Compounds In Aquatic Ecosystems Research Articles

Enrichment of Water Bodies with Phenolic Compounds Released from Betula and Pinus Pollen in Surface Water.

Betula and Pinus pollen, which are dispersed in natural surface waters, release biologically active compounds into the water bodies. This study aims to evaluate variations in the distribution and composition of phenolic compounds in suspended particles in natural water bodies during pollen spreading. Samples taken from water bodies of different trophic levels were analyzed by microscopy, UV/VIS spectroscopy, HPTLC, and HPLC/DAD. The study revealed that the total phenolic content in water-suspended particles varied from 3.0 mg/g to 11.0 mg/g during Betula and Pinus pollen spreading. It was also observed that the surface water of dystrophic natural lakes had a higher content of phenolic compounds than the eutrophic, hypereutrophic, and mesotrophic water bodies. Chlorogenic, trans-ferulic, vanillin, and 3,4-dihydroxybenzoic acids were frequently detected in the surface water samples. Experimental measurements have shown variations in the release of phenolic compounds from Betula pollen into water (p < 0.05). After the exhibition of pollen, the distilled water predominantly contained bioactive chlorogenic acid. Further in situ investigations are necessary to gain a more comprehensive understanding of the function of phenolic compounds in aquatic ecosystems. The exploration of the release of bioactive compounds from pollen could provide valuable insights into the potential nutritional value of pollen as a nutrient source for aquaculture.

Phenolic compounds in the freshwater environment in South Korea: Occurrence and tissue-specific distribution

In this study, we investigated the occurrence and distribution of phenolic compounds, including phenol, cresols, chlorophenols, nitrophenol, and bromophenols, in freshwater environments. We also focused on phenolic compounds in crucian carp (Carassius auratus) tissues, specifically the muscle, gills, brain, blood, liver, and gonads, to assess their potential bioaccumulation in fish and human health risks. Phenolic compounds were found to be widespread in various freshwater environments throughout South Korea. Phenol was predominant in all matrices, with median concentrations of 57.0 ng/L in freshwater, 54.3 ng/g dry weight (dw) in sediment, and ranging from 71 ng/g wet weight (ww) to 621 ng/g ww in crucian carp tissues. Cresols were the second most dominant compound, with m-cresol exhibiting the highest prevalence. Most of the compounds detected in crucian carp samples were also detected in freshwater and sediment, whereas pentachlorophenol and 2,4,6-tribromophenol were exclusively detected in crucian carp tissues. A high bioaccumulation potential in the liver was observed for most phenolic compounds [median log bioconcentration factor (BCF): 3.2–3.7]. Interestingly, only m-cresol showed high bioaccumulation potential in the gills (median log BCF: 3.1). The estimated daily intake of phenolic compounds suggested that it does not pose an immediate concern for human exposure owing to crucian carp consumption. These findings enhance our understanding of the exposure status, distribution, and bioaccumulation potency of phenolic compounds in aquatic ecosystems and emphasize the importance of ongoing monitoring and risk assessment efforts.

Environmentally relevant concentrations of triclocarban affect behaviour, learning, and brain gene expression in fish

Many chemicals spilled in aquatic ecosystems can interfere with cognitive abilities and brain functions that control fitness-related behaviour. Hence, their harmful potential may be substantially underestimated. Triclocarban (TCC), one of the most common aquatic contaminants, is known to disrupt hormonal activity, but the consequences of this action on behaviour and its underlying cognitive mechanisms are unclear. We tried to fill this knowledge gap by analysing behaviour, cognitive abilities, and brain gene expression in zebrafish larvae exposed to TCC sublethal concentrations. TCC exposure substantially decreased exploratory behaviour and response to stimulation, while it increased sociability. Additionally, TCC reduced the cognitive performance of zebrafish in a habituation learning task. In the brain of TCC-exposed zebrafish, we found upregulation of c-fos, a gene involved in neural activity, and downregulation of bdnf, a gene that influences behavioural and cognitive traits such as activity, learning, and memory. Overall, our experiments highlight consistent effects of non-lethal TCC concentrations on behaviour, cognitive abilities, and brain functioning in a teleost fish, suggesting critical fitness consequences of these compounds in aquatic ecosystems as well as the potential to affect human health.

Exploiting fungi in bioremediation for cleaning-up emerging pollutants in aquatic ecosystems

Aquatic pollution negatively affects water bodies, marine ecosystems, public health, and economy. Restoration of contaminated habitats has attracted global interest since protecting the health of marine ecosystems is crucial. Bioremediation is a cost-effective and eco-friendly way of transforming hazardous, resistant contaminants into environmentally benign products using diverse biological treatments. Because of their robust morphology and broad metabolic capabilities, fungi play an important role in bioremediation. This review summarizes the features employed by aquatic fungi for detoxification and subsequent bioremediation of different toxic and recalcitrant compounds in aquatic ecosystems. It also details how mycoremediation may convert chemically-suspended matters, microbial, nutritional, and oxygen-depleting aquatic contaminants into ecologically less hazardous products using multiple modes of action. Mycoremediation can also be considered in future research studies on aquatic, including marine, ecosystems as a possible tool for sustainable management, providing a foundation for selecting and utilizing fungi either independently or in microbial consortia.

Heart rate and behavioral responses in three phylogenetically distant aquatic model organisms exposed to environmental concentrations of carbaryl and fenitrothion

Carbaryl and fenitrothion are two insecticides sharing a common mode of action, the inhibition of the acetylcholinesterase (AChE) activity. Their use is now regulated or banned in different countries, and the environmental levels of both compounds in aquatic ecosystems have decreased to the range of pg/L to ng/L. As these concentrations are below the non-observed-adverse-effect-concentrations (NOAEC) for AChE inhibition reported for both compounds in aquatic organisms, there is a general agreement that the current levels of these two chemicals are safe for aquatic organisms. In this study we have exposed zebrafish, Japanese medaka and Daphnia magna to concentrations of carbaryl and fenitrothion under their NOAECs for 24-h, and the effects on heart rate (HR), basal locomotor activity (BLA), visual motor response (VMR), startle response (SR) and its habituation have been evaluated. Both pesticides increased the HR in the three selected model organisms, although the intensity of this effect was chemical-, concentration- and organism-dependent. The exposure to both pesticides also led to a decrease in BLA and an increase in VMR in all three species, although this effect was only significant in zebrafish larvae. For SR and its habituation, the response profile was more species- and concentration-specific. The results presented in this manuscript demonstrate that concentrations of carbaryl and fenitrothion well below their respective NOAECs induce tachycardia and the impairment of ecologically relevant behaviors in phylogenetically distinct aquatic model organisms, both vertebrates and invertebrates, emphasizing the need to include this range of concentrations in the environmental risk assessment.

Development of Analytical Procedure for the Determination of 17β-Testosterone, 11-Ketotestosterone and 17β-Estradiol in the Sea Trout (Salmo trutta L.) Gonads

Steroid hormones, such as 17β-testosterone, 11-ketotestorenone and 17β-estradiol, play an essential role not only in reproductive function but also are potential biomarkers of numerous additional functions in teleost fish. The presence of endocrine disruptor compounds in aquatic ecosystems has raised concern about their effect on hormone levels in fish target organs. Since hormones are present in very low concentrations in biological material, their determination still remains a challenge. A new analytical procedure has been developed to determine 17β-testosterone, 11-ketotestosterone and 17β-estradiol in the sea trout female and male gonads by liquid chromatography-tandem mass spectrometry (LC-MS/MS) system equipped with an ESI source operating in both positive and negative mode. Chromatographic separation of analytes was accomplished in Poroshell 120 EC-C18 (150 mm × 2.1 mm, 2.7 µm) column under isocratic elution conditions. The mobile phase consisted of acetonitrile, methanol and water (20:50:30/v/v/v) at a flow rate of 0.2 mL/min. Analytes were extracted from the gonad matrix with ethyl acetate, and co-extractives impurities were successfully removed by QuEChERS (quick, easy, cheap, effective, rugged and safe) method. The procedure was validated with good sensitivity, linearity, accuracy, and precision. Limits of quantifications were from 0.15 to 0.75 ng/g, linearity was obtained with correlation coefficient R &gt; 0.99, accuracy was from 94.0 to 109.5%, precision expressed as RSD ranged from 1.7 to 27.2% (repeatability) and from 2.2 to 37.1% (reproducibility). Finally, the method was applied to determining 17β-testosterone, 11-ketotestosterone and 17β-estradiol in real samples of the female and male sea trout gonads, 8 and 22 samples, respectively.

Teratogenicity of retinoids detected in surface waters in zebrafish embryos and its predictability by in vitro assays.

Retinoids are newly detected compounds in aquatic ecosystems associated with cyanobacterial water blooms. Their potential health risks are only scarcely described despite numerous detections of all-trans retinoic acid (ATRA) and its derivatives in the environment. Besides the known teratogen ATRA there is only little or no information about their potency and namely their effects in vivo. We characterize ATRA and 8 other retinoids reported to occur in the environment for their bioactivity and teratogenicity using four in vitro reporter gene assays and zebrafish (Danio rerio) embryotoxicity assay. Our results document the ability of these compounds to interfere with retinoid signalling and cause teratogenicity at environmentally relevant levels with EC50 values at nM (hundreds of ng/L) levels and teratogenic indexes ranging from 2.8 (9cis retinoic acid) to 15.8 (retinal). The relative potency of individual compounds for teratogenicity ranged from 0.059 (retinal) to 0.96 (5,6-epoxy ATRA) when compared to ATRA. An environmentally relevant mixture of retinoids was tested showing good predictability of teratogenicity from the in vitro activities and additive toxicity of the mixture. The high teratogenicity of the newly described compounds associated with cyanobacteria presents a concern for developmental stages due to high conservation of the retinoid signalling across vertebrates.

Effects of nitrite exposure on metamorphosis and skeletal development of Bufo gargarizans.

Nitrite, as a part of nitrogen cycle, is one of the most common toxic compounds in aquatic ecosystems. Since skeletal development is an essential process during amphibian metamorphosis, exposure of larval amphibians to nitrite might disrupt skeletal development. To evaluate whether nitrite affects skeletal development of amphibian larvae, Bufo gargarizans larvae at Gs26 were exposed to 10, 100, 500 and 1000μg/L nitrite-nitrogen (NO2-N) in the present study. The metamorphosis rate, body weight, body length, forelimb length and hindlimb length of B. gargarizans exposed to NO2-N were decreased. The microscopic structures of thyroid gland were altered under NO2-N exposure at Gs42. The skeletal lengths of the humerus, femur and fibulare of tadpole at Gs42 were significantly reduced under 100, 500 and 1000μg/L NO2-N treatment groups, and the lengths of humerus, tibia-fibula and tibiale of tadpole at Gs46 were significantly reduced under 1000μg/L NO2-N treatment groups. In addition, the expression levels of thyroid hormone (TH) and endochondral ossification-related genes of tadpoles at Gs42 and Gs46 were tested by qRT-PCR. Overall, NO2-N exposure could affect the expressions of these genes and then may influence the activity and function of thyroid gland, further disturbing the amphibian metamorphosis and skeletal development of amphibian larvae.

Suspect screening of pharmaceuticals in fish livers based on QuEChERS extraction coupled with high resolution mass spectrometry

The presence of pharmaceuticals and personal care products (PPCPs) in aquatic environments is of increasing concern due to the presence of residues in fish and aquatic organisms, and emerging antibiotic resistance. Wastewater release is an important contributor to the presence of these compounds in aquatic ecosystems, where they may accumulate in food webs. The traditional environmental surveillance approach relies on the targeted analysis of specific compounds, but more suspect screening methods have been developed recently to allow for the identification of a variety of contaminants. In this study, a method based on QuEChERS extraction – using acetonitrile/water mixture as solvent and PSA/C18 for sample clean-up – was applied to identify pharmaceuticals and their metabolites in fish livers. Both target and suspect screening workflows were used and fish were sampled upstream and downstream of wastewater treatment plants from the Scioto River, Ohio (USA). The method performed well in terms of extraction of some target PPCPs, with recoveries generally above 90%, good repeatability (<20%), and linearity. Based on target analysis, lincomycin and sulfamethoxazole were two antibiotics identified in fish livers at average concentrations of 30.3 and 25.6 ng g−1 fresh weight, respectively. Using suspect screening, another antibiotic, azithromycin and an antidepressant metabolite, erythrohydrobupropion were identified (average concentrations: 27.8 and 13.8 ng g−1, respectively). The latter, reported, to the best of our knowledge, for the first time in fish livers, was also found at higher concentrations in fish livers sampled downstream vs. upstream. The higher frequency of detection for azithromycin in benthic feeding fish species (63%) as well as clusters identified between different foraging groups suggest that foraging behavior may be an important mechanism in the bioaccumulation of PPCPs. This study shows how suspect screening is effective in identifying new contaminants in fish livers, notably using differential analysis among different spatially distributed samples.

Natural daily patterns in fish behaviour may confound results of ecotoxicological testing.

Low doses of neuroactive chemicals end up in the environment and disrupt behaviour of non-target organisms. Although a whole range of studies have documented pollutant-induced changes in behaviour, natural daily variability in behaviour is rarely taken into account. This is surprising because biological rhythms may affect the outcome of experiments, are adaptive and are expected to be sensitive to neurochemical exposure. Here, we exploit daily behavioural variation in the fish model Nothobranchius furzeri to examine if behavioural effects of chronic exposure (74 days) to an environmentally relevant level (28ng/L) of the neurochemical fluoxetine depend on the time of day. Fluoxetine exposure induced an increase in anxiety-related behaviour that was slightly more pronounced in the evening compared to the morning. Moreover, open-field locomotor activity was disrupted and daily patterns in activity lifted upon exposure to the compound. These results imply that short-term behavioural variability should be considered both to standardise ecological risk assessment of neuroactive chemicals as well as to better understand the environmental impact of such compounds in aquatic ecosystems.

Carbon and nitrogen deposition on the surface of marginal sediments under different land use systems along the Paraopeba river basin (Minas Gerais, State)

The knowledge of the contents of organic compounds in aquatic ecosystems is of great importance, since the dissolved organic matter represents a dynamic component in the interaction between geospheres. The objective of this study was to evaluate the levels of carbon, nitrogen, and carbon-to-nitrogen ratio in the marginal sediments and the carbon content in the waters along the Paraopeba river basin (MG). The samples were collected in five locations (Jeceaba, Brumadinho, Fortuna de Minas, Florestal, and Três Marias) corresponding to the high, medium, and low river segments. The carbon content was determined by the Walkley &amp; Black method and the nitrogen content by the Kjeldahl method. The carbon content ranges from 4.75 to 5.97 g kg-1. Nitrogen ranged from 0.73 to 1.08 g kg-1. Finally, the carbon-to-nitrogen ratio varied from 5.15 to 21.25. The carbon content in the water samples ranged from 0 to 0.25 g L-1. As the values ​​of dissolved organic carbon were very low or even zero, the nitrogen content and the carbon-to-nitrogen ratio were not determined. There was a negative and a positive correlation with the aluminum content (r = -0.70 and r = 0.74, respectively) indicating possible contamination by heavy metals. Therefore, the levels of carbon, nitrogen, and the carbon-to-nitrogen ratio were sensitive indicators of changes in the aquatic ecosystem.

Diclofenac and caffeine inhibit hepatic antioxidant enzymes in the freshwater fish Astyanax altiparanae (Teleostei: Characiformes)

Although concentrations of pharmaceutical compounds in aquatic ecosystems are low, they can cause toxic effects on organisms. The aim of this study was to evaluate the effects of diclofenac (DCF), a non-steroidal anti-inflammatory drug, and caffeine (CAF), a central nervous system stimulant, both alone or combined, in Astyanax altiparanae males under acute exposure (96 h), measuring neurotoxicity biomarkers, antioxidant response and damage at biochemical and cellular levels. DCF concentration in water, separated and combined, was 3.08 mg L−1 and that of CAF was 9.59 mg L−1. To assess neurotoxicity, brain and muscle acetylcholinesterase (AChE) activities were measured. To evaluate oxidative stress, the enzymatic activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) and glutathione S-transferase (GST), as well as lipoperoxidation (LPO), were analyzed in liver and gills. Activity of hepatic cyclooxygenase (COX) was also evaluated. Genotoxicity was assessed in blood using comet assay and micronucleus test, as well as nuclear abnormalities. DCF and CAF, alone or combined, had neither effect on AChE activity, nor in the activity of SOD, CAT, GPx and GST in gills. In liver, DCF inhibited SOD and GPx activity, CAF inhibited CAT activity, the mixture inhibited SOD and GST activity; although only fish exposed to CAF showed increased hepatic LPO. Under these experimental conditions, no effect on COX activity was observed, nor cytotoxic and genotoxic damage. The most pronounced effects were caused by the drugs separately, since both compounds altered the enzymes, but only CAF triggered LPO, showing more harmful effects.

METHODOLOGY OF TOXICOLOGICAL EFFECTS ASSESSMENT IN AQUATIC ECOSYSTEMS BY BIODIVERSITY INDICATORS USE

The implementation of the EU Water Framework Directive 2000/60/EC within Eastern European is now becoming of utmost significance. This is especially relevant to the territory of Ukrainian Polessie, which is characterized by specific geological and geomorphological conditions, excessive humidification and significant anthropogenic pressure on all components of ecosystems. In this section, we present a methodology for evaluating the content of specific toxicological substances based on a diversitological approach to the macrophyte composition of reservoirs. At the same time, the possibility to apply diversisologic indicators for the bio-indication of the content of heavy metals in coastal soils and bottom deposits was assessed. The most striking changes in the species composition are manifested at the points of the most significant anthropogenic pressure in the presence of toxic compounds in aquatic ecosystems. Significant variations in view indices were noted when the high concentration of heavy metals was reached in the bottom soil. The most significant influence on the species composition is due to high concentrations of the active forms of zinc and cuprum cations in both coastal soils and bottom deposits, although the excessive maximum limits allowed were only in the second group of substances. The close correlation between the content of all investigated groups of heavy metals in bottom deposits and species numbers, the index of dominance, Shannon Diversity Index, and Pielou’s Evenness Index were established. For Margalef Species Richness Index, close dependencies were established for active forms of cations of nickel, cobalt, zinc and cadmium, for other groups the bonds were weak. For Sørensen–Dice Index weaknesses were found with the contents of active forms of cations of nickel and chromium; for other groups of active forms of heavy metals, except cobalt cations, close ties were established as well.

Diclofenac and carbamazepine removal from domestic wastewater using a Constructed Wetland-Solar Photo-Fenton coupled system

The presence of pharmaceutical compounds in aquatic ecosystems may affect both biota and human health because these micropollutants are capable of altering the metabolism and reproduction capacity of the live organisms of the aquatic ecosystems. The main route of entry of these pollutants into the aquatic environment is through Wastewater Treatment Plants (WWTPs) effluents. Compounds such as diclofenac (DCF) and carbamazepine (CBZ) persist, undergoing little or no degradation during treatment. Coupled systems combining biological treatments and Advanced Oxidation Technologies (AOTs) represent an alternative to reduce the risk of the presence of pharmaceuticals in the environment by achieving high removal efficiency at a low cost. This research evaluated the performance of a coupled system integrated by Horizontal Subsurface Flow Constructed Wetland (CW HSSF) and Solar Photo-Fenton at laboratory scale under America tropical conditions for the removal of DCF and CBZ from domestic wastewater at 15 μg L−1, on average. Three Fe2 +/H2O2 ratios (0.1, 0.3, and 0.8) were tested. Concentrations of DCF, CBZ, organic matter (DOC), Total Nitrogen (TN), and in situ variables were measured throughout the experiment.Removal efficiencies up to 92% and 86% were achieved for DCF and CBZ, respectively, using the Fe2+/H2O2 ratio of 0.1. There were no significant differences between the Fe2+/H2O2 ratios used (p < .05), but significantly greater efficiencies were achieved when CW was coupled with solar Photo-Fenton (40% only CW and 92% coupled system). Additionally, the coupled system showed a removal efficiency of organic matter (DOC) and total nitrogen (TN) greater than 61%. The concentration of DOC and TN, pH, solar UV radiation, and peroxide consumption had no significant effect on the removal efficiency of DCF and CBZ.

Exploring anammox bacteria ecology to improve nitrogen removal in wastewater treatment

Exploring anammox bacteria ecology to improve nitrogen removal in wastewater treatment

Survey of Intersex (Testicular Oocytes) in Black Crappie Collected from the Illinois River Waterway

Abstract Researchers have documented intersex (testicular oocytes) in male fishes in many species worldwide and prevalence of the condition is strongly related to exposure to endocrine-disrupting compounds in aquatic ecosystems. There is no available knowledge about the incidence of intersex in Black Crappie Pomoxis nigromaculatus, an important North American sport fish. The objective of this survey was to investigate the prevalence and distribution of the intersex condition in Black Crappie collected from portions of the Illinois River waterway. We collected and examined 83 Black Crappie. We observed testicular oocytes in 22 individuals (27% intersex), representing the first documentation of intersex condition in wild Black Crappie. The number of oocytes that we observed in intersex Black Crappie ranged from 1 to 67. We documented intersex in individuals collected from all habitats, but there were no significant differences in the prevalence of the condition (Kruskal–Wallis P = 0.56) or the number of oocytes present (P = 0.25) in intersex males from the different habitats. Permutational multivariate analysis of variance indicated that morphometric parameters varied significantly among locations (P = 0.0001), but did not vary significantly between intersex and normal males. We have little information about the current distribution of endocrine-disrupting compounds in the specific regions where we collected Black Crappie for our study. However, we believe our study represents a valuable effort to detect the condition in an important sport fish and lays a foundation for future research.

Methylation and dealkykation of tin compounds by sulfate- and nitrate-reducing bacteria

In this study, axenic cultures of sulfate-reducing (SRB) and nitrate-reducing (NRB) bacteria were examined for their ability to methylate inorganic tin and to methylate or dealkylate butyltin compounds. Environmentally relevant concentrations of natural abundance tributyltin (TBT) and 116Sn-enriched inorganic tin were added to bacterial cultures to identify bacterial-mediated methylation and dealkylation reactions. The results show that none of the Desulfovibrio strains tested was able to induce any transformation process. In contrast, Desulfobulbus propionicus strain DSM-6523 degraded TBT either under sulfidogenic or non-sulfidogenic conditions. In addition, it was able to alkykate 116Sn-enriched inorganic tin leading to the formation of more toxic dimethyltin and trimethyltin. A similar capacity was observed for incubations of Pseudomonas but with a much greater dealkykation of TBT. As such, Pseudomonas sp. ADR42 degraded 61% of the initial TBT under aerobic conditions and 35% under nitrate-reducing conditions. This is the first work reporting a simultaneous TBT degradation and a methylation of both inorganic tin species and TBT dealkykation products by SRB and NRB under anoxic conditions. These reactions are environmentally relevant as they can control the mobility of these compounds in aquatic ecosystems; as well as their toxicity toward resident organisms.

Forced and long-term degradation assays of tenoxicam, piroxicam and meloxicam in river water. Degradation products and adsorption to sediment

The fate of the pharmaceutical drugs tenoxicam, piroxicam and meloxicam in river water is evaluated here for first time. So, biological, photochemical and thermal degradation assays have been conducted to estimate their degradation rates and know their degradation products. Results indicated that the direct sunlight irradiation, without any protection, promoted a fast degradation of the oxicams while the chemical reactions in solution were less important. The biological degradation in water was negligible except for tenoxicam in whose case its influence was scarce. When the exposition of river water to sunlight was partially limited and kept under the natural day-night cycle, as occurs inside a body of water, tenoxicam, piroxicam and meloxicam (at 2 μg L−1) were detected during a period of 15, 27 and 45 days, respectively. Residues were monitored by ultra-pressure liquid chromatography/quadrupole time-of-flight/mass spectrometry after solid-phase extraction and several degradation products were found (10 for tenoxicam, 9 for piroxicam and 7 for meloxicam) and monitored over time. Their structures were proposed from the molecular formulae and fragmentation observed in high-resolution tandem mass spectra; the nature of the transformation products found in the long-term resulted to be very variable for each oxicam. Furthermore, the degradation in presence of river sediment was also monitored over time, with some differences being noted; the adsorption coefficients of the compounds on sediment were calculated, meloxicam exhibited a higher sorption capacity. The ecotoxicity of the different compounds in aquatic ecosystems was predicted, too.

The impact of chemosensitisation on bioaccumulation and sediment toxicity

Cellular multixenobiotic resistance (MXR) transport proteins enhance the efflux of numerous organic pollutants. However, MXR proteins may be blocked or saturated by xenobiotic compounds, acting as inhibitors — also called chemosensitisers. Although effective on a cellular level, the environmental relevance of chemosensitisers has not been conclusively demonstrated. Since sediments are an important source of bioaccumulating compounds in aquatic ecosystems, sediments and sediment–associated hydrophobic pollutants were investigated for their potential to increase exposure and toxicity in the presence of chemosensitisation. In this study, we address this issue by (1) comparing the net uptake of 17 hydrophobic environmental pollutants by zebrafish (Danio rerio) embryos in the presence and absence of the model chemosensitiser verapamil and (2) investigating the impact of verapamil on the dose–dependent effect on zebrafish embryos exposed to polluted sediment extracts. None of the 17 pollutants showed a reproducible increase in bioaccumulation upon chemosensitisation with verapamil. Instead, internal concentrations were subject to intra–species variation by a factor of approximately two. However, a significant increase in toxicity was observed upon embryo co–exposure to verapamil for one of three sediment extracts. In contrast, another sediment extract exhibited less toxicity when combined with verapamil. In general, the results indicate only a minor impact of verapamil on the uptake of moderately hydrophobic chemicals in zebrafish embryos.

Proteomic changes in Corbicula fluminea exposed to wastewater from a psychiatric hospital.

The increase use of pharmaceutical compounds in veterinary practice and human population results in the ubiquitous presence of these compounds in aquatic ecosystems. Because pharmaceuticals are highly bioactive, there is concern about their toxicological effects in aquatic organisms. Therefore, the aim of this study was to assess the effects of an effluent from a psychiatric hospital (containing a complex mixture of 25 pharmaceutical compounds from eleven therapeutic classes) on the freshwater clam Corbicula fluminea using a proteomic approach. The exposure of C. fluminea to this complex effluent containing anxiolytics, analgesics, lipid regulators, beta blockers, antidepressants, antiepileptics, antihistamines, antihypertensives, antiplatelets and antiarrhythmics induced protein changes after 1 day of exposure in clam gills and digestive gland more evident in the digestive gland. These changes included increase in the abundance of proteins associated with structural (actin and tubulin), cellular functions (calreticulin, proliferating cell nuclear antigen (PCNA), T complex protein 1 (TCP1)) and metabolism (aldehyde dehydrogenase (ALDH), alcohol dehydrogenase, 6 phosphogluconate dehydrogenase). Results from this study indicate that calreticulin, PCNA, ALDH and alcohol dehydrogenase in the digestive gland and T complex protein 1 (TCP1)) and 6 phosphogluconate dehydrogenase in the gills represent useful biomarkers for the ecotoxicological characterization of psychiatric hospital effluents in this species.