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Use of histopathology and elemental accumulation in different organs of two benthophagous fish species as indicators of river pollution
Abstract
The bottom feeding fish species have a good potential to be used for assessments of pollution, as they are under pressure from pollutants from both water and sediments. In this study, the level of similarity of histopathological responses to pollution in gills and liver between barbel (Barbus barbus) and sterlet (Acipenser ruthenus) from the Danube River was assessed, and compared with elemental concentrations in their gills, liver, and muscle. Results indicate that the detected metal concentrations were likely cause of different tissue responses in gills and liver of the two investigated fish species. Statistical analysis indicated a clear differentiation of the two species based on elemental concentrations and the level of histopathological changes in gills and liver. Metal concentrations exceeded maximum acceptable concentrations in a number of analyzed specimens, which indicates the importance of this type of monitoring. Results indicate that barbel is a better indicator for specific, rather narrow sites, whereas sterlet is a better indicator of larger (longer) water current segments. Obtained information could be of importance for both scientists and fishery and water management authorities working on the development of water monitoring programs. © 2014 Wiley Periodicals, Inc. Environ Toxicol, 2014.
... Many authors pointed out that the highest concentrations of Hg are expected in the muscle tissue of piscivorous species (Zrnčić et al. 2013;Jovičić et al. 2015;Nikolić et al. 2021a). On the other hand, due to pressure from both water and sediment contaminants, bottom-feeding fish species have good potential to be used to assess pollution (Rašković et al. 2015). The most used fish species in bioindication of water PTE pollution in Serbia is S. glanis, which confirm the statement of Squardone et al. (2013) that this species can adequately reflect ambient element concentrations. ...
... If the ten-year research period is taken into account, over years, there was no trend of increase or decrease in the number of individuals with concentrations of PTEs above the MPCs ("hot spots") in Danube River. Rašković et al. (2015) found concentrations of Hg and Ni above MPCs in one or two fish individuals, while in other studies, concentrations were elevated in almost all fish individuals. In studies published in 2019 and later (Subotić et al. 2019(Subotić et al. , 2021Kostić-Vuković et al. 2021), there were no concentrations of PTEs above MPCs. ...
... Several studies in Serbia dealt with histopathological alterations in fish tissues, and the use of comet assay and micronucleus as biomarkers. A higher level of histopathological alterations was found in the gills of B. barbus and A. ruthenus (Rašković et al. 2015), and a lower one in the gills of S. lucioperca (Nikolić et al. 2021b) and A. brama (Kostić-Vuković et al. 2021) was detected. Rašković et al. (2018) determined a higher level of histopathological alterations as a result of mine tailing accident in Korenita River and anthropogenic activities in Međuvršje Reservoir. ...
In the first review of potentially toxic elements (PTEs) in fish in water ecosystems in Serbia, 40 studies related to fish contamination with PTEs were identified and evaluated. Studies of concentrations of PTEs in fish tissues covered 28 ecosystems (108 localities). The main studied river ecosystems were the Danube and the Sava, and the Međuvršje reservoir was the most studied standing water ecosystem. Among the most studied fish species were catfish (Silurus glanis), followed by pikeperch (Sander lucioperca), bream (Abramis brama), carp (Cyprinus carpio), and barbel (Barbus barbus). There were 48 “hot spot” sampling sites where concentrations of Hg, Cd, Pb, As, Ni, Fe, and/or Cu exceeded the maximum permitted concentrations (MPCs) prescribed by legislation. Elevated concentrations of these elements were the most detected in fish species sampled in the Danube, Sava, and rivers belonging to the Velika Morava basin. Hg concentrations were the most common above MPC in muscle tissue of species sampled from the Danube and Sava rivers. On the other hand, we can single out the species Vimba bream (Vimba vimba), sampled in Danube River in Zemun near Belgrade, as the safest species for human consumption due to the largest number of elements in fish meat below detection limits. Finally, having in mind all the criteria prescribed by U.S. EPA (2000), we identify and recommend two predatory fish species pikeperch (S. lucioperca) and catfish (S. glanis), and bottom-feeding fish species barbel (B. barbus) as bioindicators of PTEs contamination in Serbian waters.
... Histopathological alterations in various fish organs have a pronounced value in aquatic toxicology [3] and are widely used in the monitoring of aquatic pollution [4][5][6]. Among them, gills are particularly useful in environmental monitoring given that they have a large surface area, thin epithelium, are in direct contact with water and are generally considered to be among most affected organs by waterborne compounds [7,8]. ...
... Among them, gills are particularly useful in environmental monitoring given that they have a large surface area, thin epithelium, are in direct contact with water and are generally considered to be among most affected organs by waterborne compounds [7,8]. So far, many studies have assessed gill structural changes in response to waterborne pollutants and environmental pollution, and have recognized them as valuable biomarkers of water pollution [3,5,[9][10][11]. ...
... Histopathological alterations are determined as reliable biomarkers in differentiating levels of pollution between different aquatic ecosystems [4,5,12,13]. However, there are very few studies which account for seasonal differences in gill reactions and which analyze the differences in gill reaction to seasonal variations in water quality. ...
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The study highlights the utility of using histopathological alterations in gills of an indigenous fish species (common bream) in differentiating seasonal variations in water quality. The methodology displayed in this study can be used to obtain more compelling and comprehensive environmental monitoring programs.
Abstract
Histopathological alterations in various fish organs have a pronounced value in aquatic toxicology and are widely used in environmental monitoring. The aim of this study was to evaluate whether histopathological alterations in fish gills can discriminate seasonal variations in environmental conditions within the same aquatic ecosystem, and if so, which alterations contributed the most to seasonal differentiation. Microscopic examination of common bream Abramis brama gills displayed various alterations in gill structure, including epithelial hypertrophy, hyperplasia, mucous and chloride cell alterations, epithelial lifting, necrosis, hyperemia and aneurism. These alterations were subsequently quantified by a semi-quantitative analysis in order to detect differences in the intensity of the mentioned alterations. Epithelial hypertrophy, hyperplasia, epithelial lifting and necrosis varied significantly between seasons with only necrosis being significantly higher in the first season. Discriminant canonical analysis displayed that epithelial hyperplasia, mucous cell alterations, epithelial lifting and necrosis contributed the most to discrimination between seasons. Overall, this study demonstrates that histopathological biomarkers in fish gills can be used in discriminating seasonal variations in water quality within the same aquatic ecosystem.
... The staining methodology was the one known in the literature. The larval samples were processed by the Hematoxylin Eosin (H.E.) staining method, a simple method which reveals the cytoarchitecture of changes in tissues and organs (e.g., respiratory system, digestive tract, liver, kidney, muscle, etc) (6,29). ...
... The methods for determining the effects of acute toxicity are intended to highlight changes in the anatomical and ethological development of the developmental stages, and in particular fish larvae (2,6,14,17,27,29,34,38). Tests performed on fish larvae are chosen due to the easy availability of biological material, the advan-tages of the relatively low cost of materials needed to carry out the tests and especially the short period of performance, thus being able to perform a large number of repetitions of tests, increasing the reliability of statistical results, and interpretations (1,9,12,15,20,27,38). ...
... This study could also be considered as having strengths. For example, the presence of the mentioned behavioral and cytohistological changes (considered critical control points, practically identical to those found in zebrafish), identified for the early stages of sturgeons, support the results obtained by us and consider the sturgeons as a possible new species, fish that could be added to fish species already recognized and accepted internationally for acute environmental toxicology tests (2,3,29,31). The use of juvenile forms of Acipenser ruthenus is beneficial because fish embryos and larvae are exempt from animal protection laws (8). ...
Methods for identifying toxicity to fish larvae can detect the types of acute and/or lethal toxicity of different chemical matrices. The study aimed the cytohistological confirmation of our anterior published study and to identify, upon exposure to lead acetate solutions, the main changes in the architecture of the organs and tissues (vitellus and intestine, liver, kidney, skin, muscles, and heart) as a comparison with the main obtained indicators. The study used two-day-old hatched-free embryos and the samples were divided into groups A and B. After acclimatization period, free larvae were inserted and exposed to decreasing soluble lead solutions as follows: 50 individuals/aquarium, total: 100 larvae/con-
-1 -1 centration: E1-A/E1-B=400 µgL ;E2-A/E2-B=200 µgL ;-1 -1 E3-A/E3-B=100 µgL ; E4 A/E4-B=50 µgL . The control group consisted of 100 vigorous larvae. Acipenser ruthenus larvae were monitored by direct observation at baseline, then at 12, 24, 48, 72, and 96 hours. The first dead larvae were detected after 12 hours of lead exposure, with the tip at an interval of 72-96 hours. Statistics revealed a significant association between the influence* of lead on the parameters of length ( p<0.05) and ** *** weight ( p=0.01; p<0.01) and the number of dead larvae at the same concentration, which statistically demonstrates the detrimental activity of lead in water. Cytohistological architecture confirmed the morphological changes observed on the larvae exposed to lead toxicity, with the signaling of significant cytoarchitectural changes especially for the high concentrations used, (E1A/1B = 400 ppm and E2A/2B = 200 ppm).
... В то же время установлено , что на накопление тяжелых металлов в тканях осетровых влияет их концентрация в донных отложениях и кормовых объектах рыб. Отечественными и зарубежными исследователями (Попов и др., 2014;Rašković et al., 2015) при изучении распределения тяжелых металлов в органах и тканях осетровых рыб анализируются различные части организма рыб, в том числе и не употребляемые в пищу (печень, почки), при этом не исследуются части скелета (хорда), потребляемые населением в качестве пищевых продуктов. ...
... По данным исследователей Rašković et al., 2015) для стерляди определена строгая дифференциация накопления ТМ в тканях: максимальные концентрации Hg отмечают в печени и мышцах -0,730 и 0,630 мг/кг соответственно, минимальные в жабрах -0,006, при этом относительно высокий уровень определяют для Cd, значения которого могут достигать в печени 2,862 мг/кг, в мышечной ткани -0,090, в жабрах -0,147 мг/кг Rašković et al., 2015). Биоаккумуляция ТМ дифференцирована в зависимости от участка водотока, где обитала рыба. ...
... По данным исследователей Rašković et al., 2015) для стерляди определена строгая дифференциация накопления ТМ в тканях: максимальные концентрации Hg отмечают в печени и мышцах -0,730 и 0,630 мг/кг соответственно, минимальные в жабрах -0,006, при этом относительно высокий уровень определяют для Cd, значения которого могут достигать в печени 2,862 мг/кг, в мышечной ткани -0,090, в жабрах -0,147 мг/кг Rašković et al., 2015). Биоаккумуляция ТМ дифференцирована в зависимости от участка водотока, где обитала рыба. ...
For assessing the possibility of using sterlet as a species-bioindicator of heavy metals' contamination in the bottom sediments, a study has been conducted on the distribution and accumulation of these pollutants in the fish body. The patterns of distribution of heavy metals (mercury, cadmium, lead) in the gills, muscles, liver and axial skeleton (chord) of sterlet living in the lower reaches of the Irtysh River have been investigated. The coefficient of biological accumulation in comparison with bottom sediments has been calculated, and heavy metal concentrations have been compared with allowable levels of these toxicants for raw fish. The concentrations of heavy metals (HM) have been determined by the atomic adsorption method. The maximum have been noted for lead, and among the analyzed organs and tissues, its greatest value are in the gills. The rows of HM distribution are as follows:
Pb – gills > liver > muscles > skeleton, Hg – skeleton > gills > liver > muscles, Cd – gills > skeleton > liver > muscles. A statistically significant difference in distribution in the organs and tissues of fish is established only for Hg. Any statistically significant correlation between the distribution of the HM and the weight and size of the fish is not found. A comparative analysis of HM concentrations and sanitary-epidemiological regulations has established that Hg content in sterlet organs does not exceed the permissible level, for Cd in the gills and skeleton an excess of the permissible level is 25 and 9 %, respectively. For Pb in the body of sterlet, an excess of the permissible level in the gills is
48 %. It has been established that TM accumulation in the body of sterlet when compared with bottom sediments prevails over their elimination (> 1) for Cd in the gills, skeleton and liver, for Hg – in the skeleton and for Pb – in the gills. In other cases, the biological accumulation coefficient in the body of sterlet is < 1. The HM distribution for the fish organism and BS has a statistically significant, high direct correlation (RS = 0.95, p < 0.001), thereby we recommend using sterlet as a bioindicator of heavy metals' contamination in the bottom sediments.
... In sturgeons lead and other aquatic pollutants certainly accumulate Raskovic et al., 2015;Subotic et al., 2013) affecting the spermatozoa quality (Linhartova et al., 2015) or generating adverse behavioral changes (Vardy et al., 2014;Wang et al., 2014). ...
... In this aim, in the last decade, studies on this topic were largely diversified, including here different species of sterlet sturgeon, bringing useful information, primarily related http://www.aloki.hu • ISSN 1589 (Raskovic et al., 2015;Linhartova et al., 2015). We observed that the acute toxicity effects of miscellaneous sources, such as heavy metals (in our case), but also effluents, contaminants etc., is highlighted in the registered anatomical and ethological changes of sturgeon early stages Little et al., 2012). ...
... We observed that the acute toxicity effects of miscellaneous sources, such as heavy metals (in our case), but also effluents, contaminants etc., is highlighted in the registered anatomical and ethological changes of sturgeon early stages Little et al., 2012). This is noteworthy, as it is a strong motivation why these fish categories are used in recent pollution hazard and risk assessments including here sturgeons (Vardy et al., 2014;Raskovic et al., 2015). ...
The objective of the study was to devise a 96 h test of sterlet embryos (Acipenser ruthenus) in order to evaluate if this species is suitable for water pollution investigation as an evaluation tool. Replicate concentrations of lead acetate were selected from 400, 200, 100 and 50 µgL-1. Each mirroraquarium was filled with 10 L of lead acetate dilutions, excluding the control, the free sterlet embryos were inserted as follows: 50 / aquarium, i.e. 100 / concentration and control group). The fish were examined at time 0, then at: 12, 24, 48, 72 and 96 hours, every change in behavior or in the body somatic was statistically analyzed, according to ANOVA (significant when p < 0.05, or less). Evaluation revealed significant connection among the embryos length (p < 0.05), weight (p = 0.01; p < 0.01) and the dead embryos proved the deleterious feature of lead at 400 and 200 µgL-1. The main critical points were: the delayed resorption of the yolk sac; deformed tail; undeveloped eyes; massive haemorrhages; atypical / altered pigmentation and exitus observed at 12 h. Although A. ruthenus is not considered as a standard subject in the pollution assays, it was observed that, changes can be applied for early fish stages as a parallel to other accepted tests
... According to the results, the highest histopathological score was found in the gill, followed by the liver and gonad. Similar results were obtained by Rašković et al. [48] in a work developed with Barbus barbus from the Danube River, ...
... According to the results, the highest histopathological score was found in the gill, followed by the liver and gonad. Similar results were obtained by Rašković et al. [48] in a work developed with Barbus barbus from the Danube River, where the metal concentrations exceeded the maximum acceptable, as well as by Javed [4] at the Satha canal water, India, with Channa punctatus exposed to industrial effluents with metals concentrations exceeding the permissible limits. Given that the gill is the organ responsible for ion exchanges with the environment, the histopathological changes could be interpreted as a defense mechanism to increase the distance that heavy metals dissolved in water must diffuse across to reach the bloodstream. ...
The Vilariça River was restored in order to improve the fish habitat due to the construction of dams. However, due to the pressure that agriculture exerts on water resources, it is crucial to evaluate its consequences on fish health from a histological perspective. The gonad histopathological changes of two cyprinid species were assessed microscopically and evaluated with semi-quantitative analysis. Histopathological changes in the gonad, gill, and liver were used as biomarkers in the determination of the Integrated Biomarker Response (IBR), as well as to evaluate the histopathological scores between seasons. The observation of the gonad histopathological changes showed that interstitial fibrosis and macrophage aggregates were present exclusively in the Summer and more prevalent in males of large size. In addition, the histopathological scores of the three organs were higher in the Summer. In terms of the severity degree, 98% and 68% of the fish showed pronounced and severe histopathological changes in the gill and liver, respectively, while 28% of the fish showed slight histopathological changes in the gonad. The IBR showed higher values in the Summer and in the middle stream and downstream, which is in agreement with the metal concentrations. Thus, this work showed a relationship between the anomalies present in the fish organs and the quality of the water (classified as polluted). Therefore, minimization measures are presented, such as improving the irrigation methods, preserving the vegetation cover; promoting reforestation in degraded and burned areas; and improving the riparian vegetation.
... In addition, Kostić et al. [19] argued that the sinusoidal congestion blocks blood from the hepatic artery and the interbiliary portal vein, which has to pass through the sinusoids on its way to the central vein. To reach the central vein, the blood needs to be pumped harder, and this can explain the presence of fibrosis in the periportal and portal areas e.g., [48]. This histopathological change, frequently observed in field studies, has been suggested to be a chronic response to chemical injury [17]. ...
... The authors attributed the presence of fat vacuoles to a general failure of lipid metabolism that arises from a decrease in the utilization of energy reserves or pathological synthesis, i.e., this condition is not a result of the uptake of abundant lipid precursors but is a problem of removing the fat from the hepatocytes. Degenerative vacuolization has also been reported in Barbus barbus [48] and other fish species living in contaminated areas [17,47,52]. ...
Histopathology has been used as a very useful tool to provide information on the severity of tissue damage, injuries, and organ functionality. Thus, this work aimed to assess whether seasonal variations (summer and winter) in water quality had consequences on the liver histology of Iberian barbel (Luciobarbus bocagei) and Douro nase (Pseudochondrostoma duriense). The research was carried out in the Vilariça River, a tributary of the Sabor River in Portugal, which is used as spawning grounds by these endemic cyprinids. The liver histopathological changes, assessed through a semi-quantitative system, allowed the identification of 13 histopathological changes located in the hepatic parenchyma, bile duct, and blood vessels. The histopathological changes with a higher prevalence in both species were vacuolization of hepatocytes, endothelial rupture, necrosis, fibrosis, and degenerative vacuolization. The results showed that the severity degree of liver histological alterations ranged between moderate and severe, and the major severity degree was observed in L. bocagei, in the summer season, and at the sampling points located in the downstream and middle stream. The canonical analysis indicated that the exposure of fish to metals may increase the potential risk of liver damage. Thus, in the summer, the high concentrations of Fe, Cu, Zn, As, and Mn justified the prevalence of the biliary duct epithelial detachment, in both species, and the hyperplasia of biliary epithelium, in L. bocagei. In the winter, the high TSS and Cd, Ni, and Cr concentrations justified the prevalence of congestion of blood vessels and degenerative vacuolization in both species. The higher hepatosomatic index of fish caught in the winter was due to the high presence of degenerative vacuolization and hepatocyte vacuolization. The severity of liver histopathological changes reflected differences in the type of contaminants in different seasons and sampling periods, and was thus proven as a valuable indicator of water quality.
... Zn concentrations were the highest in the gills and liver, and lowest in the muscle (Table 2). Rašković et al. (2014) found similar levels of Cu, As, Mn, and Sr in the liver, of Ba, Mn, Sr, and Zn in the gills, and of Mo in the muscle of the barbel collected in the proximity of our sampling site on the Danube. Another study on the barbel performed by Sunjog et al. (2012) in the vicinity of our sampling site near Belgrade also found similar levels of Cu, Mn, Mo, and Zn in the liver, of Al and Sr in the gills, and of Zn in the muscle tissue. ...
... The higher concentrations of Cu, Zn, and Ni found in fish tissues from the ZM are in accordance with higher concentrations of these elements in the sediment of the ZM compared to the Danube and the JM (Fig. 1). These results support the previous findings by Rašković et al. (2014) and Sunjog et al. (2012) that the barbel has a potential as a bioindicator of metal pollution. The advantages of using the barbel as a bioindicator are its movement characteristics, because it is a resident fish and usually restricted to about 1000 m of activity range. ...
River sediments are a major source of metal contamination in aquatic food webs. Due to the ability of metals to move up the food chain, fishes, occupying higher trophic levels, are considered to be good environmental indicators of metal pollution.
The aim of this study was to analyze the metal content in tissues of the common barbel (Barbus barbus), a rheophilous cyprinid fish widely distributed in the Danube Basin, in order to find out if it can be used as a bioindicator of the metal content in the river sediment. We analyzed bioavailable concentrations of 15 elements (Al, As, B, Ba, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb, Se, Sr, and Zn) in sediments of the Danube (D), the Zapadna Morava (ZM), and the Južna Morava (JM) using the inductively coupled plasma spectroscopy (ICP-OES). The barbel specimens were collected in the proximity of sediment sampling sites for the analysis of metals in four tissues, gills, muscle, intestine, and liver.
The sediment analysis indicated that the ZM is the most polluted with Cu, Ni, and Zn compared to other two rivers. The JM had the lowest concentrations of almost all observed elements, while the Danube sediments were mainly characterized by higher concentrations of Pb. The fish from the ZM had the highest concentration of Cu and Ni in the liver and intestine, and of Zn in the muscle tissue, which was in accordance with the concentrations of these metals in the sediment. Scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM-EDS) was used for further analyses of metal interactions with fish tissues.
The results suggest that the barbel can potentially be used as a bioindicator of sediment quality with respect to metal contamination.
... Thus these biomarkers are often suitable as a rapid method for the detection of both acute and chronic effects of toxins and irritants in various tissues [104]. Histopathological alterations of various fish organs have a pronounced value in aquatic toxicology [105] and they are widely used in monitoring of aquatic pollution [101,102,104,[106][107][108][109]. ...
... Fish gills are in direct contact with the water and subsequently with waterborne pollutants. Their large surface area, direct contact with water, multiple important functions, and delicate structure make them suitable markers for environmental pollution [104, 108,109,155]. Tilapia orally exposed to 60 µg MC-LR/fish/day for 21 days [112] displayed hyperaemia and epithelium lifting. Exposure of European whitefish to various densities of the cyanobacteria Planktothrix rubescens led to epithelial lifting and rupture often leading to exfoliation of epithelial cells, hyperplasia and fusions of lamellae, vacuolization, oedema and apoptosis, and necrosis of epithelial tissue [118]. ...
Cyanobacteria are present in all aquatic ecosystems throughout the world. They are able to produce toxic secondary metabolites, and microcystins are those most frequently found. Research has displayed a negative influence of microcystins and closely related nodularin on fish, and various histopathological alterations have been observed in many organs of the exposed fish. The aim of this article is to summarize the present knowledge of the impact of microcystins and nodularin on the histology of fish. The observed negative effects of cyanotoxins indicate that cyanobacteria and their toxins are a relevant medical (due to irritation, acute poisoning, tumor promotion, and carcinogenesis), ecotoxicological, and economic problem that may affect both fish and fish consumers including humans.
... The main aim of this study was to evaluate the possibility to use combination of qualitative and quantitative histopathological examination of Vardar chub gills as a supplementary indicator of water pollution in mining impacted rivers applying the procedure according to Bernet et al. (1999). That procedure has been widely accepted and applied for histopathology-based evaluation of water pollution (Liebel et al., 2013;Lujić et al., 2015;Rašković et al., 2015). Since chemical and microbiological water quality of three rivers in north-eastern Macedonia which were selected for this study, Bregalnica, Zletovska and Kriva, was determined simultaneously with chub sampling (Ramani et al., 2014), we were able to associate observed histopathological alterations to specific degrees and types of water contamination. ...
... The importance of such approach is supported by the fact that recently several other field surveys of contamination of aquatic ecosystems, which were based on gill histopathology, have been performed in different regions in the world: in Egypt, using Nile catfish (Clarias gariepinus; Authman et al., 2013), in Pakistan, using Mozambique tilapia (Oreochromis mossambicus; Jabeen and Chaudhry, 2013), in Brasil, using fish species Astyanax aff. fasciatus and Nile tilapia (Oreochromis niloticus; Liebel et al., 2013), and in Serbia, using pike (Esox lucius), zander (Sander lucioperca) and Wels catfish (Silurus glanis; Lujić et al., 2015), as well as barbel (Barbus barbus) and sterlet (Acipenser ruthenus; Rašković et al., 2015). Since our study was conducted in two periods, spring and autumn of 2012, which differed concerning fish physiology and physico-chemical characteristic of the river water, seasonal variations of histopathological alterations on Vardar chub gills were also assessed. ...
Quantification of histopathological alterations in the gills of Vardar chub (Squalius vardarensis Karaman) was performed in 2012 in rivers of north-eastern Macedonia, with the aim to examine the effects of water quality in the rivers (Zletovska and Kriva River - impacted by active Pb/Zn mines ; Bregalnica River - contaminated by agricultural waste). The biological alterations in chub were classified as: circulatory disturbances, regressive and progressive changes, but their severity differed. Altogether the mildest changes were observed in the gills of chub from the Bregalnica River, a less polluted river, whereas mining impacted rivers were characterized by more severe alterations. In the gills of chub from the Zletovska River, which is highly contaminated with numerous metals, sulphates and chlorides, the highest lesion indices were found for the regressive changes of both epithelium and supporting tissue, with typical lesions referring to atrophy, thinning and lifting of epithelial cells, necrosis of epithelium and chloride cells, as well as deformations of lamellar cartilaginous base. Gill damages of chub from the Kriva River were overall milder compared to the Zletovska River, in accordance with pollution status. In the gills of chub from that river, progressive changes were more pronounced, specifically severe hyperplasia of mucous cells and epithelium in the interlammellar space, leading to fusion of lamellae, as well as hypertrophy of chloride cells. The comparison between seasons indicated higher intensity of progressive changes in all three rivers in autumn, when water level was very low, and consequently, water contamination was more pronounced due to concentration effect. The pattern and severity of histopathological alterations in the chub gills reflected differences in contamination levels and type of contaminants in different rivers and sampling periods, and thus have been proven as a valuable indicator of water quality.
... The main aim of this study was to evaluate the possibility to use combination of qualitative and quantitative histopathological examination of Vardar chub gills as a supplementary indicator of water pollution in mining impacted rivers applying the procedure according to Bernet et al. (1999). That procedure has been widely accepted and applied for histopathology-based evaluation of water pollution (Liebel et al., 2013;Lujić et al., 2015;Rašković et al., 2015). Since chemical and microbiological water quality of three rivers in north-eastern Macedonia which were selected for this study, Bregalnica, Zletovska and Kriva, was determined simultaneously with chub sampling (Ramani et al., 2014), we were able to associate observed histopathological alterations to specific degrees and types of water contamination. ...
... The importance of such approach is supported by the fact that recently several other field surveys of contamination of aquatic ecosystems, which were based on gill histopathology, have been performed in different regions in the world: in Egypt, using Nile catfish (Clarias gariepinus; Authman et al., 2013), in Pakistan, using Mozambique tilapia (Oreochromis mossambicus; Jabeen and Chaudhry, 2013), in Brasil, using fish species Astyanax aff. fasciatus and Nile tilapia (Oreochromis niloticus; Liebel et al., 2013), and in Serbia, using pike (Esox lucius), zander (Sander lucioperca) and Wels catfish (Silurus glanis; Lujić et al., 2015), as well as barbel (Barbus barbus) and sterlet (Acipenser ruthenus; Rašković et al., 2015). Since our study was conducted in two periods, spring and autumn of 2012, which differed concerning fish physiology and physico-chemical characteristic of the river water, seasonal variations of histopathological alterations on Vardar chub gills were also assessed. ...
... The general bibliometric network (a) and subclusters within the bibliometric network (b) of the key attribute "water temperature of Danube River". 2017; Peycheva et al., 2014;Rašković et al., 2015). ...
This research report provides a comprehensive overview of the historical trends in heavy metal concentrations in the Pontic shad (Alosa immaculata) populations from both the Danube River and the Black Sea, while also exploring the potential influence of global warming on metal accumulation. Through bibliometric modeling analysis, it reveals significant limitations in existing international research, particularly the lack of comprehensive data on the impact of hydroclimatic changes on heavy metal accumulation in Alosa immaculata. Recognizing the critical importance of studies on heavy metal bioaccumulation in Danube shad, this research underscores their significance in defining tolerance thresholds, quantifying the impact of toxic elements along the aquatic food chain, and enhancing the economic sustainability of ichthyofauna monitoring efforts. Furthermore, these studies contribute invaluable insights into the complex dynamics of aquatic ecosystems, offering essential decision-making support for optimizing commercial fishing management practices on the Danube and ensuring robust support systems for industrial fishing endeavors.
... The analysis of HP alterations, together with their scoring and statistical analysis, can show a distinctive pattern of response. This pattern in some studies is species (or genus) specific (Nero et al. 2006;Van Dyk et al. 2009;Rašković et al. 2015), but in some studies, it is not (Dang et al. 2017). Yet, no difference in response pattern between different species sampled from the same site was also reported (Fonseca et al. 2016;Nørregaard et al. 2022). ...
In this study a battery of bioassays, both in vivo (metals and metalloids concentrations, erythrocyte morphometry, comet assay, micronucleus assay, and histopathological analyses) on vimba bream Vimba vimba (L., 1758) and white bream Blicca bjoerkna (L., 1758), and in vitro (treatment of HepG2 cells with native water samples) was applied to assess the harmful potential of untreated wastewater. Faecal indicator bacteria were quantified to assess the microbiological water quality. Vimba bream had significantly higher Fe concentrations in both liver and muscle, while white bream had higher Ca and Cu concentrations in liver. Vimba bream had a significantly higher level of DNA damage in both liver and blood cells, in comparison to white bream. Low levels of micronucleus and nuclear abnormalities were observed in both species. Erythrocytes morphometry did not show significant interspecific differences. Histopathological analyses revealed a similar response of the studied species, with a significantly higher presence of ceroid pigments in the liver of vimba bream. Treatment of HepG2 cells revealed the high genotoxic potential of water downstream of the discharge point. The results of this study clearly demonstrate the importance of effect-based monitoring, in order to enforce more efficient management of natural resources and implementation of wastewater treatment systems.
... In liver almost all HP alterations were associated with Pb and B, while in gills there was larger variation among reaction patterns. A multivariate analysis approach is already being used to explore possible correlation between elemental concentrations and histopathological alterations (Riba et al., 2005;Rašković et al., 2015;Gusso-Choueri et al., 2022), but results can hardly be compared among studies, due to the differences in fish species, environment (marine/freshwater) and the level of contamination. In example, in both Riba et al. (2005) and Gusso-Choueri et al. (2022) the loading matrix and factor scores did not show positive correlation between concentrations of Pb in liver and histopathological alterations, which is in contrast with results from the current study, even though Pb is known to induce necrosis in fish liver upon exposure (Jantawongsri et al., 2021). ...
Five reservoirs (Vlasina, Medjuvršje, Zaovine, Perućac, and Garaši) in Serbia were chosen as study sites, which differ by their position, purpose, stages of eutrophication, management policies, and levels of anthropogenic pressure. The objectives of this research were to: determine the concentrations of 26 elements in muscle, gills, and liver of the European chub by inductively-coupled plasma optical emission spectrometry (ICP-OES); determine the concentrations of 17 organochlorine pesticides in fish muscle by gas chromatography with mass spectrometric detection (GC-MS); compare these findings with condition factor (CF) and histopathological (HP) biomarkers; and assess the potential human health risks due to consumption of chub muscle tissue. The highest elemental accumulation was found in the gills. The European chub was not a good indicator of Pb pollution between reservoirs. Concentrations of Hg, As, and Cu were low and did not exceed the proscribed maximum allowed concentrations (MACs). 4,4′-DDE was detected only in individuals from Vlasina, 4,4′-DDD from Perućac and Zaovine, and heptachlor from Zaovine. Low to moderate levels of HP were observed for both gills and liver in all studied reservoirs. HP index for gills was significantly higher for Zaovine compared to Vlasina. Significantly lower HP index for liver and the total HP index value were observed for fish from Vlasina compared to Perućac. No significant human health risks due to the intake of examined pollutants in each reservoir were recorded; women were at higher risk compared to men. A reason for concern is a few muscle samples from Garaši, Vlasina, Perućac, and Medjuvršje in which Cd exceeded the MAC. A reservoir for water supply (Garaši) is generally considered the safest for fish consumption.
... According to Wang and Rainbow (2000), Golovanova (2008), and Sun et al. (2020) the accumulation of metals in fish tissues is influenced by several factors, including feeding preferences; these studies point out that food is the main route of metal uptake in these organisms. Zoobentivore species are in close contact with sediments, so they are more likely to be exposed to metals in sediments than pelagic fish, which in turn are more exposed to metals in the water column (Rašković et al. 2015). This could explain the differences in Hg concentrations between zoobentivore and pelagic fish in the Tampamachoco Lagoon. ...
... According to Wang and Rainbow (2000), Golovanova (2008), and Sun et al. (2020) the accumulation of metals in fish tissues is influenced by several factors, including feeding preferences; these studies point out that food is the main route of metal uptake in these organisms. Zoobentivore species are in close contact with sediments, so they are more likely to be exposed to metals in sediments than pelagic fish, which in turn are more exposed to metals in the water column (Rašković et al. 2015). This could explain the differences in Hg concentrations between zoobentivore and pelagic fish in the Tampamachoco Lagoon. ...
Trophic transfer and bioaccumulation of trace metals have a profound impact on the structure and function of coastal areas; however, the metal accumulation patterns in detritus-based food webs and the influence of climatic variability have not been thoroughly investigated. The Tampamachoco Lagoon (Gulf of Mexico) is a coastal system impacted by emissions from a thermoelectric plant. We evaluated the spatial–temporal distribution patterns of Al, Cd, Hg, Cr, Cu, and Pb in water, sediments, and in organisms categorized by trophic levels (TLs), trophic guilds, and habitat preferences. The sediments had the highest concentrations of metals with no significant differences between seasons. The indices of geo-accumulation and potential ecological risk classified sediments as “moderately contaminated”, evidencing a threat to human health through consumption of detritivores and filter-feeders. The lowest TLs (filter-feeders and detritivorous) reached the maximum Metal Pollution Index in the rainy season. According to discriminant analyses of metals and species, omnivorous and zoobentivorous organisms were associated with Hg during the rainy and dry seasons; while Al, Cd, and Cu were related to low TLs, and seston was associated with Pb. Food web magnification factor analysis showed that: (a) Pb, Cu, and Cr were biodiluted as trophic levels increased; (b) Cd and Hg showed temporal biomagnification trends; (c) Al, Pb, Cu, and Cd showed significant biodilution from the lowest TL to intermediate TLs; and (d) Hg was transferred from the lowest to intermediate TLs with clear biomagnification effects.
... 2c, 2d). Fibrosis of parenchyma as the intoxication-related modification was comparatively infrequent in fish, differing to mammals, but cholangiofibrosis (Wolf and Wolfe, 2005) and fibrosis of periportal and portal areas (Rašković et al., 2015) were common symptoms. Proliferation of bile ducts was also a predominant histopathological change in the mine draining and tailings areas (Carrola et al., 2009;Jordanova et al., 2016), but this damage was not observed in the present study. ...
The aim of the present study was to assess the concentration of potentially toxic metals (PTMs) like As,
Cd, Cr, Cu, Fe and Pb in the Damsal Nala of Sukinda Chromite Valley, Jajpur of Odisha (India) and its subsequent
histopathological lesions in the fish Puntius sophore. Energy Dispersive X-Ray Fluorescence (EDXRF) and Flame
Atomic Absorption Spectroscopy (FAAS) methods were used to evaluate the concentrations of PTMs in the muscles
of fish, Puntius sophore collected from different zones namely upstream discharge zone (UDZ) and upstream zone
(UZ) of the Damsal Nala and control water bodies (CW). In the UDZ of Nala, the concentration of metals viz., Cd, Pb
and Fe were 2 to 7 times, and Cr was 77 times higher than the maximum permissible limits recommended by WHO
and FAO in the fish muscles. The values of Target Hazard Quotients (THQ) of all these 6 metals were <1 in CW and
UZ, but in UDZ the THQ values of Cr and Fe were >1. Hazard Index (HI) for UDZ was 3.47, indicated the alarming
concentration of metal which can pose serious risk to human health. Histopathological observations in liver and
kidney of Puntius sophore collected from UDZ demonstrated the serious lesions, but mild damage in fish collected
from UZ. These histological alterations and the health risk indices disclosed the effects of effluents of chromite
mining and the impact on the ecological balance which may result into health hazards to the local human population
who are maintaining their livelihood by consuming these fish as protein source.
Keywords: Potentially toxic metals, Health risk assessment, Histopathology, Chromite mine, Puntius sophore,
Hazard index
... Cell death and inflammation constitute two characteristic and related events of chronic liver disease that promotes the onset of fibrosis (Seki & Schwabe, 2015). Rašković et al. (2015) demonstrated the presence of leukocyte infiltration and fibrosis in the liver of benthophagous fish 465 Page 14 of 18 exposed to metals in the Danube. Also, in April, the highest concentration of faecal coliforms (IV class) was observed, indicating high amounts of faecal and organic waste originating from untreated wastewater. ...
This study was conducted on the Danube River locality Višnjica, exposed to the discharge of the largest wastewater collector in Serbia’s capital, Belgrade. Concentrations of metals and metalloids (Al, Fe, Cr, As, Sr, Mn, Cd, Zn, Mo, Cu, Li, Ni, B, Co, Pb, and Ba) and histopathological alterations were investigated in different tissues of common bream during one representative month of each season in 2014. This is the first study in which these two biomarkers were assessed parallelly in common bream. The highest concentrations of examined elements were noticed in gills and the lowest in muscle. Statistically significant differences in element concentrations between different seasons were noticed only in gills for Al, Cu, and Fe. Concentrations of As and Pb in fish muscle were below the maximum acceptable concentrations (MAC). The histopathological index (HI) of the liver showed higher values in comparison to the HI of the gills. Histopathological index of the gills had a significantly higher score in November in comparison to August. The liver HI had the highest score in April, and the lowest in August, while the total histopathological index had the highest score in November, and the lowest in August, both without significant differences between the months. This study endorses gills and liver as reliable organs for studying accumulation and histopathology as biomarkers of environmental changes. A faster reaction of the gills was confirmed since seasonal variations of both biomarkers were observed in this organ. Common bream proved as a good indicator of the state of organisms in polluted environments.
... EGCs are present in gills in low number in non-pathological conditions, while increase in their abundance is reported in fish infected with amoebic gill disease (Adams and Nowak 2004), parasitic copepods, and digeneans from the wild (Dezfuli and Giari 2008;Dezfuli et al. 2013) and are usually accompanied by increase of neutrophils. Increased infiltration of EGCs in the gills of the sea bream (Sparus aurata) exposed to polychlorinated biphenyl was also reported in the dose-dependent response (Lauriano et al. 2012), while gill infiltration of EGCs in two fish species living in the ecosystem with metal pollution also showed distinctive pattern between them Rašković et al. (2015). It is already established in the literature that the same xenobiotic can have different impact to fish immune response, regarding to sex, and endocrine disruptors are recognized as one of the most important modulators of immune system (Magnadottir 2010;Milla et al. 2011;Rehberger et al. 2017). ...
Accumulation of 26 elements (Ag, Al, As, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Se, Si, Sr, and Zn) was analyzed in the gills, liver, and muscle of pikeperch males and females from Garaši reservoir using inductively coupled plasma optical emission spectrometry (ICP-OES). Histopathological (HP) changes in the gills and liver, and human health risk were also analyzed. The gills were most affected by metal pollution in both sexes. The concentrations of Hg in muscle tissue of four males, and Cd in two females and two males exceeded the maximum allowed concentrations. Statistical tests only revealed significant differences regarding the concentrations of Mg, K, and S in the muscle (higher in males) and Al, Ag, and Mn in the liver (higher in females) of individuals between sexes. Low to moderate levels of pathological changes were recorded for the gills and liver in both sexes. Significant differences between sexes were observed for inflammatory index of gills (IGI) and HP index of gills (IG), males had higher values compared to females, and for liver necrosis, where females had higher values compared to males. Gills were less affected by HP changes compared to the liver. There was no significant non-cancerogenic and cancerogenic health risk due to the consumption of pikeperch meat from the Garaši reservoir. However, women are under greater risk by consuming the meat of both male and female individuals, probably due to a longer lifetime and lesser body weight compared to the men.
... Research included species from different trophic levels, such as barbel, burbot (Lota lota), common carp, freshwater bream, pike-perch, Pontic shad (Alosa immaculata), silver carp (Hypophthalmichthys molitrix), sterlet, wels catfish, racer goby (Babka gymnotrachelus), and round goby (Neogobius melanostomus). In most of the analyzed species, metal and trace element concentrations in fish meat were below prescribed MAC (Jarić et al. 2011;Lenhardt et al. 2012a;Sunjog et al. 2012;Subotić et al. 2013a, b;Jovičić et al. 2015;Rašković et al. 2015). However, Trbović et al. (2011) found significantly higher Hg concentrations in the meat of the asp (1.255 mg/kg). ...
The catchment area of the Slovak Danube River Basin (DRB), representing the main river basin of Slovakia is 47,084 km2. This area covers 96.0% of Slovak territory and creates 5.9% of the total DRB (Fig. 1; RBMPDD 2015). The rest of the Slovak territory belongs within the Vistula River Basin (4%). Agricultural land represents c. 50% of the DRB surface, forests and forest-related areas 45% and urbanised areas c. 5%. Average annual precipitation is 738 mm and average annual runoff reaches 228 mm. The territory of Slovakia is located in the temperate climate zone with regular changes of seasons, which is a typical feature of the middle latitudes.
... Research included species from different trophic levels, such as barbel, burbot (Lota lota), common carp, freshwater bream, pike-perch, Pontic shad (Alosa immaculata), silver carp (Hypophthalmichthys molitrix), sterlet, wels catfish, racer goby (Babka gymnotrachelus), and round goby (Neogobius melanostomus). In most of the analyzed species, metal and trace element concentrations in fish meat were below prescribed MAC (Jarić et al. 2011;Lenhardt et al. 2012a;Sunjog et al. 2012;Subotić et al. 2013a, b;Jovičić et al. 2015;Rašković et al. 2015). However, Trbović et al. (2011) found significantly higher Hg concentrations in the meat of the asp (1.255 mg/kg). ...
The Danube River basin represents a hotspot for the European freshwater diversity. The Danube in Serbia is characterized by a significant level of fish diversity, as well as by economically important fish resources. However, the Danube fish fauna is facing a number of adverse anthropogenic impacts, such as unsustainable fishery, habitat loss and fragmentation, water pollution and non-native species invasions. In this chapter, the major adverse impacts on the Danube fish communities in Serbia are presented, and the critical management measures are discussed, such as those related to supportive stocking and other conservation efforts. In order to ensure adequate protection and sustainable management of fish resources in the Danube in Serbia, it will be critical to introduce effective monitoring system, to establish and enforce adequate management measures, and to intensify research efforts on critical issues related to fish management and conservation.
... Sediments are ultimate sinks for various pollutants (Malferrari et al., 2009;Swarnalatha et al., 2013) and play a significant role in the remobilization of contaminants in aquatic systems via natural and anthropogenic processes (Pekey, 2006;Davutluoglu et al., 2011), with a possibility to cause adverse effects on both water quality and human health (Yin et al., 2011). Moreover, the direct transfer of chemicals from sediments to organisms is now considered to be a major route of exposure for many species (Ra skovi c et al., 2015;Morina et al., 2016). ...
Concentrations of As, Cd, Cr, Cu, Hg, Pb, and Zn in sediment samples and muscle tissue of the European perch were analyzed using inductively-coupled plasma optical emission spectrometry (ICP-OES), with the aim to assess the potential ecological (RI) and human health risk, and the degree of contamination (Cd) of three types of reservoirs in Serbia, based on their purpose: electricity generation (Vlasina, Perućac, Zaovine, and Međuvršje), drinking water supply (Garaši), and recreation (Lake Sava). The concentrations of the studied elements were higher in sediments than in fish. However, the levels of Cd in fish caught in Vlasina, Zaovine, and Međuvršje, Hg in Perućac and Garaši, and Pb in Lake Sava exceeded the maximum allowed concentrations. The pollution load index (PLI) indicated that sediments in all six reservoirs were contaminated, but Cd was low; a moderate contamination with Cd was observed in Vlasina, Perućac, and Zaovine, Cr in Zaovine and Međuvršje, and Cu in Međuvršje. A low RI was recorded for all studied reservoirs. Cd was found to be the primary contamination and ecological risk factor. Total target hazard quotient (THQ) and target carcinogenic risk factor (TR) were higher for fishers operating in these reservoirs than for the general population. Higher values of PLI, Cd, RI, and TR were observed in electricity generation reservoirs. Results indicated that this type of reservoirs suffer from higher anthropogenic pressure and/or have a worse pollution management policy compared with other types of reservoirs included in this study, especially the drinking water supply reservoir.
... After prolonged exposure of fish to water contaminants, even in very low concentrations, various morphological and histological alterations occur in different organs, of which the mostly investigated were liver (Adams et al., 2010;Bernet et al., 2000;Giari et al., 2007;Girdoniya, 2016;Jordanova et al., 2016;Poleksic et al., 2010;van Dyk et al., 2009;Zeitoun et al., 2014;Zimmerli et al., 2007), and gills (Barišić et al., 2015;Fonseca et al., 2016Fonseca et al., , 2017Lujić et al., 2015;Rašković et al., 2015). To date, only few studies reported histological alterations in the fish intestinal tissue, most of them in relation to heavy metal exposure and bioaccumulation preferences (Ajima et al., 2015;Bandowe et al., 2014;Ebrahimpour et al., 2011;Liu et al., 2012;Poleksic et al., 2010;Pyle et al., 2005), while only few of them reported the histomorphological endpoints of the intestine in relation to pollution impact (Ferrando et al., 2006;Gaber et al., 2014;Kaoud and El-Dahshan, 2010). ...
In the present study novel histopathological approach, using fish intestine as a sensitive bioindicator organ of pollution impact in the freshwater ecosystem, was proposed. Histopathological alterations were compared between native brown trout (Salmo trutta Linnaeus, 1758) from the reference (Krka River spring) and pollution impacted location (influence of technological/municipal wastewaters and agricultural runoff near the Town of Knin) of the karst Krka River in Croatia. In brown trout from both locations, severe parasitic infestation with acanthocephalan species Dentitruncus trutae was found, enabling evaluation of acanthocephalan infestation histopathology, which indicated parasite tissue reaction in a form of inflammatory, necrotic and hyperplastic response that extended throughout lamina epithelialis mucosae, lamina propria, and lamina muscularis mucosae. New semi-quantitative histological approach was proposed in order to foresee alterations classified in three reaction patterns: control tissue appearance, moderate (progressive) tissue impairment and severe (regressive and inflammatory) tissue damage. The most frequent progressive alteration was hyperplasia of epithelium on the reference site, whereas the most frequent regressive alterations were atrophy and necrosis seen on the polluted site. Furthermore, histopathological approach was combined with micromorphological and macromorphological assessment as an additional indicator of pollution impact. Among 15 observed intestinal measures, two biomarkers of intestinal tissue damage were indicated as significant, height of supranuclear space (hSN) and number of mucous cells over 100 μm fold distance of intestinal mucosa (nM), which measures were significantly lower in fish from polluted area compared to the reference site. Obtained results indicated that combined histological and morphological approach on fish intestinal tissue might be used as a valuable biological tool for assessing pollution impact on aquatic organisms. Therefore, semi quantitative scoring and multiparametric morphological assessment of intestinal tissue lesion magnitude should become a common approach to handle environmental pollution impact.
... Susceptibility to pollutants of fish species living in the same environment is different [18,19]. Age and sex of the fish are also important parameters but not always reported in articles. ...
Fish are regarded as valuable organisms in monitoring aquatic ecosystems. They are established as indicator organisms and widely used in both laboratory studies and ecotoxicology. A range of biomarkers are developed for monitoring effects of xenobiotics on fish. Histopathology is classified as an important biomarker in terms of toxicological significance and highly relevant when chronic or sublethal pollutants are present in the water. In this chapter, a short review of histopathological method is given, with basic guidelines for conducting field studies. The main focus is on different methods for quantifying alterations, namely: semi-quantitative scoring system, histomorphometry and stereology. Advantages and shortcomings of each method are briefly discussed.
... Concentrations of different metals and trace elements among tissues are clearly evident, with the majority being highest in the gills (Al, As, Ba, Cr, Mn, Pb, Sr, Zn), some of them in the liver of chub (Cd, Cu, Fe), while only Hg tends to accumulate the most in the muscles. Other studies in fish mainly confirm these findings (Al Sayegh Petkovšek et al., 2012;Rašković et al., 2015;Sunjog et al., 2012;Uysal et al., 2009), although it is not always the rule, since various concentrations in the water could cause different concentrations in tissues of fish (Has-Schön et al., 2006;Yılmaz et al., 2007). In accordance with Havelková et al. (2008), in mildly contaminated areas, Hg is mainly accumulated in muscle tissue, while in severely contaminated areas Hg is preferentially deposited in the liver. ...
Chub (Squalius cephalus) specimens were collected in Korenita River seven months after spillover from the waste water of antimony mine tailing pond and compared with chub living in Kruščica reservoir (intended for water supply) and Međuvršje reservoir (influenced by intense emission of industrial, urban and rural wastewater). Concentrations of 15 elements (Al, As, B, Ba, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Si, Sr, Zn) were determined in muscle, liver and gills of chub by inductively coupled plasma optical spectrometry (ICP-OES) and histopathological alterations in liver and gills were assessed. Chub specimens from Korenita River had higher concentrations of As, Ba and Pb in all three investigated tissues as well as higher total histopathological index values than chub from reservoirs. Specimens from Međuvršje reservoir were characterized by higher values for concentrations of Cu and Si in muscle tissue and higher values for regressive histopathological alterations in gills. Individuals of chub from Kruščica reservoir had the highest concentrations of Fe in liver, Hg in muscle and Sr and Zn in muscle while gills had the lowest value of total histopathological index. The results from the present study showed higher level of histopathological alterations as a result of mine tailing accident. As a result of mixed contamination on the Međuvršje site, histopathological index values of gills were in line with the index value from Korenita River. Increased values for Fe and Sr in chub tissue from Kruščica reservoir could be explained by geological structure of the site which is characterized by magmatic rock rich in Cu, Fe and Ni as well as dominant carbonate sediment complex of marine origin with increased level of Sr.
... This incapacity of blood to reach the central vein forces liver to pump blood harder which may cause the stress in liver (Olojo et al., 2005). This could be further corroborated by the presence of fibrosis in periportal and portal areas, frequently found in similar field studies Rašković et al., 2015). Within inflammatory alterations the most prevalent was leukocyte infiltration with significantly higher values during summer in comparison to both winter and spring. ...
Biomarkers attract increasing attention in environmental studies, as a tool for detection of exposure and effects of pollution, from both natural and anthropogenic sources. This study aims to assess the impact of multiple stressors during distinctive seasons, covering also extreme hydrological events (extensive flooding in the mid May 2014), on different levels of biological organization in the liver and gills of three closely related freshwater breams. Our previous study on DNA damage in blood cells of these specimens showed increased DNA damage in June 2014, one month after the flooding event. As a continuation of that research, the present study was conducted. As a biomarker of exposure DNA damage was measured by applying the alkaline comet assay, while histopathological alterations were monitored as a biomarker of effect. Additionally, concentrations of metals and metalloids in gills, liver and muscle were assessed. Sampling of fish tissues was performed in 2014, during winter (January and February), spring (March and early June) and summer (late June, July and August). Significant seasonal difference in DNA damage was observed for both tissues. During spring and summer the level of DNA damage in gills was significantly higher when compared to the liver. Histopathological analyses showed higher frequency of alterations in gills during spring, and in liver during summer, but without a significant seasonal difference. Gills had the highest concentration of metals and metalloids during the spring and summer, and liver during winter. Muscle was the least affected tissue during all three seasons. This study highlighted the importance of the multiple biomarker approach and the use of different fish tissues in assessment of surface water pollution.
... Fish gills are in a direct contact with water and present cyanotoxins. Alongside direct contact with water, their large surface area, delicate structure and multiple important functions, make them suitable markers for environmental pollution (Bernet et al., 1999;Rašković et al., 2015;Lujić et al., 2015). Alterations similar to those observed in this study were also observed by some other authors (Rodger et al., 1994;Carbis et al., 1997;Jiang et al., 2011). ...
... To determine the level of pollutant accumulation in fish from the studied area, the heavy metal and trace element concentrations in fish tissues were assessed during 2007-2010 in a number of specimens of the studied species (i.e. 6-30 specimens per species) on the territory of the city of Belgrade (Jarić et al. 2011, Lenhardt et al. 2012, Sunjog et al. 2012, Subotić et al. 2013b, rašković et al. 2014. Specimens were sacrificed with a quick blow to the head, measured for their total weight (g) and total body length (cm), and subsequently dissected. ...
There is a lack of adequate estimates of the fish stocks in the Belgrade city area, Serbia, as well as of the current fishery pressure on fish diversity and of the contamination level of fish meat. These factors obstruct efforts to conduct valorisation of the current state and potential development of this resource. During 2012 and 2013, an assessment of the current state of the fish resources in Belgrade fishery waters was performed, in order to establish a good basis for the development of a monitoring system on the state of fish stocks and their exploitation. Fish were collected at ten localities in the Danube, Sava and Kolubara rivers. The fish stock composition and biomass were determined at each of the localities. The results indicate that the commercial fishery in the Danube and Sava rivers is characterised by seasonal variability regarding the amount and the composition of fish catch, while the ratio of high versus low quality fish remained relatively stable over time. In most of the analyzed fish, heavy metal concentrations remained below the prescribed maximum allowable concentrations (MAC). However, concentrations of mercury, cadmium and zinc exceeded MAC in the tissues of a number of individuals of Wels catfish, common carp, sterlet, pikeperch, European perch, ruffe, and sichel, which indicates that the meat of Danube fish species can be utilised in human diet only in limited quantities, and that it is necessary to establish permanent monitoring of heavy metal concentrations in this area. Based on the results, a system of indicators was defined and a monitoring system for the Belgrade fishery waters was proposed. Pikeperch and freshwater bream were selected as major species for fish meat quality monitoring, while the implementation of fishery monitoring program should comprise both economically important fish species and certain nonindigenous species.
Purpose. To evaluate the variability of the histological parameters of individual organs and tissues of sterlet, to establish the level of effect of heat stress on the physiological status of fish and the degree of their adaptation. To determine the perspective of using histological monitoring data in fish farming practice. Methodology. The primary materials were obtained in aquarium conditions of the Aquatic Bioresources Laboratory of the Kherson State Agrarian and Economic University. The laboratory processing of histological samples was performed according to generally accepted methods and manuals. Histological studies were carried out using the author’s equipment and original methods, specially intended for the diagnostics of fish tissues. The obtained results were processed by methods of variational statistics using a package of appropriate MS Excel applications, with emphasis on the standard error. Findings. Microanatomical studies of sterlet showed that under conditions of heat stress, the most significant changes occur in adipose tissue, somatic and cardiac muscle tissue, thyroid gland and renal tissue, which can conditionally be considered as bioindicative zones. Under the potential influence of the thermal factor, the response of sterlet is expressed in a decrease in the lipid content in the accompanying muscles of adipose tissue. The effect is visualized in the fragmentation and subsequent shredding of lipid vacuoles, which leads to variability in adipocyte shape from stellate to spindle-shaped. The obtained results indicate a decrease in the excretion of thyroid hormones into the bloodstream by the thyroid gland and is expressed in a gradual increase in the diameter of the thyroid follicles (by 16.0 µm and 26.5 µm) and a corresponding decrease in the height of the follicular cells (by 1.1 µm and 2.0 µm), which is statistically significant. Intensive development of “additional” follicles inside existing ones indicates the prevention of thyroid intoxication of the body, which indicates the development of an adaptive reaction of the body. Comparative studies of the ventricular myocardium of fish allowed establishing certain morphological differences in the form of moderate interstitial edema of the tissue and intracellular edema of cardiomyocytes. In the final phase of the experiment, karyopyknosis was locally observed in the ventricular cardiomyocytes of 50% of stressed fish. Somatic muscle tissue is generally resistant to stress, but the rate of its development at elevated temperatures slows down. Characteristic signs of the histological picture of muscle stress are approximately the same ratio of stromal and parenchymal components, the central orientation of the nuclei within a single muscle fiber and insufficient filling of the fibers with the fibrillar component. Antidiuretic hormone is forcedly released in fish under conditions of heat stress, which leads to a decrease in the volume of the primary filtrate. Evidence is a narrow gap in the urinary space between the visceral and parietal layers of the renal corpuscle. Originality. New data are presented and existing data on the histological structure of individual organs and tissues of sterlet under stress loads are significantly expanded. For the first time, a detailed histological analysis of the structure of muscle, adipose tissue, as well as the kidney and thyroid gland of sterlet under heat stress conditions was carried out. The comparative analysis, current and updated information on compensatory changes in tissues demonstrate their adaptive potential, which was developed during the evolution of the species. Practical Value. The information obtained is of value in morphophysiological studies as well as in fish farming practice in connection with the modern problem of a decrease in the life status of fish under stress. The use of the obtained data allows a qualitative assessment of the physiological state and can be used in the process of developing corrective measures in order to consolidate hereditary resistance, which is ultimately aimed at preventing diseases of valuable aquaculture objects. Keywords: sterlet, heat stress, adaptation, muscle tissue, thyroid gland, myocardium, adipose tissue, renal tissue.
Juveniles of three cyprinids with various diets and habitat preferences were collected from the Szamos River (Hungary) during a period of pollution in November 2013: the herbivorous, benthic nase (Chondrostoma nasus), the benthivorous, benthic barbel (Barbus barbus), and the omnivorous, pelagic chub (Squalius cephalus). Our study aimed to assess the accumulation of these elements across species with varying diets and habitat preferences, as well as their potential role in biomonitoring efforts. The Ca, K, Mg, Na, Cd, Cr, Cu, Fe, Mn, Pb, Sr, and Zn concentration was analyzed in muscle, gills, and liver using MP-AES. The muscle and gill concentrations of Cr, Cu, Fe, and Zn increased with trophic level. At the same time, several differences were found among the trace element patterns related to habitat preferences. The trace elements, including Cd, Pb, and Zn, which exceeded threshold concentrations in the water, exhibited higher accumulations mainly in the muscle and gills of the pelagic chub. Furthermore, the elevated concentrations of trace elements in sediments (Cr, Cu, Mn) demonstrated higher accumulation in the benthic nase and barbel. Our findings show habitat preference as a key factor in juvenile bioindicator capability, advocating for the simultaneous use of pelagic and benthic juveniles to assess water and sediment pollution status.
The chapter presents the history of fisheries in Serbia from 1860 until today. The chapter discusses the development of society (political, social, economic) and its relationship to fisheries and fishery resources. Additionally, an analysis of the development of fisheries legislation and its practical application in commercial and recreational fisheries was carried out. The main impacts on fish stocks in the past and present are analyzed, such as the fragmentation of large rivers (Danube, Drina) by hydroelectric dams, the creation of reservoirs for the water supply on the smaller rivers, the construction of small hydropower plants on mountain rivers, land reclamation and agricultural development, deforestation, the impact of allochthonous species, pollution, overfishing, and illegal fishing. Official statistical data on the fish catches by commercial fishermen over the last 70 years in the fisheries waters of Serbia are analyzed and compared. Estimates and difficulties in estimating fishing pressure by recreational anglers are presented, as well as suggestions for overcoming these problems. The current state of fish stocks can be characterized as the following: at the limit of sustainability for parts of the Danube, Sava, and waters in some protected areas, moderately sustainable for most fishing waters, and very sustainable for some reservoirs in the Great Morava and Drina basins, a small number of salmonid waters, and protected pond ecosystems.
Aquaculture as a production of aquatic plants and animals in objects intended and custom-made for this purpose is furthermore one of the ways how to alleviate, rehabilitate, even entirely solve the problem of endangered freshwater fish species. Since the natural fish resources are limited globally, there is a raising demand for fish as food. This is the reason why today, from the total quantity of fish consumed globally, 50% originates from aquaculture. Besides this primary role of aquaculture, it became an important way to renew endangered fish and other aquatic organisms’ populations in their natural aquatic habitats. This new task of aquaculture is of extreme importance for the preservation of ichthyofauna as well as other aquatic organisms’ diversity, primarily endangered and protected species. In addition to positive effects on hydrobionts’ biodiversity, preservation of autochthonous, primarily protected fish species in their natural environment opens possibilities for improvement of recreational and game fishery, and consequently socio-economic reinforcement of local communities placed near the natural aquatic ecosystems.
The increase in the world’s population increases the levels of pollutants in the aquatic environment. Among different xenobiotics, the concentration levels of potentially toxic elements are very important due to their negative effects on living organisms, including humans. Western Balkan mainly includes underdeveloped countries with the unresolved issue of wastewater and consequently a large number of pollutants in fishing water. All commercial fishing waters (except the Tisza River) are transboundary and there are no borders for pollutants in water, so we can observe Western Balkan as a single territory regarding aquatic pollution. The aim of this chapter is to present a comprehensive traditional literature overview of studies related to the contamination of fishing waters (used for commercial fishing) of the Western Balkans, with special reference to pollution with potentially toxic elements (PTEs) and their impact on the ecological sustainability of fish resources. This review has shown that research regarding this issue has been very limited over the last two decades. The most studied fish species were from the Danube and Sava rivers, and they were also the most polluted with PTEs. Elevated concentrations of Fe, Zn, Hg, Cd, As, and Ni were found in fish species in the Danube River, while elevated concentrations of Hg were recorded in fish species sampled from the Sava River, downstream from Zagreb. Transboundary lakes used for commercial fishing have been very little investigated and there are only a few studies on PTEs in fish. However, elevated concentrations of Cd and Pb were reported in fish from Lake Prespa.
Citation: Sudakov, N.P.; Chang, H.-M.; Renn, T.-Y.; Klimenkov, I.V. Degenerative and Regenerative Actin Cytoskeleton Rearrangements, Cell Death, and Paradoxical Proliferation in the Gills of Pearl Gourami (Trichogaster leerii) Exposed to Suspended Soot Microparticles. Int. J. Mol. Sci. 2023, 24, 15146. https:// Abstract: The effect is studied of water-suspended soot microparticles on the actin cytoskeleton, apoptosis, and proliferation in the gill epithelium of pearl gourami. To this end, the fish are kept in aquariums with 0.005 g/L of soot for 5 and 14 days. Laser confocal microscopy is used to find that at the analyzed times of exposure to the pollutant zones appear in the gill epithelium, where the actin framework of adhesion belts dissociates and F-actin either forms clumps or concentrates perinuclearly. It is shown that the exposure to soot microparticles enhances apoptosis. On day 5, suppression of the proliferation of cells occurs, but the proliferation increases to the control values on day 14. Such a paradoxical increase in proliferation may be a compensatory process, maintaining the necessary level of gill function under the exposure to toxic soot. This process may occur until the gills' recovery reserve is exhausted. In general, soot microparticles cause profound changes in the actin cytoskeleton in gill cells, greatly enhance cell death, and influence cell proliferation as described. Together, these processes may cause gill dysfunction and affect the viability of fish.
The Danube is the second-largest river in Europe and has been subject to pollution in the past. Additionally, in the last few years, the rapid pace of industrialization and urbanization has led to the inevitable pollution of this aquatic ecosystem by certain metals (essential and non-essential elements). This issue is considered the central problem of pollution in the Danube and is gaining increasing attention. Fish is a good source of proteins, polyunsaturated fatty acids (especially omega-3 fatty acids), essential vitamins, and minerals. Fish are often exposed to metals present in their aquatic environment through direct contact with contaminated water or by consuming organisms that have accumulated metals in their tissues; therefore, the elevated concentrations of metals in water and sediments are reflected in the fish flesh. In this context, the safety of fish and fishery products for human consumption is a public health concern. In the last two decades, more and more reports have shown that Danube River fish are contaminated with metals, causing great concern among consumers. The negative perception continues, although recent scientific studies show that metal levels in the edible parts of the fish are below acceptable limits. The objective of this study was to put together a multitude of scientific research studies that investigate the levels of some metals in various tissues of some fish species with high economic value in the Romanian market, as well as the levels of metals in the water and sediments. The collected data were then utilized to assess the potential health risks posed to humans.
Background:
This study aims to explore the effect of liver stem cells (LSCs)-derived exosomes and the miR-142a-5p carried by them on the process of fibrosis by regulating macrophages polarization.
Methods:
In this study, CCL4 was used to establish liver fibrosis model. The morphology and purity of exosomes (EVs) were verified by transmission electron microscopy, western blotting (WB) and nanoparticle tracing analysis (NTA). Real-time quantitative PCR (qRT-PCR), WB and enzyme-linked immunoadsorption (ELISA) were used to detect liver fibrosis markers, macrophage polarization markers and liver injury markers. Histopathological assays were used to verify the liver injury morphology in different groups. The cell co-culture model and liver fibrosis model were constructed to verify the expression of miR-142a-5p and ctsb.
Results:
Immunofluorescence of LSCs markers CK-18, epithelial cell adhesion molecule (EpCam), and AFP showed that these markers were up-regulated in LSCs. In addition, we evaluated the ability of LSCs to excrete EVs by labeling LSCs-EVs with PKH67. We found that CCL4 and EVs were simultaneously treated at 50 and 100 μg doses, and both doses of EVs could reduce the degree of liver fibrosis in mice. We tested markers of M1 or M2 macrophage polarization and found that EVs reduced M1 marker expression and promoted M2 marker expression. Further, ELISA was used to detect the secreted factors related to M1 and M2 in tissue lysates, which also verified the above views. Further analysis showed that the expression of miR-142a-5p increased significantly with the increase of EVs treatment concentration and time. Further, in vitro and in vivo LSCs-EVs regulate macrophage polarization through miR-142a-5p/ctsb pathway and affect the process of liver fibrosis.
Conclusion:
Our data suggest that EVs-derived miR-142-5p from LSCs improves the progression of liver fibrosis by regulating macrophage polarization through ctsb.
Triphenyltin (TPT) has attracted considerable attention owing to its vitality, bioaccumulation, and lurking damage. TPT widely exists in complex salinity areas such as estuaries and coastal regions. However, there are few studies on the toxicological behavior of TPT under different salinity. In the study, juvenile Nile tilapia (Oreochromis niloticus) were utilized as model animals to investigate the effects of environmental relevant TPT exposure on the osmoregulation and energy metabolism in gill under different salinity. The results showed that salinity and TPT single or combined exposure affected the morphology of the gill tissue. After TPT exposure, Na⁺-K⁺-ATPase (NKA) activity significantly decreased at 0 ppt, while NKA and Ca²⁺-Mg²⁺-ATPase (CMA) activities significantly increased at 15 ppt. In addition, significantly higher succinate dehydrogenase (SDH) and lactate dehydrogenase (LDH) activities were found in the control fish compared to the TPT-exposed ones at 15 ppt. Quantitative real-time PCR results showed that TPT exposure affected the expression of osmoregulation and energy metabolism-related genes under different salinity. Overall, TPT exposure interfered with osmoregulation and energy metabolism under different salinity. The study will provide reference data for assessing the toxicity of organotin compounds in complex-salinity areas.
The toxic influence of soot microparticles on terrestrial organisms has been well studied, although there is scarce data on how microparticles could affect hydrobionts. We performed a first-ever study of the short-term (5 days) impact of furnace soot (0.005 g/L) on the structural and functional features of gill cells in the Baikal Sculpin species Paracottus knerii, Dybowski, 1874. The soot samples used in the experiment were composed of small (10–100 nm) particles and larger (up to 20 μm) aggregates. The dominant fractions of the polycyclic aromatic hydrocarbons of these microparticles were phenanthrene, fluoranthene, pyrene, benzo[a]anthracene, chrysene, benzofluoranthenes, benzopyrenes, indeno[1,2,3-c,d]pyrenes, and benzo[ghi]perylene. Trace element analysis of the soot detected the presence of C, S, Si, Al, Ca, K, Mg, P, and Fe. The gill condition was assessed with electron scanning, transmission, and laser confocal microscopy. Soot induces degenerative changes in the macrostructure and surface of secondary lamellae and increases mucus production in fish gills. A decrease in mitochondrial activity, an increase in reactive oxygen species production, and an increase in the frequency of programmed cell death in gill epithelium were observed under the influence of soot. In chloride cells, an induction of macroautophagy was detected. In general, the changes in fish gills after the short-term influence of soot microparticles indicate the stress of respiratory and osmotic regulation systems in fish. The data obtained are important for forming a coherent picture of the impact of soot on hydrobionts and for developing bioindication methods for evaluating the risks of their influence on aquatic ecosystems.
Vimba bream (Vimba vimba) individuals were collected from the Danube River near Belgrade, from May 2016 to May 2017. Samples of muscle and liver tissue were analyzed for concentrations of 25 elements (macro-, micro-, and toxic elements) using inductively coupled plasma optical emission spectrometry (ICP-OES). For both tissues, the highest concentrations of most elements were observed in late spring/early summer (months of May and June). Majority of statistically significant correlations between elements were positive in both tissues. Contributions of Ca, K, and Mg to human diet were in a similar range. The lowest contribution of all macroelements was observed for Na, while the contribution of Se was well above the recommended dietary allowance for this element. Levels of detected elements were well below MAC values prescribed by national and international regulations. The highest value of Hg liver/muscle index (>1) was observed in August, which could indicate a higher contamination of the sampling location in that month. Se:Hg molar ratio never drops below 1, which could indicate that Hg toxicity is prevented. THQ values showed little variation thought the year and were well below the threshold of 1, with the exception of THQ for Al in May (0.92). This element also strongly affects the hazard index.
The article describes a new locality of the formed wintering riverbed depression discovered in the erosion zone of the isthmus of conjugate meanders of the Irtysh river for the rational use and effective protection of aquatic biological resources in places of their concentration in the Irtysh river basin (Western Siberia, the Russian Federation. The morphology of the riverbed depression was mapped (relief and bathymetric maps). The maximum depths in the channel depression exceeded 27 m. The channel depression and 4 control river sections were studied. The analysis of hydroacoustic surveys showed that in the wintering riverbed depression there is, according to the statistical data, higher fish density compared to the control areas: in the water area of the riverbed depression the average fish density made 4 524 species/ha, in the control sections 245-2091 sp./ha. The cluster analysis based on the fish density and the size-taxonomic composition of the ichthyofauna has revealed that the riverbed depression is being separated into a cluster, but at the same time goes to the control section No. 4, which is located downstream, where further erosion of the river channel is registered. In this regard, the minimum protection zone of the wintering channel depression should include the water area of the channel depression and the water area of control section No. 4. In the water areas of the riverbed depression and control sections in the spring period, cyprinids dominate - up to 65% of the total number of fish, percids are represented to a lesser extent - 36.76%, coregonids and pikes - up to 18.18, sturgeons - up to 9.31%. The given locality of the wintering riverbed depression must be included in the list of protected river sections of the Fishing Rules for the West Siberian fishery basin for developing the effective strategy for the protection, restoration and rational use of aquatic biological resources, including rare and endangered fish species of the Irtysh River and the whole Ob-Irtysh basin.
This study was conducted on individuals of European perch from six reservoirs in Serbia with different properties, used for different purposes, and situated at different altitudes. Samples of muscle, gills, and liver, as well as water samples, were used for analysis of elemental accumulation. Histopathological (HP) analysis of gills and liver, and Fulton's condition factor (CF) were used as biomarkers. Analysis of Ag, Al, As, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Se, Si, Sr, and Zn was conducted by inductively-coupled plasma optical emission spectrometry (ICP-OES), and accordingly, metal pollution index and bioaccumulation factor (BAF) were calculated. Elemental accumulation varied considerably both among tissues and reservoirs. Reservoirs located on large low-altitude rivers were the most heavily polluted with metals (Međuvršje, on the Zapadna Morava River, and Lake Sava, on the Sava River). Of three tissues analyzed, the gills were most affected by pollution. The levels of Hg in muscle decreased with an increase in reservoir altitude. Specimens sampled from the highest altitude reservoir were the least affected by HP alterations; however, HP differences between the reservoirs were not statistically significant, and the severity of HP changes was generally low. No significant correlations between the elemental accumulation or HP indices with CF were observed.
The article presents the review of scientific works on ecology and biology of sterlet aspects of its distribution, spawning, migration, feeding and accumulation of heavy metals in organs and tissues. It has been stated that in natural populations there are two morphs - with a sharp (long) and blunt (short) rostrum. It has been assumed that they are characterized by the separation of spawning period into time intervals. In artificial aquaculture sterlet individuals show a decrease in morphometric traits, which may result from the identical farming conditions or the reduction of genetic diversity. The background color of the tanks used for cultivation can affect the linear-weight characteristics of fish: in light colored tanks there are fish of smaller sizes, in dark colored ones - fish of larger sizes. It has been found that the color of the species body similar to the bottom substrate acts as s a highly effective protection against predators in turbid waters. The study of sterlet population of in the Ob’-Irtysh and Yenisei basins showed that the former population has a higher genetic diversity index. Migration length of sterlet is insignificant: up to 250 km. It spawns in the spring-summer period, in winter period it concentrates in the wintering holes. The leading role in sterlet feeding belongs to the representatives of benthos and zooperiphyton, which are characteristic of lithophilic, lythoreophilic and psammoreophilic biocenoses. Maximum concentrations of heavy metals have been registered in the liver and gills, minimal in the muscles. The largest accumulation of elements is noted for Fe, Al and Zn, the minimum for Cd and Co.
Atrazine is a herbicide that is banned in Europe but remains widely used on different types of crops in several countries in the American continent. Atrazine is known to be an endocrine disruptor and its effects on gonads have been extensively reported, but the toxic action on other organs is poorly documented. In this paper, we investigated the toxicity of atrazine on the gills and spleens of Nile tilapia (Oreochromis niloticus). The median lethal concentration (LC50), capable of killing one-half of the test animals was calculated, and sublethal concentrations of atrazine were used in a semistatic and subchronic assay. The following four experimental groups were formed: control not exposed to atrazine, a group exposed to 1 ppm atrazine for 15 days, a group exposed to 2 ppm for 7 days, and a group exposed to 2 ppm for 15 days. The concentrations were verified during the study by high performance liquid chromatography. The gills and spleens were stained with hematoxylin and eosin and histopathological findings were made. The Perls technique was used on the spleens to identify hemosiderin, lipofuscin, and melanin pigments in the cells from melanomacrophage centres (MMCs). The spleens were submitted to proliferating cell nuclear antigen (PCNA) and inducible nitric oxide synthase (iNOS) immunohistochemistry, and morphometry was used to assess splenocyte proliferation and melanomacrophage iNOS expression. Finally, a colorimetric assay for caspase-3 was performed on the spleens to identify apoptosis. Vascular and structural alterations, such as venous sinus congestion, aneurysm, hemorrhage, pillar cell hypertrophy, disarrangement of secondary lamellae, and epithelial lifting were observed in the gills. The frequency of individuals with aneurysms was higher in the groups treated with 2 ppm than in other groups. Atrazine had an immunomodulatory effect on the spleen, observed by the alteration in the percentage of red and white pulp, alteration of the MMC area, changes in the melanomacrophage pigment content, slight iNOS suppression, decrease in splenocyte proliferation under 1 ppm atrazine, and increased caspase 3 activity under 2 ppm atrazine after 7 and 15 d. Such effects could compromise oxygenation and the immune response and, ultimately, the survival and fitness of the fish.
Female individuals of Hyphessobrycon eques were exposed to Diflubenzuron (Dimilin®) in order to determine whether exposure to sublethal levels of this insecticide causes changes in gill morphology. Fish were exposed to 0.01, 0.1 and 1.0 mg L−1 for 96 h and 17 days and then submitted to pathological and histometric evaluation. Pathological lesions, such as hyperplasia, lamellar fusion, vascular congestion, secondary lamellar disarray, vasodilatation, hemorrhage and increased lamellar epithelium, were significantly more common in the gills of fish exposed to Dimilin® than the control. Histometric analysis documented significant changes in blood vessel diameter, primary lamellae width and secondary lamellae length, and the appearance of hemorrhage foci in all concentrations tested. Even at low Dimilin® concentrations, the histopathological alteration index was mild to moderate, thereby indicating that the function of this tissue was compromised. These findings indicate that indiscriminate use of Dimilin® can adversely affect the structural integrity of the gills of H. eques, which can cause numerous problems for fish farming systems.
The semi-intensive system of common carp monoculture in earthen ponds is currently the most practiced fish rearing system in several countries in Eastern Europe. This system is based on the addition of supplemented feed to ponds to achieve faster growth. In this study, the general state of the fish health was monitored when three different types of feeds were used: grain cereals (CF), commercial pelleted feed and extruded feed. The markers used were: (i) the histopathological index (HP) of the main organs: gills, liver and kidney; and (ii) the histomorphometric parameters of the hepatocytes and enterocytes to assess the state of the digestive system in fish fed different types of supplemented feed. At the end of the experiment, the fish were in good health, since irreversible lesions were not noticed to a greater extent in any of the fish organs. There were also no other severe lesions present. However, the results showed differences in the HP indices of the liver and gills, as well as the total HP index, indicating a better health status of the fish in the CF group. The histomorphometric results showed larger cytoplasmic areas of hepatocytes in fish fed CF, which is attributed to glycogen accumulation and higher numbers of goblet cells in the distal intestines of fish fed compound feeds. This can be attributed to slight inflammation.
Altogether 701 adult barbel, Barbus barbus were captured by electrofishing and individually tagged to study their local displacement and movements in a stretch of the River Jihlava (Czech Republic). A total of 149 fish were recaptured and 105 of them (70.47 %) were considered as "resident" because they were always recaptured in the same, relatively restricted (250 - 780 m) stream section, which always contained a pool and was demarcated naturally by riffles on both edges. The remaining 44 recaptured specimens (29.53 %) belonged to the "mobile" part of population, their movements encompassing two (or exceptionally more) adjacent stream sections and at maximum a distance of 1680 m downstream or 2020 m upstream. The proportion of mobile barbel, relatively low in smaller and middle size classes, increased in the largest size classes (451-550 mm of SL). A rather limited extent of movements also suggests a relatively small area of home range in the studied stretch, which nevertheless provides satisfactory resources and favourable conditions required by barbel over their entire life cycle. The extent of movements and corresponding proportion of mobile fish appear to be increasing with diminishing habitat patchiness. In the stretch of River Jihlava studied, with a rich patchy heterogenous habitat and well developed riffle-pool-raceway structure, each section (pool) can be considered as a more or less isolated spatial unit containing its own, and in a certain degree, isolated component of a metapopulation.
Infection of the barbel Barbus barbus (L. 1758) with endohelminths was observed in fish collected from eight localities in the Serbian part of the Danube River between September 2004 - 2009. Temporal variations in the number of parasites per fish sample were noted. A total of 194 fish specimens of different age, mostly males, were examined. The most prevalent parasitic species was the acanthocephalan Pomphorhynchus laevis, the dominant species of the intestinal component communities at all sampling sites which were recorded in 100% of the fish examined.
In order to evaluate the relationship between water quality in ponds and indices of histopathological changes occurring in the vital organs of the common carp (Cyprinus carpio L., 1758), two six-month field experiments were carried out using two different water supplies: from the nearby stream and a tube well. The fish were fed supplemental feed: raw cereals, pelleted and extruded compound feed. Histopathological analysis, alteration frequencies, and semi-quantitative scoring of the changes were used to assess the health status of the fish. Ponds supplied by stream water were characterized by higher water hardness, dissolved oxygen and pH values, while those supplied by the tube well had higher electroconductivity, total ammonium and orthophosphates content. Fish survival rate and habitat suitability index were lower in ponds supplied by stream water, while the weight gain did not differ between the two water supplies. The use of stream water resulted in a higher level of histopathological changes in gills and liver. Among the water quality parameters, pH level had the strongest influence on fish. Differences in water supply produced greater influence on the level of histopathological changes than the type of feed applied. Gills were the most sensitive organ, while the kidney was the least responsive.
Histopathological changes were identified in selected target organs from two freshwater fish species, Clarias gariepinus and Oreochromis mossambicus, inhabiting the hyper-eutrophic Roodeplaat Dam near Pretoria. A histology-based fish health assessment protocol was used, including a semiquantitative histopathological assessment of the gills, liver, ovaries, testes, kidney and heart. Water quality analyses showed selected variables to be above the recommended levels, including pH, ammonia, nitrogen, chloride and phosphorus. A number of histopathological alterations were identified in the target organs of both species, with the highest number being in the liver. Species differences were identified in terms of the severity of the alterations within all the organs, with most alterations being regressive in nature. This study provided valuable baseline data that could be useful for future biomonitoring studies.
Here I quantitatively review the literature on how fish gill morphology is affected by chemical and physical irritants in the surrounding water (e.g. various toxicants, extremes of temperature or pH). I catalogued histopathological gill lesions that were reported, and used statistics to explore how such lesions relate to the irritant-exposure conditions under which they occurred (specifically, to dose and class of irritant, to temperature, and to salinity of the surrounding water). Frequently recorded histopathologic lesions include changes in gill epithelium (lifting, necrosis, hyperplasia, hypertrophy, rupture), bulbing or fusing of gill lamellae, hypersecretion and proliferation of mucocytes, and changes in chloride cells and gill vasculature. I conclude that these lesions are largely nonspecific in nature, as each was detected under many different exposure conditions. The lesions are not entirely independent of exposure conditions, however, as my statistical analysis discerns these trends: (1) Most gill lesion types have been reported more frequently after lethal than after sublethal exposure to irritants. (2) Some lesions were more frequently detected in studies employing heavy metals than in studies using organic toxicants or other irritants; such lesions include necrosis and hypertrophy of gill epithelial cells, plus mucous hypersecretion. (3) Lifting of the branchial epithelium, the most commonly reported lesion, was reported more often in freshwater than in marine fish, suggesting that osmolarity of the ambient water influences this lesion. Little relation was found between recorded lesion frequencies and temperature. Following my statistical analysis, the etiology of irritant-induced gill lesions is considered. The nonspecificity of branchial alterations suggests that they primarily represent stereotyped physiological reactions of gills to stress, and many of them are logically considered defense responses. Some branchial alterations have been considered inflammatory, but I conclude that the literature cannot support that hypothesis. Ultrastructural studies have detected irritant-induced disruptions of branchial epithelial cells, including cytoplasmic vacuolization, autophagosomes and inclusions, loss of microvilli, and abnormal mitochondria and nuclei.
The health status of four commercially and ecologically important fish species from the Okavango Delta was assessed, using a histology-based health assessment protocol, to establish baseline data for future toxicity studies. Following the calculation of a necropsy-based health assessment index (HAI), the histological responses of the liver, gills and gonads were assessed and compared between Clarias gariepinus, C. ngamensis, Oreochromis andersonii and Serranochromis angusticeps. Population HAI results showed that O. andersonii was most affected in terms of necropsy-related alterations, followed by S. angusticeps, whilst identical low values were calculated for C. ngamensis and C. gariepinus. Quantitative histological results corresponded with the HAI results. The liver and gills of O. andersonii were most affected in terms of the percentage prevalence of the histological alterations identified. These were mostly associated with inflammation, and progressive and regressive changes. The histology of the liver and gills was also more affected in terms of the type and severity of the histological alterations identified, compared to that in the gonads of all four species. The majority of alterations were most likely caused by the prevalence of parasitic infections.
Nile tilapia, Oreochromis niloticus, of both sexes were reared in freshwater and exposed to 0.5, 1.0 and 2.5mg L-1 of waterborne copper for a period of 21 days. Liver and gill samples were collected after 21 days of exposure to copper and lesions were analyzed by light microscopy. The main histopathological changes observed in gills exposed to the highest concentration were edema, lifting of lamellar epithelia and an intense vasodilatation of the lamellar vascular axis. Although less frequent, lamellar fusion caused by the filamentar epithelium proliferation and some lamellar aneurisms were also found. The liver of control group exhibited a quite normal architecture, while the fish exposed to copper showed vacuolation and necrosis. These hepatic alterations were more evident in fish exposed to 1.0 and 2.5mg L-1 copper concentrations. The number of hepatocytes nucleus per mm2 of hepatic tissue decreased with the increase of copper concentration. In contrast, the hepatic somatic index was high in fish exposed at 2.5mg L-1 of copper. In short, this work advance new knowledge as influence of copper in the gill and liver histology of O. niloticus and demonstrated that their effects could be observed at different concentrations.
To investigate effects of short-term mercury (Hg) exposure in tilapia (Oreochromis niloticus) including histopathological changes, Hg bioaccumulation, and protective role of metallothionein (MT) in different exposure routes, adult tilapias were intraperitoneally injected, orally intubated, or semistatically exposed to 0.5, 1, 2, 5 µg/g mercuric chloride. Histopathology, autometallography (AMG), inductive coupled plasma-atomic emission spectrometry (ICP-AES), and MT immunohistochemistry were determined at 0, 3, 6, 9, 12, and 15 days postexposure. Microscopic lesions were observed in the kidney, hepatopancreas, spleen, and intestine. AMG positive grains were found in renal tubule epithelium, melanomacrophage centers (MMCs), and intestinal epithelium of treated tilapias. Hg concentrations measured by ICP-AES in abdominal visceral organs were significantly higher than in other organs. All exposure routes caused lesions of increasing severity and Hg accumulations in a dose-dependent manner. Semistatic groups produced the highest intensity of lesions, AMG positive staining, as well as total Hg concentrations. Positive MT expression in renal tubule epithelium, pancreatic acini, and splenic MMCs was observed only in semistatic groups. The semistatic exposure route demonstrated the most significant microscopic lesions, Hg bioaccumulation, and MT expression.
Effects of heavy metals on physiological and biochemical parameters of fishes and water invertebrates have been reviewed.
The mechanisms of uptake and detoxication, and the influence of various biotic and abiotic factors on heavy metals (predominantly
Cu, Zn, Cd, and Hg) toxicity in fishes and water invertebrates are considered.
The aim of this study was to analyze 16 trace elements (Al, As, B, Ba, Cd, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, Pb, Sr, and Zn) in different barbel (Barbus barbus) tissues and to detect the presence of genotoxic effects in erythrocytes with the alkaline comet assay. Barbel specimens were collected in the Danube river near Belgrade, Serbia, where the discharge of untreated communal and industrial wastewaters is likely to produce negative effects on fish residing in this area. The highest concentrations of Sr, Mn, Fe, Ba, B, and Al were found in gills, Mo and Cu in liver, and As and Zn in gonads. Concentrations of Zn and Fe were above maximum acceptable concentrations (MACs) in a number of gonad, gill, and liver samples. Three-year-old barbel specimens had higher tail moment and Zn concentrations in gills (1.71 and 51.20 μg/g dw, resp.) than 5-year-old specimens (0.85 and 42.51 μg/g dw, resp.). Results indicate that the younger barbel specimens might be more suitable for the monitoring of environmental pollution.
In the marine environment, mercury is accompanied by selenium in all investigated species of mammals, birds, and fish--possibly due to a normal homeostatic regulation. It therefore seems likely that selenium will exert its protective action against mercury toxicity in the marine environment, decreasing its detrimental effects on reproduction, behavior, growth, etc. of the organisms and thus protect the population and ecosystem. On the other hand, the increased retention of mercury caused by selenium may lead to a higher level of biomagnification in the food chain and a higher burden in the individual. This might counteract the positive effect of decreased intoxication.
Water quality guidelines for industrial effluents are in place in many countries but they have generally evolved within a limited ecotoxicological framework. Effluents from iron-ore mines have traditionally been viewed by regulatory bodies as posing little or no risk to the aquatic environment. However, it was recently reported that lake trout taken from a large iron-ore contaminated Lake in Labrador (Wabush Lake) had elevated levels of DNA oxidative damage and were markedly depleted in levels of vitamin A (Payne et al., 1998) in comparison with fish from a Lake (Shabogamo Lake) receiving lesser levels of effluents. Through further observations, it has now been established that the lake trout in Wabush Lake are commonly affected with a marked skin bleaching syndrome in comparison with fish in Shabogamo Lake and a nearby Lake (Ashuanipi) which does not receive effluents. To the authors' knowledge such a syndrome which is characterized by marked reduction in skin pigmentation and overall increase in skin whitening has not been reported before in any fish population in association with contamination. Preliminary information for liver histopathological and blood cell differences have also been obtained in fish in Wabush Lake in comparison with Ashuanipi Lake. It has also been observed through studies on phosphatidyl liposomes that iron-ore leachate contains redox-active material (iron but possibly other transition metals) that has considerable potential for causing oxidative damage to cellular constituents. Using the weight of evidence approach it is indicated that iron-ore effluents may pose more of a risk to the aquatic environment than traditionally considered by regulatory agencies.
Biochemical assays are not routinely used to assess liver damage in fish, therefore, a histopathological evaluation is usually required to determine the existence or extent of nonneoplastic liver toxicity. Many mammalian pathologists may be uncomfortable when requested to identify and interpret subtle liver changes in these unfamiliar animals. It may be reassuring to note that there are more similarities than differences between fish and mammals in terms of their macro- and microanatomy, physiological and biochemical characteristics, and pathologic responses to hepatotoxic substances. This brief overview addresses several topics pertaining to hepatotoxicity in fish, including: anatomic considerations, that is, how the anatomy of the fish liver may be predictive of its metabolic capacity, and also its microscopic appearance, following exposure to toxins; physiologic considerations, including comparisons between mammalian and fish livers regarding the uptake, elimination, toxification, or detoxification of xenobiotic compounds; morphologic responses to toxicity, in which some of the general types of findings that are most commonly observed in cases or studies of fish hepatotoxicity are highlighted; and last, responses of the fish liver to specific hepatotoxins.
While a large surface area combined with short diffusion distances make fish gills well suited for gas exchange, these properties leads to costly water and ion fluxes and exposure to toxic substances and pathogens. Thus, gill morphology is likely to be a compromise between opposing demands. It has become clear that some fishes have the ability to modify gill structure in response to environmental parameters such as oxygen levels and temperature. Maybe the most dramatic example of gill plasticity is the adaptive and reversible changes in gill surface area displayed by crucian carp (Carassius carassius) and goldfish (Carassius auratus). Here, a cell mass is filling up the space between the lamellae during normoxic and cold conditions (i.e. when oxygen demands are low). Hypoxia or high temperature induce apoptosis and suppress mitosis in the interlamellar cell mass causing it to retract and the lamellae to protrude. The functional importance of oxygen and temperature induced changes in gill morphology and the underlying mechanisms are discussed.
The present paper provides the results of the study on feeding of juvenile (underyearlings and age 2+) sterlet (Acipenser ruthenus) caught in the Danube River in 2002–2003. The full spectrum of food items found in the fish stomachs was identified. The seasonal patterns of food composition are revealed. It is shown that juvenile sterlet in the Danube feeds mainly on larvae of chironomids and trichopterans, amphipods, and leeches. The organisms typical for lithophilic and lithorheophilic biocenoses play considerable role in the feeding of sterlet. Mean daily gains of body length and weight in the sterlet underyearlings are calculated.
Water pollution induces pathological changes in fish. As an indicator of exposure to contaminants, histology represents a useful tool to assess the degree of pollution, particularly for sub-lethal and chronic effects. However, a standardized method for the description and assessment of histological changes, mainly for use in freshwater fish, is still lacking. In this paper, the present authors propose a standardized tool for the assessment of histological findings which can be applied to different organs. The methodology is based on two factors: (1) the extension of a pathological change is rated with a ‘score value’; and (2) the pathological importance of this alteration is defined as an ‘importance factor’. The sum of the multiplied score values and importance factors of all diagnosed changes results in different indices. With these indices, statistical analysis can be carried out. Assessment methods for the gills, liver, kidney and skin are described.
Macrophage centres have been considered as a potentially useful indicator of fish health. In this histological work we tested this hypothesis with macrophage centres (MCs) in the spleen, the liver and the hematopoietic part of the kidney of two common freshwater fish species in Finland, perch (Perca fluviatilis) and roach (Rutilus rutilus). Samples were collected over 5 seasons from a system of 4 lakes providing a gradation in water quality. The mean number of MCs/mm2 and the area covered (μm2/mm2) by them differed between individual fish, species, organs, and lakes, with interactions amongst these factors. Hemosiderosis was recorded from the spleen and liver of both fish species; amounts differed between species of fish, organs, and lakes. None of the observed patterns agreed with rankings of water quality, and we conclude that macrophage centres have limited usefulness as indicators of pollution.
The literature on mast cells/eosinophilic granule cells (MCs/EGCs) of teleosts is reviewed. By employing special techniques of fixation, embedding and staining, several investigators have been able to demonstrate cells with metachromatically stained cytoplasmic granules characteristic of the mast cell in tissue samples from species belonging to a diverse group of teleostean families, including cyprinids, erythrinids, esocids, salmonids, pleuronectids and molids. Besides showing metachromasia with dyes like toluidine blue and thionin, these cells can also be stained with Alcian blue, retaining the blue colour after sequential staining with safranin. Most of the studies referred to were performed on intestinal tissues, gills or skin, and in the majority of species fixation of tissue samples in water-based fixatives had to be avoided to preserve the basophilic components of the granules. With other preparation and staining procedures the cytoplasmic granules are acidophilic, i.e. they appear red after staining with haematoxylin and eosin, displaying the characteristics of EGCs. Susceptibility to watery fixatives and/or blockade of metachromatic staining with aldehydes is a feature of mammalian mucosal mast cells. Massive recruitment of mucosal mast cells and increased acidophilia of the granules of such cells when they enter epithelia from subepithelial tissue layers and become ‘ globule leucocytes ’ (intraepithelial mucosal mast cells) in response to infection with intestinal parasites is well-known in intestinal tissues of mammals. In teleostean fish, similar responses seem to occur in parasitized intestine, gills and skin. By applying the concept of mast cell heterogeneity, as described for mammals, the results from studies hitherto published indicate that MCs/EGCs of teleosts are mast cells of the mucosal mast cell type, which is not surprising since most studies on teleostean MCs/EGCs are focusing on cells in mucosal tissues
Physiological measurements suggest that mercury (Hg) affects ion regulation in aquatic organisms. This implies that Hg should cause morphological changes in gills, the major ionoregulatory organ of fish. Previous studies have shown severe Hg-induced gill damage at acutely lethal Hg concentrations, but in soft fresh waters, where ionoregulatory disturbances should be most pronounced, there have been no quantitative studies to date of the effects of dissolved Hg at sublethal concentrations. We exposed mosquitofish (Gambusia holbrooki) to nominal concentrations of 75, 150 and 300 nM Hg (II) in natural stream water of low ionic strength (Ca = 4.8 μM) in a static-renewal experiment. Mercury concentrations dropped rapidly after Hg additions, and most dissolved Hg was probably complexed with humic substances. Gills were sampled after 7 and 14 days exposure. Examination with scanning electron microscopy (SEM), indicated that Hg caused progressive loss of secondary lamellae and loss of cell surface microridges. Effects became more severe at higher Hg concentrations. Using light microscopy and morphometric techniques, the percent of gill filament occupied by chloride cells (volume density) was significantly greater in all Hg treatments than in controls, and thickness of the primary lamellar epithelium increased with Hg exposure. Thickening of the primary lamellar epithelium filled some interlamellar spaces, obliterating secondary lamellae. However, width of the exposed portions of secondary lamellae was not affected by Hg, suggesting that blood-to-water diffusion distances did not increase in response to Hg exposure. Autometallographic staining for Hg showed that the metal was distributed throughout the gill epithelium, and not concentrated inside chloride cells.
This paper reports on a comparative perspective of liver histopathological data of the sharptooth catfish Clarias gariepinus. The data was collected from a spectrum of relatively un-impacted and isolated, to polluted, eutrophic freshwater ecosystems. Results were compared between regional areas, by combining data from freshwater systems which has a similar pollution status and/or is located within the same geographical region. Measurements included necropsy observations, semi-quantitative liver histopathology (Liver Index), and selected biometrical indices. The aim was to establish whether the results of these measurements would differ between, and/or reflect the pollution status of, the different freshwater aquatic ecosystems. The histopathological analysis showed a higher prevalence of toxicopathic non-neoplastic, and pre-neoplastic alterations in C. gariepinus from the polluted sites. We also found a significant difference between the Liver Index, hepatosomatic index, and condition factor values of fish inhabiting impoundments known to be polluted, compared to the same species from the selected reference sites. Fish from polluted sites also had more macroscopic liver abnormalities. The results suggest that the liver histopathology of this bio-indicator fish species could be a useful biomarker of freshwater aquatic pollution.
A series of specific toxicological effects including bioaccumulation of the pollutant, histological changes and influences on cholinesterase (ChE) activities were examined in the adult Japanese medaka after the exposure to graded sublethal concentrations (40, 20, 10, 5, 2.5ngHg/mL) of methylmercury chloride (MMC). Methylmercury (MeHg) contents in the exposed medaka tissues ranged from 0.03 to 64.4μgHg/g (wet weight, w.w.). High concentrations of MeHg were accumulated in the liver and brain, while the concentrations in muscle and fat were relatively low. A dose-dependent and exposure time-dependent increase of MeHg contents in tissues was observed. Histopathological changes, such as oedema, vacuolization, pyknotic nucleus, telangiectasis, and degenerative sperm, can clearly be observed in the slices from the liver, gill, and male gonad of the exposed medaka. Inhibition of ChE activity was common in the exposed fish's brain, liver, gill, and muscle. The serious intoxication of MMC to medaka was definitely demonstrated herein.
The sterlet (Acipenser ruthenus L.) is a bottom-feeding fish species with a direct exposure to contaminants from water and sediments. Although heavy metal pollution is believed to be one of the main threats to the sterlet population in the Danube River basin, there is a lack of knowledge of the exact impact of heavy metals on their survival. In the present study, effects of heavy metal pollution on sterlet in the Danube basin were assessed as well as the utility of different sterlet organs and tissues as indicators of heavy metal contamination. The sterlet were sampled at three different sites in the Danube basin, in Hungary and Serbia, isolated from each other by dams. Heavy metal analysis included measurement of Cd, As, Pb, Cr, Hg, Cu, Ni, Fe, Mn, and Zn concentrations in sterlet gills, muscle, liver, and intestine, and histopathological analyses comprised assessment and scoring of the extent and intensity of alterations in skin, gills, and liver tissue. Analysis revealed a significant presence of sublethal histopathological changes that were most pronounced in the liver and skin and increased accumulation of heavy metals, with the highest concentrations in the liver. Canonical discriminant analysis showed significant differentiation among the three studied localities, suggesting that the heavy metal concentrations in sterlet populations were site specific. The present study concludes that the accumulation of heavy metals is a response to the presence of these pollutants in the environment, and, together with other pollutants, it affects the vital organs of natural sterlet populations.
The ability of selenium (Se) to moderate mercury (Hg) toxicity is well established in the literature. Mercury exposures that might otherwise produce toxic effects are counteracted by Se, particularly when Se:Hg molar ratios approach or exceed 1. We analyzed whole body Se and Hg concentrations in 468 fish representing 40 species from 137 sites across 12 western U.S. states. The fish samples were evaluated relative to a published wildlife protective Hg threshold (0.1 sg Hg x g(-1) wet wt.), the currenttissue based methylmercury (MeHg) water quality criterion (WQC) for the protection of humans (0.3 microg Hg x g(-1) wet wt) and to presumed protections against Hg toxicity when Se:Hg molar ratios are >1. A large proportion (56%) of our total fish sample exceeded the wildlife Hg threshold, whereas a smaller, but significant proportion (12%), exceeded the MeHg WQC. However, 97.5% of the total fish sample contained more Se than Hg (molar ratio >1) leaving only 2.5% with Se: Hg ratios <1. All but one of the fish with Se:Hg <1, were of the genus Ptychochelius (pikeminnow). Scientific literature on Se counteracting Hg toxicity and our finding that 97.5% of the freshwater fish in our survey have sufficient Se to potentially protect them and their consumers against Hg toxicity suggests that Se in fish tissue (Se:Hg molar ratio) must be considered when assessing the potential toxic effects of Hg.
This paper reviews studies on mercury and selenium interaction. It includes the effects of selenium on mercury toxicity on the organism, organ/tissue, and subcellular levels. The paper also touches on possible mechanisms for the "protective action" of selenium against mercury toxicity and deals briefly with the synergism between the two elements.
Copper sulfate is one of the most widely used algicides for the control of phytoplankton in lakes, reservoirs, and ponds. It is also used for aquatic weed control. To study the toxic effects of copper on carp (Cyprinus carpio L.), toxicity tests were carried out. Fish recovery in copper-free water was followed. After a 14-day period of exposure to five concentrations of copper sulfate (0.25-4.0 mg/L CuSO4, values ranging from approximately 5 to 70% of the 96-h LC-50) and a recovery period of the same duration, activities of the functional enzymes alkaline phosphatase (AP), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) in the blood serum and gills were determined. Because the gills are the known target organ for copper, changes in gill structure were investigated as well. In all exposure groups for all the enzymes studied, an increase in activity was noted after 14 days. The increase in AP activity was the most pronounced in both gills and serum of carp exposed to the highest concentration tested (4 mg/L). After a "recovery" period, compared with the end of treatment, a decrease in enzyme activities was recorded, indicating eventual recovery from the Cu-induced stress (the only exception being the ALT activity in gills in the highest CuSO4 concentration). The results of biochemical analysis were confirmed by histopathology. Lesions such as epithelial hyperplasia, curling of secondary lamellae, and changes in chloride cells were observed on the gills, and their severity increased with increased toxicant concentration. Most of the changes were reversible, as exhibited by gill histopathology after the recovery period.
The Joint Danube Survey (JDS)--a comprehensive monitoring survey to assess the environmental pollution status of the river Danube--was carried out in 2001. Samples were taken at 74 positions along the river from Neu-Ulm (River-km 2589) down to the Danube Delta at the Black Sea (River-km 0) and in 24 main tributaries and anabranches. Besides other biological and chemical parameters, concentrations of Al, As, Cd, Cr, Cu, Fe, Pb, Mn, Hg, Ni, and Zn were determined in sediments and suspended solids. Lowest heavy metal concentrations were measured around River-km 1800. After an increase down to River-km 1000 (the Irongate Reservoir), a constant level or a slight decrease could be found down to and in the Danube Delta. Very high element concentrations were determined at only a few stations of the river Danube and in some tributaries. An evaluation of the pollution status of the river was carried out by enrichment factors (EFs) calculated using adapted background concentrations of heavy metals. Except single sampling sites and some tributaries, the pollution of the river Danube by As, Cr, Cu, Pb, Hg, Ni, and Zn can be regarded as rather low. However, elevated concentrations of Cd were found in both investigated matrices, particularly in the lower stretch of the river Danube beginning at the Irongate.
This study assesses the applicability of a sentinel fish species as a biomonitor of metal pollution. Gudgeon (Gobio gobio) were collected from 14 sites in metal polluted lowland rivers in Flanders, including a clear Cd and Zn pollution gradient. Fish tissues were analysed for Cd, Cr, Cu, Ni, Pb and Zn. Metal levels in organs were related to levels in water and sediment. At some sites Cd and Zn levels were up to 50 times higher compared to reference values and literature. Significant relationships between Cd and Zn in fish tissue and environmental levels were found, especially in the pollution gradient where up to 70% of the observed variation could be described. Condition factor differed significantly among the sampling sites but could not be directly related to the environmental metal levels. Nevertheless, in the pollution gradient, threshold tissue concentrations could be defined above which the condition factor was always low.
Melano-macrophage centres, also known as macrophage aggregates, are distinctive groupings of pigment-containing cells within the tissues of heterothermic vertebrates. In fish they are normally located in the stroma of the haemopoietic tissue of the spleen and the kidney, although in amphibians and reptiles, and some fish, they are also found in the liver. They may also develop in association with chronic inflammatory lesions elsewhere in the body and during ovarian atresia. In higher teleosts, they often exist as complex discrete centres, containing lymphocytes and macrophages, and may be primitive analogues of the germinal centres of lymph nodes. Melano-macrophage centres usually contain a variety of pigments, including melanins, and these increase in range and volume in older fish or in the presence of cachectic disease. Melano-macrophage centres act as focal depositories for resistant intracellular bacteria, from which chronic infections may develop. Iron capture and storage in haemolytic diseases appears to be a primary function, but antigen trapping and presentation to lymphocytes, sequestration of products of cellular degradation and potentially toxic tissue materials, such as melanins, free radicals and catabolic breakdown products are among other functions that have been ascribed. Recent work suggests that they are a site of primary melanogenesis rather than mere storage. Melano-macrophage centres increase in size or frequency in conditions of environmental stress and have been suggested as reliable biomarkers for water quality in terms of both deoxygenation and iatragenic chemical pollution.
Methylmercury is a potent toxic present in Amazonian fish species due to gold mining activities. In the present work, we investigated the morphological effects of methylmercury in liver and kidney of Hoplias malabaricus feeding contaminated prey fish over 70 days. Two groups of nine mature fish (tested and control) were acclimatized for four weeks to laboratory conditions and then the tested group fed prey fish previously contaminated at an additional level of 0.075 microg MeHg g(-1) at 5-day intervals and over 14 successive intervals whereas control group fed uncontaminated fish. H. malabaricus specimens were then dissected for chemical and morphological analyses. The low and realistic level of MeHg in the prey fish induced a low increase of total mercury in liver (1.8-fold) and muscle (2.2-fold). The biomagnification factor (Hg in predator/Hg in prey) reached 142 in liver and 21 in muscle and was indicative of a relatively fast contamination of internal organs by dietary exposure. The liver of exposed individuals presented leukocyte infiltration, increased number of melano-macrophage centers, necrotic areas and lesions in Disse's space. Evident disorder and chaos in cytoskeleton organization suggest a strong toxic effect in hepatocytes, such as organelles positioning and movement, vesicles traffic and secretion. Head kidney showed large necrosis areas, increased number of melano-macrophages centers, phagocytic areas, intercellular space among parenquimal cells and atypical cells. Injuries and damages to tissues suggest too slow defense mechanisms to immobilize or eliminate ingested methylmercury, demonstrating that the sensitivity of fish cells to methylmercury exposure is higher than it has been previously described in the literature.
Migracija riba u reci Dunav i njegovim pritokama, njen uticai na stanje i dinamiku populacija ekonomski važnih riba kao i ribolov
- Ristić
Ristić MD. 1970. Migracija riba u reci Dunav i njegovim pritokama, njen uticai na stanje i dinamiku populacija ekonomski
va znih riba kao i ribolov. Ribarstvo Jugoslavije 25:1-15 [in
Serbian].
Are metal mining effluent regulations adequate: Identification of a novel bleached fish syndrome in association with iron-ore mining effluents in Labrador, Newfoundland
- Payne