Retardation of Fin Regeneration in Freshwater Fish Oreochromis mossambicusby Zinc

Regeneration of partially amputated caudal fin was studied in freshwater fish Oreochromis mossambicus exposed to sublethal concentrations of zinc (5.0 mg L^—1 and 10.0 mg L^—1) under ambient laboratory conditions over a period of 20 days. Caudal fin regeneration was measured on 5th, 10th, 15th and 20th day of exposure and after amputation. Significant ( p < 0.05) retardation in fin regeneration was observed on day 5th and 10th in fish exposed to the nominal concentration of 5.0 mg L^—1 Zn, while retardation was found highly significant ( p < 0.01) at all the observations in 10.0 mg L^—1. The maximum inhibition in caudal fin regeneration (20.8 % and 24.3 %) was found during the initial observation at both of the concentrations (5.0 mg L^—1 and 10.0 mg L^—1) of zinc exposure. Later on the regeneration rate was almost as good as in the control group. Thus in this study fin regeneration was significantly inhibited at all time points following Zn exposure as a detrimental effect of Zn to fish. This study demonstrates that fish caudal fin regeneration is a simple assay, sensitive and easy to perform, and can serve as a model to determine the toxicity of pollutants in aquatic environment.     

Acute Toxicity of Some Industrial Effluents in Relation to the Fish Size of Cyprinus carpio (HAM.) and Channa punctatus (BLOCH)

The fish Cyprinus carpio (HAM.) and Channa punctatus (BL.) of the size ranging between 6.0 ± 1.2 cm and 28.0 ± 1.6 cm were exposed to different concentrations of industrial effluents from M/s Punjab Tannery Ltd. (Jalandhar), M/s Spinning Mill Ltd. (Hoshiarpur) and M/s Food Specialist Ltd. (Moga) for evaluating the influence of fish size on the acute toxicity of these effluents. Results indicate that the relative toxicity of the effluents decreased with the increase in fish size from 6.0 ± 1.2 cm to 20.6 ± 1.5 cm. However, for specimens of the size of 28.0 ± 1.6 cm and more, the toxicity of the effluents increased with an increase in fish size. On the basis of the relative toxicity to fish, effluent from Punjab Tannery was found highly toxic and from Food Specialist Industry, the least toxic.     

Zur akuten Toxizität von Trichlorfon gegenüber ausgewählten Wasserorganismen

Two different formulations of Trichlorfon were examined for their acute toxicity in laboratory tests. Cyprinus carpio L., Salmo gairdneri Rich. and the fish food organisms Cyclops spec., Diaptomus spec. and Chironomus spec. were used as test objects. The differences in toxicity between crystalline and technical Trichlorfon were not very large. The recorded lethal concentrations are summarized in graphical representations and tables. After exposure for several hours to lower concentrations of active constituents, the toxicant-damaged fishes regained their original activity of life during a subsequent phase of recovery Tests of fish food organisms with 100 … 200 μg/l Trichlorfon led to death within 48 hours. Also on chironomid larvae Trichlorfon has a lethal effect at 0.2 mg/l within 48 hours. Toxicity is increased by the hardness constituents of the water. As experiments conducted with Crustacea have shown, growth is inhibited only at a certain concentration in the body.     

Development of a laboratory exposure system using marine fish to carry out realistic effect studies with produced water discharged from offshore oil production

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.     

Size related toxicity of industrial effluents to cyprinus carpio (HAM.) and Channa punctatus (BL)

Fish, Cyprinus carpio and Channa punctatus in four sizes (6.0 ± 1.2; 12.5 ± 1.6; 20.6 ± 1.5 and 28.0 ± 1.8 cm in total length) were exposed to industrial effluents from the Sangam Dyeing Factory (Ludhiana), the Sterling Steel and ABC Paper Mills (Hoshiarpur) to evaluate the acute toxicity of these effluents at different fish sizes. Results reveal that the toxicity of industrial effluents decreased with the increased fish size from 6.0 ± 1.2 to 20.6 ± 1.5 cm in length. However, for specimens of the size of 28.0 ± 1.6 cm and more, the toxicity of the effluents increased with an increase in fish size. On the basis of the relative toxicity to fish, effluent from the Sterling Steel Mill was found to be highly toxic to fish and effluent from the Dyeing Factory least toxic except for the fish of 6.0 ± 1.2 cm at which dyeing factory effluent was most toxic and ABC paper mill effluent the least toxic.     

Prediction of bioconcentration and related lethal and sublethal effects with aquatic organisms

It is now well established that the octanol/water partition coefficient (K_0W) can be used to estimate bioconcentration of persistent organic compounds, such as the chlorohydrocarbons as well as PAHs and other hydrophobic substances. However, while these relationships are well established in the laboratory, use in the field often poses a number of problems. In recent studies of contaminants in fish from Australia, bioconcentration has been described using additional information on specimen size, lipid content and fish movement patterns.The use of internal biotic concentration provides an additional new and different perspective on toxicant behaviour as compared to the conventional ambient aqueous concentration-based toxicity measures. The internal lethal concentration for persistent organic compounds approaches a constant value for many compounds, and at these concentrations lethal effects are observed. This constant internal lethal concentration provides a basis for predicting toxicity and its relationship to exposure period. In addition, sublethal effects can be successfully related to the internal biotic concentration.     

Studies on the Acute Toxicity of Zinc to a Freshwater Teleost: Channa punctatus (Bloch)

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.     

Toxicity of Crude Oil to the Survival of the Fresh Water Fish Puntius sophore (HAM.)

The exposure of Puntius sophore to different concentrations of crude oil (200… 4000 ppm) revealed that 4000 ppm was acutely lethal to the fish and mortality did not occur at <500 ppm at 21±1 °C for up to 15 days. The increase in the opercular frequency during exposure to crude oil has been recorded almost parallel to toxicant concentrations. The objectionable odour of the crude oil and the formation of coagulated mucous film over the body and gills were the main factors causing mortality among the experimental fish. The 24, 48, 78 and 96-h TL 50 values have been 3275, 1750, 1650 and 1450 ppm. The corresponding regression coefficients b were –1.8056, –1.5849, –1.6037 and –1.6497.     

Toxicity of distillery wastes to Puntius sophore (HAM.) and Mystus Vittatus (BLOCH) (Pisces,Cyprinidae, Bagridae) Part 3: Bioassay studies and TLm determination

The toxicity of the distillation wastes with low acidity, high turbidity and high organic load to the two fish species is tested by a laboratory test. The threshold value of toxicity is found at a 4 or 7 per cent dilution of wastewater. The statistical analysis of the survival rates has shown that the survival rates are significantly dependent on concentration and the time of exposure, for Puntius sophore also on temperature within the range of 20…34°C. Mystus vittatus proves to be the significantly more resistant species. The maximum permissible concentration of waste in the water ist calculated, too.     

Effect of ammonium jarosite on early life stages of a saltwater fish,Cyprinodon variegatus

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.     

Differential developmental toxicity of naphthoic acid isomers in medaka (Oryzias latipes) embryos

Polycyclic aromatic hydrocarbons (PAHs) are widespread persistent pollutants that readily undergo biotic and abiotic conversion to numerous transformation products in rivers, lakes and estuarine sediments. Here we characterize the developmental toxicity of four PAH transformation products each structural isomers of hydroxynaphthoic acid: 1H2NA, 2H1NA, 2H3NA, and 6H2NA. Medaka fish (Oryzias latipes) embryos and eleutheroembryos were used to determine toxicity. A 96-well micro-plate format was used to establish a robust, statistically significant platform for assessment of early life stages. Individual naphthoic acid isomers demonstrated a rank order of toxicity with 1H2NA > 2H1NA > 2H3NA > 6H2NA being more toxic. Abnormalities of circulatory system were most pronounced including pericardial edema and tube heart. To determine if HNA isomers were AhR ligands, spatial-temporal expression and activity of CYP1A was measured via in vivo EROD assessments. qPCR measurement of CYP1A induction proved different between isomers dosed at respective concentrations affecting 50% of exposed individuals (EC50s). In vitro, all ANH isomers transactivated mouse AhR using a medaka CYP1A promoter specific reporter assay. Circulatory abnormalities followed P450 induction and response was consistent with PAH toxicity. A 96-well micro-plates proved suitable as exposure chambers and provided statistically sound evaluations as well as efficient toxicity screens. Our results demonstrate the use of medaka embryos for toxicity analysis thereby achieving REACH objectives for the reduction of adult animal testing in toxicity evaluations.     

The Uptake of 226Ra by Planktonic Algae under Conditions of Continuous Cultivation

The radium cumulation in Coelastrum cambricum, Scenedesmus obliquus and Microcystis pulverea was studied under conditions of continuous cultivation at constant level of radium in the cultivation medium. The algae were exposed to the concentrations of 30, 300 and 3000 Bq/l ²²⁶Ra in the medium for a period of 14 days. It was found that radium started to cumulate immediately after its addition to the culture just as in the stationary type of cultivation, in the continuous cultivation, however, its content decreased with the length of exposure. This is due to the decreasing part of radium adsorbed on the cell surface. While in green algae the portion of radium incorporated into cells increased with the length of exposure, in blue-green algae up to 90% of radium was bound to the surface or gelatinous capsules of the cells through out the experiment. With the three phytoplankton species used, the highest cumulation of radium (nonwashable part) was recorded in Coelastrum cambricum. A dependence of the radium cumulation on its content in the medium was observed in the species Scenedesmus obliquus.     

Evidence of polycyclic aromatic hydrocarbon (PAH) exposure in fish from the Antarctic peninsula

PAH exposure was assessed in fish from Arthur Harbor, Antarctica and sites remote from human activities by measuring the concentrations of polycyclic aromatic hydrocarbon (PAH) metabolites in bile and PAH in tissues and stomach contents. The highest concentrations of biliary metabolites and tissue PAH were present in fish captured near an Argentine supply ship (Bahia Paraiso) that ran aground in Arthur Harbor in 1989. The presence of biliary PAH metabolites in fish collected near Palmer Station, a small US scientific station in Arthur Harbor, suggests low level exposure to contaminants. However, PAH tissue concentrations in fish from Palmer Station were similar to those from remote sites. Both tissue PAH and metabolite concentrations were low in fish captured at sites remote from human activities. The confirmation of PAH metabolites in the bile of fish from Arthur Harbor is direct evidence that the presence of humans has resulted in Antarctic fish being exposed to petroleum-derived PAH.     

Use of exposure time and life expectancy in models for toxicity to aquatic organisms

The exposure time is a variable which is usually not incorporated into models for toxicity. However, with persistent organic pollutants (POPs) exhibiting a nonspecific mode of action and lipophilic properties this variable can be modeled by the usage of the internal concentrations as a measure of the toxicity with fish. The bioconcentration process with fish is a relatively well understood and predictable process which allows the calculation of the internal lethal concentration. When the exposure time is relatively short the critical internal lethal concentrations are relatively constant for the group of POPs whereaas the LC50 measured in the ambient water is quite variable. When the exposure time is relatively long, results on the measurement of the critical internal concentration with fish over different exposure times has demonstrated that the internal lethal concentration falls with increasing exposure times in a consistent and predictable manner. This reduction in life expectancy can be described in a model which can be used to estimate the critical internal concentration for any exposure time. It also provides information useful in assessing the risk to fish and potentially other species due to the occurrence of residues of POPs in natural aquatic systems. It is suggested that these relationships can be extended to other groups of organisms and chemicals.     

Tolerance measurement and histopathological observations on the gills of Mystus M. vittatus under the toxic stress of the fertilizer NPK

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.     

Toxicity of 1,4-dichlorobenzene in sediments to juvenile polychaete worms

Investigation of sediment contamination associated with a marine sewage outfall in Victoria (BC, Canada) found elevated concentrations of 1,4-dichlorobenzene (1,4-DCB). Juvenile polychaete worm (Neanthes) growth was significantly reduced at or near the outfall, roughly corresponding to elevated 1,4-DCB concentrations. There are few data on 1,4-DCB toxicity to marine organisms and no published literature on its toxicity to benthic marine organisms. To determine whether reduced polychaete growth (measured as dry weight) was due to 1,4-DCB exposure, a laboratory investigation was conducted. Uncontaminated marine sediment was spiked with 1,4-DCB and juvenile Neanthes were exposed in 20-d sublethal toxicity tests. There were no adverse effects on survival at any test concentration; mean survival was 80–100%. Statistically significant decreases in average dry weight only occurred at the highest 1,4-DCB concentration (19,900 μg/kg, dry weight); this represented a 1,4-DCB concentration more than 10 times higher than previously measured at the outfall (1710 μg/kg, dry weight). There were no adverse effects on survival or dry weight at the range of concentrations previously measured in sediments from the vicinity of the outfall.     

Use of exposure time and life expectancy in models for toxicity to aquatic organisms

The exposure time is a variable which is usually not incorporated into models for toxicity. However, with persistent organic pollutants (POPs) exhibiting a nonspecific mode of action and lipophilic properties this variable can be modeled by the usage of the internal concentrations as a measure of the toxicity with fish. The bioconcentration process with fish is a relatively well understood and predictable process which allows the calculation of the internal lethal concentration. When the exposure time is relatively short the critical internal lethal concentrations are relatively constant for the group of POPs whereaas the LC50 measured in the ambient water is quite variable. When the exposure time is relatively long, results on the measurement of the critical internal concentration with fish over different exposure times has demonstrated that the internal lethal concentration falls with increasing exposure times in a consistent and predictable manner. This reduction in life expectancy can be described in a model which can be used to estimate the critical internal concentration for any exposure time. It also provides information useful in assessing the risk to fish and potentially other species due to the occurrence of residues of POPs in natural aquatic systems. It is suggested that these relationships can be extended to other groups of organisms and chemicals.     

Hepatic 7-ethoxyresorufin O-deethylase Activity in eel (Anguilla Anguilla) from The Thames Estuary and Comparisons with other United Kingdom Estuaries

Hepatic microsomal 7-ethoxyresorufin O-deethylase (EROD) activities (indicative of exposure to polycyclic aromatic hydrocarbons (PAHs) and polychlorobiphenyls (PCBs)) were measured in eel Anguilla anguilla from the Thames Estuary. Fish were collected from up to 13 sites during November 1997, May and August 1998 and October 1999. Throughout this period no clear seasonal variation could be identified at every site along the Thames. However, during the summer months, fish sampled from sites in the middle to the upper estuary (Woolwich, Greenhithe and West Thurrock) reported up to 3-fold higher EROD activities compared to sites either at the upper reaches (Richmond and Brentford) at the same time of the year, or fish sampled in winter, along the entire length of the estuary. A laboratory exposure experiment demonstrated a 3-fold elevation of EROD activity 2 days after injection with β-naphthoflavone (β-NF). However, higher levels of activity could be determined in fish sampled from the Weston canal near the Merseyside. The lowest levels of A. anguilla EROD activity were observed in fish sampled from the upper reaches of the River Tamar, Devon, and were comparable to activities determined in fish from the Wear and Humber estuaries. A. anguilla sampled along the Thames, Tyne and Tees estuaries reported between 2.5- and 7-fold higher EROD activities compared to fish collected from the Tamar. These results indicate that a low to moderate induction of A. anguilla CYP1A had occurred (indicative of low to moderate exposure to PAHs and planar PCBs) in fish collected from the Thames, Tyne, Wear, Tees, Humber and Tamar estuaries. However, the highest level of EROD activity was observed in fish from the Weston Canal (Merseyside).     

Fenvalerate and Cypermethrin Induced Changes in the Haematological Parameters of Cyprinus carpio

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.     

A Study on the Effect of Temperature upon the Toxicity of Sodium Pentachlorophenate to the Freshwater Snail Viviparus bengalensis L.

The toxicity of Na-pentachlorophenate to Viviparus bengalensis is investigated by batch tests with daily exchange of medium in the temperature range between 19 °C (February), 27 °C (April), 32 °C (June) and 30 °C (August) at times of exposure between 12 and 96 h. In the range of higher concentrations, pronounced abnormalities in behaviour by secreting mucus and discharging eggs and embryos occur. The LC₅₀ are lowest for all times of exposure at 27 °C, whereas the times of survival with a given concentration are highest at 30 °C. From the LC_{50, 96h, 27°C} = 66 μg/l results a safe concentration of only 47 μg/l Na-pentachlorophenate for Viviparus bengalensis.