Iron recovery from the coarse fraction of basic oxygen furnace sludge. Part I: optimization of acid leaching conditions

Environmental Science and Pollution Research - In this study, a new reuse process of the coarse fraction of basic oxygen furnace (BOF) sludge based on iron recovery by the ferrous sulfate...     

Diversity of free-living marine nematodes (Enoplida) from Baja California assessed by integrative taxonomy

We used morphological and molecular approaches to evaluate the diversity of free-living marine nematodes (order Enoplida) at four coastal sites in the Gulf of California and three on the Pacific coast of Baja California, Mexico. We identified 22 morphological species belonging to six families, of which Thoracostomopsidae and Oncholaimidae were the most diverse. The genus Mesacanthion (Thoracostomopsidae) was the most widespread and diverse. Five allopatric species, genetically and morphologically differentiated, were found in two localities in the Gulf of California (M. sp1 and M. sp2) and three in the Pacific coast (M. sp3, M. sp4 and M. sp5). Overall, we produced 19 and 20 sequences for the 18S and 28S genes, respectively. Neither gene displayed intraspecific polymorphisms, which allowed us to establish that some morphological variation was likely either ontogenetic or due to phenotypic plasticity. Although 18S and 28S phylogenies were topologically congruent (incongruence length difference test, P > 0.05), divergences between species were much higher in the 28S gene. Moreover, this gene possessed a stronger phylogenetic signal to resolve relationships involving Rhabdodemania and Bathylaimus. On the other hand, the close relationship of Pareurystomina (Enchilidiidae) with oncholaimids warrants further study. The 28S sequences (D2D3 domain) may be better suited for DNA barcoding of marine nematodes than those from the 18S rDNA, particularly for differentiating closely related or cryptic species. Finally, our results underline the relevance of adopting an integrative approach encompassing morphological and molecular analyses to improve the assessment of marine nematode diversity and advance their taxonomy.     

Antioxidant responses in the polychaete Perinereis gualpensis (Nereididae) exposed to the carbon nanomaterial fullerene (C60)

The objective of this study was to analyse biochemical responses induced by the carbon nanomaterial fullerene (C₆₀) in the polychaete Perinereis gualpensis (Nereididae). The activity of glutathione-S-transferase (GST), glutathione reductase (GR) and glutamate cysteine ligase (GCL), as well as total antioxidant capacity, concentration of glutathione (GSH) and malondialdehyde (TBARS), were analysed. Estuarine worms were maintained in sediments collected at an unpolluted site and spiked with fullerene (3 mg C₆₀·g^?1 sediment). A control group was run in parallel. Scanning electron microscope (SEM) images of sediment and fullerene indicated that the size of the carbon nanomaterial should enable it to be ingested by the polychaete. No evidence of oxidative damage (TBARS) was observed in any of the treatments, and the same was true for GSH and GCL measurements (p>0.05). Total antioxidant capacity was higher in the C₆₀ group after 2 and 7 d when compared with the control group (p<0.05), suggesting that fullerene is acting as an antioxidant. The fact that P. gualpensis is an infaunal organism diminishes the chance of fullerene photoexcitation with consequent reactive oxygen species production. Thus, the data indicated an absence of toxic responses mediated by oxidative stress in estuarine worms exposed to C₆₀ mixed in sediments.     

Toxicological effects of N,N,N′,N′-tetramethylethylenediamine on electric eel (Electrophorus electricus) acetylcholinesterase and human serum butyrylcholinesterase

This study examined the adverse effects of N,N,N′,N′-tetramethylethylenediamine (TEMED) on electric eel (Electrophorus electricus) acetylcholinesterase (AChE) and human serum butyrylcholinesterase (BChE). Data show that TEMED inhibited AChE in electric eel as well as human serum BChE. Kinetic studies indicated that the inhibition produced by TEMED in both sources was of mixed type, i.e. K_m increased and V _max decreased in a concentration-dependent manner. K_I (constant of ChE–substrate–TEMED complex into ChE–substrate complex and TEMED) was estimated to be 0.674 mM for electric eel and 0.024 mM for human serum BChE. The γK_m (dissociation constant of ChE–substrate–TEMED complex into ChE–TEMED complex and substrate) was 0.083 and 0.2 mM for electric eel AChE and human serum BChE, respectively. The IC₅₀ for electric eel and for human serum ChE was 1.57 and 0.043 mM, respectively. The present results suggest that TEMED produced adverse effects on electric eel and human serum via inhibition of ChE.     

Quantification of 17 endocrine disruptor compounds and their spatial and seasonal distribution in the Iberian Ave River and its coastline

The Ave River flows through the most urbanized and industrialized Porto district areas. Despite ovotestis was recently reported in male fish from the estuary, no data exist on the water levels of natural and pharmaceutical estrogens (17β-estradiol, estrone, and 17α-ethynylestradiol), xenoestrogenic industrial pollutants (4-octylphenol, 4-nonylphenol and their mono and diethoxylates, and bisphenol A), phytoestrogens (formononetin, biochanin A, daidzein, and genistein), and sitosterol. Absence of analyses applies to the river, estuary, and nearby coastline. Those compounds mimic the action of endogenous estradiol, being well-recognized endocrine disrupters (EDCs). To conclude about suspected influxes of estrogenic EDCs into the river and coastline, water samples were taken at eight sites every two months, during one year (2010), at low tide. Data showed ubiquitous presence of potentially hazardous amounts of estrogens (particularly ethynylestradiol, up to 10 ng L^?1), nonylphenol (up to 250 ng L^?1), and sitosterol (up to 6 μg L^?1), which helps explaining the ovotestis emergence in local fish. Also, because physicochemical parameters used in water quality evaluation, such as pH, dissolved oxygen, nitrates, and nitrites levels, were within legal limits – suggesting good quality – our study supports that assessment of human and environmental risks by targeting surface waters requires integrating EDCs monitoring in routine analyses.     

Traffic culture as symbol exchange - A cross-country comparison of Russia and Norway

The core aim of the study was to gain insight into the cross-country differences in traffic risk perception and driving behaviour and also how culture and cultural differences may influence perceived risk and risk behaviour by comparing a sample of the Russian population with a sample of the Norwegian population. A new measurement instrument aimed at measuring culture as symbol exchange was applied. Self-completion questionnaire surveys were carried out among representative samples of the Norwegian (n = 247) and the Russian (n = 299) population aged 18 years and over. The results showed that culture defined as symbol exchange was weakly associated with risk perception. It is suggested that research carried out to date on the role of culture in risk research may have focused on criterion variables which are not very relevant. However, while traffic safety culture does not seem to be important for risk perception, this study shows that it seems to be relevant for drivers’ risk behaviour and thus it is still relevant and important to focus on traffic culture in risk research despite the fact that culture does not predict perceived risk. As symbol exchange, the newly developed measure of traffic safety culture is capable of predicting drivers’ risk behaviour in traffic and is therefore a valid predictor of traffic safety.     

Population density and conservation status of the teiid lizard <Emphasis Type="Italic">Cnemidophorus littoralis</Emphasis>, an endangered species endemic to the sandy coastal plains (restinga habitats) of Rio de Janeiro state,Brazil

The threatened lizard Cnemidophorus littoralis occurs in only four restinga habitats of Brazilian coast and its current conservation status is “endangered”. Due to its restricted distribution, the effects of habitat degradation are especially harmful to them. To prevent a local or even total extinction, we analyzed changes in population density and in amount of disturbances of three restinga areas during a seven-year gap. This study took place in three restingas of Rio de Janeiro State, Brazil: Maricá, Jurubatiba and Grussaí. We compared C. littoralis current density with the one registered in 2005 by Menezes and Rocha (2013) with 2 ha transections in each restinga. We also made another group of transects to estimate population density along the entire extension of the restingas. Conservation index of each site was based on satellite images and field samplings. Data showed a decreasing trend of Cnemidophorus littoralis population density over the years. Grussaí had the lowest population density and the highest degradation index among the three sites, whereas Jurubatiba had the lowest degree of disturbance, the largest area and the highest lizard population density. Data showed an increase in the amount of disturbance in restingas over the years, which seemed to have a negative effect in C. littoralis population density. Improvement of surveillance and implementation of education programs in the protected areas and its surroundings, and periodic monitoring of C. littoralis populations to follow their density changes, are essential for the maintenance of the species.     

Biogeography of Atlantic and Mediterranean ascidians

Ascidian fauna have been intensively studied in the Atlantic Ocean, adjacent subpolar regions and Mediterranean Sea for the last 20 years. Here, we have described current species distribution patterns and identified nested areas of endemism using parsimony analysis of endemicity (PAE). We also identified diversity hotspots, areas in which species occurred exclusively, and gaps in information about distribution patterns. Finally, we compared ascidian distributions among various proposed biogeographic divisions. The comprehensive literature review provided data on the geographic distribution of 627 species of ascidians. In the West Atlantic, there were three peaks in richness: north Caribbean—96 species, São Paulo and Rio de Janeiro—61 species and the subantarctic region—54 species. In the eastern Atlantic, the greatest richness occurred on Spanish and French coasts—91 species and in Senegal—83 species. In the Mediterranean, the greatest richness was in Spain and France—142 species and Italy—127 species. PAE designated 20 areas of endemism nested within eight larger regions that were more or less in agreement with realms or provinces of previous studies: North Atlantic, Caribbean, southeastern Brazil, Magellanic, Subantarctic, Tropical West Africa, South Africa, and Mediterranean. Distribution patterns of the Ascidiacea, in general, followed previously proposed divisions of regions and provinces in the Atlantic and adjacent polar regions, but not subdivisions of these regions.     

Intensity of land use changes in a sugarcane expansion region,Brazil

In the last decades, Brazil has been consolidated as one of the world’s largest producers of food, with emphasis on soybeans, sugarcane and beef production. With the opening of new markets and the increase in demand, a competitive scenario was developed among farming activities, resulting in changes in land use and cover. Thus, this study aimed to verify the spatial and temporal land use changes, through intensity analysis, in the microregion of Presidente Prudente, São Paulo state, in two time intervals, 2004–2007 and 2007–2015, in addition to determining the relevance of pasture in this context. The identification of land uses occurred through the analysis of the spectrum-temporal pattern of the Normalized Difference Vegetation Index (NDVI) from Moderate-Resolution Imaging Spectroradiometer (MODIS), in such a way that six classes were identified, annual crop, water, sugarcane, forest, pasture and urban area. The categories annual crop and sugarcane had more intense variations of losses and gains in the studied time intervals. The category pasture was the primary supplying source of the area, showing a reduction of approximately 180,000 hectares in the analyzed period, losing area with greater intensity for the categories of annual crop and sugarcane.     

A comparison of organic and inorganic carbon controls over biological denitrification in aquaria

In aquaria and rearing tanks, nitrate accumulation as a result of organic matter degradation is inevitable and has two major negative side effects: direct toxicity to organisms, specially invertebrates, and the introduction of a reducing environment by oxygen consumption. The aim of this study was to compare two alternate methods of removing nitrogen compounds from closed systems, autotrophic columnar denitrification (ACD) and heterotrophic columnar denitrification (HCD) by following end product concentrations as reaction progressed. A pilot plant consisting of two series of 50 dm3 recirculating flow systems (each in triplicate) was used to test both methods. Absence of pH control was also useful in autotrophic denitrification systems in order to follow effects over reaction rates and pathways. Concentrations of NO(3-), NO2- and NH(4+) were followed throughout the experiment, as well as pH, temperature and salinity. Under different flow conditions results show that higher nitrate reduction rates were possible in the autotrophic systems (35.1+/-4.7 microM/day without pH control until reversal of the process and 20.6+/-7.3 microM/day after reestablishment of pH control) in comparison with heterotrophic (9.9+/-1.3 microM/day). However, pH control through calcium bicarbonate addition was found to be crucial in maintaining constant levels of total denitrification in ACD systems, just as it was necessary to closely maintain organic carbon addition to HCD systems.