Organochlorine pesticides and polychlorinated biphenyls in sediments and fish from freshwater cultured fish ponds in different agricultural contexts in north-eastern France

Organochlorine pesticides (HCB, HCH with α-, β-, and γ isomers, heptachlor, cis-heptachlor epoxyde, trans-heptachlor epoxyde, endosulfan with α- and β isomers, sulfate endosulfan, o,p'-DDT, p,p'-DDT, o,p'-DDE, p,p'-DDE, o,p'-DDD, p,p'-DDD, chlorothalonil, alachlor, aldrin, dieldrin, methoxychlor, oxychlordane, chlordane with α- and γ isomers, p,p'-dicofol and o,p'-dicofol) and indicators PCBs (IUPAC nos. 28, 52, 101, 118, 138, 153, and 180) were studied both in sediments and muscles of farmed fish species (Cyprinus carpio and Perca fluviatilis). Samples were collected from fish ponds located in the hydrographic basin of the Moselle River (Lorraine Region, France). OCPs and PCBs were present at low concentrations both in sediments and fish muscles. Concerning sediments, ∑DDTs revealed concentrations ranging from 0.2 to 2.30 ng g(-1) dw and ∑PCBs ranged from 0.3 to 3.5 ng g(-1) dw. Concerning fish muscles, the highest concentrations in OCPs were those of p,p'-DDE, with average concentrations of 0.57±0.44 ng g(-1) ww for carp and 0.58±0.29 ng g(-1) ww for perch. The contamination profiles proved to be different depending on the fish species. Indeed, HCH-isomers, HCB, and dieldrin were detected only for the carp and always at low concentrations. For example, the highest concentration of HCHs was observed for β-HCH with a mean value of 0.64±0.15 ng g(-1) ww for carp. As for PCBs, the levels of ∑PCBs ranged from 0.3 to 6.4 ng g(-1) ww in carp muscles and from 0.90 to 5.60 ng g(-1) ww in perch muscles.

Monograph: reassessment of human cancer risk of aldrin/dieldrin

In 1987, the US Environmental Protection Agency (EPA) classified aldrin and dieldrin as category B2 carcinogens, i.e. probable human carcinogens, based largely on the increase in liver tumors in mice fed either organochlorine insecticide. At that date, the relevant epidemiology was deemed inadequate to influence the cancer risk assessment. More time has now elapsed since early exposures of manufacturing workers to aldrin/dieldrin; therefore, updated epidemiological data possess more power to detect exposure-related differences in cancer risk and mortality. Also, recent experimental studies provide a plausible mode of action to explain the mouse specificity of dieldrin-induced hepatocarcinogenesis and call into question the relevance of this activity to human cancer risk. This monograph places this new information within the historic and current perspectives of human cancer risk assessment, including EPA's 1996 Proposed Guidelines for Carcinogen Risk Assessment. Updated epidemiological studies of manufacturing workers in which lifetime exposures to aldrin/dieldrin have been quantified do not indicate increased mortality or cancer risk. In fact, at the middle range of exposures, there is evidence of a decrease in both mortality from all causes and cancer. Recent experimental studies indicate that dieldrin-induced hepatocarcinogenesis in mice occurs through a nongenotoxic mode of action, in which the slow oxidative metabolism of dieldrin is accompanied by an increased production of reactive oxygen species, depletion of hepatic antioxidant defenses (particularly alpha-tocopherol), and peroxidation of liver lipids. Dieldrin-induced oxidative stress or its sequelae apparently result in modulation of gene expression that favors expansion of initiated mouse, but not rat, liver cells; thus, dieldrin acts as a nongenotoxic promoter/accelerator of background liver tumorigenesis in the mouse. Within the framework of EPA's Proposed Guidelines for Carcinogen Risk Assessment, it is proposed that the most appropriate cancer risk descriptor for aldrin/dieldrin, relating to the mouse liver tumor response, is 'not likely a human carcinogen', a descriptor consistent with the example of phenobarbital cited by EPA.

Protective role of ascorbic acid in fishes exposed to organochlorine pollution

Protective role of ascorbic acid on the toxic effect of aldrin pollution in an air-breathing fish Channa punctatus Bloch is reported. Fishes fed with aldrin mixed diet at 0.25% showed 25% mortality in 30 days. Mortality is preceded by certain changes in peripheral blood such as polycythemia and leucocytosis with increased thrombocyte but decreased neutrophil population. However, a massive dose of ascorbic acid (500 mg/100 g diet) was found to considerably neutralize the toxic effect as evidenced by 10-fold decrease in mortality and significantly lowered haematological response. The significance of these studies in the light of physiological role of ascorbic acid as a micronutrient for protection against pollution stress is discussed.

Discriminating the molecular basis of hepatotoxicity using the large-scale characteristic molecular signatures of toxicants by expression profiling analysis

Predicting the potential human health risk posed by chemical stressors has long been a major challenge for toxicologists, and the use of microarrays to measure responses to toxicologically relevant genes, and to identify selective, sensitive biomarkers of toxicity is a major application of predictive and discovery toxicology. To investigate this possibility, we investigated whether carcinogens (at doses known to induce liver tumors in chronic exposure bioassays) deregulate characteristic sets of genes in mice. Male C3H/He mice were dosed with two hepatocarcinogens (vinyl chloride (VC, 50-25 mg/kg), aldrin (AD, 0.8-0.4 mg/kg)), or two non-hepatocarcinogens (copper sulfate (CS, 150-60 mg/kg), 2,4,5-trichlorophenoxyacetic acid (2,4,5-T, 150-60 mg/kg)). Large-scale molecular changes elicited by these four hepatotoxicants in liver tissues were analyzed using DNA microarray. Three days after administration, no significant phenotypic changes were induced by these four different hepatotoxicants in terms of histological examination or blood biochemical assay. However, unsupervised hierarchical analysis of gene expressional changes induced by hepatotoxicants resulted in two major gene subclusters on dendrogram, i.e., a carcinogen (VN, AD) and non-carcinogen group (CS, 2,4,5-T), and also revealed that distinct molecular signatures exist. These signatures were founded on well-defined functional gene categories and may differentiate genotoxic and non-genotoxic carcinogens. Furthermore, Venn diagram analysis allowed us to identify carcinogen and non-carcinogen-associated molecular signatures. Using statistical methods, we analyzed outlier genes for four different classes (genotoxic-, non-genotoxic-carcinogen, genotoxic-, non-genotoxic non-carcinogen) in terms of their potential to predict different modes-of-action. In conclusion, the identification of large-scale molecular changes in different hepatocarcinogen exposure models revealed that different types of hepatotoxicants are associated with different epigenetic changes and molecular pathways and that these large-scale characteristic molecular changes could be used as predictable toxicity markers.

Clastogenicity evaluation of seven chemicals commonly found at hazardous industrial waste sites

7 chemicals commonly found at the industrial waste sites were tested with the Tradescantia-Micronucleus (Trad-MCN) assay to evaluate their clastogenic potential. Chemicals selected from the US EPA Superfund Priority 1 list were: aldrin, arsenic trioxide, 1,2-benz[a, h]anthracene, dieldrin, heptachlor, lead tetraacetate and tetrachloroethylene. Results of repeated tests for clastogenicity yielded the minimum effective dose (MED) for clastogenicity of 0.44 ppm for lead tetraacetate, 1.88 ppm for heptaclor, 3.81 ppm for dieldrin and arsenic trioxide and 1,2-benz[a, h]anthracene yielded positive responses at the MED of 3.96 ppm and 12.50 ppm respectively. Aldrin and tetrachloroethylene were considered to be immiscible with water, and the tests yielded negative responses. Tetrachloroethylene in gaseous state was also used to treat the flower buds. Results of tetrachloroethylene vapor phase treatment yielded a positive response at the MED of 30 ppm/min after a 2-h exposure. 5 chemicals determined to be clastogens by this test were ranked according to their MED in the descending order of potency as follows: lead tetraacetate, heptachlor, dieldrin, arsenic trioxide and 1,2-benz[a, h]anthracene. Results of this study indicate that the Trad-MCN bioassay could be effectively utilized for assessing the potential clastogenicity of the chemicals commonly found at the industrial hazardous waste sites.

Histopathology of Carcinomas of the Liver in Mice Ingesting Dieldrin or Aldrin

C3HeB/Fe male and female mice, ingesting 10 ppm of the pesticides dieldrin or aldrin in the diet, developed highly significant incidences of carcinomas of the liver. The carcinomas varied from well differentiated to poorly differentiated and undifferentiated and were capable of metastasis.

Inhibition of gap junctional intercellular communication in human teratocarcinoma cells by organochlorine pesticides

Inhibition of intercellular communication, as measured by metabolic cooperation between 6-thioguanine-sensitive and 6-thioguanine-resistant Chinese hamster V79 cells, has been previously shown to be correlated with a large variety of known tumor promoters, including some of the organochlorine pesticides. Since further evidence concerning the effects of those known or suspected animal tumor promoters on human cells is needed, three organochlorine pesticides, dieldrin, aldrin, and 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT), were tested for their ability to inhibit metabolic cooperation between 6-thioguanine-sensitive (6TGs, HTP3-4) and 6-thioguanine-resistant (6TGr, HTXTG-1) human teratocarcinoma cells. Similar to the effect of the known mouse skin tumor promoter 12-tetradecanoyl phorbol-13-acetate (TPA), all three pesticides inhibited gap junctional intercellular communication within a noncytotoxic dose range. The dose-response curves of these chemicals were similar to those of other known tumor promoters on Chinese hamster V79 cells. In addition, the transfer of [3H]uridine between teratocarcinoma cells in contact was reduced after pesticide treatment.

Effects of cyclodiene compounds on calcium pump activity in rat brain and heart

The in vitro and in vivo effects of aldrin, dieldrin, and endrin on calmodulin regulated Ca2+-pump activity in rat brain synaptosomes and heart sarcoplasmic reticulum were investigated. All the 3 cyclodiene compounds inhibited both brain synaptosomal and heart sarcoplasmic reticulum Ca2+-pump activity in vitro in a concentration dependent manner. Calmodulin depleted Ca2+-pump activity was insensitive to the action of toxic compounds. Oral administration of pesticides (0.5-10 mg/kg) to rats similarly decreased the Ca2+-pump activity, in addition to decreasing the levels of calmodulin of both brain and heart thus indicating disruption in membrane Ca2+ transport mechanisms. Exogenous addition of calmodulin (1-20 micrograms) could effectively reverse the pesticide induced inhibition. Ca2+-pump activity is more sensitive to the 3 cyclodiene compounds in brain than in heart. The results of the present study indicate that the cyclodiene compounds may produce neurotoxic effects by altering calmodulin regulated calcium dependent events in neurons.

Enantioselective behavior of alpha-HCH in mouse and quail tissues

alpha-HCH (hexachlorocyclohexane) is chiral and can still be detected in almost all environmental media. In this study, the enantioselective behavior of alpha-HCH in mice (CD1) and quail (Coturnix japonica) was investigated and compared after a single dose of exposure. The primary nerve cell culture was conducted to evaluate the enantioselective metabolic capacity of nerve cells of mouse and quail for alpha-HCH. In various tissues of the mice and quail, the alpha-HCH concentrations showed a typical pattern of first-order dynamics after exposure. The enantiomeric fractions (EFs) in nonbrain tissues of mice decreased substantially, indicating continuous depletion of (+)-alpha-HCH in mice. Tissue-specific EF trends in quail and enantioselective degradation of (-)-alpha-HCH in quail liver were observed. These observations indicated that the dynamic changes of EFs in mice and quail were independent of concentration changes in the same tissues. In brain tissues, the enantioenrichment of (+)-enantiomer was totally independent of their concentrations in blood. The in vitro metabolism of alpha-HCH in the primary nerve cells were negligible, and the slight EF changes in primary nerve cells demonstrated that metabolism, uptake, and excretion in the brain cells would not lead to the observed dramatic enantioenrichment of (+)-alpha-HCH in the brain tissues of the two animals. The enantioselective transport across the blood-brain barrier was the primary cause for the enantioenrichment of (+)-alpha-HCH in the brain tissues.

Further characterization of the in vitro assay for inhibitors of metabolic cooperation in the Chinese hamster V79 cell line

12-O-Tetradecanoylphorbol-13-acetate (TPA) has been previously shown to inhibit metabolic cooperation in Chinese hamster V79 cells. An in vitro assay, based on this phenomenon, has been developed to study tumor promoters. Several parameters concerning the metabolic cooperation assay using V79 Chinese hamster cells were further investigated in this report. Pretreatment of the cells with TPA in situ for different periods of time did not result in any detectable change in the inhibition of metabolic cooperation. If cells were replated after TPA treatment, a different result was obtained. There was an apparent decrease in the ability of TPA to inhibit metabolic cooperation when TPA was added back to the TPA-pretreated cultures. However, when TPA was omitted from the TPA pretreated cultures after replating, the inhibition of metabolic cooperation remained high. It was also found that pretreatment of the cells with another chemical, aldrin, exhibited the same pattern as the in situ TPA pretreatment effect on inhibition of metabolic cooperation. In order to obtain a high level of inhibition of metabolic cooperation when using aldrin in this assay, it was determined that the chemical needed to be present for more than one day. Our studies also showed that a 24 h treatment with 6-thioguanine did not kill 6-thioguanine-sensitive cells quickly, nor did it prevent them from performing metabolic cooperation. The relationship of cell density and TPA concentration was also studied. It was observed that a higher cell density required higher TPA concentration to inhibit, maximally, metabolic cooperation. A 'down regulation' type effect was noted when culture was challenged with different concentrations of TPA. These results were interpreted to be consistent with the hypothesis that inhibited gap-junctional intercellular communication is one of the components of tumor promotion.

Evaluation of prenatal aldrin intoxication in rats

The aim of the present study was to evaluate the impact of prenatal exposure to low doses of aldrin on physical and behavioral developments of rats (1-21 days old). To detect the possible persistent adversities produced by this exposure, the animals were also tested when adults (90 days old). Plasma determinations of both aldrin and its metabolite dieldrin and histopathological evaluations of brain slices were also performed in adult animals. Pregnant female rats were subcutaneously (s.c.) treated with aldrin (1.0 mg/kg) or with its vehicle (0.9% NaCl solution plus Tween-80) from day 1 of pregnancy until delivery. Results show that prenatal aldrin administration was able to decrease the median effective time (TE50) for incisor teeth eruption and to increase the TE50 for testes descent; other parameters indicative of physical development were not modified. Aldrin and dieldrin were not found in plasma of the adult rats; no differences were observed between control and experimental rats in the cellular and structural organization of the cerebral cortex neurones. Prenatal aldrin administration produced no impairment of adult animal's behavior in an avoidance learning test; nevertheless, the locomotor frequency of the experimental rats was higher than that of controls at 21 and 90 days old. When adults, these experimental rats had their performance in a hole-board apparatus (total number and duration of head-dips) also higher than that of the control ones. It was concluded that prenatal aldrin exposure induced not only developmental changes in the rat pups but also persistent behavioral alterations in adulthood, when the pesticide was not present in these animals.

A whole sample toxicity assessment to evaluate the sub-lethal toxicity of water and sediment elutriates from a lake exposed to diffuse pollution

The impact of diffuse pollution in aquatic systems is of great concern due to the difficult to measure and regulate it. As part of an ecological risk assessment (ERA), this study aims to use a whole sample toxicity assessment to evaluate the toxicity of water and sediment from Lake Vela, a lake that has been exposed to diffuse pollution. In this way, standard (algae: Pseudokirchneriella subcapitata; cladoceran: Daphnia magna) and local species (algae: Aphanizomenon flos-aquae; cladoceran: Daphnia longispina) were exposed to surface water, and sediment elutriates were collected seasonally from two sites at Lake Vela: one near the east bank (ES), surrounded by agricultural lands; and the other near the west bank (WS), surrounded by a forest. The results confirmed the seasonal contamination of both environmental compartments by pesticides, including organochlorine pesticides, and the presence of high concentrations of nutrients. Although both sites were contaminated, higher levels of pesticides and nutrients were detected in ES, particularly in the sediments. Bioassays showed that water samples (100% concentration) collected in summer and autumn significantly affected the growth rate of P. subcapitata, which could be attributed to the presence of pesticides. Likewise, they revealed an apparent toxicity of elutriates for P. subcapitata and for both daphnids, in summer and autumn. In fact, although pesticides were not detected in elutriates, high levels of un-ionized ammonia were recorded, which is considered highly toxic to aquatic life. By comparing the several species, P. subcapitata was revealed to be the most sensitive one, followed by the daphnids, and then by A. flos-aquae. Results obtained in this study underlined the importance of whole samples toxicity assessment for characterizing the ecological effects of complex mixtures from diffuse inputs, in the ERA processes.

Effect of aldrin on carbohydrate metabolism in Indian catfish

Exposure of the Indian catfish (Heteropneustes fossilis) to a sublethal concentration of 0.14 p.p.m. aldrin for 3, 6, 12, 48, and 96 hrs affected carbohydrate metabolism. Muscle glycogenolysis and glycogenesis were obtained at 3 and 12 hrs, respectively. Hepatic glycogenolysis occurred at 3, 48, and 96 hrs. The treatment caused hyperglycaemia at 3, 6, 48, and 96 hrs, and hypoglycaemia at 12 hrs. Blood pyruvate values increased significantly at 3, 6, and 96 hrs. Hyperlacticaemia was observed at 3 and 12 hrs but hypolacticaemia developed at 96 hrs. The results are discussed in relation to acute stress syndrome. Also, impairment of carbohydrate metabolism by aldrin may be involved in the biochemical mechanism for its toxic action. It is concluded that evaluation of carbohydrate metabolites in fish could prove useful as a rapid method for assessing acute toxicity of pesticides.

Significance of acute and chronic renal disease in Osborne-Mendel rats ingesting dieldrin or aldrin

Renal lesions developed in Osborne-Mendel male and female rats ingesting dieldrin or aldrin in the diet. Chronic interstitial nephritis was seen in rats surviving for 52 wk or longer. The incidence of nephritis was highest and the lesion was most severe in male rats given the higher dose levels of dieldrin, 50 ppm or higher. Over one-half of the rats fed dieldrin or aldrin at 150 ppm, and many fed 100 ppm, died from renal necrosis and sometimes hepatic necrosis during the first year. More female rats died from renal necrosis than did male rats. Rats dying from renal necrosis did not develop tumors; those from severe chronic nephritis either did not have tumors or had preneoplastic lesions that would have become tumors if the animal had lived longer. Thus acute and chronic effects should both be examined carefully when evaluating the safety of a chemical. In addition to causing the death of the animal, acute and chronic toxic effects can prevent the development of malignant tumors by shortening the animal's life span or by causing illness and inhibiting the development of a tumor that otherwise might occur in a healthy animal.

Cyclodiene organochlorine insecticide-induced alterations in the sulfur-redox cycle in CHO-K1 cells

The effect of the cyclodiene organochlorine pesticides aldrin, dieldrin and endosulfan was assessed on CHO-K1 cultures at fractions of their lethal doses, determined by the neutral red (NRI) incorporation assay (NRI6.25, NRI12.5 and NRI25). Glutathione peroxidase, reductase and S-transferase, and total and oxidised glutathione were evaluated along the standard growth curve of the cultures. After a 24-h incubation with each insecticide, glutathione peroxidase incurred a large increase, while glutathione reductase and S-transferase activities were slightly higher than untreated controls. Unlike oxidised glutathione, the content of total glutathione declined significantly after exposure to cyclodiene insecticides. Changes in cell membrane integrity were assessed by the lactate dehydrogenase (LDH) release assay and lipid peroxidation for a wide range of pesticide concentrations. Membrane leakage and peroxide production were significantly enhanced at concentrations of aldrin and as low as 12.5 microg/ml, whereas dieldrin and endosulfan increased membrane fragility at much higher concentrations.

Role of a γ-aminobutryic acid (GABA) receptor mutation in the evolution and spread of Diabrotica virgifera virgifera resistance to cyclodiene insecticides

The western corn rootworm, Diabrotica virgifera virgifera, is a damaging pest of cultivated corn that was controlled by applications of cyclodiene insecticides from the late 1940s until resistance evolved ∼10 years later. Range expansion from the western plains into eastern USA coincides with resistance development. An alanine to serine amino acid substitution within the Rdl subunit of the gamma-aminobutyric acid (GABA) receptor confers resistance to cyclodiene insecticides in many species. We found that the non-synonymous single nucleotide polymorphism (SNP) G/T at the GABA receptor cDNA position 838 (G/T(838)) of D. v. virgifera resulted in the alanine to serine change, and the codominant SNP allele T(838) was genetically linked to survival of beetles in aldrin bioassays. A phenotypic gradient of decreasing susceptibility from west to east was correlated with higher frequencies of the resistance-conferring T(838) allele in the eastern-most populations. This pattern exists in opposition to perceived selective pressures since the more eastern and most resistant populations probably experienced reduced exposure. The reasons for the observed distribution are uncertain, but historical records of the range expansion combined with the distribution of susceptible and resistant phenotypes and genotypes provide an opportunity to better understand factors affecting the species' range expansion.

Effects of endosulfan and aldrin on muscle coordination and conditioned avoidance response in rats

The deteriorative effects after chronic endosulfan exposure on muscle coordination, learning and memory of rats were compared with that produced by aldrin which has been reported to have similar effects in experimental animals. A rota-rod apparatus was used to study the muscle coordination and learning and memory were tested by recording the response to unconditioned and conditioned stimuli using a pole-climbing apparatus. Aldrin but not endosulfan inhibited motor coordination in both sexes. A greater motor deterioration occurred in male group. This finding, together with the previous data which shows inhibition by its metabolite of motor activity, suggests that its metabolic product is responsible for this action. Like aldrin, endosulfan inhibited both learning ability and conditioned avoidance response. A change in the activities of brain monoamines or inhibition of perception and reflexes or both were proposed for these behavioural effects, since the former was reported to be produced by both compounds and the latter was found to occur in aldrin treated rats.

Stoichiometric gene-to-reaction associations enhance model-driven analysis performance: Metabolic response to chronic exposure to Aldrin in prostate cancer

BACKGROUND

Genome-scale metabolic models (GSMM) integrating transcriptomics have been widely used to study cancer metabolism. This integration is achieved through logical rules that describe the association between genes, proteins, and reactions (GPRs). However, current gene-to-reaction formulation lacks the stoichiometry describing the transcript copies necessary to generate an active catalytic unit, which limits our understanding of how genes modulate metabolism. The present work introduces a new state-of-the-art GPR formulation that considers the stoichiometry of the transcripts (S-GPR). As case of concept, this novel gene-to-reaction formulation was applied to investigate the metabolic effects of the chronic exposure to Aldrin, an endocrine disruptor, on DU145 prostate cancer cells. To this aim we integrated the transcriptomic data from Aldrin-exposed and non-exposed DU145 cells through S-GPR or GPR into a human GSMM by applying different constraint-based-methods.

RESULTS

Our study revealed a significant improvement of metabolite consumption/production predictions when S-GPRs are implemented. Furthermore, our computational analysis unveiled important alterations in carnitine shuttle and prostaglandine biosynthesis in Aldrin-exposed DU145 cells that is supported by bibliographic evidences of enhanced malignant phenotype.

CONCLUSIONS

The method developed in this work enables a more accurate integration of gene expression data into model-driven methods. Thus, the presented approach is conceptually new and paves the way for more in-depth studies of aberrant cancer metabolism and other diseases with strong metabolic component with important environmental and clinical implications.

Comparative effects of structurally related cyclodiene pesticides on ATPases

Comparative effects of aldrin, dieldrin, endrin, isodrin and telodrin, on different ATPase activities in beef heart mitochondrial and rat brain synaptosomal fractions were determined in vitro. Beef heart mitochondrial fractions were prepared by the conventional centrifugation method and the rat brain synaptosomes were prepared by Ficoll-sucrose gradient centrifugation method. Na+-K+-ATPase, oligomycin-sensitive and -insensitive Mg2+-ATPases, and K+-paranitrophenylphosphatase were determined in rat brain synaptosomes. In beef heart mitochondria, only the Mg2+-ATPase activities were determined. Concentration response curves were determined by assaying the enzyme activities in the absence and presence of 10-120 microM concentrations of each test chemical. Beef heart mitochondrial (oligomycin-sensitive) Mg2+-ATPase activity was inhibited by all five chemicals at all the concentrations tested. Aldrin and telodrin were the most potent inhibitors with an IC50 of 40 and 80 microM, respectively. About 30% was observed with dieldrin, endrin and isodrin, and the inhibition was not concentration-dependent. Oligomycin-insensitive Mg2+-ATPase was not significantly inhibited by any chemical except aldrin. Rat brain synaptosomal ATPases were also sensitive to these compounds. Aldrin and telodrin were more effective than other compounds. A 50% inhibition of oligomycin-sensitive Mg2+-ATPase activity was obtained at 80 microM of aldrin and telodrin. Na+-K+-ATPase and oligomycin-insensitive Mg2+-ATPase activities showed a maximum inhibition of 40% at the highest concentration tested for aldrin and telodrin. K+-paranitrophenylphosphatase was not inhibited significantly by any compound tested. These results suggest that ATPase system in rat heart and CNS may be selectively inhibited by aldrin and telodrin, but not by their structural analogs.

Toxicological significance of dihydrodiol metabolites

Dihydrodiols are often found as the major organic-extractable metabolites of various olefinic or aromatic xenobiotics in many biological samples. Studies on the chemistry of dihydrodiol metabolites have provided insight into the pharmacokinetic behavior and the mode of action of the parent compound. The toxicology of dihydrodiol is more complex than what can be deduced solely on the basis of diminished bioavailability of the epoxide precursor, and the increased hydrophilicity associated with the dihydrodiol moiety. Dihydrodiols can be intrinsically toxic and may even represent metabolically activated species. Some of the dihydrodiol metabolites may still retain sufficient lipophilic character to serve again as substrates for microsomal oxygenases. Because of the tremendous chemical and biological diversity that existed among the various dihydrodiols, more mechanistic studies are needed to examine the toxicological properties of these compounds. It may be premature to conclude dihydrodiol formation as purely a detoxification route for xenobioties.

Toxicological profile of organochlorines aldrin and dieldrin: an Indian perspective

Several epidemiological studies have suggested various environmental factors as a possible cause for increased incidence of various abnormalities. Of the various environmental contaminants, the most prevalent and the most discussed are the endocrine disrupting chemicals. Contact of such disruptors with humans has become inevitable today. They are cosmopolitan and present from agriculture to industrial sectors, even in day-to-day consumer products. Aldrin and dieldrin belong to one such class of substances which are known to have a toxic effect on various physiological systems of the human body. Despite an imposed ban on their manufacture and commercial use, these pesticides could still be detected in probable areas of consumption like agriculture. The present review discusses the known possible toxic effects of aldrin and dieldrin and their current existence in the ecosystem across India.

The effects of a few xenobiotics on certain phosphatases in the plasma of Clarias batrachus and Cirrhina mrigala

The effects of sublethal concentrations 1/2, 1/4 and 1/8 fractions of 96-h LC50 of aldrin and Swascofix CD-38 on alkaline, acid and glucose-6-phosphatases in the plasma of Clarias batrachus and Cirrhina mrigala were studied. These enzymes increased after exposure of fish to both xenobiotics. The increase was maximal after 20 days exposure to the highest concentrations. The enzyme increase was greatest in the fish exposed to aldrin.

Biomarkers of oxidative stress in Wallago attu (Bl. and Sch.) during and after a fish-kill episode at Panipat, India

The present investigation was carried out by sampling water, sediment and fish during a fish-kill episode at Panipat (Haryana, India), and again sampling at the same site was conducted after a gap of two months. During the second sampling no fish-kill was observed and the water was relatively less turbid and clear. Antioxidant profile and lipid peroxidation (LPO) in fish tissues were studied. Analysis was also carried out on the physico-chemical characteristics of water samples along with heavy metal and pesticide analysis in water and sediment samples during and after the episode. Dissolved oxygen level was substantially low during the fish-kill episode. Heavy metals (copper and chromium) and pesticides like BHC (Benzene hexachloride), DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane) were also detected during the episode in water and sediment samples. Various oxidative stress biomarkers in liver, kidney and gill tissues in the Indian freshwater fish Wallago attu (Bl. and Sch.) collected from the site were investigated. The levels of reduced glutathione and non-protein thiol were significantly (P<0.001) higher in the liver of Wallago attu collected from Panipat after the fish-kill episode. Ascorbic acid levels in all the tissues did not change significantly after the episode. The LPO in liver, kidney and gills was significantly low (P<0.01-0.001) in all tissues of fish collected after the fish-kill episode. The protein carbonyl levels were significantly low (P<0.05-0.01) in all the fish organs sampled after the fish-kill episode. The findings suggest that industrial effluent may result in the massive loss of a commercial commodity. The simultaneous measurement of the physicochemical parameters of the water samples showed a good correlation between the biomarkers responses and the environmental chemical stress conditions.