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 15 毫秒
1.
The LC50 of Malathion for Channu punctatus is determined for 24… 96 h of exposure as 10.95… 3.22 mg/l. At exposure to 2.5 mg./l Malathion, growth–measured by increase in weight–is significantly reduced from the 19th day and reduced by 10 % till the 31st day. During the same period of time, the RNA and protein contents of the muscle is lowered by 10 and 15 %, respectively, as compared with the control. In addition to an acute toxic effect, in sublethal concentrations Malathion has also pronounced effects on growth and metabolism.  相似文献   

2.
Static bioassay tests were carried out on Channa punctatus Bloch in the laboratory after renewal of concentrations every 24 h. The LC50 values and 95 per cent confidence limits were 45.21 (39.62 … 51.11) ppm at 12 h and 29.8 (27.49 … 31.95) ppm of Zn at 96 h of exposure. The actual dissolution values of zinc were also determined in test solutions using an atomic absorption spectrophotometer. Behavioural changes were the higher rate of opercular movements, surfacing, loss of equilibrium and haemorrhage near mouth and caudal fin. The LT50 values indicate that survival was increased with decreasing Zn concentration. The histopathological changes observed due to Zn toxicity in the gills have been discussed in relation to fish mortality.  相似文献   

3.
The LC50-values of As3+-compounds for Channa punctatus are determined for a 48-h exposure to 19.4 (18.02… 21.3) mg/1 and for a 96-h exposure to 14.3 (13.06… 16.80) mg/1. At a long-time exposure to 7.0 mg/1 As3+, during the first seven days there does not occur any change of growth, then the growth in length and the increase in weight decreased by 6.6 and 11.7%, respectively, till the 31st day. At the same time, the RNA content of the muscle decreased by 11.5% to 966.7 μg/g fresh weight and the protein content decreased by 12.5 % to 95.39 mg/g fresh weight.  相似文献   

4.
The haematological, biochemical, and enzymological alterations produced on exposure of Channa punctatus to LC50 (11.2 mg/L) for 96 h and to a sublethal concentration (1.12 mg/L) of cadmium (Cd2+) for 15, 30, 60, and 120 days have been studied. The fish were hypoglycemic and hypolactemic. The pyruvate content of blood and liver decreased in acute and all stages of chronic exposure except for 30 days where significant increase was recorded. Depletion was noted in the total protein and glycogen content of liver and muscle, and the level of lactate in liver in the two types of exposure. The levels of muscle lactate and pyruvate increased in both exposures. The activities of hexokinase, glucose-6-phosphatase, and lactate dehydrogenase decreased in liver after 96 h and all stages of chronic exposure except 30 days. The activities of hexokinase and lactate dehydrogenase in muscle and glutamate-oxalacetate transaminase and glutamate-pyruvate transaminase in serum, liver, and muscles increased in all exposures. The activities of succinate and malate dehydrogenases in liver and muscles decreased after acute and all stages of chronic exposure. The above results suggest that glycolysis and gluconeogenesis were impaired in liver but glycolysis prevailed in muscle. Aerobic oxidation is adversely affected in metal exposed fish, while proteolysis was increased.  相似文献   

5.
Static bioassay acute toxicity tests of Zinc, Copper and Mercury were conducted to determine the median lethal concentrations (LC50s) of a freshwater teleost Channa marulius (HAM .) The 96 h LC50 and 95% confidence limits for Zn2+ were 25.61 (24.13 … 27.12) mg/l; 0.90 (0.80 … 1.038) mg/l; for Cu2+ and 0.314 (0.257 … 0.371) mg/l for Hg2+. However, these values decreased at 240 h of exposure and were: 21.09 (18.29 … 24.60) mg Zn2+/l; 0.66 (0.568 … 0.841) mg Cu2+/l; and 0.131 (0.103 … 0.158) mg Hg2+/l. The relative potency ratio of Zn/Hg, Zn/Cu and Cu/Hg suggests that fish were most sensitive to Hg, followed by Cu and Zn ions. The acute toxicities of mixtures of Zn2+?Cu2+; Zn2+?Hg2+, Cu2+?Hg2+ and Zn2+?Cu2+?Hg2+ up to 48 h of exposure were also investigated. The additive index and ranges for Zn2+?Cu2+ were ?0.241 (-0.577 … 0.054); 0.056 (-0.269 … 0.475) for Zn-Hg; 0.285 (-0.043 … 0.718) for Cu-Hg; and -0.542 (-1.215 … 0.005) for Zn-Cu-Hg. All the mixtures tested showed a greater than additive toxicity because index ranges overlapped zero.  相似文献   

6.
The freshwater catfish, Mystus vittatus, were exposed to the LC50, 96 h dose (i.e. 550 ppm.) of the agro-fertilizer NPK for 96 h, during the spawning period (March–June). Their gonads were biochemically analysed for the total protein content and the free amino acids. The protein content of the gonads of the stressed fish was found lowered. The fish also showed disappearence of certain amino acids from their gonads.  相似文献   

7.
Effects of acute cadmium poisoning on survival, its residual values and histopathology in certain organs of a freshwater airbreathing fish, Channa punctatus (BLOCH ) were investigated. The threshold concentration, MATC and LC50 values obtained from 96 h static bioassay, revealed that Channa is more susceptible to cadmium ions at higher temperature. The atomic absorption spectrophotometric determination of cadmium residues differed significantly in organs of specimens having survived and died after 96 h of exposure. The gill accumulate the highest amount of cadmium, the liver accumulated a slightly smaller amount than the gill, while the kidney accumulated the least. The histopathological lesions subjected to sublethal (5.2 mg/l Cd) and lethal (8.4 mg/l Cd) concentrations of cadmium were: detachment and rupture of lamellar epithelium, collapse of pillar cells and hypertrophy in mucus producing gland cells in the gill; vacuolization and coagulative necrosis in hepatic cells of the liver; and expansion, necrosis and accumulation of cellular debris in renal tubules of the kidney. The probable causes for death of fish due to cadmium ions have been discussed.  相似文献   

8.
Median times to narcotization (ET50) of Cirolana borealis Lilljeborg by various levels of toluene in seawater were determined. Narcotization quickly became irreversible, and the ET50 values can be regarded as estimates of median lethal times. Respiratory rate, ATP concentration, and energy charge (E.C.) were not significantly affected by sublethal toluene levels which caused behavioural disturbance. At 12.5 ppm of toluene (nominal concentration; ET50:69 h) ATP dropped gradually to less than 1% and E.C. to about 50% of the control values during 8 days, after which time all the individuals were dead. At 125 ppm neither ATP concentration nor E.C. changed significantly during 24 h although the animals were inactive after about 1 h and died within 100 h. Due to the high degree of stabilization of adenine nucleotide levels and E.C. during environmental changes, these parameters do not appear useful as general indices of stress in environmental pollution studies.  相似文献   

9.
Increased hazard of arsenic toxicity at many provinces of India causing extensive contamination of their wetlands. To illustrate the consequences of the arsenic menace on the aquatic fauna, a nutritionally important freshwater catfish Clarias batrachus (Linn.) was subjected to the stress of sublethal concentration (1 mg/L; 5% of 96‐h LC50 value) of sodium meta‐arsenite. The alterations induced by the arsenic salt on certain biomolecules (proteins, free amino acids (FAA), and protease activities) in five tissue components (muscle, liver, brain skin, and gills) of the fish using biochemical techniques were estimated. Significant (p < 0.01) decrease in the concentration of proteins in all the tissues (19.74–44.84% in muscles; 3.17–49.39% in liver; 10.05–36.16% in brain; 12.62–52.01% in skin and 7.34–61.69% in gills), and significant (p < 0.01) increase in FAA (6.84–269.89% in muscles; 125.89–358.03% in liver; 1.07–152.90% in brain; 29.31–401.62% in skin and 38.53–165.07% in gills), and protease activities (43.59–183.33% in muscles; 19.52–131.90% in liver; 8.85–46.72% in brain; 33.33–261.53% in skin and 25.39–50.79% in gills) of the exposed fish were observed. This increase in amino acids and enzyme activity point out toward breakdown of protein leading to their depletion.  相似文献   

10.
The LC50-value of diazinon for Brachydanio rerio decreases from 2.3 to 2.12 mg/1 during the time from 24 to 96 h. In the course of exposure for 24 to 288 h against 0.26 to 2.08 mg/1 diazinon the activity of acetylcholinesterase as well as acid and alkaline phosphatases decreases to 20.… 30% as a minimum. The decrease of the enzymatic activities in the brain tissue is more time-dependent than concentration-dependent, which may de due to the respective metabolites of diazinon.  相似文献   

11.
The present paper deals with the determination of LTm values of zolone, rogor, sumithion and abate for Channa gachua by conducting static bioassay experiments. The TLm values for zolone came out to be 0.08275 mg/l, 0.08225 mg/l, 0.0815 mg/l and 0.0810 mg/l; for rogor 5.155 mg/l; 4.955 mg/l, 4.65 mg/l and 4.475 mg/l; for sumithion 12.60 mg/l, 12.50 mg/l, 12.30 mg/l and 12.20 mg/l and for abate 217.25 mg/l, 225.575 mg/l, 221.575 mg/l and 217.25 mg/l for 24, 48, 72 and 96 hours, respectively. Relative susceptibility indicates that this fish is not susceptible to zolone and less to rogor, sumithion and abate, respectively. Present studies also show that increased temperature and pH increase the toxicity of all the biocides, but increased hardness of water decreases the toxicity of biocide solutions. The safe concentrations for zolone, rogor, sumithion and abate came out to be 0.02437 mg/l, 1.3733 mg/l, 3.6907 mg/l and 66.678 mg/l, respectively.  相似文献   

12.
The free amino acids of the liver and muscle of C. punctatus exposed to 1 ppm of copper sulphate solution up to 84 days were investigated. Few amino acids, notably cystine and tryptophan, disappeared and few new amino acids appeared. These changes in the free amino acids may be due to toxic effects of copper sulphate leading to rancidity in the fish.  相似文献   

13.
The effect of a sublethal concentration of malathion (95% E. C.) on the nucleic acids (DNA, RNA) and protein content in the liver of fingerlings of Channa punctatus, a freshwater murrel was investigated. 10 days of exposure brought non-significant alteration (P < 0.05) neither in the nucleic acids nor in protein content. However, significant quantitative decline in the liver's RNA (P < 0.01) and protein (P < 0.001) but not in the DNA content was observed after 20 days of exposure. Possible causes for such decline have been discussed.  相似文献   

14.
  • - In the present paper the toxicity of four biocides, endrin, thiodon, malathion and phosvel, has been measured by performing static bioassay experiments with Channa gachua as test fish to establish the median Tolerance Limits (TLm and TL50).
  • - The results of bioassay experiments indicate that the fish is harmed even at a very low concentration of these biocides. The values of TLm are 0.0076, 0.0073, 0.00695 and 0.0068 for endrin; 0.01120, 0.01088, 0.01069 and 0.01064 for thiodon; 9.20, 8.10, 7.90 and 7.60 for malathion and 32.90, 32.10, 31.65 and 31.15 mg/l for phosvel for the time interval of 24, 48, 76 and 96 hours, respectively.
  • - As indicated by TLm's, endrin is most toxic and phosvel least. Thiodon and malathion came in a descending order between endrin and phosvel.
  • - During bioassay studies, the effect of some variables, like temerature, pH and fish-size, on TLm's has also been observed. They gave the following results.
  • a) An increase in temperature increased the toxicity of all the biocides.
  • b) An increase in pH decreased the TLm as such, making the biocides more toxic to Channa gachua.
  • c) For larger fishes, the biocide solutions were less toxic, but the same solutions were more toxic to fishes of a smaller size.
  • - The safe harmless concentrations of endrin, thiodon, malathion and phosvel are - 0.00289 mg/l, 0.00337 mg/l, 1.88365 mg/l and 9.16736 mg/l, respectively.
  相似文献   

15.
The LC50 for 12… 96 h of a distillery waste water were determined for Lebistes reticulatus, Lymnaea luteola, Lymnaea acuminata and Viviparus bengalensis in the batch experiment with daily exchange of the medium. The sensitivity of the species increases in the given sequence with values of the LC50,96 h of 10.77 to 3.72 % proportion of wastewater in the medium. Compared with this, with values of the LC50,48 h of 14.06… 15.71 % after 48 h of exposure there is no significant difference in sensitivity, whereas after exposure for 12 and 24 h the sensitivity grows in the following order: V. bengalensis, L. acuminata, L. luteola, Lebistes reticulatus. Toxicity is obviously primarily determined by the sulphides; with increasing time of exposure also the suspended matter and other factors act toxically.  相似文献   

16.
Prolonged exposure to two pesticides Sevin and Thiodan for 30 days produced impairments in the brain of Channa striatus on the following ways:
  • – Separation and damage to meninges of cerebral hemispheres
  • – severe damage to all the five layers of the optic textum
  • – severe damage to torus longitudinalis
  • – partial damage to the molecular and grannular layers of the corpus cerebelli.
  • – no effect on diencephalon and myelencephalon.
  相似文献   

17.
Fish were kept in non-toxic water or at 0.5, 0.25 and 0.125 of the LC50,96h of the ten-side or insecticide for 24 h and fed with toxified and non-toxified feed. Toxified feed in normal water resulted in a maximum feed intake, while normal feed in toxified water resulted in a minimum one. In each case, the feed intake was lower compared with the control, and the feed intake was inversely proportional to the toxicant concentration. In a simple respirometer the oxygen consumption in mg · kg?1 · h?1 was tested for 1, 2, 4, 6, 8, 10, 12, 24, 36, 48, 60, 72, 84 and 96 h of exposure to 1.5, 1.0 and 0.5 of the LC50,96h of both substances. It was a flow device which was closed only for measurement for one hour. 1.5 LC50 Aldrin causes a continuous reduction of respiration until death. The same effect occurred with Cl. batrachus for 1.5 LC50 of the tenside, whereas with C. mrigala death was caused by a pronounced increase of respiration. In all other cases, after a phase of sensitization for 4 … 8 h respiration increased considerably to more than 300% of the control, which was followed after 12 … 24 h by acclimatization to normal respiration values.  相似文献   

18.
The toxicity of phenol, pentachlorophenol and Na-pentachlorophenate to Cypris subglobosa is determined in the batch experiment for 96. h. In the sequence mentioned, the LC50,96h of the three substances are 71.8, 6.56 and 4.41 mg/l, respectively. In the range of 6 … 95 h the mean survival time shows a negative regression to the toxicant concentration, which, however, is not significant statistically for Na-pentachlorophenate. In agreement with this, the LC50 for 12, 24, 48, 72 and 96 h of exposure shows a significant decrease. Due to the comparatively high LC50,96h for pentachlorophenol and Na-pentachlorophenate for C. subglobosa about in comparison with fish, the species is little suited to the toxicological investigation of wastewater.  相似文献   

19.
Urban populations are exposed to a high level of fine and ultrafine particles from motor vehicle emissions which affect human health. To assess the hourly variation of fine particle (PM2.5) concentration and the influence of temperature and relative humidity (RH) on the ambient air of Lucknow city, monitoring of PM2.5 along with temperature and RH was carried out at two residential locations, namely Vikas Nagar and Alambagh, during November 2005. The 24 h mean PM2.5 concentration at Alambagh was 131.74 μg/m3 and showed an increase of 13.74%, which was significantly higher (p < 0.05) than the Vikas Nagar level. The 24 h mean PM2.5 on weekdays for both locations was found to be 142.74 μg/m3 (an increase of 66.23%) which was significantly higher (p < 0.01) than the weekend value, indicating that vehicular pollution is one of the important sources of PM2.5. The mean PM2.5 at night for all the monitoring days was 157.69 μg/m3 and was significantly higher (p < 0.01) than the daytime concentration (89.87 μg/m3). Correlation and multiple regressions showed that the independent variables, i. e., time, temperature, and RH together accounted for 54%, whereas RH alone accounted for 53% of total variations of PM2.5, suggesting that RH is the best influencing variable to predict the PM2.5 concentration in the urban area of Lucknow city. The 24 h mean PM2.5 for all the monitoring days was found to be higher than the NAAQS recommended by the US‐EPA (65 μg/m3) and can be considered to be an alarming indicator of adverse health effects for city dwellers.  相似文献   

20.
Parthenium hysterophorus seed extract possesses the potentiality to alter the fish metabolism. Lower concentrations (sublethal) of the seed extract stimulate the respiratory muscles, resulting in an increased rate of O2 uptake, whereas higher concentrations (lethal) exhibit a neuro-toxic effect causing paralysis of the respiratory muscles manifested by a decreased rate of O2 uptake, cessation of the respiratory pumps and casualty by asphyxiation. The seed extract also inhibits the activity of the enzymes SDH and carbonic anhydrase at the gas exchange sites. The log/log plotting of the O2 uptake (mg/h) and the exposure period (2, 6, 12, 24, 72 and 168 h) showed slope values of 0.0744, 0.0778, 0.0322 and 0.0164, respectively, in four concentrations (10, 20, 25 and 30 %) of Parthenium extract.  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