Suchergebnisse

In the present work, the influence of the competitive effect of inorganic ligands (carbonates, chlorides, fluorides, phosphates, nitrates and sulphates), which can be present in real multi-metal electroplating effluents, on the biosorption of chromium, copper, nickel and zinc ions by yeast cells of Saccharomyces cerevisiae was rationally examined. Additionally, chemical speciation studies allowed optimizing the amount of yeast biomass to be used in the treatment of effluents contaminated with nickel. The applicability of chemical simulation studies was tested using two simulated effluents and validated using one real electroplating effluent, all containing high concentrations of nickel (about 303 μmol l−1). For nickel removal, heat-killed biomass of a brewing flocculent strain of S. cerevisiae was used, in a batch mode. After the implementation of the bioremediation process (12 g dry weight l−1 of yeast cells), the concentration of nickel in the real effluent (34 μmol l−1) reached the quality criteria for industrial effluents discharge, after the second or third batch according to the U.S.-Environmental Protection Agency and Portuguese law, respectively. This corresponded to a removal of nickel of 89%. ; The authors thank to the "Fundacao para a Ciencia e a Tecnologia" (FCT) from Portuguese Government for the financial support of this work with FEDER founds, by the Project POCTI/CTA/47875/2002. Manuela D. Machado is also gratefully acknowledged for a grant scholarship financed under the same project and another grant from FCT ...

Portuguese commercial Elasmobranch landings were analysed for the period 1986 – 2009 and revealed that some species may be in danger of overfishing. Landings totalled 122,515 mt, with an average of 5,105 mt landed yearly, with captured sharks, skates and rays representing 8 orders, 14 families and 44 species. Annual landings for the fishery generally decreased over time, with a corresponding increase in price per kilogram. The most landed group, skates (Raja sp.), accounted for 33% of the landings, or 40,344 mt. They were followed by lesser spotted catsharks (Scyliorhinus sp.), Portuguese dogfish (Centroscymnus coelolepis), leafscale gulper sharks (Centrophorus squamosus), blue sharks (Prionace glauca) and gulper sharks (Centrophorus granulosus) (accounting for 12%, 11%, 10%, 9% and 8% of the landings, respectively). In the absence of CPUE data, comparative trends of landings and price over time were used as an indicator of the status of specific Elasmobranch species. Centrophorus granulosus, smoothounds (Mustelus sp.), torpedo rays (Torpedo sp.), requiem sharks (Carcharhinus sp.) and angel sharks (Squatina sp.) displayed indications of possible over-exploitation, with significantly decreasing landings and increasing prices over time, and merit the focus of future research. The pattern shown by fishing effort over time (i.e. number of fishing vessels over time) displayed a marked decrease, although this was substantially less than the decrease shown by landings of the species mentioned earlier. It is therefore unlikely that such a decrease in landings is justified solely by a decrease in number of fishing vessels. Similarly, the increase in price shown for all species was largely superior to the increase in inflation, which would suggest that the increase in inflation alone would not account for the increase in price. All results and data corroborate the notion that some species are, in fact, over-exploited and in need of immediate management and conservation measurements. These findings were substantiated by min/max auto-correlation factor analysis (MAFA), which shows that the most important trend is that of a decrease in landings of those species where overfishing in indicated. ; Oma – Observatório do Mar dos Açores ; MARE – Centro de Ciências do Mar e do Ambiente ; IMAR – Instituto do Mar ; DOP – Departamento de Oceanografia e Pescas ; Universidade dos Açores ; info:eu-repo/semantics/publishedVersion

As a result of a widespread application in numerous industrial processes, chromium is a contaminant of many environmental systems. Chromium and their compounds are toxic to both invertebrates and vertebrates and, for this reason, there has been a search for suitable and less toxic alternatives. Molybdenum compounds have been studied as alternative to chromium compounds for some industrial applications. The toxicity of chromium is well known but the effects of molybdenum and molybdenum mining on natural populations and communities of freshwater invertebrates have not often been studied. However, chromium, and molybdenum (and their compounds) are included in the same list (List II) of European Union dangerous substances. In this study, the acute and chronic effects of sodium molybdate and sodium dichromate to Daphnia magna Straus were evaluated. Furthermore, in vitro and in vivo effects of these two metals on acetylcholinesterase (AChE) activity of D. magna Straus were investigated. LC50 values determined at 48 h were 0.29 and 2847.5 mg L-1 for chromium (as sodium dichromate) and molybdenum (as sodium molybdate), respectively. No significant in vitro effects of both metals on AChE were found. However, both toxicants inhibited AChE in vivo at concentrations under the respective 48-h LC50 values. Both sodium dichromate and sodium molybdate inhibited the reproduction and growth of D. magna, but the concentrations inducing significant effects were different for the two chemicals. Sodium molybdate had significant lower toxicity to D. magna Straus than sodium dichromate. ; http://www.sciencedirect.com/science/article/B6WDM-45F558P-34/1/d90649021ed4b14cef54a1cad8cba55c

AbstractElectrical and electronic equipment reaching the end of its useful life is currently being disposed of at such an alarmingly high pace that raises environmental concerns. Together with other potentially dangerous compounds, electronic waste contains the rare-earth element gadolinium (Gd), which has already been reported in aquatic systems. Additionally, the vulnerability of aquatic species to this element may also be modified when climate change related factors, like increase in temperature, are taken into consideration. Thus, the present study aimed to evaluate the toxicity of Gd under a scenario of increased temperature in Mytilus galloprovincialis mussels. A multi-biomarker approach and Gd bioaccumulation were assessed in mussels exposed for 28 days to 0 and 10 μg/L of Gd at two temperatures (control – 17 °C; increased – 22 °C). Results confirmed that temperature had a strong influence on the bioaccumulation of Gd. Moreover, mussels exposed to Gd alone reduced their metabolism, possibly to prevent further accumulation, and despite catalase and glutathione S-transferases were activated, cellular damage seen as increased lipid peroxidation was not avoided. Under enhanced temperature, cellular damage in Gd-exposed mussels was even greater, as defense mechanisms were not activated, possibly due to heat stress. In fact, with increased temperature alone, organisms experienced a general metabolic depression, particularly evidenced in defense enzymes, similar to the results obtained under Gd-exposure. Overall, this study underlines the importance of conducting environmental risk assessment taking into consideration anticipated climate change scenarios and exposures to emerging contaminants at relevant environmental concentrations.

ABSTRACT Purpose: To identify the influence of physical and psychosocial stress and health-related factors on the occurrence of work-related accidents, based on the National Health Survey (NHS) conducted in Brazil in 2013, through the execution of a retest in the Brazilian context, according to the model elaborated by Rommel, Varnaccia, Lahmann, Kottner, and Kroll (2016). Originality/value: Brazil has a high rate of workplace accidents. This retest, applied to the Brazilian context based on the German model of Rommel et al. (2016), allows obtaining information concerning the factors that may increase the chances of workplace accidents. Design/methodology/approach: Study with secondary data collected from the National Health Survey (Fiocruz, 2013). The model of Rommel et al. (2016) was used with the set of four blocks of variable factors. Logistic regression explored the physical, psychosocial, and health-related stress factors that may be more likely to occur in the workplace. Findings: 2.8% of the individuals have been involved in some work accident. Model 5 is the most explanatory of occupational accidents and factors such as high school level of education (OR = 2.082), full-time work (OR = 4.814), having three or more jobs (OR = 2.593), exposure to radiation, asthma (OR = 4.880), and alcohol consumption (OR = 4.620), according to each block typified, which most significantly increase the chances for the occurrence of work accidents. Managers and legislators should observe the factors that increase the chances of an accident occurring in order to develop prevention policies or actions.

ABSTRACT Purpose: To identify the influence of physical and psychosocial stress and health-related factors on the occurrence of work-related accidents, based on the National Health Survey (NHS) conducted in Brazil in 2013, through the execution of a retest in the Brazilian context, according to the model elaborated by Rommel, Varnaccia, Lahmann, Kottner, and Kroll (2016). Originality/value: Brazil has a high rate of workplace accidents. This retest, applied to the Brazilian context based on the German model of Rommel et al. (2016), allows obtaining information concerning the factors that may increase the chances of workplace accidents. Design/methodology/approach: Study with secondary data collected from the National Health Survey (Fiocruz, 2013). The model of Rommel et al. (2016) was used with the set of four blocks of variable factors. Logistic regression explored the physical, psychosocial, and health-related stress factors that may be more likely to occur in the workplace. Findings: 2.8% of the individuals have been involved in some work accident. Model 5 is the most explanatory of occupational accidents and factors such as high school level of education (OR = 2.082), full-time work (OR = 4.814), having three or more jobs (OR = 2.593), exposure to radiation, asthma (OR = 4.880), and alcohol consumption (OR = 4.620), according to each block typified, which most significantly increase the chances for the occurrence of work accidents. Managers and legislators should observe the factors that increase the chances of an accident occurring in order to develop prevention policies or actions.