DDT and HCH residues in dairy milk samples collected from different geographical regions of India: a multicentre study.

Under a multicentre study conducted by the Indian Council of Medical Research, 2205 samples of dairy milk were collected from rural and urban areas of 12 states representing different geographical regions of India. These samples were analysed for residues of DDT and different isomers of HCH by gas-liquid chromatography. Analytical quality assurance between various participating laboratories was ensured through analysis of check samples. The residues of DDT and HCH were detected in more than 80% of samples analysed. Concentrations of DDT residues, alpha-HCH, beta-HCH, gamma-HCH and delta-HCH exceeded their maximum residue limits prescribed by the Ministry of Health and Family Welfare of the Indian Government in 37, 21, 42, 28 and 4% of the samples, respectively. Median values of DDT and HCH found in dairy milk in India were more than the corresponding values reported from most other countries. The results showed significant variations in the incidence as well as level of these contaminants in dairy milk from different regions of the country.

Dermal toxicity of hexachlorocyclohexane and pirimiphos-methyl in female rats.

Technical hexachlorocyclohexane (100 mg/kg/d) and pirimiphosmethyl EC 50 (250 mg/kg/d) given individually and in combination to female rats for 7, 15 or 30 d by skin application caused poisoning, pathomorphological changes in vital organs, and significant enzymatic changes in liver and serum. The changes produced by the 2 compounds in combination did not suggest potentiation at the tested dose levels.

Acute and subchronic oral toxicity of technical quinalphos in rats.

The organophosphate insecticide quinalphos is extensively used in agriculture. Information on the mammalian toxicity of quinalphos is limited. The acute po LD50 of technical quinalphos was 19.95 mg/kg in males and 13.78 mg/kg in female rats. Administration of 0.75, 1.50 or 3.0 mg/kg/d technical quinalphos for 90 d po to rats produced poisoning and death. Male rats were more susceptible to quinalphos than female rats in the subchronic toxicity studies based on mortality, enzyme profiles and cholinesterase inhibition.

Interaction of technical hexachlorocyclohexane and oxydemeton methyl 25 EC to female rats after dermal application.

Technical hexachlorocyclohexane (HCH, 100 mg/kg/day) and oxydemeton methyl 25 EC (125 mg/kg/day) to female rats for 7, 15 and 30 days individually and in combination through skin application caused pathomorphological changes in vital organs and significant enzymatic changes in liver and serum. However changes produced by the two compounds in combination were not suggestive of potentiation effect at the tested dose level in female rats.

Fetotoxic response of technical quinalphos in rats.

Technical Quinalphos was administered po to pregnant rats through day 6-20 of gestation at doses of 0.5 or 1.5 mg/kg body weight. Quinalphos produced enzymatic changes in liver and serum of dams associated with mild pathomorphological changes in liver and brain. Fetotoxic effects were not observed at the tested dose levels as determined by total number of implantations, percentage resorption, live fetuses, crown rump length and fetal weight. A few insignificant skeletal deformities were noticed. A significant inhibition of acetylcholinesterase activity in fetal brain and placenta indicated possible transmigration of quinalphos from dams to fetuses.

Long-term dietary study and development of no-observed-effect level (NOEL) of technical HCH to rats.

Daily feeding of technical hexachlorocyclohexane (HCH) (0.5, 5, 25, 250, and 500 mg/kg diet/d) for a period of 360 d to male rats elicited a dose-dependent toxicity, while the dose of technical HCH (0.5 mg/kg diet/d) did not produce signs of intoxication, mortality, organ body weight ratio, enzymatic, and pathomorphological changes. Other doses (5, 25, 250, and 500 mg/kg diet/d) produced significant changes in one or the other parameters studied. Based on this study, it may be suggested that the lowest dose of technical HCH (0.5 mg/kg diet/d) could be considered as the no-observed-effect level in experimental rats.

Response of young rats to repeated oral administration of technical hexachlorocyclohexane.

Male and Female young rats given daily po doses of technical hexachlorocyclohexane (HCH) (5 or 25 mg/kg) for 90 d showed male rats more susceptible to HCH than female. Percent mortality and enzymatic changes were more pronounced in the male rat than in the female. The accumulation of residues in the vital organs of male rat was relatively more than that of the female rat.

Repeated dermal toxicity of technical HCH and methyl parathion (50EC) to female rats (Rattus norvigicus).

Repeated dermal application of hexachlorocyclohexane (HCH; 100 mg/kg/day) or methyl parathion (2 mg/kg/day) individually or in combination for 7, 15 and 30 days produced pathomorphological changes in skin, liver, kidney and brain of female rats along with significant enzymatic alterations in the activity of transaminase, alkaline phosphatase lactic dehydrogenase and acetylcholinesterase. The two insecticides in combination though produced severe toxicity on day 30 than at other periods, the changes were not suggestive of any additive or potentiation effect at the test doses.

Fetotoxicity of hexachlorocyclohexane (HCH) in mice: morphological, biochemical and residue evaluations.

Administration of single po doses of technical hexachlorocyclohexane (HCH) (5, 25, 50, 100 or 200 mg/kg) to mice on day 9 of gestation caused dose-related toxic effects in the fetuses. HCH-treated dams had consistent decreases. The percent resorption and the number of live fetuses/dam indicated that high concentrations of HCH trigger fetotoxic effects. Enzymatic changes in the livers of control and HCH-treated groups showed significant alterations. Accumulation of HCH was in the fatty tissue, brain, liver and blood.

Dermal toxicity to rats of isoproturon technical and formulation.

Information on the toxicity of urea-based herbicides is meagre and no data are available on the subacute dermal toxicity of isoproturon and its formulation. Repeated applications of isoproturon technical (IPT) and its wettable powder formulation (IPF) to the skin of male and female rats for 21 days caused mild to moderate toxic effects. IPT was more toxic to male rats as evidenced by animal mortality and enzymatic and hematological changes. The toxicity of IPF was less to both sexes. No dose response relationship could be established since the enzymatic and hematological changes produced by 3 different dose levels were equal.

Toxicity of pure alkaloid of Tylophora asthamatica in male rat.

Administration of pure alkaloid of T. asthamatica, suspended in peanut oil and given in single doses (12-100 mg/kg) by gavage, to male rats caused inactivity, respiratory distress, salivation, nasal discharge and diarrhoea. The oral LD50 value of the alkaloid was 35.32 mg/kg. In short term toxicity study daily doses of the alkaloid (1.25, 2.5, 5 and 10 mg/kg) were given to male rats for 15 days. Smaller doses of the alkaloid (1.25 and 2.5 mg/kg/day) produced no signs of poisoning or death in animals; while 5 mg/kg/day produced signs of poisoning and death of two animals, 10 mg/kg/day caused death of all the animals within 7 days. Activities of glutamic oxaloacetic transaminase, glutamic pyruvic transaminase and alkaline phosphatase were significant and associated with morphological changes in liver. The alkaloid also caused marked changes in the morphology of seminiferous tubules and spermatogenic activity of experimental animals. Since the alkaloid is effective in microgram quantities, the non toxic effects observed after daily doses of 1.25 mg/kg in male rats assume great therapeutic significance.

90-day oral toxicity of ziram: a thyrostatic and hepatotoxic study.

Ziram, a dithiocarbamate fungicide, is extensively used in crop protection. Daily oral doses of ziram (5 and 25 mg kg(-1) day(-1)) for 30, 60 and 90 days produced significant mortality in male rats. The fungicide also caused a significant increase in the thyroid:body weight ratio, histological changes, and a reduced activity of thyroid (125)I uptake and protein bound (125)I. However, the animals did not show any change in the clinical enzyme profile of the liver, serum and brain. It is believed that ETU, the degradation product of ziram and a known antithyroid compound, is the causative agent for the high mortality, as well as for the pronounced thyrostatic and hepatotoxic effects found in the experimental animals.

Acute toxicity of hexachlorocyclohexane (HCH) in mice, rats, rabbits, pigeons and freshwater fish.

Technical Hexachlorocyclohexane (HCH) is a mixture of several stereo isomers, whose percent content has shown wide variation in different samples. In spite of its importance and extensive use over the last 3 decades, basic information on acute toxicity of HCH in various species of animals seems to be either lacking or very fragmentary. The present report with information on acute toxicity of technical HCH in mice, rats, rabbits, pigeon and freshwater fish therefore has significance. The study examines the role of modulating factors, such as chemical composition of technical HCH with different isomers, the sex of animals, route of exposure and nature of the vehicle or solvent, in the overall characterization of HCH-induced toxicity.

Dermal toxicity of hexachlorocyclohexane (HCH) in rabbit.

Application of HCH (25 mg/kg) on dorsal, ventral and thigh regions of the skin of male rabbits resulted in poisoning and mortality of animals. Morphological changes in skin, liver, kidney, testes and cerebellum together with highly significant alterations in serum and liver enzymatic activity and residue in blood suggested that absorption of HCH and its toxicity could be severe when the pesticide comes in contact with the skin of thigh region of body.

Interaction of hexachlorocyclohexane (HCH) and chlorpropham (CIPC) in male rats.

Hexachlorocyclohexane (60.0 mg/kg/d) and chlorpropham (50.0 mg/kg/d) given to male rats daily orally for 30 d caused subtle biochemical lesions. The significant rise in the activity of alkaline phosphatase in liver and serum and of GOT and GPT in liver with substantial weight increase of liver has been suggestive of the initiation of biochemical lesions and adaptation of the organism. Very severe hepatocellular damage is forecasted if the pesticides are given for a prolonged period and in higher concentrations to animals.

Effect of repeated dermal application of endosulfan to rats.

Dermal application of endosulfan to male (18.75, 37.50 and 62.50 mg/kg/day) and female (9.83, 19.66 and 32.0 mg/kg/d) rats for 30 days produced hyperexcitability, tremor, dyspnea and salivation. There were no deaths. The signs of toxicity subsided after a week. Endosulfan produced no significant changes in the organ:body weight ratio. No significant changes were seen in the histological and hematological indices. However, a significant decrease in liver GOT and GPT and serum GPT activities and a significant rise in serum alkaline phosphatase and total protein were recorded in the endosulfan-treated animals. There were no changes in LDH. Residue analysis revealed higher levels of total endosulfan in fatty tissues of rats receiving the highest dose of endosulfan.