Dichloromethane Marine Risk Assessment with Special Reference to the Osparcom Region: North Sea

This risk assessment on dichloromethane was carried out specifically for the marine environment, following methodology given in the EU risk assessment Regulation (1488/94) and Guidance Document of the EU New and Existing Substances Regulation (TGD, 1997). The study consists of collection and evaluation of data on effects and environmental concentrations from analytical monitoring programs in large rivers and estuaries in the North Sea area. The risk is indicated by the ratio of 'predicted environmental concentrations' (PEC) to 'predicted no-effect concentrations' (PNEC) for the marine aquatic environment. In total, 23 studies for fish, 17 studies for invertebrates and 6 studies for algae were evaluated. Both acute and chronic toxicity studies were taken into account and appropriate assessment factors used to define a PNEC value of 830 microg/l. Most of the available monitoring data apply to rivers and estuaries and were used to calculate PECs. The most recent data (1983--1995) support a typical PEC for dichloromethane lower than 0.2 microg/l and a worst case PEC of 13.6 microg/l. Dichloromethane is not a 'toxic, persistent and liable to bioaccumulate' substance sensu the Oslo and Paris Conventions for the Prevention of Marine Pollution (OSPAR-DYNAMEC). The calculated PEC/PNEC ratios give margins of 60 to 4000 between the PNEC and PEC, dilution within the sea would further increase these margins. It can be concluded that the present use of dichloromethane does not present a risk to the marine aquatic environment.     

Seasonal effects on the air-water carbon dioxide exchange in the Hooghly estuary,NE coast of Bay of Bengal,India

Monthly variation of CO2 fugacity (fCO2) in surface water and related atmospheric exchanges were measured in the Hooghly estuary which is one of the most important estuaries, since it is fed by one of the world's largest rivers, the Ganges with a flow of 15,646 m3 s-1 (1.6% of the world's combined river flow). Carbon dioxide fluxes averaged over the entire estuary are in the range of -2.78 to 84.4 mmol m-2 d-1. This estuary acts as a sink for CO2 during monsoon months and seasonal variation of its flux is controlled by dilution of seawater by river water. Since the solubility of CO2 and the disassociation of carbonic acid in estuarine water are controlled by temperature and salinity, the observed variations of CO2 fluxes are compared with those predicted from seasonal changes in temperature, salinity and the ratio of gross primary production to community respiration using empirical equations with an explained variability of 55%.     

Histological and biochemical bases of defense mechanisms in four species of Polybranchioidea ascoglossan molluscs

The multiple defensive strategies of four Mediterranean ascoglossan molluscan species, belonging to two different Polybranchioidea families, Cyerce cristallina (Trinchese, 1881) and Caliphylla mediterranea (Costa A., 1869) (Polybranchiidae), and Ercolania funerea (Costa A., 1867) and Placida dendritica (Alder and Hancock, 1843) (Stiligeridae), were studied. E. funerea, P. dendritica and C. mediterranea were collected from the lake Fusaro (Arco Felice, Naples) in 1992. C. cristallina was collected from Capo Miseno (Bay of Naples) in 1991. C. cristallina and E. funerea easily undergo autotomy of dorso-lateral appendages (cerata) followed by an extraordinarily quick (8 to 10 d) regeneration of the latter. Histological analyses showed the presence, at the basis of both normal and regenerated cerata of these species, of a muscular sphincter which facilitates the autotomic process. C. mediterranea and P. dendritica, which do not undergo autotomy, lack this anatomical feature but feed upon algae belonging to the Chaetomorpha and Bryopsis genera, and, as shown by electron microscopy studies, retain large quantities of chloroplasts which they use as camouflage amidst algae and to escape predation. E. funerea also exploits this behavioral defense mechanism. Histological investigations also revealed in the cerata of all four species several multi-cellular mucous glands responsible for the secretion of the slime typical for these molluscs. C. cristallina, E. funerea and P. dendritica secrete large amounts of slime, whose extracts displayed ichthyotoxic activity when assayed by the Gambusia affinis ichthyotoxicity assay, while extracts of C. mediterranea slime were not toxic. A chemical analysis of the slime, mantle and cerata led to the isolation of polypropionate - and -pyrones from all species except C. mediterranea. These secondary metabolites possess structures that differ only by the degree of methylation and the geometry of double bonds of the side chain and are specifically distributed in cerata and slime of C. cristallina and E. funerea. The pyrones also display different activities in the Hydra vulgaris regeneration assay and in the G. affinis ichthyotoxicity test and, depending on their structural features and tissue distribution, are likely to play a role either as defense allomones or as supportive inducers of cerata regeneration. In conclusion, combined biological observations and histological and chemical techniques generated valuable information on the defensive behavior of these four ascoglossan species which exploit various combinations of the same behavioral and/or chemical defensive strategies and thus successfully avoid predation.     

水生植物在滇池湿地景观设计中的应用

以滇池湿地景观设计为研究对象,介绍了水生植物在湿地景观设计中的作用和原则以及水生植物的选择、配置和生物浮岛技术的运用.     

Linking the Big Five‐Factors of personality to charismatic and transactional leadership; perceived dynamic work environment as a moderator

In this multi‐source study we investigated the relationships between the Big Five personality traits and both charismatic and transactional leadership behavior, and whether dynamism (the degree that the work environment is deemed dynamic) moderates these relationships. We also tested whether dynamism moderates the relationship between leadership behavior and effectiveness. Personality was measured through self ratings using the NEO‐PI‐R. Subordinates rated their leaders' behavior, and peers and superiors provided ratings of effectiveness. Consistent with trait activation theory, results showed that perceived dynamic work environment moderated the relationships of four of the Big Five‐Factors with both charismatic and transactional leadership. Also, charismatic leadership was positively related to perceived effectiveness, but only in dynamic contexts. Copyright © 2005 John Wiley & Sons, Ltd.     

Where intrinsic job satisfaction fails to work: national moderators of intrinsic motivation

This study sought for national characteristics that moderate the individual‐level relationship between job characteristics and job satisfaction. Data from two distinct questionnaire surveys administered to 107,292 employees in 49 countries was analyzed by employing multilevel modeling. Results showed that the link between intrinsic job characteristics and job satisfaction is stronger in richer countries, countries with better governmental social welfare programs, more individualistic countries, and smaller power distance countries. By contrast, extrinsic job characteristics are strongly and positively related to job satisfaction in all countries. In addition, we found that intrinsic job characteristics tend to produce motivating satisfaction in countries with good governmental social welfare programs irrespective of the degree of power distance, while they do not tend to work so in countries with poor governmental social welfare programs as well as a large power distance culture. Socio‐economic and cultural approaches to explaining cross‐national variation in work motivation are discussed. Copyright © 2003 John Wiley & Sons, Ltd.     

A numerical study of soil cover performance

In the investigation of soil cover design options for final decommissioning of reactive mine waste, it is often necessary to analyze or predict the anticipated cover performance as a function of the cost of implementation, which is governed by the type, number and thickness of the layers in the cover system. An example of such investigation is presented in this study where one-dimensional evaporation from hypothetical moisture-retaining cover systems is simulated to assess the influence of several cover properties and hydrogeologic parameters on performance. The commercially available transient flow model, SoilCover, was used to compute suction and water content profiles for different cover design scenarios. The predicted water content profile and porosity of layers were then used to estimate the oxygen diffusion coefficients of the various layers. The oxygen diffusion coefficients were used to estimate oxygen flux through the cover systems. The oxygen flux was, in turn, related to the maximum acid flux. The studied cover and hydrogeologic parameters included soil type, thickness of barriers, and water table elevation. Two types of infiltration and oxygen barrier and two types of capillary layer with different thicknesses were studied. The water table was either kept constant at the base of the waste (tailings) or dropped by 0.5, 1, 2, and 3m over 120 days. The results showed that the relationship between water table depression and the thickness of capillary layers, on one hand, and desaturation of the infiltration and oxygen barrier, on the other, is not linear. Relationships between oxygen flux and barrier thickness and between cost increase and performance improvement of the studied cover systems are presented. Finally, a method that outlines steps for site-specific and economically feasible design of multi-layer cover systems is introduced.     

An instrumented station for the survey of ozone and climate change in the southern tropics

The assessment of changes induced by human activities on Earth atmospheric composition and thus on global climate requires a long-term and regular survey of the stratospheric and tropospheric atmospheric layers. The objective of this paper is to describe the atmospheric observations performed continuously at Reunion Island (55.5 degrees east, 20.8 degrees south) for 15 years. The various instruments contributing to the systematic observations are described as well as the measured parameters, the accuracy and the database. The LiDAR systems give profiles of temperature, aerosols and ozone in the troposphere and stratosphere, probes give profiles of temperature, ozone and relative humidity, radiometers and spectrometers give stratospheric and tropospheric integrated columns of a variety of atmospheric trace gases. Data are included in international networks, and used for satellite validation. Moreover, some scientific activities for which this station offers exceptional opportunities are highlighted, especially air mass exchanges nearby dynamical barriers: (1) On the vertical scale through the tropical tropopause layer (stratosphere-troposphere exchange). (2) On the quasi-horizontal scale across the southern subtropical barrier separating the tropical stratospheric reservoir from mid- and high latitudes.     

Biological stability assessment of MSW organic fractions by means of respirometric and germination tests

Journal of Material Cycles and Waste Management - Composting is the mostly applied method for recovering the organic waste by producing an organic soil conditioner. Furthermore, the organic...