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Pendimethalin, an herbicide active substance frequently used in terrestrial systems, has detected in European aquatic ecosystems. Reliable indicators still need to be found in order to properly assess the impact of pesticides in fish. After an in vivo chronic exposure to pendimethalin, the detoxification process and the antioxidant defense system were assessed in 120 adult rainbow trout, Oncorhynchus mykiss. Four nominal exposure conditions were tested: control (C), 500ngL−1 (P500), 800ngL−1 (P800) and the commercial formulation Prowl® at 500ngL−1 (Pw500). Fish samples were made after a 28 day exposure period (D28) and after a fifteen day recovery period in clean fresh water (D43). At D28, ethoxyresorufin-O-deethylase (EROD) activity was not activated in liver in spite of the pendimethalin uptake in fish. At D43, EROD activity in fish exposed to the commercial product was lower than in control fish, which may be explained by the high presence of herbicide in fish (613±163ngg bile−1). Furthermore, antioxidant defense responses were set up by trout in gills and liver following chronic exposure to 800ngL−1 of pendimethalin concentration. While the glutathione content (GSH) decreased in gills, it increased in liver associated with higher activities of glutathione peroxidase (GPx) and superoxide dismutase (SOD). These disturbances could lead to reactive oxygen species production and oxidative stress in the vital organs in fish. After fifteen days in clean water, while the SOD activity was restored, the GSH content and GPx activity were still significantly disturbed in fish exposed to pendimethalin in comparison with control. These significant differences between treatments in antioxidant defenses parameters measured, attesting to the irreversibility of the effects. [Copyright &y& Elsevier]

Abstract: The strobilurins are used widely in the world as effective fungicidal agents to control Asian soybean rust. In this study, the early life stage of grass carp (Ctenopharyngodon idella), which is one of the most important aquaculture species in China, was chosen to measure the acute toxicity of three common strobilurin-derived fungicides (trifloxystrobin (TFS), azoxystrobin (AZ) and kresoxim-methyl (KM)). As endpoints, normal developmental parameters (lethal concentration (LC 50) and average heart rate), expression of relative genes, and three antioxidant enzyme activities in the developing juveniles were recorded during a 48h exposure. The results revealed that values of LC 50 were TFS 0.051 (0.046–0.058) mgL−1, AZ 0.549 (0.419–0.771) mgL−1 and KM 0.338 (0.284–0.407) mgL−1 for juveniles. For the potential toxicity mechanisms, these three fungicides increased catalase (CAT) and peroxidase (POD) activity and decreased superoxide dismutase (SOD) activity, significantly inhibited expressions of three growth-related genes (IGF-1, IGF-2 and GHR) and two energy-related-genes (CCK and PYY), and caused pronounced up-regulation a stress-gene (HSP70). The present study demonstrated potential toxic effects of TFS, AZ and KM on the early development of C. idella. Overall, three strobilurins (TFS, AZ and KM) might cause serious damages to the aquatic species; therefore, their pollution supervision in water ecological environment should be strengthened. [Copyright &y& Elsevier]

Abstract: Because contaminants and nutrients always coexist in fish, the risk from contaminants and the benefit from nutrients, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are also concomitant via fish consumption. To investigate the risk and benefit via fish consumption, concentrations of dichlorodiphenyltrichloroethane and its metabolites (DDTs), and hexachlorocyclohexanes (HCHs) in the whole- and portion-muscles of fish from Taihu Lake, China, were measured. Based on the contaminant data and nutrients from our previous study, and the associated risk and benefit via fish consumption were estimated. The concentrations of DDTs and HCHs in the whole-muscles ranged from 7.8×102 to 3.4×103 pgg−1 ww, and from 67.3 to 300pgg−1 ww, respectively. Of DDTs and HCHs measured, p,p′-DDE and β-HCH were respectively the most abundant pesticides. The composition profiles of DDTs and HCHs suggested that the pesticides were mainly historical residues. The benefit–risk quotient (BRQ) of EPA+DHA vs. POPs (persistent organic pollutants including data of DDTs, HCHs, and those of polychlorinated biphenyls and polybrominated diphenyl ethers cited from our previous study) via consumption of fish from Taihu Lake was calculated. As a result, to achieve the recommended EPA+DHA intake of 250mgd−1 for a healthy adult, the consumption of most fish species from the lake can cause cancer and non-cancer risks. However, the fish consumption at the rates of 44.9gd−1 by Chinese would not lead to the risks for most of the species. The results also suggested that the risk of consuming silver carp was generally lower than other fish species, and those of dorsal muscles were lower than ventral and tail muscles. [Copyright &y& Elsevier]

Abstract: The ability of two 48 percent chlorpyrifos-based insecticides (Lorsban* 48E® and CPF Zamba®), two 50 percent pirimicarb-based insecticides (Aficida® and Patton Flow®), and two 48 percent glyphosate-based herbicides (Panzer® and Credit®) to induce DNA single-strand breaks in peripheral blood erythrocytes of Cnesterodon decemmaculatus (Jenyns, 1842) (Pisces, Poeciliidae) exposed under laboratory conditions was evaluated by the single-cell gel electrophoresis (SCGE) assay. In those fish exposed to Lorsban* 48E®, CPF Zamba®, Aficida®, Patton Flow®, Credit®, and Panzer®, a significant increase of the genetic damage was observed for all formulations regardless of the harvesting time. This genotoxic effect was achieved by an enhancement of Type II-IV comets and a concomitant decrease of Type 0-I comets over control values. A regression analysis revealed that the damage varied as a negative function of the exposure time in those Lorsban* 48E®- and Aficida®-treated fish. On the other hand, a positive correlation between damage increase and exposure time was achieved after Patton Flow® and Credit® treatment. Finally, no correlation was observed between increase in the genetic damage and exposure time after treatment with CPF Zamba® or Panzer®. These results highlight that all agrochemicals inflict primary genotoxic damage at the DNA level at sublethal concentrations, regardless of the exposure time of the aquatic organisms under study, at least within a period of 96h of treatment. [Copyright &y& Elsevier]

The present study is the first report on optimization of recovery conditions of fishes exposed to pesticides using response surface methodology-central composite rotatable design (RSM-CCRD). The sub-lethal toxicity bioassay of Roundup® (2ppm ~10 percent LC50, 96h) in common carp (1, 4, 9, 16, 25, 35 and 40 day) was investigated. After exposure for 16 days to Roundup®, some the fishes were introduced to herbicide-free water. The effects of four recovery parameters including time (5–25d), temperature (18–26°C), water exchange rate (WER, 10–30), and salinity (0–8ppt) on the levels of biomarkers of genotoxicity (DNA damage), neurotoxicity (acetylcholinesterase activity (AChE)), and the serum alanine (ALT) and aspartate (AST) aminotransferase in plasma were studied. The polynomial equations were significantly fitted for all response variables with high R 2 values (>0.95), which revealed no indication of lack of fit. The optimum conditions for the maximum AChE activity (37.14nmol/min/mg protein) and the minimum levels of DNA damage (8.00 percent tail DNA), ALT (27.0IU/L) and AST (91.0IU/L) were time of 20d, temperature of 20°C, WER of 25 and water salinity of 6ppt. Thus, a promising improvement for the recovery trend of fishes exposed to Roundup® stress was obtained under the optimized conditions using RSM-CCRD. [Copyright &y& Elsevier]

The objective of this study was to investigate the toxicity effects of acute and sublethal of Roundup® as a glyphosate-based herbicide on acetylcholinesterase (AChE) activity and several hematological and biochemical parameters of Cyprinus carpio. The LC50-96h of Roundup® to C. carpio was found to be 22.19ppm. Common carp was subjected to Roundup® at 0 (control), 3.5, 7 and 14ppm for 16 days, and the AChE activity is verified in tissues of gill, muscle, brain and liver. After 5 days, a significant decrease was observed in the AChE activity of muscle, brain and liver tissues. Besides, a time- and dose-dependent increase in mean cell hemoglobin (MCH) and mean cell volume (MCV) was observed. In contrast, a significant decrease was found in the quantities of hemoglobin (Hb), hematocrit (HCT) and, red (RBC) and white (WBC) blood cell count. Also, the activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) in Roundup® treated groups were significantly higher than the controlled group at experimental periods. However, the level of alkaline phosphatase (ALP) had a significant reduction behavior during the sampling days. It seems that the changes in hematological and biochemical parameters as well as AChE activity could be used as efficient biomarkers in order to determine Roundup® toxicity in aquatic environment. [Copyright &y& Elsevier]

Tissue distribution and bioaccumulation of organochlorine pesticides (OCPs) in edible fishes collected from Taihu Lake, Cyprinus carpio ( C. carpio) and Ctenopharyngodon idellus ( C. idellus), were studied. OCPs were detected in all samples with hexachlorocyclohexanes (HCHs), aldrins (including aldrin, dieldrin, endrin, endrin aldehyde, and endrin ketone), heptachlors (heptachlor and heptachlor epoxide) and dichlorodiphenyltrichloroethanes (DDTs) being the predominant compounds for both fish species. Gill and gonad were found to be the dominant tissues for OCP bioaccumulation followed by liver, while muscle showed the least affinity of OCPs for both fishes. Tissue distribution indicated the exchange of contaminants between water and gill, as well as the food intake from environment were the dominant pathways for OCP bioaccumulation in gill-breathing fish, and the following tissue distribution was affected by both the physiological properties of target tissues and physicochemical characteristics of pesticides. OCP residues in fish were species-specific (45.63-1575.26 ng/g dry weight (dw) for C. idellus; 8.40-60.23 ng/g dw for C. carpio) mainly due to the growth rate of individuals as well as the metabolic capacity difference among species. HCHs and DDTs observed in fishes from Taihu Lake were comparable and moderate with other reported places in China. Human exposure risk assessment performed with the estimated daily intake values demonstrated the consumption of target fish species in Taihu Lake at present was safe. [ABSTRACT FROM AUTHOR]

Diazinon is a commonly used pesticide and its existence in the fresh water reservoirs of Pakistan has been reported by some authors. A semistatic experiment was conducted to find out the acute toxicity of diazinon as an aquatic pollutant on some hematological parameters of Indian carp (Cirrhinus mrigala). The 1, 24, 48, 72, and 96 h LC50 values of diazinon for Indian carp were estimated as 17.32 mg/L, 15.39 mg/L, 12.64 mg/L, 10.98 mg/L, and 8.15 mg/L respectively. A significant increase in the number of dead fish was observed as the concentration of diazinon and exposure time increased (P < 0.05). The results after acute exposure to 8.15 mg/L of diazinon for 96 h showed that compared to the control fish, the total erythrocytes, leukocytes, hemoglobin, and hematocrit values decreased significantly (P < 0.05) in exposed fish. The mean corpuscular volume and mean corpuscular hemoglobin increased significantly (P < 0.05), while the mean corpuscular hemoglobin concentration of both groups remained unchanged during the study. In conclusion, acute exposure to LC50 values of diazinon induced hematological alterations in Indian carp and offers a tool to evaluate toxicity derived alterations. [ABSTRACT FROM AUTHOR]

The aim of this study was to estimate the residue of chlorinated pesticides in the edible fish caught in the Gulf of Gdańsk and in the Vistula Lagoon. The highest mean concentrations of total DDT were found in the muscles of salmon (331.45 ng g lw.) and sabre carp (306.29 ng g lw.) caught in the Vistula Lagoon, and in the muscles of cod (309.88 ng g lw.) and herring (304.86 ng g lw.) from the Gulf of Gdańsk. Moreover, it was discovered that the following were present in the muscles of fish: DDT metabolites (pp'-DDE and pp'-DDD isomers) as well as hexachlorobenzene and its metabolites and endrin, dieldrin, α-endosulfan isomers and methoxychlor. Pesticides concentrations were higher in the livers of fish than in the muscles, which proves that the removal of toxins from the fish systems dominates over their accumulation. Because no concentration limits for pesticides have been defined, consumer safety assessment of fish caught in the Southern Baltic and in the Vistula Lagoon is not possible. The authors, having observed an increase in heksachlorobenzen in fish tissues suggested the existence of contemporary sources of pesticides which introduce them into the coastal zone. [ABSTRACT FROM AUTHOR]

To determine possible human and environmental health risks, organochlorine pesticide residues were determined in vegetables grown in floodplains along the Ouémé River near Lowé in Bénin. Testing of vegetables found 13 pesticides with ΣDDT, α-endosulfan, Σdrin, and lindane being most important. The same pesticides were also detected in plants eaten by bovine cattle, sheep, and herbivorous fish. Human pesticide intake by vegetable consumption was compared with tolerable daily intake (TDI) values reported by the World Health Organization. Pesticide intake by fish consumption was estimated from residue levels in whole fish collected from the Ouémé River in 2004 and reported earlier. Fish consumption does not pose a risk for human health, but consuming vegetables that contain pesticide residues may lead to exceedance of TDI values. Based on these findings, concerns are warranted, and more work is needed to understand the full exposure profile for the local population. [ABSTRACT FROM AUTHOR]

This work investigates the changes in the morphological traits, body composition, body fat and oxidative stress of Sparus aurata under two stress conditions: a low weekly exposure to the pesticide Diuron and chronic handling stress. The fish exposed to handling stress showed lower values in the morphological traits and perivisceral fat, whereas chemical stress induced a decrease in the percentage of muscle and carcase and an increase in the percentage of spleen and hepatosomatic index. The two stress situations produced changes in the FRAP (ferric reducing antioxidant power) levels in all organs studied with a particularly marked response for Diuron in the gill. No significant differences in the ROS (reactive oxygen species) level were found for the digestive tract or the gill. In muscle, only Diuron produced a significant increase in ROS, while in liver, both treatments increased the ROS levels. This supports the oxidative stress sensitivity to chemical stress and shows that also could be an appropriate indicator of handling stress. The morphological indexes and body components examined could be practical and easy welfare indicators. Nevertheless, further works must be needed to use under the production conditions in fish farms. [ABSTRACT FROM AUTHOR]

Abstract: Fish are often exposed to various molecules like pesticides. Some of these compounds get biomagnified within aquatic food web, inducing health hazards of consumers. However, behaviors of many pesticides are still unknown. This work aims to study the uptake and the elimination of some of them in muscle tissue of edible fish (azoxystrobin, clomazone, diflufenican, dimethachlor, carbendazim, iprodion, isoproturon, mesosulfuron-methyl, metazachlor, napropamid, quizalofop, and thifensulfuron-methyl). Two freshwater fish species (Perca fluviatilis and Cyprinus carpio) were exposed to a mixture of these 13 pesticides, via multi-contaminated pellets, and then, eliminated. Compounds were measured in food, water and muscle tissue using multi-residues methods. Kinetics, biomagnification factors (BMFs) and half-lives (t1/2) were estimated and they did not show a large difference between the species. Muscular BMFs ranged from 2×10−6 (mesosulfuron-methyl in perch) to 1×10−3 (isoproturon and napropamid in perch) and t1/2 ranged from 0.8 (mesosulfuron-methyl in perch) to 40.3d (napropamid in carp). BMFs were also modeled as a function of K ow value. All BMF values were explained by the model, except for diflufenican which had a BMF lower than that expected by our modeling work, probably due to an efficient metabolism. Results led to the conclusion that none of these chemicals would probably be biomagnified within aquatic food webs. [Copyright &y& Elsevier]

Abstract: Zebrafish, during embryo, larvae and adult stages were selected to investigate the potential environmental risk and aquatic toxicity of a widely used fungicide, difenoconazole. In addition to mortality, embryo development endpoints, teratogenic effects and behavior abnormity were measured. Finally, the developmental parameters of the adult fish were assessed after 14 days'' exposure. This study concluded that the acute toxicity of difenoconazole to the three phases of zebrafish were larvae (1.17 mg/L) > adult fish (1.45 mg/L) > embryo (2.34 mg/L). A large suite of symptoms was induced in embryonic development by different dosages of difenoconazole, including hatching inhibition, abnormal spontaneous movement, slow heart rate, growth regression and morphological deformities. 0.50 mg/L of difenoconazole could cause significant body color blackening and decrease in the heart rate of zebrafish larvae over 24 h. In addition, 0.25 mg/L of difenoconazole apparently inhibited the growth weight of adult zebrafish measured after 14 days'' exposure. [Copyright &y& Elsevier]

Abstract: This study evaluated the dietary uptake kinetics and sublethal toxicity of p,p′-dichlorodiphenyl dichloroethylene (p,p′-DDE) in Antarctic krill. The uptake rate constant (characterised by the seawater volume stripped of contaminant sorbed to algae) of 200 ± 0.32 mL g−1 wet weight h−1, average absorption efficiency of 86 ± 13% and very low elimination rate constant of 5 × 10−6 ± 0.0031 h−1 demonstrate the importance of feeding for p,p′-DDE bioaccumulation in Antarctic krill. Faecal egestion of unabsorbed p,p′-DDE of 8.1 ± 2.7% indicates that this pathway contributes considerably to p,p′-DDE sinking fluxes. A median internal effective concentration (IEC50) of 15 mmol/kg lipid weight for complete immobility indicates baseline toxicity and that Antarctic krill exhibit comparable toxicological sensitivity as temperate species under similar 10 d exposure conditions. These findings support the critical body residue approach and provide insight to the role of Antarctic krill in the biogeochemical cycling of p,p′-DDE in the Southern Ocean. [Copyright &y& Elsevier]

The study was carried out to determine the levels of organochlorine pesticide residue in five fish species Chrysichthys nigrodigitatus, Hepsetus odoe, Tilapia zilli, Heterotis niloticus and Oreochromis niloticus from the Densu river basin (Weija) in Ghana. The fishes sampled from the Weija fish landing site were selected on the basis of their importance to local human fish consumption. The detectable organochlorine pesticides were γ-Hexachlorocyclohexane (HCH), δ-Hexachlorocyclohexane, aldrin and dieldrin. Others investigated were alpha endosulfan, endosulfan sulfate, p,p'-DDT and its metabolite p,p'-DDE, endrin and its metabolite endrin aldehyde and endrin ketone. The total contamination levels of the individual fishes varied in the decreasing order of 9.19 ng g ( O. niloticus), 4.16 ng g ( T. zilli), 3.69 ng g ( C. nigrodigitatus), 3.68 ng g ( H. odoe) and 3.09 ng g ( H. niloticus). The highest organochlorine pesticide residue recorded in the study was alpha-endosulfan while dieldrin was the least pesticide observed. Analysis of variance indicated significant statistical differences for most organochlorine pesticide residues in the samples. The levels of organochlorine pesticides found in fish samples in the study were below maximum residue limit for food safety stipulated by EU, US FDA, FAO, Italy and Australia and thus safe for human consumption. [ABSTRACT FROM AUTHOR]

The OECD test guideline 203 for determination of fish acute toxicity requires substantial numbers of fish and uses death as an apical end point. One potential alternative are fish cell lines; however, several studies indicated that these appear up to several orders of magnitude less sensitive than fish. We developed a fish gill cell line-based (RTgill-W1) assay, using several measures to improve sensitivity. The optimized assay was applied to determine the toxicity of 35 organic chemicals, having a wide range of toxicity to fish, mode of action and physicochemical properties. We found a very good agreement between in vivo and in vitro effective concentrations. For up to 73% of the tested compounds, the difference between the two approaches was less than 5-fold, covering baseline toxicants but as well compounds with presumed specific modes of action, including reactivity, inhibition of acetylcholine esterase or uncoupling of oxidative phosphorylation. Accounting for measured chemical concentrations eliminated two outliers, the hydrophobic 4-decylaniline and the volatile 2,3-dimethyl-1,3-butadiene, with an outlier being operationally defined as a substance showing a more than 10-fold difference between in vivo/in vitro effect concentrations. Few outliers remained. The most striking were allyl alcohol (2700-fold), which likely needs to be metabolically activated, and permethrin (190-fold) and lindane (63-fold), compounds acting, respectively, on sodium and chloride channels in the brain of fish. We discuss further developments of this assay and suggest its use beyond predicting acute toxicity to fish, for example, as part of adverse outcome pathways to replace, reduce, or refine chronic fish tests. [ABSTRACT FROM AUTHOR]

Legacy halogenated compounds, including polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and emerging organo-halogen pollutants such as Dechlorane Plus (DP), were detected in fish from an old industrial region in Northeast China. PCBs and PBDEs were detected in all of the samples, with concentrations ranging from 38.15 to 170.51 ng/g lipid weight, and 9.40–39.69 ng/g lipid weight, respectively. DP was detected in more than 90% of the samples with concentrations ranging from not detected (ND) to 470 pg g/g lipid weight. Compared with similar data in other areas of the world, PCBs, PBDEs and DP in fish from Liaohe River were at medium or low level. An unusually high percentage of PCB-209 was first reported in the fish samples collected from China. Other halogenated pollutions, such as dichlorodiphenyltrichloroethane (DDT) and its metabolites, octachlorostyrene, chlorinated anisole, chlorinated thioanisole, triclosan-methyl, and other pesticides, have also been identified in the fish samples. [Copyright &y& Elsevier]

Salmon populations in the Pacific Northwest are being affected by a variety of environmental stressors including intense fishing pressure, parasites and disease, climatic variability and change, land development, hatchery production, hydropower operations, stormwater runoff, and exposure to toxic contaminants. In recent years, there has been much concern that mixtures of pesticides are causing toxic effects to Pacific salmon. In this study, we compared measured stream water concentrations from 2 monitoring studies conducted in the Pacific Northwest with concentration-response curves derived for inhibition of brain acetylcholinesterase activity in juvenile coho salmon ( Oncorhynchus kisutch) for mixtures of organophosphate (OPs) and carbamate (CBs) pesticides. In the first monitoring study, samples were collected from 2003 to 2007 in salmonid-bearing waters of 5 urban or agricultural watersheds in Washington State. This study was targeted to areas of high pesticide use and generally involved weekly sampling during the pesticide use season. The second monitoring study was the United States Geological Survey National Water Quality Assessment that included samples taken from 2003 to 2010 in California, Idaho, Oregon, and Washington. OPs and CBs were frequently detected in both studies. The available monitoring data collected since 2003, however, demonstrates that mixtures of OPs and CBs in surface waters rarely occur at levels capable of producing significant physiological and behavioral effects in Pacific salmon. The observed mixtures never reached concentrations capable of causing mortality. We conclude that mixtures of organophosphates and carbamates do not pose a significant direct risk to Pacific salmon. Integr Environ Assess Manag 2013; 9: 70-78. © 2012 SETAC [ABSTRACT FROM AUTHOR]

Twelve widely used pesticides were selected to investigate possible chemical, biological and toxicological effects of expired pesticides that may enter into our ecosystem. The selected compounds were tested for acute toxicity to Catla catla under static condition. Five to six concentrations (ranges from 0.005 - 80 mg I/1) of both expired and unexpired pesticide formulations were tested along with controls under similar conditions. The results of the LC50 (Lethal Concentration) demonstrated lower LC50 values for the expired pesticides as compared to the corresponding unexpired counter part. From this data, it is clear that expired pesticide formulations must be disposed carefully and care should be taken to avoid their discharge to water bodies and thus prevent loss to fish. [ABSTRACT FROM AUTHOR]

Intensive use of pesticides, particularly dithiocarbamates, in agriculture often leads to contamination of freshwater ecosystems. To our knowledge, the mechanisms of toxicity to fish by the carbamate fungicide Tattoo that contains mancozeb [ethylenebis(dithiocarbamate)] have not been studied. The present study aimed to evaluate the effects of Tattoo on goldfish gills and blood, tissues that would have close early contact with the pollutant. Exposure of goldfish Carassius auratus to 3, 5 or 10mgL−1 of Tattoo for 96h resulted in moderate lymphopenia (by 8 percent) with a concomitant increase in both stab (by 66–88 percent) and segmented (by 166 percent) neutrophils. An increase in the content of protein carbonyl groups in blood (by 137–184 percent) together with decreased levels of protein thiols (by 23 percent) and an enhancement of lipid peroxide concentrations (by 29 percent) in gills after exposure to 10mgL−1 of Tattoo demonstrated the induction of mild oxidative stress in response to Tattoo exposure. At the same time, the activities of selected antioxidant enzymes were enhanced in gills: superoxide dismutase by 18–25 percent and catalase by 27 percent. A 34 percent increment in low molecular mass thiol concentrations (mainly represented by glutathione) also occurred in gills and could be related to increased activity (by 13–30 percent) of glucose-6-phosphate dehydrogenase. The results indicate that Tattoo exposure perturbs free radical processes, i.e. induces mild oxidative stress and enhances the activity of certain antioxidant and associated enzymes in goldfish gills. It is clear that goldfish respond to the presence of waterborne pesticide by adjusting antioxidant defenses through upregulation of activities of antioxidant and associated enzymes. [Copyright &y& Elsevier]

Organophosphate pesticides must be metabolized by cytochrome-P450 isoenzymes such CYP 2C19 as CYP 3A4 to induce neurotoxicity, but damage apparently depends on the activity of aryl esterases of the oxonase type that are involved in detoxication of these compounds. However, information on this subject is not available in fish. Chirostoma jordani has sustained significant population reductions, probably due to changes in land-use as well as pesticide impact; nevertheless, no specific studies demonstrating this are available. This study shows for the first time that the activity of cytochrome-P450 isoenzymes (CYP 2B6, CYP 2C19, CYP 3A4) in C. jordani is involved in diazinon and chlorpyrifos bioactivation. However, higher toxicity of chlorpyrifos cannot be explained solely because its bioactivation. Differences in toxicity between both pesticides are due to the activity of aryl esterases and oxonases that are responsible for oxon detoxication. Both hepatic enzymes metabolize diazoxon more efficiently than chlorpyrifos oxon. At lethal concentrations, detoxication is particularly important since mortality was lower with diazinon (LC50=1.5μg/L) than with chlorpyrifos (LC50=0.17μg/L). At sublethal levels, maximum acetylcholinesterase inhibition took place at 4h in both brain and muscle and was of lower magnitude in diazinon-treated fish. This is due to the higher affinity of both aryl esterases for diazoxon, which allows higher detoxication rates and therefore greater recovery of acetylcholinesterase activity. [Copyright &y& Elsevier]

To evaluate the potential role of endocrine disruption in the decline of pelagic fishes in the San Francisco Bay Delta of California, various surface water samples were collected, extracted, and found to elicit estrogenic activity in laboratory fish. Chemical analysis of the estrogenic samples indicated 2 pesticides (bifenthrin, diuron), 2 alkyphenols (AP), and mixtures of 2 types of alkyphenol polyethoxylates (APEOs). Evaluation of estrogenic activity was further characterized by in vitro bioassays using rainbow trout hepatocytes (Oncorhynchus mykiss) and in vivo studies with Japanese medaka (Oryzias latipes). In the in vitro bioassays, hepatocytes exposed to the pesticides alone or in combination with the AP/APEO mixtures at concentrations observed in surface waters failed to show estrogenic activity (induction of vitelloginin mRNA). In the in vivo bioassays, medaka exposed to individual pesticides or to AP/APEO alone did not have elevated VTG at ambient concentrations. However, when the pesticides were combined with AP/APEOs in the 7-day exposure a significant increase in VTG was observed. Exposure to a 5-fold higher concentration of the AP/APEO mixture alone also significantly induced VTG. In contrast to earlier studies with permethrin, biotransformation of bifenthrin to estrogenic metabolites was not observed in medaka liver microsomes and cytochrome P450 was not induced with AP/APEO treatment. These results showed that mixtures of pesticides with significantly different modes of action and AP/APEOs at environmentally relevant concentrations may be associated with estrogenic activity measured in water extracts and feral fish that have been shown to be in population decline in the San Francisco Bay Delta. [ABSTRACT FROM AUTHOR]

Abstract: The investigation of biomagnification of polycyclic aromatic hydrocarbons (PAHs) and endosulfan, an organochlorine pesticide (OCP) and a new persistent organic pollutant, has been limited in freshwater food chains. The objective of the present study was to investigate the levels with focus on the sources and biomagnification of PAHs and OCPs in fish from Taihu Lake, China. In 193 samples of 24 species investigated, the concentrations ranged from 289 to 9 500ng/g lipid weight (lw) for PAHs, and from 121 to 904ng/g lw for OCPs, indicating that the fish in the lake was moderately contaminated. The PAHs mainly originated from both unburned petroleum and combustion of fossil fuels, and the OCPs from aged residues. It was unlikely that most of the PAHs and OCPs were biodiluted through the food chain because their trophic magnification factors were higher than one nevertheless the P-values >0.05. Aldrin, dieldrin, p,p′-DDE, p,p′-DDD, and endosulfan sulfate were significantly biomagnified through the food chain. [Copyright &y& Elsevier]

Pyrethroids belong to the most commonly used pesticides worldwide. Their massive expansion is a threat to the natural environment including the aquatic ecosystems. Although pyrethroids are rapidly degraded in soil and plants, they are extremelytoxic to fish because of fish high sensitivity to them. Pyretiroids are divided by characteristic into type land type II. Both types cause similar neurological symptoms. They affect sodium channels of nerve filaments and type II pyrethroids even affect chloride and calcium channels. Critical in fish pyrethroid intoxication is slower elimination than in birds and mammals. Pyrethroids are absorbed by fish gills readily. After distribution to bile, liver, kidney and red blood cells, they are metabolized by hydrolysis, hydroxylation and conjugation to glucuronides and sulphates. Disorders of movement and breathing during acute poisoning are followed by death. Chronic effects of pyrethroids induce behaviour changes, blood profile changes, histopathological changes, decreased growth, immune system effects and endocrine effects. Both types of toxicity reduce reproductive potential. Toxicity of pyrethroids depends on many external and internal factors. [ABSTRACT FROM AUTHOR]

Abstract: The Stepwise Behavioral Response Model (SBRM), which is a conceptual model, postulated that an organism displays a time-dependent sequence of compensatory Stepwise Behavioral Response (SBR) during exposure to pollutants above their respective thresholds of resistance. In order to prove the model, in this study, the behavioral responses (BRs) of medaka (Oryzias latipes) in the exposure of Arprocarb (A), Carbofuran (C) and Methomyl (M) were analyzed in an online monitoring system (OMS). The Self-Organizing Map (SOM) was utilized for patterning the obtained behavioral data in 0.1 TU (Toxic Unit), 1 TU, 2 TU, 5 TU, 10 TU and 20 TU treatments with control. Some differences among different Carbamate Pesticides (CPs) were observed in different concentrations and the profiles of behavior strength (BS) on SOM were variable depending upon levels of concentration. The time of the first significant decrease of BS (SD-BS) was in inverse ratio to the CP concentrations. Movement behavior showed by medaka mainly included No effect, Stimulation, Acclimation, Adjustment (Readjustment) and Toxic effect, which proved SBRM as a time-dependence model based on the time series BS data. Meanwhile, it was found that SBRM showed evident stress-dependence. Therefore, it was concluded that medaka SBR was both stress-dependent and time-dependent, which supported and developed SBRM, and data mining by SOM could be efficiently used to illustrate the behavioral processes and to monitor toxic chemicals in the environment. [Copyright &y& Elsevier]

Pesticides applied on land are commonly transported by runoff or spray drift to aquatic ecosystems, where they are potentially toxic to fishes and other nontarget organisms. Pesticides add to and interact with other stressors of ecosystem processes, including surface-water diversions, losses of spawning and rearing habitats, nonnative species, and harmful algal blooms. Assessing the cumulative effects of pesticides on species or ecological functions has been difficult for historical, legal, conceptual, and practical reasons. To explore these challenges, we examine current-use (modern) pesticides and their potential connections to the abundances of fishes in the San Francisco Estuary (California). Declines in delta smelt (Hypomesus transpacificus), Chinook salmon (Oncorhynchus tshawytscha), and other species have triggered mandatory and expensive management actions in the urbanizing estuary and agriculturally productive Central Valley. Our inferences are transferable to other situations in which toxics may drive changes in ecological status and trends. [ABSTRACT FROM AUTHOR]

Contamination with agricultural pesticides such as dichlorodiphenyltrichloroethane (DDT) and its metabolites, dichlorodiphenyldichloroethylene (DDE) and dichlorodiphenyldichloroethane (DDD), is among several proposed stressors contributing to the global declines in amphibian populations and species biodiversity. These chemicals were examined in insects and in the muscle, liver, and eggs of rice frogs ( Rana limnocharis) from the paddy fields of an agricultural site in South China. The ΣDDT (sum of DDT, DDE, and DDD) concentrations ranged from 154 to 915, 195 to 1,400, and 165 to 1,930 ng/g lipid weight in the muscle, liver, and eggs, respectively. All the DDTs (DDT, DDE, and DDD) showed higher affinity for the liver relative to muscle tissue and can be maternally transferred to eggs in female frogs. The average biomagnification factors for DDTs ranged from 1.6 to 1.9 and 1.5 to 2.9 in female and male frogs, respectively, providing clear evidence of their biomagnification from insects to frogs. Compared with the reported DDT levels demonstrated to have toxic effects on frogs, DDTs in the present frogs are unlikely to constitute an immediate health risk. However, the adverse impacts of high DDT residues in eggs on the hatching success and their potential toxicity to the newly metamorphosed larval frogs should be assessed further. Environ. Toxicol. Chem. 2012;31:705-711. © 2011 SETAC [ABSTRACT FROM AUTHOR]

The cytotoxic and genotoxic effects induced by alachlor and dichlorvos, two pesticides broadly used, were studied on RTG-2 fish cell line. As measure of cytotoxicity, neutral red assay was used to determine the cellular viability. Toxicity ranking based on IC50 values found that alachlor was more cytotoxic than dichlorvos. DNA damage has been evaluated on RTG-2 cultures by means of an in vitro assay based on the ability of PicoGreen® fluorochrome to interact preferentially with double-stranded DNA (dsDNA), and the results indicated that alachlor induced DNA strand breaks at concentrations above 1.52 μg/mL, equivalent to 1/50-EC50(48), whereas exposures to dichlorvos induced DNA damage only at the maximal concentrations tested 25 μg/mL (1/10-EC50(48)). These results confirm the suitability of this method for the screening of genotoxic effects of this type of aquatic pollutants, and we suggest their use in hazard assessment for environmental risk procedures. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012. [ABSTRACT FROM AUTHOR]

The effects of a 90 day simazine exposure at concentrations of 0.06 (reported concentration in Czech rivers), 1, 2, and 4μgL−1 were assessed in one-year-old common carp (Cyprinus carpio L.). Its influence on biometric parameters, hematology, blood biochemistry, liver biomarkers, and histology was investigated. Biometric parameters of common carp exposed to simazine at 0.06μgL−1 showed no differences from untreated fish. Simazine concentrations of 1, 2, and 4μgL−1 caused significant (p<0.01) increase of hepatosomatic indices relative to controls. Hematological profiles showed significant (p<0.01) decrease in leukocyte count relative to controls at all concentrations. Biochemical profiles of common carp exposed to simazine at all concentrations showed significant (p<0.01) increase in activity of alkaline phosphatase. In addition, at concentrations of 1 and 2μgL−1, there was a significant increase in alanine aminotransferase (p<0.05), and, at 4μgL−1, a significant increase in total protein (p<0.05), albumins (p<0.05), and alanine aminotransferase (p<0.05) compared with controls. Renal histology revealed severe hyaline degeneration of the epithelial cells of caudal kidney tubules in fish at all exposure levels compared to controls. Chronic exposure of common carp to simazine caused significant shifts in hematological, biochemical, and biometric profiles, and histopathological changes. The results of this study indicate that chronic exposure of simazine has altered multiple physiological indices in fish hematology and biochemistry, which potentially may be a biomarker of simazine toxicity; however, before these parameters are used as special biomarkers for monitoring residual simazine in aquatic environment, more detailed experiments in laboratory need to be performed in the future. [Copyright &y& Elsevier]

Endosulfan is an organochlorine pesticide, which is used worldwide and has known toxic effects on non-target organisms including fish. This research investigated the acute and chronic effects of pulse-exposed endosulfan on Florida flagfish (Jordanella floridae). A 4-h pulse-exposure of endosulfan to larval flagfish caused a significant increase in mortality after 96h at nominal concentrations equal to or greater than 100μg/L. Some of the acute sub-lethal observations included hyperactivity, convulsions, and axis malformation. Seven-eight day old post-hatch flagfish were pulse-exposed for 4h to endosulfan and then monitored over one full life-cycle for chronic effects on growth, reproduction, and survivability. There were no growth or reproductive effects of endosulfan pulse-exposure up to the highest exposure concentration of 10.8μg/L. Thus, the life-cycle 4-h pulse-exposure no observed effect concentration (NOEC) and lowest observed effect concentration (LOEC) were 3.3 and 10.8μg/L endosulfan, respectively, based on significantly higher larval and juvenile mortality. [Copyright &y& Elsevier]

Flounders ( Platichthys flesus) from the waters around Denmark were analysed for their organochlorine (OC) profile to study whether fish from the same genetic population could be separated into characteristic subpopulations, based on their feeding grounds. The chemical analysis of fish liver provided a data set of 16 OC compounds in 94 samples from 2004 to 2006. Except for hexachlorocyclohexane, OC compounds were intercorrelated, indicating similar environmental fate and bioaccumulation. OC profiles are less affected than absolute concentrations by potentially confounding biological factors and thus more suitable for studies of intrapopulation differences in relation to feeding grounds. Principal component analysis grouped the samples according to locations. All but three of the 94 samples could be reclassified. Samples from the same and additional locations collected in 2003 provided validation, with only few misclassifications. This statistical separation likely reflects location-specific pollutant patterns in sediments and biota, even on the relatively small scale of this study. Thus, despite the lack of genetic differences, characteristic subpopulations of flounders could be identified with separate feeding grounds. OC profiles have been used increasingly to distinguish stocks. [ABSTRACT FROM AUTHOR]

The effects of dimethoate on hematological, biochemical parameters, and behavior were investigated in Oncorhynchus mykiss exposed to sublethal concentrations of 0.0735, 0.3675, and 0.7350 mg/l for 5, 15, and 30 days. Significant decrease was determined in erythrocyte and leukocyte counts, hemoglobin, hematocrit, MCV, and MCH, which was pronounced after prolonged exposure indicating the appearance of microcytic hypochromic anemia. There were no prominent changes in thrombocyte and MCHC. The glucose concentration showed an ascending pattern that proved to be positively correlated with duration. The protein concentration declined in higher dimethoate concentrations following 15 and 30 days. Negative and significant correlation was detected between glucose and protein concentrations. The fish showed remarkable behavioral abnormality such as loss of balance, erratic swimming, and convulsion. Present findings revealed that dimethoate exerts its toxic action even in sublethal concentrations and hematological parameters and abnormal behavior may be sensitive indicators to evaluate pesticide intoxication. [ABSTRACT FROM AUTHOR]

Abstract: Pressurized liquid extraction (PLE) combined with in-cell clean-up of co-extracts, so-called selective-PLE (S-PLE), is a fast and accepted method for the analysis of halogenated organic contaminants in fish. However, many of the existing methods were optimized for use with single classes of contaminants. The main objective of this research was to develop an S-PLE method that elutes a minimal amount of fats while simultaneously extracting halogenated pesticides, polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) from fat-rich fish. The optimized method uses n-hexane:dichloromethane (75:25, v/v) as the extraction solvent, a 0.0078 fat to fat-retainer ratio (FFR) with Florisil as the fat retainer, three individual 5-min extractions with flush volumes of 150% and a selection of labeled surrogate standards (isotope dilution). This method resulted in a mean recovery of 77% for all target analytes in spiked samples and an average relative standard deviation of 6.3%. The method was validated with a certified reference material; the mean measured analyte concentrations agreed with the reference values except in the case of individual endosulfan isomers. It is likely that interconversion from the beta- to alpha-endosulfan isomer had occurred in the CRM, resulting in low measured concentrations for beta-endosulfan and high measured concentrations for alpha-endosulfan when compared with the reference values. Finally, the method was tested on three fish species with varying fat content. Different contaminant patterns were observed in the various species. [Copyright &y& Elsevier]

Abstract: The QuEChERS method developed for 22 organochlorine pesticides (OCPs) and 7-polychlorinated biphenyls (PCBs) in fish tissue involves a simple and efficient freezing technique for removal of lipids. The equipment developed consists of disposable syringes and a freezing block constructed from simple materials found in most laboratories. The freezing block keeps the temperature in the extract at −20.5°C up to 10min after being exposed to room temperature. After the freezing step 69% of the lipids in tilapia and 61% in salmon are removed. Further reduction of co-extractives up to 96% in tilapia and 87% in salmon can be made by treatment with CaCl2 and primary secondary amino sorbent (PSA) which removes the fatty acids. Spiking experiments in tilapia at 5 and 50ng/g and extracted with acetonitrile show recovery range from 70 to 115% for all compounds. In salmon the recoveries are in the range 43–118% for the OCPs and 26–65% for the PCBs. Analysis of a standard reference material shows acceptable results for most of the pesticides but low results for the PCBs. The estimated LOQs were in the range 1–5ng/g for tilapia and 2–10ng/g for salmon. The method has been applied to analyse fish samples from Lake Koka in Ethiopia. It was investigated if addition of a less polar water miscible solvent than acetonitrile could increase the recovery of OCPs and PCBs. The results show that a mixture of 75% acetonitrile and 25% tetrahydrofurane (ACN/THF 75/25) clearly enhances the recoveries for most OCPs (47–101%) and PCBs (42–79%) from salmon. The recovery of aldrin increases significantly from 55% to over 80%. The method using ACN/THF 75/25 is applicable to the extraction of OCPs and PCBs from fish tissue having a lipid content of up to about 11% (salmon) with recoveries ≥70% for most of the OCPs and ≥42% for the PCBs. [Copyright &y& Elsevier]

Abstract: Hollow fiber liquid-phase microextraction (HF-LPME) technique was used as a clean-up procedure for the determination of organophosphorus pesticides (OPPs) in fish tissue. In this study, eight OPPs were first extracted with acetone from fish sample, the organic extract after rotatory evaporation was then redissolved with water–methanol (95:5, v/v) solution, followed by polyvinylidene difluoride (PVDF) HF-LPME. Experimental HF-LPME and other sample preparation conditions were carefully investigated and optimized. Under the optimum conditions, good linearity were observed in the range of 20–500ng/g, limits of detections (LODs) were in the range of 2.1–4.5ng/g. The repeatability and recovery of the method also showed satisfactory results. Compared with traditional sample preparation method for the determination of OPPs in fish tissue, the method developed in this study eliminated the solid phase extraction (SPE) step, simplified the sample preparation procedure and lowered the cost of analysis. [Copyright &y& Elsevier]

Abstract: The impact of acute and sublethal toxicity of a synthetic organochlorine pesticide lindane on some haematological and biochemical parameters of a freshwater fish Cyprinus carpio was estimated. The median lethal concentration of lindane for 24h was 0.38ppm. During acute treatment (24h), hemoglobin (Hb), hematocrit (Hct) and erythrocyte (RBC) values were decreased, whereas leucocyte (WBC) count increased in the pesticide treated fish. The hematological indices like mean cellular volume (MCV), mean cellular hemoglobin (MCH) and mean cellular hemoglobin concentration (MCHC) were decreased when compared to control group. Biochemical profiles like plasma glucose and protein levels were increased in lindane exposed fish showing a percent increase of 50.36 and 3.98 at the end of 24h treatment. However, glycogen content in liver and muscle were decreased showing a percent decrease of 21.70 and 1.74. In sublethal treatment (1/10th of LC50 24h value, 0.038ppm), RBC count was decreased whereas WBC count increased in the pesticide treated fish throughout the study period (25days). Hb and Hct values were decreased up to 10th day and after that recovered showing a significant increase in the rest of the study period. Similarly, a biphasic response was observed in the value of MCV, MCH and MCHC. Plasma glucose level was significantly increased while plasma protein level decreased throughout the study period. Further, glycogen level in muscle and liver were showed a mixed trend. In the present study, the pesticide lindane caused alterations on haematological and biochemical parameters of C. carpio and these alterations can be used as non specific biomarkers in pesticide contaminated aquatic ecosystem. [Copyright &y& Elsevier]

Forty-seven fish (24 endemic Alburnus tarichi, Güldenstädt, 1814; 8 Capoeta capoeta, Guldenstaedt, 1772; 15 mirror carp Cyprinus carpio, L., 1758) and 13 mussel ( Unio stevenianus, Krynicki, 1837) samples, with 10 specimens per sample, were collected from Van Lake, Turkey, and rivers flowing into it. Gamma-HCH was detected in 21 Alburnus tarichi samples (56.57 ng/g ± 22.18 ng/g) and in two Capoeta capoeta samples (27.6 ng/g and 36.45 ng/g). Beta-HCH was detected in 8 Alburnus tarichi samples (24.95 ng/g ± 4.42 ng/g) and in two mussel samples (101.25 ng/g and 129.44 ng/g). HCB was found in one Alburnus tarichi sample (14.4 ng/g) and one mussel sample (181.25 ng/g). The compound 4,4′-DDE was detected in 21 Alburnus tarichi samples (87.13 ng/g ± 32.23 ng/g), in 9 mirror carp samples (304.82 ng/g ± 100.76 ng/g) and one mussel sample (149.31 ng/g). PCB 28 was detected in one Alburnus tarichi (19.46 ng/g) sample and PCB 101 was found in one Capoeta capoeta (60.16 ng/g) sample. PCB 118 was detected in one mirror carp sample (277.5 ng/g) and in two Capoeta capoeta samples (43.77 and 54.38 ng/g). PCB 128 was detected in only one Capoeta capoeta sample (141.48 ng/g). It is concluded that (i) efforts should be made to reduce contamination of aquatic environments by these compounds and that (ii) their levels in fishery products from Van Lake and connected streams should be monitored and publicly reported on a regular basis. [ABSTRACT FROM AUTHOR]

Abstract: The present study was conducted in order to investigate pro-oxidant activity of dimethoate in liver and brain tissues following sublethal pesticide exposure for 5, 15 and 30d by using SOD, GPx, CAT enzyme activities and lipid peroxidation as biomarkers as well as DNA damaging potential via detecting% Tail DNA, Tail moment and Olive tail moment as endpoints in erythrocytes of Oncorhynchus mykiss in an in vitro experiment. Antioxidant enzyme activities were found to elicit two staged response which was an initial induction followed by a sharp inhibition in liver tissue while a sustained increase in GPx activity and slight stimulation in SOD activity were detected in brain tissue. Lipid peroxidation showed an ascending pattern throughout the exposure period in both tissues and a decreasing trend was determined in tissue protein levels which was proved to be positively correlated with duration. Similar findings were obtained from outcomes preferred to quantify DNA damage and TM was decided to reflect the extent of damage more sensitively because of determined positive correlation with concentrations applied. Considering these results, it can be concluded that oxidative stress condition evoked by dimethoate could not be responded effectively and genotoxic nature of pesticide was proven by determined clastogenic effect possibly via being an alkylation agent or stimulating the production of reactive species. [Copyright &y& Elsevier]

Abstract: In this study, fish Rhamdia quelen, were exposed to different concentrations of herbicide clomazone: 0.0 (control), 0.45 and 0.91mgL−1. After exposure for 8days to herbicide, fish were transferred to clean water for a recovery period (8days). Oxidative stress indicators such as thiobarbituric acid reactive substances (TBARS) levels and protein carbonyl content, as well as antioxidant defenses, such as catalase (CAT), superoxide dismutase (SOD), glutathione S-transferase (GST), ascorbic acid and non-protein thiols levels were studied, using the liver, brain and muscle tissues. Herbicide exposure increased TBARS in muscle and in liver at higher concentration. In liver protein carbonylation increased and catalase activity did not change in fish exposed to herbicide. SOD enhanced in liver at concentration of 0.91mgL−1. GST, ascorbic acid and non-protein thiols levels increase at both concentrations. At the end of the recovery period the most of the parameters recovered whereas GST and ascorbic acid remain elevated. The present study demonstrates the occurrence of disorders in antioxidant parameters and importance in the assessment of the potential risk of herbicides as clomazone on fish species. [Copyright &y& Elsevier]

The ability of targeted and nontargeted metabolomics to discover chronic ecotoxicological effects is largely unexplored, Fenitrothion, an organopho-sphate pesticide, is categorized as a "red Ust" pollutant, being particularly hazardous to aquatic life. It acts primarily as a Cholinesterase inhibitor, but evidence suggests it can also act as an androgen receptor antagonist Whole-organism fenitrothion-induced toxicity is well-established, but information regarding target and off-target molecular toxicities is limited. Here we study the molecular responses of male roach (Rutilus rutilus) exposed to fenitrothion, including environmentally realistic concentrations, for 28 days. Acetylcholine was assessed in brain; steroid metabolism was measured in testes and plasma; and NMR and mass spectrometry-based metabolomics were conducted on testes and liver to discover off-target toxicity. O-demethylation was confirmed as a major route of pesticide degradation. Fenitrothion significantly depleted acetylcholine, confirming its primary mode of action, and 11-ketotestosterone in plasma and cortisone in testes, showing disruption of steroid metabolism. Metabolomics revealed significant perturbations to the hepatic phosphagen system and previously undocumented effects on phenylalanine metabolism in liver and testes. On the basis of several unexpected molecular responses that were opposite to the anticipated acute toxicity, we propose that chronic pesticide exposure induces an adapting phenotype in roach, which may have considerable implications for interpreting molecular biomarker responses in field-sampled fish. [ABSTRACT FROM AUTHOR]

The risk assessment of pesticides for freshwater ecosystems in the Amazon has relied on the use of toxicity data and water quality criteria derived for temperate regions due to a lack of ecotoxicological studies performed with indigenous species. This leaves an unknown margin of uncertainty for the protection of Amazonian ecosystems, as differences in environmental conditions and species sensitivity are not taken into account. To address this issue, the acute toxic effects of malathion (an organophosphorus insecticide) and carbendazim (a benzimidazole fungicide) were assessed on five fish and five freshwater invertebrates endemic to the Amazonian region. Subsequently, the intrinsic sensitivity of Amazonian and temperate freshwater species was compared using the species sensitivity distribution (SSD) concept. Amazonian species sensitivity to malathion was found to be similar to that of their temperate counterparts, with LC50 values ranging between 111 and 1507 μg/l for fish species and 2.1-426 μg/l for arthropod species. However, Amazonian fish appeared to be slightly less sensitive for carbendazim than temperate fish with LC50 values ranging between 1648 and 4238 μg/l, and Amazonian invertebrates were found to be significantly more resistant than their temperate counterparts, with LC50 values higher than 16000 μg/l. The results of this study suggest that for these compounds, the use of water quality criteria derived with laboratory toxicity data for temperate species will result in a sufficient protection level for Amazonian freshwater organisms. Recommendations for further research include the validation of threshold concentrations derived with temperate standard test species and with the SSD model with semi-field experiments considering larger assemblages of indigenous species under local environmental conditions. [ABSTRACT FROM AUTHOR]

As a major ecosystem type, wetland provides invaluable ecological services. Environmental pollution, especially pesticides pollution should be paid more attention to keep wetlands healthy. Based on the risk quotient method, coupled with a probabilistic risk assessment model, this paper proposed a methodology suitable for ecological risk assessment of pesticide residues for wetland ecosystems. As an important industrializing and ecologically vulnerable area in China, the Taihu Lake wetland was chosen for the case study. The risks of eight pesticides in Taihu Lake wetland were assessed, as single substances and in mixtures. The assessment indicates that risks of the representative species are not significant. In general, the herbicide is found to be more toxic for algae, whereas insecticides pose more risks to zooplankton, insect and fish. For each pesticide in the wetland, the ecological risk it poses is acceptable. But the combined ecological risk posed by mixture can harm more than 10% of species of the wetland ecosystem, mainly dominated by dichlorvos, dimethoate and malathion contributions. These results imply that pesticide residues have been posing pressures on the ecosystem of the Taihu Lake wetland. It is recommended that proper countermeasures should be implemented to reduce the risks. [Copyright &y& Elsevier]

Abstract: Pesticides are nearly ubiquitous in surface waters of the United States, where they often are found as mixtures. The molecular mechanisms underlying the toxic effects of sub-lethal exposure to pesticides as both individual and mixtures are unclear. The current work aims to identify and compare differentially expressed proteins in brains of male fathead minnows (Pimephales promelas) exposed for 72h to permethrin (7.5μg/L), terbufos (57.5μg/L) and a binary mixture of both. Twenty-four proteins were found to be differentially expressed among all three treatments relative to the control using an ANOVA followed by a Dunnett''s post hoc test (p ≤0.05). One protein was found to be differentially expressed among all treatment groups and one protein was in common between the terbufos and the mixture group. Fifteen spots were successfully sequenced using LC–MS/MS sequencing. Proteins associated with the ubiquitin–proteasome system, glycolysis, the cytoskeleton and hypoxia were enriched. As a second objective, we attempted to establish protein expression signatures (PES) for individual permethrin and terbufos exposures. We were unable to generate a useable PES for terbufos; however, the permethrin PES was able to distinguish between control and permethrin-exposed individuals in an independent experiment with an accuracy of 87.5%. This PES also accurately classified permethrin exposed individuals when the exposure occurred as part of a mixture. The identification of proteins differentially expressed as a result of pesticide exposure represent a step forward in the understanding of mechanisms of toxicity of permethrin and terbufos. They also allow a comparison of molecular responses of the binary mixture to single exposures. The permethrin PES is the first step in establishing a method to determine exposures in real-world scenarios. [Copyright &y& Elsevier]

Abstract: The resistance of fish to microorganisms challenge depends mainly on the efficacy of the immune response. Most studies on the natural immune response of fish have focused on the effect of diets and immunostimulants. Few studies correlated the presence of commonly used agrichemical and susceptibility to infection by aquatic microorganism. Thus, this study aimed to investigate the effect of glyphosate and atrazine-based herbicides on immune cell phagocytosis and susceptibility of silver catfish to Aeromonas hydrophila infection. Following exposure to sublethal concentrations of glyphosate or atrazine (10% of the LC50–96 h), a significant decrease in the number of intracelomatic cells and phagocytic index could be observed. In addition, silver catfish fingerlings exposed to glyphosate or atrazine were more susceptible to intracelomatic challenge with pathogenic A. hydrophila. Thus, the presence of these herbicides on the water alters the natural immune response to bacterial and possibly to other aquatic microorganism. [ABSTRACT FROM AUTHOR]

The organophosphate pesticide chlorpyrifos significantly decreased the specific activities of catalase (CAT) and lactate dehydrogenase (LDH) in brain, liver, gill and skeletal muscle of the freshwater catfish, Heteropneustes fossilis. It may be due to binding of the pesticide or its metabolite(s) with the enzyme molecules or affecting the synthesis and/or degradation of the enzymes. RNA and protein content also declined significantly in different tissues of the fish in response to chlorpyrifos, which may be due to alterations in turnover of macromolecules involved in protein synthesis. Administration of thyroxine (T4) and ascorbic acid (vitamin C) separately or conjointly to chlorpyrifos-exposed fish brought CAT, LDH, RNA and protein up to their control levels. The protective effect may be attributed to hormone, vitamin and pesticide interaction. Therefore, chlorpyrifos-induced impairment in antioxidative, anaerobic and protein synthesizing capacity can be repaired by ascorbic acid and T4 in fish. [Copyright &y& Elsevier]

Abstract: Medetomidine is a new antifouling agent, and its effects in non-target aquatic organisms have been investigated. Earlier short-term studies in fish have shown a skin lightening response to medetomidine, but effects after chronic exposure have not been studied. In fish, the dark pigment melanin is contained within specialized cells, melanophores. Medetomidine binds to the melanophore α2-adrenoceptor, which stimulates pigment aggregation resulting in the light appearance. In the present study, rainbow trout (Oncorhynchus mykiss) was long-term exposed to 0.5 and 5.0nM of medetomidine via water for 54d. The fish were then photographed for paleness quantification and the images were analyzed using ImageJ analysis software. Additionally, scales were removed and used for in vitro function studies of the melanophores, monitoring the response to melanophore stimulating hormone (MSH) and subsequent medetomidine addition. The number of melanophores was also investigated. As a result of the medetomidine exposure, fish from the 5nM treatment were significantly paler than control fish and the melanophores from these fishes were also more aggregated. Melanophores from all the treatments were functional, responding to MSH by dispersion and to subsequent medetomidine by aggregation. However, the results indicate a difference in sensitivity among treatments. The number of melanophores in the scales did not change significantly after long term exposure to medetomidine. These results suggest that the observed paleness may be reversible, even after chronic exposure. [ABSTRACT FROM AUTHOR]

Background: Persistent organic pollutants (POPs), including polychlorinated biphenyls (PCBs) and chlorinated pesticides, have been shown to have many adverse human health effects. These contaminants therefore may pose a risk to Alaska Natives that follow a traditional diet high in marine mammals and fish, in which POPs bioaccumulate. Methods and Findings: This study examined the levels of PCBs and three pesticides [p, p9-DDE, mirex, and hexachlorobenzene (HCB)] in muscle tissue from nine fish species from several locations around the Aleutian Islands of Alaska. The highest median PCB level was found in rock sole (Lepidopsetta bilineata, 285 ppb, wet weight), while the lowest level was found in rock greenling (Hexagrammos lagocephalus, 104 ppb, wet weight). Lipid adjusted PCB values were also calculated and significant interspecies differences were found. Again, rock sole had the highest level (68,536 ppb, lipid weight). Concerning the PCB congener patterns, the more highly chlorinated congeners were most common as would be expected due to their greater persistence. Among the pesticides, p, p9-DDE generally dominated, and the highest level was found in sockeye salmon (Oncorhynchus nerka, 6.9 ppb, wet weight). The methodology developed by U.S. Environmental Protection Agency (USEPA) was used to calculate risk-based consumption limits for the analyzed fish species. For cancer health endpoints for PCBs, all species would trigger strict advisories of between two and six meals per year, depending upon species. For noncancer effects by PCBs, advisories of between seven and twenty-two meals per year were triggered. None of the pesticides triggered consumption limits. Conclusion: The fish analyzed, mainly from Adak, contain significant concentrations of POPs, in particular PCBs, which raises the question whether these fish are safe to eat, particularly for sensitive populations. However when assessing any risk of the traditional diet, one must also consider the many health and cultural benefits from eating fish. [ABSTRACT FROM AUTHOR]

Abstract: Acute toxicity of the pesticides, maneb and carbaryl, to juvenile rainbow trout were evaluated under static-renewal test conditions. Actual concentrations of maneb ranged from 0.10mg/L to 2.00mg/L and carbaryl ranged from 0.20mg/L to 3.90mg/L. The concentrations of maneb that killed 50% of the rainbow trout (3.27±0.9g) within 24-h (24-h; LC50), 48-h, 72-h and 96-h were 1.19±0.12, 1.04±0.11, 0.92±0.12 and 0.81±0.14mg/L (95% confidence limits), respectively. LC50 values of carbaryl for 24-h, 48-h, 72-h and 96-h were 2.52±0.71, 2.16±0.63, 1.71±0.46 and 1.39±0.15mg/L, respectively. None of the unexposed control fish died and the first fish died 6h after exposure to maneb (≥1.30mg/L), and carbaryl (≥2.60mg/L). Lamellar edema, separation of epithelium from lamellae, lamellar fusion, swelling of the epithelial cells and epithelial cell necrosis were observed on maneb and carbaryl exposed fish. Gills also had scattered areas of focal lamellar hyperplasia. Fish exposed to pesticides had inflammation and focal necrosis in liver, trunk kidney and spleen. Maneb and carbaryl had similar histopathological lesions. In order, the most affected organs were gill, trunk kidney and liver. [Copyright &y& Elsevier]