Organochlorine insecticide residues in the rain water in Delhi,India

Rain water samples were regularly collected from three sites, namely, Netaji Nagar, Moti Nagar and Town Hall within the Delhi city area from July, 1980 to June, 1982. The pesticide residues were adsorbed on polyurethane foam coated with 0.5 % DC-200 and subsequently extracted and analyzed for DDT, HCH and their metabolites/isomers. The concentration of total DDT ranged from 0.22 to 108 μg L^?1 with a mean value of 12.5 μg L^?1. The samples of rain water contained varying levels of 4,4-DDT, 2,4-DDT, 4,4-DDE, and 4,4-DDD. The 4,4-DDT, 4,4-DDE and 2,4-DDT were the main components of total DDT. The range of HCH residues in rain water was from 0.08 to 43 μg L^?1 with a mean of 5.3 μg L^?1. The residues of HCH consisted mainly of α- and γ-isomers with traces of β and δ-isomers. The α- and γ-isomers accounted for 76 and 24% of total HCH, respectively. The concentrations of DDT and HCH in rain water were generally less than 10 μg L^?1 and exceeded 10 in only 4 and 3 cases, respectively. The residues of these insecticides were generally higher during October to December. Residues of DDT were higher at Moti Nagar which is near a DDT factory. Residues of HCH were maximum at Town Hall, a commercial area of the city.     

DDT residues in the River Jamuna in Delhi,India

Water, Air, &; Soil Pollution - DDT residues in water, bottom sediments and certain non-target organisms from four different sites of the river Jamuna in Delhi were monitored periodically from...     

Liquid chromatographic determination of vitamin D in infant formula

A method is described for the determination of vitamins D2 + D3 in milk- and soy-based infant formula. Vitamins D2 and D3 are extracted from the saponified sample and converted to isotachysterols with acidified butanol. Reverse-phase liquid chromatography (LC) is used to remove interferences, and total vitamin D is quantitated using normal-phase LC. Recoveries of spiked samples averaged 97.6% for milk-based infant formula, and 98.8% for soy-based infant formula. This method quantitates vitamin D2 + D3 in infant formulas containing as low as 40 IU/qt when prepared according to label direction.     

Empirical Explorations of SYNCHEM

During the past several years, a substantial body of experience has accumulated in the use of SYNCHEM, a large-scale program which is able to discover synthesis routes for relatively complex organic structures without on-line guidance on the part of its chemist user. These results indicate that the approach to computer-directed organic synthesis route discovery embodied in the program has been valid and reasonable, and that SYNCHEM is likely to be fruitful from the point of view of its intended users as well as for our research objectives in artificial intelligence. The experiments have revealed a number of insufficiencies in the program as well. Most of these are rectified in SYNCHEM2, a revised version of the program which includes, among other improvements, a more highly developed synthesis search algorithm and the routine consideration of stereochemistry.     

Biochemical and histopathological studies to assess chronic toxicity of triazophos in blood, liver and brain tissue of rats

Triazophos, O,O-diethyl-1-H-1,2,4-triazol-3-yl phosphorothioate, (TZ) is an organophosphorus pesticide which is extensively used in agriculture for controlling insect pests. Except a FAO/WHO report no study has investigated its short-term toxicity with respect to its potential to cause biochemical and histopathological alterations. The present study was designed to identify the effect of TZ at different doses (1.64, 3.2 and 8.2 mg/kg) on the oxidative stress parameters in blood as well as organs involved in xenobiotic metabolism (liver and brain) following chronic exposure for 90 days. Moreover, the study also delineates the effect of TZ on the histo-architecture of these organs. The results indicated a dose dependent induction (p < 0.001) of oxidative stress, as evident by increased malondialdehyde (MDA) level and compromised antioxidant defense including glutathione S transferase (GST) activity, glutathione (GSH) content and ferric reducing ability of plasma (FRAP) in blood, and increased MDA level with concomitantly decreased GSH content in tissues, following chronic exposure to TZ. The ratio of MDA: FRAP in blood was found to be increased following chronic exposure to TZ and may serve as a suitable indicator of severity of oxidative damage. Onset of such biochemical alterations is one of the early adaptive responses to TZ exposure which leads to histopathological alterations in terms of diffuse fatty changes expanding from mid-zonal area to whole lobule in liver. However, increased oxidative stress did not bring any morphological alteration in brain. The present study concludes that induction of oxidative stress, leading to subsequent histopathological alterations in liver, is an important mechanism underlying the TZ induced chronic toxicity.     

Busulphan and thiourea as chemosterilants for the snail lymnaea acuminata

Treatment of the snail Lymnaea acuminata with an alkylating agent (busulphan) or a thiocarbamide (thiourea), for 3 days, significantly reduced the number of eggs and prevented embryonic development. Both the drugs caused a dose dependent reduction in the levels of protein, DNA, RNA and the activity of the alkaline phosphatase of the ovotestis, and a dose-dependent enhancement in the levels of amino-acids and the activity of the acid phosphatase. Discontinuation of the drug treatment for 7 days resulted in a near complete recovery in DNA and RNA levels, while there was no change in the levels of protein, amino-acids and the activities of the acid and alkaline phosphatases.