡水资源。论文根据实地观测和室内不同盐度海水的实验分析,阐述了渤海海冰盐度变化和海水成冰脱盐过程,并采用二次成冰脱盐和离心脱盐等方法,分析了海冰经进一步人工淡化的可能性,探讨了海冰作为淡水资源的可利用价值。