首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 78 毫秒
1.
Nile Tilapia (Oreochromis niloticus) juveniles were exposed to different concentrations of Folidol 600® in static toxicity tests. The 24, 48, 72 and 96 h LC50 values of Folidol 600® to O. niloticus were 17.82, 8.91, 4.00 and 2.70 mg L−1, respectively. The values of hematological parameters increased, and inhibition of cholinesterases activity (AChE, BChE and PChE) in plasma of fish exposed to the higher concentrations of pesticide reached 94%. Furthermore, the exposure of Tilapia to Folidol 600® caused an increase of 4%, 20% and 38.4% in oxygen consumption at 0.1, 0.5 and 1.0 mg L−1, respectively. However, exposure to 2.5, 5.0 and 10 mg L−1 caused a decrease of 33.6%, 35.2% and 42.4% in oxygen consumption relative to the control. The ammonium excretion of fish exposed to 0.0, 0.1, 0.5, 1.0, 2.5, 5.0 and 10.0 mg Folidol 600®/L was 0.12, 0.18, 0.30, 0.33, 0.37, 0.36 and 0.33 μg/g/min, i.e., 50%, 150%, 175%, 208%, 200% and 175% increase, respectively, relative to the control.  相似文献   

2.
Diethyl phthalate (DEP) enter into aquatic environment from industries manufacturing cosmetics, plastic and many commercial products and can pose potential fish and human health hazard. This experiment evaluated effects of DEP in adult male (89 g) common carp (Cyprinus carpio) by exposing them to fractions of LC50 (1/500-1/2.5) doses with every change of water for 28 days. Vitellogenin induction metabolic enzymes, somatic indices and bioaccumulation were studied on 7th, 14th, 21st and 28th day. The 96th hour LC50 of DEP in fingerlings was found to be 48 mg/L. Compared to control, except increase (P < 0.01) in alkaline phosphatase activity (EC 3.1.3.1) and liver size, there was decrease (P < 0.01) in activity of acid phosphatase (EC 3.1.3.2), aspartate aminotransferase (EC 2.6.1.1), alanine aminotransferase (EC 2.6.1.2) and testiculosomatic index following exposure to 1, 5 and 20 ppm DEP. Significant (P < 0.01) dose dependant vitellogenin induction was observed with exposure of fish to 0.1, 1 and 5 ppm DEP. The bioaccumulation of DEP in testis, liver, brain, gills and more importantly in muscle tissues of fish increased significantly (P < 0.01) with increase of dose from 1 to 5 ppm. Significant interaction (P < 0.01) of dose and duration of exposure indicated that exposure period of a week to two was sufficient to bring about changes in quantifiable parameters studied. Fish exposed to 20 ppm DEP became lethargic and discolored during onset of the 4th week. This is the first report describing metabolic changes and vitellogenin induction following exposure of C. carpio to DEP dose that is as low as 1/500th fraction of LC50.  相似文献   

3.
The hormone profile of Sarotherodon mossambicus (Peters) under endosulfan (an organochlorine pesticide) toxicity was investigated by estimating the serum levels of T3 (triiodothyronine), T4 (thyroxine), cortisol, prolactin and insulin in control and sub-lethal (0.001 mg L−1) endosulfan-exposed fish for 1, 6, 12, 24 h and 5 days. Exposure of fish to sub-lethal concentration of endosulfan caused varying changes in the levels of serum hormones studied. Based on the results obtained, it was concluded that (i) the fish registered an increased metabolic activity during the initial period followed by an adaptive lowering of metabolic rate as indicated by changes in the serum T3 and T4 levels, (ii) the fish showed an adaptive stress response as indicated by the reduced cortisol level which could be probably due to severe interrenal exhaustion, (iii) the increased serum prolactin levels in the fish under endosulfan exposure is indicative of a possible action of prolactin on gills and kidney towards hydromineral regulation in the fish body under pesticide stress, (iv) the fish adaptively increases its serum insulin level thereby registering a possible adaptive hypoglycemic role of the hormone to favour the transport of glucose to different tissues besides a possible lipogenic activity of the higher insulin level in fish tissue under pesticide toxicity and (v) the fish appears to exhibit a possible adaptive recovery response in its hormone profile following prolonged exposure for 24 h and 5 days.  相似文献   

4.
In the present study, the toxic effects on the embryos and larvae of the common carp were used as a model to investigate the organophosphorus pesticide, diazinon, which contaminates aquatic ecosystems. Data obtained from the diazinon acute toxicity tests were evaluated using the Probit Analysis Statistical Method. The control and six test experiments were repeated five times. The number of dead embryos significantly increased in response to diazinon concentrations 0.25, 0.5, 1, 2, 4, and 8 mg L−1 (p < 0.05 for each case). The 48 h LC50 value (with 95% confidence limits) of diazinon for common carp embryos was estimated at 0.999 (0.698-1.427) mg L−1. Dose-response decreases in hatching success were recorded as 84.60, 75.2, 54.1, 31.0, 6.0, and 0.0%, respectively (p < 0.05). The number of dead larvae significantly increased with increasing diazinon concentrations exposed for 24-96 h (p < 0.05). The 24, 48, 72, and 96 h LC50 values (with 95% confidence limits) of diazinon for common carp larvae were estimated at 3.688 (2.464-8.495), 2.903 (2.019-5.433), 2.358 (1.672-4.005), and 1.530 (1.009-3.948) mg L−1, respectively. There were significant differences in the LC50 values obtained at different exposure times (p < 0.05). The results of the study suggest that low levels (0.25 mg L−1) of diazinon in the aquatic environment may have a significant effect on the reproduction and development of carp.  相似文献   

5.
The present study was conducted to determine the 96 h-LC50 of benomyl to the Nile tilapia, Oreochromis niloticus and to investigate the biochemical or hematological indices of blood and the alterations in the antioxidant enzymes of this fish in response to sublethal concentrations of benomyl. Fish weighing 71.61 ± 12.05 g were used in this study; they were subjected to fasting for 4 weeks before treatment. An aqueous solution of benomyl (0, 0.5, 1, 2, 4, 8, and 16 mg L−1) was administered for 96 h to determine the LC50. The 96 h-LC50 value of benomyl was 4.39 (3.23-5.60) mg L−1 in the present study. For 5 weeks, the aqueous solution of benomyl (0, 100, 200, and 400 μg L−1) was administered to investigate its effect on the hematological parameters and antioxidant enzymes. The predominant hematological findings in fish exposed to benomyl were as follows: no significant change in the Hb (g dL−1) level, MCV (μm3), MCH (pg) and MCHC (%) as compared to the control. Benomyl exposure led to greater increases in the GPT, GOT (Karmen-unit), LDH (Wroblewski unit), total cholesterol, Fe, and Ca (mg dL−1) values, whereas the levels of ALP (KA unit), total protein, triglyceride, albumin, and Mg (mg dL−1) did not increase. Benomyl increased the in vivo HSI (%), GST (nmol min−1 mg protein−1), and SOD (U mg protein−1) values in the fish livers in the test group, unlike those in the control group for 5 weeks. At concentrations higher than 100 μg L−1, benomyl affected the GST and SOD levels of Nile tilapia in a dose- and time-dependent manner. The present findings suggest that the in vivo hepatotoxicity associated with benomyl may, in part, result from the hematological index, and antioxidants may provide limited protection against benomyl toxicity.  相似文献   

6.
Organophosphothionate insecticide fenitrothion is known as potential toxic pollutant contaminating aquatic ecosystems. The effects of fenitrothion were studied to determine the 96 h LC50 value on Nile tilapia (Oreochromis niloticus) and investigate histopathological responses of fish exposed to sublethal fenitrothion concentrations. Data obtained from the fenitrothion acute toxicity tests were evaluated using the Probit Analysis Statistical Method. The 96 h LC50 value and 95% confidence limit for Nile tilapia (58.70 ± 6.97 g) was estimated as 0.84 (0.68-1.15) mg/L. Behavioral changes were observed closely during the acute toxicity test. The bioassay experiments were repeated three times and static test method was used. Some fish exposed to 96 h 0.1, 0.5 mg/L fenitrothion concentrations showed histopathological alterations in the gills, liver, kidney, brain and testes. Severely deformations were observed at 0.5 mg/L fenitrothion on the gills lamella such as hyperemia, epithelial hyperplasia, fusion and telangiectasis, in the liver tissue such as cloudy swelling, hydropic degenerations and lipid infiltration. In addition hyperemia and hemorrhage observed in kidney tissue and hyperemia was determined in brain tissue.  相似文献   

7.
Endosulfan is an organochlorine pesticide widely used in agriculture and hence finds its way into natural water bodies, thus affecting aquatic life. The purpose of this study was to determine LC50 of endosulfan (99%; α:β ratio of 7:3) in Tilapia, Oreochromis mossambicus and study its effect on anti-oxidative enzymes (superoxide dismutase, glutathione-S-transferase and catalase), immuno-hematological profile (RBC, WBC, Hb, serum protein, albumin-A, globulin-G, A/G ratio, phygocytic activity as indicated by nitroblue tetrazolium reduction, serum cortisol and serum lipid peroxidation) and neurotransmitter acetylcholine esterase enzyme activity. The LC50 value at 96 h and 95% confidence limit for tilapia (46.78 g) was estimated as 3.6 μg/L. Activities of anti-oxidative enzymes, immuno-hematological profile, blood glucose and neurotransmitter activity was significantly influenced (P < 0.01) in dose dependent manner. This was reflected in the behavior of fish that was altered from normal during acute toxicity.  相似文献   

8.
We investigated the endocrine disrupting effects of chlorpyrifos-ethyl which is suspected to be originated from oxidative stress. Initially, the 96 h LC50 values of chlorpyrifos in juvenile and adult of Oreochromis niloticus were determined to be 98.67 μg/L and 154.01 μg/L, respectively. Sub-lethal concentrations of chlorpyrifos-ethyl (5 ppb, 10 ppb, 15 ppb) were administrated to adult fish for 15 and 30 days. Fish were then left to depurate for 15 days in pesticide-free water. Gonadal somatic indices, serum sex steroids as indicators of reproductive function and cortisol level as indicator of stress condition were measured to observe the endocrine disruption effects of chlorpyrifos-ethyl. Gonadal glutathione S-transferase and antioxidant enzyme activities and lipid peroxidation as indicators of oxidative stress were also measured. Acetylcholinesterase activity was measured as a marker of chlorpyrifos toxicity. Results showed that serum estradiol, testosteron and cortisol levels in fish exposed to chlorpyrifos were lower than those of the control fish while gonad somatic indices did not change during the experiments. After 30 days, chlorpyrifos exposure decreased GST activity, and increased SOD enzyme activity by up to 215-446% compared with the control, suggesting there was a oxidative stress. No statistically significant differences between GPx and CAT specific activities, protein contents and lipid peroxidation were determined between control and treatment groups in all exposure concentrations and periods. Acetylcholinesterase activity decreased (45.83-77.28%) in gonad tissues. After recovery serum estradiol and testosteron levels were similar to those of the control levels. An increase in the GST and SOD enzyme activities were determined. Cortisol level and AChE activity in all exposure groups decreased after the depuration period, and fish were unable to overcome the stress of chlorpyrifos. Thus, this study revealed that after chlorpyrifos treatments there exists a protective function of antioxidant enzymes against lipid peroxidation in gonad tissue of O. niloticus. There also exist lower testosteron and estradiol levels in exposed fish than those of the control fish without any alterations in oxidative stress, which is attributed to the capability of chlorpyrifos to impair steroid hormone levels.  相似文献   

9.
Of the huge annual worldwide production (500,000 MT in 1997) of alkylphenol polyethoxylates (APEs) that are widely used as nonionic surfactants and anti-oxidants in variety of products, 60% ends up in water bodies. They undergo biodegradation to form octyl-, butyl-, and nonyl-phenols. This experiment evaluated effects of 4-tert-butyl phenol (4-TBP) in Cyprinus carpio, a projected candidate species in sewage fed fisheries. The 96th h LC50 of 4-TBP was found to be 6.9 mg/L. Fishes were treated with 1/10th (0.69 mg/L), 1/5th (1.38 mg/L), and 1/3rd (2.3 mg/L) dose of LC50. Whereas there was significant (P < 0.01) decrease in alkaline phosphatase [EC 3.1.3.1] and aspartate aminotransferase [EC 2.6.1.1] activity; alanine aminotranferase [EC 2.6.1.2] and acid phosphatase [3.1.3.2] (except decrease at 1/10th dose of LC50) activity, vitellogenin production in muscle and hepatic- and reno-somatic indices were increased compared to control. With all the dose levels tested, testicular-somatic index (testis size) was reduced (P < 0.01) and histo-architectural changes in testicular and liver tissue were found even in group given 1/3rd dose of LC50.  相似文献   

10.
Freshwater fish, Channa punctatus, commonly known as the snakehead fish, was exposed to two sublethal concentrations (0.96 and 1.86 mg/L) (selected on the basis of 1/20 and 1/10 of 96 h LC50 value) of monocrotophos for two exposure periods (15 and 60 days). Effects of monocrotophos on Na+, K+-ATPase in liver, kidney, muscle, intestine, brain, heart and gills were determined. Results indicate that Na+, K+-ATPase activity in tissues decreased as concentration of monocrotophos and exposure period increased. Monocrotophos induced significant inhibitory effects on the Na+, K+-ATPase activity of C. punctatus, ranging from gills (70%) > Kidney (63%) > brain (57%) > intestine (52%) > liver (50%) > muscle (47%) > heart (44%) inhibition at a sublethal concentration of 0.96 mg/L. Significant inhibition was detected in Na+, K+-ATPase activity, ranging from gills (90%) > heart (78%) > kidney (78%) > muscle (74%) > intestine (71%) > brain (67%) > liver (63%) at sublethal concentration of 1.86 mg/L. After subacute exposure (15 days) only gills and brain showed significant inhibition after higher concentration (1.86 mg/L). However, it is evident that exposure duration is more important than dose in the inhibition of the activity of enzyme. At lower concentration initial stimulation of the activity of Na+, K+-ATPase activity was also noticed. It is suggested that the inhibition of the ATPase by monocrotophos blocked the active transport system of the gill epithelial as well as chloride cells, glomerular and epithelial cells of the tubules and thus altered the osmoregulatory mechanism of the fish. In fact, the impairment of the activity of enzymes which carry out key physiological roles could cause alterations of the physiology of the whole organism.  相似文献   

11.
Diazinon is commonly used for pest control in the agricultural fields surrounding freshwater reservoirs. So this study was conducted to determine the acute toxicity of this organophosphorous pesticide, contaminating aquatic ecosystems as a pollutant, and its effects on behavior, and some hematological parameters of fingerling European catfish, Silurus glanis. Diazinon was applied at concentrations of 1, 2, 4, 8, 16, 32, and 64 mg L−1. The water temperature in the experimental units was kept at 16 ± 1 °C. The number of dead fishes significantly increased in response to diazinon concentrations 2-64 mg L−1 (p < 0.05). With increasing diazinon concentrations, the fishes exposed duration 1 to 96 h significantly increased the number of dead fishes (p < 0.05 for each cases). The 1, 24, 48, 72, and 96 h LC50 values (with 95% confidence limits) of diazinon for fingerling European catfish were estimated as 14.597 (12.985-16.340), 12.487 (11.079-14.471), 8.932 (7.907-10.348), 6.326 (no data because of p > 0.05), and 4.142 (no data because of p > 0.05) mg L−1, respectively. Compared to the control specimens, fish after an acute exposure to diazinon was significantly lower erythrocyte, leukocyte, hemoglobin, hematocrit, MCV, MCH, and MCHC values (p < 0.05). In addition, it was also showed a significantly negative correlation between these hematological parameters and exposure times of diazinon (p < 0.01).  相似文献   

12.
Experiment was carried out to determine the median lethal concentration (LC50) of fenvalerate to Labeo rohita fingerlings. After determining the LC50 value of fenvalerate, a sub-lethal concentration (1/3rd of LC50) of fenvalerate was exposed for 15 days. Significant alterations in SOD (P < 0.05) activity of liver and gill was observed due to fenvalerate. Catalase activity in gills of fishes was also affected significantly (P < 0.05). WBC, NBT and Hct values were reduced significantly in fenvalerate exposed fishes as compared to control group, whereas blood glucose level showed higher values in fenvalerate exposed group. Serum total protein and albumin were also reduced significantly as a result of fenvalerate exposure. Significant increase in the serum GOT, serum GPT, creatinine, triglyceride and serum ACP was noticed after 15 days of fenvalerate exposure. Results indicated that short term exposure of fenvalerate can induce biochemical and haematological alterations causing stress to L. rohita fingerlings.  相似文献   

13.
The results showed that survival rates of Biomphalaria alexandrina snails, reproductive potential and hatchability of eggs were evaluated post exposure to Basudin, Selecron and Colchicine. As well, DNA and RNA changes in the cells of ovotestis-digestive gland complex of treated snails were estimated. The current molluscicide Bayluscide was used as a reference compound.The pesticide Selecron proved to be more toxic to B. alexandrina snails than Basudin and Colchicine. Juvenile snails were dead post 3 weeks of exposure to the sublethal concentration LC0 of either Selecron or Basudin, while 26.75% of snails still alive at Bayluscide treatment. In addition, exposure of adult snails to LC0 of Selecron for 24 h/week for 4 weeks markedly reduced their reproductive rate (R0) by 89.9%. Moreover, snails’ eggs failed to hatch post 24 h of exposure to LC90 of either Selecron, Basudin or Bayluscide. Electrophoretic analysis indicated a decrease in the molecular weight of intact DNA in the ovotestis-digestive gland complex of snails treated with 250 ppm of Colchicine and LC25 of Selecron, as it scored 1.2 and 76 bp, respectively, compared to 166.46 bp for control group, while the vice versa was recorded for RNA intensity. It was concluded that the tested pesticides have deleterious effects on snails’ reproductive rate, their eggs and the intensities of DNA and RNA in their ovotestis-digestive gland complex. Therefore, it is expected that reaching of such pesticides to snails’ habitats in water courses during plant pests control could minimize the population density of the snails intermediate hosts of schistosomiasis, hence probably interrupt and reduce the transmission of this parasite.  相似文献   

14.
The acute 96 h LC50 of (2,4-dichlorophenoxy)acetic acid (2,4-D), a widely used agricultural herbicide, was determined on crayfish (Astacus leptodactylus Esch. 1823). Crayfish of 23.5 ± 1.49 g mean weight and 9.6 ± 0.21 cm mean length were selected for the bioassay experiments. The experiments were repeated three times, in 10 L tap water. The data obtained were statistically evaluated by the use of the E.P.A computer program based on Finney’s probit analysis method and the 96 h LC50 value for crayfish was calculated to be 32.6 mg/L in a static bioassay test system. 95% lower and upper confidence limits for the LC50 were 15.10-327.16. In conclusion, 2,4-D is highly toxic to crayfish, a non-target organism in the ecosystem. Water temperature was 23 ± 1 °C. Behavioral changes of crayfish were recorded for all herbicide concentrations.  相似文献   

15.
Exposure of the Indian catfish (Heteropneustes fossilis) to a high sublethal concentration, 0.114 ppm (0.8 of the 96-hr LC50) of a mixture of aldrin and formothion, added in a one-to-one ratio, for 3, 6, 12, 48, and 96 hr affected carbohydrate metabolism. Muscle glycogen decreased significantly at 6 and 48 hr; hepatic glycogen content declined at 3, 6, 12, and 48 hr in exposed fish. Blood glucose levels in fish were significantly decreased at 3, 12, 48, and 96 hr. Mean value of blood pyruvate was significantly depressed at 3 hr. Blood lactate levels were elevated at 3, 6, 12, and 96 hr in pesticide-treated fish. The observed effects of the mixture of aldrin and formothion on carbohydrate metabolism in fish could prove useful as a rapid method for evaluating toxicity of pesticides and other toxicants.  相似文献   

16.
Four extracts of Arisaema erubescens tubers by acetic acetal (AAE), benzinum (BZE), n-butanol (NBE) and chloroform (CFE) were obtained to evaluate their molluscicidal activities against the snail Oncomlania hupensis. The responses of choline esterase (ChE), alkaline phosphatase (ALP), esterase (EST), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) to the extracts (NBE) were also investigated. In the four extracts (AAE, BZE, NBE and CFE), NBE showed the highest toxicity on the snails after 48 h exposure. NBE also showed the time- and concentration-dependent effect, for example, the LC90 values of the NBE were decreased from 365.5 mg/L (24 h) to 36.4 mg/L (96 h). At the end of exposure to NBE (LC50 concentration), the activities of ChE and ALP in snail tissues (cephalopodium and liver) decreased significantly. Isozyme electrophoresis profiles indicated that responses of isozymes (EST, SOD and GSH-Px) to NBE were more intense in liver than in cephalopodium. After 72 h exposure to NBE, the EST activity in snail liver decreased and some enzyme bands (EST1 and EST4) disappeared. But the activities of SOD 1 and GSH 2 in liver increased after 48 h exposure. The results indicated that NBE was the highest toxic component in the four extracts. The decline of the detoxification ability and the oxidative damage in snail tissues might be the main reason for the molluscicidal activities.  相似文献   

17.
The individual and combined effects of dimecron (an organophosphate pesticide) and ziram (a carbamate fungicide) on the levels of serum prolactin and selected minerals (Ca, P, and Mg) are studied in an edible freshwater fish, Oreochromis mossambicus (Peters) exposed to sub-lethal concentrations of individual dimecron (0.002 mL L−1) and ziram (0.008 mL L−1) and combined 1:4 mixture of dimecron-ziram (0.01 mL L−1) for 24, 48, and 72 h. Exposure of fish to sub-lethal concentration of individual and mixture of dimecron and ziram caused changes in the levels of serum prolactin and minerals studied compared to control fishes. Based on the results obtained, it was concluded that the individual exposures of dimecron and ziram comparatively manifested higher toxic effects (than the combined exposure) by reducing prolactin levels and loss of mineral contents. These changes may result in a severe osmoregulatory problem.  相似文献   

18.
In Asia, Monopterus albus (Asian swamp eel) is commonly found in rice fields, muddy ponds and swamp areas. Because of its habitat, it is exposed to toxic pesticides used in rice fields, especially endosulfan, which is one of the most widely used insecticides. This study aims to determine the acute toxicity of endosulfan and its effect on the behaviour and some hematological parameters of the fish. The 96 h-LC50 (with 95% confidence limits) obtained in this study for M. albus was 0.42 (0.35-0.50) μg L−1. After 96 h exposure to endosulfan, the fish exhibited a series of abnormal behavioural responses; these included imbalanced position, restlessness of movement, erratic swimming, tremor, flashing and lethargy. When the swamp eels were exhausted, they were laterally recumbent on the bottom and had no opercula movement. Endosulfan toxicity also caused a significant lower (p < 0.05) value of erythrocyte count, leukocyte count, hemoglobin and hematocrit as compared to the control experiment. Nevertheless, the erythrocyte cell showed an increasing trend in size. The swollen erythrocyte cells may be impaired in their oxygen-carrying capacity. Severe blood loss through the gill capillary and hematemesis of the fish may be the main reasons for the hematological changes in the test organisms. Despite its relatively bigger size (30-40 cm in length) as compared to most of the other test organisms (<5 cm in length) for endosulfan toxicity, it is interesting to find that this fish is one of the most sensitive freshwater fishes to endosulfan.  相似文献   

19.
Tests of acute toxicity were performed on the most common species of aquarium fish, Poecilia reticulata. Guppies (P. reticulata) were exposed to progressive concentrations of methyl parathion (MP) and chlorpyrifos (CPF); a semi-static method according to guidelines of OECD was used. Tests of acute toxicity were conducted using 10 fish for each separate concentration and for the control group. The results were subjected to probit analysis to determine the 96 h LC50 values. The 96 h LC50 values of MP and CPF to P. reticulata were 8.48 ppm/L (5.98–10.89) and 0.176 ppm/L (0.313–0.224) respectively. In addition, behavioral changes at each concentration were observed for the individual fish. Fish were exposed for 96 h to different sublethal concentrations of MP and CPF (¼ LC50, 1/8 LC50 and 1/10 LC50) and their oxidative stress-induction potential was estimated in brain, liver and gills of fish. MDA content is induced in all tissues but maximum rise was observed in gills (161% and 153% for MP and CPF respectively). With regard to antioxidant defense system (ADS), GSH level decreased in the brain, liver and gills of tissues of MP treated fishes (22%, 6% and 13% respectively) and showed increase in brain and gills CPF treated (23% and 21% respectively). CAT, GST, GR and SOD levels fluctuated in all treatment groups relative to the control. Brain AChE showed dose-dependent inhibition in fish exposed to the higher concentrations reached 45% and 66% for MP and CPF respectively. Collective findings demonstrated that pesticide exposure of fish induced an increase in MDA and fluctuated ADS along with inhibited AChE. These findings may be used as valuable biomarkers for evaluation of water pollution.  相似文献   

20.
The continuous increase in the number of new chemicals as well as the discharges of solid and liquid wastes triggered the need for simple and inexpensive bioassays for routine testing. In recent years, there has been increasing development of methods (particularly rapid tests) for testing environmental samples. This paper describes the quick toxic evaluation of an organophosphorus insecticide, acephate (O,S-dimethyl acetylphosphoramidothioate) on Paramecium caudatum for acute and sub-acute toxicity studies with reference to morphology, behaviour, and its generation time. The lethal concentrations for 10 min and 2 h were determined by probit method, as 500 mg L−1 and 300 mg L−1, respectively. Higher concentrations of 10 min exposure caused cell lysis with disintegration of cell membrane and precipitation of protoplasm. Combination of conventional light microscopy and computerized video tracking systems were used to study the locomotor behaviour of paramecia. The test organism was under stress and exhibited an initial increase and subsequent decrease in the swimming speed when exposed to 1/4, 1/2, 3/4, and LC50 concentrations for 10 min (125, 250, 375, and 500 mg L−1, respectively). Similar changes were also noticed when paramecia were exposed to LC50 for 2 h. In a separate set of experiments, the number of generations and generation time in 24 h was evaluated with respect to the different sub-lethal concentrations (30, 60, 120, and 240 mg L−1). The number of generations decreased and generation time extended significantly in a concentration dependent manner. The results indicate that the Paramecium toxicity assay could be used as a complimentary system to rapidly elucidate the cytotoxic potential of insecticides. The major advantages associated with these tests are: they are inexpensive, simple, user-friendly, space saving, and seem to be attractive alternatives to conventional bioassays.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号