The use of a very effective insecticide against sucking pests, neonicotinoid imidacloprid, has been increasing extensively. For this reason elevated concentrations are expected in aquatic ...environment. Despite this fact, there is still a lack of data available on its possible risk for the environment. In this study, the potential hazards of imidacloprid and its commercial product Confidor SL 200 to aquatic environment were identified by the acute and chronic toxicity assessment using bacteria
Vibrio fischeri, algae
Desmodesmus subspicatus, crustacean
Daphnia magna, fish
Danio rerio and the ready biodegradability determination. We found out, that imidacloprid was not highly toxic to tested organisms in comparison to some other environmental pollutants tested in the same experimental set-up. Among the organisms tested, water flea
D. magna proved to be the most sensitive species after a short-term (48
h EC50
=
56.6
mg
L
−1) and long-term exposure (21
d NOEC
=
1.25
mg
L
−1). On the contrary, the intensified toxicity of Confidor SL 200 in comparison to analytical grade imidacloprid was observed in the case of algae and slight increase of its toxicity was detected testing daphnids and fish. The activities of cholinesterase, catalase and glutathione S-transferase of daphnids were not early biomarkers of exposure to imidacloprid and its commercial product. Imidacloprid was found persistent in water samples and not readily biodegradable in aquatic environment. Due to increased future predicted use of commercial products containing imidacloprid and the findings of this work, we recommend additional toxicity and biodegradability studies of other commercial products with imidacloprid as an active constituent.
Production of bisphenol A (BPA) analogues such as bisphenol F (BPF) and bisphenol AF (BPAF) has recently increased, due to clear evidence of adverse effects of BPA on humans and wildlife. Bisphenols ...(BPs) have already been released into aquatic environment without previous available information about potential adverse effects of BPs and their potential risk to aquatic ecosystems. In this study, lethal and sublethal effects of BPF and BPAF to bacteria, algae, crustacea and fish embryos were investigated and the results were compared to the adverse effects obtained for BPA. We found that BPAF was the most toxic compound to Daphnia magna, Danio rerio and Desmodesmus subspicatus; the lowest 72 h EC50 (median effective concentration) and 21 d NOEC (no observed effect concentration) values were determined at 2.2 mg/L regarding zebrafish hatching success and 0.23 mg/L of BPAF obtained for growth and reproduction of water fleas, respectively. In most cases, BPA was more toxic to D. magna, D. rerio and D. subspicatus in comparison to BPF, but pigmentation of zebrafish embryos after 48 h of exposure and reproduction of water fleas after 21-day D. magna reproductive test exposure to BPF were much more impaired. Risk quotients (measured environmental concentration/21 d NOEC) showed that BPA, BPF and BPAF are recently not chronically hazardous to the survival, reproduction and growth of water fleas in surface waters. On the other hand, we importantly show that currently present BPAF concentrations in surface waters could cause a potential ecological risk to aquatic organisms. In the near future, higher concentrations of BPF and BPAF in surface waters are anticipated and for this reason further testing using test systems with various aquatic species and endpoints are needed to provide additional information about toxic impacts of BPF and BPAF on aquatic biota.
•Higher toxicity of BPAF in comparison to BPF and BPA.•BPA was more toxic to the majority of tested organisms in comparison to BPF.•BPAF could cause ecological risk to aquatic organisms.•Industrial replacement of BPA with BPAF is questionable.
We reveal that BPAF was found to be more toxic to tested organisms than BPA and BPF and it could cause ecological risk to aquatic organisms.
Catalytic wet-air oxidation (CWAO) of aqueous solutions of bisphenol A (BPA) was investigated in a trickle-bed reactor at temperatures up to 230 °C and oxygen partial pressure of 10.0 bar over TiO2 ...and Ru/TiO2 solids. It was observed that in the given range of operating conditions BPA undergoes both noncatalyzed and catalyzed oxidation routes. The employed Ru/TiO2 catalyst containing 3.0 wt % of metallic phase enabled complete removal of BPA and more than 96% of TOC removal at temperatures of 200 °C and above. No catalyst deactivation occurred that could be attributed to the dissolution of active ingredient material. At these conditions, no carbonaceous deposits were accumulated on the catalyst surface. The acute toxicity of end-product solutions to organisms from different taxonomic groups and estrogenicity determined by the genetically modified yeast, compared with those of the feed solutions, was significantly reduced by CWAO treatment over the Ru/TiO2 catalyst. For comparison, oxidative destruction of BPA was also investigated in this study by means of either photolytic or heterogeneous photocatalytic oxidation. A commercial TiO2 photocatalyst illuminated by UV light enabled complete removal of BPA; however, lower decrease of toxicity and estrogenicity in the treated solution was observed.
In the present study a biological “in vivo” assay, with freshwater isopod Asellus aquaticus, was used to define and evaluate the potential impact of the wastewater treatment plant (WWTP) wastewaters ...on local wildlife. Samples of both untreated and mechanically and biologically treated WWTP wastewater, were tested in the presence and absence of the formulated sediment for their lethal and sublethal effects. Chronic exposures to wastewater samples caused concentration dependent reduced locomotion, body pigmentation and molting frequency in exposed organisms. The observed effects indicate the overall toxicity and endocrine disruption of the wastewater samples. In contrast stimulations of the feeding rate and growth rate of the test organisms during the chronic exposure to sublethal levels of wastewater samples were observed, indicating an improvement in nutritional quality of the wastewater. The most sensitive exposure endpoint was molting frequency of tested organisms, which indicated the presence of estrogenically active endocrine disrupting compounds (EDCs). Raw wastewater caused up to 42% molting frequency reduction of exposed A. aquaticus when exposed to five times diluted untreated wastewater sample, while undiluted treated wastewater caused a 61% molting frequency reduction. The presence of estrogenically active compounds in the wastewater was confirmed with the yeast estrogen screen assay (YES test), which assigned the highest estrogenic activity to a mechanically and biologically treated wastewater sample, and lower estrogenic activity to all other tested samples. The importance of presence of the formulated sediment was determined, as it lessened the effects of all WWTP wastewater samples in all observed exposures.
•Toxic and endocrine disrupting effects of WWTP wastewaters were evaluated.•A high toxicity towards Asellus aquaticus was caused by WWTP influents.•WWTP effluents were less toxic, however higher estrogenic activity was observed.•Presence of sediment reduced adverse effects on test organism.•The most sensitive endpoints indicating the estrogenic activity, was molting.
Catalytic wet air oxidation (CWAO) of aqueous bisphenol A (BPA) solution was studied in a continuous-flow trickle-bed reactor in the presence of titanate nanotube-based catalysts. These active ...metal-free solids were prepared by alkaline hydrothermal synthesis followed by heat treatment at temperatures ranging from 300 to 700 °C, so that they would have varying physicochemical properties. The aim of the study was to investigate the removal efficiency of titanate nanotube-based catalysts used in the CWAO process to remove toxicity and estrogenicity of BPA at a very short space time of 0.6 min·gCAT·g–1. In addition, noncatalytic BPA degradation in the presence of inert SiC particles was also performed. As a result, significantly higher estrogenicity and toxic effects of the liquid-phase sample compared to the catalytic oxidation experiments were observed. Complete removal of estrogenicity and high reduction of toxicity from aqueous solution were achieved at 210 °C over 0.5 g of catalyst that had been annealed at 600 °C.
With the advancement of drug delivery systems based on mesoporous silica nanoparticles (MSNs), a simple and efficient method regulating the drug release kinetics is needed. We developed ...redox-responsive release systems with three levels of hindrance around the disulfide bond. A model drug (rhodamine B dye) was loaded into MSNs’ mesoporous voids. The pore opening was capped with β-cyclodextrin in order to prevent leakage of drug. Indeed, in absence of a reducing agent the systems exhibited little leakage, while the addition of dithiothreitol cleaved the disulfide bonds and enabled the release of cargo. The release rate and the amount of released dye were tuned by the level of hindrance around disulfide bonds, with the increased hindrance causing a decrease in the release rate as well as in the amount of released drug. Thus, we demonstrated the ability of the present mesoporous systems to intrinsically control the release rate and the amount of the released cargo by only minor structural variations. Furthermore, an in vivo experiment on zebrafish confirmed that the present model delivery system is nonteratogenic.
The effects of ingested nano-sized titanium dioxide (TiO2; anatase, 15 nm) on the terrestrial isopod Porcellio scaber (Isopoda, Crustacea) after short-term (3-d) dietary exposure were studied. ...Activities of antioxidant enzymes, such as catalase (CAT) and glutathione-S-transferase (GST), in digestive glands were affected in a dose-independent manner, but higher-level isopod endpoints, including weight change, feeding rate, food assimilation efficiency, and survival, were not affected up to the highest tested concentration of TiO2 in food (3,000 μg/g). Exposure concentrations of 0.5, 2,000, and 3,000 μg nonsonicated TiO2/g food decreased CAT and GST activities, but intermediate concentrations (1, 10, 100, and 1,000 μg/g food) did not result in significant changes of enzyme activities. When the dispersion of TiO2 was sonicated, no effects on enzyme activities or higher-level biomarkers were observed. The experimental setup with terrestrial isopods designed for dissolved chemicals also is suitable for testing the effects of ingested nanoparticles, but the presentation of toxicity data needs to be adapted according to the mode of action of the nanoparticles and their specific characteristics.
Background, aim and scope For reliable environmental risk assessment of pollutants, knowledge on the effects at different levels of biological organisation is needed. During the early days of ...biomarker research in environmental studies approximately two decades ago, biochemical biomarkers were considered as the most promising tool for such purposes. Among these, three enzymes have often been studied: catalase (CAT), glutathione S-transferase (GST) and cholinesterase (ChE). However, despite their intensive research, their measurements in invertebrates have not been commonly applied in environmental risk assessment (ERA) or for regulatory purposes. Main features In the present review, we summarise our past experiences in biochemical biomarker research in two crustacean species: water flea Daphnia magna and terrestrial isopod Porcellio scaber. This is to orientate their use and to provide recommendations for the use of novel biomarkers in environmental studies, such as proteomic or genomic responses. Results and discussion We assessed the intrinsic properties of biochemical biomarkers CAT, GST and ChE in the D. magna and the isopod P. scaber. It was found that they are not in agreement with the expectations that were previously given for their use in environmental studies. To advance their use in environmental risk assessment, we suggest that based on their properties, their role should be more specifically defined. ERA includes several distinct steps, among them hazard identification, effect assessment and finally risk characterisation, each of which requires a different type of toxicity data. We recommend that the use of biochemical markers is most appropriate for hazard identification because this is a procedure whose purpose is to characterise the potential hazard of the substance in question and is more flexible in terms of using different tools. Furthermore, our results imply that biochemical markers are not always more sensitive than whole-organism responses, as was anticipated. Their sensitivity depends on the mode of action, duration of exposure and test species. Therefore, we suggest that combining both a battery of biomarkers from different levels of biological organisation and an array of biomarkers within a single level could identify hazard adequately. Conclusions The lesson learnt from biochemical biomarkers in environmental studies utilizing crustacean model species is that, for successful application of each group of biomarkers, their intrinsic properties are needed to be known before an (eco)toxicity study is designed. We suggest that a substantial body of experience obtained with biochemical biomarkers should be exploited to new emerging biomarkers in environmental studies in order to facilitate their application. Recommendations and perspectives The future of biomarkers lies in a combination of traditional biochemical and new-generation biomarkers. The latter are not only a potential replacement for existing biomarkers but will also provide new knowledge which might encourage renewed research and development of traditional biomarkers. For research purposes, complete ecotoxicity information should include contributions from molecular fingerprint of an organism, as well as whole organism, population and ecosystem responses. Still, the type of biomarkers used for routine purposes will depend on their reproducibility, their ease of use, robustness, affordability of the methodology and the type of chemicals, organisms and ecosystem of interest.
Bisphenol A (BPA) is a well known endocrine disruptor. Significantly less is known about its ability to induce antioxidant defense and oxidative stress in aquatic organisms. This is an interesting ...subject because BPA can act both as a prooxidant (induces the formation of reactive oxygen species) and an antioxidant. The aim of the present study was to elucidate if BPA induces changes in the activities of antioxidant enzymes catalase (CAT) and glutathione S-transferases (GSTs) and the level of lipid peroxidation in crustacean Daphnia magna. These biomarkers were followed after acute (48h) and chronic (21d) exposure period. Interestingly, CAT and GSTs were changed in the same manner after both exposure durations. The most observable change in daphnids was the increase of GSTs activities, measured with 1,2-chloro-4-dinitrobenzene as a substrate. No GSTs activities with ethacrynic acid and 1,2-dichloro-4-nitrobenzene as substrates were detected. The activity of CAT and the level of lipid peroxidation remained unchanged in daphnids exposed to sublethal concentrations of BPA. The reproduction rate was considerably affected already at 1.73mg/L while the growth was only affected at the highest concentration (13.8mg/L), where also significant mortality was observed.
► We studied the effect of BPA on antioxidant system of daphnids. ► Daphnids successfully detoxify sublethal levels of BPA via GSTs route. ► No severe oxidative stress at these concentrations probably occurs. ► The reproduction of daphnids is considerably affected already at 1.73mg/L of BPA.
Poor crystallinity and applications restricted to only UV region of titanate nanotubes (TNTs) generated numerous routes towards high surface area visible photocatalysts. In this study, TNTs were ...prepared via alkaline hydrothermal synthesis route followed by deposition of visible light sensitive CuO on their surface via photoreduction method under anoxic conditions. Photodeposited Cu(II) oxide was confirmed by means of EPR and DR-UV-Vis spectroscopy. Further annealing in 5% H
2
/N
2
gas mixture introduced oxygen vacancies associated with Ti
3+
defect sites, which additionally enhanced photocatalytic activity under visible light. Using such photocatalyst, almost complete inactivation of bacteria
Escherichia coli
was achieved within 60 min of illumination with visible light.
Graphical Abstract
