Sedimenttoxizit?t — ein inhaltlicher Schwerpunkt beim SETAC Europe 16th Annual Meeting World Forum Convention Center in Den Haag, Niederlangden, 7–11 Mai 2006

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Sedimenttoxizit?t — ein inhaltlicher Schwerpunkt beim SETAC Europe 16th Annual Meeting World Forum Convention Center in Den Haag, Niederlangden, 7–11 Mai 2006     

Research on simultaneous impact of hand-arm and whole-body vibration

This article presents the results of laboratory tests on the combined effect of whole-body vibration (WBV) and hand-arm vibration (HAV). The reactions of subjects exposed to various combinations of vibration were recorded. The vibrotactile perception threshold (VPT) test identified changes caused by exposure to vibration. Ten male subjects met the criteria of the study. There were 4 series of tests: a reference test and tests after exposure to HAV, WBV, and after simultaneous exposure to HAV and WBV. An analysis of the results (6000 ascending and descending VPTs) showed that the changes in VPTs were greatest after simultaneous exposure to both kinds of vibration. The increase in VPT, for all stimulus frequencies, was then higher than after exposure to HAV or WBV only.     

Self-assessment of hearing status and risk of noise-induced hearing loss in workers in a rolling stock plant

Noise measurements and questionnaire inquiries were carried out for 124 workers of a rolling stock plant to develop a hearing conservation program. On the basis of that data, the risk of noise-induced hearing loss (NIHL) was evaluated. Additionally, the workers' hearing ability was assessed with the (modified) Amsterdam inventory for auditory disability and handicap, (m)AIADH. The workers had been exposed to noise at A-weighted daily noise exposure levels of 74-110 dB for 1-40 years. Almost one third of the workers complained of hearing impairment and the (m)AIADH results showed some hearing difficulties in over half of them. The estimated risk of hearing loss over 25 dB in the frequency range of 3-6 kHz was 41-50% when the standard method of predicting NIHL specified in Standard No. ISO 1999:1990 was used. This risk increased to 50-67% when noise impulsiveness, coexposure to organic solvents, elevated blood pressure and smoking were included in calculations.     

Conceptual framework for evaluation of ecotourism carrying capacity for sustainable development of Karkheh protected area,Iran

The maintenance of natural and virgin ecosystems against an unnecessary influx of humans requires a modern and efficient model such as the carrying capacity model to optimize the management and development of ecotourism in these areas. The model is one of the key tools for conservation and sustainability of these areas. The present research attempts to formulate a framework for the ecotourism carrying capacity model for sustainable development of Karkheh protected area in Iran. The information was collected using a citation method as well as, interviews with experts, and visitors, and director of the region with 24 key indicators being regulated by field surveys and library studies. In this study, the network analysis process model, the Pressure-State-Response conceptual model, and Arc GIS_10.5 software were used to determine the potential for the establishment of ecotourism performance in the scale of 1: 50,000. In this research, 70 questionnaires were completed by experts in the field of environment and ecotourism to determine the relative importance of effective pressures. According to the results, the highest values belonged to physical carrying capacity (13,425,681 persons per day), ecological carrying capacity (2,482,226 persons per day), and social and culture (985,706 people per day), respectively. Based on the regional carrying capacity, the physical, ecological, and social carrying capacity index was calculated as 3356, 621, and 246 (greater than one), respectively. According to the results, the region has a high carrying capacity, which can accept visitors.     

Health risk assessment of potentially toxic elements intake via food crops consumption: Monte Carlo simulation-based probabilistic and heavy metal pollution index

Environmental Science and Pollution Research - The aim of this study is to assess the content of heavy metals and their potential health risk in consumed food crops. To this end, the samples from...     

Reduction of Cr(VI) by peat and coal humic substances

The reduction of Cr(VI) by humic substances from leonardite and peat was investigated by capillary zone electrophoresis at various pHs. Both humic materials reduced Cr(VI) at pH 5.4, but not at basic pH. The capacity of leonardite humic substances to reduce Cr(VI) was lower than that of peat humic substances. Fe(III) accelerated the reduction of Cr(VI) by peat humic substances, but not by leonardite humic substances. Cr(VI) reduction mechanisms are proposed. The coal humic substances seem more suitable for remediation of Cr(VI)-contaminated sites.     

Learning from local knowledge: modeling the pastoral-nomadic range management of the Himba, Namibia.

It is widely accepted that successful grazing management strategies in semiarid ecosystems need to be adapted to the highly temporal and spatially heterogeneous forage production. Nevertheless, a full understanding of the key factors and processes for sustainable adaptive management has yet to be reached. The investigation of existing, successful range management systems by simulation models may help to derive general understanding and basic principles. The semi-nomadic Himba in northern Namibia applied a sophisticated management system until the mid-1990s which combined season-dependent pasture use (resulting in rainy-season pastures and dry-season pastures), preservation of reserves for drought and sanctions for rule breaking. A stochastic ecological simulation model has been developed here which represents the main aspects of this management system. With this model we analyze (1) which components of the traditional Himba strategy are essential for sustainability and (2) what happens to the state of the rangeland system under socioeconomic changes. This study shows that temporally and spatially heterogeneous pasture use yields higher productivity and quality of a pasture area than the pressure of homogeneous permanent grazing. Two aspects are of importance: (1) intra-annual heterogeneous use (resting of the dry-season pastures during the rainy season) and (2) interannual heterogeneous use (spatial extension of grazing in years of drought). This management system leads to an effective build-up and use of a buffer in the system: the reserve biomass (the non-photosynthetic reserve organs of the plants), an indicator for grazing and management history. Analyzing purchase as one form of socioeconomic change, we demonstrate that easier market access to purchase livestock may lead to a decline in vegetation quality. However, cattle production increases as long as rest periods on parts of the pasture during the rainy season are granted. Methodologically, we emphasize that simulation models offer an excellent framework for analyzing and depicting basic principles in sustainable range management derived from local knowledge. They provide the opportunity of testing whether these basic principles are also valid under different ecological and socioeconomic settings.     

Cryptobenthic fishes of the “Ciclopi Islands” marine reserve (central Mediterranean Sea): assemblage composition,structure and relations with habitat features

The fish assemblage of the Ciclopi Islands marine reserve, which is located along the eastern coast of Sicily (Central Mediterranean), was unknown until our study provided insight into the cryptobenthic fish assemblage inhabiting this integral reserve zone. Visual census surveys were periodically conducted along the littoral rocky shores of Lachea, the largest island of the Ciclopi archipelago. The fish assemblage, which comprised 20 species belonging to Blenniidae, Gobiidae, Tripterygiidae, Scorpaenidae and Gobiesocidae, was dominated by Scorpaena maderensis and Trypterigion delaisi. Species richness (S) did not show significant differences between the northern, eastern, southern and western island coasts, whereas both species diversity (H) and evenness (J) were significantly higher on the western coast than on the northern coast. The effect of the island coast on fish density was not significant with regard to the whole assemblage or to single species, except for S. maderensis and T. delaisi. The pattern of variation of assemblage parameters was mainly positively correlated with microhabitat variables, especially substratum composition and type of cover. The best predictors of fish total density were bottom slope, rugosity and substratum composition. Variations in relative species density were specified by a different combination of macro- and microhabitat variables. The density pattern of S. maderensis showed a positive relationship with depth. In T. delaisi, the influence of slope was interrelated to that of exposure to waves. This species preferentially inhabited flat habitat, sheltered from the open sea and covered by small boulders, but also more-exposed rockwalls. The population densities of Tripterygion melanurus and Lipophrys trigloides were negatively affected by depth, thus reflecting their preference for the upper infralittoral. T. melanurus was associated with a more complex habitat (stones and boulders), whereas L. trigloides was mainly censused on a narrow strip of solid rock between the waterline and 1 m depth.Communicated by R. Cattaneo-Vietti, Genova     

Orientation of juvenile barn swallows (<Emphasis Type="Italic">Hirundo rustica</Emphasis>) tested in Emlen funnels during autumn migration

Although hirundines have been used extensively in homing experiments, to date no investigation of their migratory orientation has been carried out, despite the well-known migratory habits of many species of this family. This paper reports on a study of the orientation of the barn swallow (Hirundo rustica), a typical diurnal trans-Saharan migrant. Modified Emlen funnels were used to verify the suitability of this species for cage experiments and investigate the role of visual and magnetic cues during the birds first migratory journey. Juvenile swallows were mist-netted at a roost site in central Italy and then tested in a site 19 km apart. Orientation experiments were performed under four experimental conditions: natural clear sky and simulated overcast, in both local and shifted magnetic fields (magnetic North=geographical West). Under clear sky, the swallows tended to orient phototactically toward the best-lit part of the funnel and failed to respond to the magnetic field shift. Under overcast conditions, they oriented northward and modified their directional choices as expected in response to the shifted magnetic North. On the whole, our data indicate that swallows can use magnetic information for compass orientation. Possible explanations for the northward orientation of birds tested under overcast conditions are discussed.Communicated by W. Wiltschko     

Reproductive isolation between intertidal and subtidal<Emphasis Type="Italic"> Scoloplos armiger</Emphasis> (Polychaeta,Orbiniidae) indicates sibling species in the North Sea

Two distinct modes of development in the common polychaete Scoloplos armiger (O. F. Müller, 1776) occur in the North Sea region: holobenthic development in egg cocoons and pelagic larvae hatching from suspended eggs. In the northern Wadden Sea near the island of Sylt, we observed that egg cocoons are produced intertidally while pelagic larvae originate from the adjacent subtidal zone. A previous genetic comparison between these subtidal and intertidal populations revealed distinct gene pools, suggesting that reproductive differences are not phenotypic but heritable. In this study, crossbreeding experiments show that intertidal and subtidal populations are reproductively isolated. Couples with males and females from different habitats had no offspring. Production of egg cocoons is determined by female origin from the intertidal zone. Pelagic larvae occurred only in couples with subtidal females and subtidal males. Intertidal males have spermatozoa with heads twice as long as those from subtidal males and a significantly shorter flagellum. We suspect that deviating sperm morphology may cause the reproductive breakdown at the fertilization stage. Juveniles hatching from cocoons have shorter anal cirri compared to juveniles that metamorphosed from pelagic larvae. We conclude there to be two sympatric sibling species in S. armiger: 'type I' in intertidal areas, which have egg cocoons, no pelagic larvae, elongated sperm heads, shortened sperm flagella and anal cirri; and a subtidal 'type S', lacking egg cocoons but with pelagic larvae, short sperm heads, long sperm flagella and anal cirri.Communicated by O. Kinne, Oldendorf/Luhe