Estrogenic and AhR activities in dissolved phase and suspended solids from wastewater treatment plants
ABSTRACT The distribution of estrogen receptor (ERalpha) and Aryl Hydrocarbon Receptor (AhR) activities between the dissolved phase and suspended solids were investigated during wastewater treatment. Three wastewater treatment plants with different treatment technologies (waste stabilization ponds (WSPs), trickling filters (TFs) and activated sludge supplemented with a biofilter system (ASB)) were sampled. Estrogenic and AhR activities were detected in both phases in influents and effluents. Estrogenic and AhR activities in wastewater influents ranged from 41.8 to 79 ng/L E(2) Eq. and from 37.9 to 115.5 ng/L TCDD Eq. in the dissolved phase and from 5.5 to 88.6 ng/g E(2) Eq. and from 15 to 700 ng/g TCDD Eq. in the suspended solids. For both activities, WSP showed greater or similar removal efficiency than ASB and both were much more efficient than TF which had the lowest removal efficiency. Moreover, our data indicate that the efficiency of removal of ER and AhR activities from the suspended solid phase was mainly due to removal of suspended solids. Indeed, ER and AhR activities were detected in the effluent suspended solid phase indicating that suspended solids, which are usually not considered in these types of studies, contribute to environmental contamination by endocrine disrupting compounds and should therefore be routinely assessed for a better estimation of the ER and AhR activities released in the environment.
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- "Among the most well known effects, it has been reported that triclosan impairs algal growth and develops bacterial resistance (Orvos et al., 2002) whereas pharmaceutical mixtures containing carbamazepine, ibuprofen, and clofibric acid have also been found to be toxic for algae (Cleuvers, 2003). Estrogenicity has already been demonstrated for many contaminants such as natural and synthetic hormones and alkylphenols commonly detected in wastewaters (Dagnino et al., 2010). Although the removal of EOCs may be partially achieved by the application of conventional wastewater treatment plants (WWTPs) combined to advanced tertiary treatment processes (Rosal et al., 2010), their high cost limits the widespread application of these treatment technologies. "
ABSTRACT: The capacity of a hybrid constructed wetland (CW) system consisting of two vertical flow (VF) CWs working alternatively (3m(2)), one horizontal flow (HF) CW (2m(2)) and one surface flow (FWS) CW (2m(2)) in series to eliminate 13 emerging organic contaminants (EOCs) under three different hydraulic loading rates (HLRs) (0.06, 0.13 and 0.18m d(-1) considering the area of the two VF beds) was studied through a continuous injection experiment. General toxicity, dioxin-like activity, antimicrobial activity and estrogenicity were also measured under the highest hydraulic loading rate. The hybrid system was highly efficient on the removal of total injected EOCs (except for antibiotics, 43±32%) at all three HLRs (87±10%). The removal efficiency in the hybrid CW system showed to decrease as the HLR increased for most compounds. The VF wetlands removed most of the injected EOCs more efficiently than the other two CWs, which was attributable to the predominant aerobic degradation pathways of the VF beds (70±21%). General toxicity was reduced up to 90% by the VF beds. Estrogenicity and dioxin-like activity were similarly reduced by the VF and the HF wetlands, whereas antimicrobial activity was mainly removed by the FWS wetland. Bearing this in mind, this injection study has demonstrated that the use of hybrid CW systems is a suitable wastewater technology for removing EOCs and toxicity even at high HLRs.Science of The Total Environment 11/2013; 470-471C:1272-1280. DOI:10.1016/j.scitotenv.2013.10.065 · 4.10 Impact Factor
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- "Ivermectin was tested for its ability to activate rodent transcription factors (murine CAR, murine PXR and rat AhR) by using three different reporter cell lines (HG 5 LN-mCAR, HG 5 LNmPXR and H4IIE XRE-LUC) in which PXR, CAR and AhR agonists or antagonists induced or repressed luciferase gene expression. Activation was measured in these cells in the presence of increased concentrations of ivermectin from 10 À8 M to 3.3 Â 10 À6 M. The vehicle alone (DMSO) was used as negative control (luciferase activity baseline set to 1) and known reference effectors were used as positive control, as already described . Results are presented in Table 2. "
ABSTRACT: Ivermectin is widely used in human and veterinary medicine for the control of helminth infections. Ivermectin is known to interact with P-glycoprotein (P-gp/MDR1), being a good substrate and a potent inhibitor, however, the influence of ivermectin on the expression of the transporter has not been investigated. Expression of P-glycoprotein was investigated in cultured mouse hepatocytes acutely exposed to ivermectin. The two P-glycoprotein murine isoforms, Mdr1a and Mdr1b, mRNA levels were assessed by real-time RT-PCR. Ivermectin induced a clear time- and concentration-dependent up-regulation of Mdr1a and Mdr1b mRNA levels (as early as a 12-h exposure and up to 2.5-fold at 10μM). Moreover, ivermectin-treated cells displayed enhanced cellular efflux of the P-glycoprotein substrate calcein that was inhibited by the P-glycoprotein blocker valspodar, providing evidence that the ivermectin-induced P-glycoprotein was functional. The mechanisms underlying these effects were investigated. Ivermectin-mediated Mdr1 mRNA induction was independent of the two nuclear receptors CAR and PXR, which are known to be involved in drug transporters regulation. Moreover, by using reporter cell lines that detects specific ligand-activated transcription factors, we showed that ivermectin did not displayed CAR, PXR or AhR ligand activities. However, studies with actinomycin D revealed that the half-life of Mdr1a and Mdr1b mRNA were significantly prolonged by two-fold in ivermectin-treated cells suggesting a post-transcriptional mode of ivermectin regulation. This study demonstrates for the first time that ivermectin induces P-glycoprotein overexpression through post-transcriptional mRNA stabilization, thus offering insight into the mechanism of reduced therapeutic efficacy and development of ivermectin-resistant parasites.Biochemical pharmacology 01/2012; 83(2):269-78. DOI:10.1016/j.bcp.2011.10.010 · 5.01 Impact Factor
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ABSTRACT: Concerns about endocrine disrupting compounds in sewage treatment plant (STP) effluents give rise to the implementation of advanced treatment steps for the elimination of trace organic contaminants. The present study investigated the effects of ozonation (O(3)) and activated carbon treatment (AC) on endocrine activities [estrogenicity, anti-estrogenicity, androgenicity, anti-androgenicity, aryl-hydrocarbon receptor (AhR) agonistic activity] with yeast-based bioassays. To evaluate the removal of non-specific toxicity, a cytotoxicity assay using a rat cell line was applied. Wastewater (WW) was sampled at two STPs after conventional activated sludge treatment following the secondary clarifier (SC) and after subsequent advanced treatments: O(3), O(3) + sand filtration (O(3-SF)), and AC. Conventional treatment reduced estrogenicity, androgenicity, and AhR agonistic activity by 78-99% compared to the untreated influent WW. Anti-androgenicity and anti-estrogenicity were not detectable in the influent but appeared in SC, possibly due to the more effective removal of respective agonists during conventional treatment. Endocrine activities after SC ranged from 2.0 to 2.8 ng/L estradiol equivalents (estrogenicity), from 4 to 22 μg/L 4-hydroxytamoxifen equivalents (anti-estrogenicity), from 1.9 to 2.0 ng/L testosterone equivalents (androgenicity), from 302 to 614 μg/L flutamide equivalents (anti-androgenicity), and from 387 to 741 ng/L β-naphthoflavone equivalents (AhR agonistic activity). In particular, estrogenicity and anti-androgenicity occurred in environmentally relevant concentrations. O(3) and AC further reduced endocrine activities effectively (estrogenicity: 77-99%, anti-androgenicity: 63-96%, AhR agonistic activity: 79-82%). The cytotoxicity assay exhibited a 32% removal of non-specific toxicity after O(3) compared to SC. O(3) and sand filtration reduced cytotoxic effects by 49%, indicating that sand filtration contributes to the removal of toxicants. AC was the most effective technology for cytotoxicity removal (61%). Sample evaporation reduced cytotoxic effects by 52 (AC) to 73% (O(3)), demonstrating that volatile substances contribute considerably to toxic effects, particularly after O(3). These results confirm an effective removal or transformation of toxicants with receptor-mediated mode of action and non-specific toxicants during O(3) and AC. However, due to the limited extractability, polar ozonation by-products were neglected for toxicity analysis, and hence non-specific toxicity after O(3) is underestimated.Water Research 10/2010; 45(3):1015-24. DOI:10.1016/j.watres.2010.10.008 · 5.53 Impact Factor