Chromium fractionation and speciation in natural waters

It is common for leather industries to dump chromium-contaminated effluent into rivers and other bodies of water. Thus, it is crucial to know the impacts caused by this practice to the environment. A study on chromium partitioning and speciation, with determination at trace levels, was carried out in a potentially contaminated creek. Chromium fractionation and speciation was performed using a flow-injection preconcentration system and detection by flame atomic absorption spectrometry. High levels of this element were found in the particulate material (449-9320 mg kg(-1)), which indicates its compatibility with this fraction. The concentration of Cr(iii) in the water samples collected ranged from 5.2-105.2 μg L(-1). Cr(vi) was always below of the DL (0.3 μg L(-1)). Chromium accumulation observed in the sediment (873-1691 mg kg(-1)) may confirm contamination due to the long term release of contaminated effluents in the creek.     

Biological activities of the essential oil from the leaves of Lantana montevidensis (Spreng) Briq. in mice

Environment, Development and Sustainability - This work aimed to analyze the chemical composition and evaluate the anti-inflammatory and antinociceptive properties of the essential oil obtained...     

Dividivi tannins: an ecological product for water-based drilling fluids

Modified tannins are used as deflocculant additives in the formulation of water-based drilling fluids (WBDF) for drilling operations in any scenario. Due to their high heavy metals content, these additives are toxic and hazardous for any environmental scenario. Deflocculant efficiency of unmodified tannins (UDT) extracted from fruit pods of “dividivi” (Caesalpinia coriaria) as an additive for WBDF was assessed. Raw materials for UDT elaboration come from the rural and sustainable exploitation of natural occurring dividivi trees, growing in dry tropical forests in Anzoátegui state (Orinoco Oil Belt, eastern Venezuela). The tannins extract, in the form of dividivi fruit powder, contains 47.0 % of total tannins (hydrolyzable tannins plus condensed tannins), of which 67.4 % corresponds to hydrolyzable tannins. Dividivi tannins in WBDF showed nine (9) times deflocculant efficiency than heavy metals commercial modified tannins. Moreover, commercial modified tannins do not improve their deflocculant efficiency with increased tannin content. Ecotoxicological studies were carried out for WBDF formulations with UDT, using freshwater microalgae Scenedesmus dimorphus as chronic toxicity bioindicator. Toxicity bioassays performed with these microalgae did not show significant effects on its population growth. The EC₅₀ values resulted in over 100,000 mg L^?1, and these formulations were therefore considered non-toxic. Values of LC₅₀ obtained this time with Poecilia reticulata, as acute toxicity bioindicator are around 100,000 mg L^?1, with no significant effects on population mortality. Thus, WBDF formulated with UDT can be considered non-toxic formulations for populations of this freshwater fish. From the social perspective, the use of UDT in WBDF fosters organized communities economical activities based on the maintenance of a sustainable supply chain for processing fruits in a quantity enough to obtain three thousand seven hundred fifty kilograms (3750 Kg). The UDT so obtained was used as deflocculant in four (4) oil wells producing excellent performance and relevant savings compared with commercial modified tannin.     

A new typology for Portuguese beaches: An exploratory study

Beaches are now the most popular tourist destination and increased demand in the past 40 years has led not only to beach congestion but also to a differentiation between urban (resorts, overcrowded and under huge pressure), to natural (less crowded beaches). This diversity needs to be further explored not only to characterize individual beaches in a precise way, but also to understand the distinctive characteristics responsible for options made by beach users. Some attempts have been made to create a universal beach typology but sparse research has been undertaken. The topic is of extreme importance for beach management, as most studies only take into consideration beach usage type and few consider the surrounding environment (landscape). This paper presents an exploratory work for Portuguese beaches which creates a new classification, according to usage and surrounding environment, based on several variables, measured and weighted. The results scale between zero and five and assess how a beach can be classified along an urban (0) to natural (5) spectrum. Variables studied include population density, number of hotels urban density, car park distance to the beach, etc. A pilot study applied to 100 beaches in the Lisbon Metropolitan Area, found that a densely populated region, can also contain beaches with natural characteristics.     

Commodity production as restoration driver in the Brazilian Amazon? Pasture re-agro-forestation with cocoa (<Emphasis Type="Italic">Theobroma cacao</Emphasis>) in southern Pará

The increasing demand for agricultural commodities is a major cause of tropical deforestation. However, pressure is increasing for greater sustainability of commodity value chains. This includes the demand to establish new crop plantations and pasture areas on already deforested land so that new forest clearing for agriculture is minimized. Where tree crops are planted as part of agroforestry systems on deforested land, this amounts to a form of re-agro-forestation which can generate environmental benefits in addition to crop production. Here, we discuss a case where agroforestry systems based on cocoa (Theobroma cacao) are being established on crop and pasture land in the south of Pará state, Brazilian Amazon. The adoption of cocoa by farmers and ranchers of the region is stimulated by the coincidence of (1) favorable prospects for cocoa on the national and international markets including the expectation of a global cocoa supply gap; (2) environmental policies obliging land owners to reforest excess cleared land with native trees, with agroforests based on the native cocoa tree being an economically attractive option; and (3) biophysical conditions (especially soil fertility) favorable for growing cocoa in part of the region. We show that in the state of Pará at least 1.26 million hectares of naturally high-fertility soils in deforested areas outside legally protected and indigenous lands are potentially suitable for cocoa production with low agrochemical inputs, sufficient to make a significant contribution to closing the predicted supply gap. Their actual suitability depends on their state of degradation after years of pasture use and the availability of technologies and finance to convert them into tree crop agroforests. We discuss the significant environmental benefits of pasture re-agro-forestation with cocoa-based systems, including reduced emissions of up to 135 Mg of carbon per hectare compared to the historically common scenario of planting cocoa after forest clearing. We identify important research questions related to the scaling up of this practice and the maximization of its environmental benefits. We conclude that the coincidence of the afore-mentioned factors could drive a re-agro-forestation frontier in this part of the Amazon, with potential for positive outcomes in terms of commodity production while generating social and environmental benefits.     

Oxidative stress status,antioxidant metabolism and polypeptide patterns in Juncus maritimus shoots exhibiting differential mercury burdens in Ria de Aveiro coastal lagoon (Portugal)

This study assessed the oxidative stress status, antioxidant metabolism and polypeptide patterns in salt marsh macrophyte Juncus maritimus shoots exhibiting differential mercury burdens in Ria de Aveiro coastal lagoon at reference and the sites with highest, moderate and the lowest mercury contamination. In order to achieve these goals, shoot-mercury burden and the responses of representative oxidative stress indices, and the components of both non-glutathione- and glutathione-based H₂O₂-metabolizing systems were analyzed and cross-talked with shoot-polypeptide patterns. Compared to the reference site, significant elevations in J. maritimus shoot mercury and the oxidative stress indices such as H₂O₂, lipid peroxidation, electrolyte leakage and reactive carbonyls were maximum at the site with highest followed by moderate and the lowest mercury contamination. Significantly elevated activity of non-glutathione-based H₂O₂-metabolizing enzymes such as ascorbate peroxidase and catalase accompanied the studied damage-endpoint responses, whereas the activity of glutathione-based H₂O₂-scavenging enzymes glutathione peroxidase and glutathione sulfo-transferase was inhibited. Concomitantly, significantly enhanced glutathione reductase activity and the contents of both reduced and oxidized glutathione were perceptible in high mercury-exhibiting shoots. It is inferred that high mercury-accrued elevations in oxidative stress indices were obvious, where non-glutathione-based H₂O₂-decomposing enzyme system was dominant over the glutathione-based H₂O₂-scavenging enzyme system. In particular, the glutathione-based H₂O₂-scavenging system failed to coordinate with elevated glutathione reductase which in turn resulted into increased pool of oxidized glutathione and the ratio of oxidized glutathione-to-reduced glutathione. The substantiation of the studied oxidative stress indices and antioxidant metabolism with approximately 53-kDa polypeptide warrants further studies.     

Diversity and characterization of culturable bacterial endophytes from Zea mays and their potential as plant growth-promoting agents in metal-degraded soils

In this study, we evaluated the phylogenetic diversity of culturable bacterial endophytes of Zea mays plants growing in an agricultural soil contaminated with Zn and Cd. Endophytic bacterial counts were determined in roots and shoots, and isolates were grouped by random amplified polymorphic DNA and identified by 16S ribosomal RNA (rRNA) gene sequencing. Endophytes were further characterized for the production of plant growth-promoting (PGP) substances, such as NH₃, siderophores, indol-3-acetic acid (IAA), hydrogen cyanide and extracellular enzymes, and for the capacity to solubilize phosphate. The endophytes producing higher amounts of IAA were screened for their tolerance to Zn and Cd and used as bioinoculants for maize seedlings grown in the Zn/Cd-contaminated soil. The counts of endophytes varied between plant tissues, being higher in roots (6.48 log₁₀ g^?1 fresh weight) when compared to shoots (5.77 log₁₀ g^?1 fresh weight). Phylogenetic analysis showed that endophytes belong to three major groups: α-Proteobacteria (31 %), γ-Proteobacteria (26 %) and Actinobacteria (26 %). Pseudomonas, Agrobacterium, Variovorax and Curtobacterium were among the most represented genera. Endophytes were well-adapted to high Zn/Cd concentrations (up to 300 mg Cd l^?1 and 1,000 mg Zn l^?1) and showed ability to produce several PGP traits. Strains Ochrobactrum haematophilum ZR 3-5, Acidovorax oryzae ZS 1-7, Frigoribacterium faeni ZS 3-5 and Pantoea allii ZS 3-6 increased root elongation and biomass of maize seedlings grown in soil contaminated with Cd and Zn. The endophytes isolated in this study have potential to be used in bioremediation/phytoremediation strategies.     

Morphological,compositional and ultrastructural changes in the Scrobicularia plana shell in response to environmental mercury – An indelible fingerprint of metal exposure?

The study aimed to assess morphological, structural and compositional alterations in Scrobicularia plana nacre environmentally exposed to mercury in order to seek out the possibility of the assessed alterations as a monitoring tool to handle complexity and interactions of metals in the environment involving a non-invasive methodology. Bivalves were collected from a mercury contaminated site (Laranjo basin – Ria de Aveiro, Portugal) and a reference site in the same aquatic system. The combination of scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS) technique depicted a sheet like morphology of bivalve nacre collected from the reference site. Moreover, EDS plot exhibited the presence of potassium, oxygen, calcium, and carbon elements. Shells collected from the contaminated area depicted lamellar patches like structures with particle like morphology composition. SEM images corresponding to the elemental analysis by EDS plot clearly denoted the presence of mercury. SEM images from the other locations of the contaminated shells depicted large surface area, a broken or ruptured symmetry of organic matrix as well as crack-like gaps. The influence of environmental mercury affecting the surface morphology of S. plana nacre showed dimple like morphology (as proved by transmission electron microscopy, TEM). The possible explanation may be the replacement of calcium elements with other elements or alloys from the nacre composite collected from contaminated region. Therefore, the nacre fingerprint may be useful as innovative knowledge and applicable tool aiming at risk reduction from noxious mercury present in the environment. Overall results suggested the use of shell as an indelible fingerprint of metal exposure.     

Glutathione and its dependent enzymes’ modulatory responses to toxic metals and metalloids in fish—a review

Toxic metals and metalloid are being rapidly added from multiple pathways to aquatic ecosystem and causing severe threats to inhabiting fauna including fish. Being common in all the type of aquatic ecosystems such as freshwater, marine and brackish water fish are the first to get prone to toxic metals and metalloids. In addition to a number of physiological/biochemical alterations, toxic metals and metalloids cause enhanced generation of varied reactive oxygen species (ROS) ultimately leading to a situation called oxidative stress. However, as an important component of antioxidant defence system in fish, the tripeptide glutathione (GSH) directly or indirectly regulates the scavenging of ROS and their reaction products. Additionally, several other GSH-associated enzymes such as GSH reductase (GR, EC 1.6.4.2), GSH peroxidase (EC 1.11.1.9), and GSH sulfotransferase (glutathione-S-transferase (GST), EC 2.5.1.18) cumulatively protect fish against ROS and their reaction products accrued anomalies under toxic metals and metalloids stress conditions. The current review highlights recent research findings on the modulation of GSH, its redox couple (reduced glutathione/oxidised glutathione), and other GSH-related enzymes (GR, glutathione peroxidase, GST) involved in the detoxification of harmful ROS and their reaction products in toxic metals and metalloids-exposed fish.     

Exposure to carbonyl compounds in charcoal production plants in Bahia, Brazil

Studies have investigated the exposure levels of carbonyl compounds (CC) in the indoor and outdoor air of homes, vehicles, workplaces, urban and industrial areas, and rural sites. However, an investigation of these emissions and occupational exposure to CC in charcoal production facilities has not been previously conducted. The objective of this study was to measure the atmospheric concentrations of several CC to assess the exposure of workers of two charcoal plants located north of Salvador, Bahia, Brazil. Stationary and personal samples were collected using Sep-Pak® C18 cartridges that were coated with a 0.2 % acidic solution of 2,4-dinitrophenylhydrazine. The quantification of the resulting 2,4-dinitrophenylhydrazone derivatives was conducted using a high-performance liquid chromatography system with UV detection. In the personal samples, the concentrations of formaldehyde, acetaldehyde, propanone, furfural, and C4 isomers (n-butanal-isobutanal-butanone) ranged from 12 to 139, 38 to 165, 136 to 483, 39 to 114, and 63 to 132 μg?m^?3, respectively. In the stationary samples, the concentrations of these CC ranged from 20 to 160, 111 to 284, 328 to 644, 70 to 163, and 100 to 176 μg?m^?3, respectively. When compared to the occupational exposure limits for 8 h, the concentrations of formaldehyde were often greater than the levels recommended by the American National Institute for Occupational Safety and Health, which indicates a health risk for charcoal workers. These results are the first reported concerning the occupational exposure to CC in charcoal plants.