Behavioural and Physiological Responses of Gammarus pulex Exposed to Cadmium and Arsenate at Three Temperatures: Individual and Combined Effects

This study aimed at investigating both the individual and combined effects of cadmium (Cd) and arsenate (AsV) on the physiology and behaviour of the Crustacean Gammarus pulex at three temperatures (5, 10 and15°C). G. pulex was exposed during 96 h to (i) two [Cd] alone, (ii) two [AsV] alone, and (iii) four combinations of [Cd] and [AsV] to obtain a complete factorial plane. After exposure, survival, [AsV] or [Cd] in body tissues, behavioural (ventilatory and locomotor activities) and physiological responses (iono-regulation of [Na+] and [Cl−] in haemolymph) were examined. The interactive effects (antagonistic, additive or synergistic) of binary mixtures were evaluated for each tested temperature using a predictive model for the theoretically expected interactive effect of chemicals. In single metal exposure, both the internal metal concentration in body tissues and the mortality rate increased along metallic gradient concentration. Cd alone significantly impaired both [Na+] and [Cl−] while AsV alone had a weak impact only on [Cl−]. The behavioural responses of G. pulex declined with increasing metal concentration suggesting a reallocation of energy from behavioural responses to maintenance functions. The interaction between AsV and Cd was considered as ‘additive’ for all the tested binary mixtures and temperatures (except for the lowest combination at 10°C considered as “antagonistic”). In binary mixtures, the decrease in both ventilatory and locomotor activities and the decline in haemolymphatic [Cl−] were amplified when respectively compared to those observed with the same concentrations of AsV or Cd alone. However, the presence of AsV decreased the haemolymphatic [Na+] loss when G. pulex was exposed to the lowest Cd concentration. Finally, the observed physiological and behavioural effects (except ventilation) in G. pulex exposed to AsV and/or Cd were exacerbated under the highest temperature. The discussion encompasses both the toxicity mechanisms of these metals and their interaction with rising temperature

Underground space and urban sustainability: an integrated approach to the city of the future

The use of underground space is not a recent novelty. Its use was primarily defined in regards to survival reasons; protection from natural hazards. Currently, there is a notable increase of underground space applications especially in urban environments. The field of underground space uses is vast in response to various reasons: for commuting and transporting goods to shopping centers, housing and even farming facilities and storage facilities, mining and geothermal energy to nuclear waste disposals. This paper focuses on examining underground space use in today’s urban environments, specifically in urban centers adopting an interdisciplinary and comprehensive approach. This research work introduces the eight global goals for sustainable development based on the United Nations sustainability goals. The methodology used takes into consideration the existing social and economic setting in the cases under investigation, which include both hypothetical models and practices, as well as applied examples of underground spaces in use internationally. Based on two different models of economy, the circular economy and the doughnut economy this paper highlights the principles that should be embedded to achieve resilience and sustainability during the construction and operation of urban infrastructures emphasizing on the spatial contribution of underground developments, on an economic, environmental and furthermost social perspective. By looking into the infrastructural construction of underground spaces, we wish to articulate on their spatial production through the relationships that emerge with the urban environment, and thus examine the balanced evolution of the underground space and its uses. Focusing on determining the underground space’s eco-system will allow for further understanding of its social dimensions and active processes of production, as a spatial node on an intertwined web of spatial networks formulating our urban environments

Interactive toxic effects of heavy metals and humic acids on Vibrio fischeri

The effect of humic acids (HAs) on the toxicity of copper, zinc, and lead was investigated using the photobacterium Vibrio fischeri (Microtox test) as a test organism. The effects of HAs on metal toxicity were evaluated as functions of time and concentration in pure compound solutions. The toxicities of copper and lead were generally comparable, while the toxicity of zinc was lower than those of the other two metals. The toxicity of copper decreased with the addition of HAs, while the toxicity of zinc remained almost constant. On the other hand, the toxicity of lead increased, depending on the concentration of HAs. The interactive effects between copper and zinc and between lead and zinc were synergistic, while the interactive effect between copper and lead on the bioluminescence of V. fischeri was additive. The presence of HAs caused relatively high toxicity reduction in the binary mixtures of zinc and copper or zinc and lead, while the toxicity reduction in the case of the binary mixture of copper and lead was negligible. (c) 2005 Elsevier Inc. All rights reserved

Toxic properties of metals and organotin compounds and their interactions on Daphnia magna and Vibrio fischeri

In the present study toxicity tests were performed in order to determine the toxic properties of four organotin compounds and three heavy metals and to examine the interactive effects of binary metal mixtures on two different test species: the freshwater crustacean Daphnia magna and the marine bacterium Vibrio fischeri. D. magna proved to be more sensitive to metals than V. fischeri. Tributyltin chloride and copper were found to be the most toxic substances on both test organisms. The interactive effects between trimethyltin chloride/copper and trimethyltin/chromium on both test species were investigated and synergistic, additive and antagonistic actions were observed. © 2004 Kluwer Academic Publishers

Toxicity, bioaccumulation, and interactive effects of organotin, cadmium, and chromium on Artemia franciscana

The effects of three organotin compounds-trimethyltin chloride, dimethyltin dichloride, and dibutyltin diacetate-and two heavy metals-cadmium and hexavalent chromium-on Artemia franciscana mortality are investigated in this study. Of all the compounds tested in this work, trimethyltin chloride was, by far, the most toxic. The toxicity order for the five compounds was trimethyltin chloride > potassium dichromate > dimethyltin dichloride > dibutyltin diacetate > cadmium chloride. The big difference in toxicity between dialkyltin and trialkyltin was not accompanied by an equally big difference in bioaccumulation. At a Sn concentration in water of 10 mg/L, the bioconcentration factor was 50 for dimethyltin dichloride and 75 for trimethyltin chloride. At a Sn concentration in water of 100 mg/L, the bioconcentration factor for 6 for dimethyltin dichloride and 9 for trimethyltin chloride. The interactive effect of trimethyltin chloride and cadmium, as well as that of trimethyltin chloride and chromium, was found to be synergistic. Also found to be synergistic was the interactive effect of trimethyltin chloride with cadmium and chromium applied together. (C) 2001 Academic Press