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.
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
Experiments were performed to study the effects of short and long-term exposure to bisphenol A (BPA) on a freshwater crustacean isopod Asellus aquaticus (L.). Two life stages of isopods were exposed ...to a range of BPA concentrations, from aqueous and two dietary sources, in the form of with BPA spiked conditioned alder leaf (Alnus glutinosa) discs, or spiked formulated sediment, to determine the relative importance of each source of exposure on the uptake of this contaminant. Several lethal and sublethal endpoints were evaluated in this study to measure the potential effects of BPA on A. aquaticus, including mortality, growth and feeding rate inhibition, mobility inhibition, de-pigmentation and molting disturbances. They signify a correlation to BPA levels and a difference in BPA uptake efficiency from different uptake sources. Results of acute exposure to BPA show a greater sensitivity of test systems using juvenile specimens with a 96h LC50 of 8.6mgL−1 BPA in water medium and a 96h LC50 of 13.5mgL−1 BPA in sediment. In comparison, adult isopods show a 96h LC50 of 25.1mgL−1 BPA in water medium and a 96h LC50 of 65.1mgL−1 BPA in sediment. Observed endpoints of chronic exposures suggest the alder leave discs to be the most efficient uptake source of BPA, in contrast to uptake from water or heterogeneous sediment. Significant (p<0.05) growth inhibition, with a 21d NOEC of 0.5/2.5mgL−1 (for juvenile/adult organisms), and feeding rate inhibition, with a 21d NOEC of 0.5/1.0mgL−1 (for juvenile/adult organisms), were proven to be the most sensitive toxicity endpoints. An even more sensitive effect turned out to be molting frequency, which was significantly reduced; a 21d NOEC was 1.0mgL−1 of BPA for adult organisms and an even lower 21d NOEC of 0.05mgL−1 of BPA for juveniles. The observed endpoints are recorded at very low, non-toxic exposure concentrations, indicating that BPA acts as an endocrine disrupting compound, as well as a toxic substance. We also determined the importance of the direct dietary uptake of the pollutants, significant for juveniles as well as adult animals.
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•Toxic and endocrine disrupting effects of BPA on Asellus aquaticus were evaluated.•The effects intensity depends on exposure time, life stage, and BPA uptake route.•Most efficient BPA uptake was from feeding with contaminated alder leaves.•Molting was identified as most sensitive endocrine disruption endpoints.•Growth and feeding rate were identified as most sensitive toxicity endpoints.
Bisphenol A (BPA) is a well-known endocrine disruptor with adverse oestrogen-like effects eliciting adverse effects in humans and wildlife. For this reason it is necessary to set up an efficient ...removal of BPA from wastewaters, before they are discharged into surface waters. The aim of this study was to compare the efficiency of BPA removal from aqueous samples with photolytic, photocatalytic, and UV/H2O2 oxidation. BPA solutions were illuminated with different bulbs (halogen; 17 W UV, 254 nm; and 150 W UV, 365 nm) with or without the TiO
P-25 catalyst or H
(to accelerate degradation). Acute toxicity and oestrogenic activity of treated samples were determined using luminescent bacteria (Vibrio fischeri), water fleas (Daphnia magna), zebrafish embryos (Danio rerio), and Yeast Estrogen Screen (YES) assay with genetically modified yeast Saccharomyces cerevisiae. The results confirmed that BPA is toxic and oestrogenically active. Chemical analysis showed a reduction of BPA levels after photolytic treatment and 100 % conversion of BPA by photocatalytic and UV/H
oxidation. The toxicity and oestrogenic activity of BPA were largely reduced in photolytically treated samples. Photocatalytic oxidation, however, either did not reduce BPA toxic and oestrogenic effects or even increased them in comparison with the baseline, untreated BPA solution. Our findings suggest that chemical analysis is not sufficient to determine the efficiency of advanced oxidation processes in removing pollutants from water and needs to be complemented with biological tests.
A je dobro poznan motilec endokrinega sistema z estrogensko aktivnostjo in škodljivimi učinki na ljudi in živali. Zaradi tega se pojavlja potreba po učinkovitem odstranjevanju BPA iz odpadnih voda. V raziskavi smo proučevali učinkovitost odstranjevanja BPA iz vodnih vzorcev s procesi fotolitske, fotokatalitske in UV/H
oksidacije. Med poskusom smo vodne vzorce osvetljevali s tremi različnimi žarnicami (halogensko, 17 W UV, 254 nm in 150 W UV, 365 nm). V procesih foto(kata)litske oksidacije smo uporabili H
in katalizator TiO
P-25 (Degussa). Akutno strupenost in estrogensko aktivnost BPA ter tretiranih vzorcev smo določili s testi strupenosti na luminiscentne bakterije (Vibrio fischeri), vodne bolhe (Daphnia magna), zarodke cebric (Danio rerio) in YES testom z gensko spremenjenimi kvasovkami Saccharomyces cerevisiae. Rezultati so pokazali, da je BPA za vodne organizme strupen in estrogensko aktiven. Kemijske analize so pokazale zmanjšanje vsebnosti BPA po fotolitski oksidaciji in popolno odstranitev BPA iz vodnih vzorcev po fotokatalitski oksidaciji in UV/H
O oksidaciji. Strupenost in estrogenska aktivnost sta se zmanjšali pri vzorcih, tretiranih s fotolitsko oksidacijo, sorazmerno z zmanjšanjem vsebnosti BPA. Pri fotokatalitsko tretiranih vzorcih se kljub popolni pretvorbi BPA strupenost in estrogenska aktivnost nista zmanjšali ali pa sta se celo zvišali v primerjavi z izhodnim vzorcem. Ugotovili smo, da ugotavljanje učinkovitosti odstranjevanja BPA iz vodnih vzorcev z naprednimi oksidacijskimi procesi z uporabo kemijskih analiz ne zadostuje. Potrebna so biološka testiranja, ki dokažejo morebitno preostalo strupenost in estrogensko aktivnost obdelanih vzorcev.
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