Microcystin and pyriproxyfen are toxic to early stages of development in Rhamdia quelen: An experimental and modelling study.

The recent increase of freshwater eutrophication has favored cyanobacteria blooms and consequently the increase of toxins such as microcystin-LR in aquatic environments, but few is know about the associated effect of toxin and other compounds. Pyriproxyfen is an insecticide indicated by WHO (World Health Organization) to control Aedes aegypti mosquito (vector of Dengue, Chikungunya and Zika diseases), however, the effects are not well described to non-target species, such as fish. The early life stages (ELS) of fish are more sensitive to chemical stress due to higher metabolic rate, immature immune system and high superficial area/volume ratio. In the current study, ELS of R. quelen a Neotropical fish were exposed to environmentally realistic concentrations of microcystin (1, 10 and 100 µg L-1; M1, M2 and M3 groups, respectively) from an algal extract, pyriproxyfen (1 and 10 µg L-1, P1 and P2) and their association (co-exposure). The hatching, survival and larvae deformities were analyzed, and applied a mathematical model to evaluate the effects on the population size along further generations. Both compounds were toxic to embryos/larvae of fish, but the effects were more pronounced in M2, P1M2 and P2M1 for hatching and M2, P1M2, P2M1 and P1 for survival. Deformities prevailed in groups exposed to the chemicals at 48 hpf (hours post-fertilization) were suggestions of toxicological interaction in P1M2, P2M1 and P2M2 at 48 and 72 hpf. In 96 hpf, the levels of deformities were lower than in previous times. Model predicted population density over 100 years decreased to lower than 0.5 (50%) in all groups, except for P1M1, indicating risk of extinction. P1M2 had the worse results, followed by M2, P1M3 and P2M1. Cyanobacterial blooms can lead to microcystin-LR levels higher than M2 (10 µg L-1), and the suggestion of toxicological interaction with pyriproxyfen is relevant because both compounds may potentially coexist in aquatic environments. Finally, mathematical models may provide an ecological interpretation of the risk of exposure of fish.

Cylindrospermopsin effects on cell viability and redox milieu of Neotropical fish Hoplias malabaricus hepatocytes.

Cylindrospermopsin (CYN) is a cyanotoxin that is cytotoxic to a wide variety of cells, particularly to the hepatocytes. In this study, the toxic effects of purified CYN were investigated in primary cultured hepatocytes of Neotropical fish Hoplias malabaricus. After isolation, attachment, and recovery for 72 h, the cells were exposed for 72 h to 0, 0.1, 1.0, 10, and 100 µg l-1 of CYN. Then, cell viability and a set of oxidative stress biomarker responses were determined. Catalase, superoxide dismutase, glucose-6-phosphate dehydrogenase, and glutathione S-transferase activities were not affected by exposure to CYN. Concentration-dependent decrease of glutathione reductase activity occurred for most CYN-exposed groups, whereas non-protein thiol content increased only for the highest CYN concentration. Lipid peroxidation, protein carbonylation, and DNA damage levels were not altered, but reactive oxygen species levels increased in the cells exposed to the highest concentration of CYN. Cell viability decreased in all the groups exposed to CYN. Thus, CYN may cause a slight change in redox balance, but it is not the main cause of cell death in H. malabaricus hepatocytes.

Resveratrol administration increases Transthyretin protein levels ameliorating AD features- importance of transthyretin tetrameric stability.

Previous in vivo work showed that resveratrol has beneficial effects in the AD pathology, resulting in increased expression of transthyretin (TTR). TTR binds Aß peptide avoiding its aggregation and toxicity, and is reduced in the CSF and plasma, in AD. Further, resveratrol binds TTR, stabilizing the native TTR tetrameric structure. To further explore the mechanism of neuroprotection conferred by TTR in AD, resveratrol was administrated, in the diet, to 5-8 months old AD transgenic female mice carrying just one copy of the mouse TTR gene, for two months. Effects in brain Aß burden were evaluated by immunohistochemistry, and in total brain Aß levels by ELISA, showing a striking decrease in both parameters in treated animals. In addition, total brain LRP1 protein levels were increased in treated animals, although its gene expression was unaltered. To further understand the mechanism(s) underlying such improvement in AD features, we measured TTR plasma levels showing that TTR increased in resveratrol-treated mice, whereas liver TTR gene transcription was not altered. These results strengthen the stability hypothesis, which postulates that TTR is unstable in AD leading to accelerated clearance and lower levels. Therefore, resveratrol which stabilizes the TTR tetramer results in TTR normalized clearance, thus increasing the protein plasma levels. In turn, stabilized TTR binds more strongly to Aß peptide, avoiding its aggregation. Our results represent a step forward to the understanding of the mechanism underlying TTR protection in AD and highlight the possibility of using TTR stabilization as a therapeutic target in AD.

Spatial accumulation of flood-driven riverside litter in two Northern Atlantic Rivers.

The escalation of litter accumulation in aquatic environments is recognized as an emerging global concern. Although rivers represent the main conduits for land-based waste into the oceans, the spatial dynamics of litter accumulation in these systems remain poorly investigated, especially after hydro-climatic extreme events. Floods have been identified as major drivers of litter mobilization, including macroplastics, within rivers. However, predicting flood-induced litter accumulation along riverbanks is complex due to the cumulative interplay of multiple environmental (geomorphological and riparian) and anthropogenic factors. Using empirical data collected from 14 stream reaches in two Northern Atlantic rivers in Portugal, our study evaluates which factors, among geomorphological, riparian, and anthropogenic descriptors, best drive riverside litter accumulation after floods. Taking into account the longitudinal gradient and the spatial heterogeneity of the studied reaches, our study enhances how the accumulation and characteristics (type, size) of riverside litter vary across a rural-urban continuum. Our model reveals that the combination of the human population density and the stream slope at river reach showed the highest explanatory power for the accumulation of riverside litter. Our findings indicate that litter tends to be retained close to the source, even under flood conditions. We also found that the structure of riparian vegetation showed low explanatory power for litter accumulation. However, riparian trapping could be influenced by litter input (density and type) which varies with anthropogenic activities. This work highlights the importance of gathering field data to identify critical areas of riverside litter accumulation within river basins. Our findings can further support environmental managers in designing and implementing effective cleanup campaigns and implementing plastic recovery strategies at specific areas. Nevertheless, it is crucial to enhance coordinated efforts across the entire value chain to reduce plastic pollution, promote innovative approaches for plastic litter valorization, and establish effective prevention pathways.

Bioaccessibility and bioavailability of essential and potentially toxic trace elements in potato cultivars: A comprehensive nutritional evaluation.

Among the most consumed foods in the world is potato, which occupies the first place as a non-grain commodity, demonstrating the importance of its assessment concerning the population's food safety. In this study, the nutrients Ca, Mg, K, P, Cu, Mn, Fe, and Zn and the potentially toxic trace elements Cd, Cr, and Pb were evaluated considering their total contents, bioaccessible and bioavailable fractions in different potato cultivars, in an unpublished approach in the literature. The in vitro standard gastrointestinal digestion method (INFOGEST) and a model of the intestinal epithelial barrier using the Caco-2 cell line were applied for investigate the presence of metals in potato. For the macroelements, the bioaccessibility (% w/w) varied in the ranges: K (57-72 %), P (59-76 %), Mg (83-103 %), and Ca (30-123 %), whereas for the microelements were: Cu (27-74 %) and Mn (4.22-12.02, 60-119 %). The potentially of trace toxic elements, Cd and Pb, were found in 75 % of the samples, however, all the concentration values were below the maximum levels allowed of 0.10 µg/g. Chromium was determined only in potato peels and has no maximum established level. The bioaccessible and bioavailable fractions of Cd, Cr, and Pb were below the limits of quantification of the spectrometric methods (LOQ - µg/L: 0.063 Cd, 0.65 Cr, and 0.44 Pb). The potato samples were considered safe for consumption regarding the presence of potentially toxic trace elements, with a remarkable nutritional contribution.

Biochemical changes in the liver and gill of Cathorops spixii collected seasonally in two Brazilian estuaries under varying influences of anthropogenic activities.

In order to understand environmental health by the use of a bioindicator species in estuaries, biochemical responses observed in the catfish Cathorops spixii such as catalase (CAT), glutathione-S-transferase (GST), lipid peroxidation (LPO) and acetylcholinesterase (AChE) were evaluated in liver and muscle. Furthermore, histological changes were also verified in liver and gills preparations. Fish were collected in three sites of the Santos-São Vicente estuary located at São Paulo (Brazil), subjected to varying levels of inputs of pollutants. For a reference site, specimens were sampled at Cananéia estuary at southern coast of São Paulo, a region with low anthropogenic influence. In general, no significant seasonal differences in antioxidant enzymes and lipid peroxidation responses were found in the organisms from the Cananéia estuary. However, in the polluted estuary (Santos-São Vicente), biochemical responses were observed by increases in GST hydroperoxides and decreases in AChE activities in the summer. Inhibition of AChE expression in fish from different areas of the Santos-São Vicente estuary in the summer was also found and can indicate neurotoxic effects in these organisms. Histopathological observation of gill and liver showed severe lesions, such as lamellar fusion and necrosis.

Risks of waterborne copper exposure to a cultivated freshwater Neotropical catfish (Rhamdia quelen).

As it is the case in all animal food production systems, it is often necessary to treat farmed fish for diseases and parasites. Quite frequently, fish farmers still rely on the aggressive use of copper to control bacterial infections and infestations by ecto-parasites, and to manage the spread of diseases. The susceptibility of the neotropical fish Rhamdia quelen to copper was here evaluated at different waterborne copper concentrations (2, 7 or 11 µg Cu L(-1)) for 96 h, through a multi biomarkers approach. Liver histopathological findings revealed leukocyte infiltration, hepatocyte vacuolization and areas of necrosis, causing raised levels of lesions upon exposure to 7 and 11 µg Cu L(-1). Decreased occurrence of free melano-macrophages and increased densities of melano-macrophage centers were noted upon exposure to 11 µg Cu L(-1). Gills showed damages on their secondary lamellae already at 2 µg Cu L(-1); hypertrophy and loss of the microridges of pavement cells at 7 and 11 µg L(-1), and increased in chloride cell (CC) apical surface area (4.9-fold) and in CC density (1.5-fold) at 11 µg Cu L(-1). In the liver, catalase (CAT), glutathione peroxidase activities (GPx) and glutathione concentration (GSH) remained unchanged, compared to the control group. However, there was inhibition of 7-ethoxyresorufin-O-deethylase (EROD) at all copper concentrations tested. Glutathione reductase activity (GR) was reduced and levels of lipid peroxidation (LPO) were increased at 11 µg Cu L(-1). Glutathione S-transferase activity (GST) at 7 µg Cu L(-1) and superoxide dismutase activity (SOD) at both 7 and 11 µg Cu L(-1) were reduced. However, copper exposure did not alter brain and muscle acetylcholinesterase (AChE) activity. Osmoregulatory function was also disturbed, in agreement with the above-mentioned changes noted in the gills, as detected by plasma osmolality reduction in the group exposed to 11 µg Cu L(-1), and plasma chloride reduction at 2 µg Cu L(-1). These concentrations also, coherently, lead to inhibition of branchial carbonic anhydrase activity. In the kidney, increased carbonic anhydrase activity was measured in the groups exposed to 2 and 7 µg Cu L(-1). When these effects are compared to data available in the literature for other freshwater fish, also for 96 h of exposure, R. quelen appears as a relatively sensitive species. In addition, the concentrations employed here were quite low in comparison to levels used for disease control in real culture practices (ranging from 4 µg Cu L(-1) used against bacteria to 6000 µg Cu L(-1) against fungal infections). We can conclude that the concentrations frequently employed in aquaculture are in fact not safe enough for this species. Such data are essential for the questioning and establishment of new policies to the sector.

Effects of the herbicide atrazine in neotropical catfish (Rhamdia quelen).

The exposure to a world-wide used herbicide atrazine (ATZ) (96h exposure to 2, 10, and 100µgL(-1)), was investigated on the freshwater fish Rhamdia quelen through a multi biomarker approach. Liver histopathology revealed leukocyte infiltration, hepatocyte vacuolization like steatosis and necrosis areas, leading to raised lesion index levels in all tested concentrations. The increase of free melanomacrophage numbers was observed. Gill filaments revealed considerable loss of the microridges on pavement cells at 10 and 100µgL(-1) of ATZ, and a significantly increased of chloride cell (CC) number and density on apical surface area at 100µgL(-1) of ATZ. CAT, GST, GPx, and GR activities were inhibited by all tested concentrations. GSH levels were reduced in individuals exposed to 100µgL(-1). Osmoregulatory function was also disturbed. We observed an increase of plasma magnesium concentrations at 10µgL(-1). Additionally the inhibition of branchial carbonic anhydrase activity was observed at 100µgL(-1). In the kidney, carbonic anhydrase activity decreased only in the group exposed to 2µgL(-1). These results suggest that ATZ, represents a potential ecotoxicological hazard and can be hepatotoxic and nephrotoxic even low concentrations. The current study was the first to show the nephrotoxic effect of ATZ in fish. Besides, in Brazil, the environmental protection agency (CONAMA) establishes that the maximum allowed level of dissolved ATZ in water is 2µgL(-1), but the present results showed that this concentration may cause histopathological, biochemical and physiological changes in R. quelen.

Earlier biomarkers in fish evidencing stress responses to metal and organic pollution along the Doce River Basin.

The Doce River Basin (DRB) represents a well-described watershed in terms of contamination by metals, especially after a major environmental disaster of a mining tailing dam failure. Despite the massive mortality of the ichthyofauna, very few studies addressed the risks to the health of wild fish exposed to complex mixtures of pollutants from multiple sources. The present study proposed to investigate earlier responses of fish for assessing the impacts of multiple sources of pollution, considering: different niches of fish and target organs; and the influence of seasonality, associated with their probable sources of pollution. To achieve that, fish were collected along the DRB, and biomarkers responses were assessed in target organs and correlated with the levels of inorganic and organic contaminants. As one of the most prominent responses, fishes from the Upper DRB showed the highest expression of the metallothionein and oxidative stress parameters which were related to the higher levels of metals in this region due to the proximity of mining activities. On the other hand, higher levels of DNA damage and increased AChE activity from fish sampled in the Mid and Lower DRB were more associated with organic contaminants, from other sources of pollution than mining residues. The integrated biomarker responses also revealed seasonal variations, with higher values in fishes from the dry season, and pelagic fish showing greater variation within the seasons. The multivariate analysis integrating suitable biomarkers with chemical data represented an adequate strategy for assessing the ecological risks in the DRB, allowing the identification of distinct spatio-temporal impacts from multiple sources of contaminants. The continued exposure of the ichthyofauna representing future risks reinforces the need for ecological restoration and the protection of the fauna from the Doce River.

Bioaccumulation and related effects of PCBs and organochlorinated pesticides in freshwater fish Hypostomus commersoni.

Few studies have investigated the bioaccumulation of persistent organic pollutants (POPs) in Brazilian native freshwater fish. In order to evaluate the bioavailability, potential risk to human exposure and the effects of POPs in the fish Hypostomus commersoni, muscle and liver samples of thirteen specimens were collected in a lake located in the city of Ponta Grossa (Parana State, Southern Brazil). Also, the liver and gills were considered for histopathological studies, and oxidative stress was investigated in the liver. Expressive concentrations of POPs were observed in the liver and muscle, with a total of 427 ± 78.7 and 69.2 ± 18.1 ng g(-1) dry weights of polychlorinated biphenyls (PCBs), respectively. Negative correlations between the concentration of several POPs and glutathione S-transferase and glucose-6-phosphate dehydrogenase were found. Otherwise, the cholinesterase activity in the muscle and brain presented positive correlations with the concentration of POPs. The hepatic bioaccumulation of some banned pesticides like aldrin, dieldrin and DDT was associated with various histopathological findings in the liver and gills. Necrotic areas, fibrosis, leukocyte infiltration, and the absence of macrophage centers were observed in the liver, indicating both chronic exposure and immunological suppression. Neoplasic changes were observed in the gills, confirming the carcinogenic potential reported for some of the investigated pollutants. The current work was the first to study the bioaccumulation of POPs in H. commersoni, an important species in ecological aspects and as a vehicle to human exposure to PCBs and organochlorine pesticides (OCPs).

Alterations in morphometric and organosomatic indices and histopathological analyses indicative of environmental contamination in Mullet, Mugil liza, from Southeastern Brazil.

Mullet (Mugil liza) were sampled in five different areas along the Guanabara Bay, southeastern Brazil, classified as non-contaminated, moderately contaminated and contaminated. Morphometric (Fulton condition factor, relative condition factor and weight to length scaling coefficient) and organosomatic (hepatosomatic index) indices of environmental stress were analysed. Fish from the differentially contaminated areas show statistically different Fulton and relative condition factors and hepatosomatic indices, but not the weight to length scaling coefficient. The Kn and the FCF followed the same trend, with fish from São Gonçalo (1.07 ± 0.04 and 0.89 ± 0.03), Itaipu (0.84 ± 0.01 and 0.86 ± 0.01) and the Rodrigo de Freitas Lagoon (1.03 ± 0.01 and 0.87 ± 0.20) showing higher FCFs than fish from Magé (0.96 ± 0.01 and 0.81 ± 0.01). Fish from Itaipu showed significantly higher HSI values than the other sampling sites (1.68 ± 0.07), with fish from Olaria and Ipiranga showing the lowest (1.56 ± 0.12 and 1.60 ± 0.07, respectively).

Tissue distribution and depuration kinetics of waterborne 14C-labeled light PAHs in mummichog (Fundulus heteroclitus).

Light polycyclic aromatic hydrocarbons (PAHs) of petrogenic origin are commonly found in estuaries and coastal areas. Though they are known to be toxic to fish, little is known about their uptake and tissue distribution. This paper reports on the results of a study on uptake, elimination, and tissue distribution of three waterborne 14C-labeled PAHs in the mummichog, Fundulus heteroclitus, using whole-body autoradiography. After a 24 h exposure to 1 µCi·L(-1) of 14C-naphthalene, 14C-1-naphthol, and 14C-phenanthrene, fish were transferred to clean water and tissue distribution examined after 0, 1, 3, 7, 14, and 21 days of depuration. All compounds were readily accumulated by fish and were also rapidly eliminated (t0.5 range=1.1 to 3.0 days). Most of the radioactivity in naphthalene- and phenanthrene-treated fish was found in gall bladder≫liver>intestinal lumen. In naphthol-exposed fish, an important labeling of some brain areas was observed. Brain of naphthalene-exposed fish was also labeled after 24 h depuration, indicating that exposure to naphthalene may result in metabolite accumulation in the brain. This is the first study showing that naphthalene, naphthol, and/or unidentified metabolite(s) can accumulate in brain tissues, which may impair normal brain function.

Subchronic effects of dipyrone on the fish species Rhamdia quelen.

The use of the non-steroidal anti-inflammatory drugs such as dipyrone is so widespread that this drug and its metabolites have been detected in effluents and surface water. This study aimed to evaluate the potential toxic effects of dipyrone on the aquatic environment, using a native fish species, Rhamdia quelen. Fish were exposed to three concentrations of dipyrone, 0.5, 5 and 50 µg/L, in the water for 15 days, and hematological, biochemical, genetic and morphological biomarkers were evaluated. The glutathione S-transferase activity decreased in the highest concentration in relation to the control group. In addition, hematocrit, red blood cells and thrombocyte counts were decreased in all three exposed groups in relation to the control group. The comet assay showed DNA damage at the lowest concentration of dipyrone and significant kidney damage. Those results suggest that a constant exposure of aquatic organisms to dipyrone presents potential toxic effects.

Evaluation of waterborne exposure to oil spill 5 years after an accident in Southern Brazil.

Fish (Astyanax sp.) were exposed to water samples from the Arroio Saldanha, locality of an oil spill, and the Barigui River (upstream and downstream of the confluence of the river and Arroio Saldanha), Brazil. Histopathological and biochemical biomarkers, as acetylcholinesterase (AchE), ethoxyresorufin-O-deethylase (EROD), catalase (CAT), glutathione-S-transferase (GST) activities, lipid peroxidation (LPO) levels, and amounts of polynuclear aromatic hydrocarbon residues (PAHs) in bile were evaluated. PAHs, metals, and surfactants were investigated in the water samples. CAT and GST activities increased in the Arroio Saldanha sample, whereas CAT activity and LPO levels were increased in the upstream and downstream sites. The results suggested a toxic action of the free radicals and disturbance of the antioxidant defense mechanisms. However, the EROD and AchE activities were not affected. Histopathology studies showed severe lesions. The oil is still bioavailable to biota, moreover, other pollution sources continue to affect the water in the Barigui River.

Genotoxic evaluation of different doses of inorganic lead (PbII) in Hoplias malabaricus.

Different genetic biomarkers have been used to evaluate the pollution effects of mutagenic agents such as metals and also a great variety of chemicals delivered on the environment by human activities. This way, the aim of the present report was to evaluate the effects of inorganic lead in fishes through the frequency of piscine micronuclei and nuclear morphological alterations in peripheral cells, chromosomal aberration frequency and comet assays in blood and kidney cells. Specimens of Hoplias malabaricus received different doses of lead by intra-peritoneal injections at time of 96 h. There was not a significant difference between control and treated groups for the piscine micronucleus and chromosomal aberration assays. In the comet assays there was a significant difference between control and contaminated groups. However, a significant difference between the applied doses was not observed. The results obtained with the comet assays also show that blood presented a higher sensibility than the kidney tissue, possibly due to the acute contamination. Although the results showed the genotoxic potential of lead at the 21 and 63 microg Pb(2 + )/g doses for both tissues, the lowest dose is considered more appropriate for future bioassays.

An assessment of acute biomarker responses in the demersal catfish Cathorops spixii after the Vicuña oil spill in a harbour estuarine area in Southern Brazil.

The Vicuña oil tanker exploded in Paranaguá Bay (South of Brazil), during methanol unloading operations in front of Paranaguá Harbour, on November 15th, 2004, releasing a large amount of bunker oil and methanol. Two weeks after the accident, the acute effects of the Vicuña Oil Spill (VOS) were evaluated in the demersal catfish Cathorops spixii, comparing a contaminated (at the spill site) and a reference site inside the Bay. Data were compared to previous measurements, taken before the accident, in the same species, from the same sites. The physiological biomarkers were the ones that best reflected acute effects of the spill: plasma osmolality, chloride, calcium, magnesium, and potassium. Morphological (liver and gill histopathology) and genetic (piscine micronucleus and DNA strand breaks) biomarkers revealed that damage was already present in fishes from both reference and contaminated sites inside the Bay. Thus, the reference site is not devoid of contamination, as water circulation tends to spread the contaminants released into other areas of the Bay. Acute field surveys of oil spill effects in harbour areas with a long history of contamination should thus be viewed with caution, and whenever possible previous evaluations should be considered for proper appraisal of biomarker sensitivity, especially in mobile bioindicators such as fish.

Toxic effects of DDT and methyl mercury on the hepatocytes from Hoplias malabaricus.

Here, we examined the impact of dichlorodiphenyltrichloroethane (DDT) and monomethyl mercury (MeHg) on the redox milieu and survival of hepatocytes from Hoplias malabaricus (traíra). After isolation and attachment of cells, we established one control and four treatments: DDT (50nM of DDT), MeHg I (0.25microM of MeHg), MeHg II (2.5microM of MeHg) and DDT * MeHg I (combination of 50nM of DDT and 0.25microM of MeHg). After four days the exposed hepatocytes presented significantly increased damage in lipids (all treatments), proteins (DDT * MeHg I and MeHg II) and reduced cell viability (all treatments). Also the antioxidant enzymes catalase, glucose-6-phosphate dehydrogenase (G6PDH), glutathione reductase and superoxide dismutase were affected. The current data showed that despite of some protective responses, the increased disturbs on membrane lipids and proteins, increased hydrogen peroxide levels, and decreased glutathione concentration and cell viability strongly indicate oxidative stress as the reason of hepatotoxicity due to DDT and MeHg exposure. In addition, DDT and MeHg together had greater effect than alone when G6PDH and glutathione-S-transferase activities and lipids damage were considered. These findings are indicative of hepatotoxicity occurring at realistic concentrations of DDT and MeHg found in Amazonian fish tissues.

The immune response of peritoneal macrophages due to exposure to inorganic lead in the house mouse Mus musculus.

Peritoneal macrophages from the house mouse (Mus musculus) were exposed to variable lead (Pb) concentrations (0.2, 2, 20 and 40 microM) to better understand lead cytotoxicity and its damage to the immune response. Phagocytes were exposed to 20 and 40 microM Pb for 72 h, and macrophages were exposed at lower concentrations (0.2, 2 and 20 microM Pb) for 24h and 72 h. Dysfunctions in macrophage immune activity were examined by measuring phagocytic activity, nitric oxide production, endosomal/lysosomal stability and cell adhesion. Lead affected all macrophage functions, even at low concentrations, by reducing the phagocytic index, nitric oxide production, endosomal/lysosomal system stability and cell adhesion, and upregulating the antioxidant enzymatic activity of catalase. We demonstrate that lead affects the redox status of the cells and suggest that the immunomodulatory effects at low dosages on mouse macrophages reduces their ability to protect the host against infectious agents.

Bioaccumulation of chlorinated pesticides and PCBs in the tropical freshwater fish Hoplias malabaricus: histopathological, physiological, and immunological findings.

For assessing the impact of chlorinated compounds, such as organochlorine pesticides, polychlorinated biphenyls, chlorotriazines (atrazine, simazine), and chlorinated phenylureas (diuron), on the Ponta Grossa lake South of Brazil, ten freshwater trahira fish (Hoplias malabaricus) were collected in October 2005. The contamination status was evaluated by the energy budget and various histopathological markers. The results showed detectable amounts of persistent organic pollutants (POPs) in the liver and muscle; the bioaccumulation was higher in the liver than in the muscle. The presence of some banned pesticides, such as hexachlorobenzene and dichlorodiphenyltrichloroethane, in the liver suggests an acute exposure to these compounds. Some physiological disturbances and morphological damages found in the liver of H. malabaricus were associated with chlorinated-compound bioaccumulation. The most important alterations in the liver were lesions such as fibrosis, large necrosis area, leukocyte infiltration, and the absence of melanomacrophages (MM). Individuals containing higher concentrations of pesticides, such as aldrin, alachlor, and dichloroaniline (a metabolite of diuron), showed the nonoccurrence of MM in the liver. These data suggest an immunosuppression in the individuals from Ponta Grossa Lake after exposure to POPs. According to the present data, the POPs found in the studied site are bioavailable, induce severe damages in target organs such as the liver, and can disturb the immune system of the trahira. This is the first study of POPs in the Paraná state, and one among the few studies in the south of Brazil. The present data suggest and motivate further chemical and biomonitoring studies in freshwater ecosystems in the south of Brazil.

Bioaccumulation of polychlorinated biphenyls in the eel (Anguilla anguilla) at the Camargue Nature Reserve - France.

Fish consumption is a potential source of human exposure to pollutants. Here, we study residue levels of PCBs in the eel, Anguilla anguilla, from the Nature Camargue Reserve in southern France. Chromatographic analysis (GC-ECD) found seventy identifiable congeners, among which, 10 are considered as dioxin-like PCBs, such as the non-ortho PCB 81 and the mono-ortho chlorobiphenyls PCB105, 114, 118, 123, 156, 157, 167, 170, 180. Toxic Equivalents (TEQ, WHO 2005 TEF-Toxic Equivalent Factors) varied among sites with a maximum in eels from Mornès (29.6pgg(-1) dry weight). Indicator PCBs (28, 52, 101, 118, 138, 153 and 180) were 22% and 29% of the total PCBs in livers and muscles respectively. Greater homogeneous bioaccumulation in muscle than that in liver suggests an increase risk for humans due to fish consumption.