Monitoring of Phenol in Wastewater Bioremediation by HPLC

Bioremediation emphasizes the detoxification and destruction of toxic substances by microorganisms. Wastewater obtained from an industrial concern was solvent extracted with methyl alcohol and dichloromethane and analysed by GC/MS. Besides phenol, a large variety of organic compounds were detected. Under controlled laboratory conditions, the wastewater was innoculated with a mixed culture of microorganisms specially selected for their abilities to degrade phenol. Samples were collected at regular intervals from the stirred tank bioreactor and analysed for phenol by reverse phase HPLC with a C18 column. Results shows that from an initial phenol concentration of 987 ppm, slightly more than 50% was destroyed within 163 hours. The dry weight of the microorganisms and the plate count (CFU/ml) shows a steady increase from 0.5238 gms to 0.5355 gms and from 1.1E+9 to 1.94E+13 respectively over the same period. This suggested that the phenol was consumed by the microorganisms as the sole carbon source.     

Bioaccumulation and depuration of chromium in the selected organs and whole body tissues of freshwater fish Cirrhinus mrigala individually and in binary solutions with nickel

Contamination of aquatic ecosystems with heavy metals has been receiving increased worldwide attention due to their harmful e ects on human health and other organisms in the environment. Most of the studies dealing with toxic e ects of metals deal with single metal species, while the aquatic organisms are typically exposed to mixtures of metals. Hence, in order to provide data supporting the usefulness of freshwater fish as indicators of heavy metal pollution, it has been proposed in the present study to investigate the bioaccumulation and depuration of chromium in the selected organs of freshwater fingerlings Cirrhinus mrigala, individually and in binary solutions with nickel. The results show that the kidney is a target organ for chromium accumulation, which implies that it is also the “critical” organ for toxic symptoms. The results further show that accumulation of nickel in all the tissues of C. mrigala is higher than that of chromium. In addition, the metal accumulations of the binary mixtures of chromium and nickel are substantially higher than those of the individual metals, indicating synergistic interactions between the two metals. Theoretically the simplest explanation for an additive joint action of toxicants in a mixture is that they act in a qualitatively similar way. The observed data suggest that C. mrigala could be suitable monitoring organisms to study the bioavailability of water-bound metals in freshwater habitats.     

Effects of granulated baits on meso and macrofauna in soybean soil system

Studies were done to see the effects of five toxic baits based on metaldehyde and/or carbaryl on the taxonomic composition of soil meso and macrofauna, and determined the density of beneficial organisms in soybean under no tillage. Six treatments were tested and soil monoliths were taken before application and at 45 and 75 days after application (DAA). Before application, 1601 individuals were recorded, belonging 1086 to mesofauna and 515 to macrofauna. In soil mesofauna such as Annelida: Enchytraeidae (44%), Nematoda (33%) and Arthropoda (23%) were found. In the macrofauna Arthropoda 93% and Annelida: Oligochaeta, Megadrilli 7% were observed. No differences were observed among the treatments (p>0.05) in the total mesofauna density, at 45 and 75 DAA. The density of enchytraeids, mites, collembolans and symphylids showed no differences at45 and 75 DAA (p > 0.05). The total macrofauna density showed differences (p < 0.05) at 45 and 75 DAA. The highest density was obtained with 4 kg ha(-1) MataBibos Acay at 45 and 75 DAA. Earthworm and diplopod densities at45 and 75 DAA showed no differences (p>0.05). The diversity of meso and macrofauna was not affected at 45 and 75 DAA. Bait application did not affect either the abundance or the diversity of soil beneficial invertebrates.     

Bioaccumulation of lead and the influence of chelating agents in Catla catla fingerlings

Lead is a widespread element and one of the persistent and cumulative pollutants of the environment. The present study deals with the bioaccumulation of lead and the influence of chelating agents, meso 2,3-dimercaptosuccinic acid (DMSA), D-Penicillamine and CaNa₂EDTA in reducing the concentration of lead on the selected organs of Catla catla fingerlings for both acute and chronic exposures by using ICP-AES. It is inferred from the present findings that there was a correlation between environmental conditions and the heavy metal contents of the fish. The highest concentration of lead is found in kidney tissues and the lowest in muscle tissues. The accumulation pattern of lead in the selected organs of Catla catla is: kidney > liver > gill > brain > muscle. Also, it has been found that the treatment of chelating agents, DMSA, D-Penicillamine and CaNa₂EDTA reduces the concentration of lead significantly for both acute and chronic exposures. The results also show that DMSA is the most effective chelator of lead in reducing the body burden of C. catla fingerlings. The observed data further indicate that C. catla could be suitable for monitoring organisms to study the bioavailability of water-bound metals in freshwater habitats.     

Effect of acute concentration of zinc on the biochemical contents of brain of Labeo rohita: an FT-IR study

Heavy metal discharges to aquatic environment are of great concern due to their toxicity and accumulative behavior. Zinc is an essential trace element required for different physiological functions and plays important role in cellular metabolism. However, it becomes toxic when elevated concentrations are introduced into the environment. The aim of this work is to analyze zinc induced biochemical changes in the brain tissues of Labeo rohita fingerlings using Fourier Transformation Infrared Spectroscopy. Several important features have been observed in the zinc intoxicated brain tissues, namely, altered membrane lipid, altered protein profile and decreased glycogen content, indicating an alteration in the lipid and protein profiles leading to modification in membrane composition. Further, it is observed that the acute exposure to zinc causes some alteration in protein profile with a decrease in α-helix and an increase in random coil structures.     

Genetic diversity in two barnacle species, <Emphasis Type="Italic">Chthamalus stellatus</Emphasis> and <Emphasis Type="Italic">Tesseropora atlantica</Emphasis> (Crustacea,Cirripedia), with different larval dispersal modes in the archipelago of the Azores

ISSRs (Inter Simple Sequence Repeats) were employed to compare the genetic structure of Chthamalus stellatus and Tesseropora atlantica in the Azores. The two barnacles differ as regards life cycle: the former conducting pelagic life for about 22 days, the latter for only 24 h. Thirty individuals of each species were analysed from four locations of three Azorean islands. Five ISSR primers produced, respectively, 117 and 79 polymorphic bands in C. stellatus and T. atlantica. Estimates of among-samples genetic diversity suggested extensive connectivity in the former species and isolation in the latter. AMOVA further supported these results by attributing 2% of genetic variance to the among-islands component of C. stellatus and 30% to T. atlantica. Results are consistent with expectations based on species life history and corroborate the importance of pelagic stages in determining the degree of genetic structuring in benthic marine invertebrates.