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Molecular effects and bioaccumulation of levonorgestrel in the non-target organism Dreissena polymorpha
2011
Contardo-Jara, Valeska | Lorenz, Claudia | Pflugmacher, Stephan | Nützmann, Gunnar | Kloas, Werner | Wiegand, Claudia
Bioaccumulation and effects of the contraceptive hormone levonorgestrel were examined in the non-target organism Dreissena polymorpha. Molecular biomarkers of biotransformation, elimination, antioxidant defence and protein damage were analyzed after exposure to increasing concentrations of levonorgestrel in a flow-through system. The lowest concentration (0.312 μg L⁻¹) was 100-fold bioconcentrated within four days. A decrease of the bioconcentration factor was observed within one week for the highest test concentrations (3.12 and 6.24 μg L⁻¹) suggesting enhanced excretory processes. The immediate mRNA up-regulation of pi class glutathione S-transferase proved that phase II biotransformation processes were induced. Disturbance of fundamental cell functions was assumed since the aryl hydrocarbon receptor has been permanently down-regulated. mRNA up-regulation of P-glycoprotein, superoxide dismutase and metallothioneine suggested enhanced elimination processes and ongoing oxidative stress. mRNA up-regulation of heat shock protein 70 in mussels exposed to the two highest concentrations clearly indicated impacts on protein damage.
Show more [+] Less [-]Toxicity profile of labile preservative bronopol in water: The role of more persistent and toxic transformation products
2011
Cui, Na | Zhang, Xiaoxiang | Xie, Qing | Wang, Se | Chen, Jingwen | Huang, Liping | Qiao, Xianliang | Li, Xuehua | Cai, Xiyun
Transformation products usually differ in environmental behaviors and toxicological properties from the parent contaminants, and probably cause potential risks to the environment. Toxicity evolution of a labile preservative, bronopol, upon primary aquatic degradation processes was investigated. Bronopol rapidly hydrolyzed in natural waters, and primarily produced more stable 2-bromo-2-nitroethanol (BNE) and bromonitromethane (BNM). Light enhanced degradation of the targeted compounds with water site specific photoactivity. The bond order analysis theoretically revealed that the reversible retroaldol reactions were primary degradation routes for bronopol and BNE. Judging from toxicity assays and the relative pesticide toxicity index, these degradation products (i.e., BNE and BNM), more persistent and higher toxic than the parent, probably accumulated in natural waters and resulted in higher or prolonging adverse impacts. Therefore, these transformation products should be included into the assessment of ecological risks of non-persistent and low toxic chemicals such as the preservative bronopol.
Show more [+] Less [-]Soil nitrogen transformations under elevated atmospheric CO₂ and O₃ during the soybean growing season
2011
Pujol Pereira, Engil Isadora | Chung, Haegeun | Scow, Kate | Sadowsky, M. J. (Michael J.) | van Kessel, Chris | Six, Johan
We investigated the influence of elevated CO₂ and O₃ on soil N cycling within the soybean growing season and across soil environments (i.e., rhizosphere and bulk soil) at the Soybean Free Air Concentration Enrichment (SoyFACE) experiment in Illinois, USA. Elevated O₃ decreased soil mineral N likely through a reduction in plant material input and increased denitrification, which was evidenced by the greater abundance of the denitrifier gene nosZ. Elevated CO₂ did not alter the parameters evaluated and both elevated CO₂ and O₃ showed no interactive effects on nitrifier and denitrifier abundance, nor on total and mineral N concentrations. These results indicate that elevated CO₂ may have limited effects on N transformations in soybean agroecosystems. However, elevated O₃ can lead to a decrease in soil N availability in both bulk and rhizosphere soils, and this likely also affects ecosystem productivity by reducing the mineralization rates of plant-derived residues.
Show more [+] Less [-]Uptake, tissue distribution and metabolism of the insecticide endosulfan in Jenynsia multidentata (Anablepidae, Cyprinodontiformes)
2011
Ballesteros, M.L. | Gonzalez, M. | Wunderlin, D.A. | Bistoni, M.A. | Miglioranza, K.S.B.
The study reports the accumulation, distribution and metabolism of technical endosulfan in Jenynsia multidentata. Adult females were exposed to acute sublethal concentrations (0.072, 0.288 and 1.4 μg L⁻¹). After 24 h, fish were sacrificed and gills, liver, brain, intestine and muscle were removed. Results show that both isomers of technical-grade endosulfan (α- and β-) are accumulated in fish tissues and biotransformation to endosulfan sulfate occurs at all concentrations tested. Significantly differences in endosulfan accumulation were only found at 1.4 μg L⁻¹ but not between the lowest concentrations. However a similar distribution pattern was observed at all exposure levels where liver, intestine and brain had the highest levels of α-, β-endosulfan and endosulfan sulfate. Moreover, liver and brain showed the highest endosulfan sulfate:α-endosulfan ratios due to high biotransfomation capacity. J. multidentata demonstrated to be a sensitive species under exposure to technical endosulfan and, therefore, could be used to assess aquatic pollution.
Show more [+] Less [-]Biomarker responsiveness in different tissues of caged Ruditapes philippinarum and its use within an integrated sediment quality assessment
2011
Ramos-Gómez, Julia | Coz, Alberto | Viguri, Javier R. | Luque, Ángel | Martín-Díaz, M Laura | DelValls, T Ángel
Biomarkers comprising activities of biotransformation enzymes (ethoxyresorufin-O-deethylase –EROD–, dibenzylfluorescein dealkylase –DBF–, glutathione S-transferase –GST), antioxidant enzymes (glutathione reductase –GR– and glutathione peroxidase –GPX), lipid peroxidation –LPO– and DNA strand breaks were analyzed in the clam Ruditapes philippinarum caged at Cádiz Bay, Santander Bay and Las Palmas de Gran Canaria (LPGC) Port (Spain). Sediments were characterized. Digestive gland was the most sensitive tissue to sediment contamination. In Cádiz Bay, changes in LPO regarding day 0 were related with metals. In LPGC Port, DBF, EROD, and GST activity responses suggested the presence of undetermined contaminants which might have led to DNA damage. In Santander Bay, PAHs were related with EROD activity, organic and metal contamination was found to be associated with GR and GST activities and DNA damage presented significant (p < 0.05) induction. R. philippinarum was sensitive to sediment contamination at biochemical level. Biomarkers allowed chemical exposure and sediment quality assessment.
Show more [+] Less [-]Endocrine effects of methoxylated brominated diphenyl ethers in three in vitro models
2011
Hu, Wei | Liu, Hongling | Sun, Hong | Shen, Ouxi | Wang, Xinru | Lam, Michael H.W. | Giesy, John P. | Zhang, Xiaowei | Yu, Hongxia
Methoxylated brominated diphenyl ethers (MeO-BDEs) in aquatic environments have been found to be primarily of natural origin in the marine environment and not from biotransformation of synthetic PBDEs. Two of the eight MeO-PBDEs (2′-MeO-BDE-68 and 6-MeO-BDE-47) that were detected in anchovy from the Yangtze River Delta, were natural products from marine organisms. So 2′-MeO-BDE-68 and 6-MeO-BDE-47 were chosen to study the potential to modulate androgen, estrogen, or thyroid hormone receptor- (AR, ER, ThR) mediated responses by use of reporter gene assays. 2′-MeO-BDE-68 was antiandrogenic at 50μM, estrogenic at 10μM and antiestrogenic at 10 and 50μM (IC₅₀=4.88μM). 2′-MeO-BDE-68 enhanced luciferase expression by 5nM T3 at 50μM. 6-MeO-BDE-47 exhibited potent antiandrogenicity at 1μM and greater (IC₅₀=41.8μM) and possessed estrogenic activity at 10μM and antiestrogenic activity at 10 and 50μM (IC₅₀=6.02μM).
Show more [+] Less [-]Persistent halogenated compounds in two typical marine aquaculture zones of South China
2011
Yu, Huan-Yun | Guo, Ying | Bao, Lian-Jun | Qiu, Yao-Wen | Zeng, E. Y. (Eddy Y.)
Samples of two seawater farmed fish (crimson snapper (Lutjanus erythopterus) and snubnose pompano (Trachinotus blochii)), water, air, sediment, fish feed, macroalgae and phytoplankton were collected from two estuarine bays (Daya Bay and Hailing Bay) in South China. The concentrations of persistent halogenated compounds (PHCs) including polybrominated diphenyl ethers (PBDEs), organochlorine pesticides and polychlorinated biphenyls (PCBs) varied widely with the different sample matrices under investigation. The compositional patterns in fish, fish feed, macroalgae and phytoplankton, as well as the good correlations between the abundances of p,p′-DDT and BDE-209 and their metabolites (i.e., p,p′-DDD and p,p′-DDE for p,p′-DDT and BDE-47 for BDE-209) in fish indicated the occurrence of DDT and PBDE biotransformation in fish body. Finally, the marine aquaculture environment in South China is somewhat biologically impaired by DDT-contaminated water, sediment and fish feed, and there may be some cancer risk associated with fish consumption for humans, especially for urban residents.
Show more [+] Less [-]The Fate of Polymeric Quaternary Ammonium Salts from Cosmetics in Wastewater Treatment Plants
2011
Cumming, Janet | Hawker, Darryl | Chapman, Heather | Nugent, Kerry
Polymeric quaternary ammonium salts or polyquaterniums used in cosmetics have been categorised as chemicals of concern in wastewater treatment plant (WWTP) effluent largely on the basis of emerging evidence of toxicity to aquatic organisms. However, little is known of their environmental fate and behaviour due to analytical difficulties with sample matrices. Their properties of negligible volatilisation and biotransformation enable the common fugacity-based model for WWTPs to be simplified to an equifugacity one where a compound has the same fugacity regardless of phase or position in the plant’s process train. To gain an appreciation of their fate, this approach is used to calculate removal efficiencies in WWTPs. These can be determined without calculating phase-specific fugacity capacity constants. To predict effluent concentrations however, an aquivalence approach is necessary because of the lack of volatility of these compounds. Using previously measured biosolids/water distribution coefficients for common polyquaterniums found in cosmetics and flow rate data from a local municipal WWTP in South East Queensland, Australia, the removal efficiencies of the polyquaterniums of interest are predicted to be only 25% or less, meaning relatively little attenuation in the WWTP. A Monte Carlo simulation shows a roughly normal distribution in the model output of polyquaternium removal efficiency, with a mean and mode of approximately 26%. A sensitivity analysis confirms that the model output is most sensitive to the magnitude of the biosolids/water distribution coefficient compound and shows WWTP data such as biosolids removal efficiency have only a relatively small effect.
Show more [+] Less [-]Effect of Metals on Decolorization of Reactive Blue HERD by Comamonas sp. UVS
2011
Jadhav, Umesh U. | Dawkar, Vishal V. | Kagalkar, Anuradha N. | Govindwar, Sanjay P.
Comamonas sp. UVS was able to decolorize Reactive Blue HERD (RBHERD) dye (50 mg L−1) within 6 h under static condition. The maximum dye concentration degraded was 1,200 mg L−1 within 210 h. A numerical simulation with the model gives an optimal value of 35.71â±â0.696 mg dye g−1 cell h−1 for maximum rate (Vmax) and 112.35â±â0.34 mg L−1 for the Michaelis constant (Km). Comamonas sp. UVS has capability of decolorization of RBHERD in the presence of Mg2+, Ca2+, Cd2+, and Zn2+, whereas decolorization was completely inhibited by Cu2+. Metal ions also affected the levels of biotransformation enzymes during decolorization of RBHERD. Comamonas sp. UVS was also able to decolorize textile effluent with significant reduction in COD. The biodegradation of RBHERD dye was monitored by UV–vis spectroscopy, FTIR spectroscopy, and HPLC.
Show more [+] Less [-]Accumulation, biotransformation, and biochemical responses after exposure to arsenite and arsenate in the estuarine polychaete Laeonereis acuta (Nereididae)
2011
Ventura-Lima, Juliane | Ramos, Patrícia Baptista | Fattorini, Daniele | Regoli, Francesco | Ferraz, Luís | de Carvalho, Leandro Machado | Monserrat, José M.
INTRODUCTION: This study aimed to analyze antioxidant responses and oxidative damage induced by two inorganic forms of arsenic (As; AsIII and AsV) in an estuarine polychaete species, Laeonereis acuta (Nereididae). The capacity of arsenic biotransformation was also evaluated through the methylation process considering the activity of a key enzyme involved in the metabolization process. MATERIALS AND METHODS: Worms were exposed to 50 μg (AsIII or AsV)/l during 2 or 7 days, plus a control group. Endpoints analyzed included concentration of reactive oxygen species (ROS), activities of antioxidant enzymes such as glutathione reductase (GR), total glutathione-S-transferase (GST), and omega isoform (GST Ω), glucose-6-phosphate deshydrogenase (G6PDH), levels of the antioxidant glutathione (GSH), and lipid peroxides concentration (TBARS). RESULTS AND DISCUSSION: Results showed: (1) GR inhibition after 2-day exposure to both As forms (p < 0.05); (2) GST Ω inhibition after 7-day exposure to AsIII paralleled by an increase in total GST activity (p < 0.05); (3) augmented G6PDH activity after 7-day exposure to both As forms (p < 0.05); (4) no differences in terms of ROS and TBARS; and (5) inhibition of GST Ω activity in AsIII exposed worms, which was concomitant with a lowering of mono- and dymethylated arsenic species. CONCLUSION: These results confirm the reactivity of some biochemical variables of L. acuta to As and indicates its importance as a sentinel species in estuarine regions with presence of arsenic.
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