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Two fish species from the middle reaches of the Yangtze River, China, were sampled to investigate the occurrence, tissue distribution, age-dependent accumulation and ecological risk assessment of 24 organophosphorus flame retardants (OPFRs). Seventeen OPFRs were detected in tissue samples with a total concentration ranging from not detected (ND) to 1092 ng g−1 dw. Cl-OPFRs were predominant in all tissues (mean: 145 ng g−1 dw, median: 72.9 ng g−1 dw) and the concentrations of OPFRs in brain were the greatest (crucian carp: 525 ng g−1 dw, silver carp: 56.0 ng g−1 dw) compared with the other three organs (e.g., liver, muscle and gonad). Furthermore, the total concentrations of OPFRs in crucian carp tissues were significantly greater than those in silver carp (P < 0.01). Age-dependent accumulation of OPFRs was observed in the two fish species, but the accumulation profiles in the two fish species were different. Ecological risk assessment demonstrated that both fish species were at medium to high risk, and TDCIPP was a main contributor (>50%). [Display omitted] • OPFRs were widely detected in fish from the Yangtze River. • Brain was a main accumulation organ of OPFRs. • OPFRs caused age-dependent bioaccumulations in wild fish. [ABSTRACT FROM AUTHOR]

It has been reported that antibiotic enrofloxacin can impair reproductive function of mammals, induces multi-generational oscillatory effects on reproduction of Caenorhabditis elegans , and disturbes endocrine system in grass carp. This study aims to explore the effect of short-term enrofloxacin exposure on sex steroid hormones biosynthesis in Carassius auratus var. Pengze through assessing the contents of growth hormone (GH), thyroid hormone 4 (T 4), estradiol (E 2) and testosterone (T) in plasma, and investigating sex steroid hormones biosynthesis based on targeted metabonomics analysis, and determining expression level of some important genes, gonadotropin-releasing hormone (gnrh), gonadotropin hormone 1-β (gth1-β), gonadotropin hormone 2-β (gth2-β) and cyp19a1a in hypothalamus-pituitary-ovary axis (HPOA). We found that short-term exposure of enrofloxacin disordered contents of E 2 and T in plasma of fish determined by ELISA detection, T content elevation and E 2 content decline, which was confirmed by the following data from targeted metabonomics analysis of plasma. The metabonomic results showed that both T and its upstream intermediate products during the process of sex steroid hormones biosynthesis in fish were increased significantly, but E 2 content was decreased markedly. At the exposure 24 h of enrofloxacin, expression of gnrh in hypothalamus, gth1-β and gth2-β in pituitary were promoted. Meanwhile GH and T 4 contents in plasma, two inducers of sex steroid hormones synthesis, were augmented, which indicated that sex steroid hormones biosynthesis was improved. However cyp19a1a expression in ovary was repressed, and content of estriol (E 3) was upregulated. These data suggested that enrofloxacin promoted sex steroid hormones biosynthesis and conversion of E 2 to estriol (E 3), but inhibited the conversion of T to E 2. Finally, content of E 2 was declined sharply. Animal specific antibacterial enrofloxacin is widely detectable in aquatic ecosystem, exposure of the agent can induce adverse effects on plants and animals. This study firstly evidenced induction of disruption of sex steroid hormones by enrofloxacin in fish, which indicates enrofloxacin is an endocrine disruption compound that can induce endocrine disruption of animals, including fish. [Display omitted] • Short-term enrofloxacin exposure promotes secretion of GH and T 4 in crucian carp. • Enrofloxacin inhibits biotransformation of T to E 2 , inducing accumulation of T. • Enrofloxacin promotes E 2 metabolism to E 3 , resulting in reduction of E 2. • Enrofloxacin promotes expression of gnrh and gth genes. [ABSTRACT FROM AUTHOR]

Organophosphate flame retardants (OPFRs) can rapidly biotransform into two types of metabolites in biota: (1) organophosphate diesters (DAPs) and (2) hydroxylated OPFRs (HO-OPFRs). Therefore, the levels of parent OPFRs alone are not sufficient to indicate OPFR pollution in biological organisms. This study analyzed 12 OPFR metabolites, including 6 DAPs and 6 HO-OPFRs, in a typical freshwater food chain consisted of crucian carp, catfish, mud carp, snakehead, and oriental river prawn. The total concentrations of OPFR metabolites were comparable to those of parent OPFRs, and ranged from 0.65 to 17 ng/g ww. Bis(2-butoxyethyl) 3′-hydroxy-2-butoxyethyl phosphate (14%–77%), di- n -butyl phosphate (DNBP) (6.7%–24%), bis(1-chloro-2-propyl) phosphate (BCIPP) (0.7%–35%), and 1-hydroxy-2-propyl bis(1-chloro-2-propyl) phosphate (BCIPHIPP) (6.0%–24%) were the major OPFR metabolites. Various aquatic species exhibited significant differences in their OPFR metabolite/parent ratios (MPR) (p < 0.05), indicating varying biotransformation potentials of different organisms for various OPFRs. The growth-independent accumulation of tri- n -butyl phosphate (TNBP), tris(chloro-2-propyl) phosphate (TCIPP), triphenyl phosphate, and 2-ethylhexyl diphenyl phosphate in mud carps could be explained by their biotransformation potential. A significant negative correlation was found between the concentration of bis(2-butoxyethyl) phosphate and δ15N values (p < 0.05), with a calculated trophic magnification factor (TMF) of 0.66. Significant positive correlations were observed between BCIPP and TCIPP (R2 = 0.25, p < 0.05), as well as between DNBP and TNBP (R2 = 0.30, p < 0.01), implying that these two DAPs could be used as biomarkers to quantitatively assess TCIPP and TNBP contamination in wild aquatic organisms. [Display omitted] • DAPs and HO-OPFRs had high detection frequencies and comparable levels to parent OPFRs. • Biotransformation affected the species- and growth-dependent accumulation of OPFRs. • BBOEP underwent trophic dilution in the aquatic food chain. • DAPs and HO-OPFRs can be used as biomarkers for OPFR monitoring. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the toxic effects of polyethylene microplastics (PE-MPs) by measuring the bioaccumulation, hematological parameters, and antioxidant responses in crucian carp (Carassius Carassius) exposed to waterborne 22–71 μm PE-MPs. C. carassius (mean weight, 24.0 ± 2.1 g; mean length, 13.1 ± 1.2 cm) were exposed to PE-MPs at concentration of 0, 4, 8, 16, 32, and 64 mg/L for 2 weeks. The accumulation of PE-MPs in each tissue of C. carassius was significantly increased in proportion to the PE-MPs concentration; the highest accumulation was observed in the intestine, followed by the gills and liver. Hematological parameters, plasma components and antioxidants responses were significantly affected by PE-MPs in a concentration-dependent manner. Exposure to ≥32 mg/L PE-MPs induced a significant decrease in red blood cells (RBCs), hemoglobin (Hb) content, and hematocrit values. However, exposure to ≥32 mg/L PE-MPs induced oxidative stress in the liver, gill, and intestine of C. carassius , thereby resulting in a significant increase in the levels of superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST) and a decrease in glutathione (GSH) levels. The effects of interaction between the PE-MPs and exposure periods showed no significant changes in bioaccumulation, hematological parameters, plasma components and antioxidant responses. These finding indicate that the exposure to ≥32 mg/L PE-MPs could cause a significant accumulation in specific tissues of C. carassius , resulting in changes in hematological parameters, plasma components, and antioxidant responses. However, the interaction between PE-MPs and exposure periods had no significant effects, thereby suggesting the lack of toxicological interactions between PE-MPs and exposure periods in C. carassius. [Display omitted] • Accumulation pattern of PE-MPs in C. carassius followed the order intestine > gill > liver. • Hematological parameters and plasma components of C. carassius were significantly altered. • PE-MP exposure above 32 mg/L induced significant changes in antioxidant responses of C. carassius. • PE-MP exposure causes blood toxicity and oxidative stress. • Interactive effects between PE-MPs and exposure periods had no significant effects. [ABSTRACT FROM AUTHOR]

Psychoactive substances are becoming new concern in environmental research with their increasing applications and the potential threats to fishery production as these substances could alter the behavior of fish and consequently affect the yield and quality of cultured fish. In this study, the accumulation and risk of twenty psychoactive substances were investigated in five species of cultured fish in Eastern China. The results showed that the total concentrations of these twenty psychoactive substances ranged from 0.15 to 0.92 ng mL−1 in the plasma among the five species of cultured fish with an order of perch > crucian carp > bighead carp > grass carp > silver carp. Diazepam (DIAZ) and methamphetamine (MAMP) were identified as the most frequently detected compounds, which were found in 100% and 93% of the samples with a median concentration of 0.15 and 0.12 ng mL−1 in the plasma, respectively. Although all of the psychoactive substances posed low or negligible risk, species-specific analysis of risk prioritization revealed that alprazolam, MAMP, temazepam and DIAZ exhibited the greatest potentials of hazard to all species of the cultured fish but with a species-dependent variation. These findings suggest that the adverse effects of psychoactive substances on fishery production, especially on different species, should be considered. [Display omitted] • Psychoactive substances were detected in different species of cultured fish. • The plasma total levels of psychoactive substances ranged from 0.15 to 0.92 ng mL−1. • Diazepam and methamphetamine are the most frequently detected substances. • The psychoactive substances generally posed low or negligible risk in the fish. • ALPZ, MAMP, TEMZ and DIAZ pose higher hazard potential among the substances. [ABSTRACT FROM AUTHOR]

Di-(2-ethylhexyl) phthalate (DEHP) is one of the most extensively utilized plasticizers in the plastic manufacturing process. It is widely used in various fields due to its low cost and excellent effect. Although there is evidence that DEHP is harmful to animal and human health, DEHP-induced gill toxicity in aquatic organisms is inconclusive, and its mechanism has not been fully elucidated. Here, we investigated the effects of DEHP acute exposure on crucian carp gills at environmentally relevant concentrations of 20, 100, and 500 μg/L. Multi-omics profiling and biochemical assays were employed to characterize the potential toxicological mechanisms. The results showed that acute exposure to 100 and 500 μg/L of DEHP leads to oxidative stress in gills, as evidenced by overproduction of reactive oxygen species (ROS), increased antioxidant enzyme activity, and the transformation of glutathione from reduced to oxidized form, resulting in lipid peroxidation. Integrative analysis of transcriptomics and metabolomics indicated that increased purine metabolism was the potential source of increased ROS. Moreover, lipid metabolism disorder, including arachidonic acid metabolism, induces inflammation. Further, DEHP causes the imbalance of the CYP enzyme system in the gill, and DEHP-induced gill toxicity in crucian carp was associated with interference with CYP450 homeostasis. Taken together, this study broadens the molecular understanding of the DEHP-induced gill toxicity in aquatic organisms and provides novel perspectives for assessing the effects of DEHP on target and non-target aquatic organisms in the environment. [Display omitted] • DEHP activates protective responses in the antioxidant system of the gill. • ROS overproduction is related to the increase of purine metabolism. • Dysregulation of lipid metabolism contributes to increased pro-inflammatory effects. • DEHP-induced gill toxicity is associated with disrupting the CYP450 homeostasis. [ABSTRACT FROM AUTHOR]

The tissue distribution, bioconcentration, metabolism and biological effects of the antifungal medication ketoconazole were investigated in fish, crucian carp ( Carassius auratus ) were exposed to a series of nominal concentrations (0.2, 2 and 20 μg/L) for 14 days. The ultra-high performance liquid chromatography tandem triple quadrupole mass spectroscopy (UPLC/MS/MS) analysis was used to determine the bioconcentration of ketoconazole and its metabolites in fish. The highest tissue concentration of ketoconazole was observed in the liver with the bioconcentration factor of 257.2, which is lower than the estimated BCF value. The ability of crucian carp to metabolize ketoconazole was confirmed and the results pointed out the existence of seven metabolites likely formed via oxidation of imidazole ring and the metabolic alteration of the piperazine rings. In addition, acetylcholinesterase, 7-ethoxyresorufin O-deethylase, superoxide dismutase and glutathione S -transferase changed significantly after 3, 7 and 14 days of exposure ( P < 0.05), which indicated that the accumulation and metabolism of ketoconazole in fish tissues may account for the biological effects. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the interactive effects of fluoxetine (FLU), roxithromycin (ROX) and propranolol (PRP) on the bioaccumulation and biochemical responses in the crucian carp Carassius auratus . After 7 days of binary exposure (ROX + FLU and PRP + FLU), the addition of waterborne FLU at nominal concentrations of 4, 20 and 100 μg L −1 significantly increased the accumulation of ROX and PRP in fish livers in most cases, although elevated ROX and PRP bioaccumulation levels were not observed in muscles or gills. The inductive response of 7-ethoxyresorufin O -deethylase (EROD) to PRP and that of 7-benzyloxy-4-trifluoromethyl-coumarin O -dibenzyloxylase (BFCOD) to ROX were inhibited by the co-administration of FLU at all tested concentrations. Correspondingly, marked inhibition of CYP1A and CYP3A mRNA expression levels was observed in the livers of fish co-treated with FLU + PRP and FLU + ROX relative to their PRP- and ROX-only counterparts, respectively. In addition, as reflected by superoxide dismutase (SOD) activity and malondialdehyde (MDA) content, co-exposure to ROX + FLU and PRP + FLU seemed to induce stronger antioxidant responses than single pharmaceutical exposure in fish livers. This work indicated that the interactive effects of pharmaceutical mixtures could lead to perturbations in the bioaccumulation and biochemical responses in fish. [ABSTRACT FROM AUTHOR]

This study investigated the concentrations of phenolic endocrine-disrupting chemicals (EDCs) and the incidence of ovo-testis (intersex) in wild crucian carp ( Carassius carassius ) sampled from the Hun River. As expected, nonylphenols (NP) and bisphenol A (BPA) were detected in all samples, and octylphenols (OP) were found in most samples. NP concentrations ranged from 1290 ± 584 to 3111 ± 2071 ng g −1 wet weight (ww) in July and from 1132 ± 644 to 1556 ± 587 ng g −1 ww in November; OP ranged from 6 ± 7 to 46 ± 38 ng g −1 ww in July and from no detection to 22 ± 16 ng g −1 ww in November; and BPA ranged from 4 ± 9 to 41 ± 24 ng g −1 ww in July and from 6 ± 5 to 59 ± 24 ng g −1 ww in November. Moreover, the concentrations of these compounds were higher in fish found down-stream of the sewage treatment plant (STP), and the lowest concentrations were found in fish up-stream of the STP. Concentrations of these EDCs in muscles might be correlated with the prevalence of intersex traits in wild fish, suggesting that these compounds contribute, at least in part, to the occurrence of intersex morphology. Thus, phenolic EDCs discharged from the STP pose a risk to the aquatic ecosystem in the Hun River. [ABSTRACT FROM AUTHOR]

Over the past few decades, endosulfan, one of the polychlorinated pesticides still in use, has received considerable attention of a number of international regulations and restriction action plans worldwide. This study aimed to evaluate the cytogenetic effects of endosulfan using robust genotoxicity assays, along with the oxidative stress pathways in order to understand biochemical mechanism, in Carassius carassius L. The LC 50–96 h (95% confidence limits) value of endosulfan was 0.070 (0.046–0.093) ppm; and on its basis three test concentrations (sub-lethal I: 0.052, II: 0.035 and III: 0.017 ppm) were selected for 35 d in vivo exposure. The mean concentration of endosulfan in aquaria was always constant, when analyzed by dispersive liquid–liquid micro extraction (DLLME) followed by GC–MS. Autopsy was done on days 1, 2, 3, 4, 7, 14, 21, 28 and 35 of endosulfan exposure; the micronucleus formation (MN), authenticated by scanning electron microscopy, and chromosomal aberrations (CA), were induced significantly ( p < 0.05) in all the treated groups, including positive control cyclophosphamide (4 ppm), when compared to negative control. Similarly lipid peroxidation (LPO) was induced significantly with the maximal at higher concentration (SL-I) on 4th day (722.45%; p < 0.01). Antioxidant biomarkers like glutathione reduced, superoxide dismutase and catalase also fluctuated significantly ( p < 0.01) in all treatment groups. Collective findings demonstrated that genotoxic effects were invariably accompanied and correlated with increased oxidative stress and disturbance of antioxidant enzymes; and the MN and CA assays are useful tools in determining potential genotoxicity of aquatic xenobiotics and might be appropriate as a part of monitoring program. [ABSTRACT FROM AUTHOR]

Highlights: [•] ROX in water could accumulate in crucian carp, particularly in liver and bile. [•] Seventeen metabolites were detected in bile. [•] A plausible scheme for biotransformation pathways of ROX in fish was depicted. [•] ROX could induce change of biomarkers, which related to ROX or its metabolites. [ABSTRACT FROM AUTHOR]

Abstract: Polybrominated diphenyl ethers (PBDEs) are extensively used as a class of flame retardants and have become ubiquitous environmental pollutants. Significant biotransformation of some PBDEs via reductive debromination has been observed. However, little is known about the fate of lower brominated BDEs in fish. In this study, the tissue distribution, excretion, depuration and biotransformation of 4,4′-dibromodiphenyl ether (BDE 15) were investigated in crucian carp (Carassius auratus) which were exposed to spiked water solution at different concentrations for 50d, followed by a 14-d depuration period. Bioaccumulation parameters were calculated and the results showed that BDE 15 was mainly concentrated in the gill and liver. In particular, five biotransformation products of BDE 15 in carp were identified using GC–MS/MS. Besides two debrominated metabolites, three of the metabolites were mono-OH-BDE 15, diOH-BDE 15 and bromophenol. Our results unequivocally suggested that BDE 15 oxidation did occur via the formation of hydroxylated (OH-) metabolites in crucian carp exposed in vivo. These findings will be useful for determination of the metabolic pathways of PBDEs in freshwater fish, especially about their oxidation metabolism. [Copyright &y& Elsevier]

Abstract: Polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) were measured by high resolution gas chromatograph/high resolution mass spectrometer (HRGC/HRMS) in six food groups from Luqiao (LQ) where the e-waste has been recycled and from Yuhang (YH) where the agriculture dominates in Zhejiang Province in China. The total WHO-TEQ values of PCDD/Fs and DL-PCBs in selected foods from LQ were significantly much higher than those from YH. The highest level of the total WHO-TEQ was in crucian carp (10.87pgg−1 w.w.) followed by duck (3.77pgg−1 w.w.), hen eggs (2.80pgg−1 w.w.), chicken (2.43pgg−1 w.w.), rice (0.08pgg−1 w.w.) and vegetables (0.022pgg−1 w.w.) in LQ. By contrast, the highest levels were measured in duck (0.74pgg−1 w.w.) followed by hen eggs (0.69pgg−1 w.w.), crucian carp (0.55pgg−1 w.w.), chicken (0.44pgg−1 w.w.), vegetables (0.002pgg−1 w.w.) and rice (0.0002pgg−1 w.w.) in YH, respectively. The monthly intake of PCDD/Fs and DL-PCBs for the local residents was 401.75pgWHO-TEQg−1 w.w. in LQ, which is above the provisional tolerable monthly intake (PTMI) set by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). We determined a monthly intake of 37.13pgWHO-TEQg−1 w.w. in YH, which is below the PTMI. Crucian carp was the predominant contributor to the estimated monthly intake (EMI), accounting for 67.74% and 36.51% in LQ and YH, respectively. High levels of PCDD/Fs and DL-PCBs in selected foods indicate severe contamination of these pollutants in the e-waste recycling site. [Copyright &y& Elsevier]

Abstract: Seven typical synthetic musks (SMs) in the samples from the surface water, sediment and fish of the Haihe River were measured. The SM concentrations in the sediment and surface water of the Haihe River were significantly lower than those in the Dagu Drainage River and Chentaizi Drainage River (p <0.05). Along the flow direction, the SM concentrations in surface water and sediment tended to increase from the upstream to the downstream of Dagu Drainage River. The Bioaccumulation factors (BAFs) of galaxolide (HHCB) and tonalide (AHTN) were calculated at high levels in the muscles of crucian carp, common carp, and silver carp. Most of the biota-sediment accumulation factors (BSAFs) for HHCB and AHTN were higher than 1.7, suggesting magnification possibly exist in the musk bioaccumulations of the three fishes in the Haihe River. No significant differences in HHCB/AHTN ratios were observed among the water, fish, and sediment samples (p >0.05). However, the HHCB/AHTN values in the Haihe River were much lower than those in the Dagu Drainage River and Chentaizi Drainage River (p <0.05). Compared with several typical persistent organic pollutants (POPs), the musk concentrations were higher or comparable in the Haihe River. [Copyright &y& Elsevier]

Abstract: Hexabromocyclododecanes (HBCDs) are now emerging ubiquitous contaminants due to their wide usage, persistence and toxicities. To investigate the bioaccumulative characteristics of HBCDs, sediments, Winkle (Littorina littorea), crucian carp (Carassius carassius) and loach (Misgurnus anguillicaudatus) were collected from two streams near an E-waste dismantling site in China, and HBCD exposure test was then conducted on Chinese rare minnow. The concentration of HBCDs was 14ngg−1 dry weight in sediments, 186, 377 and 1791ngg−1 lipid weight in winkle, crucian carp and loach, respectively. γ-HBCD was found to be the dominant diastereoisomer in the sediments (63% of total HBCDs). However, α-HBCD was selectively accumulated in the biotic samples and contributed to 77%, 63% and 63% of total HBCDs in winkle, crucian carp and loach, respectively. Moreover, an enrichment of (−)-enantiomers of α- and γ-HBCD were found in the winkle. The reverse results were observed in the crucian carp and loach. Similar observations of diastereoisomeric and enantiomeric composition were obtained in Chinese rare minnow with those found in the crucian carp and loach. These results indicate that the freshwater species from the streams are contaminated by HBCDs. α-HBCD can be selectively accumulated in organisms and the accumulative characteristics are enantioselective among species. [Copyright &y& Elsevier]

Concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were analyzed in freshwater fish (crucian carp) taken from 16 locations in nine rivers and a wetland in Korea, during 2000–2004. Dioxin-like polychlorinated biphenyls (DL-PCBs) were also analyzed in the same samples but over shorter period (2002–2004). Concentrations on a wet weight basis for 3 years (2002–2004) ranged from below the detection limit (DL) to 0.36pg TEQg−1 wet wt. for PCDDs, below the DL to 2.0 for PCDFs, and from 0.02 to 1.9 for DL-PCBs, with a mean of 0.07, 0.33 and 0.83pg TEQg−1 wet wt., respectively. The proportions of PCDDs, PCDFs and DL-PCBs in the total dioxin TEQ for 2002–2004 were 7%, 26% and 67%, respectively. While the temporal trend showed a significant decrease in PCDDs/DFs concentrations over the 5-year study period, DL-PCBs did not show significant change in concentration over the 3-year period. The results suggest that DL-PCBs concentrations should be determined when total dioxin TEQ is analyzed in freshwater fish. [Copyright &y& Elsevier]

The endocrine response of crucian carp injected intraperitoneally with extracted microcystins (MC) was investigated in this study. Fish were injected intraperitoneally either with 0.75% NaCl (control) and Microcystis extract corresponding to 150 and 600μg microcystins per kg body weight. The plasma levels of triiodothyronine (T3), thyroxine (T4), free triiodothyronine (FT3), free thyroxine (FT4), and cortisol were determined at 0, 1, 3, 12, 24, and 48h post-administration of MC-containing extract. Treated fish displayed abnormal behaviors, such as a startle response and disoriented swimming, as well as changes in ventilation rates. Plasma cortisol concentrations of fish in both dose groups significantly increased after administration of extracted MC and remained high throughout the experiment, which suggested that MC elicited a stress response in treated fish. The profiles of cortisol changes in treated fish appeared to be dose dependent, indicating that fish in the high dose group experienced greater MC-induced disturbance. Mortality occurred after 12h in the high dose group. Plasma levels of T4, T3, FT4, and FT3 did not vary significantly between the control fish. In contrast to this, fish exposed to MC-containing extract showed significant declines in T3, FT4, and FT3 levels in a dose-dependent manner throughout the experiment. Plasma T4 levels, however, did not vary significantly in the low dose group, whereas they decreased significantly at 48h post injection in the high dose group. This study demonstrates that administration of microcystins-containing extract causes a stress response and reduces the plasma levels of thyroid hormones in crucian carp. These results illustrate that microcystins exerted potent effects on the endocrine system of crucian carp, through activating their hypothalamus-pituitary- interrenal axis and disturbing thyroid function. [Copyright &y& Elsevier]

Alachlor has been widely used in agriculture all over the world. It is suggested that it may be a carcinogen and also an environmental estrogen. In this paper, the physiological and biochemical perturbations of crucian carp (Carassius auratus) exposed to alachlor at different concentrations over 60 days were investigated. The gonadosomatic index (GSI) and hepatosomatic index (HSI) were measured. The activity of hepatic antioxidant defense and detoxifying enzymes, superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST) and the content of glutathione (GSH) were determined and compared with the control group. The result showed that GSI and HSI decreased significantly (P <0.05) in almost all treatments. The activities of SOD, CAT and GST were induced continuously (P <0.05), while the content of reduced glutathione (GSH) was inhibited on the whole. These changes reflect that the antioxidant systems of the tested fishes were affected. The possible defense mechanistic implications about the changes were thus discussed. Furthermore, hepatic SOD and GST were sensitive to alachlor at low concentration, indicating that they might be potential biomarkers in early detection of alachlor contamination in aquatic ecosystems. [Copyright &y& Elsevier]

Abstract: A direct interaction of lead (Pb) with kidney DNA from silver crucian carp (Carassius auratus gibelio) has been systematically studied in vitro using multi-techniques, including UV–vis absorption, extended X-ray absorption fine structure, vacuum ultraviolet circular dichroism spectral methods and gel electrophoresis. We find that Pb is bound with four oxygen or nitrogen atoms of DNA in its fresh shell at the distances of 2.64Å. Additionally, Pb may bind to the oxygen atom of nucleic acid or nitrogen atom of base pairs of DNA in that obvious changes in the secondary structure of DNA are found after Pb treatment. However, this direct interaction of Pb with DNA do not cause DNA cleavage in vitro. [Copyright &y& Elsevier]

Muscles of two species of fish collected in Qiangtangjiang River were analyzed for polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) by high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS). Average concentrations of total PCDD/Fs in Crucian carp and White Amur bream were 1. 14–7. 88pgg−1 ww and 1. 02–8. 18pgg−1 ww respectively. Corresponding values for PCBs were 469. 36–10972pgg−1 ww and 364. 79–4948. 0pgg−1 ww. Average total WHO-TEQ of Crucian carp and White Amur bream from five areas ranged from 0. 25 to 2. 33pgg−1 ww and 0. 30 to 1. 70pgg−1 ww. The contamination level was compared with other studies and risk assessment was discussed. [Copyright &y& Elsevier]

Abstract: Polychlorinated biphenyls (PCBs) levels in crucian carp were determined at 20 locations along four major river systems, several small-scale rivers and a wetland in Korea. Twenty-eight congeners, ranging from tri- to hepta-CBs were detected. A gas chromatograph with a mass selective detector was used to quantify the individual PCB congeners. The objectives of this study were to investigate the levels of contamination of PCBs in freshwater fish and to observe the pattern of their distribution. The sampling locations were chosen among 31 sampling sites that are currently used as environmental residue checkpoints by the Korean Ministry of Environment. Concentrations of individual congeners ranged from not detectable (n.d.) to 0.75ngg−1 on a wet weight basis. The total concentrations of PCBs at each site ranged from n.d. to 5.41ngg−1 of wet weight. The most heavily contaminated site was the Nakdong estuary located near the Shinpyung-Janglim factory district. The PCB 153 and 138 were the principal congeners and penta- and hexa-chlorinated biphenyls comprised the main congener groups. [Copyright &y& Elsevier]

Four chlorobenzenes (chlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, p-chloro-methylbenzene) were administrated to the crucian carps (Carassius auratus) by peritoneal injections in the laboratory for 30 days. Serum testosterone and 17β-estradiol concentrations were detected using radioimmunology assay (RIA), and the activities of two hepatic microsome enzymes, glutathione s-transferase (GST) and UDP-glucuronosyltransferase (UDPGT), were measured using the modified methods as described by Habig and Owens. Results showed that the four chlorobenzenes caused significant increases in serum testosterone concentration in the crucian carps (P<0.05) compared to the controls, but they caused no significant effect on 17β-estradiol level. All test chemicals caused a change in hepatic GST activity in crucian carps, with significant increases in enzyme activity (P<0.05). Chlorobenzene, 1,3-dichlorobenzene and p-chloro-methylbenzene resulted in a marked inhibition to UDPGT activity in crucian carp (P<0.05) except 1,4-dichlorobenzene. The changes in hepatic microsome enzyme activities may have resulted in the alterations of serum sex steroids levels in the crucian carps. The results indicated that these four chlorobenzenes may result in the changes of endocrine functions and may affect the reproductive success of this and other species. [Copyright &y& Elsevier]

Vitellogenin (VTG) is typically produced by females but when present in males can indicate contamination with estrogenic endocrine-disrupting chemicals (EDCs). Here we used primary hepatocytes isolated from male crucian carp uncontaminated with estrogenic EDCs as a culture model. Nine EDCs were used for validation, and an enzyme-linked immunosorbent assay (ELISA) was used to quantify VTG production by primary hepatocytes. The lower limit of detection of 17β-E2, DES, and HES using the method was 10−12 M. Fresh pork was roasted, and non-hydrolytic acetonitrile-vortexing was used to extract potential estrogenic EDCs. The extracted substances were separated by thin-layer chromatography (TLC), and dimethyl terephthalate present in roast pork was found to induce high VTG concentrations. Therefore, the detection of VTG by ELISA provides a sensitive and reliable method for detecting known and unknown estrogenic EDCs in food products. Image 1 • Estrogenic EDCs can induce VTG expression in primary hepatocytes of male crucian carp. • ELISA was applied to detect VTG after hepatocyte exposure. • Dimethyl terephthalate was detected in a roasted meat product using the new technique. [ABSTRACT FROM AUTHOR]

Previous studies demonstrated that gibel carp A strain was more susceptible to herpesvirus infection than other strains. Thus, we hypothesized that F strain might display better defense responses than the A strain against cadmium (Cd) exposure. To test our hypothesis, gibel carp A strain and F strain were exposed to three diets comprising of different concentrations of Cd for 8 weeks to compare their resistances to Cd. Comprehensive evaluations on biochemical, physiological and histological responses were conducted post-exposure. Results showed that no adverse effects and differences were observed on growth in two strains of gibel carp, compromising of the remarkable hepatoxicity-caused liver damage as shown by histological observations. Dietary Cd exposure stimulated antioxidant defense in the liver to counteract the Cd hepatoxicity, especially in the F strain. Activation of ER stress response positively stimulated the autophagy, then triggering apoptosis in fish after dietary Cd exposure. Thus, Cd-induced autophagy served as a protective strategy to alleviate hepatoxicity, but overaction of ER stress also triggered irreparable cell death via apoptosis. Cd induced dysregulation of lipid accumulation, which might be a common mechanism in response to hepatoxicity. Last but not least, the F strain showed stronger response on antioxidant, ER stress and autophagy, but apoptosis were remitted compared with the A strain, implying the F strain showed stronger response but better defense strategies to dietary Cd exposure. Our finding provides useful information for genetic breeding in aquaculture, and ultimately contribute to the safety assessment of aquatic products for human consumption. Image 1 • Antioxidant responses may be one mechanism to counter Cd toxicity. • Apoptosis resulting from Cd exposure is implicated with ER stress and autophagy. • Chronic dietary Cd triggered lipid accumulation in gibel carp. • F strain showed better defense strategies against Cd exposure than A strain. [ABSTRACT FROM AUTHOR]

Diclofenac (DCF), a non-steroidal anti-inflammatory drug, is widespread in aquatic environments and coexists with heavy metals to form combined pollution. However, the interactive effects of DCF and heavy metals on aquatic organisms remain unknown. This study aimed to investigate the interactive effects of DCF and copper (Cu) on the bioconcentration, oxidative stress status and detoxification-related gene expression in crucian carp (Carassius auratus). Fish were exposed to Cu (100 μg L−1) and DCF (1, 10, 100 and 1000 μg L−1) alone or in combination for 7 days. Results obtained showed that the treatment of Cu combined with high levels of DCF (100 and 1000 μg L−1) significantly decreased tissue concentrations of DCF and Cu compared to the correspondingly individual exposure. Concerning oxidative stress status, as reflected by the activities of antioxidant enzymes and malondialdehyde content, low exposure concentrations of DCF (1 and 10 μg L−1) seemed to mitigate the oxidative stress induced by Cu, whereas the co-exposure of Cu with the highest level of DCF (1000 μg L−1) led to stronger oxidative damage in fish liver than Cu exposure alone. With regarding to detoxification-related genes, in most cases, the expressions of cyp 1a , cyp 3a , gstα , gstπ , pxr and P-gp in crucian carp were significantly altered upon exposure to the compounds in combination compared to exposure to the compounds individually. Collectively, these findings indicate the capacity of each of these pollutants to alter bioconcentration potential, pro-oxidative effects and detoxification-related gene responses of the other when both co-occur at specific concentrations. Image 1 • Interactive effects of DCF and Cu on crucian carp were studied. • Alleviated accumulation of DCF and Cu were observed in the combination treatment. • Co-exposure to Cu and DCF at high levels provoked severer hepatic oxidative stress. • Mixtures changed detoxification related gene expressions compared to individuals. [ABSTRACT FROM AUTHOR]