Plant-mediated effects of heavy metal pollution on host choice of a grass miner

We studied the effects of heavy metal exposure on host plant choice and performance of the grass miner Chromatomyia milii (Diptera, Agromyzidae). Cadmium decreased plant growth in a dose-dependent way. C. milii preferred the control to the cadmium-exposed plants for feeding and oviposition. Moreover, preference for the control plants increased with increasing cadmium exposure of the alternative choice. Adult and offspring performance decreased with increasing plant cadmium exposure. This suggests that, at least under our laboratory conditions, host choice of C. milii is adaptive under pollution stress. Foliar cadmium concentration increased and the soluble sugar concentration decreased with increasing cadmium exposure. Regression analysis showed that both latter components might be responsible for the decrease in performance of C. milii on cadmium-exposed plants. The protein and amino acid concentration of the leaves, the amount of structural defenses, and water concentration were not affected by the cadmium treatment.     

Distribution of heavy metals in muscle, liver and kidney of northern fur seal (Callorhinus ursinus) caught off Sanriku, Japan and from the Pribilof Islands, Alaska

The concentrations of iron, manganese, zinc, copper, cadmium, and mercury were determined in muscle, liver and kidney of 67 northern fur seals (Callorhinus ursinus) collected off Sanriku, Japan, and from the Pribilof Islands, Alaska. Almost all the elements except cadmium were highest in liver. Cadmium levels in kidney were higher than those in liver and muscle for all animals analyzed. Concentrations of mercury increased significantly with age in muscle, liver and kidney, as did iron levels in muscle and liver and cadmium levels in muscle, while manganese concentrations decreased with age in muscle and kidney. The kidney also showed decreased copper concentration with age. Cadmium concentrations of the northern fur seals in this study were higher than the other otariids, reflecting a predominantly squid diet. Concentrations of manganese and mercury were found to be higher in the fur seals caught off Sanriku than in animals from the Pribilof Islands, while those of zinc and cadmium were found to be lower. Variable concentrations of cadmium might have been attributed to those in seawaters. Discriminant analysis of heavy metal concentrations was used to identify habitat. Sixty-three of 67 animals (94%) were correctly classified using this technique. Heavy-metal concentrations in tissues may provide a useful method to elucidate the primary feeding grounds of fur seals.     

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.     

Protective role of zeolite on short- and long-term lead toxicity in the teleost fish Heteropneustes fossilis.

The high ion-exchange capacity of zeolite (sodium aluminium silicate) enhances the removal of lead from water, thus decreasing its availability to fish. Zeolites are very important in the field of environmental preservation due to the low cost and ecological compatibility. Zeolites can adsorb metallic ions by cation exchange reactions. Continuous exposure of the teleost fish Heteropneustes fossilis to sublethal concentrations of lead nitrate in water solution for short (35 days) and long (120 days) periods decreased both the soluble protein, RNA and glycogen contents in the liver and the body weight, but increased the cholesterol content. The presence of zeolite in the exposure solution decreased all of the adverse effects. In fish exposed to zeolite as feed additive, all the parameters improved in comparison to control fish, indicating that zeolites can be used safely in biological systems.     

Exposure to sublethal concentrations of Zn(II) and Cu(II) changes biochemical parameters in Leporinus obtusidens

The aim of the present study was to assess the effect of the exposure of Leporinus obtusidens (Piava) to zinc and copper on catalase activity in the liver, delta-aminolevulinate dehidratase (delta-ALA-D) activity in liver, muscle, brain and kidney, and thiobarbituric reactive species (TBARS) in brain, muscle and liver. In addition, hematological parameters were measured in blood. The fish were exposed to 10% and 20% of the derived LC(50) values, 2.3 and 4.6 mg Zn l(-1) and 0.02 and 0.04 mg Cu l(-1), and sampled on days 30 and 45. Exposure to Zn(II) and Cu(II) decreased hematological parameters and also delta-ALA-D activity mainly in liver and kidney at all concentrations tested. Liver catalase activity increased after zinc or copper exposure at all concentrations and exposure times tested. Thiobarbituric reactive substances (TBARS) increased in the brain and liver of the fish exposed to zinc(II) for 45 days at both metal concentrations. In muscle, zinc(II) increased TBARS production at both exposure times and concentrations tested. Copper(II) exposure reduced the TBARS levels in liver at both concentrations and times tested. In brain, there was a decrease in TBARS levels only after 45 days of exposure. In muscle, this decrease was observed after 30 days of exposure at both concentrations. Although zinc and copper are required as microelements in the cells, our results showed that the sublethal concentrations of these metals can change biochemical parameters which may alter normal cellular function. These results pointed out the differential sensitivity of fish tissues to essential, but also toxic and environmentally relevant metals. The alterations of distinct biochemical parameters in fish tissues certainly contribute to the toxicity of Zn and Cu, and are of importance for an area that has been growing and has still been poorly explored in the literature.     

Effects of four rice herbicides on some metabolic and toxicology parameters of teleost fish (Leporinus obtusidens)

Effects of different herbicides on acetylcholinesterase (AChE), catalase and TBARS formation in teleost fish (Leporinus obtusidens) were studied. Fish were exposed during 30 days at concentrations of herbicides used in rice field. AChE activity in the brain decreased significantly after exposure to the herbicides clomazone and quinclorac. However, AChE activity increased significantly in muscle tissue after exposure to clomazone, propanil and metsulfuron methyl. Fish exposed to quinclorac, propanil and metsulfuron methyl showed TBARS decreased levels in brain and muscle tissues. However, TBARS and catalase activity increased in liver tissue after clomazone and propanil exposure. This study pointed out long-term effects on AChE activity, oxidative stress and antioxidant enzyme catalase in tissues of L. obtusidens after exposure to environmentally relevant concentrations of rice field herbicides. These parameters have been used to monitor fish toxicity in rice field system.     

Variation of zinc and copper in metallothionein-like protein in killifish (Oryzias latipes) exposed to cadmium

Killifish (Oryzias latipes) were exposed for 0, 24, 48 and 168 hours to cadmium solution. The hepatic cytoplasm was fractionated by using Sephadex G-75 and the content of zinc, copper and cadmium in the fractions was measured. Cadmium content in the metallothionein fraction increased with increase of exposure time. Zinc content in the metallothionein fraction was reduced at early exposure time and increased after prolonged exposure. Copper content in the metallothionein fraction was unchanged. It is shown that zinc bound to thionein in the liver is partially replaced by cadmium and that at least two isomers of metallothionein occur in this fish.     

Metal bioavailability and toxicity to fish in low-alkalinity lakes: A critical review

Fish in low-alkalinity lakes having pH of 6.0-6.5 or less often have higher body or tissue burdens of mercury, cadmium, and lead than do fish in nearby lakes with higher pH. The greater bioaccumulation of these metals in such waters seems to result partly from the greater aqueous abundances of biologically available forms (CH(3) Hg(+), Cd(2+), and Pb(2+)) at low pH. In addition, the low concentrations of aqueous calcium in low-alkalinity lakes increase the permeability of biological membranes to these metals, which in fish may cause greater uptake from both water and food. Fish exposed to aqueous inorganic aluminum in the laboratory and field accumulate the metal in and on the epithelial cells of the gills; however, there is little accumulation of aluminum in the blood or internal organs. In low-pH water, both sublethal and lethal toxicity of aluminum has been clearly demonstrated in both laboratory and field studies at environmental concentrations. In contrast, recently measured aqueous concentrations of total mercury, methylmercury, cadmium, and lead in low-alkalinity lakes are much lower than the aqueous concentrations known to cause acute or chronic toxicity in fish, although the vast majority of toxicological research has involved waters with much higher ionic strength than that in low-alkalinity lakes. Additional work with fish is needed to better assess (1) the toxicity of aqueous metals in low-alkalinity waters, and (2) the toxicological significance of dietary methylmercury and cadmium.     

Metabolic rate and uptake and loss of cadmium from food by the fish Noemacheilus barbatulus L. (stone loach)

Fish, Noemacheilus barbatulus (stone loach), of different body weights were used to study rates of uptake and loss of cadmium during and after dietary exposure. Fish were kept singly in a continuous-flow system, and fed tubificid worms. The worms had a range of cadmium levels, but all levels were below that needed to cause acute lethal toxicity in the fish. Body weight affected both the maintenance ration and the amount of food consumed ad libitum, but the exponent for body weight (0.78+/-0.04), relating body weight to food consumption, was unaffected by either temperature or the size of feeding ration. The cadmium content of the worms did not affect the size of the maintenance ration. Metal burden in fish changed rapidly both during and after exposure. After exposure, the cadmium burden of starved fish usually declined more rapidly than in fed fish. A 58-fold increase in cadmium content in the food produced a 28% increase of body burden in the fish, and there was no evidence for biomagnification. Maintenance ration and ration ad libitum and rates of uptake and loss of cadmium increased with temperature within the range 8-18 degrees C, but exposure to cadmium at 16 degrees C yielded a higher asymptotic body burden than either 8 degrees C or 18 degrees C. Rate constants for loss of cadmium after exposure appear to be lower than for loss during exposure. Rates of uptake and loss of cadmium vary with metabolic rate. A maximum in the rate of oxygen consumption was measured at 16 degrees C, above which the rate dropped, presumably due to stress. The exponent for body weight was unaffected by activity or temperature. Body weight of fish appeared to affect both the rates of uptake and loss of cadmium, and feeding rations and respiration to the same extent: body weight exponents were not dissimilar.     

Effect of cadmium and zinc on intestinal absorption of xylose and tryptophan in the fresh water teleost fish, Heteropneustesfossilis

The effect of cadmium and of zinc on the rate of uptake of a pentose sugar xylose and an aminoacid tryptophan by the intestine of a teleost fish, $\text{Heteropneustes}$$\text{fossilis}$ was studied under two experimental conditions. In the first, four concentrations of cadmium or zinc (1.0 mM, 0.1 mM, 0.01 mM and 0.001 mM) mixed with the nutrient solution were filled in the intestinal sacs, and the rate of absorption was recorded after 1 h at 23°C. In the second experiment fish were exposed by bath to a sublethal concentration of cadmium (0.26 mg/1) or zinc (4 mg/1) for 15 and 30 days and the rate of absorption of the two nutrients was measured. The activity of intestinal Na⁺, K⁺ activated adenosine triphosphatase was also assayed. The two heavy metals at all the four concentrations decreased the rate of intestinal transport of nutrients. Increase in the concentration of each of the heavy metals decreased the uptake of nutrients, but the decreases were not linear. The rate of intestinal absorption of the two nutrients was also reduced by exposure of fish to the heavy metals $\text{in}$$\text{vivo}$. The activity of Na⁺, K⁺ ATPase decreased $\text{in}$$\text{vitro}$ with all four concentrations of cadmium and zinc and was diminished in fish exposed for 15 and 30 days. Of the two heavy metals, cadmium was more effective in reducing the rate of transport of xylose and tryptophan.     

Sublethal Cd-induced cellular damage and metabolic changes in the freshwater crab Sinopotamon henanense

To explore whether sublethal cadmium (Cd) exposure causes branchial cellular damages and affects the metabolic activity in brachyuran crustaceans, the freshwater crab Sinopotamon henanense was exposed to 0.71, 1.43, and 2.86 mg/L Cd²⁺ for 3 weeks. Gill morphology, metabolic activity (activities of isocitrate dehydrogenase (IDH), cytochrome c oxidase (CCO) and lactate dehydrogenase (LDH), mRNA expression of CCO active subunit 1 (cco-1) and ldh, as well as ATP levels) in crab muscle were investigated. The results showed that sublethal Cd exposure caused profound morphological damages in the gills. The branchial epithelial cells were disorganized and vacuolized. Ultrastructurally, a decrease in number of apical microvilli, vacuolized mitochondria, and condensed chromatin were observed in gill epithelial cells. Correspondingly, the Cd exposure also induced downregulations of cco-1 and ldh mRNA expression and reduced activities of IDH, CCO, and LDH, in accordance with the lower ATP level in crab muscle. These results led to the conclusion that gill damage caused by sublethal Cd exposure could lead to an impairment of oxygen uptake of S. henanense, and the inhibition of metabolic activity decreases the oxygen demand of the crab and assists them to survive under the condition of lower oxygen availability. These effects add to our understanding on toxic effects of Cd and survival management of S. henanense subchronically exposed to sublethal Cd.     

Effects of sublethal exposure to a pesticide on levels of energetic compounds in Anguilla anguilla.

Abstract

The effect of two sublethal fenitrothion concentrations (0.02 and 0.04 mg/L) on the energy metabolism of the european eel Anguilla anguilla and its recovery from intoxication was investigated. Analysis of various parameters such as glycogen, proteins and total lipids was made on liver and muscle eel tissues after 2, 8, 12, 24, 32, 48, 56, 72 and 96 hr of fenitrothion (0,0‐dimethyl 0–3‐methyl‐4‐nitrophenyl phosphorothioate) exposure. Subsequently, the fish were allowed recovery periods of 8, 12, 24, 48, 72, 96, 144 and 192 hr in clean water, and the same parameters were again evaluated. The results obtained during the exposure to the pesticide as well as during the recovery phase were used to calculate the caloric content in both tissues of A. anguilla. A reduction in energy reserves in the selected tissues was observed after exposure to both fenitrothion concentrations and the caloric content in those animals was lower than in the controls. Most of the metabolic disorders did not persist after allowing recovery in clean water during a week.     

Acute toxicity, uptake and clearance of diazinon by the European eel, Anguilla anguilla (L.).

The toxicity, accumulation, and elimination of diazinon were investigated for the european eel, Anguilla anguilla. The 24, 48, 72 and 96-h median lethal concentrations (LC50) were 0.16, 0.11, 0.09 and 0.08 mg/L, respectively. Fish exposed to sublethal concentration (0.042 mg/L) accumulated diazinon in liver and muscle tissues. Bioconcentration factors (BCF) of diazinon were 1850 in liver, and 775 in muscle over the 96-h exposure period. Upon removal from diazinon containing water the contaminated fish rapidly eliminated diazinon. The excretion rate constants of this insecticide were 0.108 h-1 for liver and 0.016 h-1 for muscle. Diazinon half-lives were 16.6 and 33.2 hours for liver and muscle, respectively.     

Response of Cyprinus carpio (Linn) to sublethal concentration of cypermethrin: alterations in protein metabolic profiles

Freshwater fish, Cyprinus carpio were exposed to sublethal concentration (1.2 microg l(-1)) of cypermethrin for 6, 12, 24 and 48 h to analyze various parameters of protein metabolism in functionally different tissues. Total, structural and soluble proteins showed decrement; where as free amino acids and the activities of protease, aspartate aminotransferase and alanine aminotransferase significantly increased in cypermethrin exposed fish. Interestingly, ammonia content decreased but urea and glutamine increased at all periods of exposure. It was also observed that alterations steadily increased with the period of exposure and exhibited tissue specificity. Thus variation in the protein metabolism of the fish exposed to cypermethrin indicates its toxic effect on the cellular metabolism thereby leading to impaired protein synthetic machinery.     

Biomarkers assessment in juvenile Cyprinus carpio exposed to waterborne cadmium

The impact of long-term exposure to waterborne cadmium (Cd) on Cyprinus carpio was evaluated through changes of selected parameters considered as biomarkers of toxicity. Fish were exposed to 1.6 mg l(-1) Cd for 14 days and then transferred to Cd-free water for 19 days. The measured parameters were gill ATPases, brain acetylcholinesterase (AchE), liver glutamate oxaloacetate (GOT) and glutamate pyruvate (GPT) transaminases, muscle water content, and protein content of liver, gills and brain. Condition factor and liver somatic index were also calculated. Branchial ATPase activities were impaired in a dissimilar way: the (Na(+),K(+))-ATPases were inhibited by approximately 30%, while the Mg(2+)-ATPase was significantly activated by 70%. Brain AchE showed no changes after Cd exposure. Both liver GOT and GPT activities were increased by the metal by 63 and 98%. Water content of the skeletal muscle showed no significant alterations. After the 19-day recovery phase, changes in the Mg(2+)-ATPase and GPT were reversed to values similar to controls, but the Cd exposure resulted in an irreversible alteration in GOT activity. Results indicate that the sublethal Cd concentrations are stressful to carp, particularly with reference to branchial enzymes which may disrupt the osmotic and ionic balance of the animals.     

Toxicological response of silver catfish (Rhamdia quelen) after acute exposure to a commercial insecticide containing thiamethoxam

Abstract

This study assessed the hematological, enzymatic and osmoregulatory responses of silver catfish (Rhamdia quelen) exposed to sublethal concentrations (1.125 and 3.750?µg/L) of a commercial thiamethoxam-containing insecticide used on rice crops. Groups of 6 fish per tank (in triplicate, n?=?3, total 54 fish) were exposed for up to 96?h to different concentrations of the compound. After this period, fish were placed in clean water for 48?h. Two fish from each tank (6 per treatment) that had been exposed to the insecticide for 24?h were anesthetized with eugenol and blood was collected to evaluate hematological and biochemical parameters. Blood, liver and muscle were collected for determination of metabolic parameters, plasma cortisol, Cl^-, Na⁺ and K⁺ levels and H⁺-ATPase and Na⁺/K⁺-ATPase activity in the gill. H⁺-ATPase activity was higher in fish exposed to 1.125?µg/L insecticide at 24?h compared to control (0.0?µg/L). Differences in cortisol levels were evidenced throughout the experimental period. These results indicated that exposure to the insecticide changed the hematological, biochemical and metabolic profile of the animals, suggesting concern about environmental safety. Therefore, we discourage the use of this pesticide in areas that come into contact with water bodies inhabited by fish.     

Metabolic effects of diazinon on the European eel

Abstract

Eels were exposed to a sublethal diazinon concentration of 0.042 mg/L for exposure times of 6, 24, 48, 72 and 96 hours. Biochemical analyses of blood composition, such as plasma glucose, total plasma cholesterol and triglycerides, plasma lactate, plasma urea and uric acid, showed significant differences between treated and control animals. Plasma glucose and lactate increased after 6 hours exposure to the insecticide. Plasma cholesterol and triglycerides content decreased during 96 hours treatment. Urea levels increased at 72 hours while uric acid content decreased significantly at 24, 72 and 96 hours exposure to the pesticide.

The observed effects of diazinon on eel metabolism suggested that the treated fish was faced with a serious metabolic crisis, and the fish looked for alternative methods of metabolism to overcome the toxic stress.     

Cytotoxicity,redox and immune status in African catfish,Clarias gariepinus (Burchell, 1822) exposed to bisphenol A (BPA) and its analogues

The objective of the study was to determine the comparative toxicities and immune dysfunction in the African catfish, Clarias gariepinus, exposed to bisphenol A (BPA) and its two analogues: bisphenol AP (BPAP) and bisphenol P (BPP). Juveniles of C. gariepinus were exposed to sublethal concentrations (70 and 140 μg/L) of BPA, BPAP and BPP for 7, 14 or 21 days after which various endpoints which are indicative of cytotoxicity, oxidative stress and haematological and innate immune parameters were determined in the liver homogenates or blood plasma. The exposure of C. gariepinus to BPA and its analogues caused significant increased activities of lactate dehydrogenase, catalase and superoxide dismutase. The exposed fish had increased levels of DNA fragmentation, lipid peroxidation, white blood cells, nitric oxide and respiratory burst, while the red blood cell counts and the percentage packed cell volume decreased significantly in the exposed fish compared to control. The toxic effects elicited by the bisphenols were both concentration- and duration-dependent. Generally, BPA exerted the most toxic effects on the fish, followed by BPAP, while BPP exerted the least toxic effects to C. gariepinus. Summarily, the findings indicated that BPA and its two analogues studied in the research are capable of causing cytotoxicity, oxidative stress and immune dysfunction in C. gariepinus.

     

Heavy metal (Cd, Cr, Cu, Hg, Pb, Zn) concentrations in seven fish species in relation to fish size and location along the Yangtze River

Purpose

The objective of this paper is to assess the regulation of the accumulation of heavy metals in the aquatic environment and different fish species.

Methods

Water and fish samples were collected from upper to lower reaches of the Yangtze River. The heavy metal (Cd, Cr, Cu, Hg, Pb, Zn) concentrations in the muscle tissue of seven fishes were measured. Additionally, the relationships between heavy metal concentrations in fish tissue and fish size (length and weight), condition factor, water layer distribution, and trophic level were investigated.

Results

Metal concentrations (milligrams per kilogram wet weight) were found to be distributed differently among different fish species. The highest concentrations of Cu (1.22?mg/kg) and Zn (7.55?mg/kg) were measured in Pelteobagrus fulvidraco, the highest concentrations of Cd (0.115?mg/kg) and Hg (0.0304?mg/kg) were measured in Silurus asotus, and the highest concentrations of Pb (0.811?mg/kg) and Cr (0.239?mg/kg) were measured in Carassius auratus and Cyprinus carpio. A positive relationship was found between fish size and metal level in most cases. The variance of the relationships may be the result of differences in habitat, swimming behavior, and metabolic activity. In this study, fishes living in the lower water layer and river bottom had higher metals concentrations than in upper and middle layers. Benthic carnivorous and euryphagous fish had higher metals concentrations than phytoplankton and herbivorous fish. Generally, fish caught from the lower reach had higher metals concentrations than those from the upper reach.

Conclusions

Cadmium and lead concentrations in several fishes exceeded the permissible food consumption limits, this should be considered to be an important warning signal.     

Comparison of arsenate and cadmium toxicity in a freshwater amphipod (Gammarus pulex)

Cadmium is largely documented on freshwater organisms while arsenic, especially arsenate, is rarely studied. The kinetic of the LC50s values for both metals was realized on Gammarus pulex. Physiological [i.e. metal concentration in body tissues, bioconcentration factor (BCF)] effects and behavioural responses (via pleopods beats) were investigated after 240-h exposure. Arsenate LC50 value was 100 fold higher than Cd-LC50 value after 240-h exposure, while concentrations in gammarids were similar for both metals at their respective LC50s. BCF decreased with increasing cadmium concentration while BCF remained stable with increasing arsenate concentration. Moreover, BCF was between 148 and 344 times lower for arsenate than cadmium. A significant hypoventilation was observed for cadmium concentrations exceeding or close to the 240h-LC50(Cd), while gammarids hyperventilated for the lowest arsenate concentrations and hypoventilated for the highest arsenate concentrations. We discussed the relationships between potential action mechanisms of these two metals and observed results.