Effects of 2,4,6-Trichlorophenol on Clarias batrachus: a biomarkers approach

2,4,6-Trichlorophenol (2,4,6-TCP) is a common waste among the resulting chlorophenols generated in the production of common products classified as an extremely toxic, mutagenic, carcinogenic and highly persistent xenobiotic in the environment. To evaluate the impact of 2,4,6-TCP in aquatic systems, the catfish species Clarias batrachus has been selected to test its toxicity due to its high market value and consumption in India. Here is presented the impact of this compound on different physiological parameters of fish: haematological parameters (haemoglobin, total erythrocyte count, total leucocyte count and mean corpuscular haemoglobin), biochemical parameters (total serum protein and total serum glucose), growth and reproductive parameters (condition factor, hepatosomatic index, maturity index, specific growth rate, growth hormone, 17β-estradiol and testosterone), exposed to two concentrations of 2,4,6-TCP (0.5 mg/L and 1 mg/L — 1/10th and 1/20th of the LC50) for a period of 15, 30 and 45 days. The results showed that C. batrachus even when exposed to the lower concentration (0.5 mg/L) for the shortest time (15 days) negatively impacted the organism in all the assessed parameters. This was highlighted by the Integrated Biomarker Response index (IBR), showing worse scores for the treatments (up to 20 × worse than the control). This work highlights the importance of continued research on the impact of 2,4,6-TCP, on an important commercial, supported by the high environmental persistence of this compound that can reach the same range of tested concentrations

Evaluation of the joint effect of glyphosate and dimethoate using a small-scale terrestrial ecosystem

In the present work a small-scale terrestrial ecosystem (STEM) containing a soil collected from an agricultural field in Central Portugal was used to evaluate the effects of the combination of the herbicide glyphosate and the insecticide dimethoate. Earthworms (Eisenia andrei), isopods (Porcellionides pruinosus), turnip seeds (Brassica rapa), and bait-lamina strips were placed in the STEM. The results showed that the application of the recommended field dose of both pesticides did not cause any effect on the weight variation of earthworms and growth of the plants. The application of the herbicide, even at 5 and 10 times the field dose, increased feeding activity in soil (bait-lamina test), although the application of dimethoate led to a decrease in feeding activity in all concentrations tested. The binary mixtures performed showed that according to the Independent Action model, synergism (higher effect than expected from the single exposures) was observed in both the shoot length and fresh weight of B. rapa at 5 times the field dose, but antagonism was observed at 10 times the field dose. Regarding the germination success, synergism was observed at the field dose, but antagonism was detected at 5 times and 10 times the field dose. There was a decrease on the earthworm's weight in all concentrations tested, although no statistical differences were observed in any of the treatments made. Regarding depth distribution of E. andrei, worms were found in the upper layer more than it was predicted for all concentrations. In the mixtures with the field and 5 times the field dose there was a decrease in the feeding activity (bait-lamina consumption) by the soil fauna. From the four biomarkers assessed on the isopods (Catalase, Acetylcholinesterase, Glutathione-S-transferase, and Lipid peroxidation), only a significant decrease in the Acetylcholinesterase activity upon dimethoate and the binary mixtures exposures performed with the field dose was observed and on Lipid peroxidation at the field doses of single and binary exposures. (C) 2011 Elsevier Inc. All rights reserved

Computational and experimental study of time-averaged characteristics of positive and negative DC corona discharges in point-plane gaps in atmospheric air

The use of stationary solvers instead of approximate solution methods or time-dependent solvers, which are standard tools in gas discharge modeling, allows one to develop a very fast and robust numerical model for studying the time-averaged characteristics of dc corona discharges. Such an approach is applied to dc corona discharges in point-plane gaps in ambi ent air. A wide range of currents of both voltage polarities and various gap lengths are investigated, and the simulation results are validated by comparing the computed current–voltage characteristics and spatial distributions of the radiation intensity with experimental results. Specific features of the numerical and experimental results at both polarities are discussed.info:eu-repo/semantics/publishedVersio

Background-free four-wave mixing microscopy of small gold nanoparticles inside a multi-cellular organ

The ability to detect small metallic nanoparticles by optical microscopy inside environmentally relevant species may have a wide impact for ecotoxicology studies. Here, we demonstrate four-wave mixing microscopy on individual small gold nanoparticles inside the hepatopancreas of Oniscus Asellus, a terrestrial isopod, which ingests metals found in the soil. After the exposure to food containing 10 nm radius gold nanoparticles, hepatopancreas tubules were collected, and nanoparticles were imaged by four-wave mixing microscopy with high contrast, locating them with sub-cellular resolution in the volume, despite the significant light scattering from these multi-cellular organs. Notably, the ultrafast dynamics of the four-wave-mixing non-linearity of gold nanoparticles resonantly excited and probed at their localized surface plasmon allows them to be distinguished from other metal deposits in the hepatopancreas, which manifest as a long-lived photothermal contrast. Our findings bring unexpected insight into the location of gold nanoparticles in relation to the cell types forming the hepatopancreas. Considering its simplicity, volumetric imaging capabilities, specificity, and compatibility with living cell studies, four-wave mixing microscopy holds great potential to investigate the fate of metal nanoparticles inside biological systems

Thermochemical conversion processes as a path for sustainability of the tire industry: carbon black recovery potential in a circular economy approach

The common use of tires is responsible for the production of large quantities of waste worldwide, which are landfilled or energetically recovered, with higher economical cost and known environmentally harmful consequences. This type of problem must be studied, and all efforts must be conducted to eliminate, or at least mitigate, such high costs. The use of thermochemical conversion processes, such as pyrolysis, can allow the recycling and the reuse of raw materials for the tire industry, namely, in the production of carbon black, usually produced using the controlled combustion of fossil fuels. This article reports the production of torrefied and carbonized waste tire samples using a laboratorial procedure, and their subsequent laboratory characterization, specifically the elemental and proximate analysis. This preliminary approach found that carbon concentration in the produced rubber char reached values higher than 75%, indicating the possibility of its reuse in the production of carbon black to in turn be used in the production of new tires or other industrial rubber materials. The possibility of using this rubber char for other uses, such as energy recovery, is still depending on further studies, namely, the evaluation of the amount of sulfur present in the final product

Background-free 3D four-wave mixing microscopy of single gold nanoparticles inside biological systems

Individual small gold nanoparticles are imaged in 3D background-free with high contrast by four-wave-mixing interferometry inside living mouse oocytes and multi-cellular organs, despite the strong linear scattering background in these large samples

Mercury accumulation from food decreases collembolans' growth

In the terrestrial environment, mercury (Hg) contamination can be originated from different inorganic and metal-organic sources, redistributed and transformed in soils. In the present study, the effects of contaminated food with environmentally relevant concentrations of Hg were evaluated in the soil-dwelling invertebrate Folsomia candida. Changes in growth rate and Hg bioaccumulation levels were observed at different concentrations of Hg in food, which can be complementary for data already available for reproduction and survival from standardized protocols. Collembolan growth was recorded every two days, and their growth rate along with a Von Bertalanffy's growth curve were derived showing that growth was dependent on Hg food concentration. Also, the final length of animals reflected the Hg concentration in food, with differences in all treatments comparing to non-exposed organisms. Toxicokinetic patterns from different Hg concentrations in food were not significantly different during the uptake phase, but differences were found in the depuration phase. Combining the two approaches, collembolans seem to invest their energy for depuration processes, neglecting other vital processes, such as growth. Also, contaminated food avoidance possibly occurred, thus decreasing their feeding and contaminant intake. Therefore, growth tests in collembolans can act as complementary tools to bioaccumulation and reproductive assays, towards a mechanistic understanding of how organisms use their energy upon contamination. Changes in growth rate, even at low and environmentally relevant concentrations, could be a warning signal when occurring in species with key roles in ecosystems. Also, this study highlights the importance of these complementary tests for a better and complete approach to risk assessment studies

Metabolic consequences of the water we drink: a study based on field evidence and animal model experimentation

The effect of the chronic consumption of water contaminated with residual concentrations of DDT’s metabolites (DDD—dichlorodiphenyldichloroethane and DDE—dichlorodiphenyldichloroethylene) found in the environment were evaluated on the biometric, hematological and antioxidant system parameters of the hepatic, muscular, renal and nervous tissues of Wistar rats. The results showed that the studied concentrations (0.002 mg.L−1 of DDD plus 0.005 mg.L−1 of DDE) could not cause significant changes in the hematological parameters. However, the tissues showed significant alteration in the activity of the antioxidant system represented by the increase in the activity of the enzymes gluthathione S-transferases in the liver, superoxide dismutase in the kidney, gluthathione peroxidase in the brain, and several changes in enzymatic activity in muscle (SOD, GPx and LPO). The enzymes alanine aminotransaminase (ALT) and aspartate aminotransaminase (AST) were also evaluated for the amino acids’ metabolism in the liver, with ALT showing a significant increase in the exposed animals. In the integrative analysis of biomarkers (Permanova and PCOA), the studied concentrations showed possible metabolic changes and damage to cellular structures evidenced by increased oxidative stress and body weight gain among the treated animals. This study highlights the need for further studies on the impact of banned pesticides still present in soils that may induce adverse effects in organisms that may prevail in future generations and the environment

Insights on the mechanism of formation of protein microspheres in a biphasic system

Microspheres of bovine serum albumin (BSA) and silk fibroin are produced by applying ultrasound in a biphasic system consisting of an aqueous protein solution and an organic solvent. The protein microspheres are dispersed in an aqueous media where the protein remains at the interface covering the organic solvent. This only occurs when high shear forces are applied that induce changes to force the protein to the interface. Fourier transform infrared results indicate a large increase in the content of the β-sheet during the formation of silk fibroin microspheres. Molecular dynamics simulations show a clear adaption on the 3D structure of BSA when stabilized at the interface, without major changes in secondary structure. Further studies demonstrate that high water content, oil solvents, and larger peptides with separated and clear hydrophobic and hydrophilic areas lead to more stable and smaller spheres. This is the first time that these results are presented. We also present herein the rationale to produce tailored protein microspheres with a controlled size, controlled charge, and increased stability.This work was supported by Lidwine Project-Multifunctional medical textiles for wound (e.g., Decubitus) prevention and improved wound healing NMP2-CT-2006-026741. H.F. thanks POPH/FSE for cofinancing and FCT for Fellowship SFRH/BPD/38939/2007. We acknowledge Silvia Cappellozza from "Sezione Specializzata per la Bachicoltura" for the supply of silk cocoons