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1.
The exposure of catfish, Heteropneustes fossilis to different concentrations (200, 500, 700, 1000, 1500, 2000 ppm) of crude oil extract for a varying period (for up to 48 h in lethal extract and 360 h in sublethal one) resulted into a number of haematological changes. All the parameters taken here were found to have been increased except the haemoglobin level which fell down to 14.3 % in an acute lethal concentration (2000 ppm) after 48 h of exposure. The haematocrit value increased significantly (12 %) in 2000 ppm. The blood sugar level showed hyperglycemia in all the concentrations. The increase in ascorbic acid (28 %) was pronounced in higher concentrations. Changes occurring in different parameters seemed to be reversible as all the parameters returned to their normal levels after returning the fish to normal media, except the nuclear swelling which did not resume the normal functioning even after a prolonged treatment (1 month or more) in the recovery jar. The haematological effects shown by the crude oil resembled partly those kept in severe hypoxic conditions and partly to the fishes poisoned by heavy metals (Cu and Zn). On the basis of results obtained in this investigation, crude oil may be categorised as a complex toxic agent.  相似文献   

2.
The sensitivity of respiratory mucus cells to the aqueous extracts of 200… 2000 ppm of crude oil has been determined in Puntius sophore using histochemical techniques. The results indicate the mucus cells to be highly susceptible to the crude oil poisoning in both lethal and sublethal concentrations. Sublethal extracts induce excessive mucus production and form a protective covering over branchial epithelia. Lethal extracts, however, reduce the number and size of the mucus cells causing scanty mucus secretion in short-term exposure (≦4 h), but degenerate the mucus cells when the exposure period is prolonged (≧12 h).  相似文献   

3.
Aqueous extracts of two petroleum oils, No. 2 fuel oil and Southern Louisiana crude, were tested on two amphipods, Gammarus muccronatus and Amphithoe valida, for survival. The oils were toxic at concentrations of 0.8 ppm (fuel oil) and 2.4 ppm (S. Louisiana crude). Mortalities increased with the concentration and length of exposure. Few or no young were produced at these and higher concentrations (breeding adults were decreasing rapidly in numbers). The amphipods are more sensitive to aqueous extracts of these oils than benthic polychaetes and shrimp, for which data are available.  相似文献   

4.
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   

5.
A biotest system for environmentally realistic exposure of fish to produced water (PW) was developed and tested. Authentic PW was collected at an oil production platform in the North Sea and preserved by freezing in multiple aliquots a 25 L. After transport to the test laboratory onshore, daily PW aliquots were thawed, homogenised and administered to the test fish, Atlantic cod (Gadus morhua), in two diluted exposure concentrations, 0.1% and 0.5%, during a 15 d period, using a continuous flow-through exposure setup. Positive control groups were exposed to two crude oil treatments for comparison. Chemical analyses showed that alkylphenol (AP) and PAH concentrations in PW exposure waters were very low. Observations of significantly increased AP and PAH metabolite levels in PW exposed fish demonstrated the suitability of the biotest system for its use in biological exposure/effect studies of PW, and it also demonstrated the sensitivity of bile metabolites as PW exposure markers in fish. The relevance of the biotest system for PW effect studies and for validating modelled environmental risk estimates of PW dischargers from offshore oil production is discussed.  相似文献   

6.
The tolerance level of the fertilizer NPK for the freshwater siluroid Mystus M. vittatus (BL .) and histopathological changes in the gill of this fish against two concentrations of NPK were investigated. It was found that at 400 ppm (24 h) mortality in the fish started, and at 700 ppm (96 h) all the fish died. Hence the concentration of NPK at 400 ppm was taken as an experimental concentration for this fish. Curling towards the upperside in the secondary lamellae resulting in the joining with each other and profuse mucus secretion and subsequent death of 40% of the fish (96 h) were observed. At 700 ppm (96 h) NPK, which is far higher than the highest tolerance limit of the fish, all the fish died. Profuse mucus secretion, formation of subepithelial spaces, sloughing of epithelial layer, leaving only the rows of pilaster cells, resulting in the death of the fish, were observed. The mortality of the fish was due to asphyxiation and damage in the gill tissues resulting in the alteration in the respiratory and osmoregulatory metabolism.  相似文献   

7.
The effects of chronic exposures to sublethal concentration of two pesticides Carbaryl and Endosulfan on alkaline and acid phosphatase activities in the intestine of a fresh water teleost Channa striatus have been observed by exposing the fish for a period of two to thirty days to 10 ppm and 20 ppm of Carbaryl and 0.00075 and 0.001 ppm of Endosulfan. The inhibition of alkaline phosphatase activity has been dependent on the duration of exposure, concentration and the type of pesticide used. The acid phosphatase activity increased with the duration of exposure in higher concentration of Carbaryl and both the concentrations of Endosulfan. Endosulfan produced more pronounced effects than Carbaryl.  相似文献   

8.
The toxicity of distillery wastes to the fish Rasbora daniconius was tested by bioassay. Ten concentrations ranging from 1.0 to 100% were employed. It was found that the fish were quite tolerant at the 1% concentration for about 24 hours of exposure and survived even up to 96 hours. Mortality was noticed in concentrations from 1.5% onwards. In the concentrations of 3.0% and above there was a heavy mortality beginning at 15 hours of exposure. From the chemistry of the medium studied it was found that the toxicity was inversely proportional to pH but directly proportional to conductivity and bicarbonate alkalinity of the medium.  相似文献   

9.
Freshwater fish Cyprinus carpio have been exposed to sublethal concentrations of fenvalerate (0.010 ppm) and cypermethrin (0.020 ppm) for 6, 12, 24 and 48 hours. After each exposure period, certain blood parameters were studied. A decrease in red blood corpuscular (RBC) count, haemoglobin (Hb) concentration, packed cell volume (PCV) and mean corpuscular haemoglobin concentration (MCHC), on the one hand, and an increase in mean corpuscular volume (MCV) and mean corpuscular haemoglobin (MCH), on the other hand, have been observed with increasing time of exposure. The alterations observed may be due to the physiological disfunctioning of the haemopoietic tissue or may be due to the effect on the bone marrow. The effect of fenvalerate is more pronounced than that of cypermethrin.  相似文献   

10.
Embryos and juveniles of the sheepshead minnow (Cyprinodon variegatus), a saltwater fish, were exposed to ammonium jarosite, a waste product of the processing of zinc ore, during a 28-day posthatch, flow-through toxicity test. Exposure to measured ammonium jarosite concentrations ≤ 290 ppm had no significant effect on the hatching success of embryos. However, slight delays in hatching were observed in test concentrations ≥ 140 ppm. Although exposure to test concentrations ≥ 140 ppm significantly decreased the ability of juvenile fish to uncurl after hatching, juvenile mortality was significantly increased only in test concentrations ≥ 230 ppm. There was no effect on growth of juvenile fish in jarosite concentrations ≤ 230 ppm. The estimated maximum acceptable toxicant concentration (MATC), based on measured concentrations, was > 140< 230 ppm.  相似文献   

11.
The effect of crude oil on the histochemical localization of branchial enzymes CA, SDH, LDH, Alkpase and Acidpase was investigated in Colisa fasciatus. The activity of all the enzymes experimented here was found to have decreased when treated with the lethal solutions of crude oil except the LDH which showed an increasing trend throughout the experiment. A transitory increase in the CA and SDH was observed in the beginning but reached an almost normal level after 48 h in 1000 ppm. On the basis of sensitiveness towards crude oil toxicity, the enzymes have been arranged in the following order: LDH > SDH > CA > Alkpase > Acidpase. The results suggest that crude oil is capable of impairing the enzyme activity. The decreased or increased level of enzymes may be used as an indicator for assessing the toxicity of oil pollutants.  相似文献   

12.
The toxic effects of crude oil, the dispersant, Corexit 7664, and mixtures of these on the respiration and mortality of two species of bivalve have been examined. A light Arabian crude is most toxic to one, Corexit is most toxic to the other. The susceptibility to oil of the mussel Brachidontes is also reflected in a significant depression of respiration rate at sub-lethal concentrations.  相似文献   

13.
Residues of DDT isomers accumulated in the testes of Channa punctatus (BLOCH) were quantitatively estimated by exposing the fish to 2.5 ppm sublethal concentration for 32 days. The study revealed a high accumulation of DDT residues in the testes. The maximum concentration of residues was noted on the 32nd day of the experiment. The DDT isomer accumulated in maximum concentrations was followed by DDE and DDD isomers. The maximum residue concentrations were 0.3221 ppm (DDT), 0.1119 ppm (DDE) and 0.0695 ppm (DDD) on the 32nd day of the experiment. The total DDT residue concentration at the final interval was 0.563 ppm.  相似文献   

14.
Mytilus edulis and Chlamys islandica were exposed to nominal dispersed crude oil concentrations in the range 0.015–0.25 mg/l for one month. Five biomarkers (enzymatic and cellular responses) were analysed together with bioaccumulation of PAHs at the end of exposure. In both species, PAH tissue residues reflected the exposure concentration measured in the water and lipophylicity determined the bioaccumulation levels. Oil caused biomarker responses in both species but more significant alterations in exposed C. islandica were observed. The relationships between exposure levels and enzymatic responses were apparently complex. The integrated biomarker response related against the exposure levels was U-shaped in both species and no correlation with total PAH body burden was found. For the monitoring of chronic offshore discharges, dose- and time-related events should be evaluated in the selection of biomarkers to apply. From this study, cellular damages appear more fitted than enzymatic responses, transient and more complex to interpret.  相似文献   

15.
Studies have been made of the effects of exposure to various forms of crude oil on the righting behaviour of Paracentrotus lividus and its reactions towards the presence of oil. Prolongation of the righting response was recorded in animals exposed to contact with surface or sunken fresh crude oil or to their water soluble fractions. No such effect was recorded on exposure to weathered oils and results indicate that the more volatile components of crude oil were responsible for this effect. Paracentrotus showed no avoidance reaction to the presence of sunken oil in its vicinity. The likely ecological significance of these results is discussed.  相似文献   

16.
Emulsions of crude oil are lethal to larvae of the American Iobster at concentrations of 100 ppm and appear to have sublethal effects at concentrations down to 1 ppm.  相似文献   

17.
The 96h LC50 of the water soluble fraction (WSF) of natural gas condensate from the Sable Is., N.S. area to Fundulus heteroclitus was between 4 and 5 μg · ml−1 naphthalene equivalents (initial concentration). Behavioural responses in the fish to sub-lethal concentrations of WSF were similar to those recorded for crude and fuel oils. Induction of the hepatic mixed function oxidase enzyme enthoxyresorufin O-de-ethylase (EROD) in sexually immature fish occurred at WSF concentrations below the LC50, but during the prespawning period no induction occurred. EROD activity in unexposed fish showed seasonal variation consistent with differences in its inducibility.  相似文献   

18.
Most crude oils spread on open water to an average thickness as low as 0.1 mm. The application of dispersants enhances the transport of oil as small droplets into the water column, and when combined with the turbulence of 1 m waves will quickly entrain oil into the top 1 m of the water column, where it rapidly dilutes to concentrations less than 100 ppm. In less than 24 h, the dispersed oil is expected to mix into the top 10 m of the water column and be diluted to concentrations well below 10 ppm, with dilution continuing as time proceeds. Over the multiple weeks that biodegradation takes place, dispersed oil concentrations are expected to be below 1 ppm. Measurements from spills and wave basin studies support these calculations. Published laboratory studies focused on the quantification of contaminant biodegradation rates have used concentrations orders of magnitude greater than this, as it was necessary to ensure the concentrations of hydrocarbons and other chemicals were higher than the detection limits of chemical analysis. However, current analytical methods can quantify individual alkanes and PAHs (and their alkyl homologues) at ppb and ppm levels. To simulate marine biodegradation of dispersed oil at dilute concentrations commonly encountered in the field, laboratory studies should be conducted at similarly low hydrocarbon concentrations.  相似文献   

19.
Laboratory acclimated Labeo rohita, common fresh water edible fish, were exposed to a sublethal concentration (2.5 ppm) of DDT for 2, 4, 8, 16 and 32 days. Residues of three isomers of DDT were estimated in the kidney of Labeo rohita using the gas liquid chromatographic technique. The maximum residues of DDT, DDE and DDD were 1.4327, 0.4172 and 0.2913 ppm, respectively. The total DDT residues concentration was 2.1412 ppm on the final day of the experiment. The tabulated tcalculated t at all intervals.  相似文献   

20.
A preliminary study was undertaken to determine the optimal conditions for the biodegradation of a crude oil. Among 57 oil‐degrading bacterial cultures isolated from oil‐contaminated soil samples, Bacillus sp. IOS1‐7, Corynebacterium sp. BPS2‐6, Pseudomonas sp. HPS2‐5, and Pseudomonas sp. BPS1‐8 were selected for the study based on the efficiency of crude oil utilization. Along with the selected individual strains, a mixed bacterial consortium prepared using the above strains was also used for degradation studies. The mixed bacterial consortium showed more growth and degradation than did individual strains. At 1% crude oil concentration, the mixed bacterial consortium degraded a maximum of 77% of the crude oil. This was followed by 69% by Pseudomonas sp. BPS1‐8, 64% by Bacillus sp. IOS1‐7, 45% by Pseudomonas sp. HPS2‐5, and 41% by Corynebacterium sp. BPS2‐6. The percentage of degradation by the mixed bacterial consortium decreased from 77 to 45% as the concentration of crude oil was increased from 1 to 12%. Temperature of 35°C and pH 7 were found to be optimum for maximum degradation.  相似文献   

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