Alteration in some biochemical and enzymological parameters in the snake head fish , exposed chronically to quinalphos

The effect of chronic quinalphos exposure (0.025 mg/1) for 15 and 30 days on the levels of glucose, lactic acid and haemoglobin in the blood; glycogen and lactic acid contents of the liver and muscles; and the activities of hexokinase, lactate dehydrogenase, pyruvate dehydrogenase and succinate dehydrogenase in liver, kidney, intestine, brain, gills and muscles was examined. Blood glucose, lactic acid and haemoglobin levels decreased in quinalphos exposed fish. Glycogen content of liver and muscles increased but lactic acid decreased. Hexokinase was inhibited in intestine and muscles after 30 days of exposure but increase in enzyme activity was noted in gills. Lactate dehydrogenase activity was inhibited in all the six tissues. Pyruvate dehydrogenase activity of liver, kidney, gills and muscles was inhibited. However, in brain the enzyme activity was elevated. Succinate dehydrogenase activity was elevated in intestine and inhibited in other tissues.     

Alteration in some biochemical and enzymological parameters in the snake head fish Channapunctatus, exposed chronically to quinalphos

The effect of chronic quinalphos exposure (0.025 mg/1) for 15 and 30 days on the levels of glucose, lactic acid and haemoglobin in the blood; glycogen and lactic acid contents of the liver and muscles; and the activities of hexokinase, lactate dehydrogenase, pyruvate dehydrogenase and succinate dehydrogenase in liver, kidney, intestine, brain, gills and muscles was examined. Blood glucose, lactic acid and haemoglobin levels decreased in quinalphos exposed fish. Glycogen content of liver and muscles increased but lactic acid decreased. Hexokinase was inhibited in intestine and muscles after 30 days of exposure but increase in enzyme activity was noted in gills. Lactate dehydrogenase activity was inhibited in all the six tissues. Pyruvate dehydrogenase activity of liver, kidney, gills and muscles was inhibited. However, in brain the enzyme activity was elevated. Succinate dehydrogenase activity was elevated in intestine and inhibited in other tissues.     

Chronic effects of mercuric chloride on the activities of some enzymes in certain tissues of the fresh water murrel,

Alterations in the activities of some enzymes in the brain, gills, intestine, kidney, liver and muscles have been examined in the fresh water murrel, , after exposure to a sublethal concentration of mercuric chloride (3 μg/1) for 15, 30 and 60 days. The results revealed that after 15 days of exposure amino acid oxidase activity was elevated in brain and liver and inhibited in intestine. The activity of xanthine oxidase was increased in gills, and inhibited in kidney. Thirty days exposure produced significant inhibition in the activities of malate dehydrogenase in liver, glutamate dehydrogenase in gills and brain, aminoacid oxidase in gills, and xanthine oxidase in liver and intestine. In contrast, glutamate dehydrogenase in intestine, kidney and liver and aminoacid oxidase in brain and liver were elevated. After 60 days of treatment, a decrease in the activity of glucose-6-phosphatase was recorded in gills, intestine, kidney and liver. Hexokinase activity in kidney and liver, and malate dehydrogenase in all the six tissues were inhibited. Glutamate dehydrogenase activity in intestine, kidney and liver remained higher than in control fish. In brain, kidney and liver the activity of aminoacid oxidase was elevated, but in gills the enzyme activity decreased. Xanthine oxidase activity was inhibited in intestine and liver.     

Chronic effects of mercuric chloride on the activities of some enzymes in certain tissues of the fresh water murrel, Channapunctatus

Alterations in the activities of some enzymes in the brain, gills, intestine, kidney, liver and muscles have been examined in the fresh water murrel, $\text{Channa}$$\text{punctatus}$, after exposure to a sublethal concentration of mercuric chloride (3 μg/1) for 15, 30 and 60 days. The results revealed that after 15 days of exposure amino acid oxidase activity was elevated in brain and liver and inhibited in intestine. The activity of xanthine oxidase was increased in gills, and inhibited in kidney. Thirty days exposure produced significant inhibition in the activities of malate dehydrogenase in liver, glutamate dehydrogenase in gills and brain, aminoacid oxidase in gills, and xanthine oxidase in liver and intestine. In contrast, glutamate dehydrogenase in intestine, kidney and liver and aminoacid oxidase in brain and liver were elevated. After 60 days of treatment, a decrease in the activity of glucose-6-phosphatase was recorded in gills, intestine, kidney and liver. Hexokinase activity in kidney and liver, and malate dehydrogenase in all the six tissues were inhibited. Glutamate dehydrogenase activity in intestine, kidney and liver remained higher than in control fish. In brain, kidney and liver the activity of aminoacid oxidase was elevated, but in gills the enzyme activity decreased. Xanthine oxidase activity was inhibited in intestine and liver.     

Analysis of copper,zinc, cadmium and chromium in fish tissues. A tool for detecting metal caused fish kills

In order to find the causative agent in frequently occuring fish kills in a Belgian river a series of toxicity tests has been conducted in which rudd (Scardinius erythrophtalmus) were exposed to acute lethal and subacute non lethal concentrations of copper, chromium, cadmium and zinc. The concentrations of these metals in gills, opercle, kidney, liver and muscle were measured. Metal levels in gills were the most valuable indicator of acute lethal exposure. This information was compared with levels found in rudd from a surface water storage reservoir and from the river Meuse. Fish collected after fish kills in the river Meuse were analysed. In one case copper could be identified as one of the toxicants concerned by fish tissue analysis. Metal levels in fish tissues can give valuable additional information concerning the cause of kills provided that background information is available about metal levels in water and normal tissue levels.     

Comparative study of different exposure routes on the biotransformation and genotoxicity of PAHs in the flatfish species, Scophthalmus maximus

In this study, laboratory experiments were carried out in order to come to a better understanding of the fate of polycyclic aromatic hydrocarbons (PAHs) in the marine environment and especially on their bioaccumulation, biotransformation and genotoxic effects in fish. Juveniles of turbot (Scophthalmus maximus) were exposed to PAHs through different routes via (1) a mixture of dissolved PAHs, (2) a PAH-polluted sediment and (3) an oil fuel elutriate. Fish were exposed 4 days followed by a 6-day depuration period. In each experiment, PAH concentrations in the seawater of the tanks were analysed regularly by gas chromatography coupled with mass spectrometry. Muscle and liver samples were also analysed for parent PAH levels and PAH bioconcentration factors were calculated. Biotransformation was evaluated by measuring the levels of PAH metabolites in fish bile. Genotoxicity was assessed by the alkaline comet assay. Regardless of exposure route, the parent PAH concentrations in the liver and muscle showed a peak level 1 day after the beginning of the exposure, followed by a decrease up to the background level towards the end of the experiment, except for the exposure to dissolved PAHs for which levels were relatively low throughout the study. As a consequence, no bioaccumulation was observed in fish tissues at the end of the experiment. In contrast, regardless of exposure routes, a rapid production of biliary metabolites was observed throughout the whole exposure experiment. This was especially true for 1-hydroxypyrene, the major metabolite of pyrene. After 6 days of recovery in clean water, a significant decrease in the total metabolite concentrations occurred in bile. Fish exposed through either route displayed a significant increase in DNA strand breaks after 4 days of exposure, and significant correlations were observed between the level of biliary PAH metabolites and the level of DNA lesions in fish erythrocytes. Overall results indicate that exposure to either a mixture of dissolved PAHs, a PAH-contaminated sediment or a dispersed oil fuel elutriate leads to biotransformation and increase in DNA damage in fish. The quantification of PAH metabolites in bile and DNA damage in erythrocytes appear to be suitable for environmental monitoring of marine pollution either in the case of accidental oil spills or sediment contamination.     

Assessment of copper and zinc levels in fish from freshwater ecosystems of Moldova

Purpose

The aim of this work was to assess the levels of copper and zinc in fish from the main freshwater ecosystems of Moldova, in relation with species, habitat, age, sex, season, and development stage.

Methods

Fish from Cyprinidae and Percidae families (Cyprinus carpio, Carassius auratus gibelio, Rutilus rutilus heckeli, Abramis brama, Aristichthys nobilis, Hypophtalmichthys molitrix, Sander lucioperca) were collected from Prut and Dniester rivers, Cuciurgan, Dubasari, and Costesti-Stanca reservoirs, and ponds of farms in the Dniester delta. The Cu and Zn content of fish tissues (skeletal muscles, liver, gonads, gills, skin, and scales) was determined by flame atomic absorption spectrophotometer AAS-3, of water by graphite furnace HGA 900 of AAnalist 400.

Results

The level of heavy metals accumulation in muscles of immature fish follows their dynamics in water. The highest concentration of zinc was registered in the gonads of mature fish, and of copper??in the liver. The lowest Cu and Zn contents were recorded in the muscles and are in the United Nations Food and Agriculture Organization safety-permissible levels for human consumption. Cu and Zn contents in muscles of fish depend on specimen age. Their level in fish gonads was sharply increasing during pre-spawning period. During the early developmental stages, the metal concentration in fish eggs and larvae varies within wide limits, but the accumulation pattern is similar in the investigated species.

Conclusions

The fish represent one of the most indicative factors for the estimation of trace metals pollution in freshwater systems and this is important not only for monitoring purposes, but also for the fish culture ones.     

Cypermethrin induced alterations in nitrogen metabolism in freshwater fishes

In the present study, two fresh water fishes namely, Channa punctatus and Clarias batrachus, were exposed to three sub-acute concentrations of synthetic pyrethroid, cypermethrin, for 96 h to evaluate the role of amino acids in fulfilling the immediate energy needs of fishes under pyrethroid induced stress as well as to find out the mechanism of ammonia detoxification. The experiments were designed to estimate the levels of free amino acid, urea, ammonia and the activities of aspartate aminotransferase (AAT), alanine aminotransferase (AlAT), glutamate dehydrogenase (GDH), glutamine synthetase (GS) and arginase in some of the vital organs like brain, gills, liver, kidney and muscle of both fish species. The significant decrease in the levels of amino acids concomitant with remarkable increase in the activities of AAT, AlAT and GDH in these vital tissues of fish species elucidated the amino acid catabolism as one of the main mechanism of meeting out the immediate energy demand of the fishes in condition of cypermethrin exposure. The levels of ammonia were significantly increased at 10% of 96 h LC(50) of cypermethrin in the different organs such as brain, gills, liver, kidney and muscle of both fish species while 15% and 20% concentrations of 96 h LC(50) of cypermehrin registered remarkable decline in both fish species. The differential increment in the activities of GDH, GS and arginase and in the level of urea established three different alternative mechanisms of ammonia detoxification. The results indicated that in C. punctatus, the prevalent mode of nitrogen excretion is in the form of conversion of ammonia into glutamine and glutamate while in C. batrachus, the excessive nitrogen is excreted in the form of urea synthesized from ammonia.     

Toxicity of lindane (γ-hexachloroxiclohexane) in Sparus aurata,Crassostrea angulata and Scrobicularia plana

The purpose of the present study was to research the sublethal and/or lethal effects produced by the exposure of fish and shellfish to the γ isomer of lindane, γ-hexachlorocyclohexane (γ-HCH). The teleostean fish Sparus aurata and the shellfish Crassostrea angulata and Scrobicularia plana, were exposed to 16 μ g/L of lindane for 15 days. Samples of different fish (liver, kidney and gills) and shellfish (gills, gut, digestive gland and mantle) tissues were extracted and processed for histopathological observations. Although mortality was not detected during the bioassay, sublethal effects (histopathological alterations) were observed. Vacuolization in the liver cells and lamellar fusion in gills from exposed fish were observed. Disorganization of normal gill structure, epithelial desquamation with the disappearance of apical ciliature in intestine, and inflammatory response in mantle from exposed shellfish were also observed. Thus, it can be concluded that the lindane concentration employed in the present research did not produce lethal effects in the exposed organisms but it caused sublethal effects. Lindane has time-dependent multiple toxic effects in S. aurata, C. angulata and S. plana, which were more severe at the end of the experimental time. The toxicological implications arising from these results are subjects for further multiconcentration tests dealing with lethal responses (mortality) or with sublethal responses (cellular/molecular biomarkers) of the aforementioned species.     

Uptake and accumulation of mercury from dental amalgam in the common goldfish,Carassius auratus

In this study, the bioavailability and accumulation of mercury from external environmental exposure to mixed, cured, milled, sieved and proportioned dental amalgam was examined in the common goldfish, Carassius auratus. Fish were exposed to dental amalgam (particle size range from < 0.10 to 3.15 mm) in order to represent the particle size and distribution of that found within the typical dental office wastewater discharge stream. Experimental amalgam water loadings were 0 g/l, 0.5 g/l and 1 g/l in glass aquaria at 15 degrees C for 28 days. Fish tissues were sampled at 5 min and 28 days of exposure, and the liver, brain, muscle and whole body analyzed for total mercury using cold vapor atomic fluorescence spectroscopy. Mercury was found in several tissues examined and generally increased with exposure to higher amounts of dental amalgam. The highest levels were found in the whole body (17.68 +/- 5.73 microg/g) followed by the liver (0.80 +/- 0.16 microg/g) and muscle (0.47 +/- 0.16 microg/g). The lowest concentrations were seen in the brain (0.28 +/- 0.19 microg/g). Compared to controls, concentrations in the whole body, muscle and liver in fish exposed for 28 days to the highest concentration of amalgam were 200-, 233-, and 40-fold higher, respectively. This study shows that mercury from an environmental exposure to representative samples of dental amalgam typically found within the dental wastewater discharge stream is bioavailable to fish and may accumulate in internal tissues.     

Transport and fate of dieldrin in poplar and willow trees analyzed by SPME

Dieldrin is a hydrophobic organochlorine insecticide that is persistent in the environment. The fate and transport of dieldrin in trees is important both in the context of potential remediation, as well as food chain impacts through dieldrin transport to shoots and leaves. Experiments were conducted to measure the degree of dieldrin partitioning to plant tissue and the potential for biodegradation of dieldrin in the microbe rich tree rhizosphere. Dieldrin was analyzed in water and plant tissue using headspace solid-phase microextraction (SPME) coupled with gas chromatography. Poplar and willow saplings planted in soil and watered with 10 microgl(-1) dieldrin for up to 9 months showed no adverse effects due to dieldrin exposure and no dieldrin was observed in plant shoots with a method detection limit (MDL) of 7 ngg(-1). One-week hydroponic tests of poplar saplings exposed to aqueous dieldrin also showed no detection of dieldrin in shoots, with an average of 66% of the dieldrin partitioned to the plant roots and an overall mass balance recovery of 76% in the plant-water system. The root concentration factor (RCF) was found to be 30+/-3 ml water g(-1) root. Biodegradation of dieldrin was not observed in an aqueous batch bioreactor containing 8 microgl(-1) dieldrin, nutrients and bacteria from the root zone of a poplar sapling that had been exposed to dieldrin for 9 months. These results show that planting trees is likely to be safe and potentially useful at sites containing low-levels of dieldrin in groundwater.     

Uptake, tissue distribution and metabolism of the insecticide endosulfan in Jenynsia multidentata (Anablepidae, Cyprinodontiformes)

The study reports the accumulation, distribution and metabolism of technical endosulfan in Jenynsia multidentata. Adult females were exposed to acute sublethal concentrations (0.072, 0.288 and 1.4 μg L⁻¹). After 24 h, fish were sacrificed and gills, liver, brain, intestine and muscle were removed. Results show that both isomers of technical-grade endosulfan (α- and β-) are accumulated in fish tissues and biotransformation to endosulfan sulfate occurs at all concentrations tested. Significantly differences in endosulfan accumulation were only found at 1.4 μg L⁻¹ but not between the lowest concentrations. However a similar distribution pattern was observed at all exposure levels where liver, intestine and brain had the highest levels of α-, β-endosulfan and endosulfan sulfate. Moreover, liver and brain showed the highest endosulfan sulfate:α-endosulfan ratios due to high biotransfomation capacity. J. multidentata demonstrated to be a sensitive species under exposure to technical endosulfan and, therefore, could be used to assess aquatic pollution.     

Residues of organochlorine pesticides in environmental samples from the Shatt al-Arab River, Iraq

Application of high resolution gas chromatography has confirmed relatively low residue levels of sumDDT, endrin and dieldrin in the Shatt al-Arab River. Thus, average concentration of these compounds in the edible portion of the cyprinid (Barbus xanthopetrus) were 21, 4 and 2 microg kg(-1) wet weight respectively. Mean values of sumDDT, endrin and dieldrin in surface sediments were 5, 40 and 20 microg kg(-1) dry weight respectively. Shrimps sampled from the Shatt al-Arab River were found to contain residues of o, p'-DDD only (average concentration was 2 microg kg(-1) wet weight). However, comparison of these samples with those from an area affected directly by a point source of organochlorine pesticides has shown that the cyprinid of the same age group contained significantly higher residue levels (average concentrations of sumDDT, endrin and dieldrin were 166, 20 and 7 microg kg(-1) wet weight respectively). Thus, it may be concluded that there was no direct input of organochlorine pesticides to the Shatt al-Arab River, and transportation via the natural processes, such as drainage, appeared to be the sole source. Based upon the observation that the original compound (p,p'-DDT) has not been detected in this river, it has also been concluded that there was no recent contribution of DDT here. Relatively higher residue levels of sumDDT, endrin and dieldrin were encountered in the muscles of the Indian shad captured from the Shatt al-Arab River (average concentrations were 163, 80 and 28 microg kg(-1) wet weight respectively). However, these elevated values were attributed to this fish being migratory and it being exposed to these pesticides elsewhere.     

Metal accumulation in the smooth toadfish, Tetractenos glaber, in estuaries around Sydney, Australia

This study determined the metal levels in sediments and tissues of a common estuarine fish, Tetractenos glaber (smooth toadfish), from two metal contaminated and two reference estuaries near Sydney, Australia. Metal levels were highest in sediments and fish from contaminated estuaries. Gonads contained the highest metal levels followed by muscle, gill and liver. Metal accumulation was gender-dependant (e.g. male gonads were >20 times higher in As than females; female gills were >30 times higher than males for Pb). Cadmium, Pb and Ni levels in fish tissues reflected sediment levels, indicating sediment and/or dietary metal uptake. Levels of As, Co, Cd & Pb in gills showed similar patterns to other tissues, suggesting that metals may have been taken up by gills through contaminated water. Similar metal patterns in tissues and sediments suggest more than one uptake pathway. This study indicates that multiple factors influence metal accumulation in fish.     

Uptake from water, release and tissue distribution of 54Mn in the Rainbow trout (Oncorhynchus mikiss Walbaum)

As part of a research programme on the transfer of several radionuclides along a pelagic trophic chain, two groups of 12 trout were kept for 8 weeks in water contaminated with 30 Bq ml(-1) of (54)Mn. In order to simulate chronic contamination and limit alterations in the physical and chemical characteristics of the medium, the water was renewed every 2 days. The kinetics of the accumulation and elimination of the radionuclide were monitored in one group of fish. The second group was used to study the contamination of the main organs and tissues at the end of the accumulation phase. The dynamics of contamination can be described by a bi-compartmental model, taking into account the fluctuations in the concentration of (54)Mn in the water, as well as the biological dilution resulting from the growth of the fish. The theoretical value of the steady-state concentration factor for zero growth is 13 (w.w.) and the radionuclide release is characterised by two biological half-lives of 6 and 97 days. At the end of the accumulation phase, the (54)Mn is preferentially fixed in the bone, gills, skin and brain. The data obtained at the end of the depuration phase allow one to classify the organs in two groups with different elimination kinetics. The first group consists of organs of penetration or transit, such as the skin, gills, kidneys, liver, primary and secondary gut and viscera, whereas the second group is made up of the receptor and storage organs and tissues such as the bone, head, fins and muscle.     

Stable isotope determination in wild and farmed gilthead sea bream (Sparus aurata) tissues from the western Mediterranean

Stable isotopes of carbon and nitrogen (delta(13)C and delta(15)N) have been determined in wild and farmed gilthead sea bream (Sparus aurata) samples of white and red muscle, liver, gills and gonads. First, delta(13)C and delta(15)N values were determined in samples with and without lipid removal to check the possible effect of lipid content on the stable isotope values of the different tissues studied. Differences were found for delta(13)C in all tissues studied apart from white muscle of wild fish, the tissue with the lowest lipid content. For delta(15)N values no differences were found in wild fish tissues. Liver from farmed fish showed lower delta(15)N value after lipid removing. Further conclusions were based on results obtained from lipid-free samples. delta(13)C of cultured fish tissues showed a mean depletion of 2.9+/-0.4 per thousand compared to wild specimens, suggesting different sources of carbon in the diet, probably due to the feed used during sea-cage culture. Cultured gilthead sea bream tissues were significantly more enriched in nitrogen than wild specimens by an average of 1.5+/-0.2 per thousand in white muscle, indicating a slight increase in the trophic level. Determination of stable isotope signatures of gilthead sea bream tissues allows clear discrimination between wild and cultured sea bream, and characterisation of differences in diet and feeding conditions in any tissue studied.     

Multiple biomarkers of pollution effects in Solea solea fish on the Tunisia coastline

This field study investigates the morphological indices (condition index, hepatosomatic index) and biochemical (catalase (CAT), glutathione S-transferase (GST), acetylcholinesterase (AChE), metallothionein (MT), lipid peroxidation) parameters in liver, gills and kidney of common sole (Solea solea) originating from different sites of the Tunisian coast area impacted by different anthropogenic activities. Differences among sites and tissues for AChE, GST, CAT, MT and TBARS were found and possibly related to known sources of domestic and industrial discharges in the studied sites. Liver, gills and kidney CAT, liver and kidney MT and brain AChE were key biomarkers to discriminate fish of different sites. So, we suggest using these biomarkers in future biomonitoring.     

Heavy metal accumulation in edible fish species from Rawal Lake Reservoir, Pakistan

The aim of the present study was to describe the accumulation of trace metals in the liver, kidney, gills, muscles, and skin of four edible fish species (Tor putitora, Cirrhinus mrigala, Labeo calbasu, and Channa punctatus) of Rawal Lake Reservoir, Pakistan. The fish samples were collected in the pre-monsoon (May 2008) and post-monsoon (October 2007) seasons and were analyzed for heavy metals by using an atomic absorption spectrometer. Kidney and liver showed relatively high concentrations of heavy metals. The accumulation of metals in the different organs of the fish (skin, muscles, and gills) in post-monsoon was higher than in pre-monsoon. In pre-monsoon, the metals followed the trend Zn > Pb > Fe > Cr > Ni > Mn > Co > Cu > Cd > Li, while in the post-monsoon season, the trend was Fe > Pb > Cr > Ni > Zn > Cu > Co > Mn > Cd > Li. The concentrations of Ni, Cr, and Pb in the muscle of all fish species were higher than the WHO guideline values of heavy metals in fishes for human consumption except in T. putitora. Cu level was nearly equal to the WHO maximum levels in C. mrigala and L. calbasu, while it was lower in T. putitora and C. punctatus. It is strongly advocated that risk assessment studies should be conducted and there is an urgent need for water quality restoration and management of Rawal Lake Reservoir.     

Photoprotective substance occurs primarily in outer layers of fish skin

Methanol extracts of dorsal skin layers, eyes, gills, and livers from ultraviolet-B (UVB) radiation-sensitive and UVB-tolerant species of freshwater fish were examined for a substance that appears to be photoprotective. Significantly larger amounts of this substance were found in extracts of outer dorsal skin layers from both UVB-sensitive and UVB-tolerant fish when compared with extracts of inner dorsal skin layers. This substance occurred in minor amounts or was not detected in eye, gill, and liver extracts. The apparent primary function of this substance in fish is to protect the cells in outer dorsal skin layers from harmful levels of UVB radiation.