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Several studies demonstrated adverse effects associated with exposure to polystyrene nanoplastics (NPs), such as toxicity, inflammation, or other health-related concerns. This study aims to analyse the impact of NPs exposure on pro-inflammatory cytokine levels and testicular histology in tilapia gonads. Twenty-four male tilapias were used in this study and divided into four groups, including a control (commercial pellets only) and three treatment groups (commercial feed mixed 0.5, 1.0 and 2.0 µL/kg of NPs, respectively) for 25 days. Blood sample was used to tumor necrosis factorα (TNF-α) and interferon-γ (IFN-ɣ) levels analysis. Histology of testicular tissue was prepared with hematoxylin and eosin (HE) staining. The results showed that NPs exposure has no significant influence of TNF-α and IFN-ɣ levels. The levels of TNF-α on the control (1.6 ± 0.3 ng/mL) and the treatment groups from low to high concentration (1.7± 0.4; 1.7 ± 0.4; and 1.6 ± 0.3 ng/mL) and the levels of IFN-γ control (16.7 ± 2.8 ng/mL) and the treatment groups (19.1 ± 5.3; 18.7 ± 4.2; and 19.8 ± 3.5 ng/mL). Polystyrene nanoplastics exposure can reduce the number of spermatogenic cells. Spermatogonia cells was decreased from 27.5 ± 0.9 to 13.1 ± 1.1 cells/cyst. Spermatocyte cell was decreased from 57.6 ± 0.6 to 18.5 ± 0.3 cells/cyst. Spermatid cells was decreased from 86.8 ± 2.7 to 38.5 ± 2.7. In conclusion, exposure to multiple doses of NPs for 25 days did not increase pro-inflammatory cytokines levels in the blood serum of tilapia, but it caused histological changes in the gonads of fish. [ABSTRACT FROM AUTHOR]

The present study was carried out to determine the effect of sub-lethal concentration of treated textile bleaching effluent on the carbohydrate content in gill, liver, muscle and intestine of Cyprinus carpio after 28 days of exposure. A Significant decrease in carbohydrate content was observed in muscle, gill, liver and intestine of effluent treated fish compared to control fish. Liver tissue showed maximum decline in carbohydrate content followed by muscle, intestine and gill. Reduction in carbohydrate content could have happened by increased utilization of it under chronic stress by rapid glycogenolysis or by the inhibition of glycogenesis. In conclusion, the treated textile bleaching effluent containing toxic contaminants induced stress and reduced the nutritive value of fish. [ABSTRACT FROM AUTHOR]

Benzalkonium chloride (BAC) is a cationic surfactant commonly used as a disinfectant, and is discharged into the aquatic environment by various water sources such as wastewater. BAC may also interact with potentially toxic substances such as persistent organic chemicals. Although studies of BAC contamination toxicity and bioaccumulation have been widely reported, the biochemical responses to BAC toxicity remain incompletely understood, and the detailed molecular mechanisms are largely unknown. In this study, two-dimensional gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry-based proteomic approaches were applied to investigate the protein profiles in Oryzias latipes (medaka) chronically exposed to BAC. Fish were exposed to three different concentrations of BAC, 0.05, 0.1, and 0.2 mg/L, for 21 days. A total of 20 proteins involved in the cytoskeleton, the oxidative stress response, the nervous and endocrine systems, signaling pathways, and cellular proteolysis were significantly upregulated by BAC exposure. The proteomic information obtained in the present study will be useful in identification of potential biomarkers for BAC toxicity, and begins to elucidate its molecular mechanisms, providing new insights into the ecotoxicity of BAC. [ABSTRACT FROM AUTHOR]

Background: Health risks linked with dioxin in fish remain a complex policy issue. Fatty Baltic fish contain persistent pollutants, but they are otherwise healthy food. We studied the health benefits and risks associated with Baltic herring and salmon in four countries to identify critical uncertainties and to facilitate an evidence-based discussion.Methods: We performed an online survey investigating consumers' fish consumption and its motivation in Denmark, Estonia, Finland, and Sweden. Dioxin and methylmercury concentrations were estimated based on Finnish studies. Exposure-response functions for several health endpoints were evaluated and quantified based on the scientific literature. We also quantified the infertility risk of men based on a recent European risk assessment estimating childhood dioxin exposure and its effect on sperm concentration later in life.Results: Baltic herring and salmon contain omega-3 fatty acids and vitamin D, and the beneficial impact of these fishes on cardiovascular diseases, mortality, and the risk of depression and cancer clearly outweighs risks of dioxins and methylmercury in people older than 45 years of age and in young men. Young women may expose their children to pollutants during pregnancy and breast feeding. This study suggests that even in this critical subgroup, the risks are small and the health benefits are greater than or at least similar to the health risks. Value of information analysis demonstrated that the remaining scientific uncertainties are not large. In contrast, there are several critical uncertainties that are inherently value judgements, such as whether exceeding the tolerable weekly intake is an adverse outcome as such; and whether or not subgroup-specific restrictions are problematic.Conclusions: The potential health risks attributable to dioxins in Baltic fish have more than halved in the past 10 years. The new risk assessment issued by the European Food Safety Authority clearly increases the fraction of the population exceeding the tolerable dioxin intake, but nonetheless, quantitative estimates of net health impacts change only marginally. Increased use of small herring (which have less pollutants) is a no-regret option. A more relevant value-based policy discussion rather than research is needed to clarify official recommendations related to dioxins in fish. [ABSTRACT FROM AUTHOR]

In the upper Hudson River, New York, USA, fish were exposed to polychlorinated biphenyls (PCBs) from the 1940s to 1977, and PCBs still persist in this environment. Yellow perch (Perca flavescens), brown bullhead (Ameiurus nebulosus), smallmouth bass (Micropterus dolomieu), and largemouth bass (M. salmoides) were collected annually from 2003 to 2009 from 1 control site upstream of the PCB discharge locations and from 2 sites downstream from where PCBs were released. Fish PCB concentrations were estimated, and 3 population metrics were examined: 1) relative abundance, 2) weight‐to‐length ratio, and 3) growth. Normalized lipid‐based PCB concentrations at the 2 PCB exposure pools averaged approximately 100 to 600 μg/g. Estimated relative abundances with electrofishing were higher for largemouth bass, smallmouth bass, and brown bullhead at PCB exposure sites compared to the control site; but yellow perch were more abundant at the control site. Weight to length ratios varied among sites and species, but no consistent pattern was evident in relation to PCBs at the population level or for individual fish. Growth rates for yellow perch and brown bullhead were similar among sites. Largemouth bass growth was slightly higher at the control site compared to the 2 PCB sites, but smallmouth bass growth was much higher at the PCB sites compared to the control site. We could not detect any relation or influence of PCBs on the 3 population metrics that we examined. the present results corroborated those of previous investigations concerning the effects of PCBs on fishes. We recommend stronger consideration of the biological impacts of PCBs at the population level when conducting risk assessments. Environ Toxicol Chem 2019;38:329–339. © 2018 SETAC [ABSTRACT FROM AUTHOR]

Abstract This paper provides the first record of ingestion of plastic debris by American lobster, Homarus americanus. Plastics particles, identified as rubber pieces, were found in the stomachs of 3 from 17 individuals of lobsters kept in laboratory conditions. Debris had evidence of cuts, what suggest they were actively consumed. Highlights • First evidence of ingested plastics by a high commercial lobster species Homarus americanus • Plastic particles found in lobster's stomachs were identified as rubber band pieces. • Cuts evidence on plastic debris suggested they were actively consumed. [ABSTRACT FROM AUTHOR]

Background: Qarun and Burullus Lakes suffer from serious pollution problems owing to the enormous input of untreated agricultural, domestic and industrial effluents. This study was conducted to explain the effect of water pollution of these lakes on some physiological parameters of O. niloticus. Results: Showed clearly that water collected from both Qarun and Burullus Lakes were contaminated with high levels of lead and cadmium. The concentration of Pb and Cd in Lake Qarun (0.074 and 0.006 ppm respectively) were much lower than that of Burullus Lake (0.112 and 0.011ppm respectively). The study showed that the rates of Pb bioaccumulations were increased significantly in the muscles of O. niloticus collected from Brurllues Lake than that of Qarun Lake. It can be seen also that there are insignificant differences of Cd concentrations in muscles of tilapians collected from both Lakes. Analysis of liver functions shwoed a highly significant increase in the level of ALT in O. niloticus liver collected from Brurllues Lake than tilapia'sb liver from Qarun Lake. Both AST and GGT levels were insignificantly changed in fishes collected from both Lakes (no change in the table). Investigation of kidney functions of tilapias collected from Qarun and Burullus Lakes showed that urea concentration was significantly increased in kidney of Tilapia gathered from Burullus Lake (32.40 ± 0.93 mg/dl) than those collected from Qarun Lake (28.80 ± 0.73 mg/dl). Creatinine concentrations were significantly increased in kidney of tilapias gathered from Burullus Lake than Qarun Lake. Cholesterol, Triglycerides, high density lipoproteins (HDL), low density lipoproteins (LDL), and very low density lipoproteins (VLDL) in the muscles of tilapians collected from Burllues Lake were highly significant increase while total proteins were significantly decreased in comparison with tilapians of Qaron Lake. [ABSTRACT FROM AUTHOR]

Abstract: A key step in identifying global change impacts on species and ecosystems is to quantify effects of multiple stressors. To date, the science of global change has been dominated by regional field studies, experimental manipulation, meta‐analyses, conceptual models, reviews, and studies focusing on a single stressor or species over broad spatial and temporal scales. Here, we provide one of the first studies for coastal systems examining multiple stressor effects across broad scales, focused on the nursery function of 20 estuaries spanning 1,600 km of coastline, 25 years of monitoring, and seven fish and invertebrate species along the northeast Pacific coast. We hypothesized those species most estuarine dependent and negatively impacted by human activities would have lower presence and abundances in estuaries with greater anthropogenic land cover, pollution, and water flow stress. We found significant negative relationships between juveniles of two of seven species (Chinook salmon and English sole) and estuarine stressors. Chinook salmon were less likely to occur and were less abundant in estuaries with greater pollution stress. They were also less abundant in estuaries with greater flow stress, although this relationship was marginally insignificant. English sole were less abundant in estuaries with greater land cover stress. Together, we provide new empirical evidence that effects of stressors on two fish species culminate in detectable trends along the northeast Pacific coast, elevating the need for protection from pollution, land cover, and flow stressors to their habitats. Lack of response among the other five species could be related to differing resistance to specific stressors, type and precision of the stressor metrics, and limitations in catch data across estuaries and habitats. Acquiring improved measurements of impacts to species will guide future management actions, and help predict how estuarine nursery functions can be optimized given anthropogenic stressors and climate change scenarios. [ABSTRACT FROM AUTHOR]

Several metabolic parameters were assessed in juvenile Chinook salmon ( Oncorhynchus tshawytscha ) and staghorn sculpin ( Leptocottus armatus ) residing in two estuaries receiving wastewater treatment effluent and one reference estuary. We also conducted a laboratory study with fish dosed for 32 days with 16 of the most common contaminants of emerging concern (CECs) detected in feral fish. Several blood chemistry parameters and other indicators of health were measured in fish from the field and laboratory study that were used to assess potential metabolic disruption. The blood chemistry values observed in feral juvenile Chinook salmon were relatively consistent among fish collected from effluent-impacted sites and substantially different compared to reference site fish. These responses were more pronounced in Chinook salmon, which is supported by the disparity in accumulated CECs. The blood chemistry results for juvenile Chinook salmon collected at effluent-impacted sites exhibited a pattern generally consistent with starvation because of similarities to observations from studies of food-deprived fish; however, this response is not consistent with physical starvation but may be contaminant induced. The altered blood chemistry parameters are useful as an early indicator of metabolic stress, even though organismal characteristics (lipid content and condition factor) were not different among sites indicating an early response. Evidence of metabolic disruption was also observed in juvenile Chinook salmon that were exposed in the laboratory to a limited mixture of CECs; however, the plasma parameters were qualitatively different possibly due to exposure route, season, or the suite of CECs. Growth was impaired in the high-dose fish during the dosing phase and the low- and medium-dose fish assayed after 2 weeks of depuration. Overall, these results are consistent with metabolic disruption for fish exposed to CECs, which may result in early mortality or an impaired ability to compete for limited resources. [ABSTRACT FROM AUTHOR]

Dicamba (DIC) and 2,4-dichlorophenoxyacetic acid (2,4-D) are two of the most applied auxinic herbicides worldwide, both individually and as part of a mixture. However, the toxicity and interactions achieved when applied as a mixture have not yet been characterised. The equitoxic and non-equitoxic acute toxicity exerted by binary mixtures of Banvel ® (57.71% DIC) and DMA ® (58.4% 2,4-D) on the Neotropical fish Cnesterodon decemmaculatus were evaluated. Results revealed mean values of 1.02 (range, 0.96–1.08) for the toxic unit (TU) that induced 50% mortality (TU 50 96 h ) to the fish exposed to binary equitoxic mixtures of the commercial formulations Banvel ® –DMA ® . These results suggest that the mixture is nearly concentration additive. Furthermore, results demonstrated the occurrence of synergistic interaction when non-equitoxic combinations of Banvel ® -or DMA ® -formulated herbicides were assayed. In this context and regardless of their concentrations, either Banvel ® - or DMA ® -induced toxicity were synergised by the presence of the counterpart within mixtures. The present study represents the first evidence of the lethality exerted by mixtures of two auxinic herbicides—namely, DIC and 2,4-D—reported to date for fish and other biotic matrices. When C. decemmaculatus is used as the target organism, a synergistic pattern is observed following exposure to a mixture of both herbicides. [ABSTRACT FROM AUTHOR]

Microplastics are widespread throughout aquatic environments. However, there is currently insufficient understanding of the factors influencing ingestion of microplastics by organisms, especially higher predators such as fish. In this study we link ingestion of microplastics by the roach Rutilus rutilus, within the non-tidal part of the River Thames, to exposure and physiological factors. Microplastics were found within the gut contents of roach from six out of seven sampling sites. Of sampled fish, 33% contained at least one microplastic particle. The majority of particles were fibres (75%), with fragments and films also seen (22.7% and 2.3% respectively). Polymers identified were polyethylene, polypropylene and polyester, in addition to a synthetic dye. The maximum number of ingested microplastic particles for individual fish was strongly correlated to exposure (based on distance from the source of the river). Additionally, at a given exposure, the size of fish correlated with the actual quantity of microplastics in the gut. Larger (mainly female) fish were more likely to ingest the maximum possible number of particles than smaller (mainly male) fish. This study is the first to show microplastic ingestion within freshwater fish in the UK and provides valuable new evidence of the factors influencing ingestion that can be used to inform future studies on exposure and hazard of microplastics to fish. [ABSTRACT FROM AUTHOR]

The Laurentian Great Lakes are a valuable natural resource that is affected by contaminants of emerging concern (CECs), including sex steroid hormones, personal care products, pharmaceuticals, industrial chemicals, and new generation pesticides. However, little is known about the fate and biological effects of CECs in tributaries to the Great Lakes. In the current study, 16 sites on three rivers in the Great Lakes basin (Fox, Cuyahoga, and Raquette Rivers) were assessed for CEC presence using polar organic chemical integrative samplers (POCIS) and grab water samplers. Biological activity was assessed through a combination of in vitro bioassays (focused on estrogenic activity) and in vivo assays with larval fathead minnows. In addition, resident sunfish, largemouth bass, and white suckers were assessed for changes in biological endpoints associated with CEC exposure. CECs were present in all water samples and POCIS extracts. A total of 111 and 97 chemicals were detected in at least one water sample and POCIS extract, respectively. Known estrogenic chemicals were detected in water samples at all 16 sites and in POCIS extracts at 13 sites. Most sites elicited estrogenic activity in bioassays. Ranking sites and rivers based on water chemistry, POCIS chemistry, or total in vitro estrogenicity produced comparable patterns with the Cuyahoga River ranking as most and the Raquette River as least affected by CECs. Changes in biological responses grouped according to physiological processes, and differed between species but not sex. The Fox and Cuyahoga Rivers often had significantly different patterns in biological response Our study supports the need for multiple lines of evidence and provides a framework to assess CEC presence and effects in fish in the Laurentian Great Lakes basin. [ABSTRACT FROM AUTHOR]

In November and December 2016, local residents around St. Mary’s Bay, Nova Scotia, Canada, noticed something alarming: thousands of dead fish were washing up along the coast. Scientists from the Canadian government’s Department of Fisheries and Oceans investigated, but the cause remains a mystery. This research note excogitates a potential cause: dumped chemical and conventional munitions. Between 1918 and 1972, most industrialized countries disposed of surplus munitions at sea. As a result, hundreds of millions of tons of corroded ordnance now pollute marine environments around the world. The article then discusses various research obstacles impeding further scholarly investigations and the possible connections between underwater munitions and the mass death of aquatic life. [ABSTRACT FROM AUTHOR]

The increasing global contamination of plastics in marine environments is raising public concerns about the potential hazards of microplastics to environmental and human health. Microplastics formed by the breakdown of larger plastics are typically irregular in shape. The objective of this study was to compare the effects of spherical or irregular shapes of microplastics on changes in organ distribution, swimming behaviors, gene expression, and enzyme activities in sheepshead minnow ( Cyprinodon variegatus ). Both types of microplastics accumulated in the digestive system, causing intestinal distention. However, when compared to spherical microplastics, irregular microplastics decreased swimming behavior (i.e., total distance travelled and maximum velocity) of sheepshead minnow. Both microplastics generated cellular reactive oxygen species (ROS), while ROS-related molecular changes (i.e., transcriptional and enzymatic characteristics) differed. This study provides toxicological insights into the impacts of environmentally relevant (fragmented) microplastics on fish and improves our understanding of the environmental effects of microplastics in the ecosystem. [ABSTRACT FROM AUTHOR]

The acute toxicity of organic pollutants to fish, Daphnia magna , Tetrahymena pyriformis , and Vibrio fischeri was investigated. The results indicated that the Toxicity Ratio (TR) threshold of log TR = 1, which has been based on the distribution of toxicity data to fish, can also be used to discriminate reactive or specifically acting compounds from baseline narcotics for Daphnia magna and Vibrio fischeri . A log TR = 0.84 is proposed for Tetrahymena pyriformis following investigation of the relationships between the species sensitivity and the absolute averaged residuals (AAR) between the predicted baseline toxicity and the experimental toxicity. Less inert compounds exhibit relatively higher toxicity to the lower species ( Tetrahymena pyriformis and Vibrio fischeri ) than the higher species (fish and Daphnia magna ). A greater number of less inert compounds with log TR greater than the thresholds was observed for Tetrahymena pyriformis and Vibrio fischeri . This may be attributed to the hydrophilic compounds which may pass more easily through cell membranes than the skin or exoskeleton of organisms and have higher bioconcentration factors in the lower species, leading to higher toxicity. Most of classes of chemical associated with excess toxicity to one species also exhibited excess toxicity to other species, however, a few classes with excess toxicity to one species exhibiting narcotic toxicity to other species and thus may have different MOAs between species. Some ionizable compounds have log TR much lower than one because of the over-estimated log K OW . The factors that influence the toxicity ratio calculated from baseline level are discussed in this paper. [ABSTRACT FROM AUTHOR]

The effluent emission from textile industries has become a foremost concern in accordance with the growth of global industrial sectors. Although the textile industries have a major role in economic development, they cause quality deterioration of ecosystems. Several studies have discussed the environmental consequences of textile effluents and attempted to characterize the textile wastewaters. The main pollutants formed from the textile industry include dyes, surfactants, salts, metal complexes, biocides, hydrocarbons, resins, waxes, etc. Most of the pollutants are of aromatic and heterocyclic compounds of stable complicated structure with non-degradability. The water contaminated with textile effluents shows massive variation in water quality. The methods based on qualitative and quantitative observations of living organisms in their natural habitats were efficient in compensating deficiencies of physico-chemical analysis. Therefore, the biological approach arrived in the water quality determination such as bioindicators and biomarkers. Fish are particularly sensitive to the water contamination and, therefore, pollutants may significantly interfere with several of their biochemical processes. So the recent trend in biomarker studies focuses on the behavioural, physiological and biochemical changes of fish. In this review, the impacts of textile effluents on freshwater ecosystems and the fish biomarkers (biochemical, haematological, histological parameters) used for the assessment of these undesirable changes have been discussed. [ABSTRACT FROM AUTHOR]

The herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) is applied directly to aquatic and conventional farming systems to control weeds, and is among the most widely distributed pollutants in the environment. Non-target organisms are exposed to 2,4-D via several ways, which could produce toxic effects depending on the dose, frequency of exposure, and the host factors that influence susceptibility and sensitivity. An increasing number of experimental evidences have shown concerns about its presence/detection in the environment, because several investigations have pointed out its potential lethal effects on non-target organisms. In this review, we critically evaluated the environmental fate and behavior of 2,4-D along with its eco-toxicological effects on aquatic, plants and human life to provide concise assessment in the light of recently published reports. The findings demonstrate that 2,4-D is present in a low concentration in surface water of regions where its usage is high. The highest concentrations of 2,4-D were detected in soil, air and surface water surrounded by crop fields, which suggest that mitigation strategies must be implanted locally to prevent the entry of 2,4-D into the environment. A general public may have frequent exposure to 2,4-D due to its wide applications at home lawns and public parks, etc. Various in vivo and in vitro investigations suggest that several species (or their organs) at different trophic levels are extremely sensitive to the 2,4-D exposure, which may explain variation in outcomes of reported investigations. However, implications for the prenatal exposure to 2,4-D remain unknown because 2,4-D-induced toxicity thresholds in organism have only been derived from juveniles or adults. In near future, introduction of 2,4-D resistant crops will increase its use in agriculture, which may cause relatively high and potentially unsafe residue levels in the environment. The recent findings indicate the urgent need to further explore fate, accumulation and its continuous low level exposure impacts on the environment to generate reliable database which is key in drafting new regulation and policies to protect the population from further exposure. [ABSTRACT FROM AUTHOR]

Environmental toxicology has been expanding as growing concerns on the impact of produced and released chemical compounds over the environment and human health are being demonstrated. Among the toxic effects observed in organisms exposed to pollutants, those affecting skeletal tissues (osteotoxicity) have been somehow overlooked in comparison to hepato-, immune-, neuro- and/or reproductive toxicities. Nevertheless, sub-lethal effects of toxicants on skeletal development and/or bone maintenance may result in impaired growth, reduced survival rate, increased disease susceptibility and diminished welfare. Osteotoxicity may occur by acute or chronic exposure to different environmental insults. Because of biologically and technically advantagous features – easy to breed and inexpensive to maintain, external and rapid rate of development, translucent larvae and the availability of molecular and genetic tools – the zebrafish ( Danio rerio ) has emerged in the last decade as a vertebrate model system of choice to evaluate osteotoxicity. Different experimental approaches in fish species and analytical tools have been applied, from in vitro to in vivo systems, from specific to high throughput methodologies. Current knowledge on osteotoxicity and underlying mechanisms gained using fish, with a special emphasis on zebrafish systems, is reviewed here. Osteotoxicants have been classified into four categories according to the pathway involved in the transduction of the osteotoxic effects: activation/inhibition of membrane and/or nuclear receptors, alteration of redox condition, mimicking of bone constituents and unknown pathways. Knowledge on these pathways is also reported here as it may provide critical insights into the development, production and release of future chemical compounds with none or low osteotoxicity, thus promoting the green/environmental friendly chemistry. [ABSTRACT FROM AUTHOR]

The potential for metals to bioaccumulate in aquatic species, such as fish, via trophic level transfer was investigated. An in vivo experiment was set up in a flow-through system in which juvenile rainbow trout were fed blue mussels collected from a Class A pristine site and an effluent-impacted river estuary, over a period of 28 days. Selected elements (As, Cd, Cr, Co, Cu, Fe, Pb, Mn, Mo, Ni, Se, Sn, V, Zn) were determined in the mussels and fish tissues (muscle and skin) collected at 0, 14 and 28 days. This study reveals the occurrence of metals in mussels sampled in the Irish marine environment and highlights the bioaccumulation potential of metals in fish tissues via trophic transfer. All 14 monitored metals were determined in the mussels collected from both sites and mussels collected from the effluent-impacted site contained three times more Co, Mo, Sn and V than the mussels collected from the Class A site. Following a 28-day dietary exposure, concentrations of As and Se (fish muscle), and Pb, Se and Zn (fish skin), were significantly greater in fish feeding on contaminated mussels compared to those with a regular fish feed diet. The significance of metal detection and bioaccumulation in the mussel and fish tissues, highlights the potential for metal exposure to humans through the food chain. As fish are recommended as a healthy and nutritious food source, it is important to fully understand metal bioaccumulation in commercially important aquatic species and ensure the safety of human consumers. [ABSTRACT FROM AUTHOR]

Most controlled toxicity studies use single chemical exposures that do not represent the real world situation of complex mixtures of known and unknown natural and anthropogenic substances. In the present study, complex contaminant cocktails derived from the blubber of polar bears (PB; Ursus maritimus) and killer whales (KW; Orcinus orca) were used for in vitro concentration-response experiments with PB, cetacean and seal spp. immune cells to evaluate the effect of realistic contaminant mixtures on various immune functions. Cytotoxic effects of the PB cocktail occurred at lower concentrations than the KW cocktail (1 vs 16 µg/mL), likely due to differences in contaminant profiles in the mixtures derived from the adipose of each species. Similarly, significant reduction of lymphocyte proliferation occurred at much lower exposures in the PB cocktail (EC50: 0.94 vs 6.06 µg/mL; P < 0.01), whereas the KW cocktail caused a much faster decline in proliferation (slope: 2.9 vs 1.7; P = 0.04). Only the KW cocktail modulated natural killer (NK) cell activity and neutrophil and monocyte phagocytosis in a concentration- and species-dependent manner. No clear sensitivity differences emerged when comparing cetaceans, seals and PB. Our results showing lower effect levels for complex mixtures relative to single compounds suggest that previous risk assessments underestimate the effects of real world contaminant exposure on immunity. Our results using blubber-derived contaminant cocktails add realism to in vitro exposure experiments and confirm the immunotoxic risk marine mammals face from exposure to complex mixtures of environmental contaminants. [ABSTRACT FROM AUTHOR]

We investigated the protection offered by the probiotic Lactobacillus plantarum CCFM639 against waterborne Al exposure in tilapia. Fish were allocated to control, CCFM639-only, Al-only or Al plus CCFM639 groups. The fish were exposed to 2.73 mg/L Al ions for 4 weeks. The probiotic was incorporated into the fish diet at 10 8 CFU/g and provided twice daily. Our results showed that L . plantarum CCFM639 significantly enhanced feed utilization, growth performance and antioxidant ability in the absence of waterborne Al exposure. When fish were exposed to Al, dietary supplementation with the strain effectively decreased the death rate and accumulation of Al in tissues, and enhanced growth performance. Moreover, Al-induced changes in hematobiochemical parameters and hepatic oxidative stress and histopathology were also alleviated. Therefore, L . plantarum CCFM639 may be a novel dietary supplement for fish to enhance growth performance and prevent aquaculture and food safety problems induced by Al pollution. [ABSTRACT FROM AUTHOR]

We examined whether contaminants present in surface waters could be prioritized for further assessment by linking the presence of specific chemicals to gene expression changes in exposed fish. Fathead minnows were deployed in cages for 2, 4, or 8 days at three locations near two different wastewater treatment plant discharge sites in the Saint Louis Bay, Duluth, MN and one upstream reference site. The biological impact of 51 chemicals detected in the surface water of 133 targeted chemicals was determined using biochemical endpoints, exposure activity ratios for biological and estrogenic responses, known chemical:gene interactions from biological pathways and knowledge bases, and analysis of the covariance of ovary gene expression with surface water chemistry. Thirty-two chemicals were significantly linked by covariance with expressed genes. No estrogenic impact on biochemical endpoints was observed in male or female minnows. However, bisphenol A (BPA) was identified by chemical:gene covariation as the most impactful estrogenic chemical across all exposure sites. This was consistent with identification of estrogenic effects on gene expression, high BPA exposure activity ratios across all test sites, and historical analysis of the study area. Gene expression analysis also indicated the presence of nontargeted chemicals including chemotherapeutics consistent with a local hospital waste stream. Overall impacts on gene expression appeared to be related to changes in treatment plant function during rain events. This approach appears useful in examining the impacts of complex mixtures on fish and offers a potential route in linking chemical exposure to adverse outcomes that may reduce population sustainability. [ABSTRACT FROM AUTHOR]

ABSTRACT Historically, ecological risk assessments have rarely included amphibian species, focusing preferentially on other aquatic (fish, invertebrates, algae) and terrestrial wildlife (birds and mammal) species. Often this lack of consideration is due to a paucity of toxicity data, significant variation in study design, uncertainty with regard to exposure, or a combination of all three. Productive risk assessments for amphibians are particularly challenging, given variations in complex life history strategies. Further consideration is needed for the development of useful laboratory animal models and appropriate experimental test procedures that can be effectively applied to the examination of biological response patterns. Using these standardized techniques, risk estimates can be more accurately defined to ensure adequate protection of amphibians from a variety of stress agents. Patterns in toxicity may help to ascertain whether test results from 1 amphibian group (e.g., Urodela) could be sufficiently protective of another (e.g., Anura) and/or whether some nonamphibian aquatic taxonomic groups (e.g., fish or aquatic invertebrates) may be representative of aquatic amphibian life stages. This scope is intended to be a guide in the development of methods that would yield data appropriate for ecological risk decisions applicable to amphibians. Integr Environ Assess Manag 2017;13:601-613. © 2016 SETAC [ABSTRACT FROM AUTHOR]

The ecotoxicological effects of methylmercury (MeHg) exposure have been intensively described in literature. Yet, it is still unclear how marine biota will respond to the presence of MeHg under climate change, namely ocean warming. The present study aimed to investigate, for the first time, fish condition [Fulton's K index (K), hepatosomatic index (HIS) and brain-to-body mass ratio (BB-ratio)] and several stress-related responses in an ecologically and commercially important fish species ( Dicentrachus labrax ) exposed for 28 days to dietary MeHg (8.0 mg kg-1 dw) and temperature increase (+ 4 °C). Results showed significant impairments on fish condition, i.e. up to 34% decrease on K, > 100% increase on HIS and 44% decrease on BB-ratio, compared to control conditions. Significant changes on tissue biochemical responses were observed in fish exposed to both stressors, acting alone or combined, evidencing the relevance of assessing possible interactions between different environmental stressors in ecotoxicological studies. For instance, muscle showed to be the least affected tissue, only revealing significant alterations in GST activity of MeHg-enriched fish. On the other hand, liver exhibited a significant induction of GST (> 100%) and CAT (up to 74%) in MeHg-enriched fish, regardless of temperature exposure, as well as decreased SOD activity (19%) and increased HSP70/HSC70 content (87%) in fish exposed to warming alone. Brain showed to be affected by temperature (69% of GST inhibition and > 100% of increased CAT activity), MeHg (> 100% of increased CAT activity, 47% of SOD inhibition and 55% of AChE inhibition), as well as by the combination of both (GST, SOD and AChE inhibition, 17%, 48% and 53%, respectively). Hence, our data provides evidences that the toxicological aspects of MeHg ca be potentiated by warmer temperatures, thus, evidencing the need for further research combining contaminants exposure and climate change effects, to better forecast ecological impacts in the ocean of tomorrow. [ABSTRACT FROM AUTHOR]

We measured the concentrations of 60 flame retardants (and related compounds) in fish samples collected in the Great Lakes basin. These analytes include dechlorane-related compounds (Decs), organophosphate esters (OPEs), and brominated flame retardants (BFRs). Composite lake trout ( Salvelinus namaycush ) or walleye ( Sander vitreus , from Lake Erie) samples were collected (N = 3 for each lake) in 2010 from each of the five Great Lakes (a total of 15 samples). Among the dechlorane-related compounds, Dechlorane, Dechlorane Plus, Dechlorane-602, Dechlorane-603, and Dechlorane-604 (with zero to three bromines and with four chlorines) were detected in > 73% of the fish samples. The concentrations of some of these dechlorane-related compounds were 3–10 times higher in Lake Ontario trout than in fish from the other four lakes. Tris(1-chloroisopropyl) phosphate, tri- n -butylphosphate, tris(2-chloroethyl)phosphate, and triphenyl phosphate were found in > 50% of the fish samples. Polybrominated diphenyl ethers (PBDEs) were the most abundant of the flame retardants in fish, with a mean concentration of 250 ng/g lipid. Our findings suggest that the Decs and BFRs with 3–6 bromines are more bioaccumulative in the fish than the OPEs and high molecular weight BFRs. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAH) are environmental contaminants that pose significant risk to health of fish. The International Workshop on Integrated Assessment of Contaminant Impacts on the North Sea (ICON) provided the framework to investigate biomarker responses as well as contaminant concentrations side by side in marine ecosystems. Concentrations of the main PAH metabolites 1-hydroxypyrene, 1-hydroxyphenanthren and 3-hydroxybenzo(a)pyrene were determined in bile by HPLC with fluorescence detection. Fish species under investigation were dab ( Limanda limanda ), flounder ( Platichthys flesus ) and haddock ( Melanogrammus aeglefinus ). A contamination gradient was demonstrated from the low contaminated waters of Iceland and off-shore regions of the North Sea towards higher concentrations in coastal areas. Concentrations of PAH metabolites differed primarily according to sampling region and secondarily to species. [ABSTRACT FROM AUTHOR]

So far, several classes of digesting solutions have been employed to extract microplastics (MPs) from biological matrices. However, the performance of digesting solutions across different temperatures has never been systematically investigated. In the first phase of the present study, we measured the efficiency of different oxidative agents (NaClO or H 2 O 2 ), bases (NaOH or KOH), and acids [HCl or HNO 3 ; concentrated and diluted (5%)] in digesting fish tissues at room temperature (RT, 25 °C), 40, 50, or 60 °C. In the second phase, the treatments that were efficient in digesting the biological materials (> 95%) were evaluated for their compatibility with eight major plastic polymers (assessed through recovery rate, Raman spectroscopy analysis, and morphological changes). Among the tested solutions, NaClO, NaOH, and diluted acids did not result in a satisfactory digestion efficiency at any of the temperatures. The H 2 O 2 treatment at 50 °C efficiently digested the biological materials, although it decreased the recovery rate of nylon-6 (NY6) and nylon-66 (NY66) and altered the colour of polyethylene terephthalate (PET) fragments. Similarly, concentrated HCl and HNO 3 treatments at RT fully digested the fish tissues, but also fully dissolved NY6 and NY66, and reduced the recovery rate of most or all of the polymers, respectively. Potassium hydroxide solution fully eliminated the biological matrices at all temperatures. However, at 50 and 60 °C, it degraded PET, reduced the recovery rate of PET and polyvinyl chloride (PVC), and changed the colour of NY66. According to our results, treating biological materials with a 10% KOH solution and incubating at 40 °C was both time and cost-effective, efficient in digesting biological materials, and had no impact on the integrity of the plastic polymers. Furthermore, coupling this treatment with NaI extraction created a promising protocol to isolate MPs from whole fish samples. [ABSTRACT FROM AUTHOR]

In order to illustrate time difference in toxic effects of cadmium chloride (CdCl 2 ) and deltamethrin (DM), AChE activities were measured in different tissues, liver, muscle, brain, and gill, of Zebra fish ( Danio rerio ) across different concentrations in this research. The average AChE activity decreased comparing to 0.0 TU with DM (82.81% in 0.1 TU, 56.14% in 1.0 TU and 44.68% in 2.0 TU) and with CdCl 2 (74.68% in 0.1 TU, 52.05% in 1.0 TU and 50.14% in 2.0 TU) showed an overall decrease with the increase of exposure concentrations. According to Self-Organizing Map (SOM), the AChE activities were characterized in relation with experimental conditions, showing an inverse relationship with exposure time. As the exposure time was longer, the AChE activities were correspondingly lower. The AChE inhibition showed time delay in sublethal treatments (0.1 TU) in different tissues: the AChE was first inhibited in brain by chemicals followed by gill, muscle and liver (brain > gill > muscle > liver). The AChE activity was almost inhibited synchronously in higher environmental stress (1.0 TU and 2.0 TU). As the AChE inhibition can induce abnormal of behavior movement, these results will be helpful to the mechanism of stepwise behavior responses according to the time difference in different tissues rather than the whole body AChE activity. [ABSTRACT FROM AUTHOR]

This study provided the first hand data of trace elements into fish muscles (N = 65) collected from river Chenab in Pakistan during 2013, using inductively coupled plasma mass spectrometry (ICP-MS). We monitored the health risk associated with consumption of contaminated fish of river Chenab, by the local population. The mean concentrations (μg/g, wet weight), in descending order were: Zn (35.5–54.4), Cu (1.38–4.57), Mn (2.43–4.5), As (0.23–1.21), Cr (0.21–0.67), Ni (0.14–0.34), Pb (0.14–0.31), Co (0.09–0.12), Cd (0.07–0.12) with higher concentration to be observed in the herbivore fish species (i.e., Cirrhinus reba and Catla catla ). The levels of trace elements in different fish species found in this study were compared with similar data worldwide, and with the international standards for consumption. The concentration (μg/g) of arsenic in many cases (>65%) exceeded the FAO/WHO expert committee on food additives permissible limits. From the human health point of view, this study highlights that the local inhabitants, (i.e., fisher folk communities and population frequently consuming fish at about 100 g/day) along the river Chenab are exposed chronically to arsenic pollution with carcinogenic (10 −4 to 10 −6 ) and non-carcinogenic (THQ>1) risks, especially from the intake of Cirrhinus reba . [ABSTRACT FROM AUTHOR]

There is increasing evidence that phenotypic plasticity can promote population divergence by facilitating phenotypic diversification and, eventually, genetic divergence. When a 'plastic' population colonizes a new habitat, it has the possibility to occupy multiple niches by expressing several distinct phenotypes. These initially reflect the population's plastic range but may later become genetically fixed by selection via the process of 'genetic assimilation' ( GA). Through this process multiple specialized sister lineages can arise that share a common plastic ancestor - the 'flexible stem'. Here, we review possible molecular mechanisms through which natural selection could fix an initially plastic trait during GA. These mechanisms could also explain how GA may contribute to cryptic genetic variation that can subsequently be coopted into other phenotypes or traits, but also lead to nonadaptive responses. We outline the predicted patterns of genetic and transcriptional divergence accompanying flexible stem radiations. The analysis of such patterns of (retained) adaptive and nonadaptive plastic responses within and across radiating lineages can inform on the state of ongoing GA. We conclude that, depending on the stability of the environment, the molecular architecture underlying plastic traits can facilitate diversification, followed by fixation and consolidation of an adaptive phenotype and degeneration of nonadaptive ones. Additionally, the process of GA may increase the cryptic genetic variation of populations, which on one hand may serve as substrate for evolution, but on another may be responsible for nonadaptive responses that consolidate local allopatry and thus reproductive isolation. [ABSTRACT FROM AUTHOR]

Currently, the term syndrome M74 combines all reproductive disorders of hydrobionts (including their gametes, embryos and yolk-sac fry) with similar symptoms caused by xenobiotics transposed in aquatic organisms from polluted environment. Because in Bulgaria there are only few publications on the M74 and the syndrome is not known to fish farmers in the branch, the aim of the present study was to analyze the reproductive process in Bulgarian trout farms, located in different mountains regions and make recommendations for preventing M74 syndrome. This is why for the first time in the country were developed criteria for assessing the risk of syndrome M74 and questions were formulated in a special „Questionnaire". The survey data from 14 Bulgarian trout farms were calculated to analyze the reproductive process and investigate the possibility for spreading of the syndrome M74 mainly on farms located in the following mountains: Rila, Rhodope, Stara Planina and Sredna Gora. Additionally were investigated commonly used biological parameters for assessment of the reproductive syndrome M74 - eggs fertilization, hatchability and survival rate of the rainbow trout fry. Better reproductive parameters were registered in 1st rank trout farms (0-5 points) which have no problems with the M74 syndrome. In the rest farms the unsuitable environmental conditions, which lead to occur M74 syndrome can be partly compensated using a sperm activation medium №49397 for artificial insemination of trout eggs. [ABSTRACT FROM AUTHOR]

Tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) is a re-emerging environmental contaminant that has been frequently detected at sub-ppb (<μg/L) concentrations in natural waters. The objective of this study was to evaluate effects of TDCIPP on growth in initial generation (F 0 ) zebrafish after chronic exposure to environmentally relevant concentrations, and to examine possible parental transfer of TDCIPP and transgenerational effects on growth of first generation (F 1 ) larvae. When zebrafish (1-month old) were exposed to 580 or 7500 ng TDCIPP/L for 240 days, bioconcentration resulted in significantly less growth as measured by body length, body mass, brain-somatic index (BSI) and hepatic-somatic index (HSI) in F 0 females but not F 0 males. These effects were possibly due to down-regulation of expression of genes along the growth hormone/insulin-like growth factor (GH/IGF) axis. Furthermore, residues of TDCIPP were detected in F 1 eggs after exposure of parents, which resulted in less survival, body length and heart rate in F 1 individuals. Down-regulation of genes in the GH/IGF axis (e.g., gh , igf1 ) might be responsible for transgenerational toxicity. This study provides the first known evidence that exposure of zebrafish to environmentally relevant concentrations of TDCIPP during development can inhibit growth of offspring, which were not exposed directly to TDCIPP. [ABSTRACT FROM AUTHOR]

This work addresses human stressors and their impacts on fish assemblages at pan-European scale by analysing single and multiple stressors and their interactions. Based on an extensive dataset with 3105 fish sampling sites, patterns of stressors, their combination and nature of interactions, i.e. synergistic, antagonistic and additive were investigated. Geographical distribution and patterns of seven human stressor variables, belonging to four stressor groups (hydrological-, morphological-, water quality- and connectivity stressors), were examined, considering both single and multiple stressor combinations. To quantify the stressors' ecological impact, a set of 22 fish metrics for various fish assemblage types (headwaters, medium gradient rivers, lowland rivers and Mediterranean streams) was analysed by comparing their observed and expected response to different stressors, both acting individually and in combination. Overall, investigated fish sampling sites are affected by 15 different stressor combinations, including 4 stressors acting individually and 11 combinations of two or more stressors; up to 4 stressor groups per fish sampling site occur. Stressor-response analysis shows divergent results among different stressor categories, even though a general trend of decreasing ecological integrity with increasing stressor quantity can be observed. Fish metrics based on density of species ‘intolerant to water quality degradation’ and ‘intolerant to oxygen depletion” responded best to single and multiple stressors and their interactions. Interactions of stressors were additive (40%), synergistic (30%) or antagonistic (30%), emphasizing the importance to consider interactions in multi-stressor analyses. While antagonistic effects are only observed in headwaters and medium-gradient rivers, synergistic effects increase from headwaters over medium gradient rivers and Mediterranean streams to large lowland rivers. The knowledge gained in this work provides a basis for advanced investigations in European river basins and helps prioritizing further restoration and management actions. [ABSTRACT FROM AUTHOR]

Environmental pollution is a serious problem of the modern world that possesses a major threat to public health. Exposure to environmental pollutants during embryonic development is particularly risky. Although many pollutants have been verified as potential toxicants, there are new chemicals in the environment that need assessment. Heart development is an extremely sensitive process, which can be affected by environmentally toxic molecule exposure during embryonic development. Congenital heart defects are the most common life-threatening global health problems, and the etiology is mostly unknown. The zebrafish has emerged as an invaluable model to examine substance toxicity on vertebrate development, particularly on cardiac development. The zebrafish offers numerous advantages for toxicology research not found in other model systems. Many laboratories have used the zebrafish to study the effects of widespread chemicals in the environment on heart development, including pesticides, nanoparticles, and various organic pollutants. Here, we review the uses of the zebrafish in examining effects of exposure to external molecules during embryonic development in causing cardiac defects, including chemicals ubiquitous in the environment and illicit drugs. Known or potential mechanisms of toxicity and how zebrafish research can be used to provide mechanistic understanding of cardiac defects are discussed. [ABSTRACT FROM AUTHOR]

Acute aquatic toxicity is divided into the 'physical' mode governed by weak, non-covalent interactions and the 'chemical' mode governed by covalent reactions. The potency of chemical interactions is typically expected to be greater than that for physical ones. This enhanced potency is called 'excess' toxicity. As databases have become complex, substances thought to elicit a chemical mode reveal a lack of excess toxicity. One mechanism where the latter is prevalent is Michael-type addition. A series of α-β-unsaturated substances were evaluated for reactivity. Second order rate constants ( k′) were calculated (M s) and found to vary from >4000 to <0.0003. The electron-withdrawing capacity of the polar group impacts k′ values; the sequence is nitro > carbonyl or sulfone ≫ sulfoxide, nitrile or amide. When the α-carbon and/or the β-carbon of the π-system are substituted, the k′ value is sharply reduced. Excess toxicity is associated with k′ values >0.01 (M s). [ABSTRACT FROM AUTHOR]

Aquatic ecosystems are subjected to a variety of man-induced stressors but also vary spatially and temporally due to variation in natural factors. In such complex environments, it remains difficult to detect, dissociate and evaluate the effects of contaminants in wild organisms. In this context, the aim of this study was to test whether the hepatic transcriptome profile of fish may be used to detect in situ exposure to a particular contaminant. Transcriptomic profiles from laboratory-exposed and wild eels sampled along a contamination gradient were compared. During laboratory experiments, fish were exposed during 45 days to different pollutants (Hg, PCBs, OCPs or Cd) or natural factors (temperature, salinity or low food supply) at levels close to those found in the sampling sites. A strong difference was observed between the transcriptomic profiles obtained from wild and laboratory-exposed animals (whatever the sites or experimental conditions), suggesting a general stress induced by captivity in the laboratory. Among the biological functions that were up-regulated in laboratory eels in comparison to wild eels, histone modification was the most represented. This finding suggests that laboratory conditions could affect the epigenome of fish and thus modulate the transcriptional responses developed by fish in response to pollutant exposure. Among experimental conditions, only the transcription profiles of laboratory animals exposed to cold temperature were correlated with those obtained from wild fish, and more significantly with fish from contaminated sites. Common regulated genes were mainly involved in cell differentiation and liver development, suggesting that stem/progenitor liver cells could be involved in the adaptive response developed by fish chronically exposed to pollutant mixtures. [ABSTRACT FROM AUTHOR]

Species sensitivity distributions (SSDs) are commonly used in regulatory procedures and ecological risk assessments. Yet, most toxicity threshold and risk assessment studies are based on invertebrates and fish. In the present study, no observed effect concentrations (NOECs) specific to birds and mammals were used to derive SSDs and corresponding hazardous concentrations for 5% of the species (HC5 values). This was done for 41 individual substances as well as for subsets of substances aggregated based on their toxic Mode of Action (MoA). In addition, potential differences in SSD parameters (mean and standard deviation) were investigated in relation to MoA and end point (growth, reproduction, and survival). The means of neurotoxic and respirotoxic compounds were significantly lower than those of narcotics, whereas no differences were found between end points. The standard deviations of the SSDs were similar across MoA's and end points. Finally, the SSDs obtained were used in a case study by calculating Ecological Risks (ER) and multisubstance Potentially Affected Fractions of species (msPAF) based on 19 chemicals in 10 Northwestern European estuaries and coastal areas. The assessment showed that the risks were all below 2.6 ? 10-2. However, the calculated risks underestimate the actual risks of chemicals in these areas because the potential impacts of substances that were not measured in the field or for which no SSD was available were not included in the risk assessment. The SSDs obtained can be used in regulatory procedures and for assessing the impacts of contaminants on birds and mammals from fish contaminants monitoring programs. [ABSTRACT FROM AUTHOR]

The removal process of 2,2-dichloroacetamide (DCAcAm), a new disinfection by-product (DBP) in conventional drinking water treatment plant (C-DWTP) and advanced DWTP (ADWTP) was studied with newly maximum formation potential (MFP) process. It was demonstrated that the advanced treatment displayed greater removal efficiency towards DCAcAm formation potential (MFP) than the conventional treatment. The hydrophilic natural organic matter and natural organic matter with molecular weight <1 kDa or >10 kDa leaded to more DCAcAm formation, and the aromatic protein was inferred as one part of DCAcAm precursor. DCAcAm was found to cause delayed development and malformation to zebrafish embryos at embryonic growth stage. Compared with heart toxicity, it caused a significant neuron toxicity. It also could cause the acute DNA damage to adult zebrafish, which should be extremely cautioned. [ABSTRACT FROM AUTHOR]

A comparison of whole-fish polychlorinated biphenyl (PCB) and total mercury (Hg) concentrations in mature males with those in mature females may provide insights into sex differences in behavior, metabolism, and other physiological processes. In eight species of fish, we observed that males exceeded females in whole-fish PCB concentration by 17 to 43%. Based on results from hypothesis testing, we concluded that these sex differences were most likely primarily driven by a higher rate of energy expenditure, stemming from higher resting metabolic rate (or standard metabolic rate (SMR)) and higher swimming activity, in males compared with females. A higher rate of energy expenditure led to a higher rate of food consumption, which, in turn, resulted in a higher rate of PCB accumulation. For two fish species, the growth dilution effect also made a substantial contribution to the sex difference in PCB concentrations, although the higher energy expenditure rate for males was still the primary driver. Hg concentration data were available for five of the eight species. For four of these five species, the ratio of PCB concentration in males to PCB concentration in females was substantially greater than the ratio of Hg concentration in males to Hg concentration in females. In sea lamprey (Petromyzon marinus), a very primitive fish, the two ratios were nearly identical. The most plausible explanation for this pattern was that certain androgens, such as testosterone and 11-ketotestosterone, enhanced Hg-elimination rate in males. In contrast, long-term elimination of PCBs is negligible for both sexes. According to this explanation, males not only ingest Hg at a higher rate than females but also eliminate Hg at a higher rate than females, in fish species other than sea lamprey. Male sea lamprey do not possess either of the above-specified androgens. These apparent sex differences in SMRs, activities, and Hg-elimination rates in teleost fishes may also apply, to some degree, to higher vertebrates including humans. Our synthesis findings will be useful in (1) developing sex-specific bioenergetics models for fish, (2) developing sex-specific risk assessment models for exposure of humans and wildlife to contaminants, and (3) refining Hg mass balance models for fish and higher vertebrates. [ABSTRACT FROM AUTHOR]

This study investigated toxic effects in mosquitofish from two urban rivers of South China impacted by municipal effluents by using multiple biomarkers including fish morphology, biochemical indicators and transcriptional responses, and explored potential cause-effect relationship with a list of chemicals (metals, polycyclic aromatic hydrocarbons (PAHs) and pesticides). The results showed significant alterations in metallothionein (MT) protein and mRNA expression in mosquitofish collected from the two rivers and a strong association between MT protein and mRNA expression levels and heavy metals in the river water. Both ethoxyresorufin- O -deethylase (EROD) activity and cytochromes P450 1A (CYP1A) mRNA expression were significantly enhanced in mosquitofish at most sampling sites. There existed a strong correlation between EROD activity and CYP1A mRNA expression levels, but no clear correlations between these responses and PAHs in the river water possibly because of the presence of many other agonists of the aryl hydrocarbon receptor in the two rivers. Significant acetylcholinesterase (AChE) inhibition was observed in mosquitofish brain samples. The pesticides in the two rivers showed an influence on the AChE activity, which was also found to be significantly negatively correlated to fipronil concentrations. Moreover, the result also indicates that metals and pesticides present in the two rivers might cause the observed estrogenic and androgenic effects in mosquitofish. The findings from this study clearly showed morphological, biochemical and transcriptional responses in mosquitofish due to chemical contamination of the two urban rivers. This multi-biomarker approach using mosquitofish can be applied to evaluate contamination of riverine environments. [ABSTRACT FROM AUTHOR]

The present study contemplates the enzymatic profile of grass carp, including lactate dehydrogenase (LDH), creatinine phosphokinases (CPK), serum glutamic-pyruvic transaminase (SGPT), and alkaline phosphatase (Alk Phosp) under atrazine's acute toxicity effects (LC50) for 01 (15 μl/L), 02 (13 μl/L), 03 (10 μl/L), and 04 (08 μl/L) days/concentration, respectively. For analyzing the enzymatic profile we followed the biochemical analyzer set protocol (Merck micro lab 300 biochemistry analyzer) in the laboratory. Control group concentrations for LDH, CPK, SGPT, and Alk Phosp were 342 IU/ml, 7513.3 IU/ml, 46 mmol/l, and 126.6 IU/ml, respectively. After treatment LDH concentrations were 906, 851, 765, and 545 IU/ml, respectively. CPK concentrations were 1,737, 2,445, 3,718, and 5,767 IU/ml, respectively. SGPT concentrations were 27, 24.3, 13.67, and 8.67, respectively, and Alk Phosp concentrations were 50.3, 30, 22.3, and 17.6 IU/ml, respectively. Maximum inclined (P≤0.001) in concentration of LDH was observed after 24 hrs exposure because of hepatic tissue damage, resulting in increased membrane permeability causing enhanced leaching out of LDH and as LDH participates in an anaerobic pathway, so increase LDH mean increases of anaerobic metabolism resulting from depletion of energy under environmental stress conditions by atrazine, while other enzymatic components like CPK, SGPT, and Alk Phosp showed kindred attributes in their result, like all parameter concentrations showed perpetual decline (P=0.001) in their concentrations indicating reduced enzymatic activity due to a reduction in permeability for these enzymes, forcing the enzymes to accumulate in the cells as well as decrease in enzyme synthesis due to intoxication of atrazine. [ABSTRACT FROM AUTHOR]

The effect of the quality of two microalgal species on select biological and biochemical responses used as indicators of pollution were assessed. Mussels were conditioned for 6 weeks with the diatom Chaetoceros neogracile and the dinoflagellate Heterocapsa triquetra , chosen for being two clearly different types of primary production quality that differ in both biometric and biochemical characteristics. After dietary conditioning, the mussels were exposed to a polycyclic aromatic hydrocarbon, fluoranthene (FLU), for 1 week followed by 1 week of depuration. Results showed higher FLU accumulation in mussels fed on C. neogracile compared to those fed on H. triquetra . Concomitantly, a greater impact of this toxicant was observed in the biomarker responses of mussels fed on C. neogracile . These mussels showed an increase in the percentage of dead hemocytes, an activation of phagocytosis and ROS production of hemocytes after exposure. Some enzymatic activities also increased upon FLU exposure (superoxide dismutase −SOD-, catalase −CAT-, and glutathione reductases −GR-) and after depuration (glutathione-s-transferase −GST-). Results suggest that FLU exposure as well as food quality influence biomarker responses, with higher values of SOD, CAT and GR in non-exposed mussels fed on C. neogracile . In addition, upon exposure to the same FLU concentration, GR response varied according to dietary conditioning, suggesting that diet could act as a confounding factor in biomarker responses to pollution. Consequently, trophic conditions should be considered in marine pollution monitoring programs for a better interpretation of biomarker responses. [ABSTRACT FROM AUTHOR]

The low concentrations of most contaminants in the aquatic environment individually may not affect the normal function of the organisms on their own. However, when combined, complex mixtures may provoke unexpected effects even at low amounts. Selected aquatic micropollutants such as chlorpyrifos, bis-(2-ethylhexyl)-phthalate (DEHP), perfluorooctanoic acid (PFOA) and 17α-ethinylestradiol (EE2) were tested singly and in mixtures at nM to μM concentrations using precision-cut liver slices (PCLS) of Atlantic cod ( Gadus morhua ). Fish liver is a target organ for contaminants due to its crucial role in detoxification processes. In order to understand the effects on distinct key liver metabolic pathways, transcription levels of various genes were measured, including cyp1a1 and cyp3a, involved in the metabolism of organic compounds, including toxic ones, and the catabolism of bile acids and steroid hormones; cyp7a1, fabp and hmg-CoA, involved in lipid and cholesterol homeostasis; cyp24a1, involved in vitamin D metabolism ; and vtg, a key gene in xenoestrogenic response. Only EE2 had significant effects on gene expression in cod liver slices when exposed singly at the concentrations tested. However, when exposed in combinations, effects not detected in single exposure conditions arose, suggesting complex interactions between studied pollutants that could not be predicted from the results of individual exposure scenarios. Thus, the present work highlights the importance of assessing mixtures when describing the toxic effects of micropollutants to fish liver metabolism. [ABSTRACT FROM AUTHOR]

The developing fish heart is vulnerable to a diverse array of toxic chemical contaminants in freshwater, estuarine, and marine habitats. Globally occurring examples of cardiotoxic agents include dioxins, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). The disruption of cardiac function during the process of heart morphogenesis can lead to adverse outcome pathways (AOPs) that can negatively affect fish survival at hatching as well as later life stages. Proximal impacts include cardiogenic fluid accumulation (edema) and defects of the body axis and jaw that preclude larval feeding. More subtle changes in heart development can produce permanent structural defects in the heart that reduce cardiac output and swimming performance in older fish. In recent decades, the presence of edema in fish embryos and larvae has been a very common bioindicator of cardiotoxicity. However, the different ways that edema forms in fish from different habitats (i.e., freshwater vs. marine, pelagic vs. demersal) has not been rigorously examined. Oil spills are an important source of PAHs in fish spawning areas worldwide, and research is revealing how patterns of cardiogenic edema are shaped by species-specific differences in developmental anatomy and ionoregulatory physiology. Here we review the visible evidence for circulatory disruption across nine freshwater and marine fish species, exposed to crude oils from different parts of the world. We focus on the close interconnectedness of the cardiovascular and osmoregulatory systems during early development, and corresponding implications for fish in hyperosmotic and hyposmotic habitats. Finally, we suggest there may be poorly understood adverse outcomes pathways related to osmotic gradients and water movement within embryos, the latter causing extreme shifts in tissue osmolality. [ABSTRACT FROM AUTHOR]

Biomarkers are useful tools to assess biological effects of pollutants and have been extensively used in monitoring programs to determine ecosystem health. In these programs, a wide range of environmental conditions are covered and sometimes, obtained data are difficult to interpret because of natural variables are affecting biomarker responses. Among these variables, musseĺs reproductive status has been considered one of the most changing variables between sites in a monitoring survey. Thus, the main aim of this work was to identify the effect that mussel reproductive status has on biomarker responses. For that purpose, mussels sampled at two periods in the reproductive cycle (reproductive and resting stages) were conditioned to the same laboratory conditions and exposed to fluoranthene (FLU) for three weeks. Studied biomarkers covering a wide range of organism responses were included: bioaccumulation, physiological rates (clearance rate −CR-, absorption efficiency −AE-, respiration rate −RR- and their integration in the scope for growth −SFG-), antioxidant enzyme activities (superoxide-dismutase −SOD-, catalase −CAT-, glutathione reductase −GR-, glutathione peroxidase −GPx-, glutathione-S-tranferase −GST-) and biochemical damage responses (lipid membrane peroxidation −LPO-). The results obtained evidenced that the levels of the biomarkers studied (RR, SOD, CAT and GPx) were higher at reproductive than at resting stage. On the other hand, the effect of toxicant was observed in SFG, CAT and GPx but this effect was only detected during the resting period. Moreover, there was a deterioration of mussel gonadal tissue with FLU exposure during reproductive stage. FLU accumulation in mussel tissues was also dependent of the reproductive status with higher internal concentrations during resting than reproductive period. In conclusion, there was a strong effect of reproductive status on studied biomarkers which seems to mask the effect of FLU at reproductive stage. The present study evidences the need to include the measurement of mussel biological status in marine pollution monitoring programs for a correct interpretation of biomarker data. [ABSTRACT FROM AUTHOR]

Populations can adapt to stress including recent anthropogenic pollution. Our published data suggests heritable differences in hepatocyte oxidative phosphorylation (OxPhos) metabolism in field-caught killifish ( Fundulus heteroclitus) from the highly polluted Elizabeth River, VA, USA, relative to fish from a nearby, relatively unpolluted reference site in King’s Creek VA. Consistent with other studies showing that Elizabeth River killifish are resistant to some of the toxic effects of certain contaminants, OxPhos measurements in hepatocytes from field-caught King’s Creek but not field-caught Elizabeth River killifish were altered by acute benzo [a] pyrene exposures. To more definitively test whether the enhanced OxPhos metabolism and toxicity resistance are heritable, we measured OxPhos metabolism in a laboratory-reared F3 generation from the Elizabeth River population versus a laboratory-reared F1 generation from the King’s Creek population and compared these results to previous data from the field-caught fish. The F3 Elizabeth River fish compared to F1 King’s Creek fish had significantly higher State 3 respiration (routine metabolism) and complex II activity, and significantly lower complex I activity. The consistently higher routine metabolism in the F3 and field-caught Elizabeth River fish versus F1 and field-caught King’s Creek fish implies a heritable change in OxPhos function. The observation that LEAK, E-State, Complex I and Complex II were different in laboratory bred versus field-caught fish suggests that different physiological mechanisms produce the enhanced OxPhos differences. Finally, similar to field-caught Elizabeth River fish, acute benzo [a] pyrene exposure did not affect OxPhos function of the laboratory-reared F3 generation, supporting the heritability of the toxicity resistance. Overall, these results suggest that the Elizabeth River population has evolved genetic changes in physiological homeostasis that enhance routine metabolism, and we speculate that these genetic changes interact with environmental factors altering the physiological mechanisms ( e.g., alter LEAK, Complex I, and electron transfer system capacity) used to achieve this enhanced metabolism. [ABSTRACT FROM AUTHOR]

This study sought to analyze structures of lymphatic tissues in two commercial fish species, e.g. Sole (Euryglossa orientalis) and Yellowfin Seabream (Acanthopagus latus), collected from five stations with varying levels of pollution in the Musa Creek near the Persian Gulf, e.g. Petro-chemical, Gaafari, Majidieh, Ghazaleh and Zangi Stations. Samples from Genaveh Station located outside Musa Creek were collected as controls. To correlate findings of changes in the studied tissues with local pollution status, levels of Hg, Pb, Zn, Cu and Cd were measured in sediments and water at each station. Fish were caught from the sampling stations; the spleen and head kidney were collected and sections prepared to permit histologic evaluation. The results indicated that, in both species, the most common changes were observed in fish collected near the Petrochemical station and included an increase in melano-macrophage aggregates, hemorrhage and damaged/dead red blood cells in the spleen; in the head kidney, the major findings were melano-macrophage aggregation, hemorrhage and lifting of the tubular basement membrane. No pathological alternations were noted in the spleen and head kidney of fish from the Zangi station. Samples ofA. latuscollected from Gaafari station and ofE. orientalisfrom Majidieh station also had pathological changes. No significant differences were found in the tissue structures of fish recovered from the Zangi and Genaveh control stations. The concentrations for nearly all of the studied metals in sediment and water samples collected from the different stations followed the pattern: Petrochemical station ≈ Majidieh ≈ Gaafari >> Ghazaleh > Zangi Stations. From the data, it was concluded that changes in lymphoid tissues of the fish studied here “correlated” with geographical conditions and sources of pollution at the different test stations. What these changes mean to the long-term health of both species remains to be determined in ongoing studies. [ABSTRACT FROM PUBLISHER]

PCBs were analyzed in two species of oyster ( Crassostrea gigas and Ostrea edulis) cultured in intertidal beds and rafts coming from the Galician Rías during the period 2011-2014. PCBs were also analyzed in mussel ( Mytilus galloprovincialis) collected in the same Rías during 2011. The main objective of this work is to investigate the distribution of PCBs in Galician oysters and to study their suitability as bioindicator in comparison to mussels. The levels of ΣPCBs (ten congeners) ranged from 5.58 to 179.49 ng g d.w. The effect of biological parameters (shell length, lipid content and condition index) on bioaccumulation of PCBs was also evaluated. ANOVA showed a statistically significant difference between species for higher chlorinated biphenyls (CBs 153 and 138). The spatial patterns were investigated. Principal Component Analysis (PCA) showed differences between geographical areas (Rías Altas, Centrales and Baixas) in the distribution of PCBs. [ABSTRACT FROM AUTHOR]