Adverse effects of chromium on amino acid levels in freshwater fish Clarias batrachus (Linn.)

Various heavy metals released into the rivers and lakes affect aquatic fauna including Clarias batrachus. Elevated levels of chromium (Cr) in aquatic organisms, especially fish, represent an ecological and human concern. Amino acid levels were estimated in five tissues (gills, liver, kidneys, muscle, and brain) of C. batrachus after 28 days of exposure to Cr. This study showed that Cr elevated levels of free amino acids in organs of fish C. batrachus, indicating a compensatory mechanism to counter sublethal metallic stress. Data suggest that the measurement of amino acids may serve as a biomarker for Cr toxicity in fish.     

Biomarkers of oxidative stress as indicators of water pollution in Nile tilapia (Oreochromis niloticus) from a water reservoir in Riyadh,Saudi Arabia

Antioxidant enzyme activities of fish (Oreochromis niloticus) were determined in order to assess the status of pollution in the Wadi Namar (WN), near Riyadh, Saudi Arabia. Activities of four antioxidant enzymes as superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), and concentrations of glutathione (GSH) and oxidant malondialdehyde (MDA) were selected as bioindicators. Fish (n = 14) were sampled in the month of April 2013 from WN and a control site (CS). SOD activity was increased by 37.9%, 47%, and 29% in kidney, liver, and heart, respectively, while a significant decrease (36.4%) was observed in gills of O. niloticus from WN as compared to fish from CS. CAT activity was reduced by 51%, 55%, 47%, and 35% in kidney, liver, heart, and gills of O. niloticus from WN. The GST activities in kidney, liver, and heart of O. niloticus from WN were elevated by 34%, 48%, and 32%, respectively. However, significant fall (49%) in gills of fish was noted from WN compared to fish from CS. GSH levels were increased by 44%, 36%, and 38% in kidney, liver, and heart, respectively, but decreased by 30% in gills. MDA levels of O. niloticus were significantly increased in kidney, liver, and heart in fish from WN. Data indicated that WN is polluted mainly by industrial and urban discharge of liquid waste products.     

Impact of industrial effluents on the biochemical composition of fresh water fish Labeo rohita

In acute toxicity (96 hr) experiment the fingerlings of freshwater fish Labeo rohita was exposed to tannery, electroplating and textile mill effluents. The LC0 and LC50 concentrations were 15% and 20% for tannery effluents, 3% and 6% for electroplating effluents and 18% and 22% for textile mill effluents respectively. It was found that, electroplating effluent was more toxic than tannery and textile mill wastes. After acute toxicity experiments for different industrial effluents, various tissues viz. gill, liver, muscle and kidney were obtained separately from control, LC0 and LC50 groups. These tissues were used for biochemical estimations. The glycogen content in all the tissues decreased considerably upon acute toxicity of three industrial effluents except muscle in LC50 group of tannery effluent and kidney in LC50 group of textile mill effluent, when compared to control group. The total protein content decreased in all tissues in three effluents except gills in LC50 group of tannery effluent, kidney in LC50 group of electroplating effluent and kidney in LC0 group of textile mill effluent. In general total lipid content decreased in all tissues after acute exposure when compared to control group. The results obtained in the present study showed that, the industrial effluents from tannery, electroplating and textile mills caused marked depletion in biochemical composition in various tissues of the fish Labeo rohita after acute exposure.     

Toxicity of cypermethrin on total lipids and free fatty acids in liver,muscle, kidney and ovary of Clarias batrachus (L) and recovery response

Alterations in the levels of lipid metabolites, total lipids and free fatty acids, were studied in physiologically important tissues viz; liver, muscle, kidney and ovary of a freshwater edible fish Clarias batrachus. The fish was exposed to sublethal concentration (1/3 of LC50 value for 96?h) of a synthetic pyrethroid insecticide, cypermethrin for 1, 5 and 10 days. After 10 days of exposure, fish were released into fresh water and total lipids and free fatty acids were determined at intervals of 1, 5 and 10 days to assess fish recovery response after cessation of cypermethrin exposure. Fish showed an increased rate of lipogenesis in liver, muscle, kidney and ovary during the exposure period followed by a decrease after transfer of fish into fresh water. There was also an elevation in liver and kidney free fatty acids contents, while the muscle and ovary free fatty acid contents were reduced during exposure period. The alterations in free fatty acids were restored to near normal values after 10 days of cessation of exposure.     

Profiles of acid and alkaline phosphatases in the prawn Macrobrachium malcolmsonii exposed to endosulfan

The present study was performed to determine the toxic effects of endosulfan on the quantitative and qualitative aspects of acid and alkaline phosphatases (ACP and ALP) in Macrobrachium malcolmsonii. Intermoult juvenile prawns were exposed to 32.0 ng/l of endosulfan for a period of 21 days. Samples were taken from the hemolymph, hepatopancreas, gills and muscle of test prawns on the 21st day. The content of ACP and ALP in the hepatopancreas of test prawns were found to be higher in comparison to respective controls. The levels of these enzymes in the hemolymph, gills and muscle of test prawns were found to be lower than in the same tissues of controls. In non-denaturing PAGE, phosphatases appeared as white bands. The intensity of white bands in the hepatopancreas of test prawns were found to be higher when compared to controls. In the hemolymph, gills and muscle of test prawns, the intensity of white bands were found to be lower in comparison to controls. The results of the present study suggest that endosulfan affects the quantity and quality of ACP and ALP in the tissues of M. malcolmsonii.     

Host glutamine synthetase activities in the giant clam—zooxanthellae symbiosis: effects of clam size,elevated ammonia and continuous darkness

Host tissues and zooxanthellae of the giant clam Tridacna gigas contained glutamine synthetase, with the highest transferase activities present in the gill, followed by the kidney, mantle, zooxanthellae, foot, heart and adductor muscle, in that order. Synthetase activities of glutamine synthetase in host tissues and zooxanthellae were in a similar order, but the differences were not so marked. Host tissues also contained hexokinase, glucose-6-phosphate dehydrogenase and malate dehydrogenase. Highest hexokinase activities were present in the heart, followed, in order, by the gill, mantle, adductor muscle and foot. Highest glucose-6-phosphate dehydrogenase activities were present in the gill, followed by the mantle, heart, adductor muscle and foot. All tissues assayed contained high malate dehydrogenase activities. There was no detectable glutamate dehydrogenase activity. Glutamine synthetase activity in gill and mantle tissue decreased by 1.6% with every 1 cm increase in clam size. Host glutamine synthetase activity decreased by 80% in gill tissue and by 45% in mantle tissue in clams which were maintained for 8 d in continuous darkness. Similar effects were found when clams were kept in light in the presence of elevated ammonia concentrations. It is suggested that both host and symbionts are nitrogen-deficient in small clams and that host glutamine synthetase plays a role in ammonia assimilation by the intact association.     

Influence of insecticidal derivative (cartap hydrochloride) from the marine polycheate on certain enzyme systems of the fresh water fish Oreochromis mossambicus

The activities of phosphatases and transaminases were studied in muscle and liver of the fresh water fish, Oreochromis mossambicus on exposure to different sublethal concentrations (0.25, 0.5, 0.75 and 1 mgl(-1)) of cartap hydrochloride (insecticidal derivative from marine polycheate) for 96 h. There was an overall decrease in phosphatases and transaminases activity in muscle and liver of the fish subjected to cartap hydrochloride.     

Histopathological impact of industrial wastewater on the vital organs of Oreochromis mossambicus

The acute toxicity of paper mill wastewater to Oreochromis mossambicus was investigated with the lethal concentration (LC50) value 6.5% for 96?h exposure. This concentration was used as a baseline to study the effects of paper mill effluent on histopathological changes in gills, liver, kidney, and brain of fish. In the gills, filament cell proliferation, cellular infiltration, hemorrhage, and epithelial lifting were observed. In the liver, vacuolation of hepatocytes and necrosis were noted. In kidney, exfoliation and swollen with pyknotic nuclei were identified. Similarly, the brain also showed enlarged pyramidal cells, binucleated nuclei, vacoulation, and necrosis. These changes occurred predominantly in 21days following exposure of fish to the industrial waste water. Paper mill wastewater was found to be highly toxic to fish.     

镉在鲤鱼组织内的蓄积及对血浆指标的影响

随着工业的迅速发展,水环境中的镉污染日趋严重,镉的蓄积性强,毒性高。为了进一步研究镉在鱼类不同组织内的蓄积及其对血浆指标的影响,以鲤鱼(Cyprinus carpio)为受试生物,设置3个浓度梯度,镉浓度分别为0(对照组)、5和50μg·L-1,试验周期为30d。结果显示,随着暴露时间的延长,染毒组鲤鱼鳃、肝胰脏和肾脏中镉蓄积量与对照组相比均显著升高(p<0.05),其中肾脏蓄积量最大,其次为肝胰脏和鳃,且50 μg·L-1染毒组各组织镉蓄积量显著高于5 μg·L-1染毒组(p<0.05);30d时,5和50 μg·L-1染毒组鳃、肝胰脏和肾脏中镉蓄积量分别为对照组的12.3和43.5倍、5.1和27.3倍、11.9和70.8倍;鲤鱼肌肉中仅检测到微量镉(0.02～0.04mg·kg-1),且暴露时间和镉暴露浓度不影响肌肉中镉的蓄积量。整个试验期间,各染毒组血浆中钙和磷含量、超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量和谷草转氨酶(GOT)活性与对照组相比无显著差异(p>0.05)。研究表明,不同程度的水体镉污染均能造成鲤鱼各组织(肌肉除外)内较高浓度的镉蓄积,但对血浆指标无显著影响。     

Lethal effects of elevated pH and ammonia on juveniles of neotropical fish Colosoma macropomum (Pisces, Caracidae)

Ammonia is the main nitrogenous waste material excreted by gills, then is oxided first to nitrite and then to nitrate. The proportion of ionized-un-ionized ammonia depends on pH and temperature, when this variables increase in a solution containing ammonia the equation goes to left, so the proportion of NH3 increases and the solution becomes more toxic. The purpose of this study was to investigate the acute lethal effects of elevated pH and ammonia on tambaqui juveniles. With a constant ammonia concentration of 5.0 mg/l NH3, there was no mortality a pH of 6.0 (control) and 7.0; but was of 10-20% a pH of 8.0 and 100% at 9.0. The lethal effects of elevated pH and un-ionized ammonia should be recognized as a potential factor contributing to the variable success of tambaqui production ponds, but this species is highly resistant in comparison with other freshwater fish.     

Alteration of male reproductive system in rats fed on red or white meat from tuna fish caught in the Gulf of Gab��s in Tunisian coast

Fish, a widely claimed healthy food for humans, could also pose problems to health due to (1) accumulation of pollutants, especially heavy metals, (2) presence of marine toxins such as tetrodotoxin, ciguatoxin or okadaic acid and (3) metabolic production of large amount of uric acid which may crystallize in kidney or in articulations. As tuna fish represents a large part of the traditional food in some countries, the possible impact of its consumption on public health was investigated, with special attention to biochemical and histological alterations related to the genital function. For that purpose, white or red muscle from tuna fish was added for 60 days to the diet of male rats, and attention was paid to biochemical and histological alterations related to the genital function. Feeding rats with white muscle, and much more markedly with red muscle known to be more metabolically active, resulted in (1) an elevated uric acid level in blood, (2) an increase in lead level in testis, (3) an atrophy of the genital tract, including testes, epididymis, prostate and seminal vesicles, (4) a lowering of plasma testosterone level, (5) a decrease in spermatozoids number and motility, (6) an oxidative stress in testes including an increase in lipids peroxidation level and enhanced superoxide-dismutase, catalase and glutathione-peroxidase activities. We conclude that consumption of tuna fish meat, especially the dark one, should be reduced.     

Effects of cadmium on metallothionein and histology in gills of tilapia (Oreochromis niloticus) at different salinities

The objectives of this study were to evaluate the effects of sublethal cadmium concentrations on the levels of cadmium, metallothionein (MT) and histological changes in gills of East Java strain tilapia (Oreochromis niloticus) at different salinity levels. The levels of cadmium in control gills were not significantly different at 0, 5 and 10 practical salinity unit (PSU). The cadmium concentrations in gills of cadmium-exposed fish were significantly higher at 0 PSU than at 5, 10 and 15 PSU. The MT concentrations in control gills were not significantly different at 0, 5, and 10 PSU. The MT concentrations of cadmium-exposed fish were significantly higher than those in respective control groups at 0, 5 and 10 PSU. Significant gill damage occurred in fish exposed to cadmium at lower salinity. The epithelial lifting was noted at gills of fish exposed to 2.5 mg/L of cadmium at 0 PSU, and telangiectasis was observed at gills exposed to 5 mg/L of cadmium at 0 PSU. The level of gill damage decreased with increasing salinity of media. The increased MT and histological changes in gills of our findings could be a protective response of animals to toxic effect of cadmium.     

Comparison of Zn, Cu, Pb, Ni, Cr, Sn, Mo Concentrations in Tissues of Fish (Roach and Perch) from Lake Baikal and Bratsk reservoir, Russia

Data on Zn, Cu, Pb, Ni, Cr, Sn, Mo concentrations in some food fish in Baikal Lake and Bratsk reservoir have been compared. The muscles, skin and gills of roach and perch (Rutilus rutilus and Perca fluviatis L.) were analysed. The conditions of atomic-emission analysis, detection limits, reproducibility, coefficients of transformation from the wet to dry mass and to an ash residue are reported. To verify accuracy, the results of reference samples OK-1 (Baikal perch) and OM-1 (Baikal roach) were used along with atomic-absorption and neutron-activation results of ashed and dried samples. The observed range of concentrations in tissues exceeds the probable analytical errors and reflects natural variability. The content of Zn, Cu, Pb, Ni and Cr in tissues of fish collected in the Bratsk reservoir from the conventionally uncontaminated and polluted sites correspond to the concentrations in tissues of similar fish from Lake Baikal. The latter are normal for fish of weakly mineralised oligotrophic reservoirs. The ranges of concentration in studied fish (roach and perch) consist of mg kg^–1 dry wt: in muscles-Zn(14–28), Cu(2.2–4.7), Pb(0.30–0.61); in skin-Zn(94–119), Cu(1.2–1.4), Pb(0.16–0.08); in gills-Zn(70–280), Cu(2.0–7.4), Pb(0.19–1.2).     

Nickel induced changes on some aspects of protein metabolism in the tissues of Pila globosa

Some aspects of protein metabolism were studied in foot, hepatopancreas and mantle tissues of snail, Pila globosa on exposure to lethal concentration for 2 days (336.7 mg/L) and sublethal concentration (67.34 mg/L) of nickel for 1, 5 and 10 days. Total, structural and soluble proteins decreased significantly and to continence, this the levels of amino acids and protease activity increased in all the tissues of snail at all time points examined. Activities of AAT (Aspartate aminotransferase) and AlAT (Alanine aminotransferase) showed contrasting trends of inhibition and elevation during lethal and sublethal concentrations of nickel treatment. GDH (Glutamate dehydrogenase) activity was increased in all the tissues with increase in exposure time. Level of ammonia decreased in snails at sublethal concentration, but increment was observed in lethal concentration along with increased urea content. Under lethal and sublethal exposures, the changes in all the parameters were more pronounced in hepatopancreas followed by foot and mantle. At most instances, snails in the lethal medium were affected more compared to sublethal concentration.     

Foodweb modeling for polychlorinated biphenyls (PCBs) in the Twelvemile Creek Arm of Lake Hartwell,South Carolina,USA

PCBs from the Sangamo-Weston Superfund Site near Clemson, South Carolina, USA, were released into the Twelvemile Creek Arm of Lake Hartwell until the early 1990s. Monitoring data have shown that while PCB concentration in sediments declined since 1995, PCB concentrations in fish have remained elevated, e.g., largemouth bass (Micropterus salmoides) concentrations have ranged from 5 to 10 ppm. The EPA aquatic ecosystem model AQUATOX was applied to this system to better characterize foodweb dynamics that lead to biomagnification of PCBs. The model was calibrated with observed fish biomass data. Simulated PCB loading over a 12-year period provided a reasonable fit to observed PCB data in fish. The model demonstrated that contaminated labile detritus loaded to the system was incorporated into the foodweb rather than deposited, thereby maintaining the PCB concentrations in fish while concentrations in the sediment declined. A dominant PCB pathway was from detritus to daphnia to shad to largemouth bass. Fish PCB concentrations showed moderate sensitivity to toxicant parameters; model runs incorporating uncertainty in these parameters predicted recovery (<2 ppm PCB) for all species in the range of years from 2008 to 2013. The high sensitivity of the model to parameters related to growth strongly affected PCB concentrations in fish and should be considered in future AQUATOX applications.     

Municipal wastewater-induced histopathological lesions in gills of freshwater fish Labeo rohita – A SEM study

The fingerlings of fish Labeo rohita were subjected to chronic (15, 30, and 60 days) and recovery (60 days) experiments for histopathological studies using sublethal concentrations (35.4%, 26.6%, and 17.7% v/v) of municipal wastewater of Tung Dhab drain, Amritsar, India. Control fish were maintained for same exposure periods using tap water. Scanning electron microscopic studies exhibited dose- and duration-dependent alterations on gill surface ultra-structure. Control fish exhibited functionally normal gills with normal mean degree of tissue change. Fifteen different types of lesions were identified out of which 9, 5, and 1 were of the stage I, II, and III, respectively. The mean degree of change values in the treated groups ranged from 14.8 ± 0.5 (17.7%, 15 days) to 116. ± 17 (35.4%, 60 days) demonstrated gill damages of slight to irreparable lesions. The recorded alterations were epithelial lifting and intraepithelial edema, reduction of water spaces, lamellar fusion, lamellar telangiectasia, swelling and fusion of filaments, sloughing of lamellar epithelium, hypertrophy and hyperplasia of mucous and chloride cells, and necrotic lamellae. The recovery experiments showed positive improvement as the intensity of damage was less than recorded for 60 days of treatment. This study clearly indicated toxicity of drain water to fish at cellular and organ level. The study recommends environmental agencies to make and enforce decisions regarding improvement of water quality of Tung Dhab drain, and further incorporating histopathological studies as an analytical tool.     

Concentration of heavy metals in the food web of Lake Egirdir, Turkey

The concentration of heavy metals (Cr, Cd, Hg and Pb,) was determined by atomic absorption spectrophotometry in sediment, water, plankton and fish samples from Lake Egirdir in South-Western Turkey. Lake Egirdir is an important bird nesting and visiting areas, and it is also used as irrigation and drinking water source. The heavy metal concentrations were in the order Cd > Pb > Cr > Hg in water, Cr > Pb > Cd > Hg in sediment, Pb > Cd > Cr > Hg in plankton, Cd > Cr > Pb > Hg in the muscle and Cd > Pb > Cr > Hg in the gills of Ctenophatyngodon idella. The significant differences of concentrations occurred in water, sediment, plankton and fish tissues (Chi square test, p < 0.05). The concentrations of the heavy metals in water and fish tissues of three years old, were above the maximum permissible level for human consumption.     

Assessment of lead and cadmium residues in farmed fish in Machakos and Kiambu counties,Kenya

Lead (Pb) and cadmium (Cd) concentrations were determined in muscle, gonad, liver and brain of tilapia fish caught from fish ponds in Machakos and Kiambu counties in Kenya. A total of 217 fish samples were randomly sampled from the two counties. Acid digestion method and atomic absorption spectrophotometer were used for analysis. Heavy metal concentrations varied significantly depending on the type of tissue analyzed. Generally, the highest concentration of Pb was detected in brain and the liver. Fish organs contained Pb in the following order: brain > liver > muscle > gonad, while Cd followed the order: brain > liver > gonad > muscle. Kiambu county recorded higher concentration of the studied heavy metals compared to Machakos county although statistically there was no difference. Lead and Cd content in both counties studied exceeded the maximum allowable limit. The study recommended controlling industrial and agricultural effluents into surface water and proper sitting of ponds to minimize the risk of contamination of farmed fish by heavy metals.     

Lead- and cadmium-induced histopathological changes in gill,kidney and liver tissue of freshwater climbing perch Anabas testudineus (Bloch, 1792)

The objective of this study was to examine the toxicological effect of two major heavy metal pollutants, lead chloride (PbCl₂) and cadmium chloride (CdCl₂), in the freshwater climbing perch, Anabas testudineus. Fish were exposed to 1.0 and 2.0 mg/L both metals and histopathological changes in gill, kidney and liver tissues were studied. Major changes observed in gill tissue were epithelial lifting, proliferation of epithelial cells, fusion of secondary lamellae, hyperplasia and hypertrophy of mucous cells, and necrosis of epithelial cells. Cell necrosis, degenerated kidney tubules, congestion, lymphocytic infiltration and vacuolation were the major abnormalities observed in kidney tissue. The most conspicuous changes in liver were darker nucleoli, irregularly shaped hepatocytes with dilated blood capillaries, and focal as well as single necrosis. Fish specimens exposed to PbCl₂ exhibited pronounced changes in all tissues examined compared with those exposed to CdCl₂. It is evident from this study that heavy metals can cause significant histopathological changes in fish tissue.     

水暴露下氟在西伯利亚鲟稚鱼硬骨和软骨中的积累和消除

采用静态水暴露试验方法,设置0.26(对照)、3.1、7.8、18.7、51.8mg·L-1氟离子(F-)5个试验组暴露西伯利亚鲟稚鱼,暴露90d后转移至清水中培养30d,检测了这2个阶段鱼体硬骨和软骨中氟离子含量,探讨了氟离子在西伯利亚鲟稚鱼硬骨和软骨中的积累与消除规律,以及氟离子对鱼体生长的影响.结果表明,随着氟离子浓度的增加和暴露时间的延长,氟在西伯利亚鲟稚鱼硬骨和软骨中的含量显著增加,暴露90d时各暴露组硬骨和软骨中氟含量均显著高于对照组;西伯利亚鲟稚鱼暴露在较高浓度氟离子(7.8、18.7和51.8mg·L-1)中90d,生长速度(体重)显著下降;经过30d清水培养后,较高浓度暴露组(18.7和51.8mg·L-1)西伯利亚鲟稚鱼硬骨的氟含量显著下降.由此结论:氟在西伯利亚鲟稚鱼硬骨和软骨组织中具有较高的生物蓄积作用;转移至清水中饲养后,蓄积的高浓度的氟可从硬骨中排出.