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.     

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.     

Does (K+Mg+Ca+P) fertilization lead to recovery of tree health in a nitrogen stressed Quercus rubra L. stand?

In The Netherlands atmospheric deposition of nitrogen compounds to forest ecosystems has been very high for some decades and has led to severe nutritional imbalances in soils as well as in trees. At this moment legislation is not fully in effect with respect to lowering emission/deposition fluxes, particularly of nitrogen. The trees suffer mainly from severe magnesium, potassium and calcium and sometimes phosphorus deficiencies. In this study it was investigated whether fertilization with potassium, magnesium, calcium and phosphorus could prevent a Quercus rubra stand from further decline by restoring the nutritional balance, though the detrimental input of nitrogen compounds still continues. Three fertilization treatments were applied: (i) a standard dose of 1250 kg.ha(-1) containing 60 kg P.ha(-1) (as P2O5), 100 kg K.ha(-1) (as K2O), 80 kg Mg.ha(-1) (as MgO) and 340 kg Ca.ha(-1) (as CaCO3); (ii) two times the standard dose; and (iii) three times the standard dose. Soil solution chemistry showed that the highest dose led to the most significant results: an improved nutrient balance and an increased availability of nutrients. After one growing season following fertilization, the trees looked much healthier and crown density had increased. This revitalization lasted for at least four years. For tree health the mid dose seemed appropriate. After the first growing season potassium is the most mobile nutrient, in the soil and also in the trees, but tended to decrease in the fourth year after fertilization. Magnesium and calcium reached normal values in the leaves after four growing seasons. No obvious effects of phosphorus were found.     

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.     

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.     

Two unbalanced segregation products due to a maternal t(7;16)inv(16)

We report a prenatal case of a maternally inherited abnormal chromosome 16, originally interpreted as a pericentric inversion only, but after family studies re-interpreted as a pericentric inversion (16) accompanied by an unbalanced (7;16) translocation. Because of the inversion 16 and an elder son with developmental delay and craniofacial dysmorphic features, in the past karyotyped as 46,XY, the chromosomes 16 of the mother and son were carefully re-examined. Using a whole chromosome 16 paint and sub-telomere probes of 16p and 16q, the karyotype of the mother was shown to be 46,XX,inv(16)(p11.2q23.2).ish t(7;16)(q36;p13.3)inv(16). Subsequently one chromosome 16 of the elder son appeared to be a der(16)t(7;16)(q36;p13.3). This is probably the result of a meiotic crossover between the chromosomes 16 in the mother. The prenatal karyotype was finally interpreted as 46,XY,inv(16)(p11.2q23.2).ish der(16)t(7;16)(q36;p13.3)inv(16). This is the same cytogenetic imbalance as his elder brother: a partial trisomy of chromosome 7 (q36→qter) and a partial monosomy of chromosome 16 (p13.3→pter). Copyright © 2001 John Wiley & Sons, Ltd.