Monitoring the effects of water pollution on Cyprinus carpio in Karakaya Dam Lake, Turkey

Tracking the microplastic pollution in the freshwater environments of southeastern Türkiye: Usage of Unio delicatus, Unio Terminalis and Dreissena polymorpha as bioindicators of microplastics

Microplastic (MP) pollution levels in aquatic environments raise concerns regarding the potential harm to biota and the environment. Mussel species are categorized as perfect bioindicator of pollutants due to their sessile lifestyle, and filter-feeding activity that also make them more prone to microplastic contamination. This study was designed to assess microplastic pollution levels in the soft tissues of dominant freshwater mussel species to understand general picture in microplastic contamination of the ambient environment. For that purpose, microplastic presence in the soft tissue of Unio delicatus (n:49), Unio Terminalis (n:31) and Dreissena polymorpha (n:82) was investigated. Including all examined specimens, mean microplastic abundance was found as 0.6 ± 0.8 items/ind, 0.2 ± 0.5 items/g ww with occurrence rate of 48 %. Reflecting global distribution, general morphological characteristics of MPs were fiber shape, blue colored and less than 500 μm in size. Fourier transform infrared (FTIR) spectroscopy identified the polymer type of MPs as polyethylene (40 %), polypropylene (47 %), and polystyrene (27 %). The results obtained in this study provide baseline information regarding microplastic contamination in freshwater environments and emphasize the need of protective measures.

Subacute toxicity and endocrine-disrupting effects of Fe2O3, ZnO, and CeO2 nanoparticles on amphibian metamorphosis

This study evaluated the potential toxic and endocrine-disrupting effects of sublethal concentrations of Fe2O3, CeO2 and ZnO nanoparticles (NPs) on amphibian metamorphosis. Tadpoles were exposed to several NPs concentrations, reaching a maximum of 1000 µg/L, for up to 21 days according to the amphibian metamorphosis assay (AMA). Some standard morphological parameters, such as developmental stage (DS), hind limb length (HLL), snout-to-vent length (SVL), wet body weight (WBW), and as well as post-exposure lethality were recorded in exposed organisms on days 7 and 21 of the bioassay. Furthermore, triiodothyronine (T3), thyroxine (T4) and malondialdehyde (MDA) levels and the activities of glutathione S-transferases (GST), glutathione reductase (GR), catalase (CAT), carboxylesterase (CaE), and acetylcholinesterase (AChE) were determined in exposed tadpoles as biomarkers. The results indicate that short-term exposure to Fe2O3 NPs leads to toxic effects, both exposure periods cause toxic effects and growth inhibition for ZnO NPs, while short-term exposure to CeO2 NPs results in toxic effects and long-term exposure causes endocrine-disrupting effects. The responses observed after exposure to the tested NPs during amphibian metamorphosis suggest that they may have ecotoxicological effects and their effects should be monitored through field studies.

Excess lifetime cancer risk due to ingestion of fish from a dam reservoir associated with a nuclear facility in Brazil

Fish from a Funil dam reservoir associated with a Nuclear Fuel Factory were sampled aiming to assess the radiological risk due to ingestion. Funil dam reservoir is a strategic site, once it receives effluent from the industrial complex that performs isotopic enrichment of uranium and conversion of UF6. The mean activity concentrations obtained for 40K, 226Ra, 228Ra and 228Th were 57.81, 0.41, 0.92 and 0.49 Bq·kg-1, respectively. Lifetime cancer risk was estimated in ∼10-5 and no action needs to be taken.

Heavy metal bioaccumulation triggers oxystress, genotoxicity and immunomodulation in head kidney macrophages of Channa punctatus Bloch

Studies on heavy metal induced toxicity have been conducted in many water bodies across the globe and such effects have been evaluated in various fish species. The present study was designed to determine the load of some heavy metals in select sites in Southern Assam, India, along with estimating their concentration in tissues of Channa punctatus Bloch. inhabiting those niches. The effect of heavy metals in oxystress generation, genotoxicity and subsequent immune response in fish was also evaluated. In all of these sites, the concentration of Hg, Cd, Pb and Cr were above the permissible ranges while their concentrations were several folds higher in the piscine tissues due to bioaccumulation and possible biomagnification. Kidney showed the highest metal pollution index followed by liver and gills. Generation of ROS was significantly elevated and that in turn triggered oxystress, as is evident from enhanced lipid peroxidation, protein carbonylation and respiratory burst activity. These were in association with the compromised antioxidant enzyme levels with concomitant damage to DNA as evident from Comet parameters. The innate immune potential was significantly impaired as evident from the compromised cell adhesion, phagocytosis, intracellular killing activity in head kidney macrophages (HKM) along with decreased release of nitric oxide (NO) and myeloperoxidase (MPO). Immunosuppression was further validated at protein levels where compromised release of cytokines viz. TNF-α, IL-1β, IL-6, IL-10 and IL-12 and cell signaling molecules iNOS and NF-κβ were noted. Thus the present study indicates genotoxicity along with a compromise in immune status of Channa punctatus Bloch. living in a habitat laden with heavy metals.

Ammonia Toxicity in the Bighead Carp (Aristichthys nobilis): Hematology, Antioxidation, Immunity, Inflammation and Stress

Ammonia is one of the main environmental pollutants that affect the survival and growth of fish. The toxic effects on blood biochemistry, oxidative stress, immunity, and stress response of bighead carp (Aristichthys nobilis) under ammonia exposure were studied. Bighead carp were exposed to total ammonia nitrogen (TAN) concentrations of 0 mg/L, 3.955 mg/L, 7.91 mg/L, 11.865 mg/L, and 15.82 mg/L for 96 h. The results showed that ammonia exposure significantly reduced hemoglobin, hematocrit, red blood cell, white blood cell count, and platelet count and significantly increased the plasma calcium level of carp. Serum total protein, albumin, glucose, aspartate aminotransferase, and alanine aminotransferase changed significantly after ammonia exposure. Ammonia exposure can induce intracellular reactive oxygen species (ROS), and the gene expression of antioxidant enzymes (Mn-SOD, CAT, and GPx) increases at the initial stage of ammonia exposure, while MDA accumulates and antioxidant enzyme activity decreases after ammonia stress. Ammonia poisoning changes the gene expression of inflammatory cytokines; promotes the gene expression of inflammatory cytokines TNF-α, IL-6, IL-12, and IL-1β; and inhibits IL-10. Furthermore, ammonia exposure led to increases in stress indexes such as cortisol, blood glucose, adrenaline, and T3, and increases in heat shock protein 70 and heat shock protein 90 content and gene expression. Ammonia exposure caused oxidative stress, immunosuppression, inflammation, and a stress reaction in bighead carp.

Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) occurrence in Sparus aurata exposed to microplastic enriched diets in aquaculture facilities

Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) are highly stable and bioaccumulative, and microplastics (MPs; plastics <5 mm) are ubiquitous in the marine environment. In this study we report the levels of a selection of pollutants in liver and muscle of juvenile gilthead seabream (Sparus aurata) exposed to virgin and weathered MP enriched diets during three months and followed by one month of MP depuration. In general, a major concentration of pollutants in liver was observed. According to OCPs, total DDTs was two or three times higher in liver. Levels in muscle suffer higher variability between treatments and sampling periods. The MP index was negatively correlated to HCB and positively to p,p'DDT in liver. Levels of pollutants are correlated to biological parameters such as total size and total weight. Our results suggest that the bioaccumulation is subjected to the molecular structure of the pollutants and that MPs are correlated with the detoxification system.

A morpho-histopathological study in the digestive tract of three fish species influenced with heavy metal pollution

In this study, the digestive tract of three freshwater fish species (Capoeta capoeta, Alburnus mossulensis and Squalius cephalus) was examined using a morpo-histopathological technique. Sediment and fish samples were taken from selected four stations in the Karasu River (Erzurum, Turkey) between June and September in 2015-2016. In water and sediment samples, the concentrations of some metals (Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Sr and Pb) were determined. Histopathological changes in digestive tract were determined by histopathological alterations index (HAI). Intestinal coefficient (IC) and condition factor (CF), which are general indicators of exposure to environmental stress, were calculated for each fish. The highest CF was observed at the least contaminated site of the gradient. C. capoeta showed the highest values of IC among species. The detected abnormalities were infiltration, swelling, gastric degenerations, vacuolization, congestion, epithelial degenerations, hyperplasia, fibrosis and fusion at polluted site fish. It was also observed that the HAI and IC values in fish varied significantly from site to site. The results showed that the content of heavy metals in the river water and sediment may affect the health status of the fish species.

Impact of nitrite exposure on plasma biochemical parameters and immune-related responses in Takifugu rubripes

Nitrite is a major environmental pollutant in aquatic environments that negatively affects aquatic species. In this study, we investigated the impact of nitrite exposure on plasma biochemical parameters and immune responses in Takifugu rubripes. Fish were exposed to various concentrations of nitrite (0, 0.5, 1, 3, and 6 mM) for 96 h. After 0, 12, 24, 48, and 96 h of exposure, fish blood samples were collected to assay the levels of total protein (TP), albumin (Alb), glutamic-oxaloacetic transaminase (GOT), glutamic-pyruvic transaminase (ALT), complement C3 (C3), complement C4 (C4), immunoglobulin (IgM), and lysozyme activity (LZM). The gills were sampled to analyze the mRNA levels of heat shock protein 70 (hsp70), heat shock protein 90 (hsp90), tumor necrosis factor α (tnf-α), B-cell activating factor (baff), interleukin-6 (il-6), and interleukin-12 (il-12). Levels of GOT, ALT, C3, and C4 were significantly enhanced in the high nitrite concentration group (3 and 6 mM), whereas those of TP, Alb, LZM, and IgM decreased significantly with the same treatments. Nitrite significantly upregulated hsp70, hsp90, tnf-α, il-6, il-12, and baff mRNA levels after 96 h of exposure. These results indicated that nitrite exposure altered the blood physiological status and immune system response, resulting in dysfunction and immunotoxicity in T. rubripes. Furthermore, our results reveal the possible mechanism of aquatic-nitrite-induced toxicity in fish.

A multibiomarker approach for evaluating environmental contamination: Common carp (Cyprinus carpio) transplanted along a gradient of metal pollution

Environmental monitoring and risk assessment approaches which include a more holistic view on the effects of pollutants on biota are increasingly sought by regulators and policy makers. Therefore, caged carp juveniles (Cyprinus carpio) were transplanted for 7 weeks along a known Cd and Zn pollution gradient. Metal (Cu, Cd and Zn) accumulation in gill and liver tissue and effect biomarkers (growth, condition factor (CF), hepatosomatic index (HSI), oxygen consumption, swimming capacity, Na⁺/K⁺-ATPase activity (NKA) and metallothionein (MT) levels) were compared. Up to 10-fold higher cadmium concentrations were measured in the gills of the fish at the most polluted locations compared to the laboratory control fish. Similarly, cadmium concentrations in liver tissues of field-exposed fish were significantly higher than those measured in laboratory control fish. Cu and Zn concentrations in the gills were not significantly different between field-exposed and control organisms, whereas higher levels in liver tissues were measured in carps deployed in some locations. Effects on liver MT levels were up to 10 times greater for organisms exposed to the field, whereas no clear effect of the metal exposure on NKA in the gill tissue was observed. A decrease in muscle glycogen stores was observed for all organisms deployed in the field, while liver glycogen levels decreased only in fish exposed to two of the 5 sites compared to the laboratory control fish. Additionally, significant drops in liver protein- and lipid stores were observed. No effect on oxygen consumption rates and swimming capacity was observed. The CF and HSI of caged fish reflected the pollution gradient in the river and considerable loss of weight was observed for fish transplanted in the most polluted site. Overall, this active biomonitoring study successfully revealed differences in metal accumulation, physiological and organismal endpoints as a direct consequence of field exposure.

Effects of Multi-Component Mixtures from Sewage Treatment Plant Effluent on Common Carp (Cyprinus carpio) under Fully Realistic Condition

This study characterized changes in biomarker responses in common carp (Cyprinus carpio) upon exposure to effluent water discharged from a sewage treatment plant (STP) under real conditions. Fish were exposed to contamination in Cezarka pond, which receives all of its water input from the STP in the town of Vodnany, Czech Republic. Five sampling events were performed at day 0, 30, 90, 180, and 360 starting in April 2015. In total, 62 pharmaceutical and personal care products (PPCPs) were detected in the polar organic chemical integrative sampler. Compared to a control pond, the total concentration of PPCPs was 45, 16, 7, and 7 times higher in Cezarka pond at day 30, 90, 180, and 360, respectively. The result of oxidative stress and antioxidant enzyme biomarkers indicated alterations in the liver and intestine tissues of fish from Cezarka pond at day 30 and 360, respectively. High plasma vitellogenin levels were observed in both exposed females (180 and 360 days) and males (360 days) compared with their respective controls. However, only exposed female fish had higher vitellogenin mRNA expression than the control fish in these periods. Exposed female fish showed irregular structure of the ovary with scattered oocytes, which further developed to a vitellogenic stage at day 360. Low white blood cell levels were indicated in all exposed fish. Despite numerous alterations in exposed fish, favorable ecological conditions including high availability of food resulted in a better overall condition of the exposed fish after 1 year of exposure compared to the controls.

Contaminant accumulation and biological responses in Atlantic cod (Gadus morhua) caged at a capped waste disposal site in Kollevåg, Western Norway

The aim of this study was to assess whether fish in Kollevåg, a sheltered bay on the western coast of Norway, previously utilized as a waste disposal site, could be affected by environmental contaminants leaking from the waste. Farmed, juvenile Atlantic cod (Gadus morhua) were caged for six weeks at three different locations in Kollevåg bay and at one reference location. Sediments and cod samples (bile and liver) were analyzed for polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), brominated flame retardants (BFRs), per-and polyfluoroalkyl substances (PFASs) and polycyclic aromatic hydrocarbon (PAH) metabolites, revealing a contamination gradient at the four stations. Furthermore, hepatosomatic index (HSI) and Fulton's condition factor (CF) were significantly lower in cod caged closest to the disposal site. Levels and activities of biomarker proteins, such as vitellogenin (Vtg), metallothionein (Mt), and biotransformation and oxidative stress enzymes, including cytochrome P450 1a and 3a (Cyp1a, Cyp3a), glutathione s-transferase (Gst) and catalase (Cat), were quantified in blood plasma and liver tissue. Hepatic Cat and Gst activities were significantly reduced in cod caged at the innermost stations in Kollevåg, indicating modulation of oxidative stress responses. However, these results contrasted with reduced hepatic lipid peroxidation. Significant increases in transcript levels were observed for genes involved in lipid metabolism (fasn and acly) in cod liver, while transcript levels of ovarian steroidogenic enzyme genes such as p450scc, cyp19, 3β-hsd and 20β-hsd showed significant station-dependent increases. Cyp1a and Vtg protein levels were however not significantly altered in cod caged in Kollevåg. Plasma levels of estradiol (E2) and testosterone (T) were determined by enzyme immunoassay (EIA) and showed elevated E2 levels, but only at the innermost station. We conclude that the bay of Kollevåg did not fullfill adequate environmental condition based on environmental quality standards (EQSs) for chemicals in coastal waters. Following a six weeks caging period, environmental contaminants accumulated in cod tissues and effects were observed on biomarker responses, especially those involved in reproductive processes in cod ovary.

Effects of waterborne nitrite on hematological parameters and stress indicators in olive flounders, Paralichthys olivaceus, raised in bio-floc and seawater

Juvenile olive flounders, Paralichthys olivaceus (mean weight 2.69 ± 0.31 g), were raised in bio-floc and seawater for six months, these P. olivaceus (mean weight 280.1 ± 10.5 g, mean length 28.37 ± 2.3 cm) were exposed to different concentrations of waterborne nitrite (0, 25, 50, 100, and 200 mg NO₂^-/L) for 7 days. None of the P. olivaceus individuals exposed to bio-floc and seawater containing waterborne nitrite concentrations of 200 mg/L for 7 days survived. Hematological parameters (hemoglobin and hematocrit) were significantly reduced by nitrite exposure. Regarding plasma components, the concentrations of glucose, glutamic oxalate transaminase (GOT), and glutamic pyruvate transaminase (GPT) increased significantly in response to nitrite exposure, whereas cholesterol concentrations significantly decreased. Stress indicators, including concentrations of plasma glucose, cortisol, and liver and gill concentrations of heat shock protein 70 (HSP70) were significantly increased by nitrite exposure. The results of the study indicate that nitrite exposure affected the hematological parameters and stress indicators of P. olivaceus raised in bio-floc and seawater, and these changes were more prominent in the P. olivaceus raised in seawater than those raised in bio-floc.

Induction of EROD and BFCOD activities in tissues of barbel (Barbus callensis) from a water reservoir in Algeria

EROD and BFCOD activities were measured in liver and gills of barbel (Barbus callensis, a native North African species) captured at Beni Haroun lake, the most important water reservoir in Algeria. This lake receives wastewater from different origins. Thus, we assessed the level of pollution through the induction of detoxification activities in tissues of barbel, evaluating simultaneously the suitability of this species to be used as a sentinel. Fish were collected between March 2015 and January 2016 at three locations taking into account the pollution sources and accessibility. In liver, EROD and BFCOD showed the highest induction in October specially in the location of the dam that received pollutants. In gills, only EROD, but not BFCOD, activity was detected. Maximal EROD induction was noted in samples from January. Fish cell lines (RTG-2 and PLHC-1) were exposed to sediments extracts collected at Beni Haroun lake and enzyme activities (EROD and BFCOD, respectively) were measured. Sediment extracts did not induce BFCOD activity. The EROD induction observed in RTG-2 cells was in line with the results observed in fish tissues. Our results suggest that the lake is at risk from pollution and that Barbus callensis is a good sentinel species.

Global patterns and clines in the growth of common carp Cyprinus carpio

This review provides a meta-analytical assessment of the global patterns and clines in the growth of Cyprinus carpio as measured by length-at-age (L_t ) or von Bertalanffy growth function (VBGF) parameters, mass-length relationship (W-L_t ) and condition factor, based on literature data. In total, 284 studies were retrieved spanning 91 years of research and carried out on 381 waterbodies-locations in 50 countries in all five continents. Although native C. carpio achieved larger (asymptotic) size relative to its non-native counterpart, the latter grew faster during the first 7 years of life. Lentic populations (especially in natural lakes) also achieved larger sizes relative to lotic ones and the same was true for populations in cold and temperate v. arid climates. Unlike previous studies (on much more restricted datasets), only weak latitudinal clines in instantaneous growth rate, L_t at age 3 and mortality were observed globally and this was probably due to the presence of counter-gradient growth variation at all representative age classes (i.e. 1-10 years). Slightly negative allometry was revealed by the W-L_t and the related form factor tended to distinguish the more elongated and torpedo-shaped body typical of the wild form from the deeper body of feral-domesticated C. carpio. Existing population dynamics models for C. carpio will benefit from the comprehensive range of waterbody type × climate class-specific VBGF parameters provided in the present study; whereas, more studies are needed on the species' growth in tropical regions and to unravel the possibility of confounding effects on age estimation due to both historical and methodological reasons.

Haematological and immune upshots in Clarias batrachus exposed to dimethoate and defying response of dietary ascorbic acid

Dimethoate (DM) is an organophosphate insecticide used worldwide in agriculture, household practices. It has resulted in a series of environmental and toxicological impacts on non-target aquatic organisms. The present study investigated the potential ameliorative effects of dietary ascorbic acid (AA) against dimethoate toxicity in the haematological and immune parameters in Clarias batrachus. The experiment included group A (basal diet), group B (basal diet with 1.245 mg L^-1 DM) and group C (200 mg kg^-1 AA with 1.245 mg L^-1 DM) were fed for 8 weeks. Samples were collected at the end of every week in each group and estimated haematological profile (red blood cell count, haemoglobin concentration, haematocrit %, albumin and globulin levels), erythrocyte indices (mean corpuscular volume, mean corpuscular haemoglobin, and mean corpuscular haemoglobin concentration), biochemical parameters (AA levels in blood and liver, total proteins, glucose, serum triglycerides, creatinine levels and glutamic oxaloacetate, glutamic pyruvate transaminase (GOT, GPT)) and immune responses (white blood cell count, serum IgM levels and activities of nitroblue tetrazolium, lysozyme and peroxidase) of the fish. Fish fed with ascorbic acid, showed red blood cell, haemoglobin, haematocrit, erythrocyte indices, albumin, globulin and serum triglycerides, creatinine, plasma total proteins, glucose levels are not differed (≤10%) from control. Likewise, ascorbic acid maintains optimal levels in activities of GOT, GPT, nitroblue tetrazolium, lysozyme and peroxidase, white blood cells and serum IgM levels. Further studies are needed to ascertain how ascorbic acid improves the innate and humoral immune system of the fish and the mechanisms involved.

Multibiomarker toxicity characterization of uranium mine drainages to the fish Carassius auratus

The release of acidic effluents, naturally enriched in metals and radionuclides, is the main legacy of uranium mines. Generally, metals dissolved by these acidic effluents can cause significant alterations in exposed organisms, with distinct toxicological outcomes. In this study, 72 individuals of the freshwater fish species Carassius auratus were exposed in situ for different periods (8, 16, 24, and 48 h) to water from a pond (treatment pond (TP)) with a chemically treated effluent and a reference pond (PRP), in the vicinity of the Cunha Baixa uranium mine (Portugal). Comparing the water of the two ponds, the PRP pond was characterized by higher pH and oxygen values and lower conductivity and hardness values. Regarding total metal concentrations, among others, magnesium (56,000 μg/L), sodium (17,400 μg/L), zinc (86 μg/L), manganese (6340 μg/L), and uranium (1380 μg/L) concentrations in the TP pond were above the values obtained for the PRP pond. The values of manganese and uranium exceeded the values of quality criteria established for surface waters for cyprinids and for irrigation purposes. After exposure to pond water, significant differences were recorded for several biomarkers: (i) between ponds for acetylcholinesterase (AChE) with higher activities for animals from the PRP and glutathione-S-transferase (GST) activities that were particularly enhanced in animals from the TP pond; (ii) between ponds and exposure periods for lactate dehydrogenase (LDH) activity, since organisms from PRP pond presented always higher values than those from the TP pond, and among these, organisms exposed for the longer period presented a further depression in LDH activity; and (iii) between exposure periods for erythrocyte micronucleus. GSTs and LDH were the most sensitive biomarkers within the timeframe of the in situ assay performed. Despite the alleged efficacy of the chemical treatment (evidenced by a significantly lower pH), some metals persisted in the treated effluent (TP pond), potentially contributing to the induction of oxidative stress or increased conjugation metabolic activity in fish.

Bioaccumulation of metals in common carp (Cyprinus carpio L.) from water bodies of Anatolia (Turkey): a review with implications for fisheries and human food consumption

Although fish is widely consumed by humans for its nutritional properties, accumulation of heavy metals can pose serious health hazards. Widespread common carp Cyprinus carpio is cultured worldwide and represents an economically important species for fisheries in several countries. These include Turkey, where C. carpio often makes for a large part of the sales of the locally marketed fish and also for a traditional dish. This study provides a review of bioaccumulation of metals in tissues of C. carpio from water bodies of Anatolia and also includes reference to worldwide studies. From 42 water bodies across the region, 27 metals in total were studied, of which Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn were the most widely analysed, mainly in the muscle, liver and gill tissues. Amongst the potentially toxic metals, Cd, Cr and Pb occurred in several water bodies at concentrations not only above maximum allowed limits but also higher relative to other water bodies worldwide, even though As, Hg and Ni were also sometimes present at potentially hazardous concentrations. The essential metals Cu, Fe, Mn, Se and Zn were detected at various concentrations, with the latter two occasionally above limit. All water bodies flagged as having especially critical (i.e. above limit) concentrations of toxic metals supported C. carpio fisheries from highly populated regions, raising concern about food safety and calling for preventative measures. Given the significantly lower bioaccumulation levels in the muscle relative to the liver and gill tissues, it is suggested that consumption of C. carpio as fillets may be safer than after processing into e.g. meat balls and sausages. The limits of 1.0 μg/g for Cr and 1.15 μg/g for Se, currently lacking from the Turkish food safety legislation, are proposed, and it is suggested that a similar meta-analytical approach as adopted in this study may benefit other countries where C. carpio represents an important fisheries resource.

The chromium accumulation and its physiological effects in juvenile rockfish, Sebastes schlegelii, exposed to different levels of dietary chromium (Cr(6+)) concentrations

Juvenile rockfish (mean length 13.7±1.7 cm, and mean weight 55.6±4.8 g) were exposed for 4 weeks with the different levels of dietary chromium (Cr(6+)) at 0, 30, 60, 120 and 240 mg/kg. The profile of chromium in the tissues of rockfish is dependent on the exposure periods and chromium concentration. After 4 weeks, the order of chromium accumulation in tissues was liver>kidney>spleen>intestine>gill>muscle. The dietary chromium exposure decreased the growth rate and hepatosomatic index of rockfish. The major hematological findings were significant decrease in the red blood cell (RBC) count, hematocrit (Ht) value, and hemoglobin (Hb) concentration exposed to ≥120 mg/kg chromium concentrations. The dietary chromium exposure (≥120 mg/kg) led to notable increase in glucose, cholesterol, glutamic oxalate transaminase (GOT), and glutamic pyruvate transaminase (GPT) in plasma, whereas there was no considerable change in calcium, magnesium, total protein, and alkaline phosphatase (ALP). The results indicated that the dietary chromium exposure to rockfish can induce significant chromium accumulation in the specific tissues, inhibition of growth, and hematological alterations.

Low concentrations of metal mixture exposures have adverse effects on selected biomarkers of Xenopus laevis tadpoles

Polluted ecosystems may contain mixtures of metals, such that the combinations of metals, even in low concentrations, may cause adverse effects. In the present study, we focused on toxic effects of mixtures of selected metals, the LC50 values, and also their safety limit in aquatic systems imposed by the European legislation using a model organism. Xenopus laevis tadpoles were used as test organisms. They were exposed to metals or their combinations due to 96-h LC50 values. Glutathione S-transferase (GST), glutathione reductase (GR), acetylcholinesterase (AChE), carboxylesterase (CaE), glutathione peroxidase (GPx), and catalase (CAT) levels were evaluated. Metallothionein concentrations were also determined. The LC50s for Cd, Pb, and Cu were calculated as 5.81mg AI/L, 123.05mg AI/L, and 0.85mg AI/L, respectively. Low lethality ratios were observed with unary exposure of each metal in lower concentrations. Double or triple combinations of LC50 and LC50/2 concentrations caused 100% lethality with Cd+Cu and Pb+Cd+Cu mixtures, while the Pb+Cu mixture also caused high lethal ratios. The selected enzyme activities were significantly affected by metals or mixtures, and dose-related effects were determined. The metallothionein levels generally increased as related to concentration in unary metals and mixtures. Acceptable limit values of unary metals and mixtures did not significantly change metallothionein levels. The results suggest that oxidative stress-related mechanisms are involved in the toxicity induced by selected metals with combinations of very low concentrations.

Comparative assessment of in vitro and in vivo toxicity of azinphos methyl and its commercial formulation

The toxic effects of Gusathion (GUS), which is a commercial organophosphate (OP) pesticide, and also its active ingredient, azinphos methyl (AzM), are evaluated comparatively with in vitro and in vivo studies. Initially, the 96-h LC50 values of AzM and GUS were estimated for two different life stages of Xenopus laevis, embryos, and tadpoles. The actual AzM concentrations in exposure media were monitored by high-performance liquid chromatography. Also, the sub-lethal effects of these compounds to tadpoles were determined 24 h later at exposure concentrations of 0.1 and 1 mg/L using selected biomarker enzymes such as acetylcholinesterase (AChE), carboxylesterase (CaE), glutathione S-transferase (GST), glutathione reductase, lactate dehydrogenase, and aspartate aminotrasferase. Differences in AChE inhibition capacities of AzM and GUS were evaluated under in vitro conditions between frogs and fish in the second part of this study. The AChE activities in a pure electrical eel AChE solution and in brain homogenates of adult Cyprinus carpio, Pelophylax ridibundus, and X. laevis were assayed after in vitro exposure to 0.05, 0.5, 5, and 50 mg/L concentrations of AzM and GUS. According to in vivo studies AChE, CaE and GST are important biomarkers of the effect of OP exposure while CaE may be more effective in short-term, low-concentration exposures. The results of in vitro studies showed that amphibian brain AChEs were relatively more resistant to OP exposure than fish AChEs. The resistance may be the cause of the lower toxicity/lethality of OP compounds to amphibians than to fish.

Monitoring and assessment of environmental disturbance on natural Gambusia affinis populations--histopathological analysis

Physiological investigations are often used to assess the toxic effects of aquatic pollutants in fish and to establish criteria for water quality. In the present study, we tend to investigate the growth performance, skeletal abnormalities, and histological alterations noticed in three natural populations of the mosquitofish Gambusia affinis captured from three estuary sites. The analysis of growth performance demonstrated that the studied populations showed different growth patterns. Additionally, various types of skeletal deformities were observed, and the most commonly affected were the hemal and pre-hemal regions of fishes. For the histological study, gills, liver, and kidney tissues were selected for field monitoring. The major alterations observed in gill tissues were partial fusion of adjacent secondary lamellae, hypertrophy of epithelial cells, and disorganization of pillar cells in many areas of the secondary lamellae. In the liver, significant desquamation of tissues, congestion of the central hepatic vein, and hypertrophy of hepatocytes were noticed. For the kidney tissue, the frequencies of histological alterations showed a significant difference between the studied sites. Moreover, the histological aberrations consisted mainly in glomerule alteration and vacuolation of tubular epithelial cells. Taken together, these data support the hypothesis that the physiological alterations noticed in the present investigation are indicators of sensitivity towards environmental disturbance.

The lead accumulation and hematological findings in juvenile rock fish Sebastes schlegelii exposed to the dietary lead (II) concentrations

Juvenile rockfish (mean length 14.2 ± 1.9 cm, and mean weight 57.3 ± 5.2g) were exposed for 4 weeks with the different levels of dietary lead (Pb(2+)) at 0, 30, 60, 120 and 240 mg/L. The exposure concentration and period of Pb have induced significant amount of it the specific tissues of rockfish. The highest Pb accumulation was observed in the kidney tissue by the dietary lead exposure. The growth rate and hepatosomatic index were considerably inhibited over 120 mg/kg. The hematological parameters such as red blood cell (RBC) counts, hematocrit (Ht) value, and hemoglobin (Hb) concentration were significantly decreased over 60 mg/kg Pb concentration. In the inorganic components, the values of calcium and magnesium in plasma were significantly decreased. The glucose and cholesterol values were notably increased, whereas total protein was decreased. The enzyme components, glutamic oxalate transaminase (GOT) and glutamic pyruvate transaminase (GPT), were significantly elevated by the dietary lead exposure, but no change was observed in alkaline phosphatase (ALP).

Temporal distribution of accumulated metal mixtures in two feral fish species and the relation with condition metrics and community structure

The present study investigated temporal influences on metal distribution in gudgeon (Gobio gobio) and roach (Rutilus rutilus), and its relation to condition metrics and fish community structure. Fish communities were sampled in two seasons (autumn and spring) during two successive years and the Index of Biotic Integrity (IBI) was calculated. Cadmium, Cu, Pb, Zn and As concentrations were measured in gill, liver, kidney and muscle, and condition factor (CF) and hepatosomatic index (HSI) were measured. Cadmium (max. 39.0 μg g(-1) dw) and Zn (max 2502 μg g(-1) dw) were most strongly stored in kidney and liver and periodical influences on metal accumulation were observed. CF appeared to be a stable metric related to accumulated metal-mixtures and was best related to hepatic levels, while the HSI was less useful. Relations between single metal accumulation and IBI were influenced by sample period, however, when taking into account multiple metals periodical influences disappeared.

Haematological and biochemical parameters and tissue accumulations of cadmium in Oreochromis niloticus exposed to various concentrations of cadmium chloride

Oreochromis niloticus, weighing 36.45 ± 1.12 g were exposed to 10%, 20% and 30% of the LC₅₀ of CdCl₂ which represents treatments (T1)1.68, (T2)3.36 and (T3)5.03 mg/l, respectively, for a period of 10, 20 and 30 days. It was found that, compared to a control group reading of 0.19 ± 0.03 μg/g dry weight, accumulation of Cd in the gills was significantly (p < 0.05) increased in samples ranging between 7.64 ± 0.86 and 61.73 ± 0.82 μg/g dry weight from T1 at 10 days to T3 at 30 days. The accumulation of Cd in the liver, meanwhile, was also observed to significantly increase (p < 0.05) with increasing time and concentrations with results ranging between 3.21 ± 0.12 and 181.61 ± 1.32 compared to the control group results of 0.29 ± 0.04 μg/g dry weight. Although muscles exhibited lower levels of accumulation than the gills and liver they still showed the same pattern of increase compared to the control group, with a significant difference ranging between 0.32 ± 0.02 and 2.16 ± 0.08 compared to the control group results of 0.03 ± 0.001 μg/g dry weight. Also, haematological parameters such as red blood cells (RBCs), haemoglobin (Hb) and haematocrit (Hct) were reduced in fish exposed to Cd at all periods, with significant differences (p < 0.05). Plasma glucose concentration showed a significant increase. Total protein levels of fish showed a significant reduction (p > 0.05) for all exposed treatments. Also, the total lipid level increased significantly as fish were exposed to increasing cadmium concentrations, compared to control fish. Finally, the activities of aspartate aminotransferase (AST IU/l) and alanine aminotransferase (ALT IU/l) showed a significant increase (p < 0.05) with increasing time and concentrations.

Effects of fish size on the response of antioxidant systems of Oreochromis niloticus following metal exposures

The size of a fish is an important factor in its physiology, and metal uptake is affected by animal physiology. In this study, small and large tilapias (Oreochromis niloticus) differing approximately twofold in length and fivefold in weight were compared for their antioxidant response. Both groups were exposed to Cu or Cr (1.0 μg/mL) in a freshwater (-80 mg CaCO3/L, conductivity 1.77 mS/cm) using 2 exposure protocols (20 μM for 48 h and 10 μM for 6 days). Following the exposures, the antioxidant enzyme activities (superoxide dismutase, SOD; catalase, CAT; glutathione peroxidase, GPX; glutathione reductase, GR and glutathione S-transferase, GST) and glutathione (GSH) levels were measured in the liver of fish. Results showed that small fish was affected from exposure conditions much more than large ones as their antioxidant parameters significantly decreased even in controls. Metal exposures of small fish caused significant increases in SOD and CAT activity in acute Cu or Cr exposures. Subchronic Cr exposure of small fish also caused significant increases in CAT, GPx and GST activities, while there was no significant change in Cu-exposed ones. Large fish, however, showed different antioxidant responses as their levels mostly decreased. This study demonstrated that the response of antioxidant system in the liver of tilapia varied in relation to fish sizes and emphasized using different size groups in environmental monitoring and also in evaluation of fish biomarkers.

Biomarker responses in caged carp (Cyprinuscarpio) and native collected fish (Leporinus obtusidens) in the Río de la Plata Estuary, Argentina

Punta Lara is located in the Río de la Plata estuary near industrial areas contaminated mainly by organic pollutants. In this work, the responses and status of hepatic biomarkers were studied in juvenile carp (Cyprinus carpio) by means of a 21-day field exposure in cages and collection of juvenile native fish (Leporinus obtusidens) at Punta Lara. The analyzed hepatic biomarkers were: enzymatic activity of glutathione-S-transferase (GST), catalase (CAT) and superoxide dismutase (SOD), lipid peroxidation level using the thiobarbituric acid reaction (TBARS), and CYP1A protein expression, condition factor (CF) and liver somatic (LSI) index. Taking into account oxidative stress responses, SOD activity was increased in both species, while CAT was increased in C. carpio and decreased in L. obtusidens; TBARS levels indicated that oxidative damage was possibly exerted only in L. obtusidens. Biotransformation responses mediated by CYP1A were observed in both species, while GST activity was induced mainly in carps. Considering morphometric indices, CF and LSI were significantly increased in carps while CF decreased in native species. The anthropogenic pollution detected in this study in Punta Lara was associated with differences in biomarkers on both fish species, although a different pattern of response was observed.

The effect of glyphosate, its metabolites and impurities on erythrocyte acetylcholinesterase activity

Glyphosate [N-(phosphonomethyl)glycine] is used all over the world to protect agricultural and horticultural crops. According to initial reports, glyphosate has been considered to be safe for humans and animals; nevertheless, recent investigations had proven its toxicity. Extensive use of glyphosate and the conviction of its low toxicity leads to a situation in which it is used in excessive amounts in agriculture. That is why, we have investigated the effect of the most commonly used pesticide: glyphosate, its metabolites and impurities on acetylcholinesterase (AChE) activity (in vitro) in human erythrocytes, which is biochemically similar to acetylcholinesterase present in neural synapses. The analysis of noxious effects of metabolites and impurities of pesticides seems to be very important to evaluate toxicological risk that is associated with the effect of pesticide formulations (requirement of the EU regulations 1107/200/EC). The erythrocytes were incubated with xenobiotics at concentrations range from 0.01 to 5 mM for 1 and 4 h. Statistically significant decrease in AChE activity (about 20%) was observed only at high concentrations of the compounds (0.25-5 mM), which enter body only as a result of acute poisoning. There were no statistically significant differences in the effect of the investigated compounds, while the changes caused by them were similar after 1 and 4 h incubation. The investigated metabolites and impurities did not cause stronger changes in AChE activity than glyphosate itself. It may be concluded that the compounds studied (used in the concentrations that are usually determined in the environment) do not disturb function of human erythrocyte acetylcholinesterase.

Heavy metals levels in fish from aquaculture farms and risk assessment in Lhasa, Tibetan Autonomous Region of China

Fish is consumed as a common food by humans due to its nutritional and therapeutic benefits. However, they can accumulate toxic chemicals (such as heavy metals, persistent organic pollutants) from water and food chain. Very few studies have been investigated on heavy metal contents in fish from Tibetan Autonomous Region of China. In order to study heavy metals levels in fish from aquaculture farms and evaluate the risk that human consume fish in this area, we collected four types of aquaculture fish species (6 big-head carps, 5 grass carps, 5 carps and 5 tilapias) from fisheries around Lhasa city in this study. 9 heavy metals (Cr, As, Cd, Pb, Cu, Ba, Co, Mn and V) in different tissues of fish were determined by an inductively coupled plasma mass spectrometer. Cr, Ba, Co, Mn and V could easily accumulate in the gill, and Cu was detected in the hearts of all the fishes. Toxic metal (As, Cd and Pb) contents were higher in the liver than those in other tissues, heavy metal levels were the lowest in the muscle among all tissues. Most of heavy metal concentrations in the tilapia tissues were higher than those in other fish tissues, especially arsenic. Arsenic content in the tilapia samples was ~2-4 times higher than the maximum levels (MLs) of contaminants in the national standard, and other metals were all lower than the MLs. Compared the estimated daily intake of heavy metals through fish consumption with tolerable daily intakes recommended by FAO, the metals daily intake of As, Cd and Pb from fish consumption might not pose serious health risk to the local inhabitants. It is therefore necessary to determine the dose level for human, which is considered to be taken daily over a lifetime without adverse effects.

Use of acetylcholinesterase, glutathione S-transferase and cytochrome P450 1A1 in Capoeta umbla as biomarkers for monitoring of pollution in Uzuncayir Dam Lake (Tunceli, Turkey)

Uzuncayir Dam Lake is one of the most important water bodies in Tunceli. It is polluted by domestic wastewaters together with natural contamination and pesticides, which have had cumulatively negative effects. This study analyzes the effects of pollution by using the fish species, Capoeta umbla as a sentinel species, with a biomarker approach. The approach comprehends a general biomarker of individual fish health, the condition factor and specific biomarkers of contaminant exposure such as glutathione S-transferase (GST) and cytochrome P450 1A1 (CYP1A1) and acetylcholinesterase (AChE) activity. The general water physico-chemical parameters were measured at each sampling sites during each fish-sampling period. Strong seasonal and locational variations were observed among selected markers. In conclusion, the multibiomarker approach used in the present study clearly revealed differences in the fish health among reference and potentially contaminated sites. The study shows that changes of biomarkers such as acetylcholinesterase, glutathione S-transferase and cytochrome P450 1A1 might be useful for the assessment of environmental contamination in the Uzuncayir Dam Lake (Tunceli, Turkey).

Alteration in certain enzymological parameters of an Indian major carp, Cirrhinus mrigala exposed to short- and long-term exposure of clofibric acid and diclofenac

The extensive use of pharmaceuticals in human and veterinary medicine may enter the aquatic environment and pose a serious threat to non-target aquatic organisms like fish. In this study, Indian major carp Cirrhinus mrigala was exposed to different concentrations (1, 10 and 100 μg L⁻¹) of most commonly used pharmaceutical drugs clofibric acid (CA) and diclofenac (DCF) to evaluate its impacts on certain enzymological parameters during short- and long-term exposures. During short-term (96 h) exposure period, plasma glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT) and gill Na⁺/K⁺-ATPase activity were significantly altered at all concentrations of both the CA- and DCF-treated fish. In long-term exposure (35 days), gill Na⁺/K⁺-ATPase activity was found to be significantly increased at all concentration of CA and DCF exposures throughout the study period (except at the end of 7th day in 10 and 100 µg L⁻¹) . However, a biphasic trend was observed in plasma GOT and GPT activity when compared to the control groups. In both short- and long-term exposure, a significant (P < 0.01 and P < 0.05) changes were observed in all enzymological parameters of fish C. mrigala exposed to different concentrations of CA and DCF. The alterations of these enzymological parameters can be effectively used as potential biomarkers in monitoring of pharmaceutical toxicity in aquatic environment and organisms.

Biomarker responses and morphological effects in juvenile tilapia Oreochromis mossambicus following sequential exposure to the organophosphate azinphos-methyl

Pesticides are contaminants of aquatic environments. Such ecosystems in the Western Cape, South Africa are at risk as most organophosphates are highly toxic to fish and other aquatic organisms. The objective of this experimental study was firstly to determine the acute toxicity of azinphos-methyl (AZP) to juvenile fish (Oreochromis mossambicus) and, secondly, to investigate the effects of repeated exposure of fish to an array of sublethal concentrations on morphological parameters such as growth, condition factor and organ-somatic indices. Food consumption and feeding response time were investigated as ecologically relevant behavioral endpoints which could affect growth, reproduction and survival and subsequently causes impacts at the population and/or community level. Finally, acetylcholinesterase (AChE) was used as biomarker to investigate effects at sub-organismal level following sequential exposure to AZP. The aim was to determine how sequential spraying procedures, using different exposure concentrations and intervals, affected fish as reflected by their responses at different organizational levels. A dose-dependent effect on feeding impairment was observed in the feeding response experiment. The correlation found between growth impairment, feeding activity and AChE inhibition therefore indicates that frequency of exposure can play an important role regarding the severity of impacts to non-target organisms. This study provides evidence that AZP has harmful effects on non-target aquatic organisms, such as fish which can be manifested in the early developmental stages. Sequential exposures showed that dosage and frequency of spraying and spraying interval could exacerbate harmful effects. AChE inhibition and organosomatic indices can be used effectively to measure effects.

Differential hepatic metal and metallothionein levels in three Feral fish species along a metal pollution gradient

The accumulation of cadmium, copper and zinc and the induction of metallothioneins (MT) in liver of three freshwater fish species was studied. Gudgeon (Gobio gobio), roach (Rutilus rutilus) and perch (Perca fluviatilis) were captured at 6 sampling sites along a cadmium and zinc gradient and one reference site in a tributary of the Scheldt River in Flanders (Belgium). At each site up to 10 individuals per species were collected and analyzed on their general condition factor (K), hepatosomatic index (HSI) and gonadosomatic index (GSI). From each individual fish the liver was dissected and analyzed on Cd, Cu and Zn and MT-content. Although not all species were present at each site, hepatic Cd and Zn levels generally followed the pollution gradient and highest levels were measured in perch, followed by roach and gudgeon. Nevertheless also an effect of site was observed on this order. MT-levels appeared to be the highest in gudgeon although differences with the other species were not very pronounced and depended on the site. Significant relationships were found between hepatic zinc accumulation and MT levels. For each species the ratio MT(theoretical)/ MT(measured) was calculated, which gives an indication of the relative capacity to induce MTs and thus immobilize the metals. Perch had the lowest capacity in inducing MTs (highest ratio). Relationships between hepatic metal levels and fish condition indices were absent or very weak.

Effects of Ibuprofen on hematological, biochemical and enzymological parameters of blood in an Indian major carp, Cirrhinus mrigala

In the present investigation, the most commonly used pharmaceutical drug Ibuprofen (IB) was exposed to an Indian major carp Cirrhinus mrigala under static bioassay method to estimate its toxicological effects for a period of 35 days. The median lethal concentration (LC 50) of IB to the fish C. mrigala for 24h was found to be 142 ppm. In sublethal treatment (1/10th of LC 50 24h value, 14.2 ppm), a significant decrease in erythrocyte (RBC), mean cellular hemoglobin concentration (MCHC) and plasma protein levels were observed throughout the study period when compare to that of their respective controls. In contrast, haemoglobin (Hb), hematocrit (Hct), mean cellular volume (MCV), mean cellular hemoglobin (MCH), leucocyte (WBC), plasma glucose and alanine transaminase (ALT) levels were increased in this study period. On the other hand, a mixed trend was noticed in aspartate aminotransaminase (AST) enzyme activity. Alterations of these parameters can be effectively used as potential biomarkers in monitoring of IB toxicity in the aquatic organisms. However, more detailed studies on these specific biomarkers are needed to assess the impacts of human pharmaceutical drugs in the field of pharmacotoxicology and aquatic toxicology.

Water quality evaluation of two interconnected dam lakes with field-captured and laboratory-acclimated fish, Cyprinus carpio

Karakaya and Sultansuyu Dam Lakes, located in the eastern part of Turkey, are important water sources, both for irrigation and fishery. The main goal of the study was to investigate water qualities of dam lakes using a set of biomarkers in the fish Cyprinus carpio. For this aim, field sample and laboratory-acclimated fish were compared to identify changes in selected biomarkers. The activities of ethoxyresorufin-O-deethylase, glutathione S-transferase, glutathione reductase, and carboxylesterase were determined in liver samples. Also, plasma and liver lactate dehydrogenase, aspartate aminotransferase, and alanine aminotransferase activities were assayed. Brain acetylcholinesterase and carboxylesterase activities were also determined. The hepatosomatic index and condition factors were calculated. Plasma vitellogenin assays were evaluated for the presence of xenoestrogen. Physicochemical values of water samples showed the existence of eutrophication risk, and also, some chemicals in both lakes were determined to be over tolerable limits. The comparisons of samples from both dam lake and laboratory-acclimated fish showed that the lakes may be at risk of pollution by some xenobiotics, namely xenoestrogens and acetylcholinesterase-inhibiting agents.

Assessment of seasonal and sex-related variability of biomarkers in carp (Cyprinus carpio L.) from Karakaya Dam Lake, Turkey

This study examines seasonal changes in the activities of selected biomarkers in carp (Cyprinus carpio L.) from Karakaya Dam Lake and evaluates the influence of gender and environmental factors on those activities. Physicochemical characteristics of water were evaluated in the lakewater. Fish were sampled on seasonal basis, and liver ethoxyresorufin-O-deethylase (EROD), glutathione-S-transferase, glutathione reductase, plasma lactate dehydrogenase, aspartate and alanine aminotransferase, and brain acetylcholinesterase (AChE) activities were assayed. Plasma vitellogenin level and hepatosomatic index and condition factors were also determined. Strong seasonal variations were observed but there were no gender differences among selected markers. The highest vitellogenin level of male fish was detected as 606ng/mL which represents the estrogenicity of water in the lake in September 2005. In addition, the seasonal changes of some biomarkers such as EROD and AChE showed that the lake may be at risk of pollution by some xenobiotics arising from agricultural and/or industrial activities.

Hematological, biochemical and ionoregulatory responses of Indian major carp Catla catla during chronic sublethal exposure to inorganic arsenic

In the present study the acute toxicity of arsenic trioxide in fingerlings of Catla catla an Indian major carp was evaluated with renewal bioassay method. The median lethal concentration of arsenic trioxide to the fish C. catla for 96 h was found to be 20.41 ppm (with 95% confidence limits). From this a non-lethal dose of (2.041 ppm; 1/10th of LC 50 96 value) was selected and fingerlings were exposed to 35 d and hematological, biochemical and ionoregulatory responses were studied at days 7, 14, 21, 28 and 35. Arsenic trioxide produced a significant increase in hemoglobin, hematocrit, WBC count, plasma GPT levels and reduction in RBC count, plasma sodium, chloride, potassium, glucose, protein, GOT, LDH levels as compared to the control group. Gill Na(+)/K(+)-ATPase activity was influenced by arsenic trioxide exposure. A biphasic response was noted in the value of MCH and MCV. However the MCHC level was not altered in arsenic trioxide treated fish throughout the study period. Results of the present investigation suggest that arsenic trioxide affects the hematological, biochemical and ionoregulatory parameters of fish and alterations of these parameters can be useful in environmental biomonitoring of arsenic contamination.

Response of antioxidant system of freshwater fish Oreochromis niloticus to acute and chronic metal (Cd, Cu, Cr, Zn, Fe) exposures

Antioxidant systems are known to be sensitive to metal exposures and are suggested to use in predicting sublethal metal toxicity. In this study, several antioxidant enzymes, such as catalase (CAT), superoxide dismutase (SOD), glutathione S-transferase (GST), glutathione peroxidase (GPX) and glutathione reductase (GR) were measured in the liver and kidney of Oreochromis niloticus exposed to sublethal concentrations of metals (Cd, Cu, Cr, Zn and Fe), using an acute (20 μM, 48 h) or subchronic (10 μM, 20 d) protocol. Beside the several increases of antioxidant enzyme activities, general inhibition was recorded after acute and chronic metal exposures. Results indicated that there were variations in responses of the enzymes to metal exposures, depending upon tissues, metals and exposure types. This study emphasized that the antioxidant enzymes are very sensitive to metals as their activities altered significantly, suggesting they could be helpful in predicting sublethal metal toxicity and useful as an early warning tool in natural monitoring studies.

Mullet and gudgeon liver histopathology and macroinvertebrate indexes and metrics upstream and downstream from a wastewater treatment plant (Febros River--Portugal)

The increased pollution in ecosystems reinforces the importance of both chemical monitoring and biological monitoring of streams and rivers, as an effective water quality-based approach to assess aquatic ecosystem health. In this study, gudgeon (Gobio gobio) and mullet (Mugil cephalus) liver histopathology (biomarker) and some macroinvertebrate community indexes and metrics (bioindicator) were used to evaluate the effect of the wastewater treatment plant (WWTP) of Febros (Avintes) in Febros River water quality and ecosystem health. Regarding macroinvertebrate communities, the Belgian Biotic Index (BBI) and Iberian Biological Monitoring Working Party (IBMWP) indexes suggested that Febros water was slightly polluted, even though the worst situation was found downstream the WWTP discharge. Concerning community metrics, upstream percent of individuals in five numerically dominant taxa (80%) was slightly more superior than the downstream (78%). The presence of intolerant or sensible individuals, determined by percent of Ephemeroptera, Plecoptera, and Trichoptera individuals and number of Ephemeroptera, Plecoptera, and Trichoptera families metrics, was higher upstream WWTP, reflecting a better water quality. The histopathology shows the presence of hepatic lesions in gudgeon and mullet. The statistical analysis of the lesion gradation showed that only necrosis was significantly higher in gudgeon captured downstream the WWTP, while differences were not observed for mullet. The multivariate analysis of data confirmed the existence of differences in hepatic lesions between gudgeon and mullet and between sampling sites. Regarding macroinvertebrate community, this analysis showed that the organic contamination reflected by the BBI and IBMWP indexes values was a determinant factor in the spatial distribution of macroinvertebrates. This work showed that the study of different biological organization levels can be used for a better assessment of ecosystem ecological integrity and can be used as a tool to reveal anthropogenic activity effects in macroinvertebrate diversity and in fish liver pathology from Febros River.

In vitro cyclooxygenase inhibition assay for evaluating ecotoxicity of the surface water and domestic wastewater in the Tone Canal, Japan

Cyclooxygenase (COX) plays an important role in eicosanoid metabolism. Nonsteroidal anti-inflammatory drugs (NSAIDs) function as COX inhibitors and are frequently detected in the aquatic environment. Here, we measured the in vitro COX-inhibiting activity of the surface water and domestic wastewater in the Tone Canal, Japan. The concentrations of several NSAIDs in the some samples were also determined using gas chromatography-tandem mass spectrometry for confirming the validity of the assay. The target compounds were extracted from the samples using a solid-phase extraction cartridge. A dose-response relationship between the inhibiting activity and sample volume were observed in the wastewater sample. The higher COX-inhibiting activities were observed in the wastewater sample, as compared with the samples of the surface water in the canal. These inhibiting activities reflected the trends of NSAIDs distribution in the canal. However, the inhibiting activities of the water samples could not be entirely explained by the NSAIDs that were selected for instrumental analysis in this study. Other compounds that were not measured by instrumental analysis in this study might contribute to the inhibiting activities. Therefore, the COX-inhibiting assay would be effective for evaluating inclusive ecotoxicity in the aquatic environment.

Cytosolic distribution of Cd, Cu and Zn, and metallothionein levels in relation to physiological changes in gibel carp (Carassius auratus gibelio) from metal-impacted habitats

In the present study the impact of environmental metal contamination in gibel carp (Carassius auratus gibelio) was investigated coupling disturbances in subcellular metal distribution to effect biomarkers. Gibel carp were caught at six different sampling sites in Flanders (Belgium), characterized by different degrees in environmental metal contamination. Tissue Cd, Cu and Zn concentrations and total metallothioneon (MT) levels were determined in gills, liver and kidney. Cytosolic metal distribution was measured in the main accumulating organs, liver and kidney, revealing tissue- and metal-dependent profiles. The MT pool dominated the cytosolic distribution profile. Although the importance of the MT pool increased with increasing environmental and cytosolic metal concentrations, also an undefined fraction of Cu and Cd fractions (probably free metal ions or metals bound to small organic complexes) increased at the most contaminated sampling sites. Disturbances in serum ion concentrations, serum alanine aminotransferase activity (ALT), hematocrite and condition factor were measured, as indicators of toxic effects. At the sampling site with the highest environmental Cd pollution a significant decrease in serum Ca(2+) concentrations and a significantly increased serum ALT activity were measured suggesting incomplete detoxification of Cd. Increased serum ALT concentrations suggested structural liver damage. The fact that the liver tissue, and probably also the kidney, could not cope with this high Cd burden in combination with the increased uptake of dissolved Cd through the gills most probably contributed to the perturbed serum Ca(2+) homeostasis.

The comparison of heavy metal accumulation ratios of some fish species in Enne Dame Lake (Kütahya/Turkey)

The metal accumulation levels for muscle, skin, gill, liver and intestine tissues of some Cyprinidae species (Carassius carassius, Condrostoma nasus, Leuciscus cephalus and Alburnus alburnus) in Enne Dame Lake (Kütahya/Turkey), which is mostly fed by hot spring waters, were investigated. Analyses were performed for copper (Cu), zinc (Zn), manganese (Mn), iron (Fe), cobalt (Co), magnesium (Mg), nickel (Ni), chrome (Cr) and boron (B) using inductively coupled plasma-optic emission spectroscopy (ICP-OES), and cadmium (Cd) using atomic absorption spectrophotometer (AAS) utilizing microwave digestion techniques. The concentrations of the heavy metals found in the fish varied in the follow ing ranges: Cu: < DL-7.04, Zn: 6.96-357.25, Mn: < DL-20.70, Ni: < DL-6.21, Fe: 9.62-2500.33, Cr: < DL-1.74, Co: < DL-0.54, Cd: 0.01-0.27 and Mg: 197.44-904.90 mg/kg wet weight. While B had the second highest concentration in the water of the lake, it was not encountered in any tissue of the investigated species. In all tissues and the species, While the bioaccumulation factors (BAFs) of Mn, Zn, Fe and Cu were remarkably high, the BAFs of Mg, Cr, Co, and B were also fairly low or none. Although the heavy metal accumulation levels for the muscle were generally lower than other tissues, there were some exceptions. Cd level in the muscle of C. carassius was higher than the permissible limit stated by Turkish legislation, FAO and WHO. The mean metal amounts for all the investigated tissues and species are statistically compared and discussed in this study.

Bioaccumulation of micropollutants and biomarker responses in caged carp (Cyprinus carpio)

At four different aquatic sites in Flanders (Belgium) with different types and degrees of contamination, juvenile carp (Cyprinus carpio) were exposed in cages for 4 weeks. After exposure, metals, polychlorinated biphenyls (PCBs), and selected organochlorine pesticides (OCPs) were analyzed in the tissues of the carp. Besides pollutant accumulation, several effects were measured as well. Condition measures such as changes in weight, condition factor (CF), and hepatosomatic index (HSI) were assessed. In addition, activity of acetylcholinesterase (AChE) and a set of blood biochemical parameters were measured. At all sites, accumulation of metals in the fish tissues was observed. Levels of cadmium and lead at some of the exposure sites were higher than the levels at the start and comparable to levels in fish from moderately metal-contaminated sites. For most organic pollutants, however, levels were not significantly higher than at the start. Only for two PCB congeners, levels had slightly increased but were still lower than levels in carp captured at noncontaminated sites. Although food limitation probably caused some of the observed effects, significant relationships were found between metal load in tissues and CF, AChE, plasma osmolality and HSI. This study shows that caged carp might be useful for the assessment of bioaccumulation and some effects of micropollutants in aquatic ecosystems.

Monitoring pollution in Esmoriz-Paramos lagoon, Portugal: liver histological and biochemical effects in Liza saliens

The Esmoriz-Paramos lagoon is one important ecosystem located in the Northwest coast of Portugal. This study is concerned with the assessment of pollution of the lagoon contributed by urban, industrial and agricultural activities. The parameters selected for this aim were the occurrence of hepatic histological alterations and plasma blood biochemistry in Liza saliens, the dominant fish in this lagoon. Blood parameters were compared between mullets collected from the lagoon and from the sea and included plasma enzyme activities (aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP)), glucose (GLU) and total protein (TP). A positive relationship between hepatocyte vacuolization index and hepatosomatic index was found, suggesting that lipid accumulation could have contributed to the increase of liver weight. The hepatic alterations recorded included general diagnostic categories and additionally large areas of heterogeneous parenchyma, composed of hepatocytes with different spectrum of vacuolization. Liver histopathological evaluation revealed a sample prevalence of 34% for heterogeneous parenchyma, 31% for foci of necrosis and 9% for non-neoplastic lesions. No neoplastic lesions were found. Livers with heterogeneous parenchyma showed higher Cu and Zn content than livers without this category of lesion, suggesting that metals accumulated could trigger this hepatic alteration. AST was higher in mullets from the lagoon than in mullets from the sea, but no differences in ALP and ALT were found, suggesting a change in protein metabolism as an adaptive response to metals exposure. The higher glucose and protein contents observed in fish caught in the lagoon are consistent with a stress response and the measurement of plasma AST activity could be a sensitive indicator of lagoon fish stress. In conclusion, Esmoriz-Paramos lagoon biomonitorization, using indicator species will proceed to assess the impact of the restoration program under development by the Portuguese government.

Ecotoxicological assessment of water pollution in Sariyar Dam Lake, Turkey

Given the effects of environmental pollution and different biotic factors on some important biochemical markers, as enzymes, two fish species inhabiting the Sariyar Dam Lake, Turkey have been investigated. Ethoxyresorufin O-deethylase, glutathion S-transferase, lactate dehydrogenase, alkaline phosphatase, acid phosphatase, and alanine and aspartate amino transferase activities have been measured in liver samples of Cyprinus carpio and Capoeta tinca. Also, brain acetylcholinesterase and carboxylesterase activities have been measured for the same samples. Selected enzymes confirmed that Sariyar basin is polluted by urban wastes and agricultural and industrial activities for many years. Organochlorine (OC) pesticide residues, caused by intensive agricultural activities, have also been observed in water, sediment samples, and adipose tissues of carp. Monitored results showed that SDL was polluted by different kinds of OC compounds such as DDT and its derivatives which are accumulated in adipose tissues of carp. Highest accumulation was found for beta-BHC in carp. The changes of enzyme activities in this study may be related to environmental pollution, while enzyme activity variations could be attributed to variable pollutants and variable concentrations of these pollutants. The results highlighted the potential convenience of these biomarkers to be used as components of environmental monitoring program in risk assessment studies in SDL. Since a seasonal variation in selected enzyme activities was found, the possible implications of such variability in the use of these enzymes as environmental biomarkers are also discussed. Hepatic cytosolic EROD did not show any significance according to the pollution factors in the lake which may be attributed to relatively less contamination by organic compounds such as PAH products.

Monitoring of cholinesterase-inhibiting activity in water from the Tone canal, Japan, as a biomarker of ecotoxicity

The cholinesterase (ChE)-inhibiting activity of water and the concentrations of representative inhibitors were monitored in the Tone canal, Japan, during April to December 2006. The ChE-inhibiting activity, measured by using horse serum as enzyme source, increased from late April to early June, and from September to October. Although the trends in the ChE-inhibiting activity of the samples were consistent with concentration changes of organophosphorus pesticides, ChE-inhibiting activity was not observed in samples replicated on the basis of the chemical concentrations detected. The water samples were treated with chlorine to enhance the ChE-inhibiting activity by conversion of thiophosphate pesticides to phosphate pesticides. The ChE-inhibiting activity increased in almost all the chlorine-treated samples, although organophosphorus pesticides were either not detected or detected in traces in the samples by gas chromatographic-mass spectrometric analysis. These results suggested that assay of ChE-inhibiting activity is important for evaluating the ecotoxicity of environmental water, because toxicological investigations based solely on inhibitor concentrations may underestimate the contamination. Furthermore, the combined method of oxidation by chlorination and the ChE assay is very effective for screening and monitoring of organophosphorus pesticides in environmental water.

Histopathological changes in the livers and kidneys of fish in Sariyar Reservoir, Turkey

In this study, a total of 180 fish specimens (wels: Silurus glanis-60; common carp: Cyprinus carpio-60; bleak: Alburnus escherichii-60) of ages between one and two were caught at three different stations in Sariyar Reservoir. The histological changes in the livers and kidneys of three different species of fish were detected microscopically and evaluated with quantitative analyses. Also, organochlorine pesticide residues (OCP) have also been determined in the water and sediment samples and in the adipose tissues of fish caught in these stations. Results show that the reservoir was polluted by different kinds of OCP compounds and these chemicals have accumulated in the fish tissues. As a result of these analyses, histopathological changes were observed in the livers and kidneys of fish specimens, such as mononuclear cell infiltration, congestion and nuclear picnosis. Also intra-cytoplasmic cholestasis in their livers and tubular degenerations in the kidneys were observed. The incidences of the histopathological changes in wels and carps were found to be higher than bleak. Furthermore, histopathological changes in fish samples caught from Usakbuku were much more than the samples caught from other stations (Sariyar and Nallihan Bird Paradise Stations). In this study the possible reasons of histopathological changes were evaluated with respect to different fish species and localities and also the findings were evaluated in relation to OCP contamination.