Relative toxicity of spent lubricant oil and detergent against benthic macro-invertebrates of a west African estuarine lagoon

The relative acute toxicity of spent lubricant oil and detergent was evaluated against hermit crab, Clibanarius africanus (Aurivillus) and periwinkle, Tympanotonus fuscatus (L) from the Lagos lagoon in laboratory bioassays. Based on the derived toxicity indices, the detergent (96 hr LC50 = 5.77ml/l) was found to be 1.73 times more toxic than spent engine oil (96 hr LC50 = 10.01 ml/l) when acting singly against C africanus and 18.73 times (96 hr LC50-48.67 ml/l) more toxic (96 hr LC50 = 911.57 ml/l) when acting singly against T. fuscatus. On the basis of the computed susceptibility factors, C. africanus was found to be about eight times and ninety-one times more susceptible to the toxic effect of detergent and spent lubricant oil respectively. The randomized analysis of variance (ANOVA) showed that there was significant difference (Fcal 58.83 Ftab 3.87; DF 13; p > 0.05) between all treatments of spent lubricant oil and detergent during the 96 hr exposure period of test animals. At 5% level of significance the Student Neuman-Keuls (SNK) test further revealed significant differences in the mean mortality response of test animals exposed to toxicants at all concentrations and untreated control. The results obtained in this study suggest that the estuarine benthic macroinvertebrates, which play key roles in the environment, may serve as useful in-situ sentinels for biomonitoring studies of petroleum pollutants in fragile aquatic ecosystems such as the Lagos lagoon.     

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.     

多效唑对水生生物的急性毒性评价研究

本文以斜生栅藻、大型水蚤和草鱼为试验生物,研究植物生长调节剂多效唑对水生生物的急性毒性效应。多效唑对斜生栅藻EC_(50)-96h为20.62mg/l;对大型水蚤LC_(50)-48h为21.86mg/h;对草鱼苗静态生物检测结果为LC_(50)—120h 16.33mg/l,流水生物检测结果为LC_(50)-96h 14.36mg/l,LC_(50)-120h 9.13mg/l。经多效唑处理后,藻的细胞形态也发生明显改变。根据农药的实验室毒性评价划分标准,多效唑对三种生物的毒性均属低毒;田间安全性预评价的结果也表明其毒性为低毒,故认为多效唑是一种对水生生物危害较小的农药。但其慢性毒性及长期积累效应,尚有待进一步研究。     

In vitro-Screening von Gefahrstoffen in der Arbeits- und Umweltmedizin

Chromium, especially the metal and its trivalent and hexavalent compounds, are of great industrial interest. As a matter of fact, chromium workers have an occupational risk. While trivalent chromium compounds are of low toxicity, the hexavalent compounds are strong oxidants which cause not only a direct tissue damage (=acute toxicity), but also possess a carcinogenic, mutagenic and teratogenic potential (=chronic toxicity). Since the kidney is the main target organ after oral and/or dermal uptake of hexavalent chromium is the kidney, tubular necrosis might be the result of an acute toxification. This report presents anin vitro assay with cultured renal epithelial cells which allows the evaluation of the acute toxicity not only of trivalent and hexavalent chromium compounds, but also of various hazardous substances used in industrial production process. As shown here, an acute toxic effect was not detectable for the trivalent chromium (chromium (III)-chloridehexahydrate) within 24 h of exposure to concentrations as high as 200 μmol/l. In contrast, renal epithelial cells which were exposed to hexavalent chromium (potassium chromate) for the same time period exhibited marked signs of toxicity such as a rounding and detachment of the cells from the floor of the culture plates, an elongation and perinuclear development of vacuoles in the vital cells which were still attached, as well as a cells swelling and cellular fragments caused as a result of necrotic cell death and subsequent lysis. This toxic effect was already observed at concentrations above 5 μmol/l. In conclusion, thein vitro assay might be a good tool for the screening of hazardous substances in industrial medicine. More-over, by using additional tests, the chronic toxicity of such substances can also be examined. The selection of specific cell strains such as hepatocytes, neural cells etc. also allows the evaluation of toxic effects in individual organs. Thein vitro assay can not only be applied for the investigation of basic mechanisms of toxification and detoxification of specific compounds, but also delivers a basis for the screening of the reactivity of individual hazardous substances. Finally, the assay would allow a reduction in animal experiments as well as the simultaneous testing of a reactivity to multiple, hazardous substances.     

Cytotoxicity assessment of monocrotophos in Paramecium caudatum and Oxytricha fallax

Experiments were conducted to evaluate the toxic effects ofmonocrotophos in ciliate models Paramecium caudatum and Oxytricha fallax. In acute toxicity studies higherconcentrations of monocrotophos caused marked increase in mobility of cells exhibiting rocking movements within two mins of exposure but were decreased after 30 mins. LC50 value by mortality curve for 3 hr acute toxicity test of Oxytricha fallax and Paramecium caudatum was found 307.744 +/- 33.27 mg l(-1) and 332.284 +/- 57.52 mg l(-1) respectively. Oxytricha fallax was found sensitive than Paramecium caudatum to monocrotophos. In acute exposure cells showed deformities such as swelling, oval shaped deformity and in higher concentrations shortening of longitudinal axis with blackening of cytoplasm occurred. The length of paramecia was reduced prominently. Similarly enlargement of contractile vacuole and stress egestion of food vacuoles was also observed. The morphological studies showed the changes in shape, size, colour and width of Paramecia and Oxytricha. Frequencies of macronuclear aberrations were significant showing deformities such as rod shaped, elongation, fragmentation, diffusion and total absence of nucleus and were concentration dependent. The data provided in the present study on interaction of pesticides with nuclear structure can be of immense value because most of these pesticides have been reported to have carcinogenic, mutagenic and teratogenic properties.     

酰胺类除草剂对铜绿微囊藻的生长影响及氧化损伤效应

酰胺类除草剂的广泛使用对水生生态环境构成了潜在风险。为探究其对藻类的毒性作用,以铜绿微囊藻为对象,分别从藻类生长和氧化损伤效应角度探讨了甲草胺、乙草胺和丁草胺对铜绿微囊藻的毒性影响。实验结果显示,酰胺类除草剂对藻类的影响存在明显的滞后效应和剂量–效应关系,低浓度暴露组刺激藻类增长,高浓度表现为抑制作用;3种酰胺类除草剂增加了铜绿微囊藻的氧化压力,并随着暴露时间的延长和浓度的增加而增强。其中,藻体内过氧化脂质降解产物丙二醛(MDA)含量明显增加,同时超氧化物歧化酶(SOD)和过氧化物酶(POD)活性也显著增强。经96 h暴露后,甲草胺(32.0 mg·L~(-1))、乙草胺(32.0 mg·L~(-1))和丁草胺(15.0 mg·L~(-1))暴露溶液中相对MDA含量分别为138%、204%和154%,相对SOD活性分别为116%、87%和115%,相对POD活性分别475%、278%和627%。结合生物量及氧化损伤效应实验结果可知,3种除草剂对铜绿微囊藻的毒性大小顺序为丁草胺乙草胺甲草胺。     

In situ evaluation of the genotoxic potential of the river Nile: I. Micronucleus and nuclear lesion tests of erythrocytes of Oreochromis niloticus niloticus (Linnaeus, 1758) and Clarias gariepinus (Burchell, 1822)

This study aimed to investigate the genotoxic potential of chemicals present along the course of the river Nile using frequencies of micronuclei (MN) and nuclear lesions (NL) in erythrocytes of Nile tilapia Oreochromis niloticus niloticus and African catfish Clarias gariepinus, as biomarkers. Results showed that most of the physicochemical parameters detected and heavy metal concentrations were significantly higher in the water collected from the estuaries of the river Nile compared to other sites of the upper Nile. The frequencies of MN and NL in peripheral blood erythrocytes of Nile tilapia and African catfish were significantly higher in estuary sites in Damietta and Rosetta compared to upper sites. The lowest level of genotoxicity was observed at two sites (Aswan and Kena), considered to be less contaminated. Our results suggested that higher frequencies of MN and NL determined at Damietta and Rosetta sites may be indicative of damage produced by pollutants in these areas. The most remarkable result was that MN and NL frequencies appear to be strongly related to water quality at different sites examined, indicating that MN frequencies may serve as a reliable biomarker for testing genotoxicity in situ. The positive correlation between MN and NL induction suggested that NL may be a useful complementary assay for genotoxicity analyses when fish are used as experimental animals. It was also found that seasonal variations in MN and NL frequencies might contribute to a better understanding of genotoxic responses in the field. The use of fish as indicator organisms for monitoring the presence of genotoxic-inducing contaminants in the environment seemed justified because the effects of exposure to a “complex mixture” such as river water were obtained. Nile tilapia appears to be a more suitable bioindicator species than African catfish in studying genotoxic chemical pollution in the river Nile attributed to a higher sensitivity.     

Effects of arsenic on osmoregulation in the tilapia Oreochromis mossambicus reared in seawater

The effects of arsenic (As₂O₃) on plasma osmolarity, Na and K concentrations, the activity of gill Na–K-ATPase, and on the ultrastructure of gill chloride cells were compared between seawater tilapia (Oreochromis mossambicus) and freshwater tilapia in the Institute of Zoology, Academia Sinica, between 1989 and 1991. Arsenic was found to be more lethal in seawater tilapia [96 h LC₅₀ (median lethal concentration): 26.5 ppm] than in freshwater ones (71.7 ppm). No significant effect was found on plasma ion concentrations and osmolarity, enzyme activity or the ultrastructure of chloride cells in freshwater tilapia after 96 h exposure to 70 ppm arsenic. In contrast, 96 h exposure to 15 ppm arsenic caused evident effects in seawater tilapia: an increase in plasma osmolarity and activity of gill Na–K-ATPase, as well as better development of the chloride cell tubular system. These data suggest that the lethal effect of arsenic may be partially attributed to a hydromineral disturbance in seawater tilapia, but in freshwater tilapia arsenic perhaps causes destruction in some physiological mechanisms other than osmoregulation. The activation of gill Na–K-ATPase and chloride cells in seawater tilapia appears to indicate an adaptation in the osmoregulatory mechanism to arsenic exposure, i.e., to enhance secreting ions or arsenic in the gills.     

Scanning electron microscopy study of the gills,scales and erythrocytes of Anabas testudineus upon exposure to chlorpyrifos

The present study was undertaken to assess the toxicity of sublethal concentrations (125, 250, and 375 µg L^?1) of chlorpyrifos on Anabas testudineus for 21 days. The morphological changes on the gills, scales, and erythrocytes of A. testudineus were observed using scanning electron microscopy. Gill alterations included highly active mucous cells, epithelial hyperplasia, and fusion of secondary lamellae. The scales showed damaged lepidonts. Oozed out cytoplasmic content and lobopodial projections were observed in the erythrocytes after exposure to chlorpyrifos.     

Evaluation of 3-hydroxy-benzo[a]pyrene levels in Nile tilapia (Oreochromis niloticus) after waterborne exposure to Benzo[a]pyrene

3-Hydroxy-benzo[a]pyrene (3-OH-BaP), a toxic compound with the ability to covalently bind with the macromolecules (proteins and DNA), is one of the major phenolic metabolites of benzo[a]pyrene (BaP). The purpose of this study was to evaluate the presence of 3-OH-BaP in the bile and plasma of Nile tilapia by HPLC with fluorescence detection, after waterborne exposure to BaP (10 and 100?µg?L^?1). Metabolites were detected in bile and plasma, and conjugates of 3-OH-BaP (glucuronide and/or sulphate conjugates) were the majority forms in both biological fluids, glucuronide 3-OH-BaP being the main metabolite in bile. Our data suggest that extrahepatic tissues as intestine or gill are important in BaP metabolism and need to be the considered sources of metabolites released into the blood. Although, low levels of 3-OH-BaP in toxic form (free form) were detected in plasma, one cannot exclude the possibility of circulating the levels leading to adverse effects.     

Acute toxicity of mercury to the fingerlings of Indian major carps (catla, rohu and mrigal) in relation to water hardness and temperature

In the present study short-term (96 hr) toxicity of mercury in relation to water hardness (270 and 560 mg/l) and temperature (16 degrees C and 35 degrees C) to the fingerlings of Indian major carps, i.e. catla, rohu and mrigal has been evaluated using static bioassay. The LC5o indicates that both water hardness and temperature played significant role in mercury toxicity. The test fishes were found most resistant with water hardness of 560 mg/l at 16 degrees C as compared to that of water hardness of 560 mg/l at 35 degrees C and water hardness of 270 mg/l at both the temperatures, i.e. 35 and 16 degrees C. Whereas the order of relative sensitivities of these fishes for mercury ions were recorded as catla>rohu>mrigal. The safe concentrations of mercury were ranged in between 12.133 to 19.689 microg/l for catla; 64.039 to 82.555 microg/l for rohu and 73.510 to 89.585 microg/l for mrigal for both the water hardness and temperature.     

Effects of tributyl-tin on a marine microalga, Tetraselimis suecica

Marine pollutants induce changes in microalgal metabolism. In this study effects of tributyl-tin chloride (TBTCl) on a marine microalga Tetraselmis suecica was studied. The changes induced by TBTCI on growth rate, viability and biochemicals were assessed. In acute exposure to TBTCl, EC50 estimated for 24 hr was 2.02 microg ml(-1), whereas total lethality was observed at 4 microg ml(-1). In chronic exposure to TBTCl, at higher concentrations (0.5-1 microg ml(-1)) growth rate, chlorophyll pigments, carbohydrate and protein contents were reduced. The results of this study indicate that TBTCl toxicity made drastic changes in growth and biochemical composition of T. suecica.     

Ultrastructure changes in hepatocytes of catfish Clarias gariepinus from Lake Mariut, Egypt

In the present study, specimens of catfish (Clariidae) were collected from a polluted location (Main Basin) and a relatively clean area (East Basin) in Lake Mariut, one of the Nile Delta Lakes in Egypt. Fifteen fish were taken from each site. Liver preparations of fish from the two sources were comparatively examined for cellular changes using transmission electron microscopy. Fish hepatocytes from the polluted area showed accumulation of the heterochromatin, enlarged nucleoli, and an extremely folded nuclear envelope. Perichromatin granules were increased and progressively formed small clusters closely associated with patches of heterochromatin. In the cytoplasm, fractionation, dilation, and vesiculation of rough endoplasmic reticulum (RER), and elevated amounts of smooth endoplasmic reticulum (SER) tubules were noted. The most frequent pathological modifications were the swelling of mitochondria, cristae regression and changes in the electron-transparency of the matrix. Lysosomes showing myelin-like stacks of membraneous material (phospholipidosis), glycogenosomes (i.e., glycogen rosettes enclosed by membranes) and cytoplasmic myelinated bodies were strongly developed. Furthermore, increasing numbers of secondary lysosomes with degraded cell organelles were found. With reference to the storage vesicles, there appeared to be an increase in the lipid droplets (lipidosis) within many hepatocytes. This study reinforces the need to select representative sentinel species from different habitats for biomonitoring purposes and it provides further support for the use of biomarkers in assessing the health of aquatic ecosystems.     

Differential response of Tilapia guineensis fingerlings to inorganic fertilizer under various salinity regimes

The influence of salinity on the response of the estuarine teleost, Tilapia guineensis fingerlings to acute toxic effects of inorganic nitrogen-phosphorus-potassium (NPK) (15: 15: 15) fertilizer was investigated using semi-static bioassay. The toxicity of NPK fertilizer was found to increase significantly with increase in the salinity level from 0.05 %. to 32.4 %o. The 96 hr LC50 value at salinity of 32.4 %o was 0.11 mg/l and was found to be significantly (p < 0.05) higher than the toxicity values at any other salinity level of media evaluated. The implication of the findings is that pollution control standards and/or safe limits for brackish water ecosystem should consider variations in salinity regimes for greater relevance and reliability.     

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.     

Piscicidal potential of mesocarp of neem plant (Azadirachta indica L.) fruit on hybrid, "Heteroclarias"

The piscicidal potential of water-extract mesocarp of Azadirachta indica (L) was studied in static bioassay experiment with continuous aeration to determine its acute toxicity The mortality rate and opercular ventilation under laboratory conditions over 96 hr exposure were monitored. The 96 hrLC50 was 81.28 mgl(-1) while the threshold value was 21.13 mgl(-1). The fish exhibited respiratory distress (such as gasping air), loss of appetite, loss of balance and erratic swimming prior to mortality.     

Induction of oxidative stress by non-lethal dose of mercury in rat liver: possible relationships between apoptosis and necrosis

Sprague Dawley strain of male rats weighing 200 +/- 10.0 g, were exposed intramuscularly to non-lethal dose of mercury for short acute duration of 24 and 48 hr. Mercury treatment increased thio-barbituric acid reactive substance (TBARS) and conjugated diene (CD) content with increase in duration when compared with control. This reflects possible increase in lipid peroxidation, revealing that sufficient intoxication was generated by non-lethal dose of mercury. Furthermore, mercury treatment decreased tissue glutathione (GSH) content to 2.07 and 1.49 microg GSH mg protein(-1) with concomitant decrease in glutathione-S-transferase (GST) activity by 26.06 and 36.40% after 24 and 48 hr of exposure respectively. The elevations of aspartate transaminase (AST) and alanine transaminase (ALT) levels measured exhibited increase of 287.5 and 214.5% after 48 hr of exposure respectively which were found to be highly significant compared with control. Western blot analysis indicated upregulation of caspase-9 and upsurge in effect or caspase-3 activity leading to apoptosis. The concluded findings of the present investigation suggests possible role of early mercury exposure in inducing oxidative stress mediated apoptosis in mammalian model systems as an indicator component of environmental toxicology.     

Cadmium accumulation by green algae Cladophora glomerata (L.) Kutz. (Chlorophyta) in presence of Nile tilapia Oreochromis niloticus (L.)

Accumulation of metals by aquatic organisms is mostly affected by other biological components in environments. In this study, cadmium (Cd) accumulation in green algae, Cladophora glomerata (L.) Kutz., exposed to 0.1 and 1.0 mg L^?1 of Cd for 15 and 30 days was examined in laboratory conditions in the presence of Nile tilapia Oreochromis niloticus (L.). The green algae C. glomerata accumulated Cd concentrations as 690 ± 70 and 3430 ± 470 mg kg^?1 on day 15, and 1130 ± 180 and 6830 ± 1540 mg kg^?1 on day 30. There were significant increases (p < 0.05) in metal accumulation by green algae as the exposure time and metal concentration increased. The results also indicated that the presence of Nile tilapia in the medium led to a significant Cd accumulation in the green algae compared to control (p < 0.05).     

壬基酚与壬基酚聚氧乙烯醚对多刺裸腹溞的复合毒性效应

为了探讨壬基酚聚氧乙烯醚（NP10EO）与其降解产物壬基酚（NP）对多刺裸腹溞的复合毒性效应,在实验室条件下研究了NP和NP10EO单一暴露对多刺裸腹溞的急性毒性和亚慢性毒性,以及两者混合暴露对多刺裸腹溞的联合毒性效应。结果表明：NP和NP10EO两种物质单一暴露对多刺裸腹溞的24 h LC50分别为0.154和3.37 mg.L-1,48 h LC50分别为0.065和2.11 mg.L-1。联合毒性实验中,定义0.5×LC50（NP）＋0.5×LC50（NP10EO）为一个毒性单位（1TU）。NP和NP10EO混合暴露后对多刺裸腹溞的24 h和48 h的LC50分别是0.646TU和0.291TU,联合毒性强度明显高于两种物质单一暴露时的毒性强度。在持续混合暴露条件下,多刺裸腹溞的首次生殖时间延迟、母体体长和初生幼体体长严重缩短、首次生殖数量大幅减少。说明NP和NP10EO对多刺裸腹溞的复合毒性表现出明显的协同效应。     

西维因对雄性罗非鱼(GIFT Oreochromis niloticus)内分泌干扰效应的研究

在实验室条件下研究了西维因对罗非鱼的急性毒性以及在不同暴露浓度下的西维因(0.064,0.8和5mg·L-1)对雄性罗非鱼性腺系数、血清雌二醇、睾酮含量的影响以及对卵黄蛋白原的诱导效应,以期对其环境雌激素效应研究有所贡献。结果表明:西维因对罗非鱼的24、48、72和96h的LC50分别为30.21、25.16、19.76和17.86mg·L-1。长期暴露于低剂量的西维因中,会使雄性罗非鱼精巢系数降低;对其血清雌二醇的合成具有诱导作用,当浓度为0.8mg·L-1时,诱导作用最强,此时血清雌二醇的含量为218.83pg·mL-1;卵黄蛋白原的含量随着西维因浓度的升高,逐渐增多,当处理浓度为5mg·L-1时,达到最大为393.01μg·L-1;随着西维因浓度的升高,睾酮含量逐渐降低,西维因的浓度为5mg·L-1时,睾酮含量达到10.58mol·L-1,差异极显著(p<0.01),这可能是由于西维因对雄性罗非鱼具有雌激素效应。