Hepatic biomarkers of sediment-associated pollution in juvenile turbot, Scophthalmus maximus L

Hatchery-reared turbot (Scophthalmus maximus L.) were exposed for 3 weeks, under laboratory conditions, to sediment collected from polluted sites in Cork Harbour and a reference site at Ballymacoda, Co. Cork, Ireland. The potential of surficial sediment for inducing hepatic biomarkers was assessed at two levels of biological organisation: expression of cytochrome P450 [Western blotting analysis and 7-ethoxy-resorufin O-dealkylase (EROD), 7-benzoxy resorufin O-dealkylase (BROD), 7-methoxy resorufin O-dealkylase (MROD), 7-pentoxy-resorufin O-dealkylase (PROD) activities] and DNA integrity (Comet assay). Positive controls were generated, either by exposing turbot to cadmium chloride-spiked seawater (Comet assay) or to beta-naphthaflavone by intraperitoneal injection (cytochrome P450 induction). The induction of cytochrome P450 activity (EROD, MROD and PROD) in animals following a 7-day exposure to contaminated sediments was significantly higher than those exposed to reference site sediment and remained elevated thereafter; BROD was not induced. DNA single-strand breaks were also significantly higher following exposure to contaminated sediments throughout the experiment. Although no direct correlation between induction of alkoxyresorufin O-dealkylase activities and a particular chemical class was established, the induction of MROD and PROD activities in fish exposed to sediments containing complex contaminant mixtures, appeared to be more sensitive than conventional EROD activity assays. We conclude from the present laboratory study that S. maximus is a suitable sentinel species for the assessment of moderately contaminated sediments and therefore allows for the further development of this model for future, ecologically relevant, field studies.     

Effects of tributyltin at environmental levels on monooxygenase system of digestive gland in hard clam Meretrix meretrix

The effects on ethoxyresorufin O-deethylase （EROD）, NADPH-cytochrome c reductase and NADH cytochrorne b5 reductase activities of digestive gland in Meretrix meretrix exposed to tributyltin （TBT） at environmental levels （0.1,1.0,10.0 ng/dm as stannum concentration）,in experimental condition, were evaluated. The EROD, NADH cytochrorne b5 reductase activities were significantly inhibited after exposure to 10.0 ng/dm^3 TBT for 8 and 20 d, the NADPH cytochrorne c reductase activities were significantly inhibited after exposure to 0.1,1.0 and 10.0 ng/dm TBT for 8 d and to 1.0 and 10.0 ng/dm for 20 d, as compared with the matched control, while NADH cytochrorne b5 reductases and NADPH cytochrome c reductase activities were induced after exposure to 10.0 ng/dm^3 TBT for 2 d. The EROD activity in the 10 ng/dm^3 group,and the NADH cytochrome b5 reductases activities in 1.0 and 10.0 ng/dm groups, were significantly induced when transferred to clean recovery tanks for 7 d. The three enzymic activities in the clams exposed to TBT were recovered to the level corresponding to that of the control group after transfer to clean recovery tanks for 20 d. NADPH cytochrome c reductase activity in Meretrix meretrix seems to be more sensitive to exposure of TBT than that of the EROD and NADH cytochrome b5 reductases. The results suggest that induction and inhibition by TBT to the monooxygenase system enzymic activity in Meretrix meretrix would simultaneously exist. The enzymic activities were inhibited by exposure for a long time. The results suggest that inhibition of the monooxygenase system should be an indication of the exposure to environmentally relevant concentrations of TBT for a long time.     

Contaminant exposure and effects in Baltic ringed and grey seals as assessed by biomarkers

The Baltic Sea ecosystem has suffered from a heavy pollutant load for more than three decades. Persistent organic pollutants (POPs) and heavy metals have been of most concern due to their persistence and toxic properties. Ringed seals (Phoca hispida baltica) and grey seals (Halichoerus grypus) living in the Baltic Sea have been suffering from pathological impairments, including reproductive disturbances, which have resulted in a depressed reproductive capacity. We investigated several biochemical parameters as potential biomarkers for exposure to and effects of the contaminant load in the Baltic seals. Seals from less polluted areas were used as reference material in terms of the pollution load. In both Baltic seal populations, the levels of some biochemical parameters diverged from those in the reference seals, and some of these showed a clear correlation with the individual contaminant load. Of the potential bioindicators, we propose cytochrome P4501A activity and vitamin E levels, in blubber or plasma, as exposure biomarkers for polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT) in both species. The arylhydrocarbon receptor-mediated chemical-activated luciferase gene expression (CALUX) response reflects the whole PCB and DDT burden in ringed seals. Retinyl palmitate (vitamin A) levels showed a negative correlation with the individual POP load, and is proposed as potential effect biomarkers for the depletion of the vitamin A stores. As the nutritional levels of both vitamin A and E have an impact on the vitamin levels in the seals, more information on the dietary vitamin levels is needed before any conclusions can be drawn. As the relationship between biochemical parameters and contaminants varied between the two species, species-specific characteristics has to be considered when monitoring the health status and possible toxic effects of the contaminant load in ringed and grey seals.     

Effects of tributyltin at environmental levels on monooxygenase system of digestive gland in hard clam Meretrix meretrix

The effects on ethoxyresorufin O-deethylase (EROD), NADPH-cytochrome c reductase and NADH cytochrome b5 reductase activities of digestive gland in Meretrix meretrix exposed to tributyltin (TBT) at environmental levels (0.1,1.0, 10.0 ng/dm3 as stannum concentration), in experimental condition, were evaluated. The EROD, NADH cytochrome b5 reductase activities were significantly inhibited after exposure to 10.0 ng/dm3 TBT for 8 and 20 d, the NADPH cytochrome c reductase activities were significantly inhibited after exposure to 0.1,1.0 and 10.0 ng/dm3 TBT for 8 d and to 1.0 and 10.0 ng/dm3 for 20 d, as compared with the matched control, while NADH cytochrome b5 reductases and NADPH cytochrome c reductase activities were induced after exposure to 10.0 ng/dm3 TBT for 2 d. The EROD activity in the 10 ng/dm3 group, and the NADH cytochrome b5 reductases activities in 1.0 and 10.0 ng/dm3 groups, were significantly induced when transferred to clean recovery tanks for 7 d. The three enzymic activities in the clams exposed to TBT were recovered to the level corresponding to that of the control group after transfer to clean recovery tanks for 20 d. NADPH cytochrome c reductase activity in Meretrix meretrix seems to be more sensitive to exposure of TBT than that of the EROD and NADH cytochrome b5 reductases. The results suggest that induction and inhibition by TBT to the monooxygenase system enzymic activity in Meretrix meretrix would simultaneously exist. The enzymic activities were inhibited by exposure for a long time. The results suggest that inhibition of the monooxygenase system should be an indication of the exposure to environmentally relevant concentrations of TBT for a long time.     

三丁基锡对文蛤外套膜代谢酶活性的影响

用实验生态学方法，观察浓度为0．1、1、10ng／dm^3的三丁基锡暴露2、8、20d以及恢复7、20d后对文蛤外套膜酸性磷酸酶、碱性磷酸酶以及Na^＋、K^＋-ATP酶活性的影响．结果表明各浓度组的三丁基锡在暴露早期（2d），外套膜中酸性、碱性磷酸酶和Na^＋、K^＋-ATP酶活性与对照组比较没有显著差异，随着暴露时间的延长，高浓度的TBT暴露对AKP表现出激活作用，对ACP和Na^＋、K^＋-ATP酶活性则具有抑制作用．结果显示Na^＋、K^＋-ATP酶可作为有机锡暴露的生物标志物．     

Distribution of cytochrome P4501A (CYP1A) in the tissues of Baltic ringed and grey seals

Information about the expression of CYP1A in wildlife species is essential for understanding the impact of organochlorine exposure on the health status of an exposed population. Therefore, we aimed at characterising a putative CYP1A enzyme expression in both hepatic and extrahepatic tissues of ringed and grey seals from the Baltic Sea and from less polluted waters. The cellular localisation of CYP1A was identified using a monoclonal antibody against scup P4501A1 (MAb 1-12-3). Immunohistochemical staining showed the highest level of CYP1A expression in liver hepatocytes, and the second highest level in the endothelial cells of capillaries and larger blood vessels in the liver and other organs. The most frequent and strongest staining was found in Baltic ringed seals. Although CYP1A-positive staining was observed in only a few tissues in the other seal populations, it was more intense in Baltic grey seals than in Canadian grey seals. The CYP1A enzyme activity, expressed as ethoxyresorufin O-deethylation (EROD), followed a similar tissue distribution and geographical pattern as the immunohistochemistry with clearly elevated EROD activities in most tissues of both Baltic seal populations. Immunochemical characterisation by immunoblotting confirmed the presence and elevation pattern of a putative CYP1A protein in ringed and grey seals, supporting our findings using other methods. The evenly distributed elevation of CYP1A expression among most of the tissues examined indicates that Baltic seals are exposed to CYP1A inducing agents affecting the whole body. This may result in an increased or decreased toxic potential of foreign substances, which may ultimately determine the biological effects of the contaminants.     

Food and feeding habits of juvenile flounder Platichthys flesus (L.), abd turbot Scophthalmus maximus L. in the åland archipelago, northern Baltic Sea

The food choice of juvenile flounder (Platichthys flesus) and turbot (Scophthalmus maximus) was studied in the northern Baltic Sea during the years 1988, 1989, 1994 and 1995. The diet included organisms from 30 species/taxa in flounder (n = 306) and 10 species/taxa in turbot (n = 41). Flounder 45 mm mainly consumed meiofauna (dominating taxon: Harpacticoida, Copepoda) and larger fish (46–101 mm) consumed macrofauna (dominating taxa: Oligochaeta, Amphipoda and Chironomidae). In terms of biomass, macrofauna dominated for all sizes of flounders, and meiofauna was important only for the smallest fish. A strong seasonal variation could be detected in the diet. In spring, macrofauna dominated for all size classes of fish (only fish > 30 mm were caught in spring), while in summer and autumn meiofauna dominated the diets for fish 45 mm in size. Juvenile turbot (22–88 mm) consumed macrofauna and small fish. Turbot 30 mm consumed mainly amphipods, while > 30 mm turbot consumed mysid shrimps, amphipods and fish.The ontogenetic shift from meio- to macrofauna-sized prey in flounders occurs at a larger fish size in the northern Baltic Sea than reported in other areas, possibly depending on the increased relative importance of meiofauna in the northern Baltic. The seasonal variation in the diet could be due to seasonally changing abundances in the zoobenthos, or for the small fish (1-group, spring), to switching from meio- to macrofauna in order to optimize their energy gain. The 0-group flounders consumed meiofauna for a long period, possibly due to a learning-process or simply due to easy availability of meiofauna. Turbot has a much larger mouth gap than flounders, thus allowing them to consume macrofauna from the beginning of their benthic life.     

Feeding habits of juvenile flatfish in relation to habitat characteristics in the Baltic Sea

To investigate feeding habits of juvenile flounder (Platichthys flesus) and turbot (Psetta maxima) in relation to habitat characteristics a field survey with push net sampling was conducted in nursery areas with different ecological characteristics in the northern Baltic proper. Sampling sites were stratified to cover several different habitat types defined by substrate and wave exposure. Apart from flatfishes and epifauna, samples of macrofauna, meiofauna and hyperbenthic planktons were collected from each site together with data on vegetation, depth, salinity, temperature and turbidity. The diet differed between species where flounder diet was dominated by chironomids, copepods and oligochaetes while turbot apart from chironomids had a high incidence of amphipods, gobies and mysids. In both species there was a shift in diet with size, although this shift was influenced by the habitat. Among the environmental variables investigated, wave exposure was found to significantly influence flounder diet. Food preference in the most exposed areas was dominated by oligochaetes and copepods instead of chironomids, which dominated in sheltered areas. This study shows that habitat characteristics can have a major influence on feeding habits of juvenile flatfish.     

Ethoxyresorufin-O-deethylase activity and fixed wavelength fluorescence detection of PAHs metabolites in bile in turbot (Scophthalmus maximus L.) Exposed to a dispersed topped crude oil in a Continuous Flow System

Long term effects of sublethal concentrations of oil on the marine environment have become of general concern. Cytochrome P4501A activity (EROD) in liver and fixed wavelength fluorescence detection of PAHs metabolites (FF) have in this study been used as biomarkers for dispersed oil exposure on a long term period of juvenile turbot (Scophthalmus maximus L.). A Continuous Flow System was used to carry out the study. The fish were continuously exposed to 0.125, 0.5 or 2.0 mg litre⁻¹ dispersed topped crude oil for 6, 15, 24 h, 4 and 21 days followed by a 9 days recovery period in clean seawater. No induction of the cytochrome P4501A was measured. A maximum level in bile metabolites (4- to 5-fold) was recorded after 24 h of exposure revealing thereby a detoxification process, but a decline occurred from day 4 to day 21. This study demonstrated that FF detection of PAHs metabolites in bile could be a more sensitive biomarker than EROD activity in a long term exposure to sublethal concentration of oil.     

酚类污染物对菲律宾蛤仔抗氧化和解毒系统相关酶活性的影响

壬基酚、辛基酚、二氯酚和双酚A是水环境中普遍存在的酚类污染物,由于其内分泌干扰活性和致癌性近年来受到广泛的关注.本研究以菲律宾蛤仔(Ruditapes philippinarum)为受试生物,研究4种典型酚类污染物暴露对其内脏组织和鳃组织中抗氧化酶包括超氧化物歧化酶(SOD)和过氧化氢酶(CAT)以及解毒酶谷胱甘肽硫转移酶(GST)活性的影响.研究结果表明:壬基酚低浓度处理组(0.05～0.2 mg/L)3种酶活性无显著变化,高浓度处理组(0.4 mg/L),SOD、CAT和GST 3种酶活性均受到显著抑制,抑制率分别为56.6％,59.0％和35.5％.在实验浓度范围(0.05～0.4 mg/L)内,二氯酚能够显著抑制内脏组织CAT活性,双酚A能够显著抑制鳃组织GST活性.3种酶活性变化对于酚类污染物的响应呈现较好的规律性,因此可以作为生物标志物联合指示水体中的酚类污染.     

Aldehyde dehydrogenase and glucose-6-phosphate dehydrogenase as markers for enzyme-altered foci in the liver of dab (Limanda limanda L.)

The activities of the most important aldehyde oxidizing enzymes, the aldehyde dehydrogenases (ALDH), were detected histochemically in liver cryosections of dab (Limanda limanda L.) caught at differently polluted stations along the North Sea coast. In parallel, glucose-6-phospate dehydrogenase (G6PDH) as an NADPH-generating enzyme was measured. Increased activities of both enzymes localized putatively preneoplastic hepatocytes (foci), but ALDH in combination with propionaldehyde and NAD marked 50% more foci than G6PDH alone. Nevertheless, at the more contaminated stations with highest prevalences of foci, ALDH activities showed a shift in substrate and coenzyme dependence from propionaldehyde and NAD to benzaldehyde and NADP in altered hepatocytes, a possible result of physiological adaption to the toxic environment. Increased G6PDH activities in focal hepatocytes indicated elevated NADPH production in contrast to the injured extrafocal liver parenchyma showing reduced G6PDH activities compared to normal livers. Using the ALDH inhibitor disulfiram, the existence of a specific tumor-associated isozyme previously found in rats could not be clearly demonstrated in early enzyme-altered hepatocellular foci of dab. However, based on the total inhibition of Bz-NADP-dependent ALDH, the presence of a xenobiotic-induced ALDH isozyme can be anticipated.     

大菱鲆趋化因子CCL34基因的鉴定及其响应细菌感染的表达特征

为了研究大菱鲆(Scophthalmus maximus)中趋化因子(Chenokine)的特征及其在大菱鲆免疫过程中发挥的作用,设计了本文中的实验。本实验从大菱鲆基因组和转录组数据库中鉴定了一个硬骨鱼特有的趋化因子CC亚家族成员—CCL34,并选取大菱鲆的8个健康组织以及2种细菌感染后的肠道和皮肤组织,采用实时荧光定量PCR(qRT-PCR)对其表达特征进行研究。序列分析结果显示该趋化因子全长mRNA包含1个327 bp的5’非编码区(UTR),1个246 bp的3’非编码区,和1个编码103个氨基酸残基长度为312 bp的开放阅读框(ORF)。此CCL34基因含有4个外显子和3个内含子。通过系统发育分析、共线性分析,将该大菱鲆趋化因子命名为CCL34。实时荧光定量PCR表明CCL34在大菱鲆健康组织中普遍表达,尤其在肾脏、肝脏、皮肤中有高水平表达。鳗弧菌(Vibrio anguillarum)和无乳链球菌(Streptococcus agalactiae)感染后,肠道组织CCL34基因表达量较对照组显著性上调(p<0.05),这表明CCL34可能在大菱鲆的肠道粘膜免疫中起重要作用。本研究为趋化因子家族功能的研究奠定了基础,为增强鱼类免疫力和抗病能力提供了理论依据。     

Comparison of organotin accumulation in the masu salmon Oncorhynchus masou accompanying migratory histories

In order to examine the accumulation pattern of organotin compounds (OTs) accompanying the migration pattern in diadromous fish, tributyltin (TBT) and triphenyltin (TPT) compounds and their derivatives were determined in the liver, muscle, gill, and ovary tissues of both sea-run and freshwater-resident masu salmon, which are of the same species, Oncorhynchus masou. Their migratory histories were estimated using strontium (Sr) and calcium (Ca) analysis in the otolith. A significant difference in the mean Sr:Ca ratio from the core to the edge of the otolith was found between sea-run and freshwater-resident masu salmon. The TBT concentration in the liver was significantly higher than that in the other tissues in both sea-run and freshwater-resident fishes. In sea-run masu salmon, the TBT concentrations in all tissues except for the ovary were significantly higher than in those of freshwater-resident individuals. In the sea-run type, the percentage of TBT was higher than that of the freshwater-resident type. The TPT concentration in the liver of the sea-run type was also significantly higher than that in the other tissues, while that in the gill of the freshwater-resident type was significantly higher than that in the other tissues except for the ovary. The TPT concentrations found in the liver and muscle of the sea-run type were significantly higher than those in the freshwater-resident type, whereas the values of the gill in the sea-run type were significantly lower than those in the freshwater-resident fish examined. The percentage of TPT in the sea-run type was higher than that of the freshwater-resident type. These results suggest that the sea-run O. masou has a higher ecological risk of TBT and TPT exposure than the freshwater-residents during their life history.     

大菱鲆仔稚鱼期消化酶及碱性磷酸酶活性的变化

针对海水鱼类仔稚鱼期高死亡率的现状,本实验采集不同发育阶段的大菱鲆,分析测定了酸、碱性蛋白酶、淀粉酶和脂肪酶以及消化道碱性磷酸酶的活性变化,以期为提高大菱鲆仔稚鱼期的成活率和生长率以及优化饵料配方提供理论依据。结果表明,大菱鲆初孵仔鱼体内就已具有碱性蛋白酶活性,而酸性蛋白酶活性在15日龄左右胃腺出现时才测得。蛋白酶活性的3个极低值分别出现于仔鱼开口期,卵黄囊完全消失期和仔鱼向稚鱼的转变期。早期仔鱼体内表现出较强的淀粉酶活性。5日龄时其活性急剧下降,并一直保持较低的比活力水平。脂肪酶活性在仔稚鱼期一直很弱,进入幼鱼期后比活力迅速升高。碱性磷酸酶活性从初孵到50日龄左右始终保持较小幅度的上升,直到60日龄变态完成时才出现大幅度的升高。大菱鲆仔稚鱼发育过程中,消化道中各种酶活性变化显著,仔稚鱼变态完成后,蛋白酶、脂肪酶和碱性磷酸酶活性显著增强,这标志着大菱鲆由稚鱼期向幼鱼期的转变及消化机能的完善。     

三氯异氰尿酸对剑尾鱼(Xiphophorus helleri)毒性及其抗氧化酶影响

采用生物毒性测试与评价方法对常用消毒剂药物三氯异氰尿酸（Trichloroisocyanuric acid,TCCA）对剑尾鱼的急性毒性及其Ⅰ、Ⅱ相代谢酶活性影响进行了研究。结果表明,TCCA对剑尾鱼的96hLG0为2．15mg／L。TCCA对剑尾鱼肝脏还原型谷光苷肽（GSH）、谷胱苷肽硫转酶（GST）和7。乙氧基异吩恶唑酮-脱乙基酶（EROD）都存在诱导作用。雌雄个体在GST和EROD的诱导响应时间有显著差异性,其中雄性个体GST对TCCA暴露响应比雌性个体敏感。     

Effects of pulp bleach plant effluents on hepatic xenobiotic biotransformation enzymes in fish: Laboratory and field studies

The present preliminary report on studies of the influence of pulp bleach plant effluents on hepatic biotransformation enzymes in fish is a part of a major characterisation of biochemical and physiological effects of effluents from pulp industries in Sweden. Our studies on the xenobiotic biotransformation enzymes demonstrate, so far, that the pulp effluents have the potential to strongly induce 7-ethoxyresorufin-O-deethylase activity (EROD) in fish liver and that fish living in the receiving water of an effluent from a pulp bleach plant have induced hepatic EROD activities as well as higher hepatic UDP glucuronyltransferase activities than those living in an unpolluted area. It is thus apparent that measures of induction of biotransformation enzymes in fish liver may be a useful approach in monitoring the presence of potential hazardous compounds released from pulp industries.     

Tributyltin and triphenyltin induce spermatogenesis in ovary of female abalone,Haliotis gigantea

Two-month flow-through exposure experiments of tributyltin (TBT) and triphenyltin (TPhT) were conducted with abalone, Haliotis gigantea. Nominal concentrations of 100 ng TBT/l and 100 ng TPhT/l caused significant spermatogenesis in ovaries of exposed females. There were also significantly more contracted primary oocytes observed in females exposed to either TBT or TPhT than controls. The incidence of two types of unknown cells was also significant in females exposed to TPhT. No significant histological changes were observed in testis of exposed males. This ovarian spermatogenesis caused by TBT and/or TPhT resembles gastropod imposex. Remarkably high concentrations of TBT and TPhT were observed in the head (including central nervous system ganglia), compared to muscles concentrations. Accumulation of TBT and TPhT in the head may disturb reproductive hormonal regulators through neuropeptides released from ganglia. This, as well as possible aromatase inhibition, may be one of the inducers for spermatogenesis in the abalone ovaries.     

Exposure to hydrocarbons 10 years after the Exxon Valdez oil spill: evidence from cytochrome P4501A expression and biliary FACs in nearshore demersal fishes

Three biomarkers of hydrocarbon exposure, CYP1A in liver vascular endothelium, liver ethoxyresorufin O-deethylase (EROD), and biliary fluorescent aromatic compounds (FACs), were examined in the nearshore fishes, masked greenling (Hexagrammos octogrammus) and crescent gunnel (Pholis laeta), collected in Prince William Sound, Alaska, 7-10 years after the Exxon Valdez oil spill (EVOS). All biomarkers were elevated in fish collected from sites originally oiled, in comparison to fish from unoiled sites. In 1998, endothelial CYP1A in masked greenling from sites that were heavily oiled in 1989 was significantly higher than in fish collected outside the spill trajectory. In 1999, fishes collected from sites adjacent to intertidal mussel beds containing lingering Exxon Valdez oil had elevated endothelial CYP1A and EROD, and high concentrations of biliary FACs. Fishes from sites near unoiled mussel beds, but within the original spill trajectory, also showed evidence of hydrocarbon exposure, although there were no correlations between sediment petroleum hydrocarbon and any of the biomarkers. Our data show that 10 years after the spill, nearshore fishes within the original spill zone were still exposed to residual EVOS hydrocarbons.     

The liver of wrasse - morphology and function as a mirror of point source chemical impact.

Corkwing wrasse (Symphodus melops L.), a protogynous, non-migratory lipfish species, living close to rocky shores was chosen as an indicator species for the monitoring of biological effects of contaminants. Fish were caught by local fisherman at the Norwegian west coast in fjord sites within the framework of the EU BEEP project. The sites represented different point source impacts of (I) copper (a former copper mine), (II) polycyclic aromatic hydrocarbons (PAHs, aluminium smelter discharge), (III) formaldehyde plus PAHs (kelp-factory and influence of the aluminium smelter). Livers of wrasse were studied for histopathological alterations and compared to healthy livers of fish from a reference location. Besides liver morphology, different functional and metabolic parameters were measured to link pathological alterations to functional disorders. The integrity of the lysosomal compartment was tested by the assessment of lysosomal membrane stability (lys), and the accumulation of neutral lipids and lipofuscin. Activity and intracellular localisation of the NADPH-producing enzymes in the liver were assessed histochemically and measured by computer-assisted image analysis. Histopathological alterations were most severe at the site impacted by formaldehyde and PAHs. These findings were associated with highest tumor prevalence, lowest membrane stabilities in hepatocytes and highest accumulation rates of lipofuscin in the liver. The activities of the NADPH-producing enzymes phosphogluconate dehydrogenase (PGDH) and glucose-6-phosphate dehydrogenase (G6PDH) were significantly lower compared to unimpacted reference fish. Histopathological alterations showed clear differences dependent on the input source. Potential links between specific contaminant impact and functional and morphological disorders are discussed.