Metal Concentrations In Gills Research Articles

Heavy metal concentrations in sediments and Cyprinus carpio from Maqalika Reservoir –Maseru, Lesotho: An analysis of potential health risks to Fish consumers

The determination of heavy metal contaminants in fish is very important in monitoring health risks to humans who consume them. This study assessed the concentration of heavy metals (As, Pb and Zn) in sediments and gills of Common Carp fish (Cyprinus carpio) from Maqalika Reservoir in Maseru, Lesotho and their potential health risks to such fish consumers. Sediment and Cyprinus carpio samples were collected from upstream, midstream and downstream sites of Maqalika Reservoir and examined for As, Pb and Zn using atomic absorption spectrometer. Potential health risks were based on comparing the derived metal concentrations in gills of Cyprinus carpio with the World Health Organization (WHO) permissible limits for human consumption. The mean concentration levels of Zn, As and Pb in sediment were in the order: 78.5; 2.34; and 0.29 mg/kg respectively. In the gills of Cyprinus carpio the mean concentration levels were in the order 7.85; 1.29; and 0.33 mg/kg for Zn, As and Pb respectively. The magnitude of concentration of Zn, As and Pb by location in the reservoir varied spatially in the order of downstream > midstream > upstream in both sediment and gills of Cyprinus carpio. Significant differences (p < 0.05) in metal concentrations between upstream and downstream sites of the reservoir were observed. The metals concentration in gills of Cyprinus carpio were lower than those in sediments, but positively and significantly correlated (P < 0.05). As and Pb concentration levels in the gills of Cyprinus carpio were higher than the WHO permissible limits recommended for fish consumption of 1 mg/kg and 0.2 mg/kg respectively, suggesting that residents could experience significant health risks from the intake of individual metals through fish consumption. Measures should be taken to reduce heavy metal concentrations in sediment and Cyprinus carpio exposure in the general population in order to minimize the risk of human health adverse effects.

Peruvian scallop Argopecten purpuratus: From a key aquaculture species to a promising biondicator species

The present study analyzed the Peruvian scallop Argopecten purpuratus and its food sources for metal and fatty acid concentrations in order to determine spatial and temporal differences. Metals such as copper (Cu), manganese (Mn), and zinc (Zn) in gills and iron (Fe) and Zn in sediments were the most significant explaining factors for spatial differentiations (degree of contamination), while for fatty acids, it was C14:0, C15:0, C16:0 and C18:0 in A. purpuratus' muscle and in its food sources, which explained more temporal differences (El Niño-Southern Oscillation (ENSO) effect). Gills, digestive gland and intestine were the tissues where metal accumulation was the highest in A. purpuratus. Cd in digestive gland was always high, up to ∼250-fold higher than in other tissues, as previously reported in other bioindicator species for metal pollution. Fatty acids were good biomarkers when annual comparisons were performed, while metals when locations were compared. ENSO 2017 played an important role to disentangle A. purpuratus’ biological conditions and food sources. A. purpuratus from Paracas locations mostly showed higher metal concentrations in gills and digestive glands, and lower fatty acid concentrations in muscle than those from Sechura and Illescas Reserved Zone.

Metal accumulation and expression of genes encoding for metallothionein and copper transporters in a chronically exposed wild population of the fish Hyphessobrycon luetkenii

In the present study, metal (As, Cd, Cu, Fe, Mn, Pb and Zn) accumulation and expression of genes involved in metal metabolism (metallothioneins, ATP7A and CTR1) were evaluated in gills and muscle of the fish Hyphessobrycon luetkenii living in the João Dias creek, a site historically (~1870–1996) contaminated with a metal mixture associated with copper mining (Minas do Camaquã, southern Brazil). Fish were collected in a metal impacted site of the João Dias creek and kept in a cage at this site (PP fish) or translocated to a non-metal impacted reach of this creek (PC fish). Gill metal concentrations and metallothionein gene expression were lower in PC fish than in PP fish at any experimental time (24, 48 and 72 h). In muscle, no significant changes were observed. These findings indicate that metal accumulated in gills of wild fish chronically exposed to the metal mixture are more easily excreted than those accumulated in the muscle. In this case, expression of gene encoding for metallothionein is shown to play a key role in the regulation of metal accumulation in gills of H. luetkenii living in an area historically contaminated with a metal mixture associated with copper mining.

Safety assessment on microbial and heavy metal concentration in Clarias gariepinus (African catfish) cultured in treated wastewater pond in Kumasi, Ghana

ABSTRACTThis study assesses the microbial and heavy metal distribution in African catfish (Clarias gariepinus) cultured in waste stabilization pond, and their subsequent suitability for human consumption. Treated wastewater-fed pond (WFP) was used in the culture of the fish with a non-wastewater fed pond (NWFP), fed with ground and rain water as control. Pond water, sediments and fish tissue (gill, liver, gut and skin) samples from both sources were analyzed for pathogens and heavy metal levels. Escherichia coli populations in the sediments and water from the WFP exceeded the maximum permissible limit by 2–3 log units as expected. Significantly higher levels of pathogen contamination were detected in the gut and skin of fish from the WFP than the NWFP. Heavy metal concentrations in all samples fell within the Food and Agricultural Organization (FAO)/World Health Organization (WHO) and National Oceanic and Atmospheric Administration (NOAA) permissible limits except for iron and cadmium. There were significantly higher heavy metal concentrations in gill and liver than the muscle. Even though iron recorded the highest concentrations in fish tissue, the concentrations (0.1–2.0 mg kg−1) were below the expected daily nutritional requirement (1–2 mg) for humans and pose no toxicological risk. However, catfish from WFP would require precautionary measures such as cooking/grilling prior to consumption to avoid pathogen infection.

THE USE OF EFFECTIVE MICROORGANISMS (EM) AS A PROBIOTIC ON CULTURED NILE TILAPIA; OREOCHROMIS NILOTICUS

Nowadays, and due to different anthropogenic activities, the environmental conditions deteriorate and consequently productivity of cultured and wild fish decreases. The present study highlights the role of effective microorganisms (EM) as a probiotic in enhancing biological features and growth performance of the cultured Nile tilapia (Oreochromis niloticus) exposed to copper metal under experimental conditions. Other metals that may interfere with toxic effects of copper on fish were measured. The conducted toxicity test showed that the copper 96hr LC50 is 6.30 mg/l, thus fish of the experimental groups were exposed to 0.1 of that dose (0.630 mg/l) as a sublethal chronic dose for 12 weeks. After this long-term exposure period, metal concentrations in gills, liver, kidney, muscles and skin of O. niloticus showed significant increase in the copper exposed group associated with histopathological changes and clear damage in gills, liver and kidney tissues comparing to the EM exposed group. Moreover, the results revealed significant improvement in growth indices, histological and biochemical aspects of EM exposed fish. The present study recommends the use of effective microorganisms in fish farms to enhance fish productivity and reduce the toxic effects of pollutants.

English

Gills and muscles of Tilapia fish from Naik lake of Nagpur city were estimated for heavy metals (Zinc, Lead, Nickel, Copper and Cadmium) using inductively coupled plasma optical emission spectrometry (ICP-OES). Results showed higher concentrations of heavy metals in gills than in muscles of tilapia fish. Trends of heavy metal concentrations in gills and muscles of tilapia fish were found Zn > Pb> Ni> Cu >Cd. Highest lead and cadmium levels in muscles of the fish were 83±0.07 µg/g dw and 13±0.21 µg/g dw respectively. These levels were above the maximum permissible limits of Food and Agriculture Organization (FAO)/World Health Organisation (WHO). The results confirmed that tilapia fish from Naik lake are not safe for human consumption. Further, the health risks related to Zn, Pb, Ni, Cu and Cd were assessed based on target hazard quotients (THQ). The health risks from lead and cadmium were found to be the highest among all heavy metals in the study. THQ values of lead and cadmium were 4.0108, and 2.450, 0.818 and 2.57, 1.53 and 0.513 for person who eat tilapia fish from Naik lake five times, three times and once a week respectively. Maximum allowable daily consumption rate (CRlim) for lead and cadmium in tilapia fish from Naik Lake was 0.0015 kg/day and 0.0024 kg/day respectively. Highest allowable weekly (CRwm) and monthly (CRmm) consumption rates for lead and cadmium in tilapia fish from Naik Lake were 0.0105 kg/week , 0.0168 kg/week and 0.198 kg/month, 0.318 kg/month respectively. Above these values of highest allowable daily, weekly and monthly consumption rates for lead and cadmium are unsafe for inhabitant who eats tilapia fish from Naik lake. Health risk assessment of lead and cadmium in tilapia fish from Naik lake suggests that consumption of fish from Naik lake might be unsafe for humans. Regular assessment of heavy metals in fish in Naik lake must be conducted to assure food safety. Key words: Health risk estimation, heavy metals, tilapia fish, allowable daily consumption, target hazard quotients.

Heavy Metal Concentrations in Gills and Muscle of Local and Imported Tilapia in Port Harcourt, Nigeria

The concentrations of Arsenic (As) and Cadmium (Cd) were measured in the gills and muscle of Sarotherodonmelanotheron (a locally available species) and Tilapia zilli (imported from China) in Port Harcourt in 2012 to establish their suitability for consumption as food. The samples S. melanotheron and T. zilli were derived from Creek Road market and a cold-room in Mile One Market respectively.The heavy metal analysis was performed using Flame Atomic Absorption Spectrophotometer AAS model GBC Avanta Pm. The levels of metal varied in the organs and in the fish species. Mean concentrations of As in S. melanotheron were 0.74±0.06 mg/kg and 0.68±0.07 mg/kg in gill and muscle respectively. Cd was 0.098±0.001 mg/kg in gill and 0.026±0.015 mg/kg in muscles. In T. zilli As concentration was 0.64±0.04 mg/kg in gills and 0.53±0.04 mg/kg in muscle. Cd concentration was 0.18±0.009 mg/kg in the gills and 0.17±0.063 in the muscles. The concentration of As in S. melanotheron was not significantly different from that in T.zilli , while Cd was significantly higher (p T. zilli . Concentrations of As and Cd in T.zilli and As in S. melanotheron were above WHO (1981) permissible limit. The implication of these levels was discussed.

Heavy metal concentrations in gill and liver tissues of Rutilus kutum and Chelon aurata in the coast of Babolsar, southern Caspian Sea

Heavy metal accumulation in the aquatic ecosystems is a main concern which threats human health. In this study two commercial fish species, Rutilus kutum and Chelon aurata were selected for assessing heavy metal (Cd, Pb, Zn) concentrations in gill and liver tissues at Babolsar’s coast, the southern Caspian Sea, Iran. Babolsar is one of the important fishery stations in the southern Caspian Sea. The results showed that liver tissue of C. aurata significantly accumulated higher concentration of Cd, Pb and Zn compared to that of R. kutum , but these results were not significant for gill tissue. Liver tissue accumulated higher concentration of Cd and Pb compared to gill tissue in C. aurata , but these results were not significant for R. kutum . It is concluded that the liver tissue of C. aurata has higher potential to accumulate heavy metal pollution compared to liver tissue of R. kutum

Histological alterations under metal exposure in gills of European perch (Perca fluviatilis L.) from Topolnitsa Reservoir (Bulgaria)

Topolnitsa Reservoir is located in a region of Bulgaria rich in copper mines where intensive mining has been ongoing for several decades. General data on the ecological status of the reservoir and the effects of metal on fish is relatively scarce. The first aim of the study was to measure the concentrations of six metals (As, Cd, Cu, Ni, Pb and Zn) in water samples and in the gills of European perch (Perca fluviatilis L.). The second objective was to examine gill structure and determine the severity of histological alteration as a result of metal exposure. Surface water and fish gill samples were collected in spring, summer and autumn in 2012 and metal and histological analyses were performed. Metal concentrations in the water samples varied, but only Cu concentrations were determined in all three seasons and they were higher than the maximum permissible levels. The gill metal concentrations were significantly higher (P&lt;0.05) than in the water. Examination of gill structure revealed the presence of proliferative and degenerative changes, as well as changes in the blood vessels. Histological lesions were similar in their severity in all three seasons. This study provides the first information about metal effects on the morphology of European perch gills from Topolnitsa Reservoir. It can be concluded that the metal contamination of the Topolnitsa Reservoir and fish is chronic and that it can negatively affect the structure and function of fish gills. As metals display a tendency to accumulate in fish gills, their effects are expected to become more severe with time, as they affect gill functions. &lt;br&gt;&lt;br&gt;&lt;font color="red"&gt;&lt;b&gt; This article has been corrected. Link to the correction &lt;u&gt;&lt;a href="http://dx.doi.org/10.2298/ABS1801215E"&gt;10.2298/ABS1801215E&lt;/a&gt;&lt;u&gt;&lt;/b&gt;&lt;/font&gt;

Correlation of transcriptomic responses and metal bioaccumulation in Mytilus edulis L. reveals early indicators of stress

Marine biomonitoring programs in the U.S. and Europe have historically relied on monitoring tissue concentrations of bivalves to monitor contaminant levels and ecosystem health. By integrating ‘omic methods with these tissue residue approaches we can uncover mechanistic insight to link tissue concentrations to potential toxic effects. In an effort to identify novel biomarkers and better understand the molecular toxicology of metal bioaccumulation in bivalves, we exposed the blue mussel, Mytilus edulis L., to sub-lethal concentrations (0.54μM) of cadmium, lead, and a Cd+Pb mixture. Metal concentrations were measured in gill tissues at 1, 2, and 4 weeks, and increased linearly over the 4 week duration. In addition, there was evidence that Pb interfered with Cd uptake in the mixture treatment. Using a 3025 sequence microarray for M. edulis, we performed transcriptomic analysis, identifying 57 differentially expressed sequences. Hierarchical clustering of these sequences successfully distinguished the different treatment groups demonstrating that the expression profiles were reproducible among the treatments. Enrichment analysis of gene ontology terms identified several biological processes that were perturbed by the treatments, including nucleoside phosphate biosynthetic processes, mRNA metabolic processes, and response to stress. To identify transcripts whose expression level correlated with metal bioaccumulation, we performed Pearson correlation analysis. Several transcripts correlated with gill metal concentrations including mt10, mt20, and contig 48, an unknown transcript containing a wsc domain. In addition, three transcripts directly involved in the unfolded protein response (UPR) were induced in the metal treatments at 2 weeks and were further up-regulated at 4 weeks. Overall, correlation of tissue concentrations and gene expression responses indicates that as mussels accumulate higher concentrations of metals, initial stress responses are mobilized to protect tissues. However, given the role of UPR in apoptosis, it serves as an early indicator of stress, which once overwhelmed will result in adverse physiological effects.

Correlation of MT Levels in Livers and Gills with Heavy Metals in Wild Tilapia (Oreochromis mossambicus) from the Klang River, Malaysia

Metallothionein (MT) concentrations in gill and liver tissues of Oreochromis mossambicus were determined to assess biological response of fish to levels of some metals. Metal concentrations in gill and liver tissues of O. mossambicus ranged from 0.6 to 2.6 for Cd, 16 to 52 for Zn, 0.5 to 17 for Cu and 2 to 67 for T-Hg (all in μg/g wet weight, except for T-Hg in ng/g wet weight). Accumulation of Cd, Zn, Cu and Hg (μg/g wet weight) in the liver and gills of O. mossambicus were in the order of liver > gills. The concentrations of Cd, Zn, Cu and Hg in fish tissues were correlated with MT content. The increases in MT levels from the reference area Puchong Tengah compared to the polluted area Kampung Seri Kenangan were 3.4- and 3.8-fold for gills and livers, respectively. The results indicate that MT concentrations were tissue-specific, with the highest levels in the liver. Therefore, the liver can act as a tissue indicator in O. mossambicus in the study area.

Determination of Metal Levels in Thirteen Fish Species from Lakshadweep Sea

A bio-monitoring study was performed to investigate the concentration of certain metals (cadmium, cobalt, copper, iron, magnesium, manganese, nickel, lead and zinc) in gill, skin and muscle of thirteen demersal fish species of Agatti Coast of Lakshadweep Sea. All the metal concentrations in gill are higher than skin and muscle. Concentrations of toxic metals such as Cd (0.61±0.67μgg(-1) in Gerres longirostris), Mn (0.83±1.21μgg(-1) in Lutjanus fulvus) and Ni (0.56±0.83μgg(-1) in L. bengalensis) were well above the permissible limits suggested by World Health Organization and Food and Agricultural Organizations.

Growth and condition indices of juvenile turbot, Scophthalmus maximus, exposed to contaminated sediments: Effects of metallic and organic compounds

Since sediments have the potential to form associations with several classes of pollutants, they have been recognized as a possible and significant source of contamination for the benthic environment. Flatfish maintain a close association with sediments for food and cover, and are therefore more likely to be exposed to contaminated sediments, especially in coastal areas (e.g. nursery grounds). The assessment of these potential biological effects involves the use of adapted biomonitoring tools. The main objective of this study was to assess and compare the response of several physiological biomarkers measured on juvenile turbot ( Scophthalmus maximus) exposed to contaminated sediments. Sediments were collected from three stations in a harbour in northern France (Boulogne-sur-Mer), in an anthropogenic French estuary (the Seine), and in a reference site (exposed sandy beach of Wimereux). Unexposed lab-reared juvenile turbots were exposed to sediments for 7 and 21 days in laboratory conditions. Sediments were analysed for metals, PAH and PCB contamination. Several fish growth and condition indices were individually analysed in fish according to the chemical contaminant availability in sediment, the metal concentrations in gills and the estimation of PAH metabolites in their bile. Significant decreases in growth rates, morphometric index, RNA:DNA ratio and the lipid storage index, based on the ratio of the quantity of triacylglycerols on sterols (TAG:ST), were observed with increasing level of chemical contamination. This decrease in the fish's physiological status could be related to the significant increase of several metal concentrations in contaminated fish gills and the significant increase of PAH metabolites in bile. In a field situation, such a reduction in growth and energetic status of juvenile fish could dramatically decrease their over-winter survival in contaminated nursery grounds.

Genotoxic analysis in aquatic environment under influence of cyanobacteria, metal and radioactivity

The micronucleus (MN) and nuclear abnormality (NA) tests were employed to evaluate the genotoxic potential of the Lucrecia dam (RN, Brazil) located in a semi-arid region and influenced by crop irrigation and irregular rainfall. The analyses of these water samples demonstrated the presence of several cyanobacteria as well as metals and radioactivity. The Nile Tilapia ( Oreochromis niloticus) was used for micronucleus and nuclear abnormality assays and analysis of metal concentrations in gills and liver samples. Genotoxic assays in source water fish showed a significant increase in the frequency of nuclear damage (MN and NA) in relation to the negative control group. In conclusion, the results obtained with water surface and biological samples from the Lucrecia dam suggest that this important water resource contains a number of chemical and microbiological pollutants with genotoxic potential and that these substances may be compromising the species inhabiting this ecosystem. Particular care must be taken to prevent further degradation of this water supply. Capsule: A battery of assay was successfully applied to assess the water quality of Lucrecia dam from a Northeastern region of Brazil.

Exposure of brown trout ( Salmo trutta L.) to tunnel wash water runoff — Chemical characterisation and biological impact

Washing and cleaning of road tunnels are a routinely performed maintenance task, which generate significant amount of polluted wash-water runoff that normally is discharged to the nearest recipient. The present study was designed to quantify chemical contaminants (trace metals, hydrocarbons, PAH and detergents) in such wash water and assess the short term impact on brown trout ( Salmo trutta L.) based on in situ experiments. Selected endpoints were accumulation of trace metals in gills, haematological variables and hepatic mRNA transcription of five biomarkers reflecting defence against free radicals, trace metals, planar aromatic hydrocarbons and endocrine disruptions which were measured prior (− 3 h), during (1 and 3 h) and after the tunnel wash (14, 38 and 86 h). Our findings showed that the runoff water was highly polluted, but most of the contaminants were associated with particles which are normally considered biologically inert. In addition, high concentrations of calcium and dissolved organic carbon were identified in the wash water, thus reducing metal toxicity. However, compared to the control fish, a rapid accumulation of trace metals in gills was observed. This was immediately followed by a modest change in blood ions and glucose in exposed fish shortly after the exposure start. However, after 38–86 h post wash, gill metal concentrations, plasma ions and glucose levels recovered back to control levels. In contrast, the mRNA transcription of the CYP1A and the oxidative stress related biomarkers TRX and GCS did not increase until 14 h after the exposure start and this increase was still apparent when the experiment was terminated 86 h after the beginning of the tunnel wash. The triggering of the defence systems seemed to have successfully restored homeostasis of the physiological variables measured, but the fish still used energy for detoxification four days after the episode, measured as increased biomarker synthesis.

Combined use of environmental data and biomarkers in fish ( Liza aurata) inhabiting a eutrophic and metal-contaminated coastal system – Gills reflect environmental contamination

An investigative biomonitoring study was carried out in a eutrophic coastal system with a moderate contamination by metals (Óbidos lagoon, Portugal), combining the evaluation of exposure concentrations with metals accumulation and oxidative stress responses in gills of the golden grey mullet ( Liza aurata). Two contrasting seasons (winter and summer) were considered at three sites: Barrosa (BB) and Bom-Sucesso (BS) branches; Middle lagoon (ML). Data on the water column pointed to a higher metals and nutrients availability at BB that was reflected in the higher metal concentrations in gills, particularly in winter. Similarly, oxidative stress responses demonstrated a pro-oxidant challenge at BB (winter and summer), which was corroborated by an integrated biomarker response index (IBR). Metal concentrations in gills were higher in summer than winter, reflecting the increased environmental concentrations in combination with elevated metabolic rates. Catalase (CAT), glutathione-S-transferase (GST), total glutathione (GSH t) and lipid peroxidation (LPO) increases observed in winter at BB were related with metal accumulation, while summer enhancement of glutathione peroxidase (GPx), glutathione reductase (GR), GST and GSH t was associated with other stressors. Inter-site differences on the basis of IBR were more accentuated in winter. Gills can be considered as an important route of entry for contaminants and were demonstrated to reflect water contamination and are therefore useful in the context of environmental assessment.

Toxic effects of mining effluents on fish gills in a subarctic lake system in NW Russia

The mining company Karelian Pellet in northwestern Russia extracts iron ore and processes it locally into pellets. The production operations affect the environment in the form of air pollution and wastewater emissions to lakes downstream from the factory. The toxic effects of the mining effluents on gills of perch ( Perca fluviatilis) and roach ( Rutilus rutilus) were studied. In lakes close to the factory, heavy metal concentrations in gills were not high, even though the metal content in sediment was elevated. In fish gills the relative proportion of phosphatidylcholine was elevated and cholesterol reduced, while the histological structure of the gills was changed. The number of mucus cells, as well as the sizes and the lengths of open areas in the chloride cells, had increased in spring and summer. The hypertrophy of chloride cells is possibly caused by the increased ambient concentrations of K + and Li +. Changes in gill cholesterol and phospholipid proportions increase the fluidity of membranes and possibly strengthen their protective qualities, counterbalancing the adverse changes in chloride cell structure. The bioavailability and toxic effects of metals on fish are reduced by the hardness and high pH of water discharged by the mining plant.

Copper and Cadmium Binding to Fish Gills: Estimates of Metal–Gill Stability Constants and Modelling of Metal Accumulation

Fathead minnows (Pimephales promelas) were exposed to 17 μg Cu∙L−1or 6 μg Cd∙L−1in synthetic soft water in the presence of competing ligands. Measured gill metal concentrations correlated with free metal ion concentrations, not with total metal. Langmuir isotherms were used to calculate conditional metal–gill equilibrium constants and the number of binding sites for each metal. Log KCu-gillwas estimated to be 7.4 and the number of Cu binding sites on a set of gills (70 mg, wet weight) was ~2 × 10−10mol (~30 nmol∙g wet weight−1). Log KCd-gillwas ~8.6, and the number of Cd binding sites on minnow gills was ~2 × 10−10mol (~2 nmol∙g wet weight−1). Stability constants for H+and Ca interactions at metal–gill binding sites and for metal interactions with dissolved organic carbon (DOC) were estimated using these metal–gill constants. All stability constants were entered into the MSNEQL+aquatic chemistry program, to predict metal accumulation on fish gills using metal, DOC, and Ca concentrations, and water pH. Calculated metal accumulation on gills correlated well with measured gill metal concentrations and with LC50values. Our approach of inserting biological data into an aquatic chemistry program is useful for modelling and predicting metal accumulation on gills and therefore toxicity to fish.